Effect of plyometric training and subsequent detraining on changes in force-velocity relationship

The purpose of this study was to investigate the effect of plyometric training and subsequent detraining on changes in force-velocity relationship.

Forty active students (mean±SD, age, 24±2.3 years; weight, 75±5.6 kg; height, 176±8.3 cm) participated in this study. Subjects were divided into control and experimental groups. The Biodex and EMG were used to measure muscle contraction velocity and to assess muscle electrical activity. Subjects in control group were asked to continue their daily activities; while, subjects in experimental group participated in a 6-week plyometric training program. Data were collected at pre-training, post-training and post-detraining. The independent t-test, repeated measures of ANOVA and Tukey's post-hoc tests were used for data analysis.

In the experimental group, a significant increase in EMG activity was observed in response to training for all movements (P>0.05); while the EMG activity was significantly decreased in slow and moderate movements during detraining (P<0.05). No significant differences were observed in EMG activities of control group for all movements and periods (P 0.05).

It seems that reductions in EMG activities of muscles were due to insufficient intensity of movements, because applying maximal velocity movements resulted in the maintenance of training induced physiological adaptations.