Eun-Kyung Koh

A comparison in the muscle activity of the abductor hallucis and the medial longitudinal arch angle during toe curl and short foot exercises

OBJECTIVE To compare the muscle activity of the abductor hallucis (AbdH) and the medial longitudinal arch (MLA) angle during toe curl (TC) and short foot (SF) exercises while sitting or in one-leg standing position. DESIGN Two-way repeated-measures ANOVA was used to analyze the effects of exercise type and position on the muscle activity of the AbdH and the MLA angle. PARTICIPANTS Twenty subjects with normal feet participated in this study. MAIN OUTCOME MEASURES The muscle activity of the AbdH and the MLA angle were measured during TC and SF exercises while sitting or in one-leg standing position. RESULTS The EMG activity of AbdH in SF exercise was significantly greater than during TC exercise in both exercise postural positions (p < 0.001). During the SF exercise, the EMG activity of the AbdH in the one-leg standing position was significantly higher than that while sitting (p < 0.001). The MLA angle in SF exercise was significantly smaller than during TC exercise in both postural positions (p < 0.001). CONCLUSIONS These results suggest that SF exercise is a more useful strengthening exercise than TC exercise in activating the AbdH muscle.

Effect of foot orthoses and short-foot exercise on the cross-sectional area of the abductor hallucis muscle in subjects with pes planus: A randomized controlled trial1

OBJECTIVE To prevent overuse injuries related to excessively pronated feet, the strengthening of the foot intrinsic muscles has been recommended. The purpose of this study was to examine the effects of foot orthoses and a short-foot exercise intervention on the cross-sectional area (CSA) of the abductor hallucis (AbdH) muscle and strength of the flexor hallucis (FH) in subjects with pes planus. METHODS Twenty-eight subjects with pes planus were randomly assigned to the foot orthosis (FO) group or the combined foot orthosis and short-foot exercise (FOSF) group for an 8-week intervention. The CSA of the AbdH muscle and the strength of FH were assessed before and after intervention. Data were analyzed using a mixed-model ANOVA. RESULTS Significant group by intervention interaction effects were observed in CSA of the AbdH (p=0.009) and strength of the FH (p=0.015). The results of the post hoc paired t-test showed that that the CSA of the AbdH muscle and the strength of the FH significantly increased after the intervention in both groups (p=0.000). The mean CSA of the AbdH muscle and the strength of FH were significantly greater in subjects in the FOSF group compared with subjects in the FO group (mean difference of FO vs. FOSF=13.61 mm(2) in CSA of AbdH muscle; 0.90 kgf in strength of FH; p=0.008). CONCLUSIONS Results from this study demonstrate that foot orthoses combined with short-foot exercise is more effective in increasing the CSA of the AbdH muscle and the strength of FH compared with foot orthoses alone. Therefore, foot orthoses combined with short-foot exercise are recommended for improving strength of AbdH muscle in subjects with pes planus.

Effect of medial arch support on displacement of the myotendinous junction of the gastrocnemius during standing wall stretching.

STUDY DESIGN Controlled laboratory study. OBJECTIVES To examine the effects of standing wall stretching with and without medial arch support (WMAS versus WOMAS) on the displacement of the myotendinous junction (DMTJ) of the medial gastrocnemius, rearfoot angle, and navicular height in subjects with neutral foot alignment and pes planus. BACKGROUND Standing wall stretching is often prescribed to increase ankle dorsiflexion range of motion for sports fitness and rehabilitation. However, the effect of standing wall stretching WMAS on DMTJ is unknown. METHODS Fifteen subjects with neutral foot alignment and 15 subjects with pes planus performed standing wall stretching under WMAS and WOMAS conditions. Measurements of DMTJ and rearfoot position were performed using ultrasonography and video imaging. Navicular height was measured using a ruler. Dependent variables were examined with a 2-way mixed-design analysis of variance. The 2 factors were foot type (neutral foot versus pes planus) and stretching condition (WMAS versus WOMAS). RESULTS There were significant interactions of medial arch support by foot type for DMTJ, rearfoot angle, and navicular drop (P<.001). A post hoc paired t test showed that standing wall stretching in the WMAS condition significantly increased the DMTJ, compared to stretching in the WOMAS condition, in subjects with neutral foot (mean +/- SD, 9.6 +/- 1.6 versus 10.5 +/- 1.6 mm; difference, 0.9 mm; 99% CI: 0.4-1.4 mm) and in those with pes planus (10.0 +/- 1.8 versus 12.7 +/- 2.0 mm; difference, 2.7 mm; 99% CI: 1.9-3.5 mm) (P<.001). When comparing WOMAS and WMAS, the difference in DMTJ (1.8 mm; 99% CI: 0.9-2.7 mm) was significantly greater in subjects with pes planus than in those with neutral foot (P<.001). CONCLUSION Standing wall stretching with medial arch support maintained subtalar joint neutral position and increased the length of the gastrocnemius in subjects with pes planus. When prescribing standing wall stretching, clinicians need to emphasize the use of medial arch support to effectively stretch the gastrocnemius in subjects with pes planus.

Effect of Head Posture and Breathing Pattern on Muscle Activities of Sternocleidomastoid and Scalene during Inspiratory Respiration

The purpose of this study was to determine the effect of head posture and respiratory pattern on muscle activities of ster- nocleidomastoid (SCM) and scalene during maximal respiration. The seventeen subjects with upper-costal breathing pattern were participated in this study. Surface electromyography was used to measure the muscles activities of SCM and scalene. The volume and velocity of inspiration were monitored by using the spirometer in each subject. Each subject was performed the 3-cycle of respiration in each condition. The mean values of three peak muscle activity in each muscle were used in the data analysis. A2 (head posture: forward head posture: FHP vs. neutral posture) X 2 (breathing pattern: costal vs. diaphragmatic) repeated-measures analysis of variance (ANOVA) was used to compare the normalized muscle activities of the SCM and scalene. The results showed that the muscle activities of SCM and scalene in diaphragmatic breathing were significantly lower than those in costal breathing for each head posture (p<.0125). The muscle activities of SCM in neutral position were lower than those in forward head position during costal breathing (p<.0125). The diaphragmatic breathing in neutral position of head is recommended to decrease the tension of the accessory inspiratory muscles during respiration in neck-pain patients with FHP.

Effect of feedback techniques for lower back pain on gluteus maximus and oblique abdominal muscle activity and angle of pelvic rotation during the clam exercise

OBJECTIVES This study was conducted in order to determine the effect of feedback tools on activities of the gluteus maximus (Gmax) and oblique abdominal muscles and the angle of pelvic rotation during clam exercise (CE). DESIGN Comparative study using repeated measures. SETTING University laboratory. PARTICIPANTS Sixteen subjects with lower back pain. MAIN OUTCOME MEASURES Each subject performed the CE without feedback, the CE using a pressure biofeedback unit (CE-PBU), and the CE with palpation and visual feedback (CE-PVF). Electromyographic (EMG) activity and the angles of pelvic rotation were measured using surface EMG and a three-dimensional motion-analysis system, respectively. One-way repeated-measures ANOVA followed by the Bonferroni post hoc test were used to compare the EMG activity in each muscle as well as the angle of pelvic rotation during the CE, CE-PBU, and CE-PVF. RESULTS The results of post-hoc testing showed a significantly reduced angle of pelvic rotation and significantly more Gmax EMG activity during the CE-PVF compared with during the CE and CE-PBU. CONCLUSION These findings suggest that palpation and visual feedback is effective for activating the Gmax and controlling pelvic rotation during the CE in subjects with lower back pain.

The Comparison of Electromyographic Ratio of Serratus Anterior and Upper Trapezius According to Exercise Position and Shoulder Flexion Angle during Scapular Protraction Exercises

The purpose of this study was to investigate the activities of the serratus anterior (SA) and upper trapezius (UT) muscles during scapular protraction exercise with a dumbbell. Twenty-one healthy subjects with no medial history of shoulder pain or upper extremity disorders were recruited for this study. Subjects performed scapular protraction at 90° and 130° shoulder flexion with a dumbbell in supine and standing positions. The activities of the SA and UT were measured via surface electromyography (EMG) during 4 scapular protraction exercises. A 2 (angle) × 2 (position) repeated-measures analysis of variance (ANOVA) was used to compare the normalized activities of the SA and UT and the UT/SA ratio. The results showed that activities of both the SA and UT were the highest for the scapular protraction exercise at 130° shoulder flexion in the standing position. However, the UT/SA ratio was the lowest for the exercise at 90° shoulder flexion in supine position. Therefore, for selective activation of the SA muscle, we recommend performing the scapular protraction exercise with a dumbbell in the supine position at 90° shoulder flexion.

Comparison of Muscle Activities of Thoracic and Lumbar Extensors during Trunk Lift Exercises According to Exercise Position

The purpose of this study was to compare the muscle activities of the thoracic extensor(TE) and lumbar extensor(LE) during trunk lift (TL) exercise according to exercise position. Seventeen healthy subjects with no medial history of back pain were recruited for this study. Subjects performed the TL exercise in prone, quadruped and heel-sitting positions. The activities of the TE and LE were measured using surface electromyography during TL exercise in each exercise position. A one-way repeated-measures analysis of variance (ANOVA) was used to compare the normalized muscle activities of the TE and LE and the TE/LE ratio. The results showed that there was not significant effect of exercise position on the muscle activities of TE(p>.05). However, there was significant effect of exercise position on the muscle activities of LE and the TE/LE ratio(p>.05). Post hoc pair-wise comparisons with Bonferroni correction showed that both muscle activities of LE and TE/LE ratio in prone position were significantly different in those in heel-sitting and quadruped positions, during TL exercise, respectively. The TE/LE ratio was the greatest for TL exercise in heel-sitting position. Therefore, for selective activation of the TE muscle, we recommend performing the TL exercise in heel-sitting or quadruped position.