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Garrett M. Hester, Zachary K. Pope, Mitchel A. Magrini, Ryan J. Colquhoun, Alejandra Barrera-Curiel, Carlos A. Estrada, Alex A. Olmos and Jason M. DeFreitas

output are 2–3 times more likely to demonstrate mobility limitations compared with those with low muscle strength alone ( Bean et al., 2003 ). Given the components of power, a decrease in either contraction velocity or force will result in reduced power output. Indeed, maximal velocity parameters such as

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Marianne J.R. Gittoes and Cassie Wilson

This study aimed to develop insight into the lower extremity joint coupling motions used in the maximal velocity phase of sprint running. Two-dimensional coordinate data were used to derive sagittal plane joint angle profiles of sprint running trials. Intralimb joint coupling motions were examined using a continuous relative phase (CRP) analysis. The knee-ankle (KA) coupling was more out of phase compared with the hip-knee (HK) coupling across the step phase (mean CRP: KA 89.9° HK 34.2°) and produced a lower within-athlete CRP variability (VCRP) in stance. Touchdown (TD) produced more out-of-phase motions and a larger VCRP than toe-off. A destabilization of the lower extremity coordination pattern was considered necessary at TD to allow for the swing-to-stance transition. The key role that the KA joint motion has in the movement patterns used by healthy athletes in the maximal velocity phase of sprint running was highlighted.

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Pedro Jiménez-Reyes, Fernando Pareja-Blanco, David Rodríguez-Rosell, Mario C. Marques and Juan José González-Badillo

Purpose:

To determine what variables determine the differences in performance on 2 tests of squat jump (SJ) performed under light load in highly trained athletes using maximal velocity (Vmax) or flight time (FT) as the discriminating factor of SJ performance.

Methods:

Thirty-two participants performed 2 maximal weighted SJs using a force platform synchronized with a linear transducer. Mean force (Fmean), mean and maximal power (Pmean, Pmax), peak force (PF), maximal rate of force development (RFDmax), and time required to attain PF (TPF) and RFDmax (TRFDmax) were analyzed. SJs were divided into 2 segments: from the initiation of force application to PF1 and from the moment after PF1 to Vmax.

Results:

Traditional significance statistics revealed significant differences in the same variables between best and worst SJs using both FT and Vmax. However, to use an approach based on the magnitude of the effect, the best SJ showed greater Pmax (83/17/0%), Pmean (85/15/0%), Fmean (71/29/0%), RFDmax1 (73/27/0%), and PF1 (53/47/0%) and lower TPF2 (0/61/39%) than the worst SJ when Vmax was used to discriminate SJ performance. However, using FT to differentiate SJ performance, no difference was observed between best and worst.

Conclusions:

Although jump height assessed through FT is a valid measure, these results suggest that Vmax is a more sensitive variable than FT to detect differences in loaded-SJ performance.

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Pedro Jiménez-Reyes, Amador García-Ramos, Victor Cuadrado-Peñafiel, Juan A. Párraga-Montilla, José A. Morcillo-Losa, Pierre Samozino and Jean-Benoît Morin

players, while the number of sprints that are performed at or close to maximal velocity are higher in soccer. 4 These differences could be caused by the smaller dimensions of futsal fields (40 × 20 m) as compared with soccer fields (≈105 × 70 m) as well as by the lower number of players involved in

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Yeshayahu Hutzler, Martin Grunze and Rolf Kaiser

Eleven male elite wheelchair basketball players took part in an all-out, high-velocity, “Wingate”-type ergometric test lasting 30 s. An electrically braked and electronically controlled roller device was used to measure power and velocity. A breath-by-breath metabolic measurement cart collected net O2 uptake prior to, during, and after the test. Average braking load and velocity were 9.91 N · m and 5.09 m · s-1, respectively. Mean total work during the test was 4,468.47 ± 1,326 J. Based on net O2 cost and estimating a 10% efficiency, the aerobic contribution would be 29.8 ± 10.2%. Therefore, performance in this test seems to be predominantly anaerobic. Velocity variables of the subjects included in this study had a significant relationship to power variables and thus are considered valid for measuring peak performance, mean performance, and fatigue. A regression analysis utilizing wheel size and function as independent variables presented a significant relationship to peak velocity (P <.005). Further findings indicated variability in technique among subjects that led to training suggestions.

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Fergus O’Connor, Heidi R. Thornton, Dean Ritchie, Jay Anderson, Lindsay Bull, Alex Rigby, Zane Leonard, Steven Stern and Jonathan D. Bartlett

high maximal velocity but a low maximal aerobic speed may work harder for a given percentage of maximal velocity, compared with an athlete who may have a low maximal velocity but high maximal aerobic speed. Nevertheless, in rugby league, high-speed running distance covered using an absolute threshold

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Dean Ritchie, Justin Keogh, Steven Stern, Peter Reaburn, Fergus O’Connor and Jonathan D. Bartlett

obtained were TD (in meters), total high-speed running (HSR) >15 km·h −1 (in meters), TD above 75% of an individual’s maximum velocity (in meters), TD above 85% of an individual’s maximum velocity (in meters), and mean speed (in meters per minute). Maximal velocities were obtained as previously described

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Thomas Haugen, Jørgen Danielsen, Leif Olav Alnes, David McGhie, Øyvind Sandbakk and Gertjan Ettema

, 4 – 6 the acceleration phase, 7 – 10 or during the maximal velocity phase, 11 – 13 typically assessing 1 to 3 steps. Only a few scientific studies have investigated the kinematics of athletic sprinting based on high-resolution assessments of >6 steps. 14 – 16 However, none of these

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Juan A. Escobar Álvarez, Juan P. Fuentes García, Filipe A. Da Conceição and Pedro Jiménez-Reyes

enhance jump performance while reducing the actual F-V IMB . 15 – 17 The actual and the optimal F-V profile can be computed during a series of loaded vertical jumps. 20 – 24 This field method provides the information related to theoretical maximal force ( F 0 ), theoretical maximal velocity ( V 0

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Marcus J. Colby, Brian Dawson, Peter Peeling, Jarryd Heasman, Brent Rogalski, Michael K. Drew and Jordan Stares

only lower-body noncontact injury resulting in matches missed was included. This definition of injury is comparable to a competition, sports incapacity injury. 23 , 24 Previously validated objective (global positioning system derived; total distance, sprint distance, and maximal velocity) and