Ankle dorsiflexor muscle size, composition and force with ageing and chronic obstructive pulmonary disease

Abstract

Loss of skeletal muscle strength is a well-recognized feature of ageing and chronic obstructive pulmonary disease (COPD). Reductions in muscle size provide only a partial explanation for this loss of strength, and additional contributory factors remain undetermined. We hypothesized that reductions in skeletal muscle strength, as measured in the ankle dorsiflexor muscles, would be reduced with ageing and COPD as a result of changes in both size and composition of the tibialis anterior muscle. Twenty healthy young subjects, 18 healthy elderly subjects and 17 patients with COPD were studied. Ankle dorsiflexor muscle strength was assessed by maximal voluntary contraction (ADMVC) and 100 Hz supramaximal electrical stimulation of the peroneal nerve (100 HzAD). Tibialis anterior cross-sectional area (TACSA) and composition, as assessed by echo intensity (TAEI), were measured using ultrasonography. Despite a lack of differences in TACSA between groups, ADMVC and 100 HzAD were significantly reduced in COPD patients compared with both healthy elderly and healthy young subjects, when expressed as absolute values and when normalized to TACSA (P < 0.01). The TAEI was, however, higher in COPD patients compared with healthy elderly (P = 0.025) and healthy young subjects (P = 0.0008), suggesting increased levels of non-contractile tissue. Across all participants, ADMVC and 100 HzAD correlated positively with TACSA (r = 0.78, P < 0.0001) and negatively with TAEI (r = -0.46, P < 0.0005). The variance in 100 HzAD was best explained with a regression model incorporating TACSA, TAEI, age and COPD status (r(2) = 0.822, P = 0.001). These data demonstrate that the loss of skeletal muscle strength in COPD is related to changes in muscle composition, with infiltration of non-contractile tissue beyond that seen during normal ageing.

Gait analysis in patients with chronic obstructive pulmonary disease: a systematic review

“…Mechanical unloading due to physical inactivity contributes to peripheral muscle abnormalities and dysfunction. Muscle weakness in COPD has been reported primarily in thigh musculature (quadriceps, in both men and women [41]), and more recently documented in the ankle dorsiflexors and plantarflexors [42,43]. Taken together, these abnormalities indicate an overall decline in both the contractile and oxidative capacity of lower limbs muscles in patients with COPD [11].…”

Nonvolitional assessment of tibialis anterior force and architecture during critical illness

“…Previous studies from this laboratory and others have demonstrated relationships between muscle size and strength in the knee extensor and ankle dorsiflexor muscles of COPD patients and age‐matched controls. Nonetheless, muscle CSA does not fully account for variation in muscle strength.…”

“…Differences in ADMF and architecture parameters between testing occasions were determined with Wilcoxon signed‐rank tests. Predicted values and cutoffs for 100‐H Z AD were determined from a regression model derived in similarly aged healthy controls: 100‐H Z AD (kg) = 4.431 + −0.116age + 0.030TA CSA − 0.389 if female. Muscle weakness in critically ill patients was defined as 1.645 residual SD below the predicted value derived from 100‐H Z AD responses from healthy individuals.…”

Incremental shuttle walk test as an indicator of decreased exercise tolerance in patients with chronic obstructive pulmonary disease

“…A frequently discussed issue is weakening of the thigh muscles, particularly changes in the vastus lateralis muscle (Seymour et al, 2010;Shrikrishna et al, 2012). Even more significant dysfunction affects the distal muscles of the lower limb, especially the tibialis anterior muscle (Gagnon et al, 2013;Maddocks, Jones, et al, 2014). It was confirmed that a loss of intramuscular fat significantly decreases exercise tolerance.…”