The effect of the trunk and gluteus maximus muscle activities according to support surface and hip joint rotation during bridge exercise.

[Purpose] The purposes of this study were to strengthen gluteus maximus and trunk muscles depending upon the hip joint direction by bridging exercise on an unstable and stable surface, and to suggest an intervention method for efficient and selective exercise. [Participants and Methods] The test measured the muscle activities with the external rotation and internal rotation of 25 degrees and hip joint neutral position of 0 degree on a stable and unstable surface each exercise 3 times for 9 seconds. [Results] External oblique abdominis showed a higher muscle activity on the unstable surface and internal rotation. Erector spinae showed no significant difference on the surfaces and demonstrated the highest muscle activity at the internal rotation. Gluteus maximus showed a higher muscle activity on the stable surface and external rotation and the interaction effect between the surface and the angle indicated a statistical significance as well. [Conclusion] Muscle activities appear different depending upon the change of surface and joint angle, and it can be said that the correct mobilization of muscle fiber relying on the muscle arrangement direction and muscle contraction direction is the most important factor for gluteus maximus.

The effect of modified cervical exercise on smartphone users with forward head posture.

[Purpose] The purpose of this study was to evaluate the effect of modified cervical exercise and determine whether such exercise improves the range of motion of the cervical movement in smartphone users with forward head posture. [Subjects and Methods] Some 32 subjects with forward head posture participated in this study. They were randomly allocated to three groups, and the modified cervical exercises were performed either once, twice, or three times per day. The exercise program was followed for four weeks and then the joint range of motion of the participants was measured. [Results] A significantly increased range of motion was seen in all three groups that performed the modified cervical exercises. The analysis of the effects among the three groups indicated that the greatest effect was seen in Group C, members of which performed the modified exercises three times per day. In addition, a significant difference was found between Group A and Group C in terms of the inter-group results. [Conclusion] According to the results of this study, although the modified cervical exercises were performed for only a relatively short duration (four weeks), the exercises brought about an improvement in the forward head posture that was induced by using a smartphone.

Change in trunk muscle activities with prone bridge exercise in patients with chronic low back pain.

[Purpose] The aim of this study was to determine the effect of three different bridge exercises on internal oblique, external oblique, transverse abdominis, and erector spinae activities. [Subjects and Methods] Forty-five subjects with chronic low back pain participated in this study. The training outcome was evaluated with three different testing methods: supine bridge exercise, supine bridge on Swiss ball exercise, and prone bridge exercise. The activities of the transverse abdominis, internal oblique, external oblique, and erector spinae were measured using surface electromyography. [Results] There were significant differences in the internal oblique, external oblique, and erector spinae according to the three kinds of bridging exercises. The internal oblique, external oblique and transverse abdominis activities were highest in the prone bridge exercise, followed by those in the supine bridge on Swiss ball exercise, and supine bridge exercises. The activity of erector spine was highest in the supine bridge on Swiss ball exercise followed by the supine bridge exercise and prone bridge exercise. [Conclusion] These results suggest that prone bridge exercise is more effective than conventional supine bridge exercise and supine bridge on Swiss ball in increasing trunk muscle activity of chronic low back pain patients.

Differences in onset time between the vastus medialis and lateralis during stair stepping in individuals with genu varum or valgum.

[Purpose] We investigated the difference in onset time between the vastus medialis and lateralis according to knee alignment during stair ascent and descent to examine the effects of knee alignment on the quadriceps during stair stepping. [Subjects] Fifty-two adults (20 with genu varum, 12 with genu valgum, and 20 controls) were enrolled. Subjects with > 4 cm between the medial epicondyles of the knees were placed in the genu varum group, whereas subjects with > 4 cm between the medial malleolus of the ankle were placed in the genu valgum group. [Methods] Surface electromyography was used to measure the onset times of the vastus medialis and vastus lateralis during stair ascent and descent. [Results] The vastus lateralis showed more delayed firing than the vastus medialis in the genu varum group, whereas vastus medialis firing was more delayed than vastus lateralis firing in the genu valgum group. Significant differences in onset time were detected between stair ascent and descent in the genu varum and valgum groups. [Conclusion] Genu varum and valgum affect quadriceps firing during stair stepping. Therefore, selective rehabilitation training of the quadriceps femoris should be considered to prevent pain or knee malalignment deformities.

The effects of prone bridge exercise on the Oswestry disability index and proprioception of patients with chronic low back pain.

[Purpose] The purpose of this study was to investigate the effect of bridge exercises on the Oswestry disability index (ODI) scores and proprioception among patients with chronic low back pain (CLBP). [Subjects and Methods] A total of 38 patients participated in this study. After eight weeks of bridge exercise, the joint position angle of the body trunk was measured and the ODI was used in survey form to investigate the intensity of the patients' low back pain. [Results] After eight weeks of exercise, the ODI showed significant differences in all three groups. Subjects' joint position sense of the trunk in both lumbar flexion and extension was also significantly different after completing the exercise program; this was true for all three groups. [Conclusion] Performing the prone bridge exercise for eight weeks improved proprioceptive function and reduced pain and impediment of activity, showing it a more effective exercise than other bridge exercises.

The effects of prone bridge exercise on trunk muscle thickness in chronic low back pain patients.

[Purpose] This study aimed to investigate the effects of prone bridge exercise on trunk muscle thickness. [Subjects and Methods] Thirty-seven chronic low back pain patients participated in this study. Each participant was randomly assigned to one of three exercise groups, namely, a prone bridge exercise group, supine bridge exercise on a Swiss ball group, and supine bridge exercise group. The thicknesses of the transverse abdominis (TrA), internal oblique (IO), and external oblique (EO) were measured using ultrasound. [Results] After eight weeks of training, the three groups showed significant increases in the thicknesses of the TrA, IO, and EO. Among the groups, TrA and IO showed significantly different muscle thicknesses. [Conclusion] The prone bridge exercise significantly affected the thicknesses of the TrA, IO, and EO unlike the supine bridge exercises. Based on the results of this study, the prone bridge exercise is a more effective method to improve trunk stability than conventional supine bridge exercises.

Differences in onset timing between the vastus medialis and lateralis during concentric knee contraction in individuals with genu varum or valgum.

[Purpose] The purpose of this study was to investigate the difference in onset timing between the vastus medialis and lateralis among the different knee alignments, as well as the best isokinetic angular velocity for an isokinetic concentric contraction. [Subjects] Fifty-two adults (20 with genu varum, 12 genu valgum, and 20 controls) were enrolled in this study. Subjects with > 4 cm between the medial epicondyles of the knee were placed in the genu varum group, whereas subjects with > 4 cm between the medial malleolus of the ankle were placed in the genu valgum group. [Methods] Surface electromyography was used to measure the onset times of the vastus medialis and vastus lateralis during concentric contractions at 30, 60, and 90°/sec. [Results] The vastus lateralis showed more delayed firing than the vastus medialis in the genu varum group, whereas vastus medialis firing was delayed more than that of the vastus lateralis in the genu valgum group. No differences in onset timing were observed between the vastus medialis and lateralis according the different angular velocities during concentric contractions in all three groups. [Conclusion] Genu varum and valgum affect quadriceps firing. Therefore, selective rehabilitation training of the quadriceps femoris should be considered to prevent pain or knee malalignment deformities.

Changes in the activities of the trunk muscles in different kinds of bridging exercises.

[Purpose] The purpose of this study was to examine the effects of different types of bridging exercises on the activities of the trunk muscles. [Methods] Twenty-four students participated in this experiment. The activities of the internal oblique (IO), external oblique (EO), rectus abdominis (RA), and erector spinae (ES) muscles were measured in four different bridging exercises. [Results] There were significant differences in the IO, EO, RA, and ES among the four kinds of bridging exercise. The activities of IO, EO and RA were the highest in prone bridging (exercise 4), followed by unilateral bridging (exercise 3), and supine bridging on balance pads (exercise 2). In conventional bridging (exercise 1), the activities of IO, EO, and RA were the lowest. The activity of ES was the highest in exercise 3 followed by exercises 2 and 1. The activity of ES was the lowest than in exercise 1. [Conclusions] Bridging exercise in the prone position may be a more effective method of enhancing trunk muscle activities exercises in other positions.