Rozprawy doktorskie na temat „Cold-water immersion”

Cold water immersion (CWI) is the most effective known cooling treatment against exercise-induced hyperthermia. However, sex differences related to body composition (i.e. body fat, muscle mass, surface area, etc.) may affect core cooling rates in hyperthermic males and females. Purpose. To determine sex related differences in core cooling rates during CWI after exercise-induced hyperthermia. Methods. Ten male (M) and nine female (F) participants matched for body surface area to mass ratio took part in this study. Participants exercised at 65% V˙O2max at an ambient temperature of 40°C until rectal temperature (Tre) increased to 39.5°C. Following exercise, subjects were immersed in a 2°C circulated water bath until Tre decreased to 37.5°C. Results. Females had a significantly greater core cooling rate compared to males. This was paralleled by a lower skin temperature and a shorter time to reach the exit criterion. Conclusion. We conclude that previously hyperthermic females have a 1.7 times greater Tre cooling rate compared to males. We attribute this difference to a smaller lean body mass (expressed by the body-surface-area-to-lean-body-mass ratio) in females compared to males.

Objectives: Quantify the effects of cold water immersion of the ankle on fractioned response time of the dominant lower limb. Design and Setting: A 2x2x5x5 crossover design with repeated measures on time and treatment directed data collection. The independent variables were gender, treatment, time (pretreatment, and post 15 seconds, 3 minutes 6 minutes and 9 minutes) and trial (5 trials for each time group). Response time (Tresp), reaction time (Treac), trial and surface temperature were measurement variables. Subjects: Thirty-six subjects, 18 females and 18 males were recruited from a physically active volunteer college student population. Measurements: Fractioned response time was tested following a 20 minute treatment. Response time and Treac were recorded by the reaction timer, and Tmov was calculated by taking the difference between Tresp and Treac. For each time/subject the high and low Tresp were discarded and the middle three trials were averaged and used for statistical analysis. A 2x2x5 ANOVA was used to determine overall differences between gender, treatment and time followed by Newman-Keuls multiple comparison tests. Results: Males were faster than females for Tresp, Treac and Tmov. Movement time and Tresp were slower with cold water immersion, but Treac was unaffected. Movement time and Tresp were fastest pretreatment, and slowest during the post 15-second time group. Though both Tmov and Tresp progressively sped up from the post 15-second through the post 9-minute time group, they did not return to pretreatment values when data collection discontinued. Conclusions: Immersing the dominant ankle in cold water for 20 minutes increases Tmov of the dominant lower limb; thereby increasing fractioned response time (Tresp).

The purposes of this study were to (1) compare the pressor response between isometric exercise and a cold pressor test (CPT) and (2) examine the pressor response to isometric exercise at 33% of maximal voluntary contraction (MVC) combined with a CPT applied either at the onset or during the last minute of a 2-min CPT. Ten normotensive male volunteers performed isometric handgrip (HG) at 33% MVC, cold foot immersion, HG combined with a simultaneous CPT, and HG performed during the last minute of a 2-min CPT in a random order over three days. Systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP) and heart rate (HR) were recorded at rest and continuously throughout the tests. The results of this study indicate that (1) the pattern of HR response between the 2-min HG and the CPT was different; (2) DBP values during CPT for the initial 30s and the last 15s were significantly lower than DBP corresponding values during HG, while there were no significant differences between the CPT and HG with respect to SBP response; (3) when HG and CPT were performed simultaneously, the effects on SBP and HR were additive, whereas the effects on DBP and MAP were not; (4) CPT performed for 1 minute prior to HG attenuated the SBP and HR responses to HG at 33% MVC, and (5) although both HR and BP increased in response to HG at 33% MVC, only BP increased progressively in a linear fashion when combined with CPT. (Abstract shortened by UMI.)

Increases in core temperature are associated with perceptions of fatigue and reductions in physical work capacity. Following completion of a bout of exercise in the heat, cold water immersion (CWI) is sometimes used by athletes to rapidly decrease their core temperature, and may facilitate recovery. Few studies however, have examined the effects of CWI after exercise in the heat on short term recovery. In addition, whether or not performance benefits can arise from this recovery modality is equivocal. This thesis incorporates four individual studies surrounding the area of CWI recovery and one study that ,examined the reliability of a measure used to estimate blood flow. All of these studies have been published or submitted to refereed sport science journals.

A reduction in body temperature is considered to be the primary mechanism by which cold water immersion (CWI) enhances short-term (h) recovery and improves exercise capacity in the heat. However, improvement in exercise performance may be optimised at a given cooling magnitude. Water temperature and immersion duration influence the magnitude of cooling in the core body, muscle and skin. Given the role of blood flow in convective heat flux, substrate delivery and metabolic waste clearance, it is important to understand the influence of different water temperatures on compartmental distribution of limb blood flow during CWI. Therefore, the purpose of this study was to compare blood flow changes in the common femoral artery, vastus lateralis muscle, and thigh skin induced by 5 min of post-exercise water immersion at 8°C, 14°C, 35°C or passive rest. In a randomised manner, nine recreationally active men performed exhaustive cycling in a climate control chamber (32.8 ± 0.4°C and 32 ± 5%rh), followed by 5 min of water immersion at 8.6 ± 0.2°C (WI8), 14.6 ± 0.3°C (WI14), 35.0 ± 0.4°C (WI35) or passive rest (CON). The exercise task involved 25 min of cycling at a power output equivalent to first ventilatory threshold, followed by high-intensity intermittent cycling (30 s at 90% of peak power output to 30 s at 70 W). Measurement of blood flow in thigh skin (laser Doppler flowmetry), vastus lateralis muscle (near infrared spectroscopy), and common femoral artery (Doppler ultrasound), heart rate, mean arterial pressure, skin, muscle, rectal, and mean body temperatures were obtained prior to exercise and up to 60 min post-immersion. Both WI14 and WI8 reduced mean body, calf and thigh skin, and muscle temperatures, compared with WI35 and CON (p0.05). Relative to pre-immersion, differences were observed in the magnitude of reduction between skin, muscle, and common femoral blood flow. Decreases in muscle and skin blood flow were similar (p>0.05), but to a lesser extent when compared with femoral blood flow (p Therefore, 5 min of CWI at 8°C and 14°C effectively reduced temperatures, when compared with CON and WI35. Although WI8 was more effective than WI14 in reducing mean body temperature, there was no influence on the decreases in skin, muscle and femoral blood flow. Furthermore, WI8 did not result in significant reduction in muscle blood flow compared to WI35, despite significant muscle cooling. Given that mean arterial blood pressure was elevated, it is possible hydrostatic effects during WI35, coupled with shivering thermogenesis during WI8 confounded extent of muscle blood flow reduction in the present study. As such, influence of hydrostatic pressure per se on peripheral blood flow cannot be ruled out although blood flow changes were similar between WI35 and CON. Additionally, current findings indicate unknown vascular beds, other than measured sites in the vastus lateralis muscle and thigh skin, contribute to overall changes in the limb blood flow. It appears that vasoconstriction in skin and muscle vasculatures are associated with the interaction between suppressed vasodilatory substances (e.g. nitric oxide) and altered baroreflex mediated sympathetic nerve activity. However, underlying mechanisms warrant further investigation.

Many military and civilian personnel are required to work in situations where there is a risk of accidental immersion in the sea. Since immediate rescue may not be possible, it is important to predict the time for which survivors may remain alive. A computer-based mathematical model may provide a means of simulating the change in body temperature with time. The need for such a model and the physiological basis for its development have been investigated. A mathematical model has been developed in which the human body is visualised as 15 cylindrical or spherical segments, each divided into 10 radial shells of tissue. Passive heat flows are simulated at the surface and internally. Transport of heat by blood flow is represented in 120 arterial and venous compartments. The physiological mechanisms of thermoregulation are simulated, using existing physiological data. The model is implemented in structured FORTRAN 77 code. Although it is primarily configured for cold water immersion, infrastructure is included to permit adaption to simulate heat or cold stress in air. Code has been included for heat transfer through clothing and for exercising as well as resting conditions. Comparisons of the model predictions have been made against experimental data obtained from semi-nude immersions in water at 12, 18 and 24°C. For subjects with a relatively high body mass and fat content, the predicted body core temperature is generally within plus or minus one standard error of the experimental mean. For small, thin subjects at 12 and 18°C, the prediction is within two standard errors. The model does not cope well with sudden large changes in exercise but predictions for clothed subjects appear adequate.

This thesis examined the effect of differences in body surface area-to-lean body mass ratio (AD/LBM) on core temperature cooling rates during cold water immersion (2°C, CWI) and temperate water immersion (26°C, TWI) following exercise-induced hyperthermia (end-exercise rectal temperature of 40°C). Individuals with a High AD/LBM (315 cm2/kg) had a ~1.7-fold greater overall rectal cooling rate relative to those with Low AD/LBM (275 cm2/kg) during both CWI and TWI. Further, overall rectal cooling rates during CWI were ~2.7-fold greater than during TWI for both the High and Low AD/LBM groups. Study findings show that AD/LBM must be considered when determining the duration of the immersion period. However, CWI provides the most effective cooling treatment for EHS patients irrespective of physical differences between individuals.

The accumulated stresses of training and competition may temporarily cause impairments in an athlete’s physiological and muscular function, leading to suboptimal performance levels. Cold-water immersion (CWI) has become a widely used post-exercise recovery method to accelerate the recovery process by purportedly reducing the symptoms associated with exercise-induced muscle damage (EIMD). However, the underlying physiological mechanisms, which mediate the effects of CWI, are not well understood. Therefore, the aim of this thesis was to investigate the influence of cold-water immersion (CWI) on limb blood flow and thermoregulatory responses following different modes of exercise. In study 1 (Chapter 4), the reliability of Doppler ultrasound in the assessment of superficial femoral artery blood flow (FABF) was examined under resting conditions. A Doppler ultrasound scan of the superficial femoral artery was measured on eight recreationally active male participants; twice on the same day separated by 5-min (within-day), and on a separate day (between-days). The coefficient of variation (CV) for mean blood flow (MBF) was ~16 % and ~20 % for within and between-days, respectively. A relatively small standard error of measurement (SEM) was found both within day, 13.30 mL·min-1 (95% CI, -14.79 to 38.40 mL·min-1) and between-day, 17.75 mL·min-1 (95% CI, -40.12 to 30.88 mL·min-1) for MBF differences. These findings suggest duplex Doppler ultrasound is a reliable method to collect measurements of FABF under resting conditions. The purpose of study 2 and 3 was to determine the influence of different degrees of water immersion cooling on FABF and cutaneous blood flow (CBF) and thermoregulatory responses after endurance (Chapter 5) and resistance (Chapter 6) exercise, respectively. Participants completed a prescribed endurance of resistance exercise protocol prior to immersion into 8 ºC (cold) or 22 ºC (cool) water to the iliac crest or rested non-immersion (CON) in a randomized order. Limb blood flow and thermoregulatory responses were measured before and up to 30-min after immersion. In both studies, thigh skin temperature (Tskthigh) (P < 0.001) and muscle temperature (Tmuscle) (P < 0.01) were lowest in the 8 ºC trial compared with 22 ºC and control trials. However, femoral artery conductance (FVC) was similar after immersion in both cooling conditions and was reduced (~50-55 %) compared with the CON condition 30-min after immersion (P < 0.01). Similarly, there was a greater thigh (P < 0.01) and calf (P < 0.05) cutaneous vasoconstriction during and after immersion in both cooling conditions relative to CON with no differences noted between 8 and 22 ºC immersion. Together, these findings suggest that colder water temperatures may be more effective in the treatment of EIMD and injury after both endurance and resistance exercise, respectively, due to greater reductions in Tmuscle and not limb blood flow per se. The aim of study 4 (Chapter 7) was to compare the influence of CWI and whole body cryotherapy (WBC) on FABF and CBF and thermoregulatory responses after endurance exercise. On separate days, participants completed a continuous cycle ergometer protocol before being immersed semi-reclined into 8 ºC water to the iliac crest for 10 min (CWI), or exposed to 2.5 min (30 s -60 ºC, 2 min -110 ºC) WBC in a specialized cryotherapy chamber, in a randomized order. Limb blood flow and thermoregulatory responses were measured before and up to 40-min after immersion Reductions in Tskthigh (P < 0.001) and Tmuscle (P < 0.001) were larger in CWI during recovery. Similarly, decreases in FVC were greater (~45-50 %) in the CWI condition throughout the recovery period (P < 0.05). There was also a greater skin vasoconstriction observed in CWI at the thigh (P < 0.001) and calf (P < 0.001) throughout the post-cooling recovery period. These results demonstrate that CWI may be a better recovery strategy compared with WBC due greater reductions in both Tmuscle and limb blood flow. This thesis provides a novel insight into the influence of different degrees of water immersion cooling, as well as WBC, on limb blood flow and thermoregulatory responses after different modes of exercise. These findings provide practical application for athletes and an important insight into the possible mechanisms responsible for CWI in alleviating inflammation in sport and athletic contexts.

The balance between the stress of training and competition and sufficient recovery is critical within the development of athletic performance. This stems from the need to recover between successive intense periods of exercise and provide sufficient time through which to adapt to the prescribed training stimulus. Cold water immersion (CWI) is now widely used by athletes to enhance the rate of recovery following training and competition. However, little information currently exists with respect to its influence on skeletal muscle adaptation. Therefore, the aim of this thesis was to investigate the impact of CWI on acute markers of adaptation in human skeletal muscle following low-damaging high-intensity intermittent exercise. The aim of study 1 (Chapter 4) was to devise a low-damaging high-intensity intermittent running protocol which would be used as the criterion mode of exercise in future studies within the thesis. The exercise was comprised of 60-min of high-intensity intermittent exercise (8 × 3-min bouts at 90% V ̇O2max interspersed with 3-min recovery) on a motorised treadmill. No significant reduction in maximal voluntary contraction of the quadriceps was observed immediately following completion of the exercise protocol or during the subsequent 7 d period compared to pre-exercise values (P = 0.59). Creatine Kinase (CK) concentrations remained similar to baseline following exercise (P = 0.96). Myoglobin (Mb) content increased following exercise (P = 0.01). However, values returned to baseline after 24 h (P = 0.32). These results suggest the high-intensity intermittent running protocol induced changes in physiological and subjective indices consistent with the effects of low muscle damaging as opposed to those changes normally associated with exercise-induced severe muscle damage. The purpose of the second study (Chapter 5) was to examine the effects of CWI (2 × 5-min (8oC)) on acute markers of skeletal muscle adaptation at rest. Rectal temperature remained similar throughout the CWI protocol (P = 0.36). However, significant reductions in skin (thigh and calf) and muscle temperature were observed immediately post-immersion and the post-immersion period (P < 0.05). Noradrenaline was significantly increased 3 h (355.7 ± 181pmol/l) and 6 h (390.9 ± 131pmol/l) post-immersion compared to baseline (P < 0.01). Muscle PGC-1α (3 h, 1.3 ± 0.2-fold; 6 h, 1.4 ± 0.3-fold) and VEGF165 (3 h, 1.9 ± 1.4-fold; 6 h, 2.2 ± 1.0-fold) mRNA expression were significantly increased at 3 h (PGC-1α, P < 0.001; VEGF165, P = 0.03) and 6 h (PGC-1α, P < 0.001; VEGF165, P = 0.009) post-immersion, respectively. These results indicate that CWI enhances the upstream signalling pathways associated with mitochondrial biogenesis and angiogenesis in human skeletal muscle at rest. The aim of the third study (Chapter 6) was to establish whether post-exercise CWI further enhances the upstream signalling pathways associated with mitochondrial biogenesis and angiogenesis in human skeletal muscle. On each occasion, participants rested passively (Cont) or undertook 2 × 5-min of CWI (8oC) at twenty minutes after completing the intermittent exercise protocol. Rectal temperature remained similar between CWI and Cont conditions during the 3 h post-exercise recovery period (P > 0.05), however, skin (thigh and calf) and muscle temperature were reduced in the CWI condition compared to Cont (P < 0.05). PGC-1α mRNA expression was significantly increased 3 h post-exercise under both conditions (CWI, P < 0.001; Cont, P = 0.003) with greater expression observed in CWI (CWI, 5.9 ± 3.1-fold; Cont, 3.4 ± 2.1-fold; P < 0.001). VEGF165 and VEGFtotal mRNA were greater in CWI (2.4 ± 0.6-fold, 2.3 ± 0.4-fold) compared with Cont (1.3 ± 0.5-fold, 1.0 ± 0.3-fold) at 3 h post-exercise (P = 0.01, P < 0.001). These findings demonstrate that post-exercise CWI increases the expression of upstream signalling pathways associated with mitochondrial biogenesis and angiogenesis in human skeletal muscle compared with exercise alone. Study 4 (Chapter 7) examined the influence of the repeated post-exercise CWI on upstream signalling pathways associated with mitochondrial biogenesis and angiogenesis in human skeletal muscle. On each occasion, participants rested passively or undertook 3 × 10-min of CWI (8oC) at twenty minutes after completing the intermittent exercise protocol, 1 h and 2 h post-exercise. Rectal temperature was reduced during the 3rd bout of CWI and subsequent 30-min period compared to Cont (P < 0.05). Skin temperature (thigh and calf) remained consistently lower during the immersion periods in CWI compared with Cont (P < 0.05). Muscle temperature was reduced before the 2nd bout of CWI (-5.8 ± 0.3oC) compared with Cont (-1.9 ± 0.4oC) and remained until 50-min after the 3rd immersion (P < 0.05). Noradrenaline were significantly greater at 3 h and 6 h following exercise in CWI (662 ± 139pmol/l, 518 ± 158pmol/l) compared with Cont (307 ± 162pmol/l, 245 ± 156pmol/l) (P < 0.05). PGC-1α mRNA expression was higher after 3 h post-exercise in the Cont (2.4 ± 1.7-fold) than CWI (1.8 ± 1.0-fold) conditions respectively (P = 0.06). At 6 h post-exercise, PGC-1α mRNA expression was greater in CWI (2.6 ± 1.4-fold) compared to Cont (1.7 ± 1.7-fold) (P = 0.03). VEGF165 and VEGFtotal mRNA increased more than ~1.6-fold at 3 h and 6 h following exercise and were similar between conditions (P > 0.05). These results indicate that increasing the repeated post-exercise CWI does not further increases the expression of upstream signalling pathways associated with mitochondrial biogenesis and angiogenesis in human skeletal muscle. This thesis provides novel findings concerning the influence of high-intensity intermittent exercise and post-exercise CWI on cellular and molecular adaptations in human skeletal muscle. These findings may offer important insights for athletes wishing to maximize training adaptations.

In most team sports, a cycle of training, competition, and recovery repeatedly occurs over each week of a competitive season. For athletic performance to be maintained through a season, an optimal balance between training and recovery is required. To facilitate the recovery process after competition games and training, hydrotherapy has been adopted by a number of sporting teams. Methods: In the present thesis a review of literature was undertaken to identify the most commonly investigated methods of recovery in professional sport. Pilot studies were then conducted across periods of four weeks. The review of literature highlighted the need for research into recovery to examine beyond the acute phase. To address the need to examine recovery beyond the acute phase the major study evaluated three related questions: Firstly, the effectiveness of hydrotherapy for recovery in the first 48h after a simulated game: Secondly, the effectiveness of hydrotherapy for recovery across a cyclic week, including a simulated game and three training sessions: Thirdly; the effectiveness of hydrotherapy for recovery as measured across performance in two simulated Rugby Union games. A simulated game of Rugby Union previously used in evaluating factors affecting performance in Rugby Union was adopted as the key physiological stressor: Finally, to accommodate and compare the studies within this thesis with the increasing volume of published literature evaluating hydrotherapy for recovery in team sport, a systematic review with meta-analysis was carried out. Male Rugby Union players (n=24) were recruited to participate in this research. Participants were randomly assigned to one of three groups. A cold water immersion (CWI) group underwent two cycles of 5 minutes at 10oC, a contrast water therapy (CWT) group underwent 5 cycles (1 minute alternating immersions at 10oC/40oC) and a control group underwent passive recovery, which involved being seated for 15 minutes. Within group and between group analyses were conducted using an ANOVA model with baseline scores as covariates for each of the three research questions. Post hoc analysis was conducted manually, with each time point as the covariate and analysed individually against each time point. Effect sizes were calculated as partial eta2 (ηp2) (omnibus) and Cohen‟s d (univariate).

This study examined the extent to which physiological and psychological concomitants of aerobic terrestrial performance were affected by body cooling of varying degrees induced by cold water immersion (CWI). Thirteen male and 13 female subjects underwent three randomly assigned 30 min treadmill runs: a control run without prior manipulation of the subjects' thermal status and the same exercise after "central" (core temperature 1°C below pre-immersion) and "peripheral" cooling (skin heat loss 100kcal.m⁻².h⁻¹). During treadmill runs core temperature was measured, together with chest, leg, arm and hand temperatures, from which mean skin temperature (T [subscript]s[subscript]k) and mean body temperature (T[subscript]b) were calculated. Heart rate, oxygen consumption (VO₂,), carbon dioxide production (VCO₂), minute ventilation (V₂ (BTPS)), breathing frequency (f), cadence and ratings of perceived exertion (RPE) and thermal sensation (PTS) were also measured. Both central and peripheral cooling resulted in significantly reduced T[subscript]r[subscript]e (males : control 37.9±0. 3°C; central cooling : 36.8±0.5°C; peripheral cooling: 37.5±0.4°C; females: control: 37.9±0.4°C; central cooling: 37.2±0.5; p<0.05) during subsequent treadmill running, except following peripheral cooling for females (37.9±0.3°C) . For males and females T[subscript]s[subscript]k was lower following peripheral cooling than control values and lowest after central cooling (males: control: 30.0±1.3°C; central cooling: 36.8±0.5°C; peripheral cooling: 37.5±0.4°C; females: control: 30.5±1.2°C; central cooling: 25.9±1.8°C; peripheral cooling: 26.9±1.9°C; p<0.05). Female subjects experienced significantly higher T[subscript]r[subscript]e than males following central and peripheral cooling and a lower T[subscript]s[subscript]k following central cooling. Females experienced less of an increase in heart rate than males during exercise following central and peripheral cooling (control: l57.7±23.7b.min⁻¹; central cooling: 143.5±20.5b.min⁻¹; peripheral cooling 151.7±16.7b.min⁻¹; p<0 .05). Male responses were the same following central cooling but higher for peripheral cooling than control values (control: 139.1±7.3b.min⁻¹; central cooling 134.7±17.5b.min⁻¹; peripheral cooling: 145.0±16.4b.min⁻¹; p<0.05). These data indicate a depression in cardiovascular function for females following peripheral cooling that was not apparent for males. The VO₂ was not different between tests for males; only peripheral cooling resulted in a raised VO₂ of 28.6±3 .3ml.kg⁻¹.min⁻¹ (p<0 .05) for females compared to 27.6±2.6ml.kg⁻¹.min⁻¹ (control). A biphasic response was evident for VO₂ VCO₂ and V[subscript]B (BTPS). For both sexes overall RPE was lower for peripheral cooling (males: 9.4±1.9; females: 8.7±1.3; p<0 .05) than for control and central cooling. Central RPE was only changed for females following peripheral cooling. Changes in cadence and step length together with the effect of low skin and leg temperatures resulted in higher local RPE for females after central cooling (9.6±1.2; p<0.05) than control (9.4±1.9) and peripheral cooling (8.9±1.2 ). Males and females rated the same ambient temperature during the same exercise lower after peripheral cooling (males: 4.6±1.5; females : 5.3±1.3) than control values and lower still after central cooling (males: 3. 8±1.8; females: 2 .7±l. 5) In this study T[subscript]s[subscript]k was the primary determinant of PTS after precooling.
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In the last few years researchers have more and more focussed on the possible use of cryotherapy as an acute and long term recovery facilitating technique by sportsmen and women. Barnette (2006) did, however, state that research supporting cryotherapy as a recovery facilitating technique, is not convincing and that the majority of research show that it has a negative impact on the recovery of subjects after exercise. It is against this background that the aim of the study was firstly to critically analyse the available literature of the past fifteen years (1992-2007) with regard to the study subject; die nature of the cryotherapy technique that was used as well as the findings with regards to the effects of these types of techniques on a wide variety of physiological variables, physical and motor performance; secondly, to provide guidelines for the use of cryotherapy as a recovery facilitating technique and thirdly to determine the effect of cryotherapy on the acute recovery of University netball players' lower leg muscles in an isokinetic ankle exercise. Firstly, it was shown that ice water immersion and ice pack application are the most common techniques that are used in cryotherapy studies. The results in the majority of articles indicated that cryotherapy had a non-significant acute effect on isokinetic, eccentric and concentric peak torque as well as time to reach peak torque and the angle at which the peak torque was reached; isometric, maximal and sub-maximal strength and accuracy of strength execution; normalized, average vertical ground reaction force as well as time of reaching peak power and vertical jump height; baseball pitching accuracy, proprioception, ankle joint range of movement, positioning and speed during execution of a movement; blood lactate removal and blood flow speed as well as muscle soreness after completion of an exercise. With regard to the long term effects of cryotherapy research showed that isotonic hand grip strength and endurance, plasma adrenaline, non-adrenaline, dopamine, renine, aldosterone, heart rate and blood pressure after 6 weeks; respiratory gas exchange ratio, heart rate, muscle glycogen concentration, plasma lactate, glucose and free fatty acids after 8 weeks or brachial artery cross-section and vascular endothelial growth factor after 4 weeks of exercise and cryotherapy did not experience any significant changes between the cryotherapy and control group. Other physical, motor performance and physiological variables did not show a certain trend with regards to the way they were affected by cryotherapy. In some cases variables were affected significantly negatively while the opposite was true in other cases where variables were significantly positively influenced. With regard to the results of the study on the acute recovery of University netball players' lower leg muscles due to cryotherapy, it was found that the acute recovery of only four isokinetic variables were significantly influenced (p = 0.05) by cryotherapy, namely: left leg relative total dorsiflexion work, average peak dorsiflexion torque, right dorsiflexion and plantar flexion endurance. The acute recovery of the first mentioned strength endurance related variable was significantly negatively influenced by the cryotherapy. In contrast with this result the acute recovery of the three last mentioned isokinetic muscle relative peak torque and endurance related variables were significantly positively influenced by the cryotherapy. The overall conclusion that can therefore be drawn from the above-mentioned results show that the majority of isokinetic plantar- and dorsiflexion torque variables (12 out of 16, 75%) as well as other physical, motor performance and physiological variables experience no significant effect with regards to acute and long term recovery due to cryotherapy. The research did, however, show that the effectiveness of cryotherapy was influenced by the adiposity thickness, nature of the cryotherapy application, type of medium that was used for cryotherapy application and the length of time during which cryotherapy was applied. The recommendation for the use of cryotherapy as a recovery facilitating technique can be summarised as follows: the temperature of the cryotherapy medium that is used, must vary between 5°C and 10°C; the duration of cryotherapy between 15 and 20 minutes; the most general application area: for ice water immersion - immersed up until the level of the gluteal fold or crista ileac and the whole arm or forearm; for ice pack application - on the thigh, ankle and peripheral of the shoulder; the most common and effective ice pack application is direct on the skin surface by means of a bag filled with between 500 g and 1 500 g cubic formed ice. For long term use more that 2 consecutive days of cryotherapy application is recommended.
Thesis (M.A. (Human Movement Science))--North-West University, Potchefstroom Campus, 2008.

Background Heat acclimation and precooling are strategies commonly used to mitigate heat stress during exercise in the heat. Physiological adaptations during heat acclimation include lower core temperature (Tcore), lower heart rate (HR), and increased sweat output during exercise at a given workload. Adjusting the training intensity to meet specific energetic demands during heat acclimation may be as important for performance improvements. However, the challenge of maintaining the quality of training during heat exposure without concomitant accumulative fatigue remains. Precooling presents a potential strategy to maintain the quality of training during heat exposure but may have some inhibitory effects on thermoregulatory adaptations. Of the various precooling techniques, cold water immersion (CWI) and ingestion of ice slushy (ICE) are different in terms of application (external versus internal) and their ensued effects on the sweat response, skin temperature (Tsk) and Tcore. Therefore, the primary purpose of this thesis was to examine the effects of CWI and ICE on sudo- and vasomotor responses and adaptations to heat acclimation. Aims Study 1 aimed to determine the effects of ICE and CWI on the psychophysiological responses and endurance exercise performance through meta-analysis. Subsequently, two studies were conducted to: 1) examine the effects of CWI and ICE on the changes in rectal temperature (Tre) and Tsk, perceived thermal sensation and sweat responses during constant-paced exercise in the heat; and 2) determine the effects of altered physical thermal state (Tre and Tsk) and perceived thermal sensation following ICE and CWI on thermoregulatory behaviour (i.e., total work output and mean power output [MPO]) during cycling in the heat. Finally, the purpose of study 4 was to investigate the influence of regular precooling by CWI as part of a heat acclimation regimen on thermoregulatory adaptations and changes in exercise performance. Methods For study 1, 22 studies were included in the meta-analysis based on the following criteria: 1) cooling was performed with ICE or CWI before the exercise; 2) exercise longer than 6 min was performed in ambient temperature ≥ 26°C; and 3) crossover study design with a noncooling passive control condition. Weighted average effect sizes in Hedges’ g and 95% confidence intervals (CIs) were calculated from the mean difference and pooled SD. Studies 2 and 3 were randomised crossover studies with three conditions (ICE, CWI and no cooling control [CON]). The participants in studies 2 and 3 were recreationally active males aged between 19-40 y. Each trial was preceded by 30 min of CWI (22.0 ± 0.2°C), ICE (- 0.3 ± 0.4°C) or CON. In study 2, 11 men cycled at 40 or 50% of peak aerobic power for 60 min (33.2 ± 0.3°C, 45.9 ± 0.5% relative humidity [RH]). In study 3, 11 men cycled for 60 min at perceived exertion (RPE) equivalent to 15 (i.e., “hard”) (33.9 ± 0.2°C and 42.5 ± 3.9% RH). Local sweat rate was measured by capacitance hygrometry. Using near-infrared spectroscopy and laser Doppler flowmetry, changes in muscle blood volume and oxygenation and skin perfusion were examined. In study 4, 20 male recreational triathletes and cyclists (27-50 y) completed 10 sessions of 60-min cycling at RPE 15 within 14 days in the heat (35.3 ± 0.3°C, 53.4 ± 1.9 % RH), preceded by no cooling (CON, n = 10) or 30 min of CWI at 21.9 ± 0.5°C (PRECOOL, n = 10). Only 19 participants (n = 9 and 10 for CON and PRECOOL, respectively) completed heat stress tests before and after heat acclimation, which involved 25 min of cycling at 60% V̇O2peak and a 20- km time trial in the heat (35.3 ± 0.2°C, 53.8 ± 0.7% RH). Results The meta-analysis (study 1) revealed that CWI improved exercise performance (Hedges’ g [95CI] +0.53 [0.28; 0.77]) and resulted in greater increase (ΔEX) in Tsk (+4.15 [3.1; 5.21]) during the exercise. Additionally, lower peak Tcore (-0.93 [-1.18; -0.67]), whole body sweat loss (-0.74 [-1.18; -0.3]), and thermal sensation (-0.5 [-0.8; -0.19]) were observed without concomitant changes in ΔEX-Tcore (+0.19 [-0.22; 0.6]), peak Tsk (-0.67 [-1.52; 0.18]), peak HR (-0.14 [-0.38; 0.11]), and RPE (-0.14 [-0.39; 0.12]). ICE had no clear effect on exercise performance (+0.2 [-0.07; 0.46]) but resulted in greater ΔEX-Tcore (+1.02 [0.59; 1.45]) and ΔEX-Tsk (+0.34 [0.02; 0.67]) without concomitant changes in peak Tcore (-0.1 [-0.48; 0.28]), peak Tsk (+0.1 [-0.22; 0.41]), peak HR (+0.08 [-0.19; 0.35]), whole body sweat loss (-0.12 [- 0.42; 0.18]), thermal sensation (-0.2 [-0.49; 0.1]) and RPE (-0.01 [-0.33; 0.31]). In studies 2 and 3, ICE decreased Tre by ~0.3°C during precooling, compared with CON and CWI (p < 0.05). CWI decreased Tsk by ~4°C (p < 0.05) during precooling, compared with CON but did not have any significant cooling effect on Tre. In both studies, ICE decreased Tre- Tsk gradient during the first 5 min of exercise when compared with CON (p < 0.05), and CWI increased Tre-Tsk gradient during the initial 15-20 min of exercise when compared with CON and ICE (p < 0.05). In both studies, CWI (p < 0.001) and ICE (p = 0.019) delayed sweat recruitment by 1-5 min, compared with CON but did not significantly affect the body temperature threshold for sweating. In studies 2 and 3, muscle blood volume was decreased during CWI and during the initial 10-20 min of exercise when compared with CON and ICE (p < 0.05); however, there was no significant condition effect on muscle oxygenation. In study 2, mean HR during the exercise was decreased by ~5 bpm in CWI when compared with CON only (p = 0.025). In study 3, thermal sensation was lower in CWI for up to 35-40 min during the exercise, compared with CON and ICE (p < 0.05). Additionally, thermal sensation was lower in ICE than in CON during the first 20 min of exercise (p < 0.05). Thigh skin perfusion was decreased during CWI (p = 0.012) and ICE (p = 0.044), compared with CON but was not different between conditions during the exercise (p > 0.05, study 3). MPO was greater in CWI when compared with CON only (p = 0.024, CON: 130 ± 20 W, ICE: 128 ± 25 W, CWI: 138 ± 18 W, study 3). In study 4, changes in MPO (p = 0.024) and HR (p = 0.028) during heat acclimation were lower in CON (MPO: 97.4 ± 8.1%, ΔHR: -7 ± 4 bpm) than in PRECOOL (MPO: 102.9 ± 6.6%, ΔHR: -1 ± 7 bpm). HR during cycling at 60% V̇O2peak was decreased from the first heat stress test in both groups (p < 0.001). Tre, Tsk, sweat responses, Tre threshold and sensitivity for sweating, thigh skin perfusion, thermal sensation and RPE during the heat stress tests were not affected by heat acclimation in both groups (all p > 0.05). MPO (p = 0.016, Cohen’s effect size [d] = 0.93) and finish time (p = 0.013, d = 0.97) for the 20-km time trials were improved from the first heat stress test in PRECOOL but were not significantly changed in CON (MPO: p = 0.052 and d = 0.76, finish time: p = 0.140 and d = 0.54).

Victims of exertional heat stroke (EHS) in whom treatment is delayed have higher rates of multi-organ failure and a greater number of fatalities. Death related to EHS is preventable, through immediate treatment via cold-water immersion (CWI). To date little is known about the influence of treatment delays on core cooling following EHS. Thus we sought to examine the effects of treatment delays on cardiovascular and thermal responses prior to, during, and following CWI treatment in individuals with exercise-induced hyperthermia. Our findings demonstrate that treatment delays resulted in a sustained level of hyperthermia and cardiovascular strain that significantly increased the time an individual is at risk to the potential lethal effects of EHS. Moreover, we report that cold water immersion treatment is powerful enough to overcome the adverse effects of treatment delays and rapidly reduce core temperatures while facilitating the re-establishment of blood pressure towards normal resting levels.

Swimming is the most popular participation sport in the UK with open water swimming seeing a rise in popularity over the last decade. However, cold water immersion is not without significant risks. Drowning represents the third leading cause of accidental death worldwide and in those aged 1 to 14 years it represents the leading cause of accidental death in some countries. Given the physical, physiological and psychological differences between adults and children, the latter are considered particularly at risk of cold-related illness and hypothermia. The 'cold shock' response on initial immersion, and the insidious onset of hypothermia and swim failure that accompanies prolonged exposure and swimming, are recognised to be potentially fatal. This has been well documented in adults, and whilst it is assumed that similar responses occur in children there is little quantitative evidence of this to date. Furthermore, adults show an habituation of their 'cold shock' response and change in their cooling rates following repeated exposure to cold water, however there are no data that show similar changes in children. This study examined the physiological and subjective responses of children to cold water on initial immersion and on prolonged immersion whilst swimming, and assessed for any adaptation in these responses following a year of repeated swim training in cold water. It was hypothesised that: children would demonstrate a 'cold shock' response on initial immersion that would habituate following a period of acclimatisation; children would demonstrate faster cooling rates than those seen in adults whilst swimming in cold water, and their rate of cooling would adapt over a year of cold water swim training. METHOD 17 children aged 10 and 11 years old were recruited from applicants to the Bristol English Channel Swim Team (an attempt by a group of children to be the youngest relay team to swim the Channel). They underwent a five-minute static immersion in 15 QC water, during which their cardiovascular, respiratory and metabolic responses were recorded. Ten of these participants went on to swim for up to 40 minutes in 15 QC water, during which their heart rates, gastrointestinal temperatures and oxygen consumption were measured. The gastrointestinal temperatures of participants during the re- warming phase (post immersion) was also monitored and recorded. Subjective thermal sensation and comfort were recorded prior to immersion, after five minutes static immersion, and at the end of the swims. Following a year of regular cold water swim training, eight participants returned to complete the five-minute static immersion and five of the original ten swimmers completed a swim of up to 40 minutes in 15 QC water. This allowed us to identify any evidence of adaptation in their 1 initial responses to immersion in cold water and cooling rates whilst swimming. The data gathered were compared to adult data collected in the same laboratory during a different experiment. RESULTS An increase in heart rate, respiratory frequency and inspiratory volume was seen in all participants in the first few minutes of immersion. However, responses were found to be smaller in children compared to adul~s (P < 0.05), and no significant attenuation was seen in these after a year of regular exposure to cold water. Children did however feel warmer (P < 0.01) and more comfortable (P < 0.05) following five minutes of static immersion after a year of cold water swim training. There was great variability in the rate of cooling between children, likely due to differences in their anthropometric profiles. Sum of skinfolds was found to hold the greatest correlation with rate of deep body cooling (R2 = 0.4157). The mean (SD) cooling rate of the children whilst swimming was 2.5 (3.06) °C.h-1. No statistical difference was found in the cooling rates of five children following a year of cold water swim training. No difference was found between children and adults in their cooling rates whilst swimming, however the trend in both groups of a slower rate of cooling following acclimatisation became significant (P = 0.026) once the child and adult data were pooled. DISCUSSION This study provides evidence that the 'cold shock' response exists III children, but is possibly smaller than that seen in adults. The lack of attenuation in this response following acclimatisation is a surprising finding that warrants further investigation, although it may be that the children were pre-acclimatised prior to their initial immersion, or due to a small sample size. This study provides quantitative data on cooling rates of children swimming in cold water. It finds that children maintain their deep body temperature as effectively as adults, which is likely partly explained by a greater percentage body fat (P < 0.05) and higher relative heat production, as measured by oxygen consumption (P < 0.05), seen in the children. The data support an habituation of children's subjective thermal awareness and goes some way to suggest that children aged 11 - 12 years old exhibit an insulative adaptation following regular swimming in cold water. It is hoped that this study provides a better understanding of children's physiological responses to accidental and non- accidental immersion, and will aid risk assessments in any projects involving paediatric immersion in cold water.

Background Exercising at different levels of intensity is associated with an acute inflammatory response as a result of muscle damage, which consequently leads to delayed onset muscle soreness (DOMS). Cold-water immersion (CWI) has shown the potential to reverse exercise related muscle inflammation and enhance post-exercise recovery following sport activities. Several studies have investigated the effect of CWI on muscle recovery, however, their results are controversial. The purpose of the current study was to examine the physiological response of CWI on healthy participants and explore the physiological and psychological effect of CWI on athletes compared with controls. Methods Phase one observed the physiological response of 9 healthy active volunteers immersed in 12-13° for 15 minutes. Heart rate (HR), blood pressure (BP) and O2 consumption were measured and monitored. Inflammatory biomarkers and muscle strength were observed prior to immersion, 30 minute and 24 hour following CWI. Phase two used a randomized crossover trial to study the effectiveness of CWI [15 minutes of CWI at 12-13°C] compared to passive recovery [15 minutes sitting] post delayed onset muscle soreness in 8 elite male rugby players. Inflammatory biomarker, muscle strength, were measured prior to the intervention and 30 minutes, 24 and 48 hour post intervention. Muscle soreness [VAS and pain pressure threshold] was measured 20 minutes, 24 and 48 hours post intervention. Phase three explored the psychological effect of CWI using a focus group and self-administered questionnaire. Result In Phase one, CWI produced no significant changes in cardiovascular function, oxygen consumption, muscle strength and hormone concentration levels. In Phase two, CWI reduced immediate quadriceps muscle soreness by (5 unit) compare to passive group by (15 unit) (P=0.006). No effect on strength or inflammatory cytokines compared to passive recovery. In Phase three, athletes reported a perception of improved performance and reduction in pain when using CWI. Conclusion CWI has positive effects for the treatment of DOMS. Physiologically it reduces immediate muscle tenderness, but does not affect muscle strength. Psychologically athletes perceive an improvement in performance and reduction in pain.

Previous data have shown that the most prevalent, indirect plasma volume (PV) measurement technique, which utilises changes in haematocrit (Hct) and haemoglobin concentration ([Hb]), underestimates actual PV changes during immersion, when compared to a direct tracer-dilution method. An increase in the F-cell ratio (whole-body haematocrit (Hctw) to large-vessel haematocrit (Hctv) ratio) has been purported as a possible explanation, probably due to hydrostatic and thermally-mediated changes during water immersion. Previous investigators have not quantified the F-cell ratio during immersion. Therefore, this study sought to determine the effect of the F-cell ratio on the indirect method during both, thermoneutral and cold-water immersions. Seven healthy males were tested three times, seated upright in air (control: 21.2°C SD ±1.1), and during thermoneutral (34.5oC SD ±0.2) and cold-water immersion (18.6oC SD ±0.2), immersed to the third intercostal space for 60 min. Measurements during the immersion tests included PV (Evans blue dye column elution, Evans blue dye computer programme, and Hct [Hb]), red cell volume (RCV; sodium radiochromate), cardiac frequency (fc) and rectal temperature (Tre). Plasma volume during the control trial remained stable, and equivalent across the three tests. There was a hydrostatically-induced increase in PV during thermoneutral immersion, when determined by the Evans blue dye method (16.2%). However, the Hct/[Hb] calculation did not adequately reflect this change, and underestimated the relative PV change by 43%. In contrast, PV decreased during cold immersion when determined using the Evans blue dye method by 17.9% and the Hct/[Hb] calculation by 8.0%, respectively, representing a 52% underestimation by the latter method. There was a non-significant decline in RCV during both immersions. Furthermore, an increase (8.6%) and decrease (-14.4%) in blood volume (BV) was observed during thermoneutral and cold-water immersions, respectively. The decline in RCV during thermoneutral immersion attenuated the BV expansion. Despite the disparity between the PV methods, there was no increase in the F-cell ratio during either immersion. In contrast, there was a significant decline in the F-cell ratio during the control: air and thermoneutral immersion, which may indicate that other, undefined variables may impact on the stability of the red cell compartment. The current study is the first to show that the Hct/[Hb] method clearly underestimates PV changes during both thermoneutral and cold-water immersion. Furthermore, RCV was shown, for the first time, to decline during both immersions. However, the changes in the F-cell ratio during this study, did not account for the underestimation of PV change using the Hct/[Hb] method.

Projeto de Graduação apresentado à Universidade Fernando Pessoa como parte dos requisitos para obtenção do grau de Licenciado em Fisioterapia
Introdução: a imersão em água fria é frequentemente utilizada na prática desportiva após a realização do exercício, com o objetivo de diminuir os danos musculares tanto numa fase aguda (alterações metabólicas), como numa fase mais tardia (dor muscular). Objetivo: avaliar o efeito da imersão em água fria no sistema muscular após a realização de exercício físico intenso, em indivíduos saudáveis/ativos/desportistas. Metodologia: a pesquisa foi realizada na base de dados Pubmed e PEDro, com artigos randomizados controlados, dos últimos 10 anos até á atualidade. Após a seleção dos estudos foi efetuada uma análise da qualidade metodológica através da escala de PEDro. Resultados: foram selecionados seis artigos, cuja a classificação metodológica obteve uma média de 5/10 na escala de PEDro. Os estudos incluíram um total de 116 participantes, com idades compreendidas entre os 19,9 e os 24 anos de idade. A imersão em água fria foi utilizada como técnica de recuperação após a realização de exercício físico, mas sempre comparada com outra técnica (recuperação ativa ou passiva). Conclusão: constatou-se que o banho de imersão em água fria promove um maior alívio na dor muscular, um menor dano muscular, uma contenção no aumento da massa muscular, e uma perceção mais positiva relacionada com a recuperação muscular.
Introduction: cold water immersion is often used in sports after exercise, with the aim of reducing muscle damage both in an acute phase (metabolic changes) and in a later phase (muscle pain). Objective: to evaluate the effect of immersion in cold water on the muscular system after intense physical exercise, in healthy / active / sports individuals. Methodology: the research was carried out in the Pubmed and PEDro database, with randomized controlled articles, from the last 10 years to the present. After selecting the studies, an analysis of the methodological quality was performed using the PEDro scale Results: six articles were selected, methodological classification obtained an average of 5/10 on the PEDro scale. The studies included with a total of 107 participants, aged between 20 and 28 years old. Cold water immersion was used as a recovery technique after physical exercise, but always compared with another technique (active or passive recovery). Conclusion: it was found that the immersion bath in cold water promotes greater relief in muscle pain, less muscle damage, restraint in increasing muscle mass, and a more positive perception related to muscle recovery.
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Endurance training results in profound skeletal muscle adaptations that improve fatigue resistance and enhance exercise capacity. To maximise these adaptations, athletes often engage in extensive training regimes, involving 10 to 16 training sessions∙wk-1. The use of cold water immersion (CWI) as a recovery intervention has emerged as a strategy to maintain training performances between sessions. However, its concurrent influence on muscle aerobic adaptations to training is unclear. Thus, the overall purpose of the four research studies contained within this thesis was to determine the influence of post-exercise CWI on muscle metabolic activity, acute and long-term adaptations to exercise and exercise training, respectively. The first two studies of this thesis were designed to determine the reliability and between limb differences of the near infrared spectroscopy (NIRS)-derived indices describing muscle oxygenation and metabolic activity. Such information was necessary to substantiate the use of NIRS to monitor muscle aerobic adaptations to training/cooling as well as the onelegged cooling model utilised throughout this thesis. In study 1, it was found that there were considerable differences in reliability levels with regards to the analytical technique chosen. However the variables demonstrated CVs ranging from 3 to 35%, which is lower than currently reported changes in training-induced adaptations and/or group differences between athletes and sedentary controls (23% - 450%). In study 2, it was shown that there were no between limb differences in NIRS-derived variables. As such, studies 1 and 2 indicate that changes in NIRS-derived variables are suitable indices to monitor the influence of cooling on training-induced adaptations in the muscle, as well as substantiate that the exercise/training protocols induced similar physiological stimulus in both the intervention and control limbs. In study 2, it was also shown that cooling one leg (15 min at 10°C) from the gluteal fold downwards resulted in significant decreases in post-exercise vastus lateralis skin temperature (35.1 ± 0.6 vs. 16.9 ± 1.7°C, p < 0.001), microvascular perfusion (20 ± 4%, p < 0.01) and muscle metabolic activity (p < 0.05) while not resulting in shivering thermogenesis. While these responses may improve local muscle recovery, its simultaneous effect is on muscle aerobic adaptations are unclear. Indeed, reduced muscle metabolism might attenuate mitochondrial biogenesis via inhibiting AMPK activation or via a decrease in the Q10 effect. Conversely, cooling in cell and rodent models has been shown to up-regulate the expression of the transcriptional coactivator PGC-1α, which is implicated in the regulation of non=shivering thermogenesis. As such, studies 3 and 4 investigated the acute and chronic influence of post-exercise cooling on muscle aerobic adaptations to exercise and exercise training, respectively. In study 3, it was shown that cooling resulted in significantly lowered intramuscular temperatures (28.9 ± 2.3°C vs. 37.0 ± 0.8°C, p < 0.001). This change was associated with a significant increase in the mRNA content of PGC-1α in the cooled limb compared with control. However, associated PGC-1α targets related to vascular and metabolic adaptation, namely VEGF and nNOS, only demonstrated significant changes from baseline (i.e. time effects) with no significant differences between conditions evident. These data indicate that an acute post-exercise cooling intervention enhances the gene expression of PGC-1α and therefore may provide a valuable strategy to enhance exercise-induced mitochondrial biogenesis. However its influence on VEGF and nNOS expression and associated functional adaptations warrants further research. In study 4, we investigated the effect of regular post-exercise CWI on training induced AMPK activity and mitochondrial biogenesis. Ten males performed 3 sessions∙wk-1of endurance training for 4 wks, where following each session subjects immersed one leg in a cold water bath (10°C) to the level of their gluteal fold for 15 min, while the contra-lateral leg served as control. Subjects’ maximal oxygen consumption and maximal aerobic running speed were improved by 5.4% and 6.4% following training (p < 0.05). Additionally, regular post-exercise cooling enhanced exercise-induced increases in basal AMPK activity. Despite an increase in AMPK activity, a concomitant increase in downstream targets PGC-1α and most mitochondrial electron chain subunits was not observed. However, a significant increase in COX3 protein content was evident and hence indicates that mitochondrial biogenesis may be enhanced. Regardless, we advocate caution with regards to regular use of this intervention as cold-induced mitochondrial biogenesis may concomitantly decrease mitochondrial efficiency. Further research should focus on muscle aerobic function following regular CWI also verify if increases in AMPK activity observed in this study translates to improved glucose disposal and fatty acid oxidation.

Projeto de Graduação apresentado à Universidade Fernando Pessoa como parte dos requisitos para obtenção do grau de Licenciada em Fisioterapia
Introdução: a crioterapia, nas suas diversas formas de aplicação, é uma modalidade frequentemente utilizada em ambientes clínicos e desportivos para o tratamento de lesões músculo-esqueléticas, tanto na fase aguda como durante a reabilitação. Objetivo: avaliar os efeitos da utilização da imersão em água fria e da câmara de crioterapia pós esforço, em indivíduos saudáveis ativos e/ou em desportistas.Metodologia: a pesquisa foi realizada na base de dados Pubmed, fundamentada com artigos recentes, avaliados segundo a escala Critical Appraisal Skills Programme (CASP). Resultados: Nesta revisão foram incluídos 7 estudos, com um total de 164 atletas de ambos os sexos, e com idade entre 18 e 35 anos. Após a utilização destas técnicas de crioterapia, pode-se observar redução de temperatura no músculo e no corpo, sendo mais acentuada com a câmara de crioterapia, e benefícios na recuperação muscular, perceção de dor, sensação de desconforto ou no bem-estar. A imersão em água fria, apesar de não interferir com o equilíbrio nem com o tempo de reação, dificulta a perceção posicional.Conclusão: ambas as técnicas evidenciam benefícios na recuperação muscular pós esforço, embora com certas especificidades nos seus efeitos.
Introduction: Cryotherapy, in its various forms of application, is a modality frequently used in clinical and sports environments for the treatment of musculoskeletal injuries, both acute and during rehabilitation. Objective: to evaluate the effects of the use of cold water immersion and post-effort cryotherapy chamber in active healthy individuals and / or sportsmen. Methodology: the research was carried out in the Pubmed database, based on recent articles evaluated according to scale Critical Appraisal Skills Program (CASP). Results: In this review, 7 studies were included, with a total of 164 athletes of both sexes, and aged between 18 and 35 years. After using these cryotherapy techniques, it can be observed a reduction in temperature in the muscle and in the body, being more accentuated with the cryotherapy chamber, and benefits in muscle recovery, pain perception, discomfort sensation or well-being. The immersion in cold water, although not interfering with the balance nor with the reaction time, hinders the positional perception. Conclusion: both techniques show benefits in muscle recovery after exertion, although with certain specificities in their effects.
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Après une compétition, certains sportifs utilisent des stratégies pour accélérer la récupération des dommages musculaires. Le but général de cette thèse était d’étudier les effets de différentes stratégies sur les cinétiques de récupération après un exercice inducteur de dommages musculaires. Les objectifs des études réalisées étaient : 1) de comparer les effets du bain froid (10 minutes à 10°C) et de la cryothérapie corps entier (3 minutes à -110°C) sur la récupération ; 2) d’évaluer les effets d’une séance de musculation du haut du corps réalisée le lendemain d’un exercice des membres inférieurs sur leur récupération; 3) d’étudier les effets de la consommation d’un placebo en comparaison avec une condition contrôle sur les cinétiques de récupération. Le modèle expérimental utilisé pour induire des dommages musculaires dans ces trois études était un exercice constitué de 5 séries de 15 contractions excentriques maximales des fléchisseurs du genou. Cet exercice était caractérisé par une baisse de la fonction musculaire, une augmentation des concentrations sanguines en créatine kinase et une augmentation des douleurs musculaires. La fonction musculaire, des marqueurs perceptifs et sanguins des dommages musculaires étaient également évalués au cours des 72h suivant cet exercice. Dans la première étude, le bain froid permettait d’accélérer la récupération de la performance lors d’un saut en contre-mouvement sur une jambe et sur deux jambes 72h après l’exercice en comparaison avec la cryothérapie corps entier. Dans la deuxième étude, la musculation du haut du corps n’avait pas d’effet délétère sur la récupération et avait un effet bénéfique modéré sur la récupération de la force concentrique 48h après l’exercice. Dans la troisième étude, la consommation d’un placebo présentait une très forte probabilité d’avoir un effet bénéfique sur la performance en saut et les douleurs musculaires 72h après exercice. La perception de la récupération était également modérément améliorée 72h après exercice. En conclusion, les trois stratégies de récupération utilisées lors de ces études à savoir le bain froid, la séance de musculation et la consommation d’un placebo peuvent être efficaces après des exercices induisant des dommages musculaires
Following competition, athletes commonly use strategies to accelerate their recovery from muscle damage. The overall objective of this thesis was to study the effects of different recovery strategies on recovery kinetics following exercise-induced muscle damage. The aims of the studies were as follows: 1) to compare the effects of cold-water immersion (10 minutes at 10°C) and whole-body cryotherapy (3 minutes at -110°C), 2) to assess the effects of an upper-limb strength training session, performed the day after a lower-limb exercise,, 3) to study the effects of a placebo ingestion in comparison with a passive recovery. The experimental model used to induce muscle damage in these three studies consisted of 5 sets x 15 repetitions of maximal eccentric contractions of the knee flexors muscles. This exercise resulted in a decrease of muscle function, increases in blood creatine kinase concentration as well as increases in perceived muscle soreness. Muscle function blood markers and subjective recovery from muscle damage were assessed throughout a 72h period post exercise. In the first study, cold-water immersion was more effective than whole-body cryotherapy evidenced through an accelerated recovery of both single and double leg countermovement jump 72h following exercise. In the second study, the upper-limb strength training session had a moderate beneficial effect on concentric force recovery 48h after the exercise and both interestingly and importantly, did not have any detrimental effect on recovery. Finally for the third study, placebo ingestion was ‘very likely’ to have a beneficial effect on jump performance and muscle soreness 72h post-exercise. Additionally, perceived recovery was moderately better 72h following exercise. In conclusion, the studies conducted in this thesis showed that the recovery strategies of cold-water immersion, strength training and ingestion of a placebo, may be effective after exercise-induced muscle damage

(Cf. corpus p. 25-26) Ce travail de thèse s'est articulé autour de deux problématiques : les réponses cardiovasculaires consécutives à l/ différents protocoles d'exercice et 2/ différents protocoles de récupération. Concernant la première, 3 protocoles de recherches ont été menés. L'un avait pour objectif de déterminer les effets aigus d'exercices de même durée proposant une quantité de travail totale équivalente distribuée de façon constante (CC) ou intermittente (IT), sur la rigidité artérielle multi-segmentaire et ses déterminants. Les deux autres se proposaient d'explorer les dysfonctions cardiaques induites par des exercices de durées plus longues (2 à 4 heures) et leurs mécanismes sous-jacents. La seconde problématique de ce travail de doctorat a conduit à la réalisation de 5 protocoles de recherche. L'immersion contrastée (alternance d'immersions d'une à deux minutes jusqu'à l'aine à ~ 12°C et à ~ 36°C), l'immersion en eau froide (~ 12°C) et la compression élastique ont été tout particulièrement étudiées. Les points suivants ont été abordés : la comparaison des effets de la compression élastique et de l'immersion contrastée sur la performance subséquente ; la connaissance des facteurs concourant aux bénéfices de ces dernières entre des efforts intenses et brefs (c.-à-d. étude du débit sanguin musculaire, de la saturation tissulaire en oxygène, de la clairance des métabolites, etc.) ; l'étude des effets de la pression hydrostatique seule (immersion à neutralité thermique ), et ceux de celle-ci associée au froid (immersion en eau froide ) ou à l'alternance de température (immersion contrastée) sur le débit sanguin musculaire; et enfin l'étude des effets sur certains paramètres de la récupération du port d'une compression élastique au cours et au décours d'un trail. Dans ce contexte, les résultats de nos études mettent en évidence qu'un exercice de type IT diminue davantage la rigidité artérielle multi-segmentaire qu'un exercice de type CC. Cette diminution plus prononcée est associée à un relargage plus important de substances vasodilatatrices (NO,ANP, lactates, etc.). Nous avons également montré qu'un exercice prolongé de durée modérée engendre des dysfonctions cardiaques transitoires. Plus particulièrement, certains indices de contractilité évalués par une technique échocardiographique de dernière génération (c.-à-d. le « Speckle Tracking Echocardiography ») nous ont permis de mettre en évidence que la baisse de la fonction systolique du ventricule gauche (VG) était associée à une atteinte contractile du myocarde dans des conditions standardisées de fréquence et de charge cardiaques. Nos résultats soulignent également le rôle clé de la torsion ventriculaire dans la diminution du remplissage du VG et par conséquent de la fonction diastolique à l'arrêt de l'effort. Les études expérimentales s'intéressant aux techniques de récupération post-exercice indiquent que l'immersion contrastée et la compression élastique par rapport à une récupération passive, lorsqu'elles sont appliquées immédiatement après un premier exercice fatiguant, améliorent la performance subséquente (exercice de pédalage de 5 min) lorsque celle-ci est répétée dans un laps de temps court (15 min). De plus, l'immersion contrastée est plus efficace que la compression élastique pour améliorer la performance subséquente. Ces techniques de récupération accélèrent la clairance du lactate, cette dernière étant accélérée davantage après l'immersion contractée. La compression élastique augmente le débit sanguin musculaire mais également la saturation tissulaire en oxygène, que ce soit avant et après l'effort. Par rapport à une récupération passive, l'immersion contrastée augmente également le débit sanguin musculaire après l'effort, et davantage que la compression élastique. (...)
(Cf. corpus p. 27-28) This thesis work focuses on the cardiovascular responses consecutive to l/ various exercice modalities and 2/ various post-exercise recovery interventions. With regard to the exercise modalities, 3 experimental protocols were led. The first one aimed to compare the acute effects of constant and interval exercises on regional arterial stiffness and these determinants. Two others studies focused on the cardiac dysfunctions induced by exercises of longer durations (2-3h) and the underlying mechanisms. The second problematic of this thesis work led to 5 studies. The following questions were approached: the comparison of the effects of contrast water therapy and compression stockings on the subsequent performance; the knowledge of the factors at the origin of the benefits of these recovery interventions between repeated brief and exhaustive bouts of physical exercise (i.e. muscle blood flow, muscle oxygenation, removal of metabolic waste, etc.) ; the changes in leg muscle blood flow, caused by hydrostatic pressure alone [thermoneutral water immersion), and in addition to cooling (cold water immersion) or alternating of temperature (contrast water therapy); and finally the effects of elastic compression worn during and after a trail running race on the participants' recovery. Our results show that interval exercise decreases more regional arterial stiffness [central and peripheral) than constant exercise. This more pronounced decrease is associated with a higher concentration of vasodilator factors (NO, ANP, lactates, etc.). We also show that a prolonged exercise (2-3h) induce transient cardiac dysfunctions. Specifically, parameters of systolic function evaluated using 2D-speckle tracking echocardiography not only at rest, but also during incremental tests to adjust heart rate demonstrate that the 3h-period of prolonged and strenuous exercise induces left ventricular systolic dysfunction. Our results also demonstrate that depressed diastolic function is associated with delayed untwisting velocity. The studies focusing on post-exercise recovery interventions indicate that compared with passive recovery, contrast water therapy and compression stockings improve the subsequent 5-min maximal performance in cycling when this one is repeated during a brief elapsed time (i.e. 15 min). Moreover, contrast water therapy is more efficient than compression stockings to improve the subsequent performance. Theses recovery interventions accelerate the removal of lactates, and contrast water therapy more than compression stockings. The elastic compression increases muscle blood flow but also tissue oxygen saturation, before and after a physical exercise. Contrast water therapy also increases muscle blood flow after an exercise compared with a passive recovery, and more than elastic compression. (...)

L’impact de l’exposition au froid dans le contexte de l’exercice physique et de la récupération sur des variables physiologiques et perceptives a été investigué.Nous avons mis en évidence, par méta-analyse, que : - L’exposition au froid lors de l’activité physique permet une amélioration de la performance pour des exercices de type aérobies et anaérobies (taille de l’effet variant suivant la technologie de refroidissement utilisée et la partie du corps refroidie).- La cryothérapie/cryostimulation et l’immersion en eau froide utilisées à la suite d’une activité physique permet une réduction des courbatures, de la fatigue perçue et des concentrations sanguines de marqueurs de dommages musculaires et de l’inflammation.Nos travaux expérimentaux montrent que :- Le port d’un gilet refroidissant lors d’une activité physique éprouvante améliore les réponses perceptives de confort thermique, d’humidité et de bien-être et réduit le stress physiologique (température cutanée diminuée, retour plus rapide à la fréquence cardiaque de base, amélioration de l’oxygénation cérébrale).- 3 min d'exposition en cryothérapie corps partiel est une durée optimale pour améliorer la qualité de sommeil après un entraînement.- 3 min d’exposition en cryothérapie corps entier améliore la qualité subjective (questionnaires) et objective du sommeil (actimétrie). Les mécanismes liés à cette amélioration dépendent de l’activité du système parasympathique lors des phases de sommeil profond.Ce travail montre l’efficacité de l’utilisation du froid dans différents contextes de l’activité physique et dans les processus de récupération. Les mécanismes biologiques susceptibles d'interagir dans ces processus de récupération sont présentés
The impact of cold exposure in the context of physical exercise and recovery on physiological and perceptual variables was investigated.We have highlighted, by meta-analysis, that:- Exposure to cold during physical activity improves aerobic and anaerobic physical performance (effect sizes depending on the cooling technique and the cooled body area).- Using cryotherapy / cryostimulation and cold-water immersion following a physical activity reduces muscle soreness, perceived fatigue and blood concentrations of muscle damage and inflammatory markers.Our experimental work shows that:- Wearing a cooling vest during a vigorous physical exercise improves perceptual responses such as thermal comfort and reduces physiological stress (reduced cutaneous temperature, faster return to resting heart rate, improvement of the cerebral oxygenation).- A 3-min partial body cryotherapy exposure is an optimal time to improve the quality of sleep after training.- A 3-min whole body cryotherapy exposure improves the subjective (questionnaires) and objective (actimetry) sleep quality. The mechanisms related to this improvement seems to depend on the parasympathetic activity during deep sleep episodes.This work shows the effectiveness of the cooling uses in different contexts of physical activity and recovery processes. The biological mechanisms likely to interact in these recovery processes are presented

The hand has the highest surface area-to-volume ratio of any body part. This property offers the potential for the hand to serve an important function in thermoregulation through radiative heat loss. Theoretically, the capacity for heat loss may be influenced by hand and digit proportions, but the extent to which these proportions influence the hand's radiative properties remains under-investigated. Although hand morphology is highly constrained by both integration and functional dexterity, phenotypic variation in hand and digit proportions across human populations shows broad ecogeographic patterns. These patterns have been associated with climate adaptation. However, the theory linking climate adaptation to such ecogeographic patterns is based on underlying assumptions relating to thermodynamic principles, which have not been tested in vivo. This study sought to determine the influence of hand and digit proportions on heat loss from the hands directly, the additional anthropometric factors that may affect this relationship, and the impact of variation in hand proportions on dexterity in the cold. The relationship between hand proportions and thermoregulation was tested through both laboratory-based investigation and a field study. The laboratory investigation assessed the relationship between hand proportions and heat loss, the influence of body size and composition on this relationship, and the effect of morphological variation on manual dexterity. Participants (N=114; 18-50 years of age), underwent a 3-minute ice-water hand-immersion. Thermal imaging analysis was used to quantify heat loss. Hand and digit proportions were quantified using 2D and 3D scanning techniques; body size and composition were measured using established anthropometric methods and bio-impedance analysis. After accounting for body size, hand width, digit-to-palm length ratio, and skeletal muscle mass were significant predictors of heat loss from the hand, whilsthand length and fat mass were not. A separate set of participants (N=40) performed a Purdue pegboard dexterity test before and after the immersion test, which demonstrated that digit width alone negatively correlated with dexterity. The field study tested whether phenotypic variation in upper limb proportions could be attributed to cold adaptation or selection for dexterity in living populations exposed to significant energetic stress. Upper limb segment lengths were obtained from participants (N=254; 18-59 years of age), from highland and lowland regions of the Nepalese Himalayas using established anthropometric methods, and relative hand proportions were assessed in relation to severe energetic stress associated with life at high altitude. Relative to height, hand length and hand width were not reduced with altitude stress, whilst ulna length was. This indicates that cold adaptation is not shaping hand proportions in this case, although phenotypic variation in other limb segments may be attributed to cold adaptation or a thrifty phenotype mechanism. The current study provides empirical evidence to support the link between surface area-to-volume ratio, thermodynamic principles and ecogeographical patterns in human hand morphology. However, this research also demonstrates the complexity of the hand's role in thermoregulation; not only do other factors such as muscularity affect heat loss from the hand, but hand morphology is also highly constrained by integration and dexterity.

Intense exercise is known to cause alterations in the psychophysiological status of an athlete. Monitoring the health and recovery of an athlete is imperative for the maintenance of performance and reduced fatigue and injury incidence. The physicality associated with select sports results in significant elevations and suppression of psychophysiological biomarkers that are often modulated by game-related impacts, intense training regimes and psychosocial aspects associated with the professional era. The aim of the studies outlined in this thesis were to determine the effectiveness of selected “stress” markers in several sports that result in significant “stress”, and quantify the level of acute and chronic “stress” following individual games and competitions to improve athlete management and recovery. Study one aimed at developing a new strong-cation exchange high performance liquid chromatography (SCX-HPLC) method for the detection and quantification of urinary pterins and creatinine in a body-building cohort completing high intensity resistance training. The method had an intra- and inter-assay variability of 3.04 % and 5.42 % respectively, with visibly clear peaks and no tailing. Urinary neopterin (NP) and 7,8-dihydroneopterin during a week of competitive natural body-building did not significantly change indicating no alteration in immune system function and oxidative stress. It did provide evidence for the use of specific gravity as a similarly reliable method for urine volume correction following exercise. Study two focused on a playoff game of elite amateur rugby. The time course changes of NP, cortisol, salivary immunoglobulin A (sIgA) and myoglobin in 11 elite amateur rugby players were measured up to 86 hours post-game. Cortisol increased 4-fold, myoglobin 2.85-fold, NP 1.75-fold and total NP 2.3-fold, all significant, whilst sIgA did not change. All markers returned to baseline within 17 hours providing valuable information for sample collection schedule optimization. Respiratory elastance was also measured by ventilation for the assessment of exercise induced lung inflammation/injury following the game (Chapter three). There was an increase in elastance in selected individuals that did not correlate with either global positioning system (GPS) or impact data. It was shown however, that a ventilator is capable of measuring respiratory changes in a conscious and healthy individual. Study three focused on the final three games of professional rugby in the 2013 ITM Cup. The acute and cumulative changes in the same four markers were analysed following three home games. There were significant increases in NP, total NP, cortisol and myoglobin along with significant suppression of sIgA (p < 0.05). Large intra- and inter-individual variation existed between players with changes associated with total impacts. Moreover, impact induced muscle damage may account for changes in oxidative status. Specific gravity (SG) was shown to be a more reliable marker for urine volume correction in comparison to creatinine; while some players showed signs of cumulative stress. Study four examined stress in a professional team throughout the 22 week 2014 Super 15 competition. Part one investigated changes in oxidative stress and muscle damage markers to solidify the muscle damage/oxidative status theory postulated in the previous study. Experimental evidence showed iron and myoglobin are separately capable of oxidizing 7,8-dihydroneopterin to NP in vitro. It was then identified that players who suffered the greatest muscle damage as a result of impacts also had the greatest change in oxidative status (NP). This evidence suggests rugby union induces significant alterations in oxidative status that may be exacerbated by the impact induced release of myoglobin. Part two measured urinary NT-proBNP during the last two consecutive home games to identify whether rugby union causes significant cardiovascular stress and if the pre to post-game change can be explained by GPS technology. Significant individualized elevations were observed in games one and two which did not correlate with any GPS measurements or impacts. Concentrations returned to normal ~ 36 hours post-game suggesting no permanent damage to cardiac muscle had occurred. The lack of correlation suggests GPS technology is not an accurate measure of cardiovascular stress in professional rugby union. Part three involved the measurement of cortisol, total NP and sIgA throughout the season to assess the degree of cumulative stress. Samples were taken at regular intervals ~ 36 hours post-game for 22 weeks. Extreme inter-individual variation was present. Select individuals showed continual elevation in immune system activation and psychophysiological stress, whilst others presented with a continual decline in immune system function. Collectively however, minor deviations from baseline in all markers were observed and participation in long distance travel did not significantly affect the psychophysiological status of the group. Together this suggests a season does not cause an accumulation in psychophysiological stress, although careful individual player analysis is warranted. Understanding rugby union positional demands is essential for training program specification and position specific development of players. Part four used GPS, video-analysis and biochemical analysis to identify positional demands in five regular season games. Forwards tended to be involved in more impacts and covered less distance, while backs covered more distance and carried the ball into contact more regularly. There was no difference in the psychophysiological status between positions indicating both aspects of stress (impacts and distance covered) may induce a similar response. Alternatively, individual biological variation may be solely responsible for this change suggesting careful consideration should be given when using traditional work-load measures such as GPS when quantifying “stress”. Part five assessed the effectiveness of varied recovery interventions. Total NP, cortisol, myoglobin and sIgA were measured pre- post- and ~ 36 hours post game to identify which intervention was most effective at returning players to a psychophysiological state that allowed for the resumption of normal training. Findings concluded the immediate post-game strategy employed by the team (cold bath, consumption of protein and carbohydrates, compression garments and eight hours sleep) seemed to provide the greatest psychophysiological improvement regardless of the “next-day” intervention. There was large inter-individual variation and players were still in a state of recovery ~ 36 hours post-game as indicated by the elevated total NP and sIgA concentrations. Study five had four aspects. Develop a new, cost-effective and simple reverse phase HPLC (RP-HPLC) method for the quantification of urinary myoglobin in a clinically relevant range, quantify the level of structural stress following a simulated mixed martial arts (MMA) contest, determine whether cold water immersion attenuates the level of inflammation and muscle damage following a contest, and whether this hypothesized attenuation may be explained by cryotherapy induced mononuclear cell activation suppression in vitro. The RP-HPLC method had an intra- and inter-assay variations from 0.32 - 2.94 %. Linearity was in the range of 5 – 1000 µg/mL which detected significant increases in urinary myoglobin following the MMA contest. Total NP was found to significantly increase following the contest and return to approximately pre-contest levels 24 hours later for the passive group only. Cold water immersion was further found to attenuate the total NP increase in the first two hours post-contest solidifying its use as a recovery technique following intense exercise, while cryotherapy significantly suppressed T-cell activation. This study provides a reliable and repeatable assay for muscle damage quantification in a clinically relevant range, evidence of the physicality associated with MMA, and indicates cold water immersion is a reliable recovery intervention that may impart its positive benefits through T-cell suppression. The data generated by these investigations highlights the necessity for individual physiological analysis. Group data often masks the extreme variation that exists in clinical and exercise trials where treatment and management of athletes is conducted for recovery and performance. Biochemical analysis provides an added sophistication of work-load and psychophysiological assessment that common technological methods cannot emulate. With a lack of correlation between the quantitative changes in specific non-overlapping biomarkers and GPS, video-analysis and questionnaires, it would seem pertinent to develop a non-invasive quantitative approach in elite sport to understand the level of exercise-induced psychophysiological stress for the precise management of athletes.

碩士
國防醫學院
生理學研究所
100
Cold-induced vasodilatation (CIVD) occurs 5-10 minutes after cold induced vasoconstriction (CIVC) when exposure to cold environments. It is believed to reduce the risk of cold injuries. CIVD is followed by a new phase of vasoconstriction. This phenomenon was called Lewis reaction. However, the mechanism of Lewis reaction is still debated. The aim of present study is to investigate the role of sympathetic nerve modulation, nitric oxide (NO) and axon reflex in Lewis reaction by using spectral analysis of cardiovascular variability. Rats were placed into 2 cm iced water and standing for 10 minutes. Blood pressure and ECG were continuously recorded for three 10-min periods during the cooling impact procedure. Then we acquire very low (VLF: 0.02-0.2 Hz) frequency fluctuations of cardiovascular variability which primarily reflected myogenic vascular function. The VLF fluctuation was reduced during cooling impact, which reflected myogenic vascular relaxation. And there is a correlation between myogenic vascular function and sympathetic influence during CIVD and CIVD. With Guanethidine administered, which cause postganglionic noradrenergic blockade, the VLF fluctuation was increased during CIVD. However, the VLF fluctuation was decreased when α2 adrenergic receptor inhibition with Yohimbine. In addition, Inhibition of nitric oxide synthesis with L-NAME increased VLF fluctuation during CIVD. The concentration of nitric oxide metabolites nitrate (NO3-) and nitrite (NO2-) was increased after cooling impact. Therefore, we conclude that sympathetic outflow is involved in CIVC and CIVD mechanism, while nitric oxide plays an important role in the CIVD occurrences.

博士
國立體育大學
競技與教練科學研究所
104
Background: Cold water immersion (CWI) is one of popular recovery treatment methods following competition and training program. Bleakley et al. (2012) reported that CWI could be attenuated the extent of exercise-induced delayed onset muscle soreness (DOMS), and accelerated the recovery of fatigue. Hydrostatic pressure and cold stimulus could be induced blood redistribution and thermoregulation when body immersed in cold water. The different depths of CWI would be induced different hydrostatic pressures and would be possibly resulted in different extent of physiology responses, but it is not known whether the different extents of hydrostatic pressures and physiology responses induced by the different depths of CWI would be enhanced the recovery from exercise-induced DOMS? Purposes: 1) To compare two different depths of cold water immersion, between CWI to waist (CWI-W) and chest (CWI-C), for changes in cardiovascular load, thermal and muscle oxygenation before, during and after CWI; 2) To compare the effects of two depths of CWI interventions (CWI-W, CWI-C) and a passive recovery (control condition) after plyometric exercise on the recovery of muscle soreness. Methods: Study 1: Ten health young men were recruited for this repeated measures and crossover design study. Each subject performed CWI-W and CWI-C, respectively, for 15 consecutive minutes separated by 2 days apart. Heart rate (HR), mean arterial pressure (MAP), mean skin, core and body temperature, rating of perceived cold, and muscle oxygen saturation of the vastus lateralis were measured before, during CWI and post-CWI for 60 consecutive minutes. Data were analyzed by a two-way design of analysis of variance. Study 2: Thirty health young men were recruited for this study, and then were randomly assigned into CWI to waist (CWI-W, n = 10), CWI to chest (CWI-C, n = 10) or passive recovery (CON, n = 10) group based on pre-test maximal isometric strength (MVC) at knee extensors. Each subject performed 100 (5 sets of 20 repetitions) drop jumps (DJ) from a high of 0.6 m box with 2 min rest between sets. The DJ exercise was followed by either passive recovery (CON), or cold water immersion (14.5°C: CWI-W, CWI-C) for 15 min at 30-min, 24.5, 48.5 and 72.5 hours post DJ exercise. Muscle passive stiffness (MPS), muscle soreness (SOR), MVC torque, counter movement jump (CMJ) and squat jump (SJ) height were measured before, immediately and 1-4 days after DJ exercise. SOR was repeatedly measured at 5-min post recovery intervention at 1-3 days after DJ for 3 groups. Changes in variables after exercise were compared between the groups by two-way repeated measures ANOVA. Results: Study 1: HR and MAP significantly increased at the initial stage of immersed at two depths CWI, but there were no significant differences between two depths CWI at the immersion and recovery period (p > .05). No significant differences in mean skin, core and body temperature between two depths CWI during 15-min immersed, but significantly lower in core and body temperature in CWI-C than CWI-W at the recovery period. Total haemoglobin (THb), oxygenated haemoglobin (O2Hb) and tissue saturation index (TSI) were significantly lower than pre-CWI at 5-min recovery period in both CWI-W and CWI-C, especially TSI was significantly lower than CWI-W (p < .05). Study 2: HR and core temperature increased following DJ exercise, but no significant differences between 3 groups (p > .05). Mean skin and body temperature were significantly lower in CWI-W and CWI-C groups than CON during immersion and recovery period. Core temperature was only significantly lower in CWI-C compared with CON at 50 to 60 min during the recovery period. THb and O2Hb were significantly lower in CWI-W and CWI-C compared with CON at 5 to 60 min during the recovery period, and TSI was also significantly lower in CWI-W and CWI-C compared with CON at 5 to 25 min in recovery period；however, there were no difference between CWI-W and CWI-C during the recovery period (p > .05). SOR increased and MPS, MV, CMJ and SJ height significantly decreased following DJ exercise, these markers did not return to baseline at 4 days after DJ exercise except for MPS, and the extent of recovery between the 3 groups was no significantly difference (p < .05). SOR decreased immediately after CWI intervention at 24.5 and 48.5 hour after DJ exercise in CWI-W and CWI-C groups (p < .05). Conclusion: Cardiovascular load did not increase regardless of the depths of CWI below the level of heart. Both two depths of CWI significantly decreased skin, core and body temperatures as well as the muscle blood flow after DJ exercise. Although CWI has the acute positive effect on decreasing the extent of muscle soreness compared with passive recovery, these results show that the changes in muscle soreness and indirect muscle damage markers after plyometric exercise were not affected by CWI regardless of the water depth. It is concluded that the different depths of CWI interventions did not efficiently enhanced recovery from exercise-induced DOMS. This finding may have provided some reference to athletic trainers and coaches when using the different depths of CWI for different physiology responses and for the effects of recovery on muscle damage and DOMS.

Cold-water immersion (CWI) is a common recovery modality used to facilitate restoration of pre-exercise muscle force generation and soreness following high-intensity exercise. Although it is commonly used by athletes and commonly studied in sport science, evidence is equivocal regarding its efficacy. We compared 4 CWI protocols (10 or 30 minutes at 10 or 20°C) of different durations and temperatures with passive rest for their effects on drop jump and squat jump height, inflammation (IL-6, IL-10, IL-8, MPO, IL-1β, TNFα, IFNγ, GM-CSF, IL-2), and ratings of soreness/impairment following high-intensity intermittent sprint-exercise. CWI for 10 minutes at 10°C promoted restoration of force generation, while CWI for 30 minutes at 10°C was associated with lower ratings of soreness/impairment, but higher plasma IL-8 and MPO at 2 hours post-exercise. Overall, minor functional benefits of CWI for 10 minutes at 10°C were observed, while longer duration CWI protocols may increase post-exercise inflammation.

Rugby union training and match-play are physiologically and psychologically very demanding and the execution of post-exercise recovery techniques in players‟ training regimes are therefore necessary to aid in the physiological and psychological restoration of athletes‟ training and performance abilities. However, despite numerous research findings with regard to the efficiency of especially cold water immersion (CWI), contrast water therapy (CWT) and passive recovery (PAR) on the physiological recovery of athletes post-exercise, only a limited number of researchers have examined the possible benefits of these recovery techniques on the psychological recovery of athletes. Consequently, the objectives of this study were firstly to determine the difference between the acute effects of CWI and PAR on the mood states (anger, confusion, depression, fatigue, tension and vigour) and the energy index of university-level rugby players post-exercise, and secondly to determine the difference between the acute effects of CWT and PAR on the mood states and the energy index of university-level rugby players post-exercise. Twenty-three under/21 university-level rugby players (age 20.1 ± 0.41) of a South African university club voluntarily participated in this study. The players were randomly divided into a control group (PAR) and an experimental group (CWI or CWT). Participants completed the Stellenbosch Mood Scale (STEMS) questionnaire over four time periods: during the morning (baseline); before completion of a high-intensity anaerobic training session (pre-anaerobic); after completion of a high-intensity anaerobic training session of 15 minutes (post-anaerobic) and after completion of a 20-minute recovery session (post-recovery). Blood lactate measurements were also taken 3 minutes after completion of the anaerobic session. To test the first objective, the experimental group completed 20 minutes of CWI, whereas the control group recovered passively for the same time period. For the purpose of the second objective, the experimental group completed 20 minutes of CWT, whereas the control group recovered passively for the same time period. Although the dependent t-test and effect size results of the first study showed that the experimental group (CWI) experienced no significant changes from the pre-anaerobic to post-recovery time periods for any of the STEMS subscale values or the energy index, the control group‟s (PAR) confusion, depression and tension subscale values decreased significantly (p < 0.05) from the pre-anaerobic to the post-recovery time periods. Despite these changes, the one-way between groups‟ analysis of covariance (ANCOVA) revealed no significant differences, except for the vigour subscale, which obtained a medium practical significant increase [Effect size (ES) = 0.65)] for the experimental compared to the control group when the pre-anaerobic and post-recovery changes in the STEMS subscale and energy index values between groups were compared. The dependent t-test and effect size results of the second study indicated that neither the experimental (CWT) nor the control group (PAR) experienced significant changes from pre-anaerobic to post-recovery time periods for any of the STEMS subscale or energy index values. However, the ANCOVA revealed that the experimental group showed a statistically significant higher value for the vigour subscale (p = 0.05) when compared to the control group. In addition, for vigour, the experimental group recorded a large practically significant higher value (ES = 0.92) for vigour as well as a large practically significant lower value for fatigue (ES = 0.88) compared to the control group. To the researchers‟ knowledge, this was the first study to compare the efficacy of CWI, CWT and PAR on the recovery of athletes‟ STEMS-derived mood states. Previous studies mainly focused on perceived fatigue, muscle soreness, Profile of Mood States- (POMS-) derived mood states and rate of perceived exertion (RPE) when investigating psychological recovery in athletes. However, despite the uniqueness of this study, results showed that when compared to PAR, CWI and CWT did not aid more in the acute psychological recovery of university-level rugby players‟ mood states. Vigour was the only mood state subscale for which both the CWI and CWT groups showed a practical or statistically significant higher value compared to the PAR group, while fatigue obtained a higher practical significant value for only CWT when compared to PAR. Therefore, although the study results support the use of CWI and CWT to alleviate vigour and fatigue post-exercise when compared to PAR, further research is required to gain understanding into the psychological mechanisms of both CWT and PAR, with an emphasis on knowledge and information in recovery of mood disturbances after exercise.
MSc (Sport Science), North-West University, Potchefstroom Campus, 2015

Despite a lack of understanding of the underlying mechanisms, cold-water immersion (CWI) is extensively used by athletes for recovery. Previous evidence demonstrates its effectiveness in reducing muscle soreness, with the effects on muscle function unclear (260). Given the subjective nature of soreness, the efficacy of post-exercise CWI may be confounded by a potential placebo effect. Debate also exists surrounding the merit of CWI in athletic training regimes. While better recovery may improve subsequent training quality and stimulus (490), there is suggestion that CWI may attenuate long-term skeletal muscle adaptations (523). Conversely, CWI may stimulate the expression of genes key to mitochondrial biogenesis (192). To fully understand the mechanisms underlying CWI, and its influence on athletic performance, it is crucial to investigate these issues further. This thesis firstly aimed to investigate if the placebo effect is responsible for any short-term performance or psychological benefits following post-exercise CWI. To assess this, CWI was compared with a placebo and thermo-neutral control condition in the recovery from a single bout of high-intensity interval training (HIT). A recovery placebo was shown to be superior in the recovery of muscle strength over 48 h as compared with a control, and as effective as CWI, attributed to improved psychological ratings of well-being. This suggests that the placebo effect may account for some of the observed benefits following CWI, or alternately, that it is as strong as the commonly-hypothesised physiological benefits. For the remaining studies, this thesis aimed to investigate the underlying molecular mechanisms by which CWI may alter cellular signalling and the long-term adaptive response to HIT in human skeletal muscle. It was demonstrated that CWI augments the post-exercise response of a number of signalling proteins and genes associated with mitochondrial adaptations. The oxidative stress imposed by CWI may serve to augment p53 activation post-exercise, leading to a greater up-regulation of its downstream targets. However, despite these alterations in cellular signalling, regular post-exercise CWI did not promote an improved adaptive response to HIT, as measured by markers of mitochondrial biogenesis and other aerobic adaptations.

Rugby has become a popular team sport worldwide with players training harder and competing more frequently, placing a great physiological demand on their bodies. To retain this performance level, players need to recover sufficiently between training and competitions. Two popular recovery techniques used are cold water immersion (CWI) and contrast water therapy (CWT). Despite numerous publications a lack still exists with regard to these specific recovery methods on physical and haematological parameters. Against this background, the main objectives of this study were firstly, to determine the effects of CWI compared to those of passive recovery (PAR) over a 48-hour period on physical and haematological parameters after an intense anaerobic exercise session in a cohort of male university-level rugby players. Secondly, to determine the effects of CWT compared to those of PAR over a 48-hour period on physical and haematological parameters after an intense anaerobic exercise session in a cohort of male university-level rugby players. Twenty-three rugby players of the North-West University participated in the study. The players were randomly assigned to either a control (n = 11; age: 20.1±0.3 y) or experimental (n = 12; age: 19.9±0.3 y) group. Participants reported to the laboratory where base line measurements were taken on certain physical (vertical jump test (VJT) height, VJT peak speed, VJT peak power and grip strength) and haematological (base excess (BEx), blood lactate (BLa-), calcium (Ca+), bicarbonate (HCO3), haemoglobin, haematocrit, pH level, partial oxygen level (PO2), partial carbon dioxide (PCO2), plasma glucose, potassium (K+), saturated oxygen (SO2), sodium (Na+) and total carbon dioxide (TCO2)) components. Thereafter participants were accompanied to the field to complete an intense anaerobic exercise session, followed by a recovery period of either CWI vs. PAR (week 1) or CWT vs. PAR (week 2). The recovery session comprised of either sitting passively in a still area (PAR), or immersion of CWI (8–10°C), or alternating immersions of five cycles between cold (1 min; 8–10°C) and warm water (3min; 40-42°C), totalling 20 minutes. Exactly three minutes, 24 and 48 hours after the recovery intervention all the measurements were re-taken to assess acute and longer-term effects of recovery. Descriptive statistics were followed by a linear mixed model analysis with an autoregressive 1 heterogeneous (AR1-Heterogeneous) structure, and between-group differences were examined using a one-way analysis of variance (ANOVA). Significance was set at p ≤0.05. Effect sizes were calculated to determine practical significance per recovery intervention as well as within groups. CWI indicated better recovery than PAR, with three out of the nine variables (BLa-, Na+ and haemoglobin) returning at 0 h post-recovery, and five (PO2, plasma glucose, VJT height, VJT peak power, VJT peak speed) only at 24 h post-CWI. In contrast, the PAR-group did not demonstrate recovery in any of the variables at 0 h post-PAR. However, an improvement was seen in VJT height across all time points. Four (BLa-, haemoglobin, VJT peak power and VJT peak speed) out of a possible nine variables recovered at 24 h with an additional two (PO2 and grip strength) variables showing recuperation at 48 h. A significant decrease (p ≤0.05) was seen in VJT height, PO2 and Na+ from post-anaerobic to immediately following either CWI or PAR (except for VJT height). Significant increases (p ≤0.05) were observed in VJT height, plasma glucose, and Na+ from 0 h post-recovery to 48 h post-recovery for both CWI and PAR. PO2 also significantly increased (p ≤0.05) from 0 h to 24 and 48 h post-CWI and for the PAR-group at 48 h. CWI tended to have a faster recovery rate than PAR over a 24-h period. The CWT vs. PAR showed the same trend, at 0-hours, six variables (BLa-, haemoglobin, VJT-height, VJT peak-power, VJT peak-speed and grip strength) was restored to base line, whereas plasma glucose recovered at 24-hours post-CWT. In addition, players’ jump and grip strength performance improved from base line. The PAR-group demonstrated recovery at 0 hours in four variables (BLa-, VJT height, VJT peak-speed and grip strength), and two variables (Na+ and haemoglobin) at 24-hours and plasma glucose at 48 hours. A significant decrease (p ≤0.05) was seen in haemoglobin and BLa- from post-anaerobic to either 24 or 48 hours for both groups. A significant increase in plasma glucose and PO2 from 0 to 24 hours was observed in both groups. No significant intergroup change in physical components was noticed. However, intergroup results indicated CWT to be superior to PAR with statistical significance observed in BLa- and grip strength (p ≤0.05) at various time points. The conclusion drawn from the above-mentioned results is that a recovery session comprising either 20-minutes of CWI or CWT may lead to significantly better physical components and restoration of haematological components in university-level rugby players compared to that of passive recovery. However, a detrimental effect was noticed in some components over the recovery period.
MA (Sport Science), North-West University, Potchefstroom Campus, 2015

Title: The influence of water temperature on the rate of recovery during repeated isometric exercise. Objectives: The aim of this thesis is to assess the effect of water temperature on immersion of forearm to water for the sake of speeding up the recovery process during repeated isometric performance. Methods: Five male subjects from the students of FTVS (average age 22 ± 3 years) underwent three meaurements with repeated exercise to exhaustion with various kinds of rest periods. The exercise was represented by three series of intermittent isometric contraction of the finger flexors until exhaustion with 20 minutes rest period. The rest period was represented by the immersion of forearm into cold water (8řC; 15řC;) as well as by a passive rest. Sturation O2 of saturated hemoglobin (SmO2) was monitored by the spectrometer throughout the entire measurements at flexor digitorum profundus. Results: The reliability of measurements was rel=0,79 with standard deviation SD= 27,3s and standard measurement error SEM= 12,5s. The least effective method of recovery was passive recovery. Decrease in the time between the first, second and third contraction respectively was 35s, 34s respectively. Immersion in 15 ř C water under recovery phase led to improvement in the second contraction by 43s and by 27s in the...

Title: Effect of water temperature during cold water immersion on repeated isometric performance Objectives: The aim of the study was to evaluate the effect of water temperature on recovery using repeated isometric performance of finger flexors to exhaustion Methods: The study was attended by a group of climbers consisting of 16 men (aged 30.8 ± 7.2 years) and 18 women (aged 26.7 ± 4.5 years). Participants came 3 times in the laboratory, where repeated intermittent isometric performance until exhaustion with different recovery strategy (passive recovery, immersion of forearm to 8ř C water - CWI 8, immersion of forearm to 15ř C water - CWI 15) were completed Results: The results were evaluated according time of contraction and force- time-integral (FTI). After passive recovery, the second time of contraction dropped by ↓ 9% and the third contraction by 20% compared to the first one. In response to cold water (CWI), after CWI 8 second time of contraction increased by ↑ 32% and CWI 15 by ↑ 36% compared to the first one. The third time of contraction was worse for CWI 8 by ↓ 4%, and CWI 15 was better by ↑ 26% compared to the first contraction. Conclusion: Cold water immersion is an effective recovery method between intermittent isometric performance compared to passive recovery strategy. CWI 15 is more...

The molecular signals underlying improvements in the skeletal muscle capacity for K+ regulation and Na+,K+-ATPase expression in humans are poorly understood. Further, fibre-type-specific regulation of Na+,K+-ATPase isoforms by exercise training appears inadequately explored. This thesis investigated in humans possible mechanisms regulating the muscle’s capacity for K+ regulation and Na+,K+-ATPase-isoform expression in different fibre types with exercise training and presents a novel method for fibre type identification of single muscle fibres. Molecular signals (oxidative stress, hypoxia, lactate, AMPK- and Ca2+-signalling) were modulated by exercising with and without blood flow restriction (BFR), and in systemic hypoxia, and changes in expression of Na+,K+-ATPase genes were examined by RT-PCR. In another experiment, an intra-subject design was used, where one leg trained with and the other leg without BFR, along with measurement of thigh K+ release. Effects of cold-water immersion on training-induced adaptations in Na+,K+-ATPase isoforms were also examined. The reliability and validity of dot blotting for fibre-type determination of single muscle fibres were evaluated by use of western blotting. Key findings were that increased oxidative stress, AMPK signalling, and disturbance of ionic and redox homeostasis are positively associated with training-induced increases in the capacity for K+ regulation and Na+,K+-ATPase-isoform expression. In contrast, the level of hypoxia and lactate concentration, and modulation of CaMKII signalling, was not related to the regulation of Na+,K+-ATPase-isoform expression. Fibre type-dependent adaptations of Na+,K+-ATPase expression were associated with improvements in K+ regulation and exercise tolerance. In addition, dot blotting was valid and reliable for fibre type determination of single muscle fibres. In conclusion, this thesis has identified key mechanisms underlying, and a novel strategy (BFR training) to augment, training-induced improvements in K+ regulation by human skeletal muscle and presents a valid and reliable method for easy and rapid fibre type determination of individual muscle fibres.

Title: Effect of cold water immersion on intermittent isometric forearm flexor contractions to failure in rock climbers Objectives: The aim of this study was to determine the effect of cold water immersion on intermittent isometric forearm flexor contraction to failure in rock climbers. Methods: Thirty-two climbers (15 male and 17 female) completed three intermittent trials to failure, on a climbing-specific handgrip dynamometer, on three separate visits to the laboratory. For each visit a different recovery strategy was employed: passive recovery (PAS), cold water immersion at 8 řC (CWI 8) or 15 řC (CWI 15). The force time integral (FTI - time of contraction multiplied by the force of contraction) was determined to assess intermittent performance. The tissue saturation index (TSI) and total haemoglobin (tHb) during isometric contractions from near-infrared spectroscopy (NIRS) were determined to assess hemodynamic changes. Differences between repeated trials and three recovery protocols, derived parameters NIRS, were assessed using repeated measures ANOVA with Bonferroni corrections. Results: There was no significant difference between conditions after trial one. In response to the PAS recovery condition there was a 10% and 22% decrease in FTI in the second and third trials, respectively. The PAS...

Title: The effect of active recovery and hydroterapy on the subsequent short-term and medium-term muscular performance Objective: The aim of the study was to compare the effect of two recoveries (ice pack, passive recovery) on the subsequent short-term and three recoveries (active recovery, cold water immersion, passive recovery) on the medium-term knee strength in the extension and flexion. Methods: Fourteen athletes in an average age of 26,6±4,4 years performed, in a random cross-over design, 2 sessions with 5 repeated short-term isokinetic tests and 3 sessions with 3 repeated medium-term isokinetic tests. The effect of ice packs and passive rest and the effect of active recovery, passive rest and cold water immersion were assessed by the 5x2 (time x recovery) and 3x3 (time x recovery) repeated-measure ANOVA, respectively. Results: The ice packs did not have any effect on peak torque, total work and average power during short-term performances. The average heart rate was significantly lower during measurements with the ice packs than during the passive recovery (125±15 vs. 135±20 tepů. min-1 ). We stated significantly lower changes in knee extension for the peak torque after the active recovery (↑ 0,9 N.m) than after the cold water immersion (↓ 14,6 N.m) or the passive recovery (↓ 13,9 N.m). The...