MUSCLE COORDINATION DURING SIDESTEP CUTTING. CAN THE COORDINATION BE INFLUENCED BY PROPHYLACTIC TRAINING?

INTRODUCTION The incidence. of anterior cruciate ligament (ACL) injuries is reported to be high during the popular team sports like soccer, basketball, volleyball and team handball.The most highly risked movement in team handball is reported to be the sidestep cutting maneuver (Strand, 1990. Well-rehabilitated ACL-deficient athletes have been shown to have increased co-contraction about the knee joint (Walla, 1985). The aim of this study was to examine the effect of a prophylactic training program on the co-contraction of non-injured team handball players. METHODS 16 male subjects were divided into a test group (9 subj.) and a control group (7 subj.). The test group performed 5 different exercises under supervision, twice a week for 12 weeks. The exercises consisted of 1)one-legged squats, 2)ham-string pulls, 3)hip abductions, 4)one-legged 'coordination jumps' where the test subject should repetitively hit special marks on the floor without losing his balance 5)one-legged jumps to the side, and. The exercises were designed in a progressive manner in order to increase the strain on the athletes during the whole training period. All exercises are widely used at different stages of the rehabilitation of ACL-deficient patients. To measure the co-contraction EMG-electrodes were applied on 6 selected muscles, influencing the knee. The subjects then performed 10 repetitions of a sidestep cutting maneuver similar to their normal 'match-like' cutting maneuver on a forceplatform and the EMG-signals and the forceplatform signals were simultaneously stored on a personal computer. Maximal voluntary contractions and the corresponding EMG activity were measured for each muscle group. RESULTS The test group showed a significantly shorter ground contact phase after the training (