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The Relationship between Maximal-Strength and Reactive-Strength.

Research paper by Kris K Beattie, Brian P BP Carson, Mark M Lyons, Ian C IC Kenny

Indexed on: 13 Sep '16Published on: 13 Sep '16Published in: International journal of sports physiology and performance



Abstract

Maximum- and reactive-strength qualities both have important roles in athletic movements and sporting performance. Very little research has investigated the relationship between maximum-strength and reactive-strength. The aim of this study was to investigate the relationship between maximum-strength (isometric mid-thigh pull peak force; IMTP PF) and reactive-strength (drop-jump reactive-strength index; DJ-RSI) variables at 0.3 m, 0.4 m, 0.5 m and 0.6 m box heights. A secondary aim investigated the between- and within-group differences in reactive-strength characteristics between relatively 'strong' and 'weak' athletes. Forty-five collegiate athletes across various sports were recruited to participate in the study (age: 23.7 ± 4.0 years; mass: 87.5 ± 16.1 kg; height: 1.80 ± 0.08 m). Pearson's correlation results showed that there was a moderate association (r = 0.302 - 0.431) between maximum-strength variables (absolute, relative & allometric scaled PF) and RSI at 0.3, 0.4, 0.5 and 0.6 m (p ≤ 0.05). In addition, two-tailed independent samples t tests showed that relatively stronger athletes (n = 11; 49.59 ± 2.57 N·kg-1) had significantly larger RSI than weaker athletes (n = 11; 33.06 ± 2.76 N·kg-1) at 0.4 m (Cohen's d = 1.02), 0.5 m (d = 1.21) and 0.6 m (d = 1.39) (p ≤ 0.05). Weaker athletes also demonstrated significant decrements in RSI as eccentric stretch loads increased from 0.3 to 0.6 m box heights, whereas strong athletes were able to maintain their reactive-strength ability. This research highlights that in specific sporting scenarios, where there are high eccentric stretch-loads and fast stretch-shortening cycle (SSC) demands, an athlete's reactive-strength ability may be dictated by their relative maximal-strength, specifically their eccentric strength.