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.     

Isometric and isokinetic measurement of hamstring and quadriceps strength.

This study evaluates quadriceps strength at varying movement velocities in a group of healthy subjects. Specific objectives included (1) investigating the effect of angular velocity on peak torque (PT) (2) investigating the effect of angular velocity on joint angle at peak torque (JAPT) and (3) evaluating whether the use of a relatively new isokinetic testing device yields new insights to previously accepted relationships between angular velocity and PT or JAPT. Twenty healthy subjects were tested for isometric and isokinetic knee extension and flexion strength on a LIDO Active Isokinetic Rehabilitation System at velocities of 0 degrees, 60 degrees, 120 degrees, and 180 degrees/sec. Isometric PT (0 degrees/sec) was found to be highly correlated with isokinetic PT for both extensors and flexors at all velocities (r = .88-.93, p less than .01). PT declined significantly as angular velocity increased for both extension (p less than .01) and flexion (p less than .05). A relationship between isometric and isokinetic JAPT was significant for extension only at 60 degrees and 180 degrees/sec (r = .48-.52, p less than .05). These results indicate that knee isometric and isokinetic PT as measured on the LIDO Active system are highly related for both extension and flexion. PT declined as isokinetic angular velocity increased. Isometric and isokinetic JAPT are significantly related only for extension.     

Concentric versus combined concentric-eccentric isokinetic training: effects on functional capacity and symptoms in patients with osteoarthrosis of the knee

OBJECTIVE: To compare the effects of concentric and coupled concentric-eccentric isokinetic resistance training on functional capacity and symptoms of patients with osteoarthrosis (OA) of both knees. DESIGN: Repeated measures. SETTING: A university exercise physiology laboratory. PARTICIPANTS: Twenty-three volunteers, ages 41 to 75 years. Patients were randomly assigned to 3 groups: concentric (CON, n = 9), concentric-eccentric (CON-ECC, n = 8), and nontreatment (NONTX, n = 6). INTERVENTIONS: The CON group performed 12 concentric contractions of each knee extensor and flexor muscles; the CON-ECC group performed 6 concentric and 6 eccentric contractions of each knee muscle group by using a spectrum of angular velocities ranging from 30 degrees/s to 180 degrees/s with 30 degrees/s intervals, for both sides, 3 days a week for 8 weeks. MAIN OUTCOME MEASURES: Functional capacity (rising from a chair, walking, stair climbing and descending) and pain during rest and activities, peak torque, and cross-sectional area (CSA) of knee muscle groups of subjects were tested before and after training. RESULTS: Both training groups showed marked decreases (P <.001) in pain scores and increases (P <.001) in functional capacity together with increases (P <.05--.01) in peak torque and CSA of knee muscles. However, the NONTX group did not display these marked changes after the 8-week period. The results also indicated that concentric-eccentric training has a greater influence on functional capacity, especially stair climbing and descending, than that of concentric training when compared with NONTX group; however, the improvements in pain measurements were better in the CON group compared with the CON-ECC group after the training. CONCLUSIONS: The results suggest that with the isokinetic resistance training used in this study, it is possible to improve functional capacity and decrease pain in patients with OA of the knee. The results also showed that extensive training involving a high number of repetitions and eccentric contractions was safe, effective, and well tolerated for the patients with knee OA.     

Relationship of muscle strength for knee extension to walking capacity in patients with spastic hemiparesis

Muscle strength for knee extension, both isokinetic and isometric, and walking capacity, maximum velocity and walking rate, were examined in 11 post-stroke hemiparetic patients. The degree of spasticity of the affected lower extremity was not related to the isokinetic and isometric torques, or to the walking capacity. Although both the isokinetic and isometric torques decreased on the affected side compared to the non-affected side, the rate of decrease was remarkable in isokinetic torque at fast velocities. The walking capacity was well correlated with isokinetic torque of the affected side at fast velocities but not isometric torques. These results suggest that reduction of muscle strength at rapid movements is an essential feature of spastic paresis and is primary cause of motor disabilities such as impaired locomotor function.     

Isokinetic knee flexion and extension torque in the upright sitting and semireclined sitting positions

We undertook this study to determine whether the isokinetic knee extension and flexion torque generated by 14 young healthy women was greater in the upright sitting test position or in the semireclined sitting test position. Testing was performed at 60 degrees/sec. Knee extension torque did not differ significantly between the two test positions. The subjects, however, did produce significantly greater knee flexion torque when upright compared with when semireclined (p less than .001). Therapists should recognize that the results of testing isokinetic knee extension in the two positions may be similar, but that the results of testing isokinetic knee flexion may be significantly different.     

Effect of resisted knee flexion on knee extension torque

We tested the principle of "reversal of antagonists" by measuring the effect of resisted knee flexion on subsequent peak knee extension torque at velocities of 60 degrees/sec and 120 degrees/sec using an isokinetic dynamometer. We determined peak knee extension torques from torque curves produced during knee extension that was performed reciprocally with either passive or maximum voluntary resisted knee flexion. We used a crossover design so that all 18 healthy adult subjects performed knee extension reciprocally with both passive and resisted knee flexion. Paired means t tests revealed no statistically significant difference between the peak knee extension torques produced under the two knee flexion conditions either at 60 degrees/sec or 120 degrees/sec. We, therefore, concluded that resisted knee flexion does not augment peak knee extension torque under our conditions of testing. The concept of reversal of antagonists was not supported. Antagonistic muscle functioning, therefore, may be irrelevant to agonist isokinetic testing and training in neurologically healthy persons.     

Knee flexor/extensor strength ratio in follow-up of acute knee distortion injuries

This study evaluated the peak torque and total work hamstring/quadriceps (HQ) ratios of 77 knees with a previous grade I distortion injury to find the possible relationship between different HQ ratios and long-term outcome. For measurement of quadriceps and hamstrings strengths, the CYBEX II isokinetic dynamometer was used. Peak torque values were recorded at low (60 degrees/sec) and high (180 degrees/sec) speeds of isokinetic movement, and the maximal isometric extension and flexion outputs were measured with the knee at a 60 degree angle. Three standardized knee scoring scales were used to determine the subjective, functional, clinical, and radiologic outcome of the injured knees. In every test, great intersubject variation of the HQ ratio was observed, even in healthy knees (range 19% to 148%). Follow-up scores of the groups with low (less than 50%), optimal (50% to 80%), or high (greater than 80%) HQ ratios of the injured knees did not differ significantly from each other. However, in every test the scores were significantly (p less than 0.001 to less than 0.0001) better in patients whose injured knee HQ ratio was nearly identical (less than or equal to 15%) rather than clearly different from (greater than 15%) the uninjured knee. These findings confirm our previous observation that the HQ ratio is an idiosyncratic parameter. Any general recommendation about optimal value is difficult to give. In evaluating long-term outcome, the most ideal HQ ratio of an injured knee seems to be the HQ ratio of the opposite, healthy extremity.     

Effects of underwater treadmill walking training on the peak torque of the knee in hemiplegic patients

[Purpose] This study investigated the effects of underwater treadmill walking training on the peak torque of the knee in hemiplegic patients. [Subjects and Methods] Thirty-two subjects, who were randomly allocated to an experimental group (n=16) and a control group (n=16), performed underwater treadmill walking training and overground treadmill walking training, respectively, for 30 minutes/session, 3 sessions/week, for 6 weeks. An isokinetic dynamometer was used to assess the peak torque. [Results] The subjects in the experimental group showed an increase in the peak knee extension torque compared to the control group. [Conclusion] The results suggested that underwater treadmill walking training has a greater effect on peak knee extension torque at velocities of 60°/sec and 120°/sec than overground treadmill walking training.Key words: Knee joint, Stroke, Underwater treadmill     

Differences in elbow flexion torque measured concentrically, eccentrically, and isometrically

The purposes of this study were to describe torque-velocity relationships during concentric, eccentric, and isometric testing of elbow flexor muscles and to determine test-retest reliability of a specific isokinetic testing protocol. Thirty healthy women were tested using an isokinetic dynamometer at velocities of 0 degrees, 30 degrees, 120 degrees, and 210 degrees/sec. Reliability was assessed in 20 of the subjects by retesting concentric and eccentric torques at 30 degrees and 120 degrees/sec after a 30-minute rest interval. The highest torque from three maximal efforts was considered to be peak torque. Mean eccentric peak torque was greater than either isometric or concentric peak torque; as isokinetic test velocity increased, the differences between concentric and eccentric torques became larger. Intraclass correlation coefficients ranged from .72 to .83, indicating lack of consistency between test and retest torques. Consecutive concentric-eccentric testing and lack of mechanical stabilization might have contributed to test-retest variability and to the relatively small differences between concentric and eccentric torques. Continued study of reliability of isokinetic testing protocols and further investigation of concentric-eccentric torque-velocity relationships are advocated.     

The reproducibility of multi-joint isokinetic and isometric assessments in a healthy and patient population

DESIGN: Test re-test reliability design. OBJECTIVE: To determine a reproducible protocol for lower limb simultaneous multi-joint assessments on a healthy group of subjects and a patient group with patellofemoral pain syndrome. BACKGROUND: Although single joint assessment with isokinetic dynamometers has been utilised for many years in knee rehabilitation, simultaneous multi-joint assessment has not attracted comparable attention. METHODS: Twenty healthy volunteers mean age 30.6 years and 16 patients with patellofemoral pain syndrome mean age 29.6 years performed isometric maximum voluntary contractions and concentric isokinetic contractions of the lower limb. Data were collected on three separate days for resultant extension/flexion peak torque, average power and total work which were analysed using intraclass correlation coefficients with a 95% level of confidence. RESULTS: In healthy subjects, intraclass correlation coefficients estimates were > or =0.75 for isokinetic peak torque and >0.83 for average power and total work. The intraclass correlation coefficients estimate for isometric peak torque extension was 0.82. In the patient group, intraclass correlation coefficients estimates were >0.82 for isokinetic peak torque and > or =0.75 for average power and total work. The intraclass correlation coefficients estimate for isometric peak torque extension was 0.89. Discarding the first session's data for both groups improved the intraclass correlation coefficients estimates for virtually all assessments. CONCLUSIONS: This study has demonstrated high reproducibility of lower limb multi-joint testing for peak torque, average power, and total work on healthy subjects and then has employed the protocol to demonstrate similarly high reliability on a patient group. It has also highlighted the need for a practice session before the data can be said to be reliable. RELEVANCE: Reliability studies often use healthy subject groups, which although useful, have limited relevance to patient populations. This study has not only gained comprehensive reproducibility data on multi-joint assessment in healthy subjects, it has also shown that multi-joint testing can be used safely and reliably in patients with patellofemoral pain syndrome. Clinicians may now be able to measure objectively lower limb function in this patient group both pre and post treatment.     

Electromyographic activity of the quadriceps components during the final degrees of knee extension

An imbalance in the recruitment patterns of the quadriceps muscle has been implicated in patellofemoral knee pain; however ambiguity remains in the normal recruitment patterns of this muscle. We investigated the activity of the quadriceps muscle during the final degrees of knee extension, specifically in the medial and lateral components. Sixteen healthy subjects (age; 22.5 (± 3.4) years, body mass; 67.5 (± 12.1) kg and height; 173.9 (± 10.4) cm) participated.Torque and electromyographic (EMG) activity of the quadriceps muscle were measured during isokinetic and isometric knee extensions. Torque and EMG activity reduced in all component muscles during the final degrees of isokinetic extension, but this did not occur during isometric contractions at similar angles. Normalised activity of rectus femoris (RF) was greater than that of vastus lateralis (VL) and vastus medialis obliquus (VMO) during the final degrees of isokinetic knee extension at 30°/sec; there were no differences between any component muscles at the higher velocities. VMO:VL and vastus medialis longus (VML):VL ratios were unchanged during knee extensions, except that VML:VL ratio increased significantly during the final degrees of extension at 30°/sec. Future work should compare these results with people with anterior knee pain, and explore this further during activities of daily living.     

Comparison of the long-term effectiveness of progressive neuromuscular facilitation and continuous passive motion therapies after total knee arthroplasty

[Purpose] The aim of this longitudinal study was to examine the long term functional effectiveness of proprioceptive neuromuscular facilitation (PNF) after total knee arthroplasty. [Subjects and Methods] We included 30 patients and they were randomly assigned to two groups. In addition to the standard rehabilitation program the PNF group received proprioceptive neuromuscular facilitation therapy and the CPM group received continuous passive motion therapy. The outcome measures included range of motion using a goniometer, pain scores using a numeric pain rating scale, days to reach functional benchmarks, the Beck depression scale and isokinetic torque and isometric strength measurements. [Results] There were no significant differences between the two groups in terms of baseline demographic data, clinical findings and length of stay. Days to reach range of motion benchmarks were similar in the two groups. Pain at the 8th week was slightly higher in the PNF group. With the exception of walking with a walker, days to reach functional benchmarks were statistically significantly fewer in patients of the PNF group despite similar isokinetic measurements. Administration of PNF resulted in earlier functional gains in patients after total knee arthroplasty. These functional accomplishments were more pronounced in the PNF group despite it having isokinetic torque measurements similar to those of the CPM group. [Conclusion] PNF techniques can positively affect functional outcomes over the long term.Key words: Functional gains, Proprioceptive neuromuscular facilitation, Total knee arthroplasty     

Knee flexor and extensor strength ratios with deficiency of the lateral collateral ligament

This investigation studied the peak torque and total work hamstring/quadriceps (HQ) ratios of 24 lateral collateral ligament (LCL) insufficient knees, and clarified the possible associations between different HQ ratios and the long-term outcomes of patients. Peak torque values were recorded at low (60 degrees/sec) and high (180 degrees/sec) speed of isokinetic movement, and the maximal isometric extension and flexion outputs were measured at the knee angle of 60 degrees from straight. Three standardized knee scoring scales were used to determine the subjective, functional, clinical, and radiologic outcomes of these LCL insufficient knees. In every test a great interpersonal variation of the HQ ratios was noticed, even in the healthy knees (range 24% to 154%). On the injured side the HQ ratios were in every test higher than on the healthy side, because of the weaker quadriceps muscle of the injured leg. In most cases, followup scores did not differ significantly between the groups with low (less than 50%), optimal (50% to 80%), or high (greater than 80%) HQ ratios of the LCL insufficient knees. However, in every test the scores were significantly (p less than 0.005 to 0.0001) better in the patients who had the HQ ratio of the injured knee near the uninjured side (less than 15%) compared with those with a clear difference (greater than 15%). These findings suggest that the HQ ratio is a very individual parameter, and therefore any general recommendation about the optimal value is very difficult to give. With regard to long-term outcome, the most ideal HQ ratio of an LCL insufficient knee seems to be the HQ ratio of the opposite, healthy extremity.     

Nature, reliability, and predictive value of muscle performance measures in patients with hemiparesis following stroke.

The purposes of this investigation were to examine among a sample of hemiparetic stroke patients the nature and reliability of selected muscle performance measures and the correlation between the measures and gait speed. Fourteen subjects who met specific entry criteria participated. The Lido Active Rehabilitation System was used to obtain bilaterally all muscle performance measures of knee extension (velocity, isometric torque-peak and time specific, and time to peak torque and 90% peak torque). Gait speed was measured under both "comfortable" and "maximum safe" conditions. In addition to lower torques, the subjects demonstrated slower knee extension speeds and longer times to peak torque and 90% peak torque on the paretic than on the nonparetic side. High intrasession reliabilities were demonstrated for all muscle performance measures except the torque at 0.1 sec on the nonparetic side and the time to peak torque and 90% peak torque measures. Significant correlations were demonstrated between both gait speeds and paretic knee extension torque (except at 0.1 sec), nonparetic knee extension torque at 0.1 sec and 0.2 sec, and time to nonparetic peak torque. Muscle performance measures other than peak torque appeared to offer little advantage (alone) over paretic peak torque for predicting gait speed. Over 74% of the variance in gait speed, however, could be predicted by the peak isometric peak torque of the paretic side and the time to peak torque on the nonparetic side, together. Thus, there may be benefits to testing the muscle performance of both lower extremities when examining patients with stroke.     

Determining the number of repetitions to establish isokinetic knee evaluation protocols specific to angular velocities of 60°/second and 180°/second

IntroductionThis study aims to develop a standard number of repetition at angular velocities of 60°/sec and 180°/sec and define the difference of number of repetitions between genders.MethodOne hundred ninety-six athletes (judo, volleyball, Greco-Roman wrestling, runners, and gymnastics) were involved. Concentric-concentric isokinetic muscle strength of the knee flexor-extensor muscles of the athletes were performed with an ISOMED 2000 isokinetic dynamometer. The evaluation test protocol consisted of 10 repetition of knee flexion-extension at 60°/sec and 30 repetitions at 180°/sec.ResultsAthletes performed with maximal knee flexion strength at their second and third trial at 60°/sec and third-forth trial at 180°/sec. It was found that 2 repetitions and 2–3 repetitions were needed for knee extension peak torque at 60°/sec and 180°/sec respectively. The difference between the genders was significant at 60°/sec for knee flexion and extension on the dominant side; at 180°/sec for knee extension on the dominant and non-dominant side. It was determined that 3 repetitions for 60°/sec, 4 repetitions for 180°/sec were enough to determine peak torque values.DiscussionOptimal number of repetitions is crucial so that athletes could have the opportunity to reach maximal strength without unnecessary workload or waste of time.ConclusionsProtocols involving 3 repetitions for 60°/sec, 4 repetitions for 180°/sec were enough to determine peak torque values. Gender of athletes should be considered when establishing isokinetic knee evaluation protocols.     

Reliability of knee extension and flexion measurements using the Con-Trex isokinetic dynamometer

The aim of this study was to evaluate the reliability of isokinetic and isometric assessments of the knee extensor and the flexor muscle function using the Con-Trex isokinetic dynamometer. Thirty healthy subjects (15 males, 15 females) were tested and retested 7 days later for maximal strength (isokinetic peak torque, work, power and angle of peak torque as well as isometric maximal voluntary contraction torque and rate of torque development) and fatigue (per cent loss and linear slope of torque and work across a series of 20 contractions). For both the knee extensor and the flexor muscle groups, all strength data - except angle of peak torque - demonstrated moderate-to-high reliability, with intraclass correlation coefficients (ICC) higher than 0.86. The highest reliability was observed for concentric peak torque of the knee extensor muscles (ICC = 0.99). Test-retest reliability of fatigue variables was moderate for the knee extensor (ICC range 0.84-0.89) and insufficient-to-moderate for the knee flexor muscles (ICC range 0.78-0.81). The more reliable index of muscle fatigue was the linear slope of the decline in work output. These findings establish the reliability of isokinetic and isometric measurements using the Con-Trex machine.     

Continuous versus separate isokinetic test protocol: the effect of estradiol on the reproducibility of concentric and eccentric isokinetic measurements in knee muscles.

OBJECTIVE: To investigate the effects of estradiol on the reliability of concentric and eccentric isokinetic measurements of knee muscles and to compare the reproducibility of measurements in a continuous test protocol and a separate test protocol. DESIGN: Repeated measurements. SETTING: A university exercise physiology laboratory. PARTICIPANTS: Twenty healthy sedentary women volunteers, aged 19 to 37 years, who had regular menstrual cycles (ranging from 27 to 35 days). Subjects were randomly divided into two groups: continuous test group (n = 10) and separate test group (n = 10) and tested at the menstrual phase (days 1 to 3) and preovulatory phase (days 12 to 14) in both legs. METHODS: Continuous reciprocal flexion-extension contractions were used in the continuous test group, and separated flexion and extension contractions were used in the separate test group. Four different test protocols were designed to determine the effects of test mode and number of contractions on the isokinetic measurements: Group A, 4 reciprocal flexion-extension repetitions at each angular velocity of 60 degrees/sec and 180 degrees/sec in one leg in the continuous test group; Group B, 4 and 20 reciprocal flexion-extension repetitions at 60 degrees/sec and 180 degrees/sec, respectively, in the contralateral leg in the same group; Group C, 4 repetitions in extensors and flexors at each angular velocity of 60 degrees/sec and 180 degrees/sec with a 5-minute rest between the two muscle groups in one leg in the separate test group; and Group D, 4 repetitions at 60 degrees/sec and 20 repetitions at 180 degrees/sec for extensors and flexors with a 5-minute rest between the two muscle groups in the contralateral leg in the same group. Blood samples were analyzed for sex hormones, creatine kinase, and lactate dehydrogenase before the tests at the menstrual phase and the preovulatory phase. In addition subjective assessment of muscle soreness was made at each blood sampling. RESULTS: Concentric and eccentric peak torque, average power, total work, and endurance ratio at both angular velocities were not significantly different in the two phases of the cycle by paired observation t test for each of the four groups. Except for concentric and eccentric endurance ratios of quadriceps and hamstrings, and concentric peak torque and average power of hamstrings at 180 degrees/sec in Group D, intraclass correlation coefficients of tested variables showed correlations that were moderate to excellent (p < .05) between two phases. In addition, there were no significant correlations between estradiol and the tested variables. Resting serum creatine kinase and lactate dehydrogenase activities and the score of muscle soreness were at the baseline and not significantly different prior to the tests performed at preovulatory and menstrual phases. CONCLUSIONS: The results suggest that: (1) reproducibility of isokinetic tests during the menstrual cycle is not influenced by sex hormone fluctuations, particularly estradiol; (2) when compared with the separate test protocol used in this study, the continuous test protocol is more appropriate to measure peak torque, average power, total work, and endurance ratio for both muscle groups of the knee even if the number of contractions is changed. However, these conclusions are specific to sedentary individuals; to make more valid conclusions, further studies with different subject groups are needed.     

Reliability of knee extensor and flexor torques during continuous concentric-eccentric cycles

Peak and average torques of the knee extensors and flexors were determined on three occasions within ten days. On each occasion, 20 healthy women and 15 healthy men performed three continuous concentric-eccentric cycles with no pause between muscle actions or between cycles at 45 degrees and 90 degrees/sec angular velocities. Peak and average torques did not vary significantly or systematically over the three test occasions. Intraclass correlation coefficients (ICCs), based on one occasion, ranged from 0.79 to 0.91 for peak torques and from 0.75 to 0.88 for average torques. At 45 degrees/sec angular velocity, the ICCs for peak torque tended to be greater than those for average torque, whereas at 90 degrees/sec angular velocity the ICCs were similar whether calculated using peak or average torque. The ICCs during knee extension were greater than those during knee flexion. Eccentric muscle actions produced significantly higher torques than did concentric actions (p less than 0.01). A continuous concentric-eccentric cycle protocol which emphasizes teaching the subject to perform the test maneuvers and using at least three submaximal practice contractions and one maximal practice contraction can produce reliable isokinetic torques.     

Electrically elicited fatigue test of the quadriceps femoris muscle. Description and reliability

The purposes of this study were to develop an electrically elicited fatigue test (EEFT) that uses electrically elicited isometric muscle contractions and to examine the reliability of this test on a group of healthy individuals. Fifteen subjects were tested on two occasions, one week apart. The subjects were seated and the left leg secured to an isokinetic dynamometer with the knee positioned at 45 degrees of flexion. Maximum voluntary isometric contraction (MVIC) of the quadriceps femoris muscle was obtained and resultant knee extension torque was recorded. The quadriceps femoris muscle then was stimulated 50 times at the current level that elicited a knee extension torque level equal to 60% of that obtained during the MVIC. Percentages of decline in torque were calculated. Test-retest reliability indexes were calculated for the means of contractions 21 to 25 (r = .82, ICC = .83) and for contractions 46 to 50 (r = .92, ICC = .82). The EEFT was found to be reliable and may provide a clinically applicable means of measuring peripheral muscle fatigue.     

Knee extension torque during repeated knee extension-flexion reversals and separated knee extension-flexion dyads

I measured the knee extension torque, produced by eight hemiparetic patients during repeated knee extension-flexion reversals and during separated knee extension-flexion dyads, to determine the effect of "reversal of antagonists" on knee extension torque. The hemiparesis in these eight patients was secondary to intracranial lesions. I tested their involved lower extremity on an isokinetic dynamometer at 60 degrees/sec. Using a sequential medical-trials design, I found knee extension torque to be significantly greater during repeated knee extension-flexion reversals than during separated knee extension-flexion dyads (p less than .05). I, therefore, concluded that reversal of antagonists may facilitate knee extension torque production in the type of patients tested, under the specific conditions of their testing.