OBJECTIVE. To investigate whether patients with fibromyalgia (FM)
have normal motor unit recruitment in relation to muscle
metabolism during exhausting exercise and recovery, and
whether the reduced voluntary muscle force normally seen is
related to a smaller muscle size.
METHODS. Female patients
with FM and sedentary controls were examined using
simultaneous 31P nuclear magnetic resonance spectroscopy (NMR)
and surface electromyography (SEMG) during exhaustive static
exercise of the anterior tibial muscle and during recovery.
The maximum voluntary contraction force was estimated, and the
maximum cross sectional muscle area was evaluated using 1H NMR
imaging. The sedentary controls were matched to patients for
sex, age and, as far as possible, daily physical activity
RESULTS. Patients with FM had reduced maximum
voluntary contraction force in relation to the sedentary
controls, despite having similar muscle size. In general the
myoelectrical-metabolic relation during exercise and recovery
was normal in patients with FM.
CONCLUSION. The less extreme
changes in motor unit recruitment and metabolism during
exhaustive exercise indicated a lower exercise tolerance that
could be connected with the lower physical activity levels.
Vestergaard-Poulsen P, Thomsen C, Norregaard J, Bulow P, Sinkjaer T,