Dissertations / Theses on the topic 'High intensity interval training'

High-intensity interval training (HIIT) consists of short intervals of exercise at high intensity intermitted by intervals of lower intensity and is associated with improvement of body composition and metabolic health in adults. Studies in overweight adolescents are scarce. We conducted a randomized controlled trial in overweight adolescents to compare acceptance and attendance of HIIT with or without weekly motivational encouragement through text messages and access to a study website. HIIT was offered for six months (including summer vacation) twice a week (60 min/session). Participation rates were continuously assessed and acceptance was measured. Clinical parameters were assessed at baseline and after six months. Twenty-eight adolescents participated in this study (age 15.5 +/- 1.4; 54% female). The standard deviation score for body mass index over all participants was 2.33 at baseline and decreased by 0.026 (95% CI - 0.048 to 0.10) units, p = 0.49. Waist to height ratio was 0.596 at baseline and decreased by 0.013 (95% CI 0.0025 to 0.024), p = 0.023. Participation within the first two months ranged from 65% to 75%, but fell to 15% within the last three months. Attendance in the intervention group was 14% (95% CI - 8 to 37), p = 0.18, higher than the control group. Overall program content was rated as \"good\" by participants, although high drop-out rates were observed. Summer months constitute a serious problem regarding attendance. The use of media support has to be assessed further in appropriately powered trials.

The purpose of this study was to compare energy expenditure between high intensity interval training (HIIT) and agonist-antagonist (SUPER) resistance training (RT) exercise protocols. Twelve males (23.91 ? 3.58 years) with at least six months of RT experience were recruited for the study. Each participant completed both exercise protocols while VO2, lactate, respiratory exchange ratio (RER), heart rate (HR), and rating of perceived exertion (RPE) were measured. Significant differences were seen in RPE, RER, aerobic, anaerobic, and total overall energy expenditure when comparing protocols. There were no significant differences in VO2 or HR. Rest interval length and volume load can play a part in energy expenditure, but whether other variables are affected has yet to be shown when comparing HIIT to SUPER. In this study HIIT elicited a higher total energy expenditure than SUPER despite an overall shorter duration and a lower one-repetition maximum percentage for each exercise.

Low levels of fitness are associated with increased body mass index (BMI), both of which are related to quality of life (QoL) and the occurrence and severity of asthma. Therefore, the purpose of this thesis was to co-develop and implement a six-month high-intensity interval training (HIIT) intervention targeting aerobic fitness, BMI and QoL improvements in adolescents with asthma. Six-hundred and sixteen adolescents (13.0±1.1years; 155 asthma; 85% mild asthma as defined by medication-step) participated in the study, with 223 enrolled in the school based HIIT intervention (50 asthma), consisting of 10-30second bouts at >90%age-predicted maximum heart-rate with equal rest, 3x30minutes/week. Formative group interviews to elicit the views of adolescents with and without asthma on asthma and exercise were used to inform the design of the intervention. Anthropometrics, aerobic fitness, lung function and QoL were measured at baseline, mid-point and post-intervention to evaluate the intervention’s impact; follow-up measures were also taken to evaluate sustainability. Focus groups revealed participants with asthma had a fear of asthma attack through exercise, although fear did not act as a barrier, and that the intervention should be varied to circumvent activity-specific anxieties. Participants with asthma were found to have higher BMI and lower physical activity in comparison to their peers, but no difference in cardiorespiratory fitness. The intervention elicited significant improvements in peak cardiorespiratory fitness, irrespective of asthma, while maintaining BMI which increased in the controls; no changes were observed in the sub-maximal exercise parameters, QoL or lung function. The present findings suggest that HIIT may be effective at increasing peak cardiorespiratory fitness and preventing increases in BMI in adolescents, irrespective of asthma status. Overall, the series of studies show that asthma does not deleteriously influence maximal and sub-maximal aerobic fitness, or trainability in adolescents, and that HIIT is a safe exercise modality for adolescents with asthma.

Endurance athletes typically spend the large majority of training (> 70%) at low intensities (i.e. below lactate threshold) coupled with short and intermittent bouts of high-intensity exercise or interval training (HIIT). Despite HIIT being a relatively small part of training in terms of duration, it has a substantial effect on the adaptations to endurance training. While it is well-established endurance exercise performance is affected in both hot and cold environmental conditions, the effect ambient temperature (TA; frequently referred to as environmental temperature) has on HIIT as performed by an endurance athlete population is not well understood. Therefore, the overall purpose of this thesis was to investigate the effects TA has on HIIT in an endurance trained population. Specifically, this thesis aimed to increase the understanding of how TA acutely affects performance and physiological responses during high-intensity intervals (Study 1); how repeated exposure to TA manipulates physiological responses during high-intensity intervals (Study 2), and how TA affects performance outcomes of a HIIT intervention (Study 3). In Study 1, eleven well-trained cyclists completed 4 interval sessions at 5°C, 13°C, 22°C, and 35°C (55 ± 13% RH) in a randomised order. Each session involved 5 x 4-minute intervals interspersed with 5 minutes of recovery. During the intervals, power output, core temperature (TC), oxygen consumption (VO2), and heart rate (HR) were recorded. It was hypothesized that the 13°C condition would have the highest mean power output compared to the other TA conditions. However, mean session power output for 13°C (366 ± 32 W) was not significantly different than 5°C (363 ± 32 W), 22°C (364 ± 36 W), or 35°C (352 ± 31 W). Power output was lower in the 5th interval of the 35°C condition, compared with all other TA. TC was higher in 22°C compared with both 5°C and 13°C (P= .001). VO2 was not different across TA. HR was higher in the 4th and 5th intervals of 35°C compared with 5°C and 13°C. It was concluded well-trained cyclists performing maximal high-intensity aerobic intervals can achieve near optimal power output over a broader range of TA than previous literature may indicate. Study 1 indicated TA had acute effects on performance and physiological responses during high-intensity aerobic intervals, especially in terms of cardiovascular stress. However, whether acute cardiorespiratory and thermoregulatory responses during high-intensity intervals change as a result of repeated TA exposures (i.e. during HIIT) was unknown. In Study 2, 20 trained cyclists and triathletes completed a 4-week (8 session) HIIT intervention in either cool (13°C) or hot (35°C) conditions. The HIIT intervention utilized the interval protocol from Study 1 and recorded cardiopulmonary and thermoregulatory measures during the first (INT8) and last (INT8) sessions. It was observed that time spent at or near maximal oxygen consumption (VO2max) during HIIT was greater in 13°C (877 ± 297 seconds) than 35°C (421 ± 395 seconds), but did not change for either TA condition between INT1 and INT8. HR was not significantly different between 13°C (164 ± 9 bpm) and 35°C HIIT (164 ± 12 bpm). TC significantly decreased in 35°C HIIT between INT1 and INT8. These results potentially indicate the relationship between time spent at or near VO2max and cardiovascular strain during HIIT is influenced by TA. Additionally, HIIT performed intermittently (~2x per week) at 35°C resulted in demonstrated evidence for heat acclimation in endurance athletes. Study 1 and Study 2 provided findings for performance, cardiorespiratory, and thermoregulatory responses during acute high-intensity interval sessions and after repeated exposure to TA. In particular, differences in time spent at or near VO2max between 13°C and 35°C HIIT, and changes in thermoregulatory responses over the course of a HIIT intervention both have the potential to affect endurance performance outcomes and coinciding physiological responses. In order to investigate this, Study 3 evaluated submaximal warm-ups and 20 km time-trials in temperate conditions (22°C) before (TT1) and after (TT2) the HIIT interventions from Study 2. Gross mechanical efficiency (GME) was measured during the warm-up (at 50% peak power output), whilst power output and HR were measured during the 20 km TT. Rate of perceived exertion (RPE) and body temperature (TB) were measured through the warm-up and time-trial. It was demonstrated that time-trial power output was increased after HIIT interventions in both the 13°C (3%; HIIT13) and 35°C (7%; HIIT35), yet no differences between groups for power output, HR, or RPE were noted. Within subject increases for HR and RPE during the 20 km time-trial were noted in HIIT13, but not in HIIT35. GME approached a significant decrease (P= .051) in HIIT13. A significant interaction in TB was observed between groups and TT1 and TT2 during both the 20 km time-trial and submaximal warm-up. These findings indicate that HIIT performed in hot and cool conditions result in similar temperate time-trial performance outcomes. However, changes in cardiorespiratory, thermoregulatory, and subjective responses during aerobic exercise after a HIIT intervention appear to be dependent on the TA HIIT is performed in. The results of this thesis demonstrate TA acutely affects performance, and cardiorespiratory and thermoregulatory responses during high-intensity intervals; repeated exposures to TA during HIIT can stimulate changes in thermoregulatory responses; and TA exposure during HIIT has limited effect on temperate endurance performance, yet affects coinciding cardiorespiratory, thermoregulatory, and subjective responses. These findings will assist coaches and athletes to make better informed decisions relating to HIIT prescription and acclimating endurance athletes to TA.

Thesis (M.A.)--Boston University
In the fast-paced lifestyle of modern-day society, people often feel overwhelmed by their list of things to do. It is no surprise then that a lot of people claim that they have "no time" to exercise. Two short-duration programs-circuit training and high intensity interval training-seem to be the answer to this issue, and this report investigates each program to see if one is more beneficial than the other in regards to population health. Factors taken into consideration for this comparison include cardiovascular responses, metabolic responses, and psychological factors. Research was gathered through PubMed, Web of Knowledge, and interviews with certified physical trainers to reach an evidence-based conclusion on whether circuit training or high intensity interval training was more beneficial. The Published Data section presents relevant data from the scientific literature in The Effects of Circuits & High Intensity Interval Training on the Cardiovascular System, The Effects of Circuits & High Intensity Interval Training on Body Metabolism, and Psychological Changes Associated with Circuits & High Intensity Interval Training, and is presented by first detailing methodological data, followed by the study's findings. The implications of the results, along with any possible extraneous factors, will be evaluated in the Discussion section.

This thesis comprised two studies: a systematic review and a pilot randomised controlled trial. The review aimed to evaluate what is known regarding aquatic high intensity interval exercise training and its effect on aerobic capacity and body composition in populations that are not athletic. This knowledge was then used to develop, implement and evaluate the feasibility of this type of training for young people with cerebral palsy.

The purpose of this study was to investigate the effects of a high intensity interval training program (HIIT) using the upper extremities on peak oxygen uptake (VO_2peak), peak heart rate (HR_peak), total time-to-fatigue (TTF), peak power output (PPO), rating of perceived exertion (RPE), and blood lactate concentrations (bLa). Results showed significant (p ≤ 0.05) improvements by the HIIT group in VO_2peak, HR_peak, PPO, and TTF when compared to a continuous training (CT) group.

Results of this study suggest that upper extremity HIIT appears to produce greater improvements in several physiological outcome measures when compared to CT and may be an effective way to improve cardiopulmonary fitness. Furthermore, a HIIT program using the upper extremities as little as 2 days per week appears to be a viable way to improve factors that contribute to cardiopulmonary fitness, muscular fitness, and performance, while being an efficient use of time.

Contemporary aerobic exercise guidelines comprised of continuous durations and higher intensities have been shown to be effective in the prevention and treatment of risk factors associated with obesity and cardiovascular disease (CVD). However, high-intensity interval training (HIIT) has recently been examined as an advantageous protocol for producing more favorable physiological and psychological benefits in comparison to traditional continuous exercise guidelines. The dual-mode model, which examines the dose response relationship between exercise intensity and affective valence, would suggest that exercise performed well above the ventilatory threshold (VT) in the severe domain should result in negative affective valence.

Numerous investigations have confirmed the reliability of the dual-mode models ability to predict compromised affective valence in the presence of heavy to severe exercise intensities, but only a small amount of research has examined the efficacy of the dual-mode model during HIIT. However, no research to date has combined HIIT with the dual-mode model's efficacy to predict affective valence in target populations challenged by exercise adherence, such as overweight and sedentary individuals. Therefore, the purpose of this study was to examine the dual-mode model's reliability to predict affective valence for overweight and sedentary individuals performing HIIT.

A total of 14 participants (7 male, 7 female) with a mean age of 23 ± 4 (range = 18-33) and mean BMI of 29 ± 3 (range = 25-33) completed the study. Each participant completed a ramp maximal exercise test to determine VT and peak power data, which allowed for specific exercise intensities of delta (DT) to be prescribed for experimental trials. Participants were low to moderate risk. The four experimental conditions were all matched for total work: 1) continuous at 10% DT (Continuous-Heavy - CH), 2) 24 × 30-second intervals at 60% DT (Interval-Severe 30 Second - IS30), 3) 12 × 60-second intervals at 60% DT (Interval-Severe 60 Second - IS60), 4) 6 × 120-second intervals at 60% DT (Interval-Severe 120 Second – IS120). The continuous exercise condition was 20 minutes in duration, whereas all interval exercise conditions were 24 minutes in duration.

Results indicated that in-task perceptual responses defined, as affective valence and perceived enjoyment were overall more favorable during IS30 and IS60 in comparison to CH and IS120. IS30 was the only experimental condition in which affective valence did not decline significantly (p > 0.05). Ratings of perceived enjoyment were greater at all measured time points during IS60 (p < 0.05) in comparison to CH. The findings of this study suggest that HIIT comprised of 30 and or 60 seconds help to facilitate more favorable perceptual responses of affective valence and perceived enjoyment than continuous exercise and intervals of longer than 60 seconds duration.

Critical Power (CP) is the greatest power that a person can sustain for prolonged periods of time while maintaining steady state conditions. Work-prime (W’) is the amount of work that can be tolerated when exercising in non-steady-state conditions above CP. A person’s CP and W’ strongly influence the metabolic response and tolerance to exercise. PURPOSE: Compare the effect of equal amounts of moderate intensity continuous training (MICT) and high intensity interval training (HIIT) on CP and W’. Critical Power (CP) is the greatest power that a person can sustain for prolonged periods of time while maintaining steady state conditions. Work-prime (W’) is the amount of work that can be tolerated when exercising in non-steady-state conditions above CP. A person’s CP and W’ strongly influence the metabolic response and tolerance to exercise. PURPOSE: Compare the effect of equal amounts of moderate intensity continuous training (MICT) and high intensity interval training (HIIT) on CP and W’. METHODS: Twenty-two (10 female) untrained, young (26.4 ± 0.9 years) adults completed 8 weeks of cycling training (40 min, 3  per week) administered as either MICT cycling (44% max work rate achieved during a maximal graded exercise test; GXTmax) or HITT cycling (4 bouts at 80% GXTmax for 4 min with recovery intervals between). Cycling V̇O2max, CP, W’ and Anaerobic Capacity (i.e., Wingate) were determined before and after training. Specifically, CP was assessed with the work-over-time method derived from 4–5 constant-power tests to exhaustion. RESULTS: MICT (n = 11) and HIIT (n = 11) groups completed the same amount of work over the course of the training (P = 0.76). CP significantly increased in both groups, but to a greater extent in the HIIT group (MICT: 15.7 ± 3.1% vs. HIIT: 27.5 ± 4.3%; P = 0.04). The work that could be performed above CP (i.e., W’) was not significantly impacted by training (p = 0.76). V̇O2max significantly increased in both groups (P < 0.01), and the magnitude tended to be greater in the HIIT group (MICT: 8.3 ± 2% vs. HIIT: 14 ± 2.6%; P = 0.09). Interestingly, the training-induced change in CP was not significantly related to the training-induced change in V̇O2max. The training-induced increase in CP exhibited a positive curvilinear relationship with the training intensity, expressed as a percentage of the initial CP, with those performing the same workout at a greater percentage of CP exhibiting greater training-induced increases in CP (R2 = 0.49, P < 0.01). CONCLUSION: HIIT elicits approximately twice the increase in CP than an equal amount of MICT in untrained young adults. Moreover, the magnitude of increase in CP is strongly related to the intensity of the exercise, relative to CP, even when exercising at the same percentage of GXTmax. Thus, exercise may be more effectively prescribed relative to CP, rather than V̇O2max or GXTmax.

INTRODUCTION Research in sport and exercise science suggested that both placebo and nocebo can influence sport performance (1), with effect ranging from small to moderate (2). Most of studies proposed as treatment nutritional ergogenic aids or peripheral stimulation. However, a more ecological approach lowered into a conventional training session, could exploit some parts of the training itself to administer placebo/nocebo effect. The aim of the present study was to test the effect on the running performance of a placebo/nocebo treatment consisting in conditioning manipulation plus verbal suggestion. METHODS Thirty-nine active young students (mean age 22±0.9) were randomly assigned to CONTROL group, PLACEBO group and NOCEBO group. The experiment consisted in 3 sessions. During TEST Session participants performed the Cooper test to evaluate the cardiorespiratory fitness. During SESSION 1, they performed a high intensity interval training (HIIT) protocol till exhaustion (30s all-out, with 2 min of passive recovery) preceded by a conventional warm-up (20min, running and dynamic stretching). During SESSION 2, warm up consisted in the FIFA 11+ (20min, running and balance exercises) (3), and was used as conditioning treatment. Participants’ expectancy about warm-up efficacy in not-changing/improving/worsening the following HITT performance was manipulated through verbal suggestion in CONTROL/PLACEBO/NOCEBO groups. At last, during the HIIT rest-period a surreptitious manipulation, consisting in none/positive/negative verbal feedback about the current performance, was administered to CONTROL/PLACEBO/NOCEBO group. The time to exhaustion (TTE) and total running distance (TRD) were considered as performance outcome. The rate of perceived exertion (RPE), maximal heart rate (HR) and blood lactate ([LA+]) were used to determine whether participants reached the exhaustion. ANOVA was applied to evaluate normally-distributed parameters, whilst non parametric analysis were applied to not-normally distributed data. RESULTS TTE and TRD values of the PLACEBO group significantly increased in SESSION 2 with respect to SESSION 1 whilst they significantly decreased in NOCEBO group (p<0.05 and p<0.01, respectively). Further, TTE (p<0.05) and TRD (p<0.01) in SESSION 2 of the PLACEBO group was significantly higher than those of NOCEBO group. No differences appeared in the CONTROL group. No differences among groups and session were found in RPE, HR and [LA+]. CONCLUSION The innovative placebo/nocebo treatment proposed in this study succeeded to improve/worsen the running performance of active young adult. These results provide insight on the interaction between the athlete’s cognitive domain and the running performance and pave the way for the application of combined cognitive/motor strategies during training.
Purpose: The aim of this study was to compare the acute cardiorespiratory and metabolic effects induced by a High-Intensity Continuous Training (HI-CT) and three High-Intensity Interval Training regimes (HIITs) in young active students. The assessment of internal training load through the rate of perceived exertion (RPE) at iso-time was also a focus. Methods: Fifteen active university students (age: 21.0±1.1 ys, height: 1.74±0.9 m, weight: 64.8±12.9 kg, VO2max 48.1±7.5 mL∙kg-1∙min-1) performed an incremental treadmill test to assess VO2max and maximal aerobic speed (MAS). Then, each participant performed, on testing sessions, separated by a minimum of 72 h and in a randomized order, one HI-CT session at 95% MAS for 8 minutes and three different HIIT sessions (10s-20s, 30s-30s, 50s-30s) with a work phase at 95% MAS and an active recovery at 40% MAS for 16 minutes. Oxygen consumption (VO2), heart rate (HR), time spent near or above 90%VO2max (T@90%VO2max) and blood lactate concentration ([La]+) were measured. The rating of perceived exertion (RPE), by the Borg’s CR 10 scale, was used to assess the subjective level of fatigue experienced at the end of each testing session. Results: The statistical analysis revealed that VO2peak, HRpeak, T@90%VO2max, and RPE values in 10-20 HIIT were significantly lower compared to 30-30 and 50-30 HIIT regimes (p always <0.001). In HI-CT session VO2peak, HRpeak, T@90%VO2max were significantly higher than in 10-20 and 30-30 sessions (p<0.0001 and p<0.05). Blood lactate values were significantly higher in HI-CT and in 50-30 and 30-30 HIITs, compared to 10-20 protocol. Finally, internal workload in HI-CT and 50-30 HIIT was significantly higher than those in 30-30 (p<0.01) and 10-20 (p<0.0001) HIIT sessions. Conclusions: Our results show that in active young subjects a HI-CT and a long work interval HIIT regime (50-30) represent an optimal training stimulus to elicit higher physiological and metabolic responses compared to short work interval HIIT regimes (30-30 and 10-20), being the most effective for stressing both the aerobic and anaerobic energy systems. Coaches can choose and balance the level of aerobic/anaerobic energy requirements and neuromuscular engagement associated with the three HIIT regimes and a HI-CT protocol based on the expected physiological and metabolic adaptations as well as neuromuscular characteristic and ability level of the athlete/subject individual profile.
Purpose: High-Intensity Interval Training (HIIT), in a variety of forms, is today widely used to improve cardiorespiratory and metabolic function of moderately- or well-trained subjects. The aim of this study was to examine physiological and metabolic responses to three different short-bout HIIT regimes in young active subjects. Methods: Twenty healthy active university students (age: 22.80 ± 2.76 years, height: 178.85 ± 8.64 cm, body mass: 72.51 ± 11.47 kg) were enrolled in this study. They performed one incremental treadmill test to determine the VO2max and maximal aerobic speed (MAS). Then, each participant performed, on separate days, in a randomized order: 1) 15 repetitions of bouts of 10 s at 40% MAS and 10 s at 120%MAS (10-10); 2) 15 repetitions of bouts of 15 s at 40% MAS and 15 s at 120%MAS (15-15); 3) 15 repetitions of bouts of 20 s at 40% MAS and 20 s at 120%MAS (20-20). Peak oxygen consumption (VO2peak), volume of carbon dioxide (VCO2) and heart rate (HR) were continuously monitored during each session. Respiratory-exchange ratio (RER) and blood lactate concentration ([La]) were measured after the end of exercise. The psychophysiological stress was evaluated by the whole-body rating of perceived exertion (RPE), measured by the Borg’s CR 10 scale. Results: The results showed significantly lower VO2peak, VCO2 and blood lactate values in 10-10 protocol, than either in 15-15 or in 20-20 protocol (always p.001). Maximal HR values were the lowest in 10-10 (p.0001), followed by those in 15-15, which, in turn, were lower than those in 20-20 (p.01). RER values recorded in 10-10 protocol were significantly lower than those obtained in 20-20 session (p.05). Similarly, RPE values measured at the end of 10-10 session were the lowest (always p.01), followed by those of 15-15 protocol, that were, in turn, lower than those obtained after the 20-20 regime (p.05). Conclusions: Under our experimental conditions, 15-15 and 20-20 HIIT regimes induced significantly higher VO2peak, RER and ([La]) values, compared to those recorded during 10-10 protocol, whereas maximal HR and RPE were lower during 15-15 and 10-10 compared to 20-20. These results suggest that 15-15 is the most effective short HIIT modality for young active subjects to determine acute cardiorespiratory and metabolic responses, combined with a sustainable perception of effort, also in view of a RPE-based prescription of exercise intensity.
This study investigated the effects of two High Intensity Interval Trainings (HIITs) on physiological and metabolic responses and performance parameters, in elite adolescent rowers. Ten elite adolescent male rowers (15.7±0.2 years) were enrolled. A randomized-crossover trial consisting of a 1500 m all-out rowing exercise test and two HIIT sessions (Short: S-HIIT; Long: L-HIIT) matched per training volume, was designed. The L-HIIT consisted of 4x4 min at P@90% of Peak Power Output (PPO) interspersed with 3 min of active recovery (P@30%PPO) while the S-HIIT consisted of 25 repetitions of 30 s at P@100%PPO interspersed with 30 s of active recovery (P@20%PPO). Physiological and metabolic responses and rowing performance parameters were evaluated. The internal workload through the rating of perceived exertion (RPE), was also assessed. ANOVAs were applied and significance level was set at p<0.05. Oxygen Uptake (VO 2 ) (p<0.05), time spent per session in exercise bouts at an intensity close to 90% VO 2 max (T@90%VO 2 max) (p<0.01), Total VO 2 (TotVO 2 ) and blood lactate ([La] + ) (p<0.0001) were significantly higher in L-HIIT than in S-HIIT. Total distance (TD) was significantly higher and PPO was significantly lower in L-HIIT compared to S-HIIT (p<0.0001), respectively. Finally, RPE was significantly higher in L-HIIT respect to S-HIIT (p<0.0001). Our results show that, in elite adolescent rowers, L-HIIT stimulates both aerobic and anaerobic systems to a greater extent and with better performance than S-HIIT. We recommend coaches to incorporate HIIT into the traditional training program, given its effectiveness in improving cardiorespiratory parameters along with a reduced training volume.
Aim. Small-Sided Games (SSGs) represent a widely used training modality to develop concurrently physical performance and technical-tactical skills in soccer players1 as well as in other team sports2. This study aimed to compare external and internal training loads in élite junior soccer players between two different SSGs (only ball possession, SSG-POS; ball possession play, and shuttle run after the pass, SSG-SHU) and those of official matches (OM). Methods. Ten élite young male soccer players (age 18.6±1.9 years; weight 73.1±5 kg; height 175± 1.5 cm) were recruited from Under 19 Italian professional team and monitored during 10 official championship matches of the corresponding age category. Players performed two different 5vs5 SSGs (SSG-POS and SSG-SHU) of the same duration (4x4 min–1min rest), 2 times each, in a randomized order, one per week for 4 weeks. SSGs sessions and OM data of locomotor activity were recorded using 10-Hz Global Positioning System. Total distance (TD), Distance at high speed (DHS; 14.4–19.8 km·h-1) (m), distance at very high speed (DVHS; 19.8–25.2 km·h-1) (m); average metabolic power (AMP;W·kg-1); high and very high intensity accelerations (HA; ≥2/3 m·s–2), high and very high intensity decelerations (HD; ≤–2/-3 m·s–2) and the relative distance (Drel; m·min-1) were monitored. Heart rate (HR) was continuously recorded, whereas blood lactate [La]+ was measured at the end of each SSGs session. The internal training load was assessed through the rate of perceived exertion (RPE). ANOVA was applied to statistically evaluate normally-distributed parameters, whilst non parametric statistical analysis were applied to not-normally distributed data. Results. The comparison of locomotor activity parameters between the two SSGs formats showed that TD was higher (p<0.001) in SSG-SHU than in SSG-POS, whilst no significant differences were found in AMP, DHS, DVHS, Drel, HA, HD. HRpeak and RPE values did not differ between SSGs, while [La]+ values in SSG-SHU were significantly higher than in SSG-POS (p<0.001). The comparison between SSGs and OM showed higher values of AMP (p<0.05), HA (p<0.01) and HD (0.001) in SSGs compared to OM. DHS and DHVS values were higher in OM than in both SSGs (p<0.001), while Drel and HRpeak values did not differ between SSGs conditions and OM. Finally, internal workload measured through RPE was found to be higher (p<0.05) after OM, than after either SSG-SHU or SSG-POS. Conclusions. This study shows that SSG-SHU induces higher total distance covered with a higher solicitation of anaerobic energy contribution compared to SSG-POS. Furthermore, our results show that in young élite soccer players both SSGs, when compared to OM, might be an effective training regime in terms of average mean power and speed-based conditioning, with greater enjoyment and lower subjective perception of effort.

Despite clear recommendations on the minimal amount of physical activity for achieving health benefits and reducing risk of chronic disease, the majority of people in the Western world remain sedentary. As a 'lack of time' has been identified as one of the main barriers to becoming and remaining physically active, in the past decade research has focused on high-intensity interval training (HIT) as a time-efficient alternative to aerobic exercise. Although initial studies convincingly demonstrated equal or better health benefits with various HIT protocols compared to much larger volumes of aerobic exercise, these HIT protocols tend to be very strenuous and as such are unlikely to be adhered to by sedentary populations. Furthermore, most HIT protocols are not as time-efficient as sometimes claimed, with the total time per exercise session generally exceeding 20-30 minutes. This thesis aimed to characterise the effects of a novel reduced-exertion HIT (ReHIT) protocol, requiring a maximum of 2 x 20 s all-out sprint efforts in a 10 min training session, upon insulin sensitivity, aerobic capacity, glycogen utilisation and associated acute metabolic responses. The ReHIT exercise bouts were well tolerated by participants, but were associated with a substantial disturbance of physiological homeostasis including muscle glycogen degradation, lactate accumulation, excursions in plasma volume, post-exercise oxygen consumption, respiratory exchange ratio and heart rate, as well as a skeletal muscle signalling response through AMPK, and increases in skeletal muscle GLUT4 and PGC1α mRNA expression (Chapter 4 and 5). The combined training studies (n=49) provide some support for improvements in key disease biomarkers following ReHIT, with improvements in insulin sensitivity observed in men, and increased aerobic capacity observed in men and women (Chapter 7). These observations highlight a potential regulatory role for glycogen in exercise-induced adaptation. However, the mean improvements in insulin sensitivity in men were not consistent between the two training studies (Chapter 2 and 6), and there was a high level of variability observed between individuals (Chapter 6 and 7). Therefore, the impact of ReHIT on insulin sensitivity needs to be further explored in the context of a randomised controlled trial, and the mechanisms underpinning the large variability in adaptive response need to be characterised.

Background: Adults living with Severe mental illness (SMI) are at a high risk of cardiovascular disease. With the growing popularity for High-Intensity Interval Training (HIIT), some evidence suggests that there is potential to greatly reduce cardiovascular and metabolic risk factors and improve functional exercise outcomes in comparison to moderate-intensity continuous training (MICT). However, little research on HIIT has been done in SMI. Therefore, the aim of the study was to assess the feasibility of HIIT in adults living with SMI. A secondary aim was also proposed, to compare the effect of HIIT to a lifestyle intervention in relation to Cardiometabolic Risk Factor (CMRF) and functional exercise capacity. Method: Adults living with SMI, attending a service provided by the Collaborative Centre for Cardiometabolic Health in Psychosis (ccCHiP) were recruited to participate in one of two 10-week programs, during their visit. The programs offered were a HIIT (Intervention; 20-min HIIT session, three times per week) or a lifestyle program (Control; 30-min lifestyle education and 30-min circuit exercise program, once per week). Feasibility was assessed based on enrolment and withdrawal rates in each group. Lipid profile and 6-Minute Walk Test (6-MWT) were variables assessed for CMRF and functional exercise capacity, respectively. Result: 15 participants were recruited (Intervention = 11; Control = 4). A total of 4 participants withdrew from the study (Intervention = 3; Control = 1). No significant difference was found between the intervention and control for lipid profile and 6-MWT. Conclusion: Preliminary evidence suggests that HIIT may be a feasible program, based on the level of enrolment seen among adults with SMI.

It has been established that Wingate-based high-intensity training (HIT) consisting of 4 to 6 x 30-s all-out sprints interspersed with 4-min recovery is an effective training paradigm. Despite the increased utilisation of Wingate-based HIT to bring about training adaptations, the majority of previous studies have been conducted over a relatively short timeframe (2 to 6 weeks). However, activity during recovery period, intervention duration or sprint length have been overlooked. In study 1, the dose response of recovery intensity on performance during typical Wingate-based HIT (4 x 30-s cycle all-out sprints separated by 4-min recovery) was examined and active recovery (cycling at 20 to 40% of V̇O2peak) has been shown to improve sprint performance with successive sprints by 6 to 12% compared to passive recovery (remained still), while increasing aerobic contribution to sprint performance by ~15%. In the following study, 5 to 7% greater endurance performance adaptations were achieved with active recovery (40%V̇O2peak) following 2 weeks of Wingate-based HIT. In the final study, shorter sprint protocol (4 to 6 x 15-s sprints interspersed with 2 min of recovery) has been shown to be as effective as typical 30-s Wingate-based HIT in improving cardiorespiratory function and endurance performance over 9 weeks with the improvements in V̇O2peak being completed within 3 weeks, whereas exercise capacity (time to exhaustion) being increased throughout 9 weeks. In conclusion, the studies demonstrate that active recovery at 40% V̇O2peak significantly enhances endurance adaptations to HIT. Further, the duration of the sprint does not seem to be a driving factor in the magnitude of change with 15 sec sprints providing similar adaptations to 30 sec sprints. Taken together, this suggests that the arrangement of recovery mode should be considered to ensure maximal adaptation to HIT, and the practicality of the training would be enhanced via the reduction in sprint duration without diminishing overall training adaptations.

Cardiac rehabilitation (CR) programs usually consist of moderate intensity exercise sessions for the purpose of enhancing the physiological and psychosocial status of cardiac patients. It has been postulated that interval training is superior to the traditional continuous training in CR. Most of studies of interval training in cardiac patients have relatively small sample sizes, diverse training methodologies, and included heart failure patients. Furthermore, there have been relatively few comparisons of interval versus continuous exercise in a real life, center-based CR setting. This PhD thesis reports a single–site, randomized controlled trial of aerobic interval training in CR that was undertaken to address some of these concerns. Following 4 weeks of adjustment in the center, 84 coronary artery disease patients were randomly assigned to either an interval exercise group (IE) or a continuous exercise group (CE). Functional capacity, clinical outcomes and quality of life (QoL) were assessed at baseline and after 12 weeks of training. Both groups exercised twice a week under supervision at the center. The CE group exercised continuously at a moderate intensity (50-60% VO2max), whereas the IE group performed 2 minutes of low intensity (40-60% VO2max) followed by 2 minutes of moderate-high intensity (60-85% VO2max) interchangeably. Both groups increased VO2 peak significantly after training; however, IE was no better than CE at eliciting an improvement. In contrast, IE did elicit a significantly greater improvement in maximal power measured during cardiopulmonary exercise testing (CPET), as well as significant reductions in several sub-maximal variables. Some cardiac related risk factors, such as waist circumference, HbA1c% and hs-CRP were reduced in the IE group alone; however some of these changes do not seem to be clinically important. Next, measurements were repeated at 9 months to determine whether or not any of the training induced changes persisted at 6 months follow-up. Peak VO2 remained significantly higher versus baseline within the IE group only. High sensitivity (hs)-CRP was increased in the former CE group, and HDL-C was improved in the former IE group from 3 to 9 months. Finally, a single-group analysis (i.e. regardless of training modality) was undertaken to identify the best predictors of improvement functional capacity in cardiac patients. It was found that the magnitude of change in peak VO2 is dependent upon 6 factors: baseline body fat percentage, baseline left ventricular ejection fraction (LVEF), baseline fitness level, maximal rate pressure product during CPET, baseline psychological state, and number of exercise sessions completed. These observations indicate that interval training in a real life CR setting does not necessarily elicit higher peak VO2, but that it may have some superiority over continuous training in relation to exercise tolerance and performing daily activities. Furthermore, favorable changes may be preserved for up to 6 months following interval training. Finally, several factors that influence the magnitude of improvement in functional capacity following exercise training in CR patients have been identified. Using these factors, CR professionals may be able to identify those cardiac patients for whom the chances of improving functional capacity is low. Furthermore, it may be possible to focus on some of these factors in order to improve the prognosis for patients undergoing CR.

Colorectal cancer (CRCa) is the 4th most common cancer in the United Kingdom with 41,265 new cases diagnosed in 2014 (Cancer Research UK, 2017). Advancing age is an established risk factor for the development of CRCa (Figure 1.1); between 2012 and 2014 44% of new cancers were diagnosed in patients aged 75 years and over (Cancer Research UK, 2017). Due to our ageing population, national screening programmes and improved diagnostic techniques, a greater number of older people are now being diagnosed with CRCa. However older people are not surviving the disease as well as their younger counterparts. The 5 year survival rate from diagnosis of bowel cancer between 2009 and 2013 was 67.5% for 60-69 year old men and 45.5% for 80-99 year old men. This illustrates an increased burden of this disease in an ageing population (Cancer Research UK, 2017). In general terms, due to improvements in health screening and perioperative care, mortality from CRCa in all populations is decreasing over time. Indeed, the England and Wales age standardised 5 year survival rates for men with CRCa have increased from 24% in the early 1970s to 59% in 2010-11 (Cancer Research UK, 2017). Overall CRCa incidence is increasing over time but this is mirrored by improved survival rates. Age is a significant factor in reduced survival from colorectal cancer and efforts to improve outcomes in elderly CRCa patients should be investigated.

Due to the broad spectrum of physical characteristics necessary for success in field sports, numerous training modalities have been used develop physical preparedness. Sports like rugby, basketball, lacrosse, and others require athletes to be not only strong and powerful but also aerobically fit and able to recover from high-intensity intermittent exercise. This provides coaches and sport scientists with a complex range of variables to consider when developing training programs. This can often lead to confusion and the misuse of training modalities, particularly in the development of aerobic and anaerobic conditioning. This review outlines the benefits and general adaptations to 3 commonly used and effective conditioning methods: high-intensity interval training, repeated-sprint training, and small-sided games. The goals and outcomes of these training methods are discussed, and practical implementations strategies for coaches and sport scientists are provided.

This study investigated the effects of ungraded running and graded walking as modalities of HIIT on enjoyment, perceived exertion, and affect. 29 healthy males and females (aged 23.3 ± 5.1) volunteered to participate in the study. Participants completed six visits to the laboratory: the first was a medical screening to ensure safety of the participants. For the second and third visits, participants completed two maximal treadmill exercise tests, one running and one walking. On the fourth visit, the speed needed for the run HIIT (running speed: 6.9 ± 1.2mph) and the grade needed for the walk HIIT (walking speed: 3.3 ± 0.3mph, walking grade: 17.2 ± 3.1%) experimental trials were confirmed. During the last two visits, participants completed both of the two (run HIIT and walk HIIT) randomized and counterbalanced experimental trials. Affective valence was measured at baseline and post-exercise. The single-item Feeling Scale (FS) and the Borg 6-20 RPE scale (both overall exertion and legs-only exertion) were used to measure in-task ratings of affect and exertion. The Physical Activity Enjoyment Scale (PACES) and FS were used to measure post-exercise ratings of enjoyment and affect. Results revealed a main effect for condition for post-exercise enjoyment (p < 0.001), with the run HIIT being more enjoyable. A main effect was also found for time for both overall exertion and legs-only exertion (p < 0.001 for both interactions), with the walk HIIT producing higher exertion ratings. There was a main effect for condition of legs-only exertion (p = 0.004), again walk HIIT produced higher exertion ratings. Lastly, there was a main effect when comparing 20% and 100% of total time in the run HIIT and the walk HIIT conditions, for both overall exertion and legs-only exertion (p < 0.001 for all interactions). This shows that exertion increased over time for both conditions. Exertion ratings, both overall and legs-only tended to be highest during the run HIIT condition when compared to the walk HIIT. The opposite was true for affective valence, the ratings were higher in the run HIIT condition than the walk HIIT. In conclusion, the perceptual responses in this study, which represent enjoyment, exertion and affective valence, were generally more favorable during the run HIIT condition. These results support previous findings to suggest that doing a running protocol is a well-tolerated and favorable modality for HIIT exercise.

I denne oppgaven ble det undersøkt effekter av høyintensiv aerob intervall trening (AIT) blant personer med høyt blodtrykk og blant friske eldre og yngre personer. AIT med høy intensitet (>90% av maksimal puls) er mer effektiv for å øke kondisjonen og redusere risikofaktorer for hjerte- karsykdom sammenlignet med trening ved moderat intensitet (- 70% av maksimal puls). Dette er tidligere vist blant friske personer og pasienter med hjertesvikt, angina pectoris og metabolsk syndrom. Høyt blodtrykk (hypertensjon) er en viktig risikofaktor for hjerneslag, hjerteinfarkt og hjertesvikt., ansvarlig for 7 millioner dødsfall pr. år på verdensbasis. Om lag 30 % av den voksne befolkningen har høyt blodtrykk. I den første studien undersøkte vi effekten av trening ved høyt blodtrykk. AIT ble sammenlignet med en gruppe som trente ved moderat intensitet (MIT) og en kontrollgruppe. Begge treningsgruppene trente på tredemølle, 3 ganger per uke i 12 uker. Kontrollgruppen fikk standardiserte treningsråd, men ingen veiledet trening. Resultatene viste at begge treningsformer reduserte 24 timers blodtrykk og forbedret den systoliske (hjertets evne til å pumpe blod) hjertefunksjonen, men at AIT var mer effektiv til å senke systolisk blodtrykk (overtrykket), øke kondisjonen, forbedre kolesterolet og forbedre den diastoliske (hjertets evne til å fylle seg mellom hjerteslagene) hjertefunksjonen. I den andre studien trente friske eldre (>70 år) AIT 3 ganger per uke i 12 uker, og kondisjonen ble forbedret med 15 % (lik relativ økning som vist hos yngre personer). Resultatene ble sammenlignet med yngre friske personer og eldre (> 70 år) toppatleter (Birkebeinerresultat). Den diastoliske hjertefunksjonen ble forbedret til samme nivå som de eldre toppatletene, men den var fortsatt svært redusert sammenlignet med yngre personer. Hjertet til de eldre ble kraftigere og større etter treningen, men var fortsatt mindre enn hos de eldre toppatletene. I den tredje studien ønsket vi å undersøke hvilken treningsfrekvens som var best for å øke kondisjonen, lungefunksjonen og hjertefunksjonen. Friske unge personer ble enten satt til å trene AIT 3 ganger per uke i 8 uker (moderat frekvens gruppen, MF) eller 8 ganger per uke i 3 uker (høyfrekvensgruppen, HF). Begge treningsperioder ble etterfulgt av en detreningsperiode uten trening i 8 uker. MF gruppen økte kondisjonen, lungefunksjonen og hjertefunksjonen progressivt under treningen og denne gikk gradvis tilbake under detreningen. HF gruppen fikk i utgangspunktet en tendens til nedgang i kondisjonen og en signfikant nedgang i lungefunksjon og hjertefunksjon. Dette normaliserte seg etter detreningsperioden. Konklusjonen på oppgaven er at høyintensiv aerob intervall trening er en trygg og effektiv metode for å øke kondisjonen, forbedre hjertefunksjonen og senke blodtrykket hos personer med høyt blodtrykk og blant friske eldre og yngre personer. For å unngå overtrening bør utrente personer trene med moderat frekvens, slik at kroppen får restituert seg mellom treningsøktene

This study compared the acute cardiopulmonary and metabolic effects of four high-intensity interval training (HIIT) protocols using varying intensities during the work and recovery periods. Eleven participants (5 males, 6 females) performed four, 20- minute HIIT protocols at a 1:1 "work:recovery" ratio on a cycle ergometer in random order. The work:recovery relative intensities, based upon previously determined maximum work rates, were: 80%:0%, 80%:50%, 100%:0%, and 100%:50%. Oxygen uptake, heart rate, blood lactate, and rating of perceived exertion were measured. Data were analyzed using a two-way, repeated measures ANOV A (p ≤ 0.05). Oxygen uptake and heart rate were expressed as a percentage of the peak values established during a prior graded exercise test. There were clear differences in physiological response between protocols. The 80:50 and 100:0 may produce the best combination of effects. The 100:50 produced the greatest physiological response, however, it may not be practical for the general population.

This study investigated the effects induced by 8 weeks of two high-intensity interval training (HIIT) protocols, 10-20-30 and 30-30 concepts, characterized by significantly different train-ing volume and intensity, on physiological parameters, running performance, body composition and psychophysiological stress of recreational divided into two groups: the 10-20-30 group performed two 10-20-30 sessions/wk and one con-tinuous training (CT)/wk, whilst the 30-30 group performed two 30-30 sessions/wk and one CT session/wk. VO2max, 1 km time, maximal aerobic speed (MAS), and body composition were evaluated before and after intervention. Internal load was measured through rating of perceived exertion (RPE). Both groups significantly improved running performance (1 km time: p = 0.04; MAS: p = 0.000001), aerobic fitness (VO2max: p=0.000002) and body composition (lean mass (kg) p=0.0001; fat mass ( %) p = 0.00005). RPE resulted significantly lower in the 10-20-30 group than in 30-30 group (10-20-30: 13.36 ± 0.28; 30-30:15.55 ± 0.21; p = 0.0002). Thus, the 10-20-30 group improved physiological parameters, performance and body composition, similar to 30-30 with significantly lower RPE values. These results suggest that in recreational runners the 10-20-30 training is effective in improving aerobic fitness and performance, with a lower subjective perception of effort, thus enhancing individual compliance and adherence to the pre-scribed training program

Aim The main aim of this study was to investigate the longitudinal effects on cycling performance using a polarized and periodized scheme that was highly supervised and controlled. The second aim was to investigate the effect of using Hyperoxia. The questions used to address the aim were: (1) How does overall performance change after a six-week training intervention? (2) What is the time-course and pattern of performance changes to the training scheme? (3) How does the performance change within the groups?   Method Nineteen male and female cyclists started the study (13 male and 6 female), however only 12 completed it (8 male and 4 female). The characteristics for the 12 subjects were:  age (year) 33.6 ± 6.8, height (cm) 177 ± 9.1, body mass (kg) 73.4 ± 8.8. Using a randomized, double blind design, the test subjects were divided in to hyperoxia (HOT) (n = 6) and normoxia (NOT) (n = 6) training groups.  Over a six week period the subjects followed a controlled polarized periodization that included 15 high intensity interval training (HIIT) sessions (3 x 8 min, 3 x 8 + 4 min, 4 x 8 min & 4 x 4 min) on maximal sustainable intensity (isoeffort) on a cycle ergometer. The dosage of oxygen was administered intermittently by the oxelerate device. A 20 min all out test was performed as pre- and post test.    Results The whole group (n = 12) increased mean power output (W) by 6.4 % (P = 0.002). The relative power output (W/kg) increased significantly 8.2 % (P = 0.0011). The HOT group (n = 6) increased their power output by 8.3 % (P = 0.028) and their relative power output increased by 9.4 % (P=0.011). The whole group (P = 12) significantly increased their VO2mean by 4.1 % (P = 0.03) and in the relative value by 5.4 % (P = 0.01) on the 20 min all out test. The whole group also had a significant increase in VO2peak of 3.7 % (P = 0.04). A very strong correlation could be found between the training data and the performance test.   Conclusions The training intervention was favourable for increasing performance and VO2peak in cycling. Usage of hyperoxia during the training intervention increases the performance.
Syfte och frågeställningar Huvudsyftet med denna studie var att undersöka de longitudinella effekter på prestation i cykling med hjälp av ett polariserat och periodiserat träningsupplägg som var väl övervakat och kontrollerat. Det andra syftet var att undersöka effekten av att använda hyperoxi. De frågeställningar som hjälpte att besvara syftet var: (1) Hur förändras prestationen efter en sex veckors träningsintervention? (2) Hur anpassar sig försökspersonerna till träningsschemat över tid?  (3) Hur förändras prestationen inom grupperna?   Metod 19 manliga och kvinnliga cyklister deltog i studien (13 manliga och 6 kvinnliga), 12 fullföljde hela studien (8 manliga och 4 kvinnliga). Karaktäristiken för de 12 försökspersonerna var: ålder (år) 33.6 ± 6.8, längd (cm) 177 ± 9.1, vikt (kg) 73.4 ± 8.8. Försökspersonerna delades in i hyperoxi (HOT) (n = 6) och normoxi (NOT) (n = 6), studien var dubbelblind. Under sex veckor följde försökspersonerna en kontrollerad polariserad periodisering som inkluderade 15 högintensiva intervallträningspass (HIIT) (3 x 8 min, 3 x 8 + 4 min, 4 x 8 min & 4 x 4 min) på högsta genomförbara intensitet (isoeffort) på cykelergometer. Doseringen av syre administrerades intermittent genom Oxelerate-enheten. Ett 20 min all-out test utfördes som för- och eftertest.   Resultat Hela gruppen (n = 12) ökade signifikant på prestationstestet (W) med 6.4 % (P = 0.002). Den relativa effekten (W/kg) ökade signifikant med 8.2% (P = 0.0011). HOT (n = 6) ökade signifikant på prestationstestet med 8.3% (P = 0.028) och den relativa effekten ökade med 9.4% (P = 0.011). Hela gruppen (n = 12) ökade signifikant i VO2medel under prestationstestet med 4.1 % (P = 0.03) och i det relativa värdet med 5.4 % (P = 0.01). Hela gruppen hade också en signifikant ökning av VO2peak med 3.7 % (P = 0.04). En mycket stark korrelation hittades mellan träningspassdata och prestationstestet.   Slutsats Träningsupplägget är gynnsamt för ökning av prestation och VO2peak i cykling. Användning av hyperoxi under träningsupplägget ökar prestationen.

In the last years it has been well demonstrated that Resistance Training is a good stimulus to hypertrophy, but also as a strategy against cardiovascular and metabolic diseases. But RT is composed by numerous variables that make difficult to understand the real effects of this kind of training. For this reason, the main aim of this dissertation was to study a specific method of RT, in which “intensity” is defined as the ratio between the load (%1RM) and the rest between the sets. Nowadays the lack of time is one of the major barrier to practise regular physical activity; so, it is important to find an exercise methodology that could be efficient and, at the same time, not too much long. HIIRT technique (High Intensity Interval Resistance Training) consist in 2 sets of 6 repetition to exhaustion at 80% 1RM, 20” rest, how many reps the subjects are able o perform with the same load, 20” rest and another set. The aim of this research was to understand the effects of HIIRT technique on the health and wellness of people, starting from cellular analysis to muscular performance responses. The research program was divided in four phases. In the first experimental part we aimed to study the acute signalling response on three different kind of exercise: Traditional Resistance Training (TRT), High Intensity Resistance Training (HIIRT) e High Intensity Training (HIT). The first two training represent a different intensity of RT, while the last one, is an aerobic training. 16 subjects participated at the study. Biopsies from the vastus lateralis were taken one week before training sessions (pre), immediately after, 6 hours after and 24 hours after training. Blood pressure and heart rate responses were also monitored during exercise. No significant differences were found at any time points in ribosomial protein of S6 and 4EBP1, while HIIRT seems to increase Akt activation and TRT ERK 1/2 signalling. TRT showed a similar oxidation pathway activation (AMPK, ACC and PCG-1) to HIT; whilst HIIRT technique seems to have only some effects close to the end of exercise. No differences were found between RT groups in blood pressure and heart rate responses. In the second experimental we considered the effects of the same RT protocols during 8 weeks of training in 20 young subjects. We assessed blood and hormonal parameters, body composition, strength, VO2max and resting energy expenditure before and after the training period. HIIRT technique improved maximal strength and muscle’s endurance but didn’t affect body composition or resting metabolism. In the third experimental phase we studied HIIRT technique on the elderly. 35 old subjects took part to the study, and 23 of those, finished the program. The experimental design was 6 months long: in the first 4 months all subjects performed the same progressive RT protocol, then they were divided in TRT and HIIRT groups. We evaluated strength, body composition and blood parameters. At the end of the experiment no difference in strength improvement were found; the muscle mass showed no significant improvement in both group; anabolic hormonal blood concentration (IGF-1; GH; testosterone) decreased in both training groups while lipoprotein values appeared to improve more in HIIRT than in TRT. Finally, we compared HIIRT technique with another high intensity method called pyramidal (PYR) on muscle damage indexes in 6 bodybuilders. We assessed Creatin Kinase (CK), Total Cholesterol (CHOL TOT), Blood Lactate (LAT) and “delayed onset muscle soreness” (DOMS) after a single bout of training. Blood samples were collected at baseline, after 2 and 48 hours after training. No differences were found in CK value, while CHOL TOT significantly decreased only in HIIRT; blood lactate and DOMS were higher in PYR compared to HIIRT. These data seems to indicate that HIIRT induce greater muscle damage with less soreness perception. In conclusion, HIIRT technique might be a good solution to improve muscular strength because it is effective and it is well accepted by subjects. Anyway, it seems bee too much intense for elderly and, without a controlled diet, it could not be a good solution to improve body composition.
Negli ultimi anni sta sempre di più affermando il concetto che l’allenamento contro resistenza, o Resistance Training (RT), sia un ottimo stimolo anabolico, e che la sua pratica costante possa migliorare la composizione corporea, contrastare i rischi di patologie cardiovascolari o metaboliche. Tuttavia, la struttura del RT è molto complessa e prevede l’interazione di numerose variabili che rendono disomogenei i protocolli utilizzati in letteratura per descrivere gli effetti di questa metodica di allenamento. Per questo motivo, l’argomento su cui fa perno questa ricerca, è lo studio di una specifica metodica di RT, in cui l’intensità è stata definita come il rapporto tra il carico sollevato (%1RM) e la durata del recupero tra le serie dell’esercizio. In considerazione della frenesia che contraddistingue la vita nella società odierna, uno dei principali ostacoli alla pratica continua di esercizio fisico è la mancanza di tempo: a tale scopo sarebbe importante trovare metodiche di allenamento che possano essere efficaci e al contempo avere una breve durata. La metodica HIIRT (High Intensity Interval Resistance Training) consiste nell’eseguire 6 ripetizioni ad esaurimento con un carico pari a circa l’80% di 1RM, 20” di pausa, per poi richiedere nuovamente al soggetto di effettuare il massimo numero di ripetizioni che è in grado di sostenere con il medesimo carico, altri 20” di pausa e ancora una serie. Lo scopo di questa ricerca è comprendere gli effetti della metodica HIIRT sulla salute ed il benessere dei soggetti mediante un’analisi a 360°, che comprenda sia lo studio degli adattamenti cellulari che le risposte in termini di performance muscolare. A tale scopo il progetto di ricerca è stato suddiviso in quattro fasi. In una prima parte sperimentale abbiamo confrontato l’effetto in acuto sul signalling muscolare di tre differenti protocolli di allenamento: Resistance Training Tradizionale (TRT), High Intensity Resistance Training (HIIRT) e High Intensity Training (HIT). Le prime due tipologie rappresentano due differenti intensità di allenamento con sovraccarichi, la terza proposta è invece un esercizio di tipo aerobico. Per il progetto ho reclutato 16 soggetti i quali sono stati assegnati random ai tre differenti protocolli. Le biopsie muscolari mediante ago sottile, sono state effettuate una settimana prima di ogni allenamento, immediatamente dopo la seduta, a 6h e 24h di distanza. I soggetti sono stati inoltre monitorati durante l’allenamento per valutare la risposta pressoria e cardiaca ai differenti protocolli di RT. L’analisi del signalling ha evidenziato una preferenziale attivazione di Akt in HIIRT, mentre il gruppo TRT sembra attivare maggiormente ERK1/2, invece le proteine ribosomiali 4EBP1 e S6 hanno subito la medesima influenza. TRT e HIT attivano in modo similare le vie di ossidazione mitocondriale (AMPK, ACC e PCG-1), mentre HIIRT sembra avere solo un effetto limitato alle prime ore successive all’allenamento. Nessuna differenza significativa è stata evidenziata per la risposta pressoria o cardiaca tra le due tipologie di RT. Nella seconda fase sperimentale abbiamo considerato gli effetti degli stessi protocolli di RT effettuati per un periodo di 8 settimane. Abbiamo reclutato 20 soggetti di età compresa da 20 e 30 anni. Prima e dopo il periodo di allenamento sono state effettuate le analisi ematochimiche ed ormonali, DEXA, test di forza, VO2max, e metabolismo basale. Il protocollo HIIRT ha migliorato la forza e la resistenza muscolare ma non la composizione corporea dei soggetti ,né è riuscito ad aumentare il metabolismo basale. La terza fase sperimentale prevedeva lo studio della metodica HIIRT su una popolazione di anziani sedentari. Per il progetto ho reclutato 35 anziani di età superiore ai 60 anni, di cui 23 hanno concluso lo studio. La sperimentazione ha avuto una durata complessiva di 6 mesi. I soggetti hanno iniziato un medesimo protocollo di RT a carichi progressivi per 4 mesi e, dopo una valutazione dei risultati raggiunti, sono stati assegnati random ai due differenti protocolli (HIIRT e TRT). È stato valutato l’effetto dell’allenamento sull’espressione di forza, sulla composizione corporea e su alcuni parametri ematochimici ed ormonali. Al termine dell’esperimento abbiamo potuto confermare quanto sta già emergendo dalla letteratura, ovvero che protocolli troppo intensi di allenamento non sono la metodica più efficace in una popolazione anziana. Nello specifico abbiamo rilevato un miglioramento di forza paragonabile al protocollo a bassa intensità; non si sono apprezzate differenze di massa muscolare dall’analisi della composizione corporea mediante BIA; il profilo ormonale ha mostrato una diminuzione in entrambi i gruppi della concentrazione basale degli ormoni anabolici (IGF-1; GH; testosterone) mentre, le lipoproteine ematiche hanno risposto in maniera positiva all’allenamento HIIRT. Infine, abbiamo confrontato la metodica HIIRT ed un’altra metodica ad alta intensità, chiamata piramidale (PYR) su indici di danno muscolare. Per questo studio sono stati reclutati 6 soggetti con esperienza nel mondo del body building. La procedura sperimentale prevedeva l’analisi degli indici di danno muscolare quali Creatin Kinase (CK), Colesterolo totale (CHOL TOT) e Acido Lattico (LAT) in seguito ad una singola seduta dei due protocolli allenanti. I campioni ematici sono stati raccolti a riposo, immediatamente dopo l’esercizio, e a distanza di 2 e 48 ore. Le due tipologie di allenamento somministrate non sembrano influenzare in modo significativo i valori di CK, mentre vi è una diminuzione significativa del CHOL TOT (indice di danno muscolare) con la metodica HIIRT rispetto alla metodica PYR; vi è stato un maggior aumento del lattato con metodica PYR rispetto a quella HIIRT. La percezione della dolenzia muscolare è stata maggiore dopo PYR. Questi dati, sembrano dimostrare che, in atleti esperti, la metodica HIIRT induce un maggior danno muscolare ma una minor sensazione di fatica rispetto al PYR. In conclusione, la metodica HIIRT è una buona soluzione per aumentare la forza muscolare, ed è ben tollerata dai praticanti. Tuttavia è troppo intensa per soggetti anziani, e non efficace nel migliorare la composizione corporea se non accompagnata, probabilmente, da una dieta controllata.

Introduction: Impaired inhibitory control, one of the core executive functions, is common among individuals with mental illness. However, inhibitory control is essential for successful treatment and recovery. Inhibitory control is extremely vulnerable to developmental disruption during adolescence, a time when mental illness is first diagnosed. An acute bout of exercise has been shown to improve inhibitory control in healthy adolescents, however, to our knowledge there are no studies evaluating this effect in adolescents with mental illness. Purpose: The primary goal of this project was to examine the effect of an acute bout of high-intensity interval training on inhibitory control immediately, and 30 minutes following exercise in adolescents hospitalized for mental illness. The secondary goal was to assess the feasibility of using this type of exercise as an adjunct to current treatment. Methods: Participants were recruited through the inpatient mental health unit at the Children’s Hospital of Eastern Ontario. They performed exercise and control conditions in a randomized, counterbalanced manner. The Colour-Word Stroop Task was assessed pre, post, and 30-minutes-post on both days. The exercise condition included a 12 minute HIIT circuit, consisting of body weight exercises performed in a 1:1 work to rest ratio. The control condition involved reading magazines. Repeated-measures ANOVA evaluated changes in Interference Cost, the reaction time cost of responding to trials where the ink and colour do not match, and overall accuracy. Feasibility was assessed through recruitment and completion rates, as well as changes in affect and acceptability of the high-intensity interval training. Results: There was a significant interaction between condition and time for the Interference Cost measure, F(1.6,43.3)=13.6, p<.0001, η2=.34. Interference Cost was similar for both conditions at baseline (Mdiff = 12.4±11.11, p=.28). Interference Cost was significantly reduced immediately (Mdiff = 78.8±14.91, p<.001) and 30-minutes post-exercise (Mdiff = 59.6±15.14, p=.001) compared to control. Response accuracy did not differ by time, F(2,54)=.14, p<=.87, η2=.01 nor condition, F(1,27)=2.25, p=.15, η2=.08. After exercise, participants increased positive affect (mean difference = 4.3±8.09, p=.009) and were willing to perform the exercise before therapy sessions (rating = 6.4±2.75 out of 10). Conclusion: These findings suggest that high-intensity interval training could be used to improve inhibitory control in adolescents with mental illness, which has the potential to enhance the efficacy of their treatment. Future research should determine the impact of individual factors, such as diagnosis, medication, age of illness onset, length of hospitalization, and treatment history, on inhibitory control improvement after exercise.

Thesis (MScSportSc)-- Stellenbosch University, 2013.
ENGLISH ABSTRACT: There is a growing concern in South Africa and worldwide about the global epidemic of obesity and overweightness among the general population. Obesity mediates the pathogenesis of pathological conditions and is associated with a poor quality of life, high morbidity and mortality rates and a huge burden on an individual’s and the health system’s infrastructure and finances. The answer to this rising epidemic is weight loss. Endurance training has been shown to induce weight loss however, people usually cite lack of time as a barrier to meaningful participation in exercise programmes. High intensity interval training (HIIT) therefore emerges as a potential solution to these barriers as it takes a relatively short period of time compared to endurance training. Despite the differences in exercise durations the most cogent advantage is that HIIT elicits not just similar, but even superior central and peripheral adaptations. The central and peripheral adaptations have been shown to enhance weight loss, improve blood lipids and glucose levels, as well as decreasing blood pressure. The challenge facing exercise physiologists is to find the optimal exercise intensity and duration of HIIT bouts which would be time efficient, safe and well tolerated by overweight and obese people. The shortcomings of literature are that most HIIT studies have focused on healthy, overweight and obese men and these studies cannot be extrapolated to women who have been shown to respond differently to training. Moreover, other interventions investigating the effects of HIIT in women and men have been longer term rather than short term interventions. In order to fill the gaps in the literature, the main aim of this study was to investigate the training and detraining effects of a short-term HIIT programme on selected health-related measures in young overweight and obese women. To this end, a non-random sample of 20 overweight and obese women (aged 18-25) volunteered to participate in this study. Selected health-related outcomes were measured prior to training. The pre-training testing was followed by the HIIT intervention which was two weeks and consisted of six sessions using the 10 – 15x1 minute running at 90% HRmax which was separated by one minute active recovery periods at 50-60% of HRmax. The HIIT intervention was followed by a post test in which baseline measurements were repeated. This was then followed by a two week detraining period and follow up testing. The main finding of this study was that a period of two weeks of HIIT can elicit adaptations that can lower the risk profiles of young overweight and obese women. The results showed a statistically significant decrease in body mass (1.6%, p = 0.001), fat mass (3.7%, p = 0.001) and waist circumference (4.8%, p = 0.001), and an increase in lean mass of 1.9% (p = 0.001). There was also a decrease in blood glucose (11%, p = 0.001), total cholesterol (10.4 %, p = 0.01), systolic (3.4%, p = 0.001) and diastolic blood pressure (5.8%, p = 0.001) levels. Finally there was a statistically significant increase in relative VO2max and exercise capacity after the HIIT The follow-up testing after two weeks of detraining shows that the metabolic adaptations that were achieved by the HIIT protocol are relatively lasting or are at least not completely reversed. The weight loss induced by HIIT is important in that it is the major target in lowering the prevalence of overweightness and obesity. The HIIT protocol in this study emerges as a time efficient strategy in eliciting positive adaptations in clinical populations and healthy people. Moreover these findings suggest that 10 minute and 15 minute HIIT work bouts at near-maximal intensities are possibly the minimum amount of training that is needed to induce significant weight loss and other positive health-related outcomes.
AFRIKAANSE OPSOMMING: Daar bestaan ʼn toenemende besorgdheid in Suid-Afrika en wêreldwyd oor die globale epidemie van obesiteit en oorgewig onder die algemene bevolking. Obesiteit fasiliteer die patogenese van verskeie siektetoestande en word met ʼn swak kwaliteit lewe, hoë morbiditeit en mortaliteit en ʼn geweldige las op ʼn individu en die gesondheidsowerhede se infrastruktuur en finansies geassosieer. Een van die antwoorde op hierdie stygende epidemie is gewigsverlies. Dit is reeds gewys dat uithouvermoë oefening saam met ʼn kalorie beperkende dieet gewigsverlies in die hand werk. Mense dui egter ʼn tekort aan tyd as ʼn hindernis tot betekenisvolle deelname aan ʼn oefenprogram aan. Hoë intensiteit interval inoefening (HIIO) is dus ʼn potensiële oplossing tot hierdie hindernis aangesien dit in vergelyking met uithouvermoë inoefening in ʼn relatiewe korter periode van tyd uitgevoer kan word. Afgesien van die verskille in inoefenperiodes is die mees logiese voordeel dat die HIIO nie net soortgelyke nie, maar self beter sentrale en periferale fisiologiese aanpassing voortbring. Die sentrale en periferale aanpassing verhoog gewigsverlies, verbeter bloedlipiedes en glukose vlakke, en veroorsaak ʼn afname in bloeddruk. Alhoewel ʼn aantal studies die voordele van HIIO by jonger en ouer populasies aandui, is baie min studies op vrouens uitgevoer. Bevindinge kan nie noodwendig na vrouens ekstrapoleer word nie omdat hulle dikwels verskillend op inoefening as mans reageer. Dit is ook nie bekend of ʼn kort HIIO intervensie ʼn betekenisvolle impak op oorgewig en vetsugtige vrouens sou hê nie, asook hoe blywend enige veranderinge sou wees nie. Die hoofdoel van hierdie studie was dus om die inoefening- en die geen-inoefening effekte van ʼn korttermyn HIIO program op geselekteerde gesondheidskenmerke in jong oorgewig en vetsugtige dames te bepaal. ʼn Nie-ewekansige steekproef van 20 oorgewig en vetsugtige vrouens (18-25 jaar) het vrywillig ingestem om aan hierdie studie deel te neem. Geselekteerde gesondheidskenmerke is voor die aanvang van die inoefening gemeet. Die HIIO intervensie het twee weke geduur en het uit ses sessies bestaan (10 – 15x1 minuut draf by 90% HSmaks en een minuut aktiewe herstel by 50-60% HSmaks). Die HIIO intervensie is deur ʼn na-toets gevolg waarin basislyn metings herhaal is. Dit is deur ʼn twee weke geen-inoefening periode en opvolgtoetse opgevolg. Die hoofbevinding van hierdie studie was dat ses sessies van HIIO fisiologiese aanpassings na vore gebring het wat die risiko profiele van jong oorgewig en vetsugtige vrouens verlaag het. Daar was statisties betekenisvolle afnames in liggaamsmassa (1.6%, p < 0.001), vetmassa (3.7%, p < 0.001) en heupomtrek (4.8%, p < 0.001) en ʼn toename in vetvrye liggaamsmassa van 1.9% (p < 0.001). Daar was ook ʼn afname in bloedglukose (11%, p < 0.001), totale cholesterol (10.4 %, p = 0.01), sistoliese (3.4%, p < 0.001) en diastoliese bloeddruk (5.8%, p < 0.001). Daar was ook statisties betekenisvolle verbeteringe in relatiewe VO2maks en oefeningtoleransie na inoefening. Die opvolgtoetse na twee weke van geen-inoefening het getoon dat metaboliese aanpassings wat deur die HIIO bereik is, relatief blywend van aard was of ten minste nie totaal omgekeerd was nie. Die gewigsverlies wat deur die HIIO veroorsaak was is belangrik in die sin dat dit die hoofdoelwit aanspreek om die voorkoms van oorgewig en vetsugtigheid te verminder. Die studie suggereer verder dat 10 – 15 minute HIIO werksessies, by naby maksimale intensiteite, moontlik die minimum hoeveelheid inoefening is wat benodig word om betekenisvolle gewigsverlies en ander positiewe gesondheidskenmerke te bereik.

Diabetes is recognised as the world’s fastest growing chronic condition. The prevalence of early-onset type 2 diabetes (diagnosed with type 2 diabetes before the age of 45 years) has risen sharply over the past decades, with lack of physical activity and excessive sedentary behaviour being important contributing factors. Early-onset type 2 diabetes is associated with earlier onset of diabetes-related complications, including diabetic peripheral neuropathy and brachial arterial stiffness. Exercise is a well-established, first-line management strategy for type 2 diabetes, but there is limited high quality research on whether people with early-onset type 2 diabetes respond to exercise in the same way as people with late-onset type 2 diabetes. The aim of this thesis was to investigate the impact of high-intensity interval training (HIIT) on nerve function, endothelial function, aerobic fitness, physical activity, quality of life, and attitude to exercise through the use of qualitative and quantitative methodologies in people with early-onset type 2 diabetes. The thesis also examined how people with early-onset type 2 diabetes differed (at baseline) from matched controls without diabetes in the above outcome measures. The first study in the thesis is a systematic review (Chapter 2), that demonstrated aerobic exercise can be effective in improving nerve function in people with type 2 diabetes. The second study in the thesis is a pilot randomised controlled trial. (Chapters 3, 4) An eight-week HIIT program was carried out among eleven people with early-onset type 2 diabetes. The study found participants had significant improvement in aerobic fitness after the HIIT program, with little change in glycated haemoglobin, nerve function, endothelial function, physical activity, attitude to exercise, or quality of life. The qualitative component of the study identified many barriers that hindered participants’ engagement in diabetes services and regular exercise, and revealed a boom bust exercise history. A cross-sectional study (Chapter 6, 7) compared participants with early-onset type 2 diabetes to age-, gender-, ethnicity- and body mass index-matched control participants without diabetes. There was no significant difference between the two groups in nerve function and aerobic fitness. HbA1c was significantly correlated with a variety of nerve and anthropometric measures, and VO2peak was significantly correlated with a variety of nerve and endothelial function outcome measurements. Participants with early-onset type 2 diabetes demonstrated lower level of physical activity and autonomous regulation (a component of self-determination theory) of exercise engagement when compared to control participants. Level of physical activity was correlated with autonomous regulation. Overall, the findings from this thesis demonstrated HIIT was safe, feasible and acceptable to offer to people with early-onset type 2 diabetes who had no pre-existing complications. A behavioural intervention might be needed to promote long-term exercise engagement and maintenance. Other impacts of HIIT in this cohort need to be confirmed by larger trials including people with different severity of complications.

Thesis (MScSportSc)--Stellenbosch University, 2013.
ENGLISH ABSTRACT: There are extensive literature on the PEH response after acute and chronic aerobic and resistance exercise, as well as a few studies on concurrent and water exercise. However, there is comparatively little evidence that high intensity interval training (HIIT) elicits similar post exercise blood pressure reductions (PEH) compared to other types of exercise. Furthermore, it is difficult to quantify the magnitude of the hypotensive response following these exercises, due to variations in exercise protocols in terms of intensity and duration. Both these training variables are considered important determinants of the magnitude and duration of the PEH response. The current study determined the magnitude of the PEH response after an acute bout and six sessions of HIIT, and the effects after two weeks of detraining in overweight/obese young women. Twenty young women (aged 21 ± 2 years) volunteered for the study. All the subjects were normotensive (SBP: 119.2 ± 5.6 mmHg and DBP: 78.8 ± 4.1 mmHg). Subjects performed six sessions of HIIT within two weeks and detrained for two weeks. SBP, DBP, MAP and HR were monitored during seated recovery after exercise for 60 min to determine the change from resting values. The overall outcome showed that an acute HIIT session resulted in a reduction of 2.9 mmHg in SBP which approached near clinical significance, while six sessions of HIIT caused a clinically significant reduction of 5.3 mmHg; this response was almost totally reversed after detraining. There were no clinically significant reductions in DBP after the acute or six sessions of HIIT (1.7 and 2.7 mmHg, respectively). However, a clinically significant hypotensive response of 3.9 mmHg was sustained after detraining following the maximal exercise capacity test. MAP also reduced by a magnitude of 2.3 and 5.6 mmHg, respectively, after the acute bout and six sessions of HIIT, and detraining values were still 2.9 mmHg lower than resting values and approached near clinical significance. The results indicate that both an acute bout and six sessions of HIIT elicited a meaningful PEH response. However, the six sessions of HIIT caused a clinically significant reduction which was approximately twice the acute session. Likewise, detraining showed clinically significant effects in DBP and MAP, but SBP returned to near baseline values. This suggests that in only two weeks, the accumulated effects of six sessions of HIIT elicited a greater hypotensive response than after an acute session of HIIT.
AFRIKAANSE OPSOMMING: Daar is omvattende literatuur oor die post-oefening hipotensie (POH) na afloop van akute en kroniese aërobiese en weerstandsoefeninge, asook enkele studies oor gelyktydige krag- en uithouvermoë- en wateroefeninge. Daar is egter relatief min bewyse dat hoë intensiteit interval oefening (HIIO) soortgelyke post-oefening afnames in bloeddruk (POH) in vergelyking met ander tipes oefening veroorsaak. Voorts is dit moeilik om die omvang van die hipotensiewe respons na afloop van oefening te kwantifiseer, hoofsaaklik as gevolg van die variasies in oefeningprotokolle in terme van intensiteit en tydsduur. Beide hierdie inoefeningveranderlikes word as belangrike determinante van die omvang en die tydsduur van die POH respons beskou. Die huidige studie het die omvang van die POH respons na ʼn akute sessie en ses sessies HIIO, en die gevolge na afloop van twee weke se nie-inoefening (“detraining”) by oorgewig/vetsugtige jong dames, bepaal. Twintig jong dames (ouderdom 21 ± 2 jaar) het vrywillig ingestem om aan die studie deel te neem. Al die deelnemers was normotensief (SBD: 119.2 ± 5.6 mmHg en DBD: 78.8 ± 4.1 mmHg). Die deelnemers het ses sessies HIIO binne twee weke voltooi en het daarna vir twee weke geen inoefeningsessies gehad nie. SBD, DBD, GAD en HS is tydens ʼn sittende herstelfase vir 60 minute gemonitor om die verandering vanaf rustende waardes te bepaal. Die algehele uitkoms toon dat ʼn akute HIIO sessie ʼn afname van 2.9 mmHg in SBD tot gevolg gehad het wat aan kliniese betekenisvolheid grens, terwyl ses sessies van HIIO ʼn klinies betekenisvolle afname van 5.3 mmHg veroorsaak het; hierdie respons wat bykans volledige omgekeerd na die twee weke met geen inoefening. DBD het geen kliniese betekenisvolle afname na afloop van die akute of ses sessies van HIIO getoon nie (1.7 en 2.7 mmHg, respektiewelik). ʼn Klinies betekenisvolle hipotensiewe respons van 3.9 mmHg is egter gevind na die geen inoefeningsperiodes. GAD het ook met ʼn omvang van 2.3 en 5.6 mmHg, respektiewelik, verminder na afloop van die akute sessie en ses sessies van HIIO. Die geen inoefening waardes was steeds 2.9 mmHg laer as die rustende waardes en het aan kliniese betekenisvolheid gegrens. Die resultate toon dat beide ʼn akute sessie en ses sessies van HIIO ʼn betekenisvolle POH respons ontlok het. Ses sessies van HIIO het egter ʼn klinies betekenisvolle afname, wat ongeveer twee keer soveel as die afname van die akute sessie was, veroorsaak. In dieselde lig het ʼn twee weke geen inoefeningsperiode steeds klinies betekenisvolle veranderinge in DBD en GAD getoon, maar SBD het tot naby aan die basislyn waardes teruggekeer. Hierdie resultate suggereer dat in slegs twee weke die geakkumuleerde effekte van ses sessies van HIIO ʼn groter hipotensiewe respons as na ʼn akute sessie van HIIO ontlok het.

Master of Science
Department of Kinesiology
Craig A. Harms
Subjects with prehypertension are at risk for developing hypertension (HTN). Hypertension is associated with low-grade systemic inflammation (LGSI). Aerobic exercise training (ET) is a proven means to reduce both blood pressure and LGSI in healthy and diseased subjects. Recently, high intensity interval training (HIIT) has been show to elicit similar cardiovascular and metabolic adaptations as ET in healthy and at-risk populations in a more time efficient manner. Therefore, we hypothesized that HIIT would elicit greater reductions in blood pressure and LGSI than ET. Twelve pre-hypertensive subjects (systolic blood pressure 127.0 ± 8.5 mmHg; diastolic blood pressure 86.2 ± 4.1 mmHg) were randomly assigned to an ET group (n=5) and a HIIT group (n=7). All subjects performed an incremental test to exhaustion (VO2max) on a cycle ergometer prior to, after 4 weeks, and after 8 weeks of training. Resting heart rate and blood pressure were measured prior to and three times a week during training. LGSI was measured via high-sensitivity C-reactive protein (hs-CRP) prior to, after 4 weeks and after 8 weeks of training. ET subjects performed an eight week exercise training program at 40% VO2 reserve determined from the VO2max test, while HIIT subjects performed exercise at 60% peak power determined from the VO2max test. ET group trained four days/week while HIIT trained three days/week. ET exercised for 30 minutes continuously at a constant workload and cadence of 60 rpm while HIIT performed a protocol on a 1:1 work-to-rest ratio at a constant workload and cadence of 100 rpm. Both groups showed similar (p<0.05) decreases in mean arterial (ET = -7.3%, HIIT = -4.5%), systolic (ET = -6.6%, HIIT = -8.8%), and diastolic (ET= -9.7, HIIT= -8.2%) blood pressure. HIIT decreased in LGSI (-33.7%) while ET did not change LGSI (p>0.05). VO2max increased ~25% with both HIIT and ET with no differences (p>0.05) between groups. These data suggest both HIIT and ET similarly decreased resting blood pressure and increased VO2max while HIIT was effective in decreasing LGSI in subjects who were pre-hypertensive.

This study examined whether a high-intensity interval (IT) or a continuous steady-state (CT) exercise training program had the greatest effect on fat oxidation rates and fat mass loss in a population of untrained overweight and obese females. Thirteen female subjects (VO2peak 30.6 ± 1.29 ml.kg.min-1, BMI 29 ± 0.79, fat mass [FM] 33.3 ± 2.09 kg) were randomly assigned to either a CT (exercise at the relative intensity that elicits the maximal fat oxidation rate [FATmax] ) or an IT (intervals alternating 5 minutes at 40% and 85% VO2peak) training group that exercised approximately 1 hour, 3 days.week-1 for 10 weeks. Body composition assessments, peak oxygen uptake (VO2peak), FATmax and plasma free fatty acid (FFA) concentrations were examined pre- and post-training using dual-energy X-ray absorptiometry (DEXA), ParvoMedics gas analysis system and FFA half micro tests (Roche Diagnostics). No significant differences were found post-training in body weight (kg), body fat (%), fat-free mass, or fat mass (P>0.05). The relative exercise intensity that elicited FATmax was significantly increased from 35.3 ± 2.55% to 44.7 ± 3.56% in the IT group post-training (P <0.05). The maximal fat oxidation rate was determined at a higher relative exercise intensity after 10 weeks of a IT program compared with a CT program, which resulted in longer durations of fat oxidation during submaximal exercise bouts. These data suggest that an IT program induces a greater increase in the relative exercise intensity that elicits maximal fat oxidation after 10 weeks of training compared to a CT program in this population. Although body composition and FATmax were not altered, it is possible that through training induced metabolic adaptations from the IT program, intramuscular triacylglyceride (IMTG) contributions to fat oxidation at a given steady-state work rate could be increased post-training.

Abstract BACKGROUND: Arthritis and other rheumatic conditions are a growing health problem, in terms of prevalence, disability and cost. Rheumatism is classified as chronic, systemic, and autoimmune diseases. Major symptoms are synovial inflammation and swollen joints, autoantibody production, deformation of cartilage and bone structures, and systematic features such as cardiovascular, pulmonary, psychological and skeletal disorders. The mortality rate in patients with rheumatoid arthritis (RA) is 1.5 – 1.6 compared to that of the general public, and cardiovascular diseases (CVD) account for 40-50% of the deaths. In addition, a five-fold increased CVD-risk, was observed in female patients with RA who were diagnosed at a young age. Scientific studies have shown that aerobic interval training of high intensity is effective in improving general physical status and cardiovascular health, but is not yet used as a treatment option for people with rheumatism. The aim of the present study was to find out if ten weeks of high intensity interval training was well tolerated by people with rheumatic diseases, and if it would improve activity of the disease, quality of life, and traditionally risk factors for cardiovascular diseases. METHODS: Eighteen women with RA and juvenile idiopathic arthritis (JIA), aged 20-50 years, were recruited to this cross-over study. Participants performed supervised interval training 2 times a week for 10 weeks on a spinning bike. The exercises consisted of four 4-minute intervals at ~90% of maximal heart rate (HRmax), interspersed with 3 minute recovery periods at ~70% of HRmax. Maximal oxygen uptake (VO2max), HRmax, one minute heart rate recovery (1-minHRR), blood pressure, body composition, blood analysis, molecular status (TNF-&#945;, Interleukin-6 (IL-6), Human Cartilage Oligometric Matrix Protein (COMP) and Pentraxin-3), disease activity status, and questionnaires (Visual analogue scales (VAS), Modified Stanford Health Assessment Questionnaire (MHAQ), and SF-35) were measured before and after both exercise and control periods. Statistical analyses were performed using the software program SPSS. RESULTS: As a consequence of high intensity interval training (HIIT), the results showed that; VO2max increased by 12.2% (p < 0.001), 1-minHRR decreased by 3.7% (p = 0.02), BMI, body fat, visceral fat and waist circumference decreased by 1.2% (p= 0.04), 1.0% (p= 0.05), 0.2% (p= 0.08) and 1.6% (p=0.004), respectively, whereas muscle percentage increased by 0.6% (p=0.03). Significant differences were found for serum glucose (increased 6.3%, p=0.05), haemoglobin (decreased 2.2%, p= 0.03) and ferritin (decreased 24.0%, p= 0.006). High sensitive CRP (hsCRP) level decreased by 41.9% (p= 0.08). IL-6 mRNA increased by 32.6% (p=0.02), COMP levels increased by 12.6% (p=0.06), and Pentraxin-3 levels decreased by 27.3% (p=0.14). MHAQ score decreased by 24.6% (p=0.13), self reported global health VAS-score decreased by 33.8% (p=0.13), and pain VAS-score decreased by 34.8% (p=0.12). The participants scored themselves better for bodily pain and emotional role in SF-36. CONCLUSION: Ten weeks of HIIT was well tolerated by females with RA and JIA, and improved the disease activity, quality of life, and traditionally risk factors for cardiovascular diseases. HIIT might be recommended as a safe treatment for persons with RA and JIA.

Introduction Type 1 diabetes is characterised by insulin deficiency, however the ‘double diabetes’ phenotype of type 1 diabetes with insulin resistance and/or metabolic syndrome is becoming increasingly recognised, especially given rising global obesity rates. The effects of exercise on metabolic health have not been adequately studied in people with type 1 diabetes, and exercise-related hypoglycaemia is a major barrier. Aims This thesis aimed to examine the prevalence of metabolic syndrome in adults with type 1 diabetes, and its association with diabetes complications. The safety and benefits of high-intensity interval training (HIIT) on glycaemic control, cardiometabolic measures and liver fat were studied in people with type 1 diabetes and metabolic syndrome features. Methods Three related studies were conducted. Firstly, a cross-sectional study examined the prevalence of metabolic syndrome in type 1 diabetes, and its age-related association with diabetes complications. Secondly, the safety of HIIT in type 1 diabetes on exercise-related hypoglycaemia was examined in a pilot study using continuous glucose monitoring. Thirdly, a randomised controlled trial examined the effect of HIIT on HbA1c, cardiometabolic health and liver fat in adults with type 1 diabetes and overweight or obesity. Results Metabolic syndrome was common in adults with type 1 diabetes and was associated with a higher prevalence of diabetes complications, with the greatest impact at a younger age. HIIT performed with diabetes self-management strategies was not associated with increased exercise-related hypoglycaemia over 24 hours. In the randomised controlled trial, 12 weeks of HIIT did not significantly reduce HbA1c compared with control (-0.53% vs -0.14%, p=0.08). After 24 weeks, HIIT resulted in improvements in HbA1c, cardiorespiratory fitness and body composition compared with baseline. There was a favourable trend towards liver fat reduction with HIIT. Conclusions Metabolic syndrome can identify a high-risk population of type 1 diabetes, who may benefit from interventions targeting insulin resistance and cardiometabolic risk. This thesis provides novel evidence that HIIT can be performed safely, and can improve glycaemic control and cardiometabolic health in people with type 1 diabetes and metabolic syndrome features.

碩士
長榮大學
運動競技學系(所)
106
This study explores changes in exercise intensity at different points in time in the HIIT training process. Twelve university-level male rugby athletes were subjects who underwent high-intensity interval training, with full-strength sprint run as the exercise model, with 15 seconds of exercise and 30 seconds of rest, with 8 cycles. Throughout the process, they wore the POLAR watch to record their heart rate, and RPE was recorded at each rest time. In addition, blood was taken to detect blood lactic acid during the rest times of the second, fourth, sixth, and eighth cycles and at three, five, ten, fifteen, and thirty minutes after training. Descriptive statistics and dependent sample one-way ANOVA was used to test the blood lactic acid, %HRR, and RPE values derived at different points in time during high-intensity interval training; the level of significance was α = .05. Study results showed that during training, minimum blood lactic acid was 4.19 ± 0.66 mmol/L, maximum blood lactic acid was 7.74 ± 0.94 mmol/L (eighth trip, p <.05), while the mean value was 6.14 ± 1.48 mmol/L. After training, minimum blood lactic acid was 4.36 ± 1.51 mmol/L, maximum blood lactic acid was 8.29 ± 0.90 mmol/L (seventh trip, p <.05), while the mean value was 6.84 ± 1.53 mmol/L. Minimum heart rate was 123.08 ± 10.71 beats, maximum heart rate was 162.17 ± 10.39 beats, mean value was 150.99 ± 13.30 beats. Minimum %HRR was 47.52 ± 6.93%HRR, maximum %HRR was 74.83 ± 6.96%HRR (seventh trip, p <.05), while the mean value was 66.99 ± 9.29%HRR. Minimum RPE was 12.83 ± 0.83, maximum RPE was 17.08 ± 0.51 (eighth trip, p <.05), and the mean value was 15.24 ± 1.41. 1. Conclusion: High intensity interval training can stimulate the runner's energy system effectively. Through short-term, high-intensity exercise stimulation, the aerobic exercise capacity of runners should be effectively improved without consuming a large amount of training time. The result of this study found that the HIIT with eighth trips training will more in line with metabolism needs of the game. Conclusion: 1. Results of this study proved that in the process of HIIT, blood lactic acid continued to be produced, reaching the effects of high-intensity training. It also satisfies the competition intensity needs similar to the sporting model and should be considered an effective training model. 2. Results of this study proved that in the process of HIIT, with continuously elevating heart rate and %HRR, reaching peak value at the seventh trip, and the runner reached the plateau stage in the sixth trip. Response to high-intensity training was demonstrated in terms of both heart rate and %HRR results, which also meet the needs of actual competitions. 3. Results of this study proved that in the process of HIIT, RPE continues to increase, reaching the peak value at the eighth trip, and the RPE response was slightly higher than the actual response in heart rate; this may have been caused by repetitive stimulus of high-intensity training. To meet the demand of energy metabolism in contest, it is recommended to have the training arranged till the eighth trip at least. We suggested that the further study in HIIT can focus on the effect of different rates of exercise recovery time and different sets.

碩士
國立體育大學
教練研究所
97
Purpose: To compare the effect of high-intensity interval training (HIT) and moderate-intensity continued training (MCT) by canoe ergometer on aerobic capacity and exercise performance in canoeists. Methods: Twenty-four national canoeists (age: 18.4 ± 1.9 yrs, height: 172.4 ± 7.7 cm, weight: 70.3 ± 9.8 kg) participated to this study. All subjects completed the graded exercise test (GXT) on canoe ergometer to measure the VO2peak, anaerobic threshold (AT), heart rate (HR) and the time of exhaustion on pre-, mid- and posttraining. Pre- and posttraining, time trial of 1000 m, 500 m and 200 m on canoe ergometer were performed. Subjects were divided into three groups of high-intensity training (HIT) group, moderate-intensity continued training (MCT) group and traditional training (TDT) group according to the performance of 1000 m time trial. The training program proceed 3 times per week for 4 weeks. HIT group included 7 repeated of 2-min intervals training at power of 90% VO2peak and separated by 1 minute rest. MCT group performed continuous training at power of 65% VO2peak for 20 min. TDT group performed a traditional endurance training in low-intensity for 90 min. One-way ANOVA with repeated-measures were used to compare the VO2peak, AT and HR at pre-, mid- and posttraining within groups. Paired t – test were used to compared the performance of 1000 m, 500 m and 200 m at pre- and posttraining. All variables at mid - and posttraining among groups were compared by ANCOVA with covariate of variables at pretraining. Result: The VO2peak in HIT and MCT groups significantly increased after 2 weeks training (p<0.05). AT in MCT group significant higher than in TDT group, after 4 weeks training, HR in MCT group significant lower than HIT and TDT groups (p<0.05) at the intensity of 75 W in GXT. The performance of 1000 m significant improvement in three groups, time trial of 500 m had significant improved in MCT and TDT groups. However, performance of 200 m improved only in HIT group (p<0.05). Conclusions: high-intensity interval training and moderate-intensity continued training by canoe ergometer results in greater efficiency and improvement than traditional training. Moderate-intensity continued training had a better improvement in aerobic capacity and performance of 1000 m and 500 m. However, high-intensity interval training is a better way for improve the performance of 200 m on canoe.

碩士
高雄醫學大學
運動醫學系碩士在職專班
105
Regular exercise brings many benefits for central nerve system (CNS), for example, promote learning and memory effect, reduce the incidence of neurodegenerative diseases, as well as protection from nerve tissue damage.Brain- derived neurotrophic factor (BDNF) will secrete after exercise, which plays an important role in this process. BDNF is a neurotransmitter, that can enhance learning and memory by stabilizing dendritic spines, and activate neural stem cells to implement neurogenesis. High intensity interval training (HIIT) can quickly improve the effect of aerobic metabolism in skeletal muscle, providing an effective exercise intervention mode for prevention and treatment of metabolic syndrome. However, HIIT could easily lead to tissue damage, whether HIIT would hurt the CNS functions, there is no relative research presently. Because of the great increasing of Arc (activity-regulated cytoskeleton-associated protein) during learning and memory process in hippocampus of brain, the study shows the amount of Arc as a biochemical indicator of learning and memory function. The aim of study is to confirm whether the short-term HIIT injured the hippocampal function on rats. For this purpose, the male rats were divided into control (C) and HIIT groups (H), HIIT group will be trained for 14 days, then conducted the Barnes Maze to induce spatial learning on hippocampus, and after that, remove the hippocampus for protein electrophoresis to analysis the amount of Arc. The results showed that the HIIT group have worse learning ability for Barnes Maze test, and less amount of Arc in hippocampus compared with control group. In addition, the amount of BDNF in serum that examined by ELISA, there was no difference between two groups, however, it showed higher concentration of BDNF in hippocampus in HIIT group. This study revealed that short-term HIIT will damage the function of hippocampus, and then influence the ability of spatial learning, but which damage is not related with BDNF.

The purpose of this study was to determine the effect of high intensity interval training (HIIT) on post traumatic stress disorder (PTSD) and to compare the results of HIIT to a short, deep breathing session (BRTH) that is commonly used to manage PTSD symptoms. Previous research has demonstrated a positive effect of exercise on PTSD and related mental health concerns. Seven volunteers (six females and one male) participated in this study. All participants completed two groups of sessions, one comprised of three HIIT sessions and one of three BRTH sessions. Each group of sessions took place over approximately ten days, with a 4-week washout period between the two protocols. The HIIT sessions each involved eight sets of a work rest ratio of 20-second exercise to 10-second rest, with a 60-second break between the fourth and the fifth set for a total of 5 minutes. The BRTH sessions involved the use of an established 5-minute deep breathing PTSD therapy protocol. PTSD symptoms were measured using the PTSD Checklist (PCL). PCL measures were taken before (pre-test) and after (post-test) the intervention. Within the HIIT intervention, mean post-test Total PCL scores were significantly reduced compared to pre-test scores (p < 0.005), while BRTH scores did not significantly change. Two subscales in the PCL, Intrusion and Avoidance were also significantly reduced (p < 0.0005) following HIIT but not BRTH. All other subscales scores were lower following both HIIT and BRTH, though were not statistically significant different from pre-test values. No statistical between-intervention differences were detected. The preliminary results from this research provide evidence that acute use of HIIT exercise provides similar or better positive effects on PTSD symptoms as BRTH and that HIIT exercise can be used as a symptom management tool for PTSD.
Graduate

碩士
國立中正大學
運動競技系運動與休閒教育研究所
105
Purpose: The aim of this study is to investigate impact of training effect to different rest duration during interval training. And compare the difference of two self- selected rest durations to make suggestion for the runners who intents to do interval training. Method: 8 elite runners (6 male and 2 female, age 24.8±5.8, height 168.8±7.9cm, weight57.5±6.5kg, 5000M 16.9±2.0min) performed treadmill test to collect the VO2max, vVO2max and HRmax data as the reference of interval training intensity. All participants were assigned to 3 groups. Each group performed 4 sessions of 1200M x 5 rounds by vVO2max and 1 session of 800M x 8 slightly higher intensity than vVO2max of interval training on the track. The rest duration of each round was randomly assigned to each group by 1, 2 and 4 minutes in first 3 rounds of 1200Mx5. All participants performed the 4th session interval training by self-selected rest duration. The last session was 800Mx8 self-selected rest duration. Data was analyzed by One-way ANOVA, Repeated measure t test and Two-way ANOVA repeated measure to compare the maximum heart rate during running period, lowest heart rate during rest period, blood lactate at 3-5 minutes post exercise of each session and running time of each round of interval training in between different rest durations. The level of significance was set as .05. Result: The difference of 1200Mx5 running time, maximum heart rate during running period and blood lactate at 3-5 minutes post exercise of different rest duration 1 min, 2 min, 4 min and self-selected 1.94±0.68 min) were not significant. The lowest heart rate in 1 minute rest duration was significantly higher than other rest durations. The post exercise blood lactate of 800mx8 self-selected rest duration (1.69±0.26 min) was higher than 1200M×5 self-selected rest duration. Conclusion: According to running time, maximum heart rate during running period and blood lactate, the impact of 1-4 minutes rest duration would be same for1200 m×5 interval training. One minute rest duration for 1200Mx5 interval training would result in higher heart rate at rest duration.

In light of the current global prevalence of overweight and obesity, the associated health risks, and the continuing adoption of sedentary lifestyle, this thesis investigated some of the factors that contribute to exercise adherence, directly comparing high-intensity whole body interval training and continuous endurance training. 68 inactive university aged adults (Age: 21.4±3.4 yrs, BMI: 25.6±4.6 kg/m2, VO2peak 40.1±5.7 ml/kg/min) were randomized into one of three groups; a non-exercise control, whole body high intensity training, or continuous endurance training. Aerobic capacity measurements, time to completion trials, muscular endurance, and core strength measures were taken at pre, post and follow up testing sessions. Psychological questionnaires were also administered during exercise as well as throughout the study. Following the intervention both exercise groups demonstrated equivalent improvements in aerobic performance, with only the interval group experiencing improved muscular and core endurance. After the 2-month follow up testing sessions the interval group lost all aerobic and core adaptation, with endurance only experiencing a partial loss. This finding indicates that the interval group did not adhere to exercise at a level that was high enough to preserve the adaptations associated with training. This finding is further supported by the psychological factors measured throughout this study, including acute affect, enjoyment and intentions to engage in future exercise.
Thesis (Master, Kinesiology & Health Studies) -- Queen's University, 2013-10-31 15:08:15.524

碩士
臺北市立大學
運動健康科學系碩士班
102
Background：To dancers, they need better physical conditions and well cardiopulmonary ability to support them to do skillful dance movement. It costs good aerobic and anaerobic capacity, better muscle endurance, coordination, body stability and flexibility. We used suspension exercise system(TRX) on dancers and observed their exercise performance after high-intensive interval training. Purpose：We used high-intensive interval training program on dancers and observed the influences on physical fitness and sport-related fitness. Method：30 students in dance took 6 types of high-intensive interval training programs on TRX. Each movement took 30 seconds, and rest for 30 seconds between each movement. The training took twice a week for 8 weeks, and increased 10 seconds every week. We compared the performance before and after training. Results: The participants had significantly lower body fat percentage, higher cardiopulmonary index, and better performance in the 60-second sit-ups and standing long jump after 8 weeks of suspension exercise training (all p<0.05). In the sport-related fitness tests, the participants had significantly improved performance in the eyes-opened with insole balance test, T-test agility, explosive force of acceleration, explosive force of vertical jump, and anaerobic capacity (all p <0.05). There was no significant change in the VO2max and HRmax after the intervention. Conclusion: The dancers had significant improvements in their anaerobic capacity after 8 weeks of high-intensity interval suspension exercise training. The oxygen uptake efficiency slope increased after exercise training among our participants while their VO2max remained unchanged, which suggested that the oxygen uptake efficiency of our participants should have been improved after the intervention. Furthermore, our study demonstrated improved performance of balance, agility, and explosive force of lower extremity through the activation of core muscles and lower-limb muscles. Key words：dancers，high intensity interval training，suspension，maximal oxygen uptake

Aerobic fitness and repeated high-intensity efforts have been shown to be a determinant in the performance of team sports, especially in the ability to finish a match, to cover a distance, to repeat and recover between sprints and explosive movements (e.g. accelerations, changes of direction; COD) and to reduce the deterioration in some technical skill. Due to this, coaches must appropriately develop these capacities to adequately prepare athletes for match-play demands. High-intensity interval training is considered an effective and time efficient means to optimise individual physiological adaptation. However, the best processes which examine these qualities (physical testing protocols), prescribe training and monitor the response of this training requires attention, particularly in team sport athletes that possess heterogenous physical attributes. Therefore, this thesis aimed to examine a valid and reliable approach to assess the training outcome as well as prescribe and monitor the training process in rugby league athletes.