Plantar flexor strength and size decrease following single‐leg disuse in uninjured adults: A meta‐analysis

• Published in: Clinical physiology and functional imaging Vol. 45; no. 1; pp. e12912 - n/a
• Main Authors: Preobrazenski, Nicholas, Seigel, Joel, Janssen, Ian, Halliday, Sandra, McGlory, Chris
• Format: Journal Article
• Language: English
• Published: England Wiley Subscription Services, Inc 01.01.2025; John Wiley and Sons Inc
• Subjects: Adult; Adults; Age; calf muscle; Computed tomography; Female; Females; Flexors; Foot; human; Humans; immobilisation; Immobilization; Impact analysis; Isometric; Leg; Locomotion; Magnetic resonance imaging; Male; Meta-analysis; muscle disuse; Muscle Strength; Muscle, Skeletal - diagnostic imaging; Muscle, Skeletal - physiology; Muscle, Skeletal - physiopathology; Physiology; Reviews; Short Communication; unloading; unweighting; Young Adult; calf muscle; computed tomography; magnetic resonance imaging; muscle disuse; immobilisation; unweighting; unloading; human
• ISSN: 1475-0961; 1475-097X; 1475-097X
• DOI: 10.1111/cpf.12912

Introduction Plantar flexors play a pivotal role in human locomotion and balance. Several original research studies and systematic reviews have characterised the impact of single‐leg disuse on plantar flexor strength and size. However, no meta‐analysis has quantified the effects of single‐leg disuse on changes in plantar flexor strength and size in uninjured adults. Aim To quantify changes in plantar flexor strength and size in response to single‐leg disuse. Methods Data were extracted from 19 studies captured in our previous systematic review on studies that employed a unilateral lower limb immobilisation model (cast or brace) and were published up to January 30, 2022. Random‐effects meta‐analyses were performed on original research studies reporting measures of plantar flexor strength (isometric, isokinetic, or repetition maximum) and size (magnetic resonance imaging or computed tomography) in uninjured adults. Results Single‐leg disuse decreased plantar flexor strength (Hedges gav = −0.71 [95% confidence interval: −0.93, −0.48], p < 0.001, 7−28 days, N = 16 studies, n = 121 participants including ≥13 females, ages 19−29) and plantar flexor size (−0.33 [−0.50, −0.15], p < 0.001, 14−35 days, N = 6, n = 49, 10 females, ages 22−27) across all durations of disuse. Discussion Single‐leg disuse decreases plantar flexor strength and size in uninjured adults. This work adds to recent meta‐analytic findings demonstrating the declines in knee extensors strength and size following single‐leg disuse. The paucity of female and participants >30 years old in the single‐leg disuse literature examining plantar flexors represents a priority of future work.