Influence of lifting straps on force, rate of force development and impulse outputs during isometric mid-thigh pull: Evidence from judo and resistance-trained populations

by Hung-Chih Yeh, Chia-An Ho, En-Yu Chang, Hei-Tung Lau, Chih-Wen Hsu, Hsin-Yu Tu, Pei-Hsuan Wang, Chin-Shan Ho

The isometric mid-thigh pull (IMTP) is a reliable method for assessing whole-body maximal isometric strength; however, the influence of lifting straps on IMTP performance remains unclear, particularly in sports such as judo that rely heavily on grip strength. This study recruited 30 male participants, including 15 judo athletes and 15 recreationally resistance-trained undergraduates, who completed IMTP tests under strapped and non-strapped conditions in a randomized order. Peak force (PF), rate of force development (RFD), and impulse (IP) were measured using a 1000 Hz force plate, and a two-way mixed ANOVA was used to examine the effects of group and strap condition. The results showed no significant interaction between group and condition. However, significant main effects of both group and strap condition were observed for most variables (p < 0.05), with higher PF, RFD, and IP recorded under the strapped condition. Judo athletes also demonstrated greater grip strength (51.3 ± 3.4 kg) than the resistance-trained group (44.7 ± 3.3 kg, p < 0.01). These findings suggest that the use of lifting straps enhances IMTP performance and may reduce the influence of grip strength limitations on maximal force expression. Therefore, when the purpose of IMTP testing is to assess maximal force production, the use of lifting straps may be considered to minimize the potential influence of grip-related limitations and to standardize testing procedures across athletes.