Upright versus Horizontal Squat Jumps: A comparison of peak force, peak velocity, peak power and muscle activity in male athletes

Abstract

Sports performance coaches and rehabilitation specialists commonly prescribe explosive squat jumps (SJ) in the upright position to improve lower body power using loads based upon an individual’s one-repetition maximum (1RM) back squat. Recently, using a horizontal leg press to perform SJ has become popular purportedly due to its less technical nature. To date, little research exists comparing upright and horizontal SJ. Therefore, this investigation examined peak force, peak velocity, peak power and muscle activity of upright versus horizontal SJ using loads based upon each condition’s respective 1RM. Twelve males completed two sets of three repetitions of SJ at 20%, 30%, 40%, 50% and 60%1RM. Statistical significance was set to P ≤ 0.05. No significant differences existed between trial 1 and 2 for any measures. Two-way analysis of variance revealed a) no significant difference in peak force between the SJ conditions at any intensity; b) significantly greater peak velocity during upright SJ at all intensities; c); significantly greater peak power during upright SJ at all intensities; and d) no difference in muscle activity between SJ conditions. In conclusion, in a key measure of performance, power output during upright SJ was significantly greater than during horizontal SJ.