TY - JOUR
T1 - Aging and skeletal muscle force control
T2 - Current perspectives and future directions
AU - Pethick, Jamie
AU - Taylor, Matthew J.D.
AU - Harridge, Stephen D.R.
N1 - Publisher Copyright:
© 2022 The Authors. Scandinavian Journal of Medicine & Science In Sports published by John Wiley & Sons Ltd.
PY - 2022/10
Y1 - 2022/10
N2 - During voluntary muscle contractions, force output is characterized by constant inherent fluctuations, which can be quantified either according to their magnitude or temporal structure, that is, complexity. The presence of such fluctuations when targeting a set force indicates that control of force is not perfectly accurate, which can have significant implications for task performance. Compared to young adults, older adults demonstrate a greater magnitude and lower complexity in force fluctuations, indicative of decreased steadiness, and adaptability of force output, respectively. The nature of this loss-of-force control depends not only on the age of the individual but also on the muscle group performing the task, the intensity and type of contraction and whether the task is performed with additional cognitive load. Importantly, this age-associated loss-of-force control is correlated with decreased performance in a range of activities of daily living and is speculated to be of greater importance for functional capacity than age-associated decreases in maximal strength. Fortunately, there is evidence that acute physical activity interventions can reverse the loss-of-force control in older individuals, though whether this translates to improved functional performance and whether lifelong physical activity can protect against the changes have yet to be established. A number of mechanisms, related to both motor unit properties and the behavior of motor unit populations, have been proposed for the age-associated changes in force fluctuations. It is likely, though, that age-associated changes in force control are related to increased common fluctuations in the discharge times of motor units.
AB - During voluntary muscle contractions, force output is characterized by constant inherent fluctuations, which can be quantified either according to their magnitude or temporal structure, that is, complexity. The presence of such fluctuations when targeting a set force indicates that control of force is not perfectly accurate, which can have significant implications for task performance. Compared to young adults, older adults demonstrate a greater magnitude and lower complexity in force fluctuations, indicative of decreased steadiness, and adaptability of force output, respectively. The nature of this loss-of-force control depends not only on the age of the individual but also on the muscle group performing the task, the intensity and type of contraction and whether the task is performed with additional cognitive load. Importantly, this age-associated loss-of-force control is correlated with decreased performance in a range of activities of daily living and is speculated to be of greater importance for functional capacity than age-associated decreases in maximal strength. Fortunately, there is evidence that acute physical activity interventions can reverse the loss-of-force control in older individuals, though whether this translates to improved functional performance and whether lifelong physical activity can protect against the changes have yet to be established. A number of mechanisms, related to both motor unit properties and the behavior of motor unit populations, have been proposed for the age-associated changes in force fluctuations. It is likely, though, that age-associated changes in force control are related to increased common fluctuations in the discharge times of motor units.
KW - aging
KW - complexity
KW - force control
KW - force steadiness
KW - motor unit
KW - muscle
KW - physical activity
UR - http://www.scopus.com/inward/record.url?scp=85135091425&partnerID=8YFLogxK
U2 - 10.1111/sms.14207
DO - 10.1111/sms.14207
M3 - Review article
AN - SCOPUS:85135091425
SN - 0905-7188
VL - 32
SP - 1430
EP - 1443
JO - Scandinavian Journal of Medicine and Science in Sports
JF - Scandinavian Journal of Medicine and Science in Sports
IS - 10
ER -