Spinal Reflex Arc Excitability Corresponding to the Vastus Medialis Obliquus and Vastus Medialis Longus Muscles

[Purpose] The gross morphology of the vastus medialis (VM) muscle has been thoroughly described. However, there is insufficient evidence of physiological differentiation between the VM obliquus (VMO) and VM longus (VML). To elucidate spinal reflex arc excitability in two divisions of the VM, we compared H-reflexes and T-waves in VMO and VML. [Subjects] Twenty-three healthy male volunteers participated in this study. [Methods] The H-reflex was evoked from the VMO and VML by electrical stimulation of the femoral nerve during knee extension at 10% maximal voluntary isometric contraction. Also, the patellar tendon was tapped by an examiner using an electrical tendon hammer, and a component of the compound muscle action potential (T-wave) was recorded. [Results] The configurations of the H-reflex and T-wave were sharp and slow in VMO and VML, respectively. No significant differences in the amplitudes of the H-reflexes and T-waves were observed between VMO and VML. The durations of VML H-reflexes and T-waves were significantly longer than those in VMO. [Conclusion] Spinal reflex arc excitability corresponding to VMO and VML was similar. However, the configurations and durations of the H-reflex and T-wave were differentiated with electromyography. On the basis of these findings, we suggest that VMO and VML are electrophysiologically distinct entities.Key words: Vastus medialis, H-reflex, T-wave     

Effects of Open and Closed Kinetic Chains of Sling Exercise Therapy on the Muscle Activity of the Vastus Medialis Oblique and Vastus Lateralis

[Purpose] The muscle strength of the quadriceps muscle is critical in patellofemoral pain syndrome. The quadriceps muscle supplies the power for dynamic patellar movement, and the vastus medialis oblique (VMO) and vastus lateralis (VL) enable the patella to stabilize during tracking. We followed the theories about open and closed kinetic chain exercises to design two exercises, sling open chain knee extension (SOCKE) exercise and sling closed chain knee extension (SCCKE) exercise. The purpose of our study was to research the changes in quadriceps muscle activity during both exercises. [Methods] Electromyographic analysis was used to explore the different effects of the two exercises. The MVC% was calculated for the VMO and VL during exercise for analysis. [Results] We found that the mean MVC% values of the VMO and VL during the SOCKE exercise were higher than those during the SCCKE exercise. The ratio of the VMO to VL was 1.0 ± 0.19 during the SOCKE exercise and 1.11 ± 0.15 during the SCCKE exercise. [Conclusions] The SOCKE exercise is targeted at quadriceps muscle training and has a recruitment effect on the VMO. The beneficial effect of the SOCKE exercise is better than that of the SCCKE exercise.Key words: Patellofemoral pain syndrome, Sling exercise therapy, Electromyography     

太极拳特定动作下股内侧肌和股外侧肌表面肌电特征的研究

目的 研究太极拳特定动作中股内侧肌(VMO)和股外侧肌(VL)的肌纤维募集情况.方法 收集15名健康志愿者在维持5个太极拳定势(白鹤亮翅、金鸡独立、搂膝拗步、十字手、仆步)时VL、VMO的表面肌电信号,比较平均肌电值(AEMG)、平均功率频率(MPF)、中位频率(MF)、零点通过率(ZCR).结果 维持白鹤亮翅、金鸡独立时,其支撑脚VMO、VL的所有指标均无显著性差异;维持搂膝拗步、十字手、仆步时,其支撑脚VL的AEMG、MFC、ZCR、MF均小于VMO(P<0.05);与股四头肌的最大随意收缩负荷相比,所测试的动作下,肌肉负荷属于中小负荷,并且能募集到更多的慢肌纤维.结论 进行太极拳运动时,肌肉负荷较小,并且能募集到更多的慢肌纤维;某些太极拳动作下,VMO可以较多地募集到肌纤维.     

膝骨关节炎患者与正常人股内侧肌、股直肌和股外侧肌收缩特征的对照研究

目的 应用表面肌电图和等速肌力评测方法比较膝骨关节炎患者与正常人股内侧肌、股直肌、股外侧肌肌肉收缩特征,包括收缩速度、收缩力量和抗疲劳性.方法 34例膝骨关节炎患者参与观察组;34名健康人参与对照组.两组的年龄、身高、体重、性别、左右侧、Q角相匹配.所有受试者均在膝关节屈曲10°、60°、100°等长伸膝和等速60°/s、180°/s伸膝运动测试模式下,进行股内侧肌、股直肌和股外侧肌的表面肌电图和股四头肌肌力的评测.采用独立样本 t检验对两组评定指标包括募集速率、平均振幅、峰力矩/体重比、疲劳指数分别进行对比分析.结果 ①观察组股内侧肌在膝屈60°等长伸膝测试和等速60°/s、180°/s伸膝测试中募集速率较对照组减小;股直肌在膝屈60°等长伸膝测试和等速60°/s伸膝测试中募集速率较对照组减小;股外侧肌在等长膝屈10°和100°伸膝测试和等速60°/s伸膝测试中募集速率较对照组减小( P＜0.05).②观察组股内侧肌、股直肌在等速60°/s、180°/s伸膝测试中平均振幅较对照组增大;观察组股直肌、股外侧肌在等长膝屈10°伸膝测试中平均振幅较对照组增大( P＜0.05).③观察组股内侧肌、股直肌和股外侧肌在膝屈10°、60°、100°等长伸膝和等速60°/s、180°/s伸膝运动测试模式中峰力矩/体重比均小于对照组( P＜0.05).④观察组在等速180°/s伸膝测试中股四头肌耐疲劳能力较对照组增强( P＜0.05).结论 膝骨关节炎患者患侧股内侧肌、股直肌和股外侧肌的收缩速度减慢、收缩力量减小、抗疲劳性增加.     

The Effect of Self-Myofascial Release on the Pennation Angle of the Vastus Medialis Oblique and the Vastus Lateralis in Athletic Male Individuals: An Ultrasound Investigation

BackgroundMaintenance of patellar stability requires a balance between the vastus medialis oblique (VMO) and the vastus lateralis (VL). The imbalance between these muscles is thought to be implicated in the etiology of patellofemoral pain (PFP). Where there is hypertrophy of the VL in PFP patients, self-myofascial release (SMR) may be utilized for its management. However, there is no current evidence regarding SMR and its effects on VMO and VL architecture. The aim of this study, therefore, was to use ultrasound to gain further understanding of the effects of a program of SMR on the fiber angles of the VMO and VL.HypothesisThere will be a significant decrease in the pennation angles of the VMO and VL after seven weeks of SMR using a foam roller.Study DesignCohort StudyMethodsTwenty-five young, athletic, male participants were recruited to use a foam roller, along the full length of both anterior thighs, three times weekly, on three separate days, for seven weeks. Ultrasound was used to determine the initial and final VMO and VL pennation angles on both limbs. One eligible participant was chosen as an intra-rater control and did not partake in the SMR regimen.ResultsThere was a statistically significant (p < 0.001) decrease in the pennation angles of the VMO and VL after the SMR regime. Mean combined right and left VL angle change was -6.65° (-18% mean change) and the mean combined right and left VMO angle change was -7.65° (-11.5% mean change). A weak negative correlation was found between initial VMO fiber angle and the angle change (Rsquared = -0.21), as well as moderate negative correlation for the VL (Rsquared = -0.51).ConclusionA program of SMR on the anterior thighs of young, asymptomatic males resulted in changes to the fiber angles of both the VMO and VL. There was a significant decrease in pennation angle after seven weeks of SMR using a foam roller.     

膝骨关节炎患者股内侧肌、股直肌和股外侧肌间的协调性

目的应用表面肌电图和等速肌力测定方法比较膝骨关节炎患者与正常人股内侧肌、股直肌和股外侧肌间的协调性改变。方法34例膝骨关节炎患者和34名膝关节健康者在膝关节屈曲10°、60°、100°等长伸膝和等速60°/s、180°/s伸膝运动测试模式下,进行股内侧肌(VM)、股直肌(RF)和股外侧肌(VL)的表面肌电图和股四头肌肌力的评测,包括肌肉激活启动顺序和VM/VL神经肌电比值。结果与正常人对比,膝骨关节炎患者在等速180°/s伸膝运动时VM相对于VL启动延迟（P＜0.05）;在膝屈10°等长伸膝运动时,VM/VL神经肌电比值降低（P＜0.05）。结论膝骨关节炎患者患侧股四头肌的协调性减退。     

Effect of Different Forefoot and Heel Support Surfaces on the Activities of the RF and HAM Muscles during the Sit-to-stand Task while Wearing High-heel Shoes

[Purpose] The purpose of this study was to show the effect of different forefoot and heel support surfaces on the activities of the rectus femoris and medial hamstring muscles during the sit-to-stand task while wearing high-heel shoes. [Subjects] Fifteen female subjects were recruited. [Methods] The muscle activities of the rectus femoris and hamstring muscles were recorded using an MP150 system during the sit-to-stand task while wearing various high-heeled shoes. [Results] The activities of the rectus femoris and medial hamstring muscles significantly decreased when subjects wore condition 1 shoes compared with when they wore condition 2, 3 or 4 high-heeled shoes. The activities of the rectus femoris and medial hamstring muscles significantly decreased when subjects wore condition 2 high-heeled shoes compared with condition 3 or 4 high-heeled shoes. [Conclusion] The results can be interpreted as indicating that the size of the forefoot supporting surface can influence the lower extremity muscles of women wearing high-heeled shoes more than the size of the heel supporting surface.Key words: High-heeled shoes, Imbalance, Sit-to-stand     

Rare Variant of Vastus Medialis Detected in vivo by Ultrasound and Confirmed by High-resolution MRI

[Purpose] This report describes an unusual incidental finding during ultrasound investigation of the vastus medialis muscle. Volunteers underwent ultrasound scanning as part of an on-going investigation into the architecture of the vastus medialis muscle. [Subjects and Methods] The distal thighs of forty-one subjects were scanned using the Philips iU22 US system. An unusual muscle morphology was detected bilaterally in one subject, who then underwent a 3T Magnetic Resonance Imaging (MRI) scan in order to further investigate the muscle morphology. The subject in question was a 32 year-old female who suffers from recurrent bilateral patellar dislocations. [Results] The MRI scan confirmed the ultrasound findings, and indicated the presence of the vastus medialis in two layers, with the VML continuing deep, separate from the VMO. [Conclusion] Although this rare variant has been been reported in previous cadaveric studies, we believe this to be the first report in the literature of this morphology in vivo. The biomechanical implications of this muscle arrangement are unknown, but it may not be without significance that this individual suffers from recurrent patellar dislocations.Key words: Vastus medialis, Ultrasound, MRI     

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.Key words: Bridge exercise, Muscle activity, EMG     

Effects of Trunk Stabilization Exercises on Different Support Surfaces on the Cross-sectional Area of the Trunk Muscles and Balance Ability

[Purpose] The purpose of this study was to examine the effects on stroke patients of trunk stabilization exercise on different support surfaces. [Subjects and Methods] Sixteen stroke patients with onset of stroke six months earlier or longer were randomly and equally assigned to group I (exercise performed on a stable support surface) and group II (exercise performed on an unstable support surface). The two groups conducted the trunk stabilization exercises on the respective support surfaces, in addition to existing rehabilitation exercises five times per week for 12 weeks. Changes in the cross-sectional area (CSA) of the muscles were examined using computed tomography (CT), and changes in the balance ability were assessed using a measuring system and the trunk impairment scale (TIS). [Results] In group I, there was a significant increase in the CSA of the mulifidus muscle on the side contralateral to the brain lesion and in the paravertebral and multifidus muscles on the side ipsilateral to the brain lesion. In group II, there was a significant increase in the CSA of the paravertebral and multifidus muscles on the side contralateral to the brain lesion and on the side ipsilateral to the brain lesion. In terms of changes in balance ability, the sway path (SP) and TIS significantly improved in group I, and the SP, sway area (SA), and TIS significantly improved in group II . [Conclusion] Exercise on the unstable support surface enhanced the size of the cross-sectional area of the trunk muscles and balance ability significantly more than exercise on the stable support surface.Key words: Cross-sectional areas, Trunk control, Balance     

Effect of Wrist Joint Restriction on Forearm and Shoulder Movement during Upper Extremity Functional Activities

[Purpose] This study measured %isolation and investigated whether it shows a difference between the presence and absence of wrist joint restriction, as well as changes in muscle activity patterns. [Methods] Twenty subjects performed upper extremity functional movement in the Manual Function Test (MFT) with and without wrist restriction, and the muscle activities of the trapezius, middle deltoid, biceps brachii, triceps brachii, extensor carpi radialis, and flexor carpi radialis were recorded. When there were differences in muscle activation, %isolation was implemented and the changes in the muscle activity patterns were noted. [Results] In the grasping and pinching tasks, there was a significant increase in %isolation of the upper trapezius and a significant decrease in %isolation of the extensor carpi radialis. Carrying a cube task, %isolation of the upper trapezius and middle deltoid significantly increased, whereas %isolation of the triceps brachii and extensor carpi radialis significantly decreased. In the pegboard task, the %isolation values of the extensor carpi radialis and flexor carpi radialis significantly decreased. [Conclusion] The data of this study should be useful for therapists, who can employ the information as material for the education and treatment of patients with wrist joint restriction. Therapists may thus look for ways to improve the quality of mobility by predicting the complement mobility depending on the activity performed and then determine whether to facilitate or restrict mobility.Key words: Functional upper extremity activity, %isolation, Wrist joint restriction     

Effect of Assistive Device for Neck Retraction (ANR) on Neck Muscles during Neck Retraction Exercise

[Purpose] The purpose of present study was to develop an exercise device for assisting neck retraction exercise and to investigate its effectiveness. [Subjects] Fifteen male subjects were recruited. [Methods] The subjects performed the neck retraction exercises with and without assistive device for neck retraction (ANR). EMG activities of the lower cervical erector spinae (LCE), and sternocleidomatoid (SCM) muscles were recorded. [Results] The ANR condition significantly increased LCE activation compared to the control condition. The ANR condition significantly decreased SCM activation compared to the control condition. [Conclusion] We suggest that the ANR condition will help the efficacy of the neck retraction exercise.Key words: Electromyography, Forward head posture, Neck retraction exercise     

Ultrasound Evaluation of Muscle Thickness Changes in the External Oblique, Internal Oblique,and Transversus Abdominis Muscles Considering the Influence of Posture and Muscle Contraction

[Purpose] The aim of this study was to investigate muscle thickness changes in the external oblique (EO), internal oblique (IO), and transversus abdominis (TrA) muscles between the neutral position and trunk rotation, under a state of rest without voluntary contractions, and isometric contractions to both sides with resistance of 50% of the maximum trunk rotation strength. [Subjects] The subjects of this study were 21 healthy young men. [Methods] Muscle thickness changes in the EO, IO, and TrA in each position and state were evaluated by ultrasound. The range of motion at maximum trunk rotation and the maximum strength of trunk rotation were measured using a hand-held dynamometer. [Results] In the neutral position and at 50% trunk rotation to the right side, the thicknesses of the IO and TrA significantly increased with resistance. In both states, the thicknesses of the IO and TrA significantly increased at 50% trunk rotation to the right side. [Conclusion] The muscular contractions of the IO and TrA were stronger during ipsilateral rotation than in the neutral position and with resistance than at rest. Moreover, the muscular contraction was strongest in the resistive state during ipsilateral rotation.Key words: Trunk rotation, Low back pain, Functional evaluation     

Reliability of Ultrasound Imaging of the Transversus Deep Abdominial, Internal Oblique and External Oblique Muscles of Patients with Low Back Pain Performing the Drawing-in Maneuver

[Purpose] The purpose of this study was to investigate the reliability of ultrasound imaging (USI) measurements of muscle thicknesses of patients with low back pain (LBP) performing the abdominal drawing-in maneuver (ADIM) [Subjects] Twenty patients with LBP were the subjects. [Methods] Muscle thickness measurements of transversus abdominis (Tra), internal obliques (IO), and external obliques (EO) muscles were measured using ultrasound imaging at rest and during performance of the ADIM. [Results] The intra-examiner reliability estimates ranged from 0.55 to 0.97 in the rest position, and from 0.82 to 0.95 during ADIM. The inter-examiner reliability estimates ranged from 0.77 to 0.98 in the rest position, and from 0.86 to 0.98 during ADIM. [Conclusion] ADIM thickness measurements of the TrA, IO, and EO muscles in patients with LBP based on the mean of 2 measures are highly reliable when taken by a single examiner and adequately reliable when taken by different examiners.Key words: Reliability, Abdominal drawing-in maneuver, Ultrasound imaging     

Electromyographic Activities of Trunk Muscles Due to Different Exercise Intensities during Pulley-based Shoulder Exercises on an Unstable Surface

[Purpose] This study examined the relationship between core stability and exercise intensity during a pulley-based shoulder exercise (PBSE) on an unstable support surface. [Subjects] Twenty healthy college students enrolled in this study. [Methods] Surface EMG was carried out in twenty healthy adult men. The electromyographic activities of the rectus abdominis (RA), erector spinae (ES), exercises with 14 kg or 26 kg of resistance and external oblique (EO) muscles during pulley-based shoulder on an unstable support surface (USS) were compared. [Results] The EMG signals of the RA, ES, and EO did not increase with increasing exercise resistance. [Conclusion] Increasing the exercise intensity to increase the core stability during PBSE on a USS may be ineffective.Key words: Electromyography, Core stability, Ankle strategy     

Influence of ROM Exercise on the Joint Components during Immobilization

[Purpose] The aim of this study was to clarify the effects of the ROM exercise on joint components according to histopathological analysis. [Subjects and Methods] In total, twenty-six 9-week-old adult male Wistar rats were used in this study. The rats were randomly divided into three groups, the immobilization group (n=10), exercise group (n=10), and control group (n=6). The immobilization group and exercise group were anaesthetized and operated on under sterile conditions. The right knee joints in the immobilization group and exercise group were immobilized with external fixation at 120 degrees of flexion. Range of motion exercise was started from the day after immobilization. ROM exercise was performed in the exercise group once a day for 3 minutes, 6 days a week, for 2 weeks. [Result] The joint capsule in the immobilization group and exercise group showed narrowing of the collagen bundles in interstitial spaces but was less dense in the control group. In the immobilized group, a hyperplastic reaction was associated with infiltration into the articular cavity and adhesion to the surface of the articular cartilage. Conversely, in the exercise group, hyperplasia of tissue was localized to the synovial membrane. [Conclusion] This finding may suggest that ROM exercise induces some changes within the joint components and tissue metabolism.Key words: Joint immobilization, Contracture, ROM exercise     

Effects of Bridging Exercise on Different Support Surfaces on the Transverse Abdominis

[Purpose] The purpose of this study was to identify the effects of bridging exercise on different support surfaces on the thickness of the musculus transversus abdominis and lower extremity muscle activities. [Subjects] Thirty-five students of H University. [Methods] The experimental group (n=18) performed bridging exercise on the sling support surface, and the control group (n=17) performed bridging exercise on a general support surface. [Results] Thickness changes in the musculus transversus abdominis were 0.35 cm in the experimental group, and 0.17 cm in the control group, suggesting that the experimental group showed a more significant change. For the lower extremity muscular activity, there was a significant difference between the experimental group and the control group only in the biceps femoris muscle. [Conclusion] Based on these results, we consider that bridging exercise on a sling support surface would increase the thickness of the transversus abdominis and lower extremity muscle activities in rehabilitation programs for patients with back pain.Key words: Bridging exercise, Sling exercise, Transversus abdominis     

Effect of Expiratory Muscle Fatigue on the Respiratory Response during Exercise

[Purpose] The aim of this study was to reveal the effect of expiratory muscle fatigue (EMF) on respiratory response under two different exercise conditions: exercise (EX) with EMF (EMF-EX) and control EX without EMF (CON-EX). [Methods] Nine healthy adult men performed cycle exercise with a ramp load, and a spirometer was used to measure forced vital capacity (FVC), forced expiratory volume in one second, percent of forced expiratory volume, maximal expiratory mouth pressure, and maximal inspiratory mouth pressure (PI_max) to evaluate respiratory functions immediately and at 15 and 30 min after exercise. To assess the respiratory response during exercise, an exhaled gas analyzer was used to measure minute ventilation (V_E), respiratory frequency (f), tidal volume (V_T), oxygen uptake, and carbon dioxide output. In addition, the Borg Scale was used to evaluate dyspnea, while electrocardiography was used to measure heart rate. [Results] The results showed that compared with the CON-EX condition, no change in V_E, an increase in f, or a decrease in V_T was observed under the medium-intensity EMF-EX condition, while high-intensity exercise reduced V_E and f without changing V_T. [Conclusion] These results suggest that during medium-intensity exercise, EMF modulates the respiratory response by inducing shallow and fast breathing to increase ventilation volume.Key words: Expiratory muscle fatigue, Maximal mouth pressure, Respiratory response