Type II muscle fibre properties are not associated with balance recovery following large perturbations during walking in young and older adults

Abstract

Falls among older adults are often attributed to declining muscle strength with ageing. Associations between muscle strength and balance control have been reported, but the evidence for, and key mechanisms of resistance exercise in fall prevention are unclear. No studies have directly examined the relationship between muscle fibre characteristics and reactive balance control. Here, we address whether or not Type II muscle fibre characteristics associate with reactive balance during walking in young and older adults with varying muscle fibre type composition. We analyse muscle biopsy-derived fibre characteristics and stability during a treadmill-based walking perturbation (trip-like) task of healthy young adults, healthy, normally active older adults, trained older adults and physically impaired older adults. We find no significant associations between Type II muscle fibre properties and reactive balance during walking, indicating that practitioners and researchers should consider more than just the muscle tissue properties when assessing and intervening on fall risk.

A physiological comparison of the new—over 70 years of age—marathon record holder and his predecessor: A case report

“…Because the current athlete exhibited >90% type I fibers in the vastus lateralis, this fiber distribution may have contributed to his excellent running economy. Indeed, this percentage of type I fibers is substantially higher than the average type I fiber percentage for older adults (e.g., 68% for master cyclists ( Pollock et al, 2018 ) or 41%–45% for sedentary older men ( Houmard et al, 1998 ; McCrum et al, 2021 )). Note however that some studies also observed poorer running economy with higher type I fiber percentages at relatively slow running speeds (e.g., 10–11 km h −1 ) ( Hunter et al, 2015 ), thus questioning the overall relevance of fiber type to running economy.…”

“…Two years before the experiments in the current study, the athlete had a muscle biopsy taken from the vastus lateralis as part of other studies registered at clinicaltrials.gov with identifier NCT03666013. Here, we report the athlete's muscle fiber composition and mitochondrial capacity as previously determined in these studies (Grevendonk et al, 2021;McCrum et al, 2021). Briefly, muscle fiber content was determined using histochemical analysis as described previously (McCrum et al, 2021).…”

“…Here, we report the athlete's muscle fiber composition and mitochondrial capacity as previously determined in these studies (Grevendonk et al, 2021;McCrum et al, 2021). Briefly, muscle fiber content was determined using histochemical analysis as described previously (McCrum et al, 2021). Mitochondrial capacity was assessed ex vivo using highresolution respirometry assessed with an Oxygraph (Grevendonk et al, 2021).…”

“…Such information may provide valuable insights to individuals seeking to optimize performance in aging athletes. Finally, we also explore potential mechanistic reasons for superior performance using a muscle biopsy collected from the athlete as part of previous studies ( Grevendonk et al, 2021 ; McCrum et al, 2021 ). This technique made it possible to assess fiber type distribution, and ex vivo mitochondrial respiration capacity, and mitochondrial content.…”

Age and cognitive load affect muscle activation profiles in response to physical perturbations while walking

“…It is suggested that changes in muscle architecture cause changes in muscle activation patterns. This led McCrum et al [26] to investigate the association between type II muscle fiber properties and balance recovery following large perturbations during walking in young and older adults. They found no association.…”