Evaluation of Open and Closed Kinetic Chain Exercises in Rehabilitation Following Anterior Cruciate Ligament Reconstruction

[Purpose] To compare outcomes of anterior cruciate ligament (ACL) reconstruction after open kinetic chain (OKC) exercises and closed kinetic chain (CKC) exercises. [Subjects and Methods] The subjects comprised 11 female and 47 male patients who are randomly divided into two groups: which performed a CKC exercise program Group I and Group II which performed an OKC exercise program. Pain intensity was evaluated using visual analogue scale (VAS). Knee flexion was evaluated using a universal goniometer, and thigh circumference measurements were taken with a tape measure at baseline and at 3 months and 6 months after the treatment. Lysholm scores were used to assess knee function. [Results] There were no significant differences between the two groups at baseline. Within each group, VAS values and knee flexion were improved after the surgery. These improvements were significantly higher in the CKC group than in the OKC group. There were increases in thigh circumference difference at the 3 and 6 month assessments post-surgery. A greater improvement in the Lysholm score was observed in the CKC group at 6 months. [Conclusion] The CKC exercise program was more effective than OKC in improving the knee functions of patients with ACL reconstruction.Key words: Anterior cruciate ligament reconstruction, Closed kinetic chain exercises, Open kinetic chain exercises     

Differences in Muscle Activities of the Infraspinatus and Posterior Deltoid during Shoulder External Rotation in Open Kinetic Chain and Closed Kinetic Chain Exercises

[Purpose] This study investigated the changes in electromyographic (EMG) activities of the infraspinatus and posterior deltoid muscles during shoulder external rotation under open kinetic chain (OKC) and closed kinetic chain (CKC) exercise conditions. [Subjects] In total, 15 healthy males participated in this study. [Methods] Subjects performed shoulder external rotations under CKC and OKC conditions while standing with and without weight support provided by a height-adjustable table. Pressure biofeedback was used to ensure a constant amount of weight support. The activities of the infraspinatus and posterior deltoid muscles during shoulder external rotation were measured using a wireless surface EMG system. The paired t-test was used to compare the EMG activities of the infraspinatus and the posterior deltoid muscles and the ratio of the infraspinatus to the posterior deltoid during shoulder external rotation under OKC and CKC conditions. [Results] The EMG activity of the infraspinatus and the ratio of the infraspinatus to the posterior deltoid activities were significantly increased, whereas the posterior deltoid activity was significantly decreased under the CKC condition compared to the OKC condition. [Conclusion] Clinicians should consider the CKC shoulder external rotation exercise when they wish to selectively strengthen the infraspinatus.Key words: Infraspinatus, Posterior deltoid, Selective muscle strengthening     

Understanding the Active Straight Leg Raise (ASLR): An electromyographic study in healthy subjects

The Active Straight Leg Raise (ASLR) is an important test in diagnosing pelvic girdle pain (PGP). It is difficult to understand what happens normally during the ASLR, let alone why it would be impaired in PGP. In the present study, healthy subjects performed the ASLR under normal conditions, with weight added above the ankle, and while wearing a pelvic belt. Activity of the abdominal muscles, rectus femoris (RF), and biceps femoris (BF) was recorded with surface electromyography (EMG), and transversus abdominis (TA) with fine wire EMG. RF was ipsilaterally active, BF contralaterally, and the abdominal muscles bilaterally. All muscle activity was higher with weight, and abdominal muscle activity was lower with the pelvic belt. In both these conditions, TA and obliquus abdominis internus (OI) were more asymmetrically active than obliquus externus. The abdominal muscles engage in multitasking, combining symmetric and asymmetric task components. Hip flexion causes an unwanted forward pull on the ipsilateral ilium, which is counteracted by contralateral BF activity. To transfer this contralateral force toward ipsilateral, the lateral abdominal muscles press the ilia against the sacrum (“force closure”). Thus, problems with the ASLR may derive from problems with force closure. Also abdominal wall activity counteracts forward rotation of the ilium. Moreover, contralateral BF activity causes transverse plane rotation of the pelvis, often visible as an upward movement of the contralateral anterior superior iliac spine. Such transverse plane rotation is countered by ipsilateral TA and OI. The present study facilitates the understanding of what normally happens during the ASLR.     

A comparison of EMG output of four lower extremity muscles during selected yoga postures

The purpose of this study was to use surface electromyography (EMG) analysis to examine the muscle activation of the anterior tibialis (TA), gastrocnemius (GA), rectus femoris (RF) and biceps femoris (BF) muscles during several yoga poses: tree pose (Vrksashana), half moon pose (Ardha Chandrasana) and warrior III (Virabadrasana) when compared to a rest pose (mountain pose). Ten healthy females with more than 3 months of continuous yoga experience who practiced at least 1.5 h per week were recruited. EMG activity was recorded from the aforementioned muscles during mountain pose (“rest”) for 30 s, three times. Subjects then performed the following yoga poses in a randomized sequence while surface EMG activity was recorded: tree pose, half-moon, and warrior III. Each pose was held for 20s to 30 s and performed three times. EMG data were band pass filtered and the root mean square (RMS) was obtained. The peak RMS of each of the resting trials was obtained and averaged to produce an average peak resting RMS value. The study revealed significantly greater EMG activity in TA and GA in all three poses when compared to BF and RF. BF produced greater EMG activity than RF in warrior III. In conclusion, single limb yoga poses require increased use of the ankle musculature when compared to thigh musculature.     

The Effects of Open versus Closed Kinetic Chain Exercises on Patients with ACL Deficient or Reconstructed Knees: A Systematic Review

Background

There is no consensus among the existing published evidence as to whether closed kinetic chain (CKC) or open kinetic chain (OKC) exercises should be the intervention of choice following an anterior cruciate ligament (ACL) injury or reconstruction. The commonly held belief has been that OKC exercises cause increased strain on the ACL as well as increased joint laxity and anterior tibial translation.

Objective

To investigate the effects of OKC and CKC exercises on the knees of patients with ACL deficiency or reconstruction.

Data Sources

MEDLINE, ProQuest Medical Library, and CINAHL

Study Selection

Six articles were chosen for inclusion in the systematic review. The authors narrowed 50 articles down to 6 by review of titles and abstracts. Included articles were randomized controlled trials written in English, published during 2000-2008, that evaluated the effects of OKC and CKC exercises on ACL deficient or reconstructed knees.

Data Extraction

Quality of the included studies was defined by the PEDro scale¹, which has been found to be reliable.²

Data Synthesis

Scores on the PEDro scale¹ ranged from 4-6/10. One article found positive significant effects with inclusion of OKC exercises in the rehabilitation program and another found significant benefits with combining OKC and CKC exercises. CKC exercises alone were not found by any studies to be superior to OKC exercises.

Conclusion

These studies reveal favorable results for utilization of both open and closed kinetic chain exercises for intervention with ACL deficient or reconstructed knees. However, further research needs to be completed.     

The Effects of Closed Kinetic Chain Exercises and Open Kinetic Chain Exercises Using Elastic Bands on Electromyographic Activity in Degenerative Gonarthritis

[Purpose] The purpose of this study was to examine the effects of closed kinetic chain exercises (CKCEs) and open kinetic chain exercises (OKCEs) with elastic bands on the electromyographic activity of patients with degenerative gonarthritis. [Subjects] The study subjects were 30 degenerative gonarthritis patients who were divided into a CKCE group (CKCEG, n=10), an OKCE group (OKCEG, n=10), and a control group (CG, n=10). [Methods] The CKCEG and the OKCEG performed exercises with elastic bands, and the CG took part in a quadriceps strengthening exercise. All three groups performed the exercises three times per week for four weeks. The electromyographic activities of the subjects’ vastus medialis (VM), rectus femoris (RF), vastus lateralis (VL), semitendinosus (ST), and biceps femoris (BF) muscles were measured and compared. [Results] Within-group comparisons revealed that the electromyographic activities of the VM, RF, VL, ST, and BF muscles increased significantly in the CKCEG. The OKCEG displayed significant increases in the electromyographic activity of the VM, RF, ST, and BF muscles, and the CG showed significant increases in the electromyographic activities of the RF, VL, ST, and BF muscles. In between-group comparisons after the intervention, the electromyographic activities of the VM, RF, and VL muscles of the CKCEG were significantly higher than those of the CG. The electromyographic activities of the VM, RF, and ST muscles of the OKCEG were significantly higher than those of the CG. [Conclusion] We consider CKCEs with elastic bands are an effective intervention for increasing the electromyographic activities of the VM, RF, VL, ST, and BF muscles of degenerative gonarthritis patients, and OKCEs with elastic bands are an effective intervention for increasing the electromyographic activities of the VM, RF, ST, and BF muscles of degenerative gonarthritis patients.     

Comparison of the Tibialis Anterior and Soleus Muscles Activities during the Sit-to-stand Movement with Hip Adduction and Hip Abduction in Elderly Females

[Purpose] The purpose of this study was to compare the activation of the tibialis anterior (TA) and soleus (SOL) muscles during the sit-to-stand (STS) task with hip adduction and hip abduction in elderly females. [Subjects] We recruited 16 healthy elderly females with no pain in the knee joint and no other orthopedic problems of the lower limbs. [Methods] The activities of the dominant lower extremity muscles were measured using a wireless electromyography (EMG) system. Subjects then performed a total of nine STS trials, including three trials each for hip adduction, hip abduction, and natural STS tasks. [Results] In the pre- thigh-off (TO) phase, the normalized EMG data of the TA muscle increased significantly when the STS task was performed with hip adduction compared with hip abduction. In the post-TO phase, the normalized EMG data of the TA muscle showed a significant increase during the STS task with hip adduction compared with hip abduction. Additionally, the normalized EMG data of the SOL muscle increased significantly when the STS task was performed with hip adduction compared with hip abduction. [Conclusion] Therefore, the STS movement with hip adduction poses a greater challenge for balance control, indicating that certain elderly individuals would have difficulty in executing an abrupt adjustment in their dynamic postural stability during the STS movement.Key words: Sit-to-stand, Hip adduction, Hip abduction     

扁平足楼梯行走的下肢表面肌电特性

目的 探究楼梯行走时扁平足下肢肌肉在运动控制中的表现。方法 2019年3月至6月,招募男性受试者20例,其中正常足10例,扁平足10例(均为左脚),运用Noraxon表面肌电系统采集平地行走、楼梯行走时左右胫骨前肌(TA)、内侧腓肠肌(MG)、外侧腓肠肌(LG)、股直肌(RF)、股二头肌(BF)表面肌电信号,分析平均幅值和积分肌电的变化。结果 上楼梯时,扁平足TA、RF、BF的平均幅值大于正常足(|t| > 2.461, P< 0.05);下楼梯时,扁平足MG的平均幅值大于正常足(t = -1.976, P< 0.05),BF的平均幅值小于正常足(t = 2.298, P< 0.05);与平地行走相比,扁平足上楼梯时TA、RF、BF的平均幅值增加(|t| > 2.257, P < 0.05),下楼梯时RF、BF的平均幅值增加(| t| > 2.630, P < 0.05)。上楼梯时,扁平足TA、MG、LG、RF和BF的积分肌电均大于正常足(| t| > 2.492, P < 0.01);下楼梯时,扁平足MG的积分肌电大于正常足( t = -5.271, P < 0.05),BF的积分肌电小于正常足( t = 2.685, P < 0.05);与平地行走相比,扁平足上楼梯时TA、MG、LG、BF的积分肌电均增大(| t| > 2.088, P < 0.05),下楼梯时TA、LG、RF的积分肌电均降低( t > 2.059, P < 0.05)。 结论 楼梯行走时,扁平足为控制关节过度外旋,肌肉出现补偿反应。     

Effects of trunk anterior tilt and knee joint flexion angle changes on muscle activity in the lower limb muscles

[Purpose] We examined the effects of trunk anterior tilt angle (TA) and knee flexion angle (KA) on lower limb muscle activity. [Participants and Methods] Twenty-eight healthy male participants (age, 24.7 ± 4.7 years) performed nine standing tasks with different TA and KA. The participants were instructed to remain still during each task. The nine standing tasks were randomly performed while measurements of muscle activity were obtained for seven muscles: gluteus maximus (GMAX), medial hamstrings (MH), lateral hamstrings (LH), rectus femoris (RF), vastus lateralis (VL), medial gastrocnemius (MG), and soleus (SOL). The activities of these muscles were normalized using isometric grade 3 of the manual muscle testing (isoMMT3). The intra-rater reliability for the mean values of the muscle activities measured with the isoMMT3 (intra-class correlation coefficient with 95% confidence interval) was confirmed using equation ICC (1,3). [Results] GMAX, MH, LH, RF, and MG were affected by both TA and KA, whereas VL was affected by KA, and SOL was affected by TA. [Conclusion] Our findings may facilitate a better understanding of the changes in muscle activity of the lower limb muscles due to differences in TA and KA.Key words: Electromyography, Muscle activation, Standing position     

表面肌电结合三维步态分析观察脑卒中患者步行支撑相期下肢肌肉激活时序的研究

目的 应用表面肌电技术结合三维步态分析研究卒中患者康复中步行支撑相期下肢肌肉激活时序的变化规律。 方法 采用分层随机化分组方式，按随机数字表法随机选取在院或门诊的Brunnstrom III期、IV期、V期脑卒中患者各20例，共60例患者分为III期组、IV期组及V期组。采用三维步态分析同步表面肌电图测试3组受试者步行支撑相期健患两侧下肢股直肌、股二头肌、胫前肌及腓肠肌各肌肉在步行支撑相期的激活开始时间和激活持续时间，比较各组受试者健、患两侧及组间对应下肢相关肌肉激活开始时间及持续时间（完整步态周期百分比）。 结果 III期组患侧股直肌激活开始时间显著迟于健侧，而患侧腓肠肌激活开始时间显著早于健侧，患侧股二头肌及腓肠肌激活持续时间均显著低于健侧，差异均有统计学意义（P<0.05）；IV期组患侧胫前肌、腓肠肌的激活开始时间均显著早于健侧，差异均有统计学意义（P<0.05）；V期组患侧胫前肌激活开始时间显著早于健侧，差异均有统计学意义（P<0.05）。IV期组患侧股直肌、患侧股二头肌激活开始时间分别为（-12.39±8.75）%和（-15.30±11.08）%，均显著早于III期组，差异均有统计学意义（P<0.05）；V期组健侧胫前肌和患侧腓肠肌的激活开始时间分别为（-5.01±7.51）%和（10.40±10.45）%，均显著迟于IV期组，差异均有统计学意义（P<0.05）；V期组健侧股直肌、健侧胫前肌、患侧腓肠肌激活开始时间分别为（-8.31±3.33）%、（-5.01±7.51）%和（10.40±10.45）%，显著迟于III期组，而其患侧股二头肌和胫前肌激活开始时间分别为（-12.7±11.88）%、（-25.11±14.60）%，显著早于III期组，差异均有统计学意义（P<0.05）；IV期组健侧股二头肌激活持续时间为（44.51±16.60）%，显著低于III期组，差异有统计学意义（P<0.05）；V期组健侧胫前肌激活持续时间为（46.32±13.77）%，显著低于IV期组，差异有统计学意义（P<0.05）；V期组患侧股直肌及健侧股直肌、股二头肌、胫前肌和腓肠肌的激活持续时间分别为（45.30±6.13）、（50.85±11.86）%、（37.74±18.24）%、（46.32±13.77）%和（46.72±25.06）%，均显著低于III期组，差异均有统计学意义（P<0.05）。 结论 不同恢复阶段的脑卒中患者在步行中健患两侧下肢肌肉的激活时序存在较大的差异，各阶段均存在患侧下肢部分肌肉的提前激活及健侧下肢部分肌肉的过度激活现象，随着下肢运动功能的恢复，其健侧下肢部分肌肉的过度激活逐渐得到改善。     

THE RELATIONSHIP BETWEEN LOWER EXTREMITY CLOSED KINETIC CHAIN STRENGTH & SAGITTAL PLANE LANDING KINEMATICS IN FEMALE ATHLETES

Background:

Female athletes continue to injure their anterior cruciate ligaments at a greater rate than males in comparable sports. During landing activities, females exhibit several different kinematic and kinetic traits when compared to their male counterparts including decreased knee flexion angles as well as decreased lower extremity (LE) strength. While open kinetic chain strength measures have not been related to landing kinematics, given the closer replication of movement patterns that occur during closed kinetic chain (CKC) activity, it is possible that lower extremity strength if measured in this fashion will be related to landing kinematics.

Purpose:

To determine if unilateral isometric CKC lower extremity (LE) strength was related to sagittal plane tibiofemoral kinematics during a single leg landing task in competitive female athletes. We hypothesized females who demonstrated lesser CKC LE strength would exhibit decreased sagittal plane angles during landing.

Methods:

20 competitive female athletes (age = 16.0 ± 1.8 yrs; height = 166.5 ± 8.3 cm; weight = 59.7 ± 10.2 kg) completed CKC LE strength testing followed by 5 unilateral drop landings on the dominant LE during one test session at an outpatient physical therapy clinic. Closed kinetic chain LE strength was measured on a computerized leg press with an integrated load cell while sagittal plane tibiofemoral kinematics were quantified with an electrogoniometer.

Results:

No significant relationships between absolute or normalized isometric CKC strength and sagittal plane landing kinematics were identified.

Conclusions:

Closed kinetic chain lower extremity isometric strength tested at 25 degrees of knee flexion is not related to sagittal plane landing kinematics in adolescent competitive female athletes.Levels of Evidence: Analytic, Observational     

Neuromuscular and architectural alterations of the vastus lateralis muscle in elderly patients with unilateral knee osteoarthritis]

AIM: The aim of this study was to determine the mechanisms involved in muscle weakness in elderly patients with unilateral knee osteoarthritis. SUBJECTS: We investigated 7 patients with unilateral knee osteoarthritis. METHOD: We measured knee position sense and isometric maximal voluntary contraction (MVC) of the knee extensors. Electromyographic (EMG) measurement of biceps femoris (BF), rectus femoris (RF), vastus lateralis (VL) and vastus medialis (VM) involved different levels of contraction (25, 50, 75 and 100% MVC). Neuromuscular efficiency of quadriceps was also calculated (MVC/EMG). Ultrasonography was used to investigate the VL architectural parameters at the median part of the VL for different levels of contraction (25, 50, and 75% MVC). All tests were performed on the osteoarthritic and healthy knees. RESULTS: The quadriceps MVC of the affected knee was reduced by 30%. The VL thickness of the affected knee was 10% smaller than that of the unaffected knee. VL activity seen on EMG did not differ between knees, but RF, VM and BF activity was greater in the unaffected than affected knee. Neuromuscular efficiency was higher (26%) in the unaffected knee. Knee position sense was reduced by 33% in the affected knee. CONCLUSION: Quadriceps weakness associated with knee osteoarthritis seems to be related to changes in muscle rather than pennation angle and changes in fascicule length.     

Effects of distally fixated versus nondistally fixated leg extensor resistance training on knee pain in the early period after anterior cruciate ligament reconstruction.

BACKGROUND AND PURPOSE: Nondistally fixated (ie, what is often referred to as "open kinetic chain" [OKC]) knee extensor resistance training appears to have lost favor for some forms of rehabilitation due partly to concerns that this exercise will irritate the extensor mechanism. In this randomized, single-blind clinical trial, nondistally fixated versus distally fixated (ie, often called "closed kinetic chain" [CKC]) leg extensor training were compared for their effects on knee pain. SUBJECTS: Forty-three patients recovering from anterior cruciate ligament (ACL) reconstruction surgery (34 male, 9 female; mean age=29 years, SD=7.9, range=16-54). METHODS: Knee pain was measured at 2 and 6 weeks after ACL reconstruction surgery using visual analog scales in a self-assessment questionnaire and during maximal isometric contractions of the knee extensors. Between test sessions, subjects trained 3 times per week using either OKC or CKC resistance of their knee and hip extensors as part of their physical therapy. RESULTS: No differences in knee pain were found between the treatment groups. DISCUSSION AND CONCLUSION: Open kinetic chain and CKC leg extensor training in the early period after ACL reconstruction surgery do not differ in their immediate effects on anterior knee pain. Based on these findings, further studies are needed using different exercise dosages and patient groups.     

Effect of exercise at light loads with manipulative resistance on infraspinatus,trapezius (upper fiber) and deltoid (middle fiber) muscle activities in shoulder joint elevation

[Purpose] To clarify rotator cuff muscular activity in the raised position of the closed kinetic chain (CKC) exercise. [Subjects] Twenty-nine cases were studied, 19 men and 10 women (average age 21.5 ±4.7 years old, average body weight 60.1 kg ±11.4). [Methods] To determine the effects of the closed kinetic chain exercise on the upper limb, we measured the surface EMG of the infraspinatus muscle, the trapezius (upper fiber) and the deltoid (middle fiber) with the arm elevated. [Results] Our results show that at an elevation angle of 150° in the scapular plane of the upper limb, with 5% body weight load, the EMG activities of the infraspinatus muscle are approximately 30% of maximum voluntary contraction (MVC). [Conclusion] The raised position of the CKC exercise is effective in physical therapy for functional recovery of the infraspinatus muscle.Key words: Shoulder joint, IEMG, CKC     

Electromyographic kinesiology of lower extremity muscles during slope walking

To investigate the phasic activity of the lower extremity muscles during up- and downslope walking, five muscles of ten healthy men were examined by telemetered electromyography (EMG). The muscles were the tibialis anterior (TA), gastrocnemius (Gc), rectus femoris (RF), semitendinosus (St) and gluteus maximus (GM). The inclination of the slope was 3, 6, 9 and 12 degrees. EMG of the muscles and the time factors of a walking cycle were recorded by a 12-channel polygraph simultaneously. In upslope walking, the duration of TA, St and GM activity was longer and that of RF activity was shorter than in level walking. The phasic pattern of Gc in upslope walking was the same as in level walking. In downslope, the duration of Gc and RF activity was longer than on the level. St showed biphasic activities. The phasic pattern of TA and GM was nearly the same as in level walking. The phasic activity of the muscles altered with an inclination over 6 degrees in upslope, and over 3 degrees in downslope. The findings indicate that the muscles stabilize the knee and ankle joint much more in slope walking than in level walking, and in slope walking they also exert themselves to elevate or lower the body weight.     

Electromyographic analysis of knee exercises in healthy subjects and in patients with knee pathologies

Little information exists about the intensity of contraction required from knee and hip musculature during common therapeutic exercises used for patient populations. This study, therefore, was designed to compare electromyographic data obtained from the vastus medialis, rectus femoris, gluteus medius, and biceps femoris muscles during maximally resisted straight-leg-raising (SLR) exercises with EMG data obtained from the same muscles during quadriceps femoris muscle setting (QS) exercises in healthy subjects and in patients with knee pathologies. Of the 30 participants in the study, 16 had a history of knee injury or surgery. All participants performed randomly ordered trials of the SLR and QS exercises while the EMG data were recorded from surface electrodes and normalized to values derived from maximal effort isometric contraction trials. An analysis of variance demonstrated significantly greater activity (p less than .05) of the vastus medialis, biceps femoris, and gluteus medius muscles during QS exercises than during SLR exercises. The rectus femoris muscle was significantly more active (p less than .05) during SLR exercises than during QS exercises. The study demonstrated remarkably different degrees of muscle activation between the SLR and QS exercises, indicating that the exercise selected will affect the therapeutic intention.     

Influence of angular velocity on vastus lateralis and rectus femoris oxygenation dynamics during knee extension exercises

The purpose of this study was to investigate whether changes in angular velocity would alter vastus lateralis (VL) and rectus femoris (RF) oxygenation status during maximal isokinetic knee extension exercises. Eleven recreationally active male participants randomly performed ten maximal knee extensions at 30, 60, 120 and 240° s(-1). Tissue oxygenation index (TOI) and total haemoglobin concentration ([tHb]) were acquired from the VL and RF muscles by means of near-infrared spectroscopy (NIRS). Breath-by-breath pulmonary oxygen consumption (VO(2p)) was recorded throughout the tests. Peak torque and VO(2p) significantly decreased as a function of velocity (P<0·05). Interestingly, RF and VL TOI significantly increased as a function of velocity (P<0·05), whereas [tHb] significantly decreased as a function of velocity (P<0·05). A greater number of muscle fibre recruited at slow velocity, where the torque and VO(2p) were the highest, might explain the lower VL and RF TOI observed herein. Furthermore, the increase in local blood flow (suggested by [tHb] changes) during isokinetic knee extension exercises performed at slow angular velocity might have been induced by a higher intramuscular pressure during the contraction phases as well as a greater microcirculatory vasodilatation during relaxation phases. Implementing slow-velocity isokinetic exercises in rehabilitation or other training programmes could delay the short-term anoxia generated by such exercises and result in muscle metabolism enhancement.     

Effects of Pelvic Belt on Hip Extensor Muscle EMG Activity during Prone Hip Extension in Females with Chronic Low Back Pain

[Purpose] This study assessed the effects of a pelvic belt (PB) on the electromyography (EMG) activity of the elector spinae (ES), gluteus maximus (GM), and biceps femoris (BF) in females with chronic low back pain (CLBP) during prone hip extension (PHE). [Subjects] Twenty female with CLBP were recruited. Surface EMG data were collected from the ES, GM, and BF muscles during a PHE task. [Results] The EMG activity in the ES bilaterally, and the right GM decreased significantly when a PB was applied compared with when a PB was not applied. [Conclusion] This suggests that a PB is effective for altering the activation pattern of the hip extensor muscles in females with CLBP during PHE.Key words: Chronic low back pain, Pelvic belt, Prone hip extension     

Comparison of Hip Stabilization Muscle Use during Neutral Sit to Stand and Sit to Stand Involving Isometric Hip Abduction in Elderly Females

[Purpose] The purpose of this study was to compare the activation of the gluteus medius (Gmed), rectus femoris (RF), and biceps femoris (BF) muscles during neutral (N) sit to stand (STS) and STS involving hip abduction (ABD) in elderly females. [Subjects] We recruited 16 healthy elderly females with no pain in the knee joint or any other orthopedic problems of the lower limbs. [Methods] The activities of the dominant lower extremity muscles were measured using a wireless electromyography (EMG) system. Subjects then undertook a total of six STS trials: three for neutral STS and three for STS involving hip abduction. [Results] In the pre-TO phase, activation of the RF muscle was significantly increased during hip ABD. In the post-TO phase during hip ABD, Gmed muscle activation was significantly increased, and RF muscle activation was significantly decreased. [Conclusion] This study suggests that STS involving hip ABD is more effective in decreasing Gmed activation and reducing RF effort in elderly females.Key words: Sit to stand, Hip abduction, Hip stabilization muscles