Voluntary activation during knee extensions in severely deconditioned patients with chronic obstructive pulmonary disease: Benefit of endurance training

Vivodtzev I, Flore P, Levy P, Wuyam B

As a consequence of hypoxaemia or detraining, a deficit in voluntary activation may contribute to the reduction in strength in chronic obstructive pulmonary disease (COPD).  This was studied in 13 severely deconditioned COPD patients and 8 healthy subjects.  Exercise tolerance, fat-free mass and quadriceps maximal voluntary contractions (MVC) were evaluated.  Magnetic stimulation was used to measure maximal quadriceps twitch tension (TwQp) at rest and during a voluntary contraction (TwQs).  After rehabilitation patients had a greater MVC. Deficit in voluntary activation of quadriceps muscle may therefore contribute to muscle weakness in severe COPD patients and is reversed by training.

Muscle and Nerve, 2007, online article ahead of press

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