Abstract
The purpose of this study was to investigate the electromyographic (EMG) activities of the multifidus, longissimus, and iliocostal muscles in the standing and forefoot standing positions in order to understand the relationship between each muscle activity and thoracolumbar extension in the forefoot standing position. This study recruited 10 healthy male volunteers (mean age: 28.4 ± 6.1 years). The EMG activities of the multifidus, longissimus, and iliocostal muscles were measured in the standing and forefoot standing positions. The values of the integrated EMG activities of each task were compared. Each muscle showed a significant increase in the value of the integrated EMG activities in the forefoot standing position (p<0.01). The activities of the iliocostal muscles were separated into two types: Group A, in which the EMG activities did not increase much, and Group B, in which the EMG activities clearly increased. In group A, the forefoot standing position involved extension of the hip joint, and lumbar alignment was almost identical to that in the standing position. In group B, lumbar lordosis and anteversion of the pelvis were significantly greater in the forefoot standing position than in the standing position.
