THE EFFECTS OF ROPE SKIPPING ON MOVEMENT CO-ORDINATION IN CHILDREN - AN ELECTROMYOGRAPHY STUDY
Keywords: rope skipping, EMG, coordination, children
AbstractINTRODUCTION: The issue of rope skipping as a method of fitness training is of great concern to the community. But little is known about the effects of rope skipping on the coordination ability of children. The purpose of this study was to examine the effects in terms of EMG responses of eight weeks of rope skipping exercises on the coordination ability of school children. METHODS: Twenty male Form 5 school students who did not have rope skipping experience were randomly recruited from a secondary school and formed paired exercise- and control groups, in accordance with the Body Mass Index. The age, body height and body weight of the exercise group were 15.60±0.52 years, 173.83±5.05 cm and 59.93±5.73 kg, and for the control group 15.70±0.68 years, 170.28±6.05 cm and 55.20±6.49 kg respectively. The subjects in the exercise group took part in rope skipping for eight weeks, 5 times weekly, twenty minutes each time, and at an intensity that produced a mean heart rate of an estimated 75% of maximal oxygen uptake. The subjects in the control group did not participate in any programmed exercise except the physical education courses for all students in the school. Two testing sessions were arranged for both groups: one week before and one week after the training program. In each session, the subjects were asked to perform rope skipping for 10 minutes at a rate which induced the heart rate of each subject to reach its maximal value. During testing, the remote EMG signals of eight muscles on the leg were detected and full-wave rectified. The duration of each muscle’s contraction and the timing sequence of the contraction among different muscles were calculated for the supporting phase. T-tests were used to examine the differences in the data to be compared. RESULTS: The trained group showed significantly shorter duration in vastus medialis contraction than the untrained group (p<.001). Also, the trained group showed a greater time gap in the muscle contraction between quadriceps (vastus medialis, rectus femoris and vastus lateralis) and tibialis anterior when jumping up, and between tibialis anterior (landing) and gastrocnemius (jumping). CONCLUSIONS: For the same intensity of exercise, a shorter working time for muscles results in less energy expenditure. Under the same frequency of rope skipping, greater time gaps between the consecutive contractions of muscles may provide more resting time for the muscles and therefore save the energy expended. It could be concluded that programmed rope skipping exercise can improve movement coordination and reduce energy expenditure.
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