2021 Volume 24 Issue 1 Pages 33-37
Joint angle specificity in strength training, which means that muscle strength improves only around the joint angle where training is performed has conventionally been reported. However, this concept has only been verified in high-load training. We examined whether the joint angle specificity is also valid under low-load training. As a result, we found that muscle strength gains did not follow the joint angle specificity in ankle isometric training, ankle isotonic training, and hip isometric training. On the other hand, the muscle fascicle length measured by the ultrasound was shown to be consistent between the training conditions and the conditions in which muscle strength was improved, suggesting that muscle strength gains were specific to the fascicle length. This hypothesis is a new concept that has never been proposed before, and we reported it as the specificity of fascicle length in strength training.
