Flying high: Isometric strength training increases time of flight in junior elite trampoline gymnasts

The purpose of this study was to assess the effects of a 6-week isometric training intervention on time of flight (ToF) in elite youth level gymnasts. Fourteen nationally elite youth gymnasts (10 females and 4 males; age = 15 ± 2 years; mass = 55.0 ± 8.2 kg and stature = 163.7 ± 6.5 cm) were recruited. Seven gymnasts in the intervention (INT) group performed a 6-week isometric squat strength-training programme, replacing heavy maximal lower limb exercises with three isometric exercises. Seven gymnasts in the control (CON) group performed a standardised strength programme. All gymnasts performed habitual trampoline training. Pre- and post-testing included cycling peak power output, isometric strength, countermovement jumps and 20-maximum ToF jump tests. Changes in ToF were greater for the INT group (+0.83 s; 2.8%) compared to the CON group (+0.06 s; +0.2%), with a significant group × time interaction effect on ToF (p = 0.021). The change in isometric squat peak force at 150° in the INT group (+379 N; 22.4%) was different to the change in the CON group (+78 N; 5.0%), with a significant group × time interaction effect (p = 0.032). The isometric intervention provided a sport-specific training stimulus that was better than traditional heavy maximal resistance training alone for improving isometric strength and ToF in elite trampoline gymnasts.