Effects of 4-week slackline training on lower limb joint motion and muscle activation

ObjectivesTo investigate the effects of four weeks of slacklining on lower limb kinematics and muscle activity following a slip of the upright stance.DesignA randomized, gender matched study.MethodsTwenty-four young healthy adults participated in the study and were assigned to either a training or a control group. The training group completed a 4-week training program on slacklines, while the control group received no slackline training. Before and after training, participants performed single leg standing tasks on a moveable platform. During medio-lateral platform perturbation, platform displacement, lower limb joint motion (ankle, knee and hip) and surface electromyography (EMG) measurements from six lower limb muscles were recorded.ResultsIn the training group, a decrease in platform mean and maximum velocity (all p < 0.05) was detected, but no changes were observed for the release time and maximum deflection (all p > 0.05) of the platform. Regarding lower limb kinematics, a reduced corrective action was detected in the knee joint (p < 0.05), whereas only a trend towards a decrease could be observed in the ankle joint (p < 0.1). EMG data revealed an enhanced activation of the rectus femoris (p < 0.05), as well as a trend to increased rectus femoris to biceps femoris co-activation (p = 0.06) in the preparatory phase for training group.ConclusionsThe data strongly support that slacklining can improve postural control and enhance functional knee joint stability, which seems to be induced by enhanced preparatory muscle activation of the rectus femoris.