Toe Grasp Strength and Its Association with Muscle Mass and Calcaneal Bone Status in Young Adults: A Cross-Sectional Study

IntroductionSarcopenia is a progressive decline in skeletal muscle mass, strength, and physical function associated with aging [1][2][3][4][5] .It is linked to poor prognosis in various conditions, including cancer, cardiovascular disease, and osteoporotic fractures 4,[6][7][8][9][10] .Given its impact on overall health, early prevention, diagnosis, and treatment are essential.Sarcopenia is also closely associated with reduced bone mineral density (BMD) in musculoskeletal disorders 2,3 , emphasizing the interdependence between muscle and bone health.Current sarcopenia guidelines recommend diagnosing the condition based on criteria such as walking speed, hand grip strength, stand-up tests, leg circumference, and skeletal muscle mass 4,11,12 , highlighting the crucial role of lower limb muscle strength in sarcopenia assessment.Toe grasp strength (TGS), a simple and noninvasive measure of lower limb muscle function, reflects the strength of multiple toe flexor muscles in the lower leg.TGS is influenced by factors such as height, weight, sex, and age, and it is recognized as a predictor of fall risk 13,14 .Additionally, studies indicate that TGS can be improved through targeted muscle-strengthening interventions, further underscoring its importance in musculoskeletal health [13][14][15][16] .Despite these insights, the relationship between TGS, whole-body skeletal muscle mass, and bone status remains AbstractObjectives: The aim of this study was to investigate associations between toe grasp strength (TGS), skeletal muscle mass, and calcaneal bone status in young adults, and to determine whether TGS independently associates with musculoskeletal parameters.Methods: This cross-sectional study included 150 healthy young adults (118 males, 32 females; median age: 23 years).TGS was assessed using a standardized toe grasp dynamometer.Skeletal muscle mass was measured by bioelectrical impedance analysis (InBody 570), and calcaneal bone status was evaluated using quantitative ultrasound, expressed as standardized speed of sound (s-SOS).Associations between TGS, skeletal muscle index (SMI), and s-SOS were examined using correlation and multivariable regression analyses, with sex-stratified analyses.Results: Significant sex differences were observed in TGS, SMI, and s-SOS, with males showing higher values.In males, TGS was positively associated with both SMI and s-SOS.Multivariable analyses showed that higher TGS and younger age were independently associated with greater SMI and s-SOS in males.No significant associations were observed in females.Conclusions: In males, higher TGS is associated with greater skeletal muscle mass and better calcaneal bone status, suggesting that lower limb muscle strength reflects musculoskeletal status during early adulthood.Longitudinal studies are required to further clarify these associations.