Adjustments in Motor Unit Properties during Fatiguing Contractions after Training

• DOI: 10.1249/mss.0b013e318235d81d
• Publication Date: 2011-10-04T19:38:12Z
• Authors: CAROLINA VILA-CHÃ; DEBORAH FALLA; MIGUEL VELHOTE CO...; DARIO FARINA
• Keywords: Motor unit; Endurance Training; Vastus medialis; Motor Unit Recruitment; Coactivation; Strength Training

Objective The objective of the study was to investigate effect strength and endurance training on muscle fiber membrane properties discharge rates low-threshold motor units vasti muscles during fatiguing contractions. Methods Twenty-five sedentary healthy men (age (mean ± SD) = 26.3 3.9 yr) were randomly assigned one three groups: training, or a control group. Conventional performed 3 d·wk−1, period 6 wk. Motor unit conduction velocity EMG amplitude vastus medialis obliquus lateralis biceps femoris measured sustained isometric knee extensions at 10% 30% maximum voluntary contraction before immediately after training. Results After wk reduction in contractions force occurred slower compared with baseline (P < 0.05). However, rate decrease lower 0.01). For all groups, declined 0.001), their trend not altered by In addition, femoris–vasti coactivation ratio Conclusions Short-term induces alterations electrophysiological fiber. particular, lowers decline more than