Relationships between objectively assessed functional mobility and handgrip strength in healthy older adults

Purpose This study aimed to characterize age-related changes in Timed Up and Go (TUG) sub-phases (i.e., sit to stand, walking and turning) quantitatively assessed using an inertial sensor in healthy older adults and to verify the degree of correlation between TUG parameters and muscular strength (assessed by handgrip strength, HGS) in the different age ranges. Methods This is a cross-sectional study performed on 125 healthy older adults aged over 65 years stratified in four groups (< 70 years, 71-75, 76-80, > 80) who underwent an instrumental TUG carried out using a wearable inertial sensor. In addition, participants were asked to carry out the HGS test to establish possible relationships between muscular strength and TUG features. Results The results show a general decline in all phases of TUG performance (albeit with some gender-related differences) which becomes significant after 75 years of age. Also, HGS was found to be systematically higher in men at any age group. Significant negative correlations between HGS and TUG phases times were found for both genders (men r = - 0.28 to - 0.50, women r = - 0.34 to - 0.60). However, when age groups were analyzed separately, such correlations are confirmed only in case of women aged < 70 years, while they vanish for most parameters in all other age groups. Conclusion The findings obtained in the present study suggest that muscular strength might have a different relationship with functional mobility according to age and gender, and this should be considered when physical activity program or rehabilitation plans are planned.