Background: This study tried to identify the bridge exercise posture for efficient exercise application by comparing muscle activity of buttocks and thighs according to internal-external rotation and pronation & supination in bridge exercise. Method: Nine males in their 20s living in D city were randomly selected as subjects. Muscles such as vastus medialis oblique (VMO), vastus lateralis (VL), semitendinosus (ST), biceps femoris (BF), gluteus maximus (GMAX), gluteus medius (GMED), tensor fasciae latae(TFL), and adductor longus (ADL) were measured using eight channel surface electromyogram (MyoSystem 1400A, Noraxon, USA) to measure muscle activity. Statistics process was performed through paired t test. Results: In the changes in electromyogram signals according to internal-external rotations according to internal-external rotation of shinbones, in most cases muscle activity was higher in external rotation than in internal rotation, but there was no statistical significance (p>.05). In particular, it was lower in TFL and ADL. There was no statistical significance in the comparison between two groups (p>.05). In the changes in electromyogram signals according to internal-external rotations according to pronation & supination of thighs, GMED showed significantly higher value in supination than in pronation (p>.05), and in ADL pronation is significantly higher than supination (p<.05). Conclusion: In internal-external rotation of shinbone and pronation & supination of thighs in bridge exercise, changes in muscle length can make effects on muscle activity of buttocks and thighs. Therefore, muscle strength enforcement program on buttocks and thighs through bridge exercise can make effects on patients with lower limb functional damages in clinical situations.