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1
Stavric, Verna A. "Muscle power after stroke". AUT University, 2007. http://hdl.handle.net/10292/131.
Testo completoAbstract (sommario):
Stroke is the leading cause of disability worldwide. It often leads to mobility limitations resulting from deficits in muscle performance. While reduced muscle strength and rate of force production have been reported, little is known about the power generating capability of people after stroke and its relationship to mobility. Research in other populations has found that measures of muscle power may have a greater association with activity performance than do measures of muscle force alone. Consequently, in an attempt to optimise power, investigators have focused on identifying ideal parameters within which to train for power. One such parameter is the identification of the loading level at which maximal power is generated. Literature reporting optimal loads from both young athletic and healthy older populations has yielded mixed results, making the applicability to a hemiparetic population difficult. The purpose of this study was to investigate muscle power performance at differing loads and to determine at what load muscle power is best elicited in hemiparetic and age and gender matched control groups. A secondary aim was to ascertain whether there is a relationship between the muscle power values obtained and activities such as gait, stair climbing and standing from a chair. Twenty nine hemiparetic volunteers and twenty nine age and gender matched controls were evaluated. Involved and uninvolved legs of the stroke group and a comparison leg of the control group underwent testing. Leg press muscle power was measured using a modified supine leg press machine at 30%, 50% and 70% of a one-repetition maximum (1-RM) load. Participants were positioned on the leg press machine and asked to push, with a single leg, as hard and as fast as they could. Data was collected via a mounted force platform and a linear transducer connected to a platform on which the participants lay. From these, power was able to be calculated. The activities were timed while being performed as fast as possible. The results showed that peak muscle power values differed significantly between the involved, uninvolved and control legs. Peak leg power in all three leg groups was greatest when pushing against a load of 30% of 1-RM. Involved leg peak power tested at 30% of 1-RM (Mean:240; SD:145 W) was significantly lower (p<0.05) than the uninvolved leg (Mean:506; SD:243 W). Both the involved and uninvolved legs generated significantly lower peak power (p<0.05) than the control leg (Mean:757; SD:292 W). Correlations were found between the involved leg peak power and gait speed and involved leg peak power and stair climbing (r=0.6-0.7, p<0.05). No correlation was found between paretic leg peak power and chair stands. The control group leg peak power demonstrated significant associations with the performance of all three activities.In summary, there were significant differences between the involved and the uninvolved leg in power production after stroke. As well, there are significant differences between the uninvolved leg and the leg of those not affected by stroke. Power was related to a number of activities.
2
Hamby, Derek Grady. "Chronic effects of creatine monohydrate on strength and power". Virtual Press, 1998. http://liblink.bsu.edu/uhtbin/catkey/1074541.
Testo completoAbstract (sommario):
The use of creative monohydrate (CM) supplementation by athletes to increase strength and lean body mass has great anecdotal support. Therefore, the purpose of this investigation was to document the chronic effects of CM supplementation on resistance trained athletes. Sixteen collegiate football players were randomly separated into a CM and placebo (P) group. Supplementation in capsule form consisted of 5 g CM or P per day throughout a 10 week resistance training program. Pre- and Post-testing consisted of 1) Weight. 2) Body fat estimation. 3) One repetition maximal bench press, squat, and power clean. 4) Cybex testing was also included. Results revealed the CM group was able to significantly increase measures of strength and power, as well as increase body mass without a change in body fat %, while the P group showed no significant changes. Data was analyzed using a paired t-test and ANCOVA (p < 0.05). CM PPrePostPrePostBody Wt (lbs)234.5 + 34.41237.37 + 31.34*215.57 ± 55.12213.0 ± 48.897-site fat %15.37+5.5116.68+6.5813.52 + 10.0913.58+8.33Bench Press (lbs)328.75 + 27.87- 340.0 + 27.65*287.14 + 58.94283.57 + 48.71Squats (lbs)532.86 + 130.92592.14 + 123.86*489.17 + 149.81512.50 ± 161.89Power Cleans271.88 + 47.73288.75 + 45.34*246.00 + 33.99241.00 + 64.65* Denotes significant measureThe data from this study supports the anecdotal claims. Further, contrary to what would be expected with long term resistance training alone, the placebo group failed to increase strength and power measures. This suggests that the resistance program lacked sufficient stimuli or that overtraining might have occurred. However, subjects ingesting CM were able to increase strength and power measures. Thus, it appears that CM may also serve as a buffer to overtraining.School of Physical Education
3
Sonnekalb, Sara. "Impact of different warm-up conditions on hamstring torque and power". Connect to this title online, 2005. http://www.oregonpdf.org.
Testo completoAbstract (sommario):
Thesis (M. Ed.)--Bowling Green State University, 2005.Includes bibliographical references (leaves 38-44). Also available online (PDF file) by a subscription to the set or by purchasing the individual file.
4
Dolan, Patricia. "Maximal short-term power output from human muscle". Thesis, London Metropolitan University, 1985. http://repository.londonmet.ac.uk/3313/.
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5
Winsley, Richard James. "Peak aerobic power of children". Thesis, University of Exeter, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.388595.
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6
Bennie, Kirsty Jane. "Electromyographic assessment of human muscle function". Thesis, University of Bristol, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.322357.
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7
Gilliver, Sally Frances. "The determinants of power in isolated skinned muscle fibres". Thesis, Manchester Metropolitan University, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.523112.
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8
Gilmour, Kathleen Mary. "Power output and efficiency of asynchronous insect flight muscle". Thesis, University of Cambridge, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.240111.
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9
Baker, Julien Steven. "Optimisation considerations for the measurement of human muscle power". Thesis, University of South Wales, 2000. https://pure.southwales.ac.uk/en/studentthesis/optimisation-considerations-for-the-measurement-of-human-muscle-power(6dd8a26f-b3d9-47c4-8511-90bd35f18ac3).html.
Testo completoAbstract (sommario):
High intensity cycle ergometer exercise tests are designed to measure power outputs. Most of the tests utilise resistive forces that are based on total-body mass values (TBM). Conceptually, selecting an optimal resistive force based on total-body mass may not be the best approach. Resistive forces that reflect the mass of the lean tissue specifically involved in the performance of the diagnostic task may be more appropriate. To investigate this theory the following studies were proposed. STUDY ONE. To identify the upper body contribution to a cycle ergometer test via the handgrip. STUDY TWO. To examine any differences in power profiles, when loading procedures were based on total-body mass (TBM) or fat-free mass (FFM). STUDY THREE. To investigate the sympathoadrenergic and blood lactate responses, when loading procedures were based on total-bodymass (TBM) or fat-free mass (FFM).STUDY FOUR. To measure blood concentrations of, lipidhydroperoxides (LH), malondialdehyde (MDA), creatine kinase (CK)and myoglobin (Mb) that may occur when resistive forces were based on total-body mass (TBM) or fat-free mass (FFM). STUDY ONEIndices of mechanical power output were obtained from twelve subjects during high intensity leg cycle ergometry tests (20 second duration; 75 grams per kilogram total-body mass) using two protocols:one with a standard handle-bar grip (with - grip), and one with supinated wrists (without - grip). Peak mechanical power, mean mechanical power, fatigue index and total mechanical work values were calculated for each subject during each test, and the sample mean differences associated with the two protocols were compared using paired Student t-tests. The with-grip protocol yielded significantly greater peak mechanical power output and greater fatigue index than the without - grip protocol(886 ± 124 W vs 815 ± 151 W, respectively; and 35 ± 10% vs 25 ±8%, respectively ; P < 0.05}. The electrical activity of the anterior forearm musculature was measured in the twelfth subject during the performance of each of the test protocol in an initial attempt to quantify any differences in muscular activity between protocols. While peak mechanical power output was greater during the with - grip protocol,than during the without - grip protocol, the electromyographs showed much greater forearm muscle activity during the with - grip protocol. Thus the protocol which allowed for the greatest measure of peak leg power output was also associated with considerable arm muscle activity. These findings should be considered when blood samples are taken from the arm for the biochemical analysis of cycling tasks. STUDY TWOStudy two compared the maximal exercise performance of 10 men during friction braked cycle ergometry of 20 s duration when resistive forces reflected total-body mass (TBM) or fat-free mass (FFM). Fat mass was calculated from the sum of skinfold thicknesses. Increases(P < 0.05) in peak power output (PPO) were found between TBM and FFM (1015 ± 165 W TBM vs 1099 ± 172 W FFM). Decreases (P <0.05) were observed for the time taken to reach PPO (3.8 ± 1.4 s TBMvs 2.9 ± 1 s FFM). Pedal velocity increased (P < 0.05) during the FFM protocol (129.4 ± 8.2 rpm TBM vs 136.3 ± SrpmFFM). Rating of perceived exertion (RPE) was also (P < 0.05) greater for FFM (18.4 ± 1.6 TBM vs 19.8 ± 0.4 FFM). No changes were found for Mean Power Output (MPO), fatigue index (FI) or Work Done(WD) between trials. These findings suggest that high intensity resistive force loading protocols may need to be reconsidered. Results from this study indicate that the active tissue component of body composition needs consideration in resistive force selection when ascertaining maximal cycle ergometer power profiles. STUDY THREEThe purpose of study three was to compare the sympathoadrenergic and blood lactate responses to maximal exercise performance during 30s cycle ergometry when resistive forces were dependent on total-bodymass (TBM) and fat-free mass (FFM). Correlations (P < 0.05) were recorded between PPOs, and immediate post-exercise noradrenaline concentrations for both the TBM and FFM protocols. Increases (P < 0.05) in the concentrations of adrenaline, noradrenaline and lactate from rest to immediately post exercise were observed for both the TBM and FFM protocols, with decreases in concentration noted (P < 0.05) immediately post to 24 h post exercise (see table 6.3). There were no differences (P > 0.05) recorded between TBM and FFM during any of the blood sampling stages. These results are interesting when we consider that with increases in PPO recorded for the FFM protocol there were no differences between protocols in the estimation of neurophysiological and metabolic stress as determined by plasmaadrenaline, noradrenaline and blood lactate concentrations. STUDY FOUR. Study four compared power outputs, and blood levels of, lipidhydroperoxides (LH), malondialdehyde (MDA), creatine kinase (CK), myoglobin (Mb) and lactate ([La-]g) following 30 s of maximal cycleergometry exercise when resistive forces were dependent on total-bodymass (TBM) or fat-free mass (FFM). Alpha-tocopherol, Retinol and uric acid concentrations were also measured to quantify the activity of selected antioxidants. Cardiac troponin concentrations (cTnl) were also determined to exclude protein leakage from the myocardium. Increases in CK activity was recorded from rest to immediately post exercise during both the TBM and FFM protocols (P < 0.05 ; P < 0.05 respectively) and decreased from immediately post to 24 h post exercise during the FFM protocol only. LH increased from rest to immediately post exercise for both the TBM and FFM protocol (P < 0.05 ; P < 0.05 respectively) and decreased 24 h post exercise for both protocols. Differences in LH concentrations were also observed immediately post exercise between the TBM and FFM protocols (P < 0.05). Increases in MDA concentrations were recorded from rest to immediately post exercise for TBM (P < 0.05), with a decrease recorded from immediate post to 24 h post exercise. Differences in MDA concentrations were recorded between the TBM and FFM protocol immediately post exercise. Differences in TBM and FFM concentrations were also recorded immediately post exercise for Mb (P < 0.05). Blood lactate values([La~]B) increased (P < 0.05) from rest, to immediately post exercise,and returned to resting values 24 h post exercise for both the TBM and FFM. Alpha-tocopherol and uric acid concentrations decreased from rest to immediately post exercise for both TBM and FFM protocols (P < 0.05 ; P < 0.05 respectively) and increased 24 h post exercise. There were no changes observed in Retinol concentrations for any of the blood sampling stages. The results of the study suggest that greater power outputs are obtainable with significantly less muscle damage and oxidative stress when resistive forces reflect FFM mass during loading procedures. This finding may also be related to better force velocity relationships observed for the FFM protocol, ie more efficient mechanics of movement which may result in less strain, and therefore less internal damage. Findings from the study indicate that procedures that produce greater power values, with no difference in stress response, that are less damaging to muscle tissue and relate to the active tissue during this type of exercise, may need to be explored in preference to loading procedures that include both lean and fat masses.
10
Magoffin, Ryan Darin. "The Effect of Whole Body Vibration on Exercise-Induced Muscle Damage and Delayed-Onset Muscle Soreness". BYU ScholarsArchive, 2016. https://scholarsarchive.byu.edu/etd/6217.
Testo completoAbstract (sommario):
Current scientific evidence suggests that when whole body vibration (WBV) is used as a warm-up prior to performing eccentric exercise, delayed-onset muscle soreness (DOMS) is mitigated and strength loss recovers faster. These benefits were observed primarily in nonresistance-trained individuals. The aim of this study was to determine if WBV could mitigate soreness and expedite strength recovery for resistance-trained individuals when used as a warm-up prior to eccentric exercise. Thirty resistance-trained males completed 300 maximal eccentric contractions of the quadriceps after warming up with (WBV) or without (CON) WBV. Both CON and WBV experienced significant isometric (27.8% and 30.5%, respectively) and dynamic (52.2% and 47.1%, respectively) strength loss immediately postexercise. Isometric strength was significantly depressed after 24 hours in the CON group (9.36% p < 0.01), but not in the WBV group (5.8% p = 0.1). Isometric strength was significantly depressed after 48 hours in the CON group (7.18% p < 0.05), but not in the WBV group (4.02% p = 0.25). Dynamic strength was significantly decreased in both the CON and WBV groups both at 24 hours (19.1% p < 0.001, and 16.1% p < 0.001, respectively), 48 hours (18.5% p < 0.01, and 14.5% p < 0.03), and 1 week postexercise (9.3% p = 0.03, and 3.5%, respectively). Pain as measured by visual analog scale (VAS) was significant in both CON and WBV groups at 24 and 48 hours postexercise, but the WBV experienced significantly less soreness than the CON group after 24 hours (28 mm vs. 46 mm p < 0.01 respectively), and 48 hours (38 mm vs. 50 mm p < 0.01). Pain as measured by pain pressure threshold (PPT) increased significantly in both groups after 24 and 48 hours, but there was no difference in severity of perceived soreness. The use of WBV as a warm-up may mitigate DOMS but does not appear to expedite the recovery of strength in the days following eccentric exercise in resistance-trained individuals.
11
IJpma, Gijs. "Airway smooth muscle dynamics". AUT University, 2010. http://hdl.handle.net/10292/941.
Testo completoAbstract (sommario):
The current study aims to investigate the relative contributions of each of the processes that govern airway smooth muscle mechanical behaviour. Studies have shown that breathing dynamics have a substantial effect on airway constriction in healthy and diseased subjects, yet little is known about the dynamic response of the main instigator of airway constriction, Airway Smooth Muscle (ASM). In this work several models are developed to further the understanding of ASM dynamics, particularly the roles and interactions of the three dominant processes in the muscle: contractile dynamics, length adaptation and passive dynamics. Three individual models have been developed, each describing a distinct process or structure within the muscle. The first is a contractile model which describes the contractile process and the influence of external excitation on contractile behaviour. The second model incorporates the contractile model to describe length adaptation, which includes the reorganisation and polymerisation of contractile elements in response to length changes. The third model describes the passive behaviour of the muscle, which entails the mechanical behaviour of all non-contractile components and processes. As little data on the passive dynamics of the muscle was available in the literature, a number of experiments were conducted to investigate relaxed ASM dynamics. The experimental data and mathematical modelling showed that passive dynamics plays not only a dominant role in relaxed ASM, but contributes considerably to the dynamics of contracted muscle as well. A novel theory of sequential multiplication in passive ASM is proposed and implemented in a mathematical model. Experiments and literature validated the model simulations. Further integration of the models and improved force control modelling of length adaptation is proposed for future study. It is likely that the coupling of the models presented here with models describing other airway wall components will provide a more complete picture of airway dynamics, which will be invaluable for understanding respiratory disease.
12
Badhwar, Vinay. "Vis musculi, the use of muscle as a power source for implantable cardiac assist device design". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0029/MQ50715.pdf.
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13
Badhwar, Vinay. "Vis musculi : the use of muscle as a power source for implantable cardiac assist device design". Thesis, McGill University, 1998. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=21508.
Testo completoAbstract (sommario):
Transformed fatigue resistant skeletal muscle has been proposed as a potential power source for totally implantable ventricular assist systems (VAS). The goal of this study was to determine the optimal latissimus dorsi muscle (LDM) configuration capable of obtaining maximum power output. A device was designed to measure the power output and performance characteristics at varying levels of preload from each of four in situ configurations in Watts/kg of muscle(W/kg). Eight LDMs were acutely measured and revealed peak power output as follows: Sub-Dorsi (compliance chamber between LDM and chest wall): 8.3 +/- 1.6 W/kg; Circular (chamber in skeletal muscle ventricle): 16.4 +/- 6.2 W/kg; Linear-Origin (measurements from LDM thoracolumbar origin): 47.1 +/- 4.4 W/kg; Linear-Insertion (measurements from LDM humeral insertion): 59.9 +/- 12.1 W/kg, (ANOVA, p < 0.0001). A linear oriented LDM is capable of generating maximal power output comparable to current VAS requirements. Confirmation of these findings in mansformed, conformed, fatigue-resistant muscle will provide information essential for the optimal design of muscle powered ventricular assist systems.
14
Lewandowski, Beth Elaine. "An Implantable, Stimulated Muscle Powered Piezoelectric Generator". Cleveland, Ohio : Case Western Reserve University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=case1238702705.
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Paul, Serene Sulyn. "An Exploration of Muscle Power and Fall Risk in Parkinson's Disease". Thesis, The University of Sydney, 2013. http://hdl.handle.net/2123/9430.
Testo completoAbstract (sommario):
Impaired balance, impaired mobility and falls are common problems for people with Parkinson's disease. To guide interventions, there is a need to understand the association between impairments and balance and mobility tasks, identify potentially remediable fall risk factors and predict falls. To address these gaps, a simple clinical fall prediction tool was developed. Reduced muscle power and strength, freezing of gait and impaired cognition were found to influence balance and mobility, which along with these impairments are associated with fall risk. These studies provide strategies to address impairments, improve task performance and optimise fall prevention for people with Parkinson’s disease.
16
Koutsos, Ermis. "Real time sEMG based muscle fatigue monitoring using low power integrated circuits". Thesis, Imperial College London, 2016. http://hdl.handle.net/10044/1/57110.
Testo completoAbstract (sommario):
Electromyogram (EMG), the recording of the electrical impulses of the muscles, is a rich source of information, which can facilitate such an insight into our muscles and especially their activation and fatigue level. Muscle fatigue has been shown to be one of the most important biofeedback parameters of EMG in rehabilitation, ergonomics and training, by using measured results from the body to change the way we behave, improve our performance and achieve better compliance to rehabilitation. This thesis addresses the challenge of reliably and efficiently estimating a muscle’s fatigue state though monitoring surface EMG signals, with the use of low power integrated circuits. CMOS technology facilitates localised real-time processing to achieve complete miniaturisation, resulting in an information driven system rather that conventionally data driven system. Thus, reducing requirements on data transmission, saving power and increasing the degree of freedom for the user. Several EMG properties progressively change during muscle fatigue and can be quantified in the time and frequency domains using different processing techniques. CMOS technology allows to significantly reduce the power and size of the developed EMG processing technology. Firstly, a CMOS system is presented, capable of measuring the instantaneous Median Frequency (iMDF) of the EMG signal, which is considered the golden standard for muscle fatigue assessment. Continuing, a novel bit-stream cross-correlator design that greatly simplifies the sEMG signal without any loss of information is presented for the estimation of the EMG conduction velocity, which is associated with the physiological changes of the muscle during fatigue. Furthermore, a new metric similar to iMDF is introduced, combining the advantages of the bit-stream approach that can accurately track the spectral compression of the sEMG during fatigue with one bit representation. Lastly, a complete muscle fatigue monitoring System-on-Chip (SoC) is presented, offering complete insight into the underlying mechanisms and physiological changes during muscle fatigue through sEMG analysis while operating under both static and dynamic contractions. The proposed approach is scalable, as several muscle fatigue monitoring SoCs can operate in parallel and periodically relay key information about the muscle, thus reducing data transmission costs and bandwidth requirements. Finally, a succession of wearable EMG devices are presented, introducing the use of custom Application Specific Integrated Circuits in wearable electronics for unsupervised muscle fatigue monitoring. The wearable nodes are wireless while user ergonomics, power and weight were the primary design considerations.
17
Corn, Sarah D. "Effects of N-Acetylcysteine on fatigue, critical power, and muscle energy stores". Thesis, Manhattan, Kan. : Kansas State University, 2009. http://hdl.handle.net/2097/1632.
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Stone, Michael H. "Training Programs and Periodization to Optimize Gains in Muscle Strength and Power". Digital Commons @ East Tennessee State University, 2018. https://dc.etsu.edu/etsu-works/4583.
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19
Alsobrook, Nathan Gabriel. "The role of upper body power in classical cross-country skiing performance". Thesis, Montana State University, 2005. http://etd.lib.montana.edu/etd/2005/alsobrook/AlsobrookN0805.pdf.
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Herron, Todd J. "Molecular regulation of power output in single rat skinned cardiac myocytes". MU has:, 2002. http://wwwlib.umi.com/cr/mo/fullcit?p3052177.
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21
Bogdanis, Gregory C. "Recovery of power output and muscle metabolism following maximal sprint cycling in humans". Thesis, Loughborough University, 1994. https://dspace.lboro.ac.uk/2134/10437.
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22
袁永浩 e Wing-ho Stephen Yuen. "Surface electromyogram power spectra in the masseter and anterior temporal muscles in southern Chinese children and adults". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1989. http://hub.hku.hk/bib/B31232085.
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Yuen, Wing-ho Stephen. "Surface electromyogram power spectra in the masseter and anterior temporal muscles in southern Chinese children and adults /". Hong Kong : University of Hong Kong, 1989. http://sunzi.lib.hku.hk/hkuto/record.jsp?B12791908.
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Rose, Jacob A. "Hindlimb Morphology in Eastern Cottontail Rabbits (Sylvilagus floridanus): Correlation of Muscle Architecture and MHC Isoform Content with Ontogeny". Youngstown State University / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=ysu1403279058.
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Akers, Allen (Roy Allen). "Muscular Differences Between Female Power and Endurance Athletes". Thesis, University of North Texas, 1997. https://digital.library.unt.edu/ark:/67531/metadc277604/.
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Lau, Wai-shing Vincent, e 劉偉誠. "Comparison of power grip and lateral pinch strengths between the dominant and non-dominant hands for normal Chinese male subjects ofdifferent occupational demand". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2001. http://hub.hku.hk/bib/B31970138.
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Howlett, Richard A. "Human skeletal muscle carbohydrate metabolism during the onset of exercise at varying power outputs". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp03/NQ35798.pdf.
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Macaluso, Andrea. "Loss of muscle strength and power in older women and adaptation to resistance training". Thesis, University of Strathclyde, 2002. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=21208.
Testo completoAbstract (sommario):
The studies described in this thesis aimed to examine some of the mechanisms underlying the lower levels of muscle strength and power in older women, who are at higher risk than men for age-related disability, and some of the adaptations in response to resistance training. The initial study showed that it is not only a smaller contractile muscle volume, estimated separately from the intramuscular non-contractile tissue, which accounts for differences in quadriceps muscle strength, expressed as torque, between young and older women, but also a higher level of coactivation of the antagonist muscles. Lower limb explosive power, which depends on both strength and speed of movement, and is more predictive of functional difficulties than strength per se, was then compared between young and older women during a single leg-press action after optimisation of load. The older women could not even move the resistance at which the young women achieved maximum power. Their lower levels of power, which appear to be more affected by ageing than isometric strength, were due to lower levels of both force and velocity at which maximum power was measured. In the third study, the neural adaptations to a short-term resistance-training programme were investigated by analysing the time and frequency-domain characteristics of the surface electromyogram measuredo n the biceps-brachii muscle during constant-force sustained-isometric contractions. Older women responded to the same training programme with a lower increase in strength than the young women. This was accompanied by a different electromyographic response in the two groups. Finally, three modalities of resistance-training, which were carried out for 16 weeks on a cycle-ergometer at either high-resistance and low-speed, low-resistance and high-speed, or a combination of both, were shown to be equally effective in improving power, strength and selected functional abilities in a healthy population of 65-74 year-old women. The findings of these studies are discussed in relation to the current knowledge on mechanisms and adaptations of muscle strength and power in the older woman.
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Tallis, J. "Effects of physiological caffeine concentration on isolated skeletal muscle force, power and fatigue resistance". Thesis, Coventry University, 2013. http://curve.coventry.ac.uk/open/items/456841df-8168-4338-9877-61b3ec64de52/1.
Testo completoAbstract (sommario):
Caffeine is the most widely consumed socially acceptable drug in the world and is commonly used for its ergogenic properties with demonstrated performance enhancing effects in endurance, power and strength based activities. Despite a wealth of evidence concluding a caffeine induced performance benefit, the direct effects of the drug on peripheral physiological processes have not been fully examined. Early works showed high dose caffeine has direct force potentiating effect on skeletal muscle, a notion that has only recently been confirmed by James et al. (2005) to also occur at a maximal human physiological concentration (70µM). The present research, using mouse muscle as a model for mammalian muscle in general, provides an in-depth assessment of the direct effect of physiological concentrations of caffeine on isolated skeletal muscle performance. This research uniquely: quantifies the dose response relationship; assesses the effects of caffeine on maximal and sub maximal muscle power output and fatigue; looks at the relationship between muscles with different fiber type compositions. As high concentrations of caffeine and taurine are a constituent of many energy drinks, the suggested interaction of these ingredients to further potentiate muscle mechanical performance was also assessed. The study further examines how mammalian muscle mechanical properties change over an age range of development to aged, and how this differs between muscles with predominantly different anatomical locations and functions. In light of this the age related direct effect of physiological concentrations of caffeine was assessed in order to examine whether the ergogenic benefit changed with age. The present results demonstrate a direct muscle performance enhancing effect of physiological concentrations of caffeine that is likely to promote greater benefit on long duration endurance based activities. Furthermore, the present study demonstrates that there is no direct effect of physiological concentrations of taurine and no further performance enhancing benefit when combined with caffeine. Finally this research uniquely highlights the muscle specific age related changes in mechanical performance and further indicates that the direct effect of caffeine changes with age.
30
Schoeler, Gunnar. "The validation of muscle power output measures in lower and upper body resistance exercises". Master's thesis, University of Cape Town, 2009. http://hdl.handle.net/11427/2763.
Testo completoAbstract (sommario):
Includes abstract.Includes bibliographical references (p. 104-115).
The reliability and comparability of results obtained from different methods of assessment has been the source of debate for the last decade. Aim: To investigate the reliability and comparability of measurements of force, velocity and power measured simultaneously during upper and lower body resistance exercises for the following three methods: a) power derived from ground reaction force, i.e. using a force plate (FP), b) power derived from the displacement of the bar, i.e. displacement tracking laser (L) and c) power as a combination of force derived from ground reaction force (FP) and velocity derived from the displacement of the bar (L) (FPL). Methods: 15 Males with a history of resistance training of at least one year participated in the study.
31
Robinson, Leah E. "The Effects of Land versus Aquatic Plyometrics on Power, Torque, Velocity, and Muscle Soreness". The Ohio State University, 2002. http://rave.ohiolink.edu/etdc/view?acc_num=osu1029768218.
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Goodin, Jacob R., Caleb D. Bazyler, Satoshi Mizuguchi e Michael H. Stone. "Relationships between Muscle Architecture and Measures of Strength and Power in Collegiate Volleyball Players". Digital Commons @ East Tennessee State University, 2016. https://dc.etsu.edu/etsu-works/3835.
Testo completoAbstract (sommario):
PURPOSE: To examine the relationships between muscle architecture and countermovement jump height, peak power, and maximal strength in collegiate volleyball players. METHODS: Fifteen female volleyball players (20 ± 1.3y, 176.3 ± 6.6cm, 70.1 ± 8.4 kg) were recruited as part of an ongoing athlete monitoring program. Athletes were tested on measures of vastus lateralis (VL) and lateral gastrocnemius (LG) muscle thickness (MT), pennation angle (PA), and fascicle length (FL) using ultrasonography; countermovement jump height (CMJH, n = 14 and peak power allometrically scaled (CMJPPa, n = 14); and isometric peak force allometrically scaled (IPFa, n = 12). Pearson’s product moment zero-order correlations were used for analysis with critical alpha set to p ≤ 0.05. RESULTS: Analysis revealed a positive relationship between VL MT and IPFa (r = 0.64, p = 0.025) and an inverse relationship between LG MT and CMJH (r = -0.54, p = 0.048). There were positive relationships between VL PA and all performance measures and between LG PA and CMJPPa (r = 0.54 to 0.71, p. < 0.05), and inverse relationships between VL FL and CMJPPa and between LG FL and all performance measures (r = -0.59 to -0.67, p < 0.05). CONCLUSIONS: Better jumpers had larger PA and shorter FL in both VL and LG, and stronger athletes had greater MT in VL, showing that differences in muscle architecture can influence performance parameters. Considering these findings and the results from previous longitudinal studies demonstrating the effects of heavy strength training on muscle architecture, it is recommended that collegiate volleyball athletes incorporate heavy lower body strength training into their training plan in order to increase PA in VL and LG and MT in VL.
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Baker, Paul A. "ROLE OF SKELETAL MUSCLE MASS IN SEX-DEPENDENT POWER OUTPUT DURING FLYWHEEL RESISTANCE TRAINING". UKnowledge, 2018. https://uknowledge.uky.edu/khp_etds/54.
Testo completoAbstract (sommario):
Background: To determine the role of muscle mass in sex-dependent differences in power output during flywheel resistance training (FRT).
Methods: Twenty recreationally active (≥ 2 resistance exercise bouts per week), subjects (10 M, 10 F) completed 2 bouts of resistance exercise using a flywheel resistance training (FRT) device (Exxentric kbox 4 Pro) separated by at least one week. Each session consisted of 3 sets of 4 exercises (squat, bent-over row, Romanian deadlift, and biceps curl) with varying moments of inertia (0.050, 0.075, and 0.100 kg/m2, respectively) in random order. Each set consisted of 5 maximal effort repetitions with 3-minute recovery between sets. Average power, peak concentric and peak eccentric power were recorded and normalized to whole-body skeletal muscle mass (as calculated from bioelectrical impedence analysis). Additionally, linear regression analysis was used to determine the association between muscle mass and highest power output observed among all three inertial loads.
Results: Absolute average, peak concentric and peak eccentric power for all lifts was significantly higher for males compared to females except for peak eccentric power for biceps curl which showed no significant difference. After normalizing to skeletal muscle mass, power output remained significantly higher for men in Row average power and peak concentric power as well as average power for biceps curl. A significant main effect of inertial load was noted for both absolute and relative power output for all exercises except for squat average power and peak concentric power. Regression analysis revealed that power output increases linearly with skeletal muscle mass (R2 = 0.37-0.77).
Conclusions: Differences in power output between sexes during resistance exercise can largely be explained by differences in muscle mass. Indeed, muscle mass accounts for approximately 37-77% of the variance in power output during FRT depending on the exercise. Increasing inertial load tends to decrease power output during FRT.
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Martin, Andrew J. "Relationships among Muscle Fibre Typology, the Force-Velocity-Power relationship, and the Force-velocity profile during the Squat Jump and Sprinting". Thesis, Griffith University, 2020. http://hdl.handle.net/10072/398096.
Testo completoAbstract (sommario):
Background: Sport Science researchers have validated a novel methodology to determine the force-velocity profile (SFv) which can be optimized in the vertical profile to maximise an athlete’s power production. This profile represents an extension upon the well-known force-velocity-power relationship (FVPr) which is based on the 1938 Hill model. Early muscle physiology researchers identified that different skeletal muscle fiber typology (MFT) exist and have categorized these fiber types according to contractile characteristics, enzyme activities, morphological, and metabolic properties. The physiological characteristics between MFT display differences in maximum shortening velocity and time to fatigue, which results in contrasting force-velocity-power (FVP) production capabilities during exercise. Human MFT is thought to be largely determined genetically, with little influence from external stimulus (i.e., exercise training), leading to a predisposition for sporting success along a sporting domain spectrum, from sprint to endurance sports. Within elite sport, athletes are tested for jumping and sprinting performance to determine; the suitability of an athlete to a given sport, identify the needs of an athlete, the responses to training, and preparedness of athletes for elite competition. Much research has investigated the FVPr variables and the SFv during jumping and sprinting. To date however, research is yet to investigate important relationships among MFT, the FVPr, and the SFv during jumping and sprinting. As such, further experimental research is required to determine such relationships, and provide important implications for performance professionals and researchers alike.
Objectives: The primary objective of the research study was to to investigate apparent relationships between MFT and the mechanical variables of the SFv and the FVPr during the squat jump and sprinting. A secondary aim was to consider how those relationships may influence exercise performance.
Methodology: Nineteen developing rugby league (RL) athletes were assessed for MFT, as well as the mechanical variables derived from the force- velocity-power (FVP) profiles during the squat jump and sprinting. The FVPr and SFv mechanical variables were acquired by using the computational method for both jumping and sprinting. For jumping, the participants were required to complete a series of un-loaded and loaded barbell squat jumps, whereby the highest jump from each trial was used to determine the jumping FVPr and SFv. For sprinting, two trials of 30 m sprints were completed, whereby split times were recorded at 5 m intervals. The fastest trial from each participant was used to determine the sprinting FVPr, SFv, and mechanical application of force variables. Proton magnetic resonance spectroscopy (1H-MRS) was used to quantify carnosine concentration in the gastrocnemius muscle in order to estimate MFT. The carnosine concentration was compared to that of a control population of active, non-athlete males (n=40), whereby an individual carnosine Z-score was derived for the RL athletes. Carnosine Z-score MFT groups were formed using the known group difference technique, whereby all carnosine Z-scores above zero formed the positive carnosine MFT group (n=9), and below zero formed the negative carnosine MFT group (n=10). SPSS (v26) was used to perform t-tests and spearman’s correlations to determine significant differences and relationships between carnosine Z-score MFT groups and the mechanical variables, while Microsoft Office Excel (2016) was used to analyse group variables data (sample size, mean, and standard deviation) acquired by the t-tests, to calculate Cohen’s d effects size.
Results: MFT was not found to influence the SFv during jumping or sprinting, however, MFT was found to influence the FVPr, with differences for force, velocity, and power between MFT. Moderate associations were also found between carnosine Z-score and the mechanical variables (force-velocity-power). Maximal power output (PMAX) was significantly different between carnosine Z-score MFT groups during jumping (p= 0.041, d=1.01), and was moderately associated with MFT (r=0.598**). PMAX (W/kg) was thought to be most influenced by VO (m/s) (p=0.073, d=0.88) but not FO (N/kg) during the squat jump. FO (N/kg) was not significantly different between groups (p=0.920, d=0.05) and had a negligible association with MFT (r= -0.032). During sprinting the SFv was not significantly different between groups (p=0.224, d=0.58) and was not considered to be influenced by MFT (r= -0.053). PMAX (W/kg) during sprinting was found to have a significant difference between MFT groups (p=<0.001, d=2.12), and seemed to be most influenced by FO (N/kg) (r=0.858**). FO (N/kg) was also significantly different between groups (p=0.019, d=1.19), while VO was not (p=0.216, d=0.59), and VO had a low association to PMAX (r=0.030). PMAX was found to influence RFMAX with a very high correlation (r=0.993**) and RFMAX was found to be significantly different between MFT groups (p=0.001, d=1.97). Exercise performance was most associated with PMAX in both jump height (m) (r=0.801**) and 30-m sprint time (s) (r=-0.893**), and resulted in significant and highly significant differences between groups for the squat jump (p=0.038, d=1.03) and the 30-m sprint time (s) (p=<0.001, d=2.54).
Conclusion: Variation in MFT was not associated with variation in the SFv during the squat jump or sprinting, despite being associated with various mechanical variables derived from the FVPr. MFT was found to influence PMAX differently during the squat jump when compared to sprinting. This is thought to be due to the low velocity constraints of the Squat jump, compared to the high velocity motion of sprinting, which highlights the difference in force production capabilities at high velocities for type IIa/ IIx MFT (Aagaard & Andersen, 1998; Tihanyi, Apor, & Fekete, 1982). The magnitude of difference between PMAX (W/kg) in sprinting when compared to the squat jump supports this inference, and is thought (Aagaard & Andersen, 1998; Tihanyi et al., 1982) to have occurred due to the low velocity constraints during the squat jump. To confirm this finding, future studies investigating associations between MFT and the FVPr, should compare FVP mechanical variables between the squat jump and high velocity jumps, such as a counter movement jump or drop jump. Future research should also aim to determine PMAX (W/kg) thresholds as associated to carnosine Z-score to better advise practitioners in the field; during baseline testing, with exercise prescription, during athlete performance monitoring, and determining athlete suitability for elite sport. While this study has determined an association between MFT, the FVPr, and has demonstrated that MFT has likely influenced the associated exercise performance. It is possible other muscle morphology differences within these groups (pennation angle and cross-sectional area), may also contribute to performance differences found, and is a recommendation for future investigation.Thesis (Masters)
Master of Medical Research (MMedRes)
School of Medical Science
Griffith Health
Full Text
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Carbonnier, Anders, e Ninni Martinsson. "Examining muscle activation for Hang Clean and three different TRX Power Exercises : A validation study". Thesis, Högskolan i Halmstad, Biomekanik och biomedicin, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-17754.
Testo completoAbstract (sommario):
Background: Resistance training has proven to increase athletic performance, traditionally barbell training and Olympic Lifting have been used for this purpose. Sling training has recently been developed as a complement or substitution to traditional resistance training. Research has shown an increase in sport specific athletic performance and core stability with sling training. TRX Suspension Trainer is a newly developed sling training tool and to date no independent research has been done with the TRX. Purpose: To examine and compare muscle activation using TRX and the Olympic Lifting movement Hang Clean. Methods: 32 senior high school male soccer players participated in the study. Surface electromyographic (sEMG) data were collected on mm.erector spinae (back), m.gluteus maximus (glutes), m.vastus lateralis (quadriceps), m.semitendinosus (hamstrings) and m.gastrocnemius caput laterale (calf). Surface EMG data was collected when the subjects performed five different exercises, Hang Clean, TRX Squat Jump, TRX Front Squat and TRX Power Pull. In addition a Squat Jump was used as reference. Results: A similar muscle activation was found between Hang Clean (674 µV), TRX Squat Jump (684 µV) and TRX Front Squat (691 µV). TRX Power Pull showed the highest activation for mm.erector spinae and m.gluteus maximus but the lowest when comparing total muscle activation for all measured muscles. Conclusion: The similar amount of muscular activation for Hang Clean, TRX Squat Jump and TRX Front Squat indicates that the TRX Suspension Trainer can be used as a complement, for experienced athletes, or a substitution, for novice athletes, to traditional strength training. Coaches and athletic trainers should acknowledge the need and the importance of resistance training for athletic performance.
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Levin, Mindy F. "The influence of transcutaneous electrical nerve stimulation (tens) on hemiplegic spasticity and voluntary muscle power /". Thesis, McGill University, 1990. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=74642.
Testo completoAbstract (sommario):
These studies investigated possible relief of spasticity in hemiparetic subjects by transcutaneous electrical nerve stimulation (TENS) and its underlying mechanisms. The first two studies quantified the disorders in reflex and voluntary motor functions and addressed the reproducibility of their measurement and their correlation with spasticity scores. Soleus stretch reflexes were enhanced and isometric voluntary contraction force was decreased linearly with increasing spasticity. The last two studies addressed the effects of single and repetitive TENS stimulation on spasticity, reflex and isometric voluntary contractions. Compared to placebo stimulation, single 45 min sessions of TENS prolonged H and stretch reflex latencies for up to 60 min following stimulation. Repetitive (15 daily, 60 min) applications significantly decreased spasticity scores, Hvib/Hctl ratios, stretch reflexes and co-contraction while improving dorsiflexion force. The improvement in spasticity and voluntary motor control may partly have been mediated by presynaptic inhibition and reduced hyperactive stretch reflexes thereby 'unmasking' descending control.
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Talpey, Scott. "Efficacy of various complex and contrast set protocols acute responses and chronic muscle power development". Thesis, Federation University Australia, 2014. http://researchonline.federation.edu.au/vital/access/HandleResolver/1959.17/75689.
Testo completoAbstract (sommario):
PhD"The complex and contrast methods are two separate, but related approaches to resistance training that present intriguing options for coaches who are seeking to enhance an athletes explosive lower body movement. This intrigue is caused by the post-activation potentiation (PAP) phenomenon, which provides the physiological underpinning for these training methods. Exploitation of the PAP response is believed to elicit acute responses, and ultimately chronic adaptations in an individuals explosive force producing ability to an extent that is greater than can be obtained through conventional training methods. However, evidence to support the use of these training methods is derived from investigations that have reported acute increases in performance within a single session and not over an extended period of time. Additionally, the complex method of training, in which sets of a heavy resistance exercise (conditioning action) are performed prior to sets of a lighter explosive exercise has not been investigated as extensively as the contrast method, in which heavy and light exercises are alternated in a set-by-set fashion, leading to question which method is more effective. Furthermore, it is currently not understood if a static or dynamic conditioning action is more effective in complex or contrast methods, and how a change in body position from seated to standing acutely effects explosive lower body movement. Therefore, four studies were designed to address these current gaps in the literature." "The first study sought to determine the reliability of the explosive force variables of jump height (JH), peak bar velocity (BV), peak force (PF), and peak power (PP) obtained from a countermovement jump (CMJ) test." "The second study of the thesis examined the acute responses to five different unconventional resistance training methods which attempted to capitalise on a PAP response and one conventional session where CMJs were performed without any influence from a previous conditioning action." "The third investigation of this thesis was a nine-week training study in which participants were randomly assigned to two training interventions, conventional (n = 11) or complex (n = 9)." "Due to the dramatic improvements observed in CMJ height, that were not observed in other variables, it was questioned whether the specific instructions provided to participants during training and testing throughout the study to jump for maximal height had any influence on these results. This question led to the design of a fourth study. Though not directly related to complex or contrast training, this investigation into the effects of instructions on CMJ variables has scope to alter the way this test is conducted both in research and in a practical setting.
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Jacobson, Erik Andrew. "Effect of ski pole stiffness on upper body power output in cross-country skiers". Thesis, Montana State University, 2008. http://etd.lib.montana.edu/etd/2008/jacobson/JacobsonE0508.pdf.
Testo completoAbstract (sommario):
The purpose of this study was to determine whether increased pole stiffness corresponds with higher measures of upper body power in competitive cross-country skiers. Fifteen elite/college level cross-country ski racers (8 men, 7 women) tested UBP on a custom-built double-poling ergometer. Ski poles tested were two models of the same brand with different factory-specified stiffness ratings. Subjects underwent three 10 s UBP tests (W10, W) and one 60 s UBP test (W60, W) for each pole type. UBP measures were defined as the average power output over the length of each test. Video recordings of the 10 s and 60 s tests were analyzed with digital imaging software to determine the maximum bend angle for each pole type. Ergometer and kinematic measures were compared by ski poles tested (stiff vs. less stiff) using a multivariate RMANOVA (α=0.05).
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NEGRO, MASSIMO. "EFFECTS OF 12 WEEKS OF ESSENTIAL AMINO ACIDS (EAA)-BASED MULTI-INGREDIENT NUTRITIONAL SUPPLEMENTATION ON MUSCLE MASS, MUSCLE STRENGTH, MUSCLE POWER AND FATIGUE IN HEALTHY ELDERLY SUBJECTS: A RANDOMIZED CONTROLLED DOUBLE-BLIND STUDY". Doctoral thesis, Università degli studi di Pavia, 2019. http://hdl.handle.net/11571/1245866.
Testo completoAbstract (sommario):
Objective: to counteract muscle mass, muscle strength and power loss during aging, and to study age-related change of neuromuscular manifestation of fatigue in relation to nutritional supplementation. Design: randomized controlled double-blind study. Setting: twice-daily consumption for 12 weeks of an Essential Amino Acids (EAA)-based multi-ingredient nutritional supplement containing EAA, creatine, vitamin D and Muscle Restore Complex®. Participants: 38 healthy elderly subjects (8 male, 30 female; age: 68.91±4.60 years; body weight: 69.40±15.58 kg; height: 1.60±0.09 m) were randomized and allocated in supplement (SUPP) or placebo (PLA) group. Mean Measurements: vitamin D blood level; Appendicular Lean Mass (ALM); Visceral Adipose Tissue (VAT); Maximal Voluntary Contraction (MVC) and Peak Power (PP); myoelectric descriptors of fatigue: Fractal Dimension and Conduction Velocity initial values (FD iv, CV iv), their rates of change (FD slopes, CV slopes) and the Time to perform the Task (TtT). Mean Results: significant changes were found in SUPP compared to baseline: vitamin D (+8.73 ng/ml; p<0.001); ALM (+0.34 kg; p<0.001); VAT (-76.25 g; p<0.001); MVC (+0.52 kg; p<0.001); PP (+4.82 W; p<0.001). Between group analysis (SUPP Vs. PLA) showed improvements: vitamin D blood levels (+11,72 ng/ml; p<0.001); Legs FFM (+443.7 g; p<0.05); ALM (+0.53 kg; p<0.05); MVC (+1.38 kg; p<0.05); PP (+9.87 W; p<0.05). No statistical changes were found for FD iv, CV iv, FD and CV slopes and TtT, either compared to baseline or between groups. Significant correlations between mean differences in SUPP group were also found. Conclusion: the study demonstrates that in healthy elderly subjects an EAA-based multi-ingredient nutritional supplementation of 12 weeks is not effective to change myoelectric manifestation of fatigue and TtT failure but can positively affect muscle mass, muscle strength, muscle power and VAT, counterbalancing more than one year of age-related loss of muscle mass and strength.
Keywords: essential amino acids, creatine, vitamin D, antioxidants, muscle aging, muscle strength, muscle power, muscle fatigue.Objective: to counteract muscle mass, muscle strength and power loss during aging, and to study age-related change of neuromuscular manifestation of fatigue in relation to nutritional supplementation. Design: randomized controlled double-blind study. Setting: twice-daily consumption for 12 weeks of an Essential Amino Acids (EAA)-based multi-ingredient nutritional supplement containing EAA, creatine, vitamin D and Muscle Restore Complex®. Participants: 38 healthy elderly subjects (8 male, 30 female; age: 68.91±4.60 years; body weight: 69.40±15.58 kg; height: 1.60±0.09 m) were randomized and allocated in supplement (SUPP) or placebo (PLA) group. Mean Measurements: vitamin D blood level; Appendicular Lean Mass (ALM); Visceral Adipose Tissue (VAT); Maximal Voluntary Contraction (MVC) and Peak Power (PP); myoelectric descriptors of fatigue: Fractal Dimension and Conduction Velocity initial values (FD iv, CV iv), their rates of change (FD slopes, CV slopes) and the Time to perform the Task (TtT). Mean Results: significant changes were found in SUPP compared to baseline: vitamin D (+8.73 ng/ml; p<0.001); ALM (+0.34 kg; p<0.001); VAT (-76.25 g; p<0.001); MVC (+0.52 kg; p<0.001); PP (+4.82 W; p<0.001). Between group analysis (SUPP Vs. PLA) showed improvements: vitamin D blood levels (+11,72 ng/ml; p<0.001); Legs FFM (+443.7 g; p<0.05); ALM (+0.53 kg; p<0.05); MVC (+1.38 kg; p<0.05); PP (+9.87 W; p<0.05). No statistical changes were found for FD iv, CV iv, FD and CV slopes and TtT, either compared to baseline or between groups. Significant correlations between mean differences in SUPP group were also found. Conclusion: the study demonstrates that in healthy elderly subjects an EAA-based multi-ingredient nutritional supplementation of 12 weeks is not effective to change myoelectric manifestation of fatigue and TtT failure but can positively affect muscle mass, muscle strength, muscle power and VAT, counterbalancing more than one year of age-related loss of muscle mass and strength. Keywords: essential amino acids, creatine, vitamin D, antioxidants, muscle aging, muscle strength, muscle power, muscle fatigue.
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Trecroci, A. "POWER AND ENDURANCE CYCLING PERFORMANCE: THE KINESIO-TAPING APPLICATION AND THE INFRARED THERMOGRAPHIC ASSESSMENT OF MUSCULAR EFFORT". Doctoral thesis, Università degli Studi di Milano, 2016. http://hdl.handle.net/2434/366180.
Testo completoAbstract (sommario):
The present thesis has been written incorporating two different research lines involving the use of kinesio taping (KT) and the infrared thermography technology (IRT) in the field of physical exercise and performance analysis. Both topics are related to the involvement of cycling pattern in a laboratory environment assessing the role of skin behavior in terms of promotion (indirect) of muscle contraction and thermoregulation b KT and IRT, respectively.
The aim of this study was to determine whether the use of kinesio taping (KT) was helpful in increasing maximal-intensity cycling exercise. Sixteen active healthy subjects were enrolled in a randomized placebo, repeated measures design. All subjects were tested on a cycle ergometer under three conditions: without taping, taping along anterior thigh muscles, and sham taping across the same muscle groups. Results showed a significant increase in peak power output and total work after the longitudinally application compared to the condition with no tape applied (p<0.05). No significant difference was found between the two modes of application. Our findings indicated that the tactile stimulation of KT applied longitudinally provided positive effects during a sprint cycling performance in healthy and active subject.
The aim of the second study was to assess skin temperature and pedaling imbalance in response to maximal incremental exercise in elite cyclists. Ten competitive elite cyclists underwent a cycling incremental test to exhaustion. Kinetic variables, such as peak crank torque and asymmetric index (AI) were taken into account for propulsion and recovery phases at the beginning and at the end of the test. Thermal images of the thighs’ frontal surfaces (captured by infrared thermography, IRT) were recorded before, immediately after and 3 and 6 min after the end of exercise. Cyclists showed a certain degree of symmetry in skin temperature presenting a significant reduction at the exhaustion point for both lower limb. As regard bilateral peak crank torques, a significant interaction was found in the propulsive phase across the time, even though the AI was < 10%. However, in the recovery phase, a remarkable value of AI > 10% was reported. Elite competitive cyclists showed bilateral asymmetry between propulsive peak crank torques in a state of extreme fatigue (i.e. at the exhaustion) with a low value of AI. On the other hand, skin temperature dynamics, measured by IRT, presented a certain degree of symmetry in both right and left limb in response to maximal incremental test. Future studies are need to determine the effective usefulness of IRT to monitor bilateral force asymmetry.
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Mayer, Kirby. "CHANGES IN MUSCLE SIZE, QUALITY AND POWER ARE RELATED TO PHYSICAL FUNCTION IN PATIENTS WITH CRITICAL ILLNESS". UKnowledge, 2019. https://uknowledge.uky.edu/rehabsci_etds/56.
Testo completoAbstract (sommario):
Patients admitted to intensive care unit (ICU) are known to develop significant impairments in physical function. Patients with critical illness suffer up to 30% reductions in muscle size within the first ten days of admission to the ICU. Muscle strength testing, Medical Research Council-sum score, is current gold-standard to diagnosis ICU-acquired weakness and predicts risk of mortality and long-term physical function. Muscle power different from muscle strength in that it accounts for velocity of movement, is potentially a better independent predictor of function that has not been studied in this population. In addition, we hypothesize that muscle size and quality measured through ultrasound imaging has better applicability and prediction that strength testing. Therefore, we prospectively collected data surrounding these muscle parameters in patients admitted to the medicine ICU at University of Kentucky. Primary outcomes included physical function, muscle power with a novel assessment tool for the critically ill population, muscle strength, and muscle size and quality assess through ultrasound imaging. 36 patients admitted to ICU and 18 aged-matched controlled were enrolled. Patients had significantly lower scores on muscle power assessment at ICU discharge (33.6 ±19.0 W; t= 4.01, p < 0.001) and at hospital discharge (40.9 ±16.5 W; t= 4.81, p < 0.001) in comparison to controls (59.3± 14.7 W). Patients with better scores on muscle power assessment had significantly better scores on physical function measures (Six-minute walk test; rs = 0.548, p = 0.0001). Muscle size (cross-sectional area of rectus femoris muscle) and muscle power were strongly correlated (rs = 0.66, p < 0.0001). These data suggest that patients with critical illness have significantly reduced muscle power which directly related to deficits in physical function.
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Valdez, Dennis. "Bilateral asymmetries in flexibility, stability, power, strength, and muscle endurance associated with preferred and nonpreferred leg". [Gainesville, Fla.]: University of Florida, 2003. http://purl.fcla.edu/fcla/etd/UFE0000812.
Testo completo
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Ward, Ryan C. "Contribution of high school sport participation to young adult bone strength". Thesis, University of Iowa, 2018. https://ir.uiowa.edu/etd/6333.
Testo completoAbstract (sommario):
Nearly 8 million American adolescents participate in sports. Many sports (e.g. basketball, volleyball) require powerful muscle movements. Normally, participation declines in young adulthood. The purpose of this study was to assess longitudinal effects of interscholastic high school sport participation and muscle power on young adult bone strength. 295 young adults from the Iowa Bone Development Study participated in this study. Participants were classified into sport participation groups based on an interscholastic sport participation history questionnaire. Groups included Power Sport Participant (PSP), Other Sport Participant (OSP), and Nonparticipant (NP). Current physical activity (PA) behaviors were assessed via questionnaire. Dual x-ray absorptiometry (DXA) assessed hip areal bone mineral density (aBMD) and was used with hip structure analysis (HSA) to estimate femoral neck section modulus (FN Z) and hip cross-sectional area (CSA). Peripheral quantitative computed tomography (pQCT) provided stress-strain index (SSI) and bone strength index (BSI) at 38% and 4% cross-sectional tibial sites respectively. Vertical jump estimated muscle power at age 19. Gender-specific multiple linear regression predicted young adult bone outcomes based on sport participation groups. Mediation analysis analyzed effects of muscle power on relationships between sport participation and bone outcomes. All analyses were adjusted for current PA. For both males and females, bone outcomes for PSPs were greater than bone outcomes for NPs (P < 0.025). Bone outcomes for PSPs were also greater than OSPs in females (P < 0.025). Mean differences for PSPs and NPs differed between 6.5% to 15.7%. 14.2% to 27.5% of the effect of sport participation on bone outcomes was mediated by muscle power. These results provide evidence to say that former male power sport participants and other sport participants and female power sport participants have stronger bones than peers even when adjusting for current PA. Muscle power did not fully explain differences in all bone outcomes suggesting that sport participation has additional bone health benefits.
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Teichler, Liza S. Row Brandi. "The relationship between bat velocity, upper and lower extremity power and the rotational kinetic chain in NCAA Division II softball players /". Online version, 2010. http://content.wwu.edu/cdm4/item_viewer.php?CISOROOT=/theses&CISOPTR=362&CISOBOX=1&REC=18.
Testo completo
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Lundberg, Tommy. "The Effects of Aerobic Exercise on Human Skeletal Muscle Adaptations to Resistance Exercise". Doctoral thesis, Mittuniversitetet, Avdelningen för hälsovetenskap, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:miun:diva-21917.
Testo completoAbstract (sommario):
Aerobic exercise (AE) may interfere with muscle adaptations induced by resistance exercise (RE). Three experimental campaigns were conducted to explore the influence of AE on molecular, functional and muscular adaptations to acute and chronic RE. Twenty-nine men performed unilateral knee extensor RE preceded by AE (AE+RE). The contralateral leg did RE only. First, the influence of acute AE on muscle molecular responses to RE performed 6 h later was studied. Subsequently, this exercise regimen was implemented over 5 weeks training. The relationships between acute and chronic outcomes were examined and molecular responses to acute exercise were assessed in untrained and trained muscle. Finally, acute and chronic responses to AE+RE, interspersed by only 15 min recovery, were investigated.Phosphorylation of mTOR and p70S6K was greater after AE+RE than after RE. In parallel, myostatin was suppressed for a longer time after AE+RE. These results suggest that AE+RE enhance skeletal muscle anabolic environment more than RE alone (Paper I). After 5 weeks training, improvements in muscle strength and power were similar across legs. However, AE+RE prompted a greater increase in muscle size than RE, suggesting that AE potentiates the hypertrophic stimulus to RE training without altering muscle function progress (Paper II). Consistent with changes in whole-muscle size, AE+RE showed greater anabolic molecular responses than RE. As chronic training blunted this effect, it appears that AE offers a synergistic hypertrophic stimulus to RE only during short-term training (Paper III). Although putative regulators of hypertrophy such as p70S6K, myostatin and PGC-1a4 were examined, no molecular marker correlated with changes in muscle size, strength or power induced by training. Hence, this study challenges the concept that single molecular markers are viable predictors of training-induced muscle adaptations (Paper III–IV). When recovery time between exercise bouts was reduced to 15 min, AE+RE still produced a more substantial increase in muscle size than RE. However, progression of concentric strength was blunted. Thus, while restored muscle function between exercise bouts is a prerequisite for achieving maximal gains in strength and power, incomplete recovery appears not to compromise muscle hypertrophy (Paper V).Collectively, the results suggest that outcomes of AE+RE are impacted by chronic training and time allowed for recovery between exercise modes. Yet, the current study offers no support to the view that AE interferes with muscle hypertrophy induced by RE.
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Moraes, Kelly Cristina de Mello. "Efeitos do treinamento de força sobre variáveis neuromusculares e composição corporal de crianças e adolescentes". reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2017. http://hdl.handle.net/10183/172085.
Testo completoAbstract (sommario):
Este trabalho apresenta como objetivo verificar os efeitos de um programa de 12 semanas de treinamento de força sobre variáveis neuromusculares e composição corporal de crianças e adolescentes. A amostra foi composta por alunos de ambos os sexos, entre 10 a 14 anos de idade, que foram divididos em grupo experimental (GE; n=14) e grupo controle (GC; n=11). Para a classificação maturacional, avaliou-se o pico de velocidade de crescimento e a Escala de Tanner. Foram realizadas as seguintes avaliações: ultrassonografia para analisar a espessura muscular e a eco intensidade; força máxima através do teste de uma repetição máxima (1-RM) de extensores de joelho; pico de torque (PT) isométrico e taxa de produção de torque (TPT), no dinamômetro isocinético; ativação muscular por meio do sinal eletromiográfico (EMG) do Vasto Lateral (VL) e Reto Femoral (RF); potência de membros inferiores, através de saltos com contramovimento (CMJ) em tapete de contato; composição corporal e densidade mineral óssea (DMO) por absorciometria de dupla energia de raios-x (DEXA). Para analisar a normalidade e a homogeneidade dos dados das variáveis dependentes, foram realizados o teste de Shapiro-Wilk e o Teste de Levene, respectivamente. Foi utilizado o teste T independente para comparar as variáveis dependentes no momento basal entre grupos Após, aplicou-se o teste de correlação de Pearson, seguido pelo teste de regressão linear com o método backward, entre as variáveis de caracterização da amostra e as variáveis dependentes, sendo que as variáveis significativas (p<0,05) foram utilizadas como covariantes. Para verificar o efeito do treinamento de força, foi aplicada a análise de variância (ANOVA) de duas vias entre os grupos. O índice de significância adotado foi de 0,05 em todas as comparações. Após 12 semanas de TF, o grupo experimental melhorou a qualidade muscular, espessura muscular do Reto Femoral, 1-RM e TPT 0-100 ms, quando comparado ao grupo controle (p<0,05). A partir disso, pode-se constatar que o treinamento de força induz melhorias no sistema neuromuscular de crianças e adolescentes, melhorando parâmetros de saúde física.The gold from this study is to verify the effects of a twelve-week strength training program in neuromuscular variables, as well as the body composition from children and teenagers. The sample was comprised by the students of both sexes and divided into: experimental group (EG; n=14) and control group (CG; n=11). For the mature classification, it was evaluated the growth velocity peak (GVP) and the Tunner's stages. The following evaluations were done: ultrasonography to analyze the muscle thickness and echo intensity; maximum strength through the one repetition test (1RM) for the right knee extensors’; isometric peak torque (IPT) and rate of force development (RFD) at the isokinetic dynamometer; muscle activation by eletromiographic signal from the Vastus Laterallis (VL) and Recto Femoris (RF); lower limbs’ power through countermovement jumps (CMJ) at the contact rough; body composition and mineral bone density (MBD) by dual x-ray absormetry (DXA). The normality and homogeneity of the dependent variables were verified from the Shapiro-Wilk and Levene's tests, respectively It was made an independent t test in order to compare the differences between groups for the dependent variables at the basal moment. After, a Pearson correlation test was calculated, followed by a linear regression using the backward method, in order to compare the characterization variables from the sample and the dependent variables, using the ones with significance value (p<0,05) as a covariant. To verify the effect of the strength training, a two way analyzes of variance (ANOVA two way) was made between the groups. The 0,05 level of significance was adopted in all analyzes. After twelve weeks of strength training, the experimental group improved its’ muscle quality, Recto Femoris muscle thickness, 1-RM and RFD 0-100ms, when compared to the control group (p<0,05). From this, it could be stated that strength training induced improvements in the neuromuscular system of children and teenagers, improving physical health parameters.
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Secomb, Josh. "Training adaptations in lower-body muscle structure and physical performance capacities of competitive surfing athletes". Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 2016. https://ro.ecu.edu.au/theses/1914.
Testo completoAbstract (sommario):
The overall aim of this thesis was to increase strength and conditioning coaches, and sport scientists’ understanding of the lower-body muscle structures related to enhanced lower-body physical capacities, and how to best evoke desirable training-specific adaptations. To address this aim, three successive steps of research were evaluated: (1) analysis of the factors related to increased performance in competitive surfing, (2) relationships between lower-body muscle structures and factors associated with enhanced physical performance, and (3) comparison of the training-specific adaptations evoked from various training methods. Whilst this research specifically focused on competitive surfing athletes, these results may benefit the training practices of athletes from a wide range of sports. The comprehensive conclusion of the research studies in this thesis suggest that competitive surfing is highly reliant on lower-body force producing capabilities, with specific vastus lateralis and lateral gastrocnemius muscle structures significantly related to these lower-body physical performance capacities. Additionally, the separation of strength and, gymnastics and plyometric training may not be best practice for adolescent athletes. However, a short duration combined strength, plyometric and gymnastics training intervention appears to provide a significant stimulus to evoke desirable adaptations in lower-body muscle structure and physical performance capacities for athletes that have limited opportunities for training between major competitions. Therefore, this thesis has provided descriptive, predictive and determinant findings associated with the physical preparation of surfing athletes, and iii therefore, provides strength and conditioning coaches, and sport scientists with an enhanced understanding of how best to evoke desirable adaptations in lower-body muscle structure and physical performance capacities.
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Schurer, Geertruida Wilhelmina. "Changes in body composition, anaerobic muscle power, and pulmonary function with age in children with cystic fibrosis". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp04/mq24505.pdf.
Testo completo
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Blevins, Shayne Philip. "Improving the identification of osteopenia the relationship between muscle power, body mass index and bone mass density /". Online access for everyone, 2008. http://www.dissertations.wsu.edu/Thesis/Summer2008/S_Blevins_063008.pdf.
Testo completo
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Mayhew, Thomas Philip. "THE EFFECTS OF CONCENTRIC AND ECCENTRIC CONTRACTIONS PERFORMED AT EQUAL POWER LEVELS ON SKELETAL MUSCLE FIBER HYPERTROPHY". VCU Scholars Compass, 1991. https://scholarscompass.vcu.edu/etd/5228.
Testo completoAbstract (sommario):
There are no data available as to whether training with eccentric contractions are more effective than concentric contractions for producing skeletal muscle fiber hypertrophy. To better understand the effects of training with different contraction types two related studies were performed.
In the first study a device which is frequently used by clinicians for concentric and eccentric exercise, the Kin-ComR, was tested for accuracy and reliability. The measurements obtained from the force, angle, and speed transducers of this device were found to be accurate and reliable between days.
The purpose of the second study was to determine if there was a difference in the percent change of fiber area in the vastus lateralis muscle as a result of concentric and eccentric exercise at equal power levels. Twenty normal subjects were randomly assigned to two groups. Both groups exercised three times per week for four weeks on the Kin-Com dynamometer. One group performed concentric contractions of their right quadriceps femoris muscle at an intensity of 90% of their maximal concentric power through a range of 75° of knee extension. The other group performed eccentric contractions at the same relative power level. Needle muscle biopsies were obtained from the vastus lateralis muscle before and after the exercise program. Muscle fiber type differentiation was performed using a myosin adenosine triphosphatase stain at an alkaline preincubation. The percent change in fiber area was determined for each fiber type for each subject and a one-way ANOVA was used to analyze the data. Our results showed that the type II fibers of the concentric group exhibited a greater percent increase in area as compared to the eccentric group. The percent change in isometric torque was determined for each subject and a one-way ANOVA was performed on the data. The results showed that the concentric group increased maximal isometric torque production more than the eccentric group. Our results indicate that when exercising at the same relative power level a subject performing concentric contractions will 1) show greater muscle hypertrophy and, 2) improve in isometric torque production more than a subject training with eccentric contractions.