Evaluation of the Combined Application of Neuromuscular Electrical Stimulation and Volitional Contractions on Thigh Muscle Strength,Knee Pain,and Physical Performance in Women at Risk for Knee Osteoarthritis: A Randomized Controlled Trial

BackgroundKnee osteoarthritis (OA) is a leading cause of disability that is associated with quadriceps weakness. However, strengthening in people with or with risk factors for knee OA can be poorly tolerated.ObjectiveTo assess the efficacy of a 12-week low-load exercise program, using a hybrid training system (HTS) that uses the combination of neuromuscular electrical stimulation and volitional contractions, for improving thigh muscle strength, knee pain relief, and physical performance in women with or with risk factors for knee OA.DesignRandomized, single-blinded, controlled trial.SettingExercise training laboratory.ParticipantsForty-two women 44-85 years old with risk factors for knee OA.InterventionsParticipants randomized to 12 weeks of biweekly low-load resistance training with the HTS or on an isokinetic dynamometer (control).OutcomesMaximum isokinetic knee extensor torque. Secondary measures included maximum isokinetic knee flexor torque, knee pain (Knee Injury and Osteoarthritis Outcome Score), and timed 20-m walk and chair stand tests.ResultsThe HTS and control treatments resulted in muscle strengthening, decreased knee pain, and improved physical performance. HTS group quadriceps and hamstring strength increased by 0.06 ± 0.04 Nm/kg (P > .05) and 0.05 ± 0.02 Nm/kg (P = .02), respectively. Control group quadriceps and hamstring strength increased by 0.03 ± 0.04 Nm/kg (P > .05) and 0.06 ± 0.02 Nm/kg (P = .009), respectively. Knee pain decreased by 11.9 ± 11.5 points (P < .001) for the HTS group and 14.1 ± 15.4 points (P = .001) for the control group. The 20-m walk time decreased by 1.60 ± 2.04 seconds (P = .005) and 0.95 ± 1.2 seconds (P = .004), and chair stand time decreased by 4.8 ± 10.0 seconds (P > .05) and 1.9 ± 4.7 seconds (P > .05) in the HTS and control groups, respectively. These results did not differ statistically between the HTS and control groups.ConclusionsThese results suggest the HTS is effective for alleviating pain and improving physical performance in women with risk factors for knee OA. However, the HTS does not appear to be superior to low-load resistance training for improving muscle strength, pain relief, or physical function.Clinical trial registration number: NCT02802878.Level of EvidenceI     

限弧等速肌力训练对于髌股关节炎髌骨轨迹的影响

目的:探讨不同限弧等速肌力训练对髌股关节炎患者髌骨轨迹的影响。方法:诊断为髌股关节炎患者60例,按接诊顺序分为A组(0°~30°)、B组(30°~60°)和C组(60°~90°)不同角度限弧运动训练组,每组各20例,采用德国ISOMED 2000等速肌力训练系统按分组对患者膝关节周围肌肉进行4周的限弧等速肌力训练。训练前、后拍摄膝关节负重正侧位及屈膝45°轴位片,测量髌骨轨迹参数(即髌股指数、外侧髌股角、髌骨合适角);记录每个膝关节的等速肌力测定值,即峰力矩(PT)、总功(TW)及平均功率(AP);采用西安大略和麦克马斯特大学骨关节炎指数(WOMAC)(包括疼痛、僵硬、日常功能)评定膝关节功能。结果:训练4周后,A组髌股指数、髌骨合适角较训练前明显降低,外侧髌股角较训练前明显提高(P<0.05);A、B、C组峰力矩PT、总功TW及平均功率AP值均较训练前明显提高(P<0.05);WOMAC评分比较,A组疼痛、日常功能评分较训练前明显降低(P<0.05)。训练后,髌骨轨迹参数比较:髌股指数、髌骨合适角A组明显低于B、C组(P<0.05),外侧髌股角明显高于B、C组(P<0005);等速肌力测定值比较:A组PT值明显高于B、C组(P<0.05);WOMAC评分比较:疼痛评分A组明显低于B、C组(P<0.05)。B组与C组间各评分差异无统计学意义。结论:膝关节屈曲范围0°~30°的股四头肌等速训练可有效改善髌股关节炎髌骨轨迹,提高膝关节功能。     

The effect of progressive resistance training on leg strength,aerobic capacity and functional tasks of daily living in persons with Down syndrome

Purpose.?The purpose of this study was to examine the effect of progressive resistance training on leg strength, aerobic capacity and physical function in persons with Down syndrome (DS).

Method.?Thirty persons with DS (age 28 SD 8 years) were assigned to an intervention or control group. The intervention group performed resistance training 2 days per week for 10 weeks. Participants performed tests to measure isometric and isokinetic knee extensor and flexor peak torque, peak aerobic capacity and timed performance on chair rise, walking and stair ascent and descent.

Result.?Persons with DS receiving the intervention significantly increased their isokinetic knee extensor and flexor peak torque [[Absolute change (post minus pre-value) was 17.0 SD 29.6 and 12.6 SD 18.9 N m, respectively]] and isometric knee extensor peak torque at angles of 45° (2.9 SD 23.2 N m), 60° (3.0 SD 22.9 N m) and 75° (14.2 SD 30.0 N m). These changes were significantly greater than in the control group. In addition, the time to ascend (?0.3 SD 0.8?s) and descend (?0.6 SD 0.9?s) stairs significantly decreased in the intervention group compared to the control group.

Conclusion.?These findings show that progressive resistance training is an effective intervention for persons with DS to improve leg strength and stair-climbing ability.     

Contribution of components of the quadriceps femoris muscle for producing external torque in patients with patellofemoral pain syndrome

IntroductionDifferent muscular activities of the quadriceps components for producing necessary torque may change in patients with patellofemoral pain syndrome (PFPS). The aim of the current study, therefore, was to assess the contribution of each component of the quadriceps femoris muscle for producing external torque in patients with PFPS.MethodTwelve females with PFPS (24.7 ± 2.3 years) and twelve healthy matched females (25.4 ± 2.4 years) performed three consecutive knee flexion and extension movements with maximum effort at 45°/s and 300°/s using a Biodex system 3 dynamometer. Simultaneously, electromyographic (EMG) activities of the vastus medialis oblique (VMO), RF (rectus femoris) and vastus lateralis (VL) muscles were recorded using a DataLog instrument. Standard multiple regressions were used to assess the ability of EMG activities of the VMO, RF and VL muscles to predict normalized quadriceps femoris isokinetic concentric and eccentric torques at 45°/s and 300°/s in the normal and patient groups.ResultsIn the normal group, the VL and the VMO were the good predictors of quadriceps concentric torque at 45°/s and 300°/s, respectively. The VL and the RF were the good predictors of quadriceps eccentric torque at 300°/s in the patient group. No other conditions showed a considerable prediction for quadriceps torque in the normal or patient group.ConclusionFemales with PFPS differ with normal females in terms of the contribution of each component of the quadriceps femoris for producing external torque. Training the VMO for concentric contraction at both high and low velocities should be included in the management of the patients with PFPS.     

等速向心肌力训练对膝关节骨性关节炎患者关节功能水平的影响

目的:研究腿部肌群等速向心肌力训练对提高膝关节骨性关节炎患者关节功能水平的作用。方法:将膝关节骨性关节炎患者100例(168膝)随机分为两组,对照组50例(85膝),进行推髌骨、股四头肌训练及楔形垫行走训练等常规康复治疗;等速组50例(83膝),在常规康复治疗的基础上进行患腿肌群等速运动训练。所有患者均在治疗前和治疗后8周时接受等速肌力测试及采用Lysholm膝关节功能评分作为康复疗效判定标准。结果:经过8周的系统康复治疗,等速组与对照组患者的屈、伸肌峰力矩(PT)、总功量(TW)、平均功率(AP)和伸屈肌单次最大作功量(MRTW)均较前有改善,等速组改善较对照组更明显(P<0.01)。两组的患者的Lysholm评分均较前有改善,等速组Lysholm评分较对照组进步明显(P<0.01)。结论:等速向心肌力训练明显提高膝关节骨性关节炎膝部肌群力量,改善关节功能。     

Effect of magnetic knee wrap on quadriceps strength in patients with symptomatic knee osteoarthritis

Chen C-Y, Chen C-L, Hsu SC-C, Chou S-W, Wang K-C. Effect of magnetic knee wrap on quadriceps strength in patients with symptomatic knee osteoarthritis.

Objective

To determine the effects of magnetic knee wrap on isokinetic quadriceps strength in patients with painful knee osteoarthritis (OA).

Design

Randomized, double-blinded, placebo-controlled and before-after trial.

Setting

Rehabilitation clinic in a tertiary hospital.

Participants

Eligible patients (N=50) (mean age ± SD, 66.0±8.6y) with mild to moderate knee OA were recruited from the outpatient department and 37 (74%) completed the trial. Only 3 (6%) withdrew due to study-related adverse effects.

Interventions

Wearing the active (n=24) or sham (n=26) magnetic knee wrap for 12 weeks.

Main Outcome Measures

The primary outcome measure was isokinetic quadriceps strength. Secondary outcome measures included the Health Assessment Questionnaire Disability Index (HAQ-DI) and the Health Assessment Questionnaire (HAQ) Pain Scale.

Results

Using intention-to-treat analyses, the peak isokinetic quadriceps strength increased significantly in the treated leg at 30°/s (P=.007) and 60°/s (P=.022) after wearing the magnetic knee wrap. Compared with baseline, the median strength increase for the treated leg in the study group significantly exceeded that in the control group at week 4 (.05Nm/kg vs −.09Nm/kg at 60°/s, P=.038) and week 12 (30°/s, .09Nm/kg vs .04Nm/kg, P=.044; 60°/s, .17Nm/kg vs .02Nm/kg, P=.031). The HAQ-DI and HAQ Pain Scales improved significantly in both groups. Compared with baseline, the improvement at week 12 in terms of the HAQ-DI in the study group significantly exceeded that in the control group.

Conclusions

Magnetic knee wrap may significantly facilitate isokinetic quadriceps strength in patients with mild to moderate knee OA.     

推拿结合等速肌力训练治疗膝关节骨性关节炎临床疗效研究

目的:观察推拿治疗结合等速肌力训练对膝关节骨性关节炎的治疗效果。方法:从膝关节骨性关节炎(KOA)患者中随机选取60例作为观察对象,60例患者随机分为推拿结合等速治疗组(试验组)和单纯推拿治疗组(对照组)。分别将两组治疗前后的膝关节西安大略和麦克马斯特大学骨关节炎指数(WOMAC)、等速屈伸肌力测试对比分析。结果:两组治疗后膝关节WOMAC评分均较治疗前有显著改善(P0.01),其中推拿结合等速组膝关节WOMAC评分由(62.93±16.17)降为(26.20±12.68),改善较单纯推拿组更为显著(P0.01)。两组治疗干预前等速肌力测试各指标比较没有显著性差异。经过8周治疗后推拿加等速训练组膝关节伸肌峰力矩、峰力矩/体重、达峰时间、平均功率,膝关节屈肌峰力矩、达峰时间与本组治疗前比较明显改善,差异有显著性(P0.01);膝关节伸肌平均功率与本组治疗前比较有改善,差异有显著性(P0.05);推拿加等速训练组膝关节伸肌峰力矩、峰力矩/体重、达峰时间、膝关节屈肌达峰时间、屈肌/伸肌比单纯推拿组治疗后改善明显,差异有显著性(P0.05);推拿加等速训练组膝关节屈肌峰力矩与单纯推拿组治疗后比较提高明显,差异有显著性(P0.01)。结论:推拿结合等速肌力训练可以提高KOA患者膝关节屈伸肌肉力量,对于KOA的治疗具有良好的临床疗效,且明显优于单纯推拿治疗。     

膝骨关节炎患者股四头肌功能水平及髋关节步态运动学特征分析

目的:观察中老年膝骨关节炎(KOA)患者股四头肌功能水平及步行过程中髋关节的运动学特征。方法:选取18例KOA患者为KOA组,8例无KOA者为对照组,2组的年龄、身高、体重和身体质量指数(BMI值)相匹配。2组受试者均进行等速肌力测试、无线表面肌电测试及步态测试,测试及比较2组股四头肌峰力矩(PT值)、股内侧肌(VM)、股外侧肌(VL)和股直肌(RF)的积分肌电值(iEMG)、均方根值(RMS)、平均功率频率(MPF)及峰值髋内收、外展角度等和步行中髋关节的运动学特征,将股四头肌肌力与髋关节运动学特征进行相关性分析。结果:KOA组股四头肌等长和等速运动时PT值较对照组显著下降(P<0.01),VL在60°/s等速收缩时表面肌电信号RMS值显著高于对照组(P<0.05),RF在180°/s等速收缩时表面肌电信号RMS值显著高于对照组(P<0.01),步行时峰值髋关节内收及外展角度显著低于对照组(P<0.05),股四头肌肌力与髋关节运动学特征无相关。结论:KOA组较对照组股四头肌肌力显著降低,活动时神经支配效率显著下降,且步行过程中峰值髋内收、外展角度显著减少,股四...     

Quadriceps-strengthening exercise and quadriceps and knee biomechanics during walking in knee osteoarthritis: A two-centre randomized controlled trial

ObjectiveTo assess the effect of quadriceps strengthening on quadriceps muscle force, power, and work and tibio-femoral compressive loads during walking in adults with knee osteoarthritis.MethodsStudy design: Two-center, randomized, controlled trial. Intervention: Patients with knee osteoarthritis were randomly allocated to quadriceps strengthening program (3 times weekly) or no attention control group. Main outcome measures: Primary outcome was change from baseline in peak quadriceps force during walking at 12 weeks. Secondary outcomes included quadriceps power and work, knee compression forces during walking estimated with musculoskeletal modeling, muscle strength and pain and function. Outcomes were measured at baseline and 12 weeks.Results30 patients were randomized to receive either training (n = 15) or no attention (n = 15). At follow-up, there were no statistical differences between groups for maximum quadriceps force, quadriceps positive power, negative work, and positive work, and knee compressive force. Maximum negative quadriceps power in early stance was statistically significantly increased 36% in the training group compared to the control group which was most likely partially a response to faster walking velocity at follow-up. Muscle strength and patient reported pain and function were improved in the training group compared to the control group.ConclusionsQuadriceps strength training leads to increased muscle strength and improved symptomatic and functional outcomes but does not change quadriceps or knee joint biomechanics during walking. The biomechanical mechanism of improved health with strength training in knee osteoarthritis patients remains unknown.ClinicalTrials.gov Identifier: NCT01538407.     

Selective hypertrophy of the quadriceps musculature after 14 weeks of isokinetic and conventional resistance training

One of the fundamental adaptations observed with resistance training (RT) is muscle hypertrophy. Conventional and isokinetic machines provide different forms of mechanical stress, and it is possible that these two training modes could promote differing degrees of hypertrophic adaptations. There is a lack of data comparing the selective hypertrophy of the quadriceps musculature after training with a conventional knee extension machine versus an isokinetic machine. The purpose of this study was to evaluate the selective hypertrophy of the quadriceps musculature and knee extension maximal isometric torque after 14 weeks of conventional versus isokinetic RT. Thirty-five men were assigned to three groups: control group and training groups (conventional and isokinetic) performed three sets of unilateral knee extensions per session with a progressive loading scheme twice a week. Prior to and following the intervention, maximal isometric knee extensor torque was measured using an isokinetic dynamometer, and muscle thickness (MT) of quadriceps femoris muscles was assessed via ultrasound. The results indicated non-uniform changes in MT between the muscles that comprise the quadriceps femoris group. For the conventional group, significantly greater increases in rectus femoris thickness were evident versus all other quadriceps muscles (14%). For the isokinetic group, increases in RF thickness (11%) were significantly greater in comparison with the vastus intermedius only. Although the muscle thickness did not increase for all the quadriceps femoris muscles, the relative rectus femoris adaptation suggested a selective hypertrophy favouring this portion.     

Efficacy of isokinetic exercise on joint position sense and muscle strength in patellofemoral pain syndrome

OBJECTIVE: The objective of this study was to demonstrate the impairment of knee joint position sense in individuals with patellofemoral pain syndrome and investigate the effects of isokinetic exercise on knee joint position sense and muscle strength. DESIGN: A total of 24 male patients complaining of anterior knee pain caused by overexertion and 24 male healthy individuals without symptoms were included for this investigation. Isokinetic exercise protocol was carried out at angular velocities of 60 degrees/sec and 180 degrees/sec. These sessions were repeated three times per week and lasted for 6 wks. At the beginning and after 6 wks of knee passive joint position sense, quadriceps and hamstring muscle strength and pain assessments were performed. RESULTS: After the isokinetic exercise, flexion peak torque (P < 0.05), extension peak torque (P < 0.01), flexion total work (P < 0.001), extension total work (P < 0.001), passive reproduction of knee joint position sense for 40 degrees of flexion (P < 0.05) and 50 degrees of extension (P < 0.01), and pain score (P < 0.001) improved significantly in the patellofemoral pain syndrome group. CONCLUSION: Isokinetic exercises have positive effects on passive position sense of knee joints, increasing the muscular strength and work capacity. These findings show that using the present isokinetic exercise in rehabilitation protocols of patients with patellofemoral pain syndrome not only improves the knee joint stabilization but also the proprioceptive acuity.     

A comparison of eccentric isokinetic torque production and velocity of knee flexion angle during step down in patellofemoral pain syndrome patients and unaffected subjects

OBJECTIVE: To determine knee angular velocity changes during stair descent and slow velocity eccentric isokinetic quadriceps contraction, in normal controls and patellofemoral pain syndrome patients. DESIGN: Isokinetic and kinematic analysis of the performance of patellofemoral pain syndrome patients and matched normal controls. BACKGROUND: In the presence of increased patellofemoral joint stresses, patellofemoral pain syndrome patients have been shown to adopt compensatory strategies to minimise joint loading and therefore pain. One of the compensatory strategies reported, is that of the break phenomena, which results in a change quadriceps torque production. METHODS: Twenty female patients with patellofemoral pain syndrome and 20 asymptomatic matched controls participated in the study. All subjects had their isokinetic eccentric and concentric quadriceps torque assessed at 30 degrees/second and 2-dimensional video data taken when descending from a step. Variations in knee angular velocity and torque curves were then identified. RESULTS: None of the subjects demonstrated a break on isokinetic concentric quadriceps contraction. Of the patellofemoral pain syndrome patients, 50% (10 out of 20) had a break in eccentric torque curve on testing, compared with 15% (3 out of 20) of the controls. Abnormal curve perturbation was demonstrated to occur in none of the controls isokinetically, but 20% (4 out 20) of the patellofemoral pain syndrome patients had perturbations in their torque curves. On stair decent a break was seen in 60% (12 out of 20) of the patellofemoral pain syndrome patients and 15% (3 out of 20) of the control subjects on analysis of the knee angular velocity. Twenty percent (4 out of 20) of the patellofemoral pain syndrome patients and 10% (2 out of 20) of the controls had abnormal curve perturbation on analysis of their stair descent. CONCLUSIONS: The implications are that there appears to be a relationship between patellofemoral pain syndrome and control of eccentric quadriceps contraction. This relationship is possibly related to joint and soft tissue loading not just the degree of pain, with the break being a saving reflex to prevent further stress. RELEVANCE: Exercise to rehabilitate the quadriceps in patellofemoral pain syndrome should be chosen with regard to joint loading and range of movement as well as velocity of contraction, in order to facilitate quadriceps activation as opposed to inhibiting it.     

Osteoarthritis of the knee: isokinetic quadriceps exercise versus an educational intervention.

OBJECTIVE: To evaluate the effects of isokinetic exercise versus a program of patient education on pain and function in older persons with knee osteoarthritis. DESIGN: A randomized, comparative clinical trial, with interventions lasting 8 weeks and evaluations of 12 weeks. SETTING: An outpatient Veterans Affairs Medical Center clinic and an affiliated university hospital. PATIENTS: One hundred thirteen men and women between 50 and 80 years old with diagnosed osteoarthritis of the knee; 98 completed the entire assigned treatment. INTERVENTION: Patients received either a regimen of isokinetic exercise of the quadriceps muscle three times weekly over 8 weeks or a series of 4 discussions and lectures led by health care professionals. MAIN OUTCOME MEASURES: Variables studied for change were isokinetic and isometric quadriceps strength, pain and function determined by categorical and visual analog scales, and overall status using physician and patient global evaluations by the Arthritis Impact Scale, version 2, Western Ontario McMaster's Arthritis Index, and Medical Outcome Study Short Form 36. RESULTS: Both treatment groups showed significant strength gains (p < .05), which occurred over a wider velocity spectrum for the exercise group. Exercised patients also had improved pain scores for more of the variables measured than those receiving education. Both groups had positive functional outcomes and slightly improved measures of overall status. CONCLUSIONS: Isokinetic exercise is an effective and well-tolerated treatment for knee osteoarthritis, but a much less costly education program also showed some benefits.     

超声波结合股四头肌肌力训练治疗老年膝关节骨关节炎

目的探讨超声波结合股四头肌肌力增强训练对老年膝关节骨关节炎的疗效. 方法将76例老年膝关节骨关节炎患者随机分为实验组和对照组,每组38例.实验组采用超声波结合股四头肌肌力训练,对照组应用综合物理疗法治疗.对患膝治疗前和治疗4周后的日常活动(ADL)能力、疼痛程度及伸直位最大负荷量进行评定. 结果实验组在缓解疼痛、改善膝关节ADL能力方面略优于对照组(P>0.05),但其股四头肌肌力较治疗前及对照组明显增强(P<0.01). 结论超声波结合股四头肌肌力强化训练治疗老年膝关节骨关节炎,可获得较满意的治疗结果.     

Relationship between knee alignment and the electromyographic activity of quadriceps muscles in patients with knee osteoarthritis

[Purpose] We evaluated the relationship between knee alignment and the electromyographic (EMG) activity of the vastus medialis (VM) to the vastus lateralis (VL) muscles in patients with knee osteoarthritis (OA) in a cross-sectional study. [Subjects and Methods] Forty subjects with knee OA were assessed by anatomic radiographic knee alignment and the VM/VL ratio was calculated. Surface EMG from both the VM and VL muscles were evaluated during maximal isometric contraction at 60° knee flexion. Simultaneously, peak quadriceps torque was assessed using an isokinetic dynamometer. Subjects were categorized into low, moderate, and high varus groups according to knee malalignment. The peak quadriceps torque and VM/VL ratio across groups, and their relationships with varus malalignment were analyzed. [Results] All subjects had medial compartment OA and the VM/VL ratio of all subjects was 1.31 ± 0.28 (mean ± SD). There were no significant differences in the peak quadriceps torque or VM/VL ratios across the groups nor were there any significant relationships with varus malalignment. [Conclusion] The VM/VL ratio and peak quadriceps torque were not associated with the severity of knee varus malalignment.Key words: Malalignment, Knee, Quadriceps     

膝骨关节炎患者膝屈伸肌群等速肌力及其与功能的相关性

目的观察膝关节骨关节炎(KOA)患者膝屈伸肌群等速肌力变化及其与膝关节功能的关系。方法23 例双侧KOA患者及14 名正常人进行膝屈伸肌等速肌力检查、五次坐-起试验(FTSST)、静态平衡测试、步态分析。KOA组还完成疼痛视觉模拟评分(VAS)及WOMAC骨关节炎指数评定。结果KOA组伸肌及屈肌峰力矩、峰力矩均值、平均功率、单次最佳做功及总功主患侧均小于对侧(P<0.05);峰力矩屈肌/伸肌(H/Q)百分比主患侧大于对侧(P<0.05)。组间比较,伸肌所有观察指标、屈肌平均功率KOA组均小于正常对照组(P<0.05);峰力矩H/Q 百分比KOA组大于正常对照组(P<0.05)。KOA组伸肌等速肌力峰力矩与FTSST、步行速度、步行距离、跌倒指数、VAS 评分、WOMAC-疼痛评分之间存在相关性(P<0.05),屈肌等速肌力峰力矩与FTSST、步态参数、跌倒指数、VAS评分、WOMAC评分之间无明显相关性(P>0.05)。结论KOA患者伸肌及屈肌等速肌力主患侧较对侧减弱,伸肌等速肌力较正常人减弱,膝伸屈肌肌力变化不同步。KOA患者伸肌等速肌力峰力矩与膝关节疼痛、功能之间存在相关性。     

Electric muscle stimulation of the quadriceps in the treatment of patellofemoral pain

OBJECTIVE: To compare a commercially available electric muscle stimulation regimen with a novel form of stimulation for the rehabilitation of the quadriceps muscle, in patients with patellofemoral pain syndrome. DESIGN: Double-blinded randomized trial with a parallel control group and stratified randomization. SETTING: Home-based rehabilitation program assessed in research center. PARTICIPANTS: Eighty patients (47 women, 33 men) with patellofemoral pain syndrome. INTERVENTIONS: One group (EMPI) received 1 uniform constant frequency component of 35Hz. The other (EXPER) group received an experimental form of stimulation that contained 5 simultaneously delivered frequency components of 125, 83, 50, 2.5, and 2Hz. Stimulation was applied to the quadriceps muscles of the affected leg for 1 hour daily for 6 weeks, a total of 42 treatments. MAIN OUTCOME MEASURES: Lower-limb isometric and isokinetic torque, quadriceps fatigue, knee flexion, patellar pain, a step test, quadriceps cross-sectional area, and Kujala patellofemoral score for pain before and after treatment. RESULTS: Seventy-four patients (43 women, 31 men) completed the trial. Patients in both groups showed significant improvements in all outcomes (P<.05). No significant differences existed between the 2 stimulators in any outcome (P>.05) except for quadriceps cross-sectional area (P=.023). CONCLUSIONS: One form of stimulation was just as efficacious as the other in improving subjective and objective measures.     

Effects of combined application of progressive resistance training and Russian electrical stimulation on quadriceps femoris muscle strength in elderly women with knee osteoarthritis

[Purpose] The aim of this study was to investigate the effects of combined application of progressive resistance training and Russian electrical stimulation on quadriceps femoris muscle strength in elderly women with osteoarthritis of the knee. [Subjects] Thirty women over 65 years of age diagnosed with knee osteoarthritis participated in the present study. The subjects were randomly assigned to a control group (n=10), a progressive resistance training group (n=10), or a Russian electrical stimulation group (n=10). [Methods] Each group was treated 3 times weekly for 8 weeks, and each session lasted 45 minutes. Muscle strength was assessed by measuring the peak torque of the quadriceps femoris muscle. Outcome measurements were performed at baseline and at the fourth and eighth weeks of the treatment period. [Results] All groups showed significant intragroup differences in the quadriceps femoris muscle peak torque after the treatment intervention. There were significant intergroup differences between the Russian electrical stimulation group and the other groups. [Conclusion] The results of this study suggest that combined application of progressive resistance training and Russian electrical stimulation can be effective in strengthening the quadriceps femoris muscle in elderly women with knee osteoarthritis.Key words: Knee osteoarthritis, Progressive resistance training, Russian electrical stimulation     

Isokinetic testing of quadriceps function in COPD: feasibility,responsiveness, and minimal important differences in patients undergoing pulmonary rehabilitation

BackgroundIsokinetic testing of peripheral muscle function is valid and reliable in patients with chronic obstructive pulmonary disease (COPD).ObjectiveTo evaluate whether and to what extent isokinetic testing of quadriceps function meets pre-defined test criteria in patients with COPD; to determine the response to pulmonary rehabilitation (PR), and to calculate minimal important differences (MIDs) of isokinetic quadriceps function.MethodsRetrospective analysis of 2033 patients with COPD (age: 65±9 years, body mass index: 26±6 kg/m², FEV₁: 49±22% predicted) who followed a comprehensive PR program. Pre and post PR isokinetic quadriceps function was assessed with 30 maximal extension-flexion contractions at an angular speed of 90°/s on a computerized dynamometer. The chosen anchors were 6-min walk test and COPD assessment test.ResultsPre PR, 27% of the patients performed the isokinetic test incorrectly. In male and female patients with a correct pre and post PR isokinetic test, peak torque (Δ=10±13 Nm or 9% and Δ=7±9 Nm or 10%, respectively) and total work (Δ=263±270 J or 14% and Δ=198±190 J or 15%, respectively) improved significantly. There was no change in work fatigue index following PR. Using distribution-based calculations, MID estimates for peak torque and total work ranged between 6–7 Nm and 97–135 J in males and between 4–5 Nm and 62–99 J in females.ConclusionsBased on the current test criteria, three in four patients with COPD performed the isokinetic quadriceps test correctly during baseline PR assessment. Furthermore, peak torque and total work, but not work fatigue index, were responsive to PR and sex-specific MIDs were established.