Changes in H reflex and V wave following short-term endurance and strength training

Research output: Contribution to journalArticlepeer-review

Authors

  • Carolina Vila-Chã
  • Deborah Falla
  • Miguel Velhote Correia
  • Dario Farina

Colleges, School and Institutes

External organisations

  • Polytechnic Institute of Bragança, Bragança, Portugal.

Abstract

This study examined the effects of 3 wk of either endurance or strength training on plasticity of the neural mechanisms involved in the soleus H reflex and V wave. Twenty-five sedentary healthy subjects were randomized into an endurance group (n = 13) or strength group (n = 12). Evoked V-wave, H-reflex, and M-wave recruitment curves, maximal voluntary contraction (MVC), and time-to-task-failure (isometric contraction at 40% MVC) of the plantar flexors were recorded before and after training. Following strength training, MVC of the plantar flexors increased by 14.4 ± 5.2% in the strength group (P < 0.001), whereas time-to-task-failure was prolonged in the endurance group (22.7 ± 17.1%; P < 0.05). The V wave-to-maximal M wave (V/M(max)) ratio increased significantly (55.1 ± 28.3%; P < 0.001) following strength training, but the maximal H wave-to-maximal M wave (H(max)/M(max)) ratio remained unchanged. Conversely, in the endurance group the V/M(max) ratio was not altered, whereas the H(max)/M(max) ratio increased by 30.8 ± 21.7% (P < 0.05). The endurance training group also displayed a reduction in the H-reflex excitability threshold while the H-reflex amplitude on the ascending limb of the recruitment curve increased. Strength training only elicited a significant decrease in H-reflex excitability threshold, while H-reflex amplitudes over the ascending limb remained unchanged. These observations indicate that the H-reflex pathway is strongly involved in the enhanced endurance resistance that occurs following endurance training. On the contrary, the improvements in MVC following strength training are likely attributed to increased descending drive and/or modulation in afferents other than Ia afferents.

Details

Original languageEnglish
Pages (from-to)54-63
Number of pages10
JournalJournal of Applied Physiology
Volume112
Issue number1
Publication statusPublished - Jan 2012

Keywords

  • Adult, Afferent Pathways, Electromyography, Female, H-Reflex, Humans, Male, Muscle Contraction, Physical Endurance, Resistance Training, Time Factors, Young Adult, Journal Article, Randomized Controlled Trial, Research Support, Non-U.S. Gov't