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Pai-Yun Cheng, Hsiao-Feng Chieh, Chien-Ju Lin, Hsiu-Yun Hsu, Jia-Jin J. Chen, Li-Chieh Kuo and Fong-Chin Su

-extremity functions ( Liu et al., 2017 ; Shiffman, 1992 ). Muscle strength will be restrained by the number and mechanical properties of motor units ( Carmeli, Patish, & Coleman, 2003 ), and reduced sensory inputs might affect the sensorimotor coordination and force control of older adults ( Cole, 1991 ). Decreasing

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John J. McMahon, Paul A. Jones, Timothy J. Suchomel, Jason Lake and Paul Comfort

The Reactive Strength Index (RSI) accounts for the duration of force production to achieve a given jump height by dividing jump height by ground-contact time. 1 RSI is a more easily obtainable metric than force-platform-derived variables, and it provides greater insight into neuromuscular and

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


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.


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.


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.


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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Gemma N. Parry, Lee C. Herrington and Ian G. Horsley

important to identify ways of assessing an athlete’s ability to produce upper-limb force in order to not only understand an individual’s performance potential but also monitor training program effects, long-term development, and talent identification. Despite the importance of upper-limb muscular power

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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

been conducted to investigate the effects of different training methods on acceleration and maximal sprint capacities. 5 – 9 A new training approach based on the force–velocity (F–V) profile has gained in popularity over recent years to enhance sprint performance. 10 , 11 The F–V profile in sprinting

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Abderrahmane Rahmani, Pierre Samozino, Jean-Benoit Morin and Baptiste Morel

Bench-press exercise is often used as a simple test to evaluate the upper-limb force, velocity, and power output. 1 – 3 These muscle parameters are usually determined using a force platform 4 , 5 or kinematic systems such as optical encoders 6 , 7 or linear transducers. 1 , 8 – 10 Although

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

focused on muscular strength and power output. 4 , 5 , 8 , 11 Over the last few years, new findings and field methods in ballistic actions have highlighted the importance of measuring the relationship between force and velocity mechanical capabilities during jumping performance, known as the force

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Tomoko Aoki, Hayato Tsuda and Hiroshi Kinoshita

abilities to control grip force appropriately tuned for given friction between the digits and object held by the two digits ( Cole, 1991 ), and to control the force directions by the two digits and the moments acting on freely movable objects ( Parikh & Cole, 2012 ). Ranganathan, Siemionow, Sahgal, and

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Ryan Morrison, Kyle M. Petit, Chris Kuenze, Ryan N. Moran and Tracey Covassin

diagnostic accuracy and reliability. Due to the subjective nature of these tests, a force plate is considered the gold standard because of its objective outcome. 6 Force-plate analysis allows for the athlete center of pressure (COP) to be calculated based on the foot contact of an individual while on the

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Mark L. Latash, Fan Gao and Vladimir M. Zatsiorsky

The method of multidimensional scaling was applied to matrices of finger interaction (IFM) computed for individual participants for finger force production tasks. When IFMs for young controls, elderly, and persons with Down syndrome were pooled, only two dimensions described interpersonal differences; these were related to total force and to the total amount of enslaving. When IFMs for each group were analyzed separately, subpopulation-specific dimensions were found. Potentially, this analysis can be applied to discover meaningful dimensions that reflect differences in indices of finger interaction across and within subpopulations which differ in their apparent ability to use the hand. It may also be useful for tracking changes in finger interaction that occur in the process of specialized training or motor rehabilitation.