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.