HALF-SQUAT AND JUMP-SQUAT EXERCISES PERFORMED ACROSS A RANGE OF LOADS: DIFFERENCES IN MECHANICAL OUTPUTS AND STRENGTH DEFICITS.

The aim of this study was to compare the peak-force (PF), peak-power (PP), and peak velocity (PV) outputs produced during half-squat (HS) and jump-squat (JS) exercises executed at 20, 40, 60, and 80% of one-repetition maximum (1RM) in the HS (HS 1RM); and to compute and compare the strength deficit (SDef) achieved in these exercises across these loads. Twenty-four national rugby union players (age: 25.7 ± 3.6 years) performed HS-1RM and a progressive loading test in the HS and JS exercises. The PF, PP, and PV values were obtained in all loads for both exercises and the SDef was calculated as the percentage difference between the PF at distinct relative intensities and the PF at HS-1RM. The differences in HS and JS variables were determined using an analysis of variance with repeated measures. Higher PF, PP, and PV outputs were generated in the JS in comparison with the HS exercise (P<0.05); moreover, the SDef magnitudes were significantly lower in the JS (P<0.01), for all loading conditions. Importantly, the differences in SDef, and as a consequence, in PF, PP, and PV decreased progressively with increasing load. Overall, the loaded JS exhibited increased levels of PF, PP, and PV and reduced levels of SDef when compared to the traditional HS performed across a range of loads. The JS is indicated to reduce the SDef and improve the athletes’ ability to apply force at higher velocities. Nevertheless, with heavier loads (i.e., ≥ 80% HS-1RM), its potential advantages and effectiveness may be seriously compromised.