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Enhanced physiological tremor deteriorates plantar flexor torque steadiness after bed rest

journal contribution
posted on 2011-04-01, 00:00 authored by E R Mulder, A M Horstman, K Gerrits, M Massa, B U Kleine, A de Haan, Daniel BelavyDaniel Belavy, D Felsenberg, M Zwarts, D F Stegeman
This study evaluated the effectiveness of resistance training to preserve submaximal plantar flexor (PF) torque steadiness following 60 days of bed rest (BR). Twenty-two healthy male subjects underwent either BR only (CTR, n=8), or BR plus resistance training (RT, n=14). The magnitude of torque fluctuations during steady submaximal isometric PF contractions (20%, 40%, 60% and 80% of maximum) were assessed before and after BR. Across contraction intensities, torque fluctuations (coefficient of variation, CV) increased more (P<0.05) after BR for CTR (from 0.31±0.10 to 0.92±0.63; P<0.001), than for RT (from 0.30±0.09 to 0.54±0.27; P<0.01). A shift in the spectral content of torque fluctuations towards increased rhythmic activity between 6.5 and 20Hz was observed in CTR only (P<0.05). H-reflex amplitude (H(max)/M(max) ratio) declined across groups from 0.57±0.18 before BR to 0.44±0.14 following BR (P<0.01) without correlation to CV. The present study showed that increased torque fluctuation after BR resulted from enhanced physiological tremor. Resistance training prevented the spectral shift in isometric PF torque fluctuation and offset ∼50% of the decline in performance associated with long-term BR.

History

Journal

Journal of electromyography and kinesiology

Volume

21

Issue

2

Pagination

384 - 393

Publisher

Elsevier

Location

Amsterdam, The Netherlands

eISSN

1873-5711

Language

eng

Publication classification

C1.1 Refereed article in a scholarly journal

Copyright notice

2010, Elsevier