The effectiveness of a pendulum swing for the development of leg strength and counter-movement jump performance.

Various training devices have been developed to facilitate 'plyometric' training, one such device being the 'pendulum swing'. To assess the effectiveness of the pendulum swing, the results of a 3 week training programme using a combination of pendulum swing and weight-training exercises were compared to those of a weight-training programme. Subjects were assigned to one of two groups (n = 9) for weight-training only or for combined pendulum and weight-training. Both groups performed the same number of exercise repetitions. Measurements of isometric knee and hip extension-flexion, 1-RM squat weight, maximum jump height and power for a counter-movement jump were taken pre-training, 2 days after the end of the programme and 2 weeks after the end of the programme. The data were analysed using two-way MANOVA and MANCOVA techniques. Both methods showed significant (P < 0.05) increases in knee and hip extension strength. Hip and knee flexion strength increased only for the weight-trained group. Counter-movement jump height increased for both groups (weight-trained, P < 0.05; combined, P < 0.01). Maximum power increased only for the combined group (P < 0.05). When the pre-training scores were used as a covariate, the weight-trained group showed a greater increase in hip flexion and extension strength and knee flexion strength than the combined training group (P < 0.05). The combined group showed the greatest increase in knee extensor strength. It is concluded that the pendulum system induces a training effect which could be used to supplement weight-training for improving vertical jump performance.