Associations Between Isometric Mid-Thigh Pull Peak Force and Functional and Cardiorespiratory Variables in Independent Older Women

Background/Objectives: Muscle strength is a key determinant of functional capacity in older adults. However, measures such as handgrip strength may not fully reflect multi-joint force production, and the relevance of the Isometric Mid-Thigh Pull (IMTP) for functional and cardiorespiratory outcomes remains unclear. This study examined the associations between IMTP-derived peak force and functional and submaximal cardiorespiratory variables in independent older women. Methods: This cross-sectional study included 21 independent older women (72.6 ± 6.9 years). Maximal isometric strength (IMTP and handgrip), functional performance (TUG, 30-CST, 30-ACT), and submaximal cardiorespiratory variables were assessed. Associations were examined using Pearson’s correlation coefficients with false discovery rate (FDR) correction (q = 5%). Results: Absolute IMTP peak force was significantly related to handgrip strength (r = 0.77; q = 0.001) and PVT1 (r = 0.67; q = 0.007). Relative IMTP peak force was related to relative handgrip strength (r = 0.71; q = 0.002), VO2VT2 (r = 0.60; q = 0.02), and inversely to COP (r = −0.56; q = 0.03). No significant relationships were observed with TUG, 30-ACT, or most cardiorespiratory variables. Conclusions: IMTP-derived peak force was related to selected neuromuscular and submaximal cardiorespiratory variables, but not to functional performance measures. These findings suggest that the IMTP may provide complementary information on neuromuscular status, although further studies are required.