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Tomonari Takeshita, Hiroaki Noro, Keiichiro Hata, Taira Yoshida, Tetsuo Fukunaga, and Toshio Yanagiya

net work of the ankle joint was higher in the FFS than in the RFS at the same running speed. 14 Excessive mechanical work (ie, excessive muscular work) in the FFS would make the FFS less economical than the RFS. To better understand the relationship between the foot strike pattern and energy

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Shane R. Wurdeman, Jessie M. Huisinga, Mary Filipi, and Nicholas Stergiou

Patients with multiple sclerosis (MS) have less-coordinated movements of the center of mass resulting in greater mechanical work. The purpose of this study was to quantify the work performed on the body’s center of mass by patients with MS. It was hypothesized that patients with MS would perform greater negative work during initial double support and less positive work in terminal double support. Results revealed that patients with MS perform less negative work in single support and early terminal double support and less positive work in the terminal double support period. However, summed over the entire stance phase, patients with MS and healthy controls performed similar amounts of positive and negative work on the body’s center of mass. The altered work throughout different periods in the stance phase may be indicative of a failure to capitalize on passive elastic energy mechanisms and increased reliance upon more active work generation to sustain gait.

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Bernard Liew, Kevin Netto, and Susan Morris

approved by the Curtin University Human Ethics Committee (RD-41-14). The detailed experimental protocol and results on running joint mechanical work have been previously published. 21 Overground backpack carriage running was performed at 3 velocities (3.0 m·s −1 , 4.0 m·s −1 , 5.0 m·s −1 ), whilst

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Aurélien Patoz, Thomas Blokker, Nicola Pedrani, Romain Spicher, Fabio Borrani, and Davide Malatesta

. PubMed ID: 8471993 doi:10.1139/h93-005 8471993 10.1139/h93-005 24. Borrani F , Candau R , Perrey S , Millet GY , Millet GP , Rouillon J-D . Does the mechanical work in running change during the VO 2 slow component? Med Sci Sports Exerc . 2003 ; 35 ( 1 ): 50 – 57 . PubMed ID

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Nancy L. Keim, Amy Z. Belko, and Teresa F. Barbieri

Energy expenditure (EE) was measured at specific steady-state work rates to determine if body fat percentage or gender was associated with exercise EE, substrate oxidation, or work efficiency. Body fat percentage (leaner vs. fatter men, 9-15% vs. 20-25% fat; leaner vs. fatter women, 16-24% vs. 32-48% fat) was not related to work efficiency or submaximal EE. Fatness affected substrate oxidation in men but not in women. Compared to fatter men, leaner men had higher fat oxidation (6.7 ± 1.6 vs. 1.4 ± 2.0 mg · kg fat-free mass [FFM]1 · min1; p < .01) and lower carbohydrate oxidation (26.6 ± 4.2 vs. 39.3 ± 5.0 mg ⋅ kg FFM1min1; p< .01) at 60% V˙O2max. When men and women of similar fatness and relative aerobic capacity were compared, men had higher EE measured as kilojoules per minute but similar rates of EE and substrate oxidation per kilogram of FFM at 40-60% V˙O2max. It was concluded that body FFM, not fatness, is a determinant of exercise EE, whereas fatness is associated with differences in exercise substrate oxidation in men. Along with aerobic fitness, gender and fatness should be considered in future studies of exercise substrate oxidation.

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Loren Z.F. Chiu and George J. Salem

Potentiation has been reported in power tasks immediately following a strength stimulus; however, only whole-body performance has been assessed. To determine the acute effects of weightlifting on vertical jump joint kinetics, performance was assessed before, during, and after snatch pull exercise in male athletes. Jumping was assessed using 3D motion analysis and inverse dynamics. Jump height was enhanced at the midpoint (5.77%; p = .001) and end (5.90%; p < .001) of the exercise session, indicating a greater powergenerating ability. At the midpoint, knee extensor net joint work was increased (p = .05) and associated with increased jump height (r = .57; p = .02). Following exercise, ankle plantar flexor net joint work was increased (p = .02) and associated with increased jump height (r = .67; p = .006). Snatch pull exercise elicited acute enhancements in vertical jump performance. At the midpoint of the exercise session, greater work at the knee joint contributed to enhanced performance. At the end of the exercise session, greater work at the ankle contributed to enhanced performance. Consequently, potentiation is not elicited uniformly across joints during multijoint exercise.

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Michael J. Asmussen, Glen A. Lichtwark, and Jayishni N. Maharaj

energy in muscle and other tissues . Nature . 1977 ; 265 ( 5590 ): 114 – 117 . PubMed ID: 834252 doi:10.1038/265114a0 10.1038/265114a0 11. Cavagna G , Kaneko M . Mechanical work and efficiency in level walking and running . J Physiol . 1977 ; 268 ( 2 ): 467 – 481 . PubMed ID: 874922 doi:10

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Samuel E. Masters and John H. Challis

on the net negative mechanical work, net positive mechanical work, and total mechanical work produced at each joint. Results The change in volume ratio indicated by the deformation gradient tensors of the thigh and shank indicate large volume changes during stance compared with the swing phase

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Mhairi K. MacLean and Daniel P. Ferris

biomechanical perspective, an exoskeleton that assists at one lower limb joint but not others should alter energetic cost differently depending on the locomotor task. A large majority of the total mechanical work performed by muscles during a step can be calculated as the summation of positive and negative

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Mathieu Lacome, Ben M. Simpson, Yannick Cholley, Philippe Lambert, and Martin Buchheit

, using power law modeling, the peak locomotor intensity of different typical SSGs with those of official matches in terms of running demands and mechanical work (MechW) over different rolling average durations. A second objective of the present study was to examine the effect of playing positions on the