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Muscle weakness, fatigue, and torque variability: Effects of age and mobility status
Author(s) -
KentBraun Jane A.,
Callahan Damien M.,
Fay Jessica L.,
Foulis Stephen A.,
Buonaccorsi John P.
Publication year - 2014
Publication title -
muscle and nerve
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.025
H-Index - 145
eISSN - 1097-4598
pISSN - 0148-639X
DOI - 10.1002/mus.23903
Subject(s) - muscle fatigue , medicine , torque , muscle weakness , physical medicine and rehabilitation , weakness , logistic regression , physical therapy , cardiology , electromyography , anatomy , physics , thermodynamics
: Whereas deficits in muscle function, particularly power production, develop in old age and are risk factors for mobility impairment, a complete understanding of muscle fatigue during dynamic contractions is lacking. We tested hypotheses related to torque‐producing capacity, fatigue resistance, and variability of torque production during repeated maximal contractions in healthy older, mobility‐impaired older, and young women. Methods : Knee extensor fatigue (decline in torque) was measured during 4 min of dynamic contractions. Torque variability was characterized using a novel 4‐component logistic regression model. Results : Young women produced more torque at baseline and during the protocol than older women ( P < 0.001). Although fatigue did not differ between groups ( P = 0.53), torque variability differed by group ( P = 0.022) and was greater in older impaired compared with young women ( P = 0.010). Conclusions : These results suggest that increased torque variability may combine with baseline muscle weakness to limit function, particularly in older adults with mobility impairments. Muscle Nerve 49 : 209–217, 2014