Influence of the Reactive Strength Index Modified on Force– and Power–Time Curves
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TL;DR: Athletes who perform the CMJ with a high RSImod, as achieved by high jumps with a short TTT, demonstrate superior force, power, velocity, and impulse during both the eccentric and concentric phases of the jump.
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Abstract: Purpose:The reactive strength index modified (RSImod) has been recently identified and validated as a method of monitoring countermovement jump (CMJ) performance. The kinetic and kinematic mechanisms that optimize a higher RSImod score are, however, currently unknown. The purpose of this study, therefore, was to compare entire CMJ force-, power-, velocity- and displacement-time curves (termed temporal phase analysis) of athletes who achieve high versus low RSImod scores. Methods:Fifty-three professional male rugby league players performed three maximal effort CMJs on a force platform and variables of interest were calculated via forward dynamics. RSImod values of the top (high RSImod group) and bottom (low RSImod group) twenty athletes’ kinetic and kinematic-time curves were compared. Results:The high RSImod group (0.53±0.05 vs. 0.36±0.03) jumped higher (37.7±3.9 vs. 31.8±3.2 cm) with a shorter time to take-off (TTT) (0.707±0.043 vs. 0.881±0.122 s). This was achieved by a more rapid unweighting phase foll...
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Citations
Understanding the key phases of the countermovement jump force-time curve
TL;DR: Six key phases of the countermovement jump (CMJ) can be derived from force-time records to facilitate researchers’ and practitioners’ understanding and application to their own practice.
Phase-Specific Predictors of Countermovement Jump Performance That Distinguish Good From Poor Jumpers.
TL;DR: Individuals targeting enhanced CMJ performance may consider exploring strategies or interventions to develop quicker unloading and concentric phases and increasing eccentric RFD abilities.
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Relationship between reactive strength index variants in rugby league players
TL;DR: It is suggested that the two RSI variants do not explain each other well, indicating that they do not assess entirely the same reactive strength qualities and should not be used interchangeably.
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Influence of Dynamic Strength Index on Countermovement Jump Force-, Power-, Velocity-, and Displacement-Time Curves.
John J. McMahon,Paul A. Jones,Thomas Dos'Santos,Paul Comfort +3 more
- 23 Sep 2017
TL;DR: The notion of ballistic versus maximal strength training likely being better suited to low versus high DSI scorers, respectively, is supported, taken together with those of previous studies.
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Relationships between Isometric Force-Time Characteristics and Dynamic Performance
Thomas Dos'Santos,Christopher Thomas,Paul Comfort,John J. McMahon,Paul A. Jones +4 more
- 13 Sep 2017
TL;DR: The findings highlight that the ability to apply rapidly high levels of force in short time intervals is integral for PC, CMJ height, and reactive strength.
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TL;DR: The CMJ test appears a suitable athlete-monitoring method for NM-fatigue detection, but the current approach (ie, CMJ-TYP) may overlook a number of key fatigue-related changes, and so practitioners are advised to also adopt variables that reflect the NM strategy used.
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