Neuromuscular function after muscle fatigue in Charcot-Marie-Tooth type 1A patients.
BACKGROUND
The effect of recovery time on neuromuscular function after a fatiguing task was compared in both the upper and lower limbs between patients with Charcot-Marie-Tooth type 1A (CMT1A) and healthy individuals.


METHODS
Torque of elbow flexors and knee extensors and surface electromyography (sEMG) data of biceps brachii and vastus lateralis were recorded from 8 CMT1A patients and 8 matched, healthy individuals during maximal voluntary contraction (MVC) before (pre-fatigue MVC), 10 s after (10-s post-fatigue MVC), and 10 min after (10-min post-fatigue MVC) a fatiguing task at 80% MVC until exhaustion.


RESULTS
Only in the lower limb, torque and root mean square of sEMG (RMS) during pre-fatigue MVC were lower (P < 0.05) in patients (91.93 ± 45.95 Nm, 0.11 ± 0.07 mV) than in controls (161.06 ± 75.5 Nm, 0.24 ± 0.16 mV). In the 10-min post-fatigue MVC, muscle-fiber conduction velocity (MFCV) and RMS, expressed as a percentage of pre-fatigue MVC, were lower (P < 0.05) in patients (MFCV 90.3 ± 6.91%, RMS 84.50 ± 9.89%) than in controls (MFCV 100.87 ± 5.1%, RMS 92.71 ± 11.84%).


CONCLUSIONS
CMT1A patients are not only weaker than healthy individuals in the knee extensors, but they also have impaired neuromuscular recovery after fatigue.
Department of Human Movement and Sport Sciences, University of Rome Foro Italico, Piazza Lauro De Bosis 6, 00135 Rome, Italy.
Federica
F
Menotti
Ilenia
I
Bazzucchi
Francesco
F
Felici
Antonello
A
Damiani
Maria Cristina
MC
Gori
Andrea
A
Macaluso
D000328:Adult; D002607:Charcot-Marie-Tooth Disease / Q000503:physiopathology*; D004550:Elbow / Q000503:physiopathology; D004558:Electric Stimulation; D004576:Electromyography; D005260:Female; D006801:Humans; D007717:Knee / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D009119:Muscle Contraction / Q000502:physiology*; D018763:Muscle Fatigue / Q000502:physiology*; D018482:Muscle, Skeletal / Q000503:physiopathology*; D013997:Time Factors