Background: The gluteus medius (Gmed) plays a critical role in maintaining frontal plane stability of the pelvis during functional activities, such as one-leg lifting. Side-lying hip abduction (SHA) has been used as a dynamic test to evaluate Gmed function. However, the abduction force of the lower leg against the floor is not controlled during SHA. Therefore, hip abduction performance with contralateral adduction in the side-lying position (HAPCA) can be proposed as an alternative method to assess performance of hip abduction. If the number of HAPCA is related to the lateral pelvic shift distance, a new quantitative measurement for hip abductor function may be presented. Objects: This study aimed to investigate the relationship between the number of successful HAPCA and the lateral pelvic shift distance during one-leg lifting. Methods: Thirty healthy participants were recruited, and lateral pelvic shift distance was measured during one-leg lifting test using two-dimensional analysis. The number of successful HAPCA was counted when participants touched both target bars at the beat of a metronome. Results: There was a negative correlation between the number of HAPCA and lateral pelvic shift distance during one-leg lifting (r = –0.630, p < 0.05). The number of HAPCA accounted for 39.7% of the variance in the lateral pelvic shift distance during one-leg lifting (F = 18.454, p < 0.001). Conclusion: The number of successful HAPCA is significantly correlated with lateral pelvic shift distance during one-leg lifting. This finding suggests that HAPCA can be proposed as a new measurement for hip abductor performance and more research is needed on its relationship with hip abductor strength.

목적：고관절 MRI 검사 중 대퇴비구 충돌을 일으키는 원인을 확인하고 진단하는 영상인 FAI MRI에서 다리를 내측으로 15° 회전시킨 상태로 유지하기 위하여 자체 개발한 보조기구를 이용하여 검사의 정확도를 유지하여 진단능력을 향상하고자 하였다. 대상 및 방법：2018년 3월부터 11월까지 고관절 충돌 증후군으로 의심되어 MRI를 검사한 환자 32명을 대상으로 하였고, 장비는 SIEMENS사의 Magnetom Skyra 3.0T를 사용하였다. 보조기구 사용 전, 후의 지방 소거 Proton Density 경사축 방향 영상과 보조기구 사용 후 3D Trufi영상을 얻은 후 clock- face의 3시 방향 재구성 영상 선택 후 알파 각을 측정하였다. 정성적 평가는 정형외과 고관절 전문의 1명과 영상의학과 근골격 전문의 1명이 보조기구 사용 전, 후의 지방 소거 Proton Density 영상으로 Anterior acetabular labrum, Posterior acetabular labrum, Anterior articular cartilage, Posterior articular cartilage를 관찰한 후 리커트(Likert scale) 5점 척도로 평가하였다. 측정을 통해 얻은 자료는 대응표 본 T 검정으로 유의한 차이를 분석하였다. 평가자 간 신뢰도 검증은 Cohen's weighted Kappa 검증을 통해 일치도를 검증 하였다. 결과：영상의 정량적 분석결과 보조기구 사용 전, 후 영상에서 각각 측정된 값의 차이를 비교 분석한 결과 보조기구 사용 전 평균값은 53.43±8.32로 나타났고 보조기구 사용 후 값은 52.09±8.34로 나타났다. 3D Trufi영상과 비교 분석한 결과 통계적으로 유의한 것으로 나타났다.(p<0.001) 정성적 평가를 위한 리커트 척도 결과 Anterior acetabular labrum 관찰 여부는 보조기구 사용 전 평균값은 2.78±0.74 보조기구 사용 후 평균값은 3.68±0.9로 나타났으며 통계적으로 유의하였다.(p<0.024) Anterior articular cartilage 관찰 여부는 두 평가자 간 차이가 거의 나타나지 않았으며 보조기구 사용 전 평균값은 4.53±0.51, 보조기구 사용 후 평균값은 4.39±0.8로 나타났으며, 통계적으로 유의하지 않았다.(p<0.103) Posterior articular cartilage 관찰 여부 역시 두 평가자 간 차이가 거의 없는 것으로 나타났으며 보조기구 사용 전 평균값은 4.37±0.47, 보조기구 사용 후 평균값은 4.36±0.7로 나타났으며, 통계적으로 유의하지 않았다.(p<0.232) Posterior acetabular labrum 관찰 여부는 보조기구 사용 전 평균값은 3.56±0.94 보조기구 사용 후 평균값은 4.51±0.63으로 나타났으며 통계적으로 유의하였다.(p<0.005) 평가 항목의 일치도 검증결과 높은 결과로 두 평가자 간 높은 신뢰도를 보여주었다. 결론：고관절 MRI 검사에서 자체 제작한 보조기구를 사용하여 발의 내전 15°를 유지하여 검사함으로써 대퇴비구 충돌 증후군 진단능력을 향상하고 향후 추적 관찰 검사에서도 정확하고 일관된 진단가치가 높은 영상을 제공함을 기대할 수 있고 긴 검사시간 동안 움직임에 의한 인공물 감소 및 환자 만족도를 향상할 수 있다는 점에 의의를 둘 수 있어 향후 보조 신발의 필요성과 개발에 필요한 기초자료를 제공하고자 한다.

Background:To improve lumbo-pelvic stability, passive support devices (i.e., a pelvic belt) are recommended clinically. Nevertheless, to understand the influence of passive support on lumbo-pelvic stability, it is necessary to examine the influence of a pelvic belt on the abdominal and hip abductor muscles.Objects:To examine the effects of a pelvic belt on the forces of the hip adductor and abductor muscles and activity of the abdominal muscles during isometric hip adduction and abduction.Methods:This study recruited 14 healthy men. All subjects performed isometric hip adduction and abduction with and without a pelvic belt in a neutral hip position. Load cells, wrapped with a non-elastic belt, were placed above the medial and lateral malleoli of the dominant leg to measure the muscle forces of the hip adductors and abductors, respectively. The forces of the hip adductors and abductors were measured using a load cell during isometric hip adduction and abduction, while the electromyographic activities of the bilateral rectus abdominis, internal oblique, and external oblique muscles were measured.Results:The forces generated by the hip adductors and abductors were significantly greater with the pelvic belt than without (p<.05). No significant differences in abdominal muscle activities between the two conditions were found (p>.05).Conclusion:These findings suggest that use of a pelvic belt could lead to effective strengthening exercise of hip muscles in individuals with sacroiliac joint pain.

Background: Several studies have discussed diverse exercise methods considered to be useful for the selective contraction of the vastus medialis oblique (VMO) muscle for the treatment of patellofemoral pain syndrome. Some studies have reported that exercise methods, including hip adduction, in closed kinetic chain exercises are more effective in terms of the muscle activation of the VMO and the timing of the muscle’s initial contraction. We focused on isometric contraction during a closed kinetic chain exercise with hip adduction. Objects: The purpose of this study was to examine muscle activation in the VMO and the vastus lateralis (VL) and the onset time difference between their initial contractions via closed kinetic chain isometric quadriceps femoris exercises including hip adduction. Methods: In total, 36 healthy subjects adopted two hip positions during isometric contraction of the quadriceps femoris in a closed kinetic chain exercise (hip neutral and hip adduction position). Statistical analyses were conducted using a paired t-test (α=.05). Results: Isometric contraction of the quadriceps femoris in a closed kinetic chain exercise caused a greater increase in VMO muscle activity in the hip adduction position [52.68±22.21 percentage of maximal voluntary isometric contraction (%MVIC)]than the hip neutral position (43.43±19.85 %MVIC). The onset time difference (VL-VMO) decreased more in the hip adduction position (-82.14±34.2 ㎳) than the hip neutral position (73.94±2.94 ㎳). Conclusion: We recommend this exercise as a clinically useful therapeutic method for patients with patellofemoral pain syndrome due to weakening of the VMO muscle and lateral inclination of the patella.

The purpose of this study was to determine the effect of contralateral hip adduction (CHA) on the muscle activity of lumbar stabilizers and the angle of pelvic lateral tilting during hip abduction in side lying. Twenty healthy male subjects with no medical history of lower extremity or lumbar spine disorders were recruited for the study. Subjects randomly performed preferred hip abduction (PHA) and hip abduction with contralateral hip adduction in side lying. The muscle activities of the dominant side rectus abdominis, external oblique, internal oblique, quadratus lumborum, gluteus medius, and non-dominant side hip adductor longus were measured during PHA and CHA by using a surface electromyography (EMG) system. Pelvic lateral tilting motion was measured by using a three-dimensional motion analysis system. Data on EMG and pelvic motion were collected at the same time during PHA and CHA. A paired t-test was used to compare EMG activity and the angle of pelvic lateral tilting in the two exercises. The study found that the EMG activities of all muscles were more increased significantly in CHA than PHA condition. The angle of pelvic lateral tilting was more decreased significantly in CHA than PHA condition. These findings suggest that CHA could be recommended as a hip abduction exercise for activating lumbar stabilizers and decreasing compensatory pelvic lateral tilting motion.

The purpose of this study was to determine the effect of contralateral hip adduction (CHA) on thickness of lumbar stabilizers during hip abduction in side-lying. Twenty healthy subjects without back pain were recruited for this study. The thickness of transverse abdominis (TrA), internal oblique (IO) and quadratus lumborum (QL) were measured by ultrasonography. Pelvic lateral tilting motion was measured using a three-dimensional motion analysis system. Measurements were performed at rest position (RP), preferred hip abduction (PHA) and abduction with contralateral hip adduction (CHA) in side-lying at the end of expiration. During the measurements, subjects were asked to maintain steady trunk alignment without hand support. Thickness of TrA and IO was significantly greater in CHA than in PHA and RP conditions. There was no significant difference in thickness of TrA and IO between PHA and RP conditions. Medio-lateral (M-L) thickness of QL was not significant between PHA and CHA conditions. Anterio-posterior (A-P) thickness of QL in PHA and CHA significantly decreased compared to RP condition. Angle of pelvic lateral tilting was significantly decreased in CHA compared to PHA condition. In conclusion, CHA can be recommended for increasing trunk stability without compensatory pelvic motion during hip abduction exercise in side-lying.

The purpose of this study was to determine whether the vastus medialis oblique muscle(VMO) had greater electrical activity than the vastus lateralis muscle(VL) when hip adduction and knee extension exercise were performed. Electrical activity of the VMO and VL was measured on 42 healthy subjects (28 men, 14 women) during maximal voluntary isometric contractions of hip adduction and knee extension by an EMG-BIOFEEDBACK. The results showed that the electromyographic activity of the VMO was significantly greater than that of the VL during the hip adduction exercise. Differences noted with knee extension by performing hip adduction exercises. Isometric hip adduction exercises, therefore, may be advisable in the treatment of patients with patellofemoral pain.