Sex Differences In Mid-thigh Isometric Pull Performance Comparing Traditional Bar Grip And Pelvic Belt Methods

The isometric mid-thigh pull (IMTP) test is an effective and reliable method to measure strength performance in various populations. Using portable force plates, previous research had compared a bar grip (Bar) to a pelvic belt (Pel) method of the IMTP test and demonstrated good test-retest reliability. However, there is a limited data on sex differences on IMTP performance using both methods. PURPOSE: To compare sex differences while using the Bar and Pel methods on force generation from IMTP performance. METHODS: Twenty participants, ten males age (19.9 ± 1.2 y); body weight (72.90 ± 8.24 kg); height (1.77 ± 0.06 m); BMI (23.14 ± 2.05 kg·m-2) and ten females (20.1 ± 1.5 y); body weight (60.54 ± 8.45 kg); height (1.62 ± 0.06 m); BMI (22.99 ± 3.36 kg·m-2) volunteered to participate in this study. IMTP testing data included peak force and relative peak force. RESULTS: Peak force (N) and relative peak force (N·kg-1) were significantly (p< 0.05) lower in women compared to men. Further, Pel Peak force (N) and relative peak force (N·kg-1) were significantly (p< 0.05) greater compared to Bar in men but not in women. Lastly, there was a significant (p< 0.05) interaction between the groups in peak force (N) and relative peak force (N·kg-1). CONCLUSIONS: The results of this study indicated that the Pel method compared to the Bar method to perform the IMTP test yielded higher absolute, relative peak force and peak force relative to body weight values in men but not in women. Further, although some studies demonstrated that the upper body is disproportionally weaker in women, this was not evident in the current study. Regardless of the relative involvement of the lower and the upper body in each of the methods (Pel versus Bar), only men demonstrated strength differences between the methods.