A kinetic and kinematic assessment of the band assisted countermovement jump

This study sought to elucidate kinetic and kinematic differences between unloaded and band assisted countermovement jumps (CMJ). In a randomised order, 20 healthy subjects (mass 84.5±18.6 kg) completed 3 repetitions of CMJs across three conditions; unloaded (at body mass), low and moderate band (8.4±1.9 and 13.3±3.3 kg body mass reduction, respectively). For all repetitions, a force platform and linear position transducer were used to record and calculate kinetic and kinematic data during the eccentric, concentric, and landing phases. Body weight was significantly different between the unloaded, low, and moderate band conditions (P<0.05). Peak velocity, absolute peak and mean force  and movement duration displayed a trend that was mostly related to the condition (i.e. unloaded> low>moderate) (P<0.05). The opposing trend (i.e. moderate>low>unloaded) was generally observed for relative peak and mean force, reactive strength index modified and flight time (P<0.05). No differences were observed for mean velocity, movement duration and absolute and relative landing forces (P>0.05). The use of band assistance during CMJs can alter force, time and velocity variables. Practitioners should be aware of the potential positive and negative effects of band assistance during CMJs.