Background: Muscle activities of gluteus maximus (GM) and hamstring (HAM) have important roles in the stability and mobility of the hip joint during various functional activities including bridge and prone hip extension exercises. Objects: The purpose of this study is to investigate muscle activities of GM, multifidus (MF) and HAM during three different bridge exercises in healthy individuals. Methods: Twenty healthy subjects were participated. Electromyography device was used to measure muscle activities of GM, MF and HAM. Each subject was asked to perform three different bridge exercises with hip abduction (0°, 15°, 30°) in random order. One-way repeated measures analysis of the variance and a Bonferroni post hoc test were used. Statistical significance was set at α = 0.01. Results: The muscle activity of GM was significantly different among three conditions (hip abduction 0°, 15°, 30°) (adjusted p-value [Padj] < 0.01). The muscle activity of GM was significantly greater during bridge exercise with hip abduction 30° compared to 0° and 15° (Padj < 0.01). There was no significant difference in the muscle activity of MF and HAM muscle (Padj > 0.01). The ratio of muscle activity (ratio = GM/HAM) during bridge exercise with hip abduction 30° was significant greater compared to the hip abduction angles 0° and 15° (Padj < 0.01). Conclusion: Bridge exercise with hip abduction 30° can be recommended to selectively facilitate the muscle activity of GM and improve the ratio of muscle activity between GM and HAM.

Background: Stroke patients have weak trunk muscle strength due to brain injury, so a single type of exercise is advised for restoring functionality. However, even after intervention, the problem still lies and it is suggested that another intervention method should be applied with exercise in order to deal with such problem. Objectives: To Investigate the effect of bridge exercise combined with functional electrical stimulation (FES) on trunk muscle activity and balance in stroke patients. Design: Randomized controlled trial. Methods: From July to August 2020, twenty stroke patients was sampled, ten patients who mediated bridge exercises combined with functional electrical stimulation were assigned to experiment group I, and ten patients who mediated general bridge exercises were assigned to experiment groupⅡ. For the pre-test, using surface EMG were measured paralyzed rectus abdominis, erector spinae, transverse abdominis/internal oblique muscle activity, and using trunk impairment scale were measured balance. In order to find out immediate effect after intervention, post-test was measured immediately same way pre-test. Results: Change in balance didn’t show significant difference within and between groups, but muscle activity of trunk was significant difference rectus abdominis and erector spinae within groups I (P<.01), also between groups was significant difference (P<.05). Conclusion: Bridge exercise combined with FES could improve trunk function more effectively than general bridge exercise due to physiological effect of functional electrical stimulation.

Background: The bridge exercise targets the gluteus maximus (Gmax) and gluteus medius (Gmed). However, there is also a risk of dominant hamstring (HAM) and erector spinae (ES) muscles. Objects: To analyze the muscle activity the of Gmax, Gmed, HAM and ES during the bridge exercise with and without hip external rotation in different degrees of knee flexion. Methods: Twenty-three subjects were participated. The electormyography (EMG) activity of the Gmax, Gmed, HAM and ES muscles was recorded during the exercise. The subjects performed the bridge exercise under four different conditions: (a) with 90˚ knee flexion, without hip external rotation (b) with 90˚ knee flexion, with hip external rotation (c) with 135˚ knee flexion, without hip external rotation (d) with 135˚ knee flexion, with hip external rotation. Results: There was no significant interaction effect between the degree of knee flexion and hip external rotation. There was a significant main effect for degree of knee flexion in Gmax, HAM muscles activity. Gmax muscle activity was significantly greater in the 135˚ knee flexion position than in the 90˚ knee flexion position (p<.001). While HAM muscle activity was significantly less in 135˚ knee flexion position than in the 90˚ knee flexion position (p<.001). ES muscle activity was significantly less in the 135˚ knee flexion position than in the 90˚ knee flexion position (p=.002). The activity of both the Gmax and Gmed muscles was significantly greater with hip external rotation (p<.001 and p=.005, respectively). Conclusion: For patients performing the bridge exercise, positioning the knee in 135° of flexion with hip external rotation is effective for improving Gmax and Gmed muscle activity while decreasing HAM, and ES muscle activity.