Quadriceps Fatigability after Single Muscle Exercise in Patients with Chronic Obstructive Pulmonary Disease

Abstract

The purpose of this study was to compare quadriceps fatigability in patients with varying severity of chronic obstructive pulmonary disease with age-matched control subjects. Ten healthy control subjects, 8 patients with severe disease (FEV1 less than 35% predicted), and 11 patients with mild to moderate disease were studied. The FEV1 was 1.75 +/- 0.13 L (SE), 50.4 +/- 2.9% of predicted in the mild to moderate group, and 0.87 +/- 0.06 L, 25.9 +/- 1.9% of predicted in the severe group. Quadriceps fatigue was quantified by the reduction in potentiated twitch force after a potentially fatiguing task. All subjects performed three sets of 10 maximum voluntary contractions of the right quadriceps muscle. Quadriceps maximum voluntary contraction force was 58.3 +/- 3.3 kg for the healthy older group, 49.0 +/- 4.2 kg in the mild to moderate group, and 44.3 +/- 4.7 kg in the severe group. The fall in potentiated twitch force after exercise was significantly greater in the patients with severe disease than in the healthy control subjects. In conclusion, the quadriceps in patients with severe chronic obstructive pulmonary disease are more fatigable than those in age- and sex-matched healthy control subjects.

Upper and Lower Limb Muscles in Patients With COPD: Similarities in Muscle Efficiency But Differences in Fatigue Resistance

“…15 Unlike those observed in the lower limb muscles, alterations in fiber-type distribution and decreased metabolic capacity do not seem to be involved in early fatigue of the upper limb muscles. This assertion is based on previous studies that demonstrated preserved or even increased oxidative capacity, 7 as well as a concomitant presence of the normal, atrophic, and hypertrophic pattern of fibers within the middle deltoid, when compared to a control group. 15 Although widely used for evaluation of muscle fatigue, submaximal sustained isometric contraction [40][41][42][43][44] has the disadvantage of being dependent on motivation.…”

“…These changes increase the fatigability of the quadriceps femoris, which has been demonstrated in both dynamic 5,6 and isometric contractions. 7 For the upper limbs a variety of muscles have been studied, making it difficult to generalize upper limb performance results. 2,8 Because of the finding that the isometric handgrip force is conserved in patients with COPD, some studies infer that the upper limb function is preserved.…”

Skeletal Muscle Dysfunction in Patients with Chronic Obstructive Pulmonary Disease

“…As such, they suggest that factors other than atrophy might play a role in explaining skeletal muscle dysfunction in COPD patients (Malaguti et al 2006). Their position is supported by several reports that have documented the presence of intrinsic abnormalities inside limb muscle fi bers of COPD patients, especially in the form of contractile fatigue (Mador et al 2000(Mador et al , 2001(Mador et al , 2003a(Mador et al , 2003bSaey et al 2003Saey et al , 2005Saey et al , 2006. A good example of these reports is that of Mador and colleagues (Jeffery et al 2000) who found a signifi cant decrease in quadriceps twitch force of patients with severe COPD -by more than 20% within 30min of termination of exercise -a value that was signifi cantly greater than that observed in control subjects.…”

The Effect of a Short Duration, High Intensity Exercise Intervention on Gait Biomechanics in Patients With COPD: Findings From a Pilot Study

“…A primary factor leading to muscular fatigue could be related to abnormal skeletal muscle structureandfunction,which,inCOPD,includesabnormal cellmassalterations,muscularproteindegradationleading tomusclewasting/atrophy,impairedenergyproduction andmetabolicperformance,andincreasedsusceptibility tomusclefatigueandweakness. [12][13][14][15][16][17][18][19][20] GaitalterationsinpatientswithCOPDarelikelysecondarytoalteredskeletal musclestructureandfunction.Mechanismsleadingto alteredskeletalmusclestructureandfunctioninCOPD are uncertain and are not clearly delineated. Disuse and/or systemic inflammation are believed to play a role.…”