Effects of short-term strength training based on hip flexion angle-torque characteristics using a prototype machine.

[Purpose] An unexpected finding was previously observed that hip flexion torque was maximal in the deep flexion position. This study aimed to compares the short-term effects of strength training using a machine with load torque based on the hip flexion angle-torque characteristics identified in our prior study to those of an existing weight stack machine. [Participants and Methods] Seventeen participants were divided into two groups. The conventional training group (CT group) trained with a weight stack resistance machine. The non-conventional training group (non-CT group) trained with a prototype machine based on the hip flexion angle-torque characteristics identified in our previous study. Both groups trained twice weekly for four weeks. Maximum isometric hip flexion torque at 0°, 30°, 60°, 90°, and 105° was measured before and after training, and compared between the groups. [Results] Maximum isometric hip flexion torque showed an interaction between training type and training duration only at 105° of hip flexion, with significantly higher torque observed in the non-CT group. [Conclusion] Short-term training based on the hip flexion angle-torque characteristics identified in our prior study was effective in significantly strengthened muscles in the deep hip flexion range.