Increased rate of force development and neuromuscular activity after high-load resistance training in patients undergoing dialysis.

AIM: The aim of this study was to investigate the effects of high-load resistance training on the rate of force development and neuromuscular function in patients undergoing dialysis.

METHODS: Twenty-nine patients were tested before and after 16 weeks of resistance training. The rate of force development was tested using the Good Strength dynamometer chair. Muscle strength and neuromuscular function in the m. Vastus lateralis was estimated using electromyography in a one repetition maximum test during dynamic knee extension and during a 20 s isometric knee extension with 50% of the one repetition maximum load. Muscle biopsies from the m. Vastus lateralis were analysed for morphologic characteristics.

RESULTS: One repetition maximum in knee extension increased by 46% (P<0.001) after the training programme. Rate of force development increased by 21-38% (P<0.05). The electromyography amplitude increased during 200-300 msec from 183 ± 36 μV to 315 ± 66 μV, (P<0.05), whilst electromyography frequency remained unchanged. The electromyography signals, during isometric contractions, remained unchanged. A higher rate of force development was found to be significantly associated with larger type 2 muscle fibres (r=0.647).

CONCLUSION: Muscle strength in patients undergoing dialysis was increased after 16 weeks of resistance training in parallel with changed neuromuscular function and greater rate of force development, both of which have important clinical implications in terms of improved physical performance.