Background: Shoulder external rotation exercises are commonly used to improve the stabilizing ability of the infraspinatus. However, during exercise, excessive activation of the posterior deltoid compared to the infraspinatus causes the humeral head to move anteriorly in an abnormal position. Many researchers have emphasized selective activation of the infraspinatus during shoulder external rotation exercise. Objects: This study aims to delineate the optimal exercise method for selective activation of infraspinatus by investigating the muscle activities of the infraspinatus and posterior deltoid according to the four shoulder exercise methods and two forearm positions. Methods: Thirty healthy individuals participated in this study. The participants were instructed to perform shoulder external rotation exercises following four exercise methods: sitting external rotation (SIER); standing external rotation at 90° abduction (STER); prone external rotation at 90° abduction (PRER); side-lying external rotation (SLER), and two forearm positions (neutral, supinated). The electromyography (EMG) signal amplitude was measured during each exercise. Surface EMG signals were recorded from the posterior deltoid, infraspinatus, and biceps brachii. Results: EMG results of the infraspinatus and posterior deltoid in PRER, were significantly higher than that of the other exercises (p < 0.01). The EMG ratio (infraspinatus/posterior deltoid) in SIER was significantly higher than that of the other exercises. EMG activation of the posterior deltoid in SIER, PRER, and SLER was significantly higher in neutral than in supinated (p < 0.01). Furthermore, the EMG of the infraspinatus in SIER was significantly higher in neutral than in supinated (p < 0.01). The EMG ratio (infraspinatus/ posterior deltoid) in SIER was significantly higher in neutral than in supinated (p < 0.05.) Contrarily EMG ratios in PRER and SLER were significantly higher in supinated than in neutral (p < 0.05). Conclusion: The results show that clinicians should consider these exercise methods and forearm positions when planning shoulder external rotation exercises for optimal shoulder rehabilitation.

이 연구의 목적은 6주간의 엉덩관절 강화 훈련이 근력, 동적 자세 조절 및 하체 손상 준거에 미치는 영향을 보고자 하였다. 운동선수 20명을 운동군과 통제군으로 분류하여, 운동군은 주 3회, 60분, 6주간 엉덩관절 강화훈련을 하였다. 이 연구의 측정 변인은 유연성, 근력, 동적 자세 조절 및 하체 부상 준거로 하였다. 연구 결과 유연성에서 운동의 효과가 유의하지 않았으나 배근력에서는 유의하였다. 동적 자세 조절 결과, 좌·우 후방 가쪽 및 안쪽에서 운동의 효과가 유의하였다. 또한 종합점수에서도 운동의 효과가 유의하였고, 좌·우 다리 간의 차이는 없었다. 결론적으로 엉덩관절 강화 운동은 근력과 동적 자세 조절 능력의 증가와 하체 손상의 우려는 감소시키는 것으로 나타났다.

Background: The scapulo-thoracic musculatures including serratus anterior (SA), upper trapezius and lower trapezius can provide shoulder stability and functional shoulder movement. Objects: The muscle activities of upper and lower SA were compared during three different scapular protraction exercises in healthy individuals in sitting position. Methods: Twenty-five healthy subjects were participated. Electromyography device was used to measure muscle activity of upper and lower SA and trapezius muscles. Each subject was asked to perform three different scapular protraction exercises (scapular protraction [SP], SP with self-resistance [SPSR], SPSR with hand-exerciser [SPSRH]) in random order. One-way repeated measures analysis of the variance and a Bonferroni post hoc test were used. Results: The muscle activity of lower SA muscle was significantly different among three conditions (SP vs. SPSR vs. SPSRH) (p < 0.01). The lower SA muscle activity was significantly greater during SPSRH compared to SP and SPSR, which required joint stability more than SP and SPSR (p < 0.01). Conclusion: SPSRH exercise can be recommended to facilitate the muscle activity of lower SA. In addition, the intramuscular variation in the upper and lower SA during scapular protraction exercise is required to consider the effective rehabilitation.

Background: Backward walking exercise may offer some unique and potentially beneficial differences compared with forward walking exercise. There is still a lack of research on backward walking exercises and forward head posture. Objects: The purpose of this study was to determine the effect of backward walking exercise on college students forward head posture in their 20s. Methods: Twenty-one subjects participated in the experiment. The subjects were those with a craniovertebral angle (CVA) of 55 degrees or less who understood the purpose and method of this study and voluntarily agreed. A camera capable of taking pictures of the lateral plane was installed at a distance of 1.5 meters before exercising. Pictures were taken before walking backward, and after walking for 15 minutes on the treadmill, the images were taken in the same way. The composition of the backward walking exercise was walking at a rate of 1.0 for 5 minutes, and the remaining 10 minutes were walking at a rate of 1.5. Wilcoxon signed rank test was used to compare CVA and craniorotational angle (CRA) before and after exercise. Results: As a result of this study, there was a significant difference in CVA before and after exercise (p < 0.05). There was a significant difference in CRA before and after exercise (p < 0.05). Conclusion: The backward walking exercise and verbal command seems to have positively influenced the changes in CVA and CRA among college students in their 20s. It seems that studies to confirm balance or muscle activity as well as changes in forward head posture through the long-term intervention of the backward walking exercise should be conducted.

Background: Individuals with mechanical neck pain show biomechanical and neurophysiological changes, including cervical spine muscle weakness. As a result of deep muscle weakness, it causes stability disability and reduced upper thoracic spine mobility, which finally leads to functional movement restriction such as limited range of motion and dysfunction. Recent studies have shown that thoracic spine manipulation and mobilization could reduce symptoms of mechanical neck pain in patients. Objects: The purpose of this study was to investigate the effects of thoracic mobility exercise on cervicothoracic function, posture feature, and pain intensity in individuals with mechanical neck pain. Methods: The study subjects were 26 persons who were randomly assigned to the experimental (with thoracic mobility exercise) and control groups (without thoracic mobility exercise), with 13 subjects in each group. The cervicothoracic function (neck functional disability level and cervicothoracic range of motion), posture feature, and pain rating (using a quadrupled visual analogue scale [QVAS]) were measured before, after 3 weeks, and after 6 weeks. Results: Statistically significant group-by-time interactions were found with repeated analyses of variance for the Korean neck disability index (KNDI), all cervical range of motion (CROM), all thoracic range of motion (TROM), cranial rotation angle, sagittal shoulder posture (SSP), and QVAS (p<.05). All groups showed significant improvements from all times in all the evaluated methods. The KNDI, CROM, TROM of left rotation, and SSP in the experimental group showed significant improvements after 3 weeks, and the TROM of the right rotation and QVAS in the experimental group showed significant improvements after 6 weeks when compared with the control group. Conclusion: Thoracic mobility exercise during 6 weeks might be effective intervention to improve the functional level, posture feature, and QVAS pain rating for managing individuals with mechanical neck pain.

본 연구는 스탠스 자세와 운동면의 차이가 어깨돌림동작 시 활동근의 %MVIC를 비교분석하여 어깨강화운동을 위한 기초자료를 제공하는데 목적이 있다. 남성 8명을 무선배정하여 두발지지 자세, 한발지지 자세, 런지자세와 이마면, 수평면, 시상면에서 회전동작을 10회씩 수행하였다. 수행 중 가시위근, 가시아래근, 작은원근, 앞세모근, 배곧은근, 척수세움근, 큰가슴근, 넓은등근의 근활성도를 측정하였다. SPSS 22.0 통계프로그램을 사용하여 반복측정 일원분산분석(repeted one-way ANOVA)을 실시하였다. 첫째, 이마면에서 바깥돌림 동작 시 척추세움근은 두발지지 자세와 한발지지 자세보다 런지자세에서 높게 나타났고 안쪽돌림 동작 시 가시위근은 두발지지 자세보다 한발지지 자세, 한발지지 자세보다 런지자세에서 높게 나타났다. 둘째, 수평면에서 바깥돌림 동작 시 앞세모근은 두발지지 자세보다 한발지지 자세과 런지자세에서 높게 나타났고 안쪽돌림 동작 시 가시아래근은 두발지지 자세와 한발지지 자세보다 런지자세에서 높게 나타났으며, 큰가슴근에서는 한발지지 자세보다 두발지지 자세, 한발지지 자세보다 런지자세가 높게 나타났다. 셋째, 시상면 바깥돌림 동작 시 배곧은근은 두발지지 자세보다 한발지지 자세와 런지자세에서 유의하게 높게 나타났다. 안쪽돌림 동작 시 가시위근은 두발지지 자세보다 한발지지 자세와 런지자세에서 높게 나타났고 가시아래근은 두발지지 자세와 한발지지 자세보다 런지자 세에서 높게 나타났다. 배곧은근에서 두발지지 자세와 런지자세보다 한발지지 자세에서 높게 나타났고 척추세움근은 한발지지 자세보다 두발지지 자세와 런지자세에서 높게 나타났다. 결론적으로 스탠스와 어깨의 운동면의 차이가 어깨위팔관절의 돌림운동 시 활동근들의 근활성도에 미치는 영향은 스탠스자세와 운동면에 따라서 다른 양상이 나타났으며, 이를 어깨 강화 운동프로그램에 적용한다면 보다 긍정적 효과를 기대할 수 있는 운동프로그램이 될 것으로 생각 된다.

Background: High string instrument (violin, viola) players are at high risk for developing musculoskeletal problems. In particular, a higher prevalence of shoulder problems has been reported. However, evidence of the effectiveness of therapeutic exercise for musicians with this condition is lacking until now. Objects: This case series study investigated the effect of a specific exercise program on shoulder pain, dysfunction, and posture of professional orchestral high string musicians. Methods: Five professional orchestral high string players with shoulder pain participated in this study. A six-week specific exercise program focus on scapular stability for shoulder pain consisted of scapular muscle exercise. Physical examinations for pain and dysfunction, posture were performed, were identified among all subjects before starting the exercise program. Results: The results revealed that shoulder pain decreased by 67.86% and the effect of pain on instrument play decreased by 63.33%. The shoulder pain and disability Index and the performing arts module-quick disability of the arm, shoulder and hand scale decreased by 71.72% and 51.61% respectively. The exercise program improved function and posture. Conclusion: A specific exercise program for high string players was effective in managing shoulder pain. This case series is intended to provide empirical data on the effectiveness of an exercise program aimed at assessing the effect of exercise on pain, dysfunction, and posture of professional orchestra musicians associated with specific instrument groups.

Background: Short foot exercise (SFex) is often prescribed and performed in the sport and rehabilitation fields to strengthen intrinsic foot muscles. However, SFex is difficult to perform because of lack of feedback methods. Objects: The aim of this study was to compare the effects of SFex with and without electromyography (EMG) biofeedback on the medial longitudinal arch (MLA) of healthy individuals who maintained a static standing position. Methods: All participants (14 males and 12 females) were randomly divided into two groups (biofeedback and non-biofeedback groups). The EMG activity of the abductor hallucis (AbdH) and tibialis anterior (TA) and the MLA angle on the dominant leg side were measured with the participant in the standing position in the pre- and post-intervention conditions. The intervention session consisted of 15 minutes of SFex with (biofeedback group) or without (non-biofeedback group) EMG biofeedback. The groups were compared using two-way repeated measures analysis of variance. Results: The post-intervention activities of the AbdH muscle (p<.05) and the AbdH/TA ratio (p<.05) were significantly greater in the biofeedback group than in the non-biofeedback group. The activity of the TA (p<.05) and the MLA angle (p<.05) in the biofeedback group were significantly lower in the post-intervention condition than in the pre-intervention condition. Conclusion: The present findings demonstrate that the combination of SFex and EMG biofeedback can effectively facilitate the muscle activity of the AbdH and strengthen the medial longitudinal arch.

본 연구에서는 살포비행의 주된 요운동과 순항비행에 대하여 시뮬레이션과 비행실험을 통해 얻은 적정 제어이득을 적용하여, 농용헬리콥터의 수동과 제어비행에서 순항비행 및 요의 행동을 비교하였다. 수동의 경우는 조종간의 입력 즉, 서보의 입력은 그대로 서보의 출력으로 전달되어 헬리콥터의 비행자세와 반응으로 나타나므로 조종자에 있어 높이와 자세를 유지하는데 높은 숙련도와 노력이 필요하였다. 반면 상용제어기의 적용은 기본적인 자세 및 요의 제어를 제공 받으므로 조종자가 살포작업에 편이성을 제공받을 수 있었다. 수동비행에서 요각의 행태는 편류비행의 결과를 보였으나, 제어에서는 목표진행 방위각에서 안정되게 유지되었다. 또한 수동 순항비행에서는 롤 및 피치각의 자세가 숙련된 조종자에 의해 ±6.9°(±0.11 rad) 정도의 롤 및 피치각의 큰 변동폭을 경험하였다. 반면 자세제어 비행에서는 ±2.8°(±0.05 rad) 정도의 안정된 변동폭을 유지하였다. 따라서, 상용제어기를 적용함으로써 요운동으로 방향을 유지하고 순항비행에서 살포높이와 속도를 조절하는데 조종자의 편이성을 제공 할 수 있을 것으로 생각되었다.

The aim of this study was to investigate the effects of different postural correction in the electromyographic (EMG) activity of the trunk and hip muscles during bridging exercises. Twenty-four healthy subjects volunteered for this study. The muscle activity was recorded with surface electrodes over the erector spinae, multifidus, gluteus maximus (GM), and hamstring (Ham) muscles; it was measured by using surface EMG equipment under the following 3 experimental conditions: manual postural correction, verbal correction, and no correction. The maximal voluntary isometric contraction (MVIC) was determined for each muscle group in order to represent each exercise as a percentage of MVIC and allow for standardized comparison between subjects. A one-way analysis of variance was used to determine significant differences in the EMG activities of each muscle between the 3 experimental groups. During bridging exercises, the manual postural correction on normalized EMG activity of the GM muscle during manual guiding was significantly higher than during verbal guiding and without guiding (p<.05). Furthermore, the GM/Ham ratio was significantly higher during manual guiding than during verbal guiding and without guiding (p<.05). These findings suggest that the activities of the hip and trunk muscles may be favorably modified with manual guiding during bridging exercises.

The aim of this study is to compare measurements of abdominal muscle thickness using ultrasonography imaging (USI) to those using a special transducer head device, during five different trunk stabilization exercises, ultimately to determine which exercise led to the greatest muscle thickness. Thirty eight healthy subjects participated in this cross-sectional study. The five types of trunk stabilization - i.e., a sit-up on the supine, an upper and lower extremity raise with quadruped on the prone, a leg raise in sitting on the ball, trunk rolling on the ball, and balance using sling on the prone position - were each performed with an abdominal draw. The thickness of the abdominal muscle - including the transverse abdominal (TrA), internal oblique (IO), and external oblique (EO) - was measured by USI with a special transducer head device, at rest and then at contraction in each position. Data were analyzed using one-way repeated ANOVA with the level of significance set at =.05. The results were as follows: 1) the TrA thickness was statistically significant (p<.05), whereas the IO and EO thicknesses were not (p>.05); 2) among the five types of trunk stabilization, TrA thickness significantly increased with the balance using a sling in the prone position, (p<.05), whereas no significant difference was noted for the four types of trunk stabilization (p>.05); 3) reliability data showed that there was a high degree of consistency among the measurements taken using the special transducer head device (ICC=.92). In conclusion, the balance using a sling in the prone position was more effective than any of the four other types of trunk stabilization in increasing TrA thickness in healthy subjects.

The purpose of this study is to examine the activity ratios of global trunk muscles and local trunk muscles in relation to adjustments in the level of task difficulty while performing stability exercises in easily applied bridging lumbar stabilization exercise. Twenty healthy subjects performed bridging lumbar stabilization exercise while the level of task difficulty was plate was used in the same posture for all the exercises. EMG was used to examine the activity ratios of the global muscles and multifidus in relation to the level of task difficulty. Moreover, the activity ratios of the multifidus muscle, the erector spinae and the gluteus maximus muscle were measured. A one-way ANOVA with repeated measures was used, and a Bonferroni correction was conducted (=.05). When the bridging lumbar stabilization exercise were performed at different difficulty levels, the activity of the multifidus muscle, which is a local muscle, was high in all three exercises. Also, compared to low intensity and intermediate intensity exercises, high intensity exercises showed more significant differences (=.05). Among all the muscles, the multifidus showed the highest activity at intermediate intensity. Based on these results, we suggest that in the case of bridging lumbar stabilization exercise, low intensity or intermediate intensity exercises are more suitable and efficient for local muscle stabilization.

목적 : 자세조절과 시지각 능력은 일상생활 및 학습을 하는 데 있어 기초가 되고 이러 한 요소는 뇌성마비 아동을 치 료하는데 주된 목표가 된다. 따라서 본 연구를 통해 경직형 뇌성마비 아동에서 안구운동프로그램이 자세조절과 시 지각 능력에 미치는 영향을 알아보고자 한다. 연구방법 : 2010년 5월 1일부터 2010년 8월 31일까지 부산에 위치한 P복지관에 내원하는 만4세~8세 경직형 뇌 성마비 아동을 대상으로 하였다. 10명의 경직형 뇌성마비 아동을 무작위로 실험군과 대조군으로 각각 5명씩 배정 하였다. 실험군에게는 안구운동프로그램과 함께 일반적 작업치료를 제공하고 대조군에게는 일반적 작업치료를 시 행하였다. 안구운동 프로그램은 단속성안구운동, 이접안구운동, 추적안구운동, 전정안구운동 4가지로 구성되어 있 다. 활동 중재는 1회 40분씩 주 3회로 8주 동안 제공되었다. 중재 전∙후에 대한 평가는 대동작기능평가(GMFM), 소아균형척도(PBS), 소아뻗기검사(PRT)와 한국판시지각발달검사(K-DTVP)를 사용하였다. 결과 : 안구운동프로그램을 수행한 실험군에서는 GMFM, PBS, PRT와 시각통합을 제외한 K-DTVP 모든 하위평 가항목에서 중재 전과 후의 점수가 통계적으로 유의한 차이가 있는 것으로 나타났으나(p<.05), 대조군에서는 PRT와 K-DTVP의 눈손협응과 공간위치를 제외하고는 통계적으로 유의한 차이를 보이지 않았다. 또한 두 집단 의 평가 점수의 변화량을 비교하였을 때 모든 평가항목에서 실험군이 대조군에 비해 유의한 차이를 보여 자세조절 과 시지각 기능 향상이 대조군보다 더 좋음을 나타냈다(p<.05). 결론 : 본 연구는 경직형 뇌성마비 아동에서 안구운동프로그램 중재가 자세조절 및 시지각능력 향상에 효과적임을 시사한다.

The aim of this study was to compare electromyography activity for long and lateral heads of triceps brachii muscle according to forearm positions during different triceps strengthening exercises. The muscle activities for long and lateral head of triceps brachii were measured by surface electromyography. Fifteen healthy volunteers participated for this study and performed elbow extension in three different elbow extension exercises (elbow extension in a supine position; EES, elbow extension with shoulder abduction at 90 degrees in a prone position; EESA, and elbow extension with one arm at the side of the trunk in a prone position; EESP) and forearm positions (supination, neutral, and pronation). A two-way repeated measures ANOVA was used to compare the effects of the exercise positions and forearm positions. The EMG activities of the long head of the triceps brachii increased significantly during EESP with forearm supination, whereas the activity of the lateral head of the triceps brachii increased significantly during EESA with the forearm in a neutral position (p<.05). The results of this study suggest that exercise positions and forearm positions should be considered for selectively strengthening the long and lateral heads of triceps brachii muscles.

The purpose of this study was to assess visual biofeedback's influence on trunk muscles' (EMG) activity and endurance holding time for correct position during whole-body tilt exercise. For the study, we recruited 14 volunteers who showed no symptom of lumbar disease during medical tests. We measured the EMG activity of their rectus abdominis, external abdominal oblique, internal abdominal oblique and erector spinae muscles, and their endurance holding time for correct position during anterior and posterior whole-body tilt under two conditions: whole-body tilt with and without visual biofeedback. Resistance with gravitational force on the trunk during whole-body tilt was applied by using a device that had a monitor on which the subjects could check their alignment and that sounded an alarm if a subject's alignment collapsed. The study showed an increase in the EMG activity of external abdominal oblique, internal abdominal oblique/rectus abdominis ratio and endurance holding time for correct position during both anterior and posterior whole-body tilt with visual biofeedback compared with without visual biofeedback (p<.05). We suggest that the whole-body tilt exercise with visual biofeedback could be a beneficial strategy for selectively strengthening the internal abdominal oblique muscle and minimizing the rectus abdominis muscle's activity while maintaining correct alignment during whole-body tilt exercise.

This study examined the vastus medialis oblique (VMO) and the vastus lateralis (VL) onset time differences (OTD) during quadriceps contraction in different hip positions. Twelve healthy subjects were recruited (four men, eight women). Surface EMG activities of the VMO and VL were measured during a quadriceps strengthening exercise in a long sitting condition and in a sitting at a chair with feet hanging condition. For each condition, subjects were tested in two hip positions (neutral and adduction). The OTD between the two muscles was calculated for each condition, by subtracting the onset time of the VL from the VMO. Therefore, the negative value of OTD represent earlier EMG onset of the VMO compared to the VL. The OTD was not significantly different between the hip neutral and the hip adduction position in the long sitting condition (p=.064). However, the OTD was significantly different between the hip neutral position (15.83±109.51 ms) and hip adduction position (-5.58±121.08 ms) during the sitting at a chair with feet hanging condition (p=.047). The negative OTD value in the hip adduction condition during quadriceps strengthening exercises is the result of earlier onset of the VMO than VL. Therefore, quadriceps contraction in the hip adduction position can prevent the risk of patella lateral tracking. We expect that quadriceps strengthening exercise in the hip adduction position will be a safe way to prevent patellofemoral pain syndrome resulting from abnormal patella lateral tracking.

The purposes of this study were to compare abductor hallucis (AbdH) muscle activity during toe curl exercise according to position of interphalangeal joint (IPJ). Fifteen healthy subjects with neutral foot were recruit for this study. All subjects performed toe curl exercise with towel while maintaining the IPJ in flexion (condition 1) and extension (condition 2). Toe curl exercise with towel was perform three trials for five second periods in each condition. Surface electromyography (EMG) activities were recorded from three muscles (AbdH, tibialis anterior, peroneous longus) in each condition. EMG activity was normalized to the value of maximal voluntary isometric contraction (%MVIC). The EMG activities acoording to position of IPJ were compared using a paired t-test. This study showed that the EMG activity of AbdH during toe curl exercise with IPJ extension significantly increased compared to those during toe curl exercise with IPJ flexion (p<.05). However, the EMG activity of tibialis anterior and peroneus longus were not significantly different between the conditions (p>.05). These results suggest that toe curl exercise with towel must be performed with extension of IPJ in order to strengthen intrinsic muscle in subjects with overuse injuries related to excessive pronation.

Although many children with cerebral palsy have problems with their eye movements available data on its intervention is minimal. The purpose of the study was to determine the effectiveness of the postural movement normalization and eye movement program on the oculomotor ability of children with cerebral palsy. Twenty-four children with cerebral palsy (12 male and 12 female), aged between 10 and 12, were invited to partake in this study. The subjects were randomly allocated to two groups: an experimental group received the postural movement normalization and eye movement program and a control group which received conventional therapy without the eye movement program. Each subject received intervention three times a week for twelve weeks. The final measurement was the ocular motor computerized test before and after treatment sessions through an independent assessor. Differences between the experimental group and control group were determined by assessing changes in oculomotor ability using analysis of covariance (ANCOVA). The changes of visual fixation (p<.01), saccadic eye movement (p<.01) and pursuit eye movement (p<.01) were significantly higher in the experimental group than in the control group. These results show that the postural movement normalization and eye movement program may be helpful to treat children with cerebral palsy who lose normal physical and eye movement.

This study was designed to identify the effect of various decline boards and postures of lower extremities on surface electromyographic (EMG) activity of knee muscles during isometric single-leg decline squat exercises. The subjects were twenty young male adults who had not experienced any knee injury and their Q-angles were within a normal range. They were asked to perform single-leg decline squat exercises in five various conditions. The EMG activities of the gluteus maximus (GM), vastus lateralis (VL), vastus medialis (VMO), tibialis anterior (TA), and gastrocnemius (GCM) muscles were recorded in five various single-leg decline squat exercises by surface electrodes and normalized by maximal voluntary isometric contraction (MVIC) values. The normalized EMG activity levels were compared using one-way ANOVA with repeated measures. The results of this study were as follows: 1) Exercises 2 and 4 produced significantly greater EMG activity of VMO than did exercise 1 (<.05/10), 2) The VMO/VL ratio of EMG activity of exercise 4 was the highest, producing a significantly greater ratio than exercise 1 (<.05/10). These results show that single-leg lateral oblique decline squat exercise is the best exercise for selective strengthening of VMO, and the posture of the contralateral leg does also affect strengthening of VMO, but we'll need to research patellofemoral joint compression for clinical application of single-leg lateral oblique decline squat exercises.