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H. Galbraith, J. Scurr, C. Hencken, L. Wood and P. Graham-Smith

This study compared the conventional track and a new one-handed track start in elite age group swimmers to determine if the new technique had biomechanical implications on dive performance. Five male and seven female GB national qualifiers participated (mean ± SD: age 16.7 ± 1.9 years, stretched stature 1.76 ± 0.8 m, body mass 67.4 ± 7.9 kg) and were assigned to a control group (n = 6) or an intervention group (n = 6) that learned the new one-handed dive technique. All swimmers underwent a 4-week intervention comprising 12 ± 3 thirty-minute training sessions. Video cameras synchronized with an audible signal and timing suite captured temporal and kinematic data. A portable force plate and load cell handrail mounted to a swim starting block collected force data over 3 trials of each technique. A MANCOVA identified Block Time (BT), Flight Time (FT), Peak Horizontal Force of the lower limbs (PHF) and Horizontal Velocity at Take-off (Vx) as covariates. During the 10-m swim trial, significant differences were found in Time to 10 m (TT10m), Total Time (TT), Peak Vertical Force (PVF), Flight Distance (FD), and Horizontal Velocity at Take-off (Vx) (p < .05). Results indicated that the conventional track start method was faster over 10 m, and therefore may be seen as a superior start after a short intervention. During training, swimmers and coaches should focus on the most statistically significant dive performance variables: peak horizontal force and velocity at take-off, block and flight time.

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Glenn Street, Scott McMillan, Wayne Board, Mike Rasmussen and J. Michael Heneghan

A comprehensive error analysis was performed on the impulse method. To evaluate the potential errors, jump height was recalculated after altering one of the measurement or calculation techniquaes while leaving the others unchanged, and then comparing it to the reference jump height (best estimate of true jump height). Measurement techniques introduced the greatest error. Low-pass filters with cutoff frequencies < 580 Hz led to systematic underestimations of jump height, ≤26%. Low sampling frequencies (<1,080 Hz) caused jump height to be underestimated by ≤4.4%. Computational methods introduced less error. Selecting takeoff too early by using an elevated threshold caused jump height to be overestimated by ≤1.5%. Other potential sources of computational error: (a) duration of body weight averaging period; (b) method of integration; (c) gravity constant; (d) start of integration; (e) duration of offset averaging period; and (f) sample duration, introduced < 1% error to the calculated jump height. Employing the recommended guidelines presented in this study reduces total error to ≤ ±0.76%. Failing to follow the guidelines can lead to average errors as large as 26%.

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Mark G.L. Sayers and Stephen Bishop

– 12 Typically, these researchers assess maximal and/or average power output either directly, measuring force-based variables (eg, using a force platform), or calculating these data from measures of bar displacement. However, the gross quantification of power used throughout this research has the

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Fawaz A. Alwadani, Huaqing Liang and Alexander S. Aruin

subject was asked to stand with his or her eyes open, barefoot, with his or her feet shoulder width apart on top of a force platform (model OR-5; Advanced Mechanical Technology, Inc., Watertown, MA) (natural stance) and over a rigid wedge placed on top of the force platform, which induced either

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Toshimasa Yanai, Akifumi Matsuo, Akira Maeda, Hiroki Nakamoto, Mirai Mizutani, Hiroaki Kanehisa and Tetsuo Fukunaga

the mound could satisfy the official baseball rules. Each tray was mounted on an aluminum baseplate having 4 T-shaped arms, which, in turn, was firmly fixed to the force platform FP1-3 (Figure  1 ). With this arrangement, the oversized trays were securely supported on the force platforms without

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Lewis J. Vizard, Gareth Peden and Maximilian M. Wdowski

, Hamburg, Germany) was used to measure both leg lengths from the anterior superior iliac spine to the lateral malleolus. A 12-camera 3D motion analysis system (Vantage 5; Vicon, Oxford, UK) synchronized with four 40- × 60-cm force platforms (9281E; Kistler, Winterthur, Switzerland) was used to collect

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Jonathan Sinclair and Paul J. Taylor

piezoelectric force platform (Kistler; Kistler Instruments Ltd, Hampshire, United Kingdom) that sampled at 1000 Hz. Dynamic calibration of the motion capture system was performed before each data collection session. Figure 1 —Experimental prophylactic knee brace. Lower-extremity segments were modeled in 6 df

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Rachel L. Wright, Joseph W. Bevins, David Pratt, Catherine M. Sackley and Alan M. Wing

: Values are in mean (SD). All testing occurred during a single laboratory session and comprised both un-cued and cued stepping in place. Participants stepped on 2 force platforms, with 1 foot on each force platform. Participants were asked to step in place at their comfortable speed for 20 seconds to

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Anis Kamoun, Omar Hammouda, Abdelmoneem Yahia, Oussema Dhari, Houcem Ksentini, Tarak Driss, Nizar Souissi and Mohamed Habib Elleuch

starting from 0 with an increment of 3 during measurement period. Posturographic analysis of dynamic balance was performed using a cylindrical stabilometer with a single degree of freedom. A 48- × 48-cm balance board was placed on the force platform. The two parallel arcs on the underside of the board had

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Samuele Contemori, Andrea Biscarini, Fabio M. Botti, Daniele Busti, Roberto Panichi and Vito E. Pettorossi

volleyball players with IIMA and in healthy controls, through the assessment of the shoulder static stability with the use of force platforms and the shoulder dynamic stability with the Upper Quarter Y Balance Test (UQYBT). Methods Design A cross-sectional design was used. Participants A total of 24 male