Effects of Age on Strength and Morphology of Toe Flexor Muscles

Abstract

Study Design Descriptive, cross-sectional. Background Age-related muscle atrophy is common in lower-limb muscles. We therefore speculated that foot muscles may also diminish with age. However, there is a paucity of literature characterizing foot muscle strength and morphology, and any relationship between these 2, in older people. Objective To compare the strength and size of the toe flexor muscles of older adults relative to their younger counterparts. Methods Seventeen young adults with a normal foot type were matched by sex and body mass index to 17 older adults with a normal foot type, from an available sample of 41 younger (18 to 50 years of age) and 44 older (60 or more years of age) adults. Among the matched groups (n = 34), muscle thickness and cross-sectional area for 5 intrinsic and 2 extrinsic toe flexor muscles were obtained using ultrasound. Toe strength was assessed using a pressure platform. Differences in toe flexor strength and muscle size between the young and older matched groups were determined using analysis of covariance (controlling for height). Correlations between strength and size of the toe flexor muscles of the pooled group (n = 34) were also calculated. Results Toe strength and the thickness and cross-sectional area of most foot muscles were significantly reduced in the older adults (P<.05). Hallux and toe flexor strength values were strongly correlated with the size of the intrinsic toe flexor muscles. Conclusion The smaller foot muscles appear to be affected by sarcopenia in older adults. This could contribute to reduced toe flexion force production and may affect the ability of older people to walk safely. Interventions aimed at reversing foot muscle atrophy in older people require further investigation. J Orthop Sports Phys Ther 2016;46(12):1065-1070. Epub 29 Oct 2016. doi:10.2519/jospt.2016.6597.

Intrinsic foot muscle size can be measured reliably in weight bearing using ultrasound imaging

“…10% and 90% body weight, bilateral standing, seated/non-weight bearing). In our study, age was not related to either FIS or ABH morphology which supports previous reports in healthy adults that include broader age ranges beyond 65 years [20,29]. We found that when controlling for body size and foot posture, FIS thickness, but not ABH, was greater in males compared with females.…”

Differences in foot muscle morphology and foot kinematics between symptomatic and asymptomatic pronated feet

“…In our previous study, we found larger cross‐sectional area (CSA) and thickness of foot muscles in asymptomatic pronators compared to their counterparts with a neutral foot posture . As a larger muscle is related to higher strength capacity, this seems to suggest a compensatory mechanism in asymptomatic pronators. However, this finding cannot be extrapolated to a potential association between symptomatic pronators and weakness or dysfunction of foot muscles, as the comparison was made between asymptomatic pronators and neutral foot controls.…”

Effects of Long-Term Use of Insoles with a Toe-Grip Bar on the Balance, Walking, and Running of Preschool Children: A Randomized Controlled Trial

“…Movable toes play an important role in posture control, walking, and running [1,2]. Previous studies have shown that toe-grip force, the so-called toe-grip strength or toe flexor strength, decreases with age [3][4][5][6] and that decreased toe-grip strength is associated with problems with balance and walking ability and the occurrence of falls in the elderly [7][8][9][10][11]. Decreased toe-grip strength has also been observed in children and is particularly related to floating toes and flat feet [12,13].…”