Does acute passive stretching alter the optimum height for drop jumping?

The application of static stretching (SS) has previously been shown to limit performance in force production, reaction time, balance and vertical jump height. When looking at the effect of SS on jump performance, researchers have previously used changes in jump height, in squat jumps (SQ), countermovement jumps (CMJ) and drop jumping (DJ) from self selected heights. To date no one has looked at the effect of SS across a range of drop heights. 30 subjects (15 male and 15 female) participated in 1 familiarization trial and four performance trials. All subjects undertook two days of stretching (ST) and two days of non-stretching (NS), in randomized fashion. The stretching protocol involved five lower body stretches. Each stretch was taken to the point of discomfort (POD) and held for 15 seconds with a rest period of 15 seconds, three times. Each stretch was performed both unassisted and assisted. This was followed by 10 minutes of quiet sitting. The NS group rested for a total of 33 minutes and 30 seconds. Both groups performed a sit and reach test on arrival and after the ST protocol / NS protocol. Each subject performed a total of 12 jumps from 6 different heights with 30 seconds rest between each jump per trial. Jump heights were calculated and ground contact times (GCT) measured using the AMTI force platform system. Two-way analysis of variance revealed that SS did not alter maximal vertical jump height (p \u3e 0.05). Therefore this study has demonstrated that a lower body SS program (5 stretches, 90 seconds per stretch) did not alter DJ height