Phenotyping of human muscle based on its profile of myosin heavy chain isoforms is commonly used to help understand changes in muscle function. However, in many instances, measureable changes in force output or contractility occur in the absence of any change in myosin heavy chain profile. Therefore, more sophisticated analysis is required. Proteomic techniques including 2-dimensional gel electrophoresis, highperformance liquid chromatography and peptide mass spectrometry can be used to investigate changes in the abundance of hundreds of proteins simultaneously. To date, such techniques have not been used to specifically characterise the human myofibrillar proteome, or study how the myofibrillar proteome relates to muscle outputs such as peak isometric force or the velocity of contraction. This thesis presents a series of studies that develop proteomic techniques for the analysis of myofibrillar proteins as well as optimisation of techniques for measuring the range of muscle output fro.....

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Journal of Sports Science and Physical Education 5(2): 9-14, 2016 - Jump squat tests can be used to investigate the differences in the force - velocity (f-v) profile in movement that is more a sport-specific than isolated exercises such as open chain leg extension. However, squat jumps involve multi-joint movement, making it questionable which muscle is the main contributor for the movement. The main aim of this study is to develop a test of isolated knee extension that encompasses the entire range of human f-v relationship and to investigate the correlation between linear encoder and kinematic measurement of angular velocity using a camera system during unloaded kicking. One healthy male subject volunteered to participate in the study and performed 10 unloaded kicks (knee extension). A cuff was strapped around the lower leg, approximately 2 cm above the medial malleoli and connected to a linear velocity encoder (MuscleLab Ergotest version 4010, Norway). During the test sessions, three.....

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Substantial research compared between specializing and diversifying in a particular sport but few scrutinised across multiple sports. This study examined the developmental pathways taken by individual sport (IS) and team sport (TS) athletes from two Malaysian national sports schools. Student athletes (N=117) aged 16 and above completed the Participation History Questionnaire. Information pertaining to the participant’s main sport and other sports he/she was engaged in was obtained. In comparison with TS athletes,the IS athletes were found to have a significant later start for most of their sport-relatedmilestones (p < 0.05). However, the IS athletes (M = 14.3 y, SD = 1.7) started competing ininternational competitions significantly earlier than the TS athletes (M = 15.3 y, SD = 1.1; p = 0.004, d = -0.72) and only the IS athletes reported competing in the Commonwealth, World and Olympic championships. Interestingly, the IS athletes (M = 2.5 sports, SD = 1.3) participated in significan.....

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The maximum force output of skeletal muscle exhibits a circadian rhythm and is associated with time-of-day differences in athletic performance. We investigated whether the diurnal difference in force output is associated with changes to the post-translational state of muscle proteins using non-targeted proteomic techniques. Ten physically active men (mean ± SD; age 26.7 ± 3.7 y, height 1.77 ± 0.08 m, body mass 74.9 ± 9.8 kg) performed experimental sessions in the morning (0800 h) and evening (1700 h) that were counterbalanced in order of administration and separated by at least 72 h. Each session included measurements of maximal voluntary contraction (MVC; including twitch-interpolation) and peak rate of force development (RFD) of the knee extensors. Samples of vastus lateralis were collected immediately after exercise and were analysed by ‘top-down’ and ‘bottom-up’ proteomic methods. Muscle force in the evening (754.4 ± 112.9 N) was significantly (P..

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