bluuebunny/crossref_metadata_2025 huggingface dataset:
Endurance Tests During Isokinetic Contraction: Reliability of Functional Parameters
Authors: Felicetti Guido , Zelaschi Franco , Di Patrizi Stefano
Published: October 2018

This article illustrates a new computerized analysis of endurance during prolonged isokinetic flexor–extensor contraction of the knee and studies its reproducibility. Thirty men 20–30 years of age with no knee pathologies were studied. Each subject performed an endurance test three times, each test separated by 3 days. The evaluation consisted of a cycle of 1 minute of concentric knee flexion–extension actions at an angular velocity of 180 deg/sec. Appropriate computer software was used to process the following parameters: total work and number of repetitions necessary to obtain a 20–30–50% decrement from baseline work, baseline torque, and number and duration of cycles necessary to obtain a 20–30–50% decrement of the peak torque compared with baseline values. The parameters obtained were statistically evaluated. The results showed that there was no difference between left and right sides, and the parameters with the best reproducibility were total work, baseline torque, and the 20–30–50% decrement of work compared with base values.
Effects of External Compression on Isokinetic Muscular Endurance of the Quadriceps and Hamstring Muscle Groups
Authors: Joyce Christopher J. , Bernier Julie N. , Perrin David H.
Published: October 2018

The purpose of this study was to determine whether external compression would cause a decrease in the isokinetic muscular endurance of the quadriceps and hamstring muscle groups. Subjects were tested on the Cybex II dynamometer (Cybex, Ronkonkoma, NY) under two conditions: with external compression applied to the thigh and without external compression applied to the thigh. External compression was applied with a lower extremity blood pressure cuff inflated to a predetermined clinically standardized pressure. The subjects performed an isokinetic endurance test consisting of 30 maximal repetitions at 180 deg/sec under both conditions. A paired t test showed no statistical differences (p > 0.05) between the mean total work, work over the first five repetitions, and work over the last five repetitions between the two conditions for the quadriceps and the hamstring muscle groups. Results indicated that external compression applied to the thigh at 30 mm Hg caused no significant decrease in the isokinetic muscular endurance of the quadriceps or hamstrings. Further research is indicated to determine whether external compression could influence other aspects of muscular performance.
Reliability and Limb Symmetry for Five Unilateral Functional Tests of the Lower Extremities
Authors: Bandy William D. , Rusche Kenneth R. , Tekulve Francis Y.
Published: October 2018

Although gaining popularity in sports physical therapy, few data exist as to the reliability of functional tests for the lower extremity; neither has “normal” right-left symmetry been established. Therefore, the threefold purpose of this study was to (1) describe five common and relatively simple functional tests, (2) investigate the reliability of these tests, and (3) determine the differences in the ability of the right and left limb to perform these functional tests. Testing of these five functional tests was performed three times across a 3-week period using standardized procedures for four different samples, with each sample performing a different functional test. Eighteen volunteers completed the one-legged horizontal hop test, 16 subjects participated in the one-legged vertical hop, and 18 subjects completed the timed one-legged hop test. One sample of 22 subjects participated in both the one-legged triple-hop test and the one-legged cross-over hop test. Results indicated right-left differences of all five functional tests to be less than 1% and reliability correlation coefficients ranged from 0.85 to 0.94. Given the reliability coefficients obtained and the absence of clinically important right-left differences, the data collected from this study suggest that functional tests have the potential to be a valuable adjunct in the assessment of the athlete after injury.
Isokinetics and Muscle Strength Ratios of the Ankle Invertors/Evertors: A Pilot Study
Authors: Hartsell H. D.
Published: October 2018

The purposes of the study were to (1) identify ratios for the evertor and invertor muscles of the ankle and (2) determine whether gender differences existed in ankle strength ratios of healthy, young adults. Twelve females and 13 males consented to be tested bilaterally on a single occasion for ankle inversion and eversion at two velocities (30 and 120 deg/sec) using the Cybex 330 isokinetic dynamometer (Cybex, Ronkonkoma, NY). Two- and three-way analyses of variance and post-hoc Neuman-Keuls tests were used to analyze the data. Results indicated that the invertor muscles were stronger than the evertor muscles at all velocities (26.31% at 30 deg/sec, 29.14% at 120 deg/sec), ankles tested (32.35% for the preferred, 22.23% for the nonpreferred), and genders (26.08% for males, 29.39% for females). With the exception of inversion at the slow velocity for the preferred ankle, there were no differences between the ankles for velocities or movements tested. Similar ratios of eversion/inversion strength were observed for each gender at either velocity. However, ratios differed significantly between the preferred (dominant) and nonpreferred (nondominant) ankles. It was concluded that individual ratios must be used to determine appropriate antagonistic strength ratios for the preferred and nonpreferred ankles (65% and 75%, respectively) and that no differences in gender effect were observed.
Open and closed kinetic chain strength training verse functional exercises to improve performance in patients with ACL reconstructed knees: a prospective study
Authors: Donatelli Robert , Cole Steven P. , Greenfield Bruce , Wooden Michael , Wilkes Joseph S. , Lackey Cassie
Published: October 2018

We evaluated three methods of strengthening the muscles of the lower leg in patients who had surgical reconstruction of the anterior cruciate ligament using an autogenous graft. Thirty-one patients met the study criteria of having a 15% or greater mean torque deficit in a muscle group of the involved leg compared with the same muscle group in the uninvolved leg, when tested on the Musculoskeletal Evaluation Rehabilitation and Conditioning System (MERAC, Universal Corporation, Cedar Rapids, Iowa). Patients were divided into three groups: open-kinetic chain MERAC, closed-kinetic chain Fitnet (Universal Corporation, Cedar Rapids, Iowa) leg press, and functional exercise. Functional testing, open kinetic chain isokinetic testing and closed kinetic chain isokinetic testing were performed on all three groups pre- and post-training. A significant improvement in performance was found for all the groups over time on the MERAC, the Fitnet, and the functional tests. These results indicate that strengthening the muscles of the lower leg and improving function may be less dependent on the type of kinetic chain exercise, than on the muscle groups that are trained. The accommodating preset resistance and no restriction on the speed of movement during the exercise also may playa significant role in the development of strength and function.
Comparisons of sitting, prone and standing tests of knee flexion strength
Authors: Kramer John F. , Walsh Robert , Fowler Peter , Webster-Bogart Susan
Published: October 2018

The purposes of the present study were to compare knee flexion torques determined in three test positions: (1) sitting; (2) prone; and (3) standing. Twenty-one healthy males (mean age 23 ± 2 years) completed tests in all three positions on each of two occasions, using isolated concentric and eccentric muscle actions. All tests were completed at 60° /sec angular velocity, using an. isokinetic dynamometer, with the sitting and prone tests completed using the dynamometer chair/bed. A specially built standing/stabilization frame was constructed to test knee flexion in standing. Averaging scores over two occasions was required to achieve reliability coefficients (ICCs) greater than 0.75 for all tests. Standing tests were characterized by the lowest ICCs and the largest measurement error. Repeated measures analysis of variance (three positions by two muscle actions) indicated that the sitting position produced higher torques than did the prone (P < 0.01) and standing positions (P < 0.01), and the standing position produced higher torques than did the prone position (P < 0.01). All 21 subjects identified the standing position as permitting the fewest accessory movements, and providing the greatest isolation of the knee flexion movement and the hamstring muscles. Standing scores should not be compared with those determined in sitting or prone positions. In situations where the clinician wishes to isolate the knee flexors, the standing position is practical and may be advantageous. Future research needs to determine if reliability for standing tests can be improved and to examine the strength-function relationship for all three positions for testing knee flexion strength.
Angular velocity in eccentric isokinetic dynamometry
Authors: Iossifidou Anna N. , Baltzopoulos Vassilios
Published: October 2018

The purpose of this study was to examine angular velocity fluctuations during isokinetic eccentric movements. The Biodex and KinCom isokinetic dynamometers were used for data recording and analysis. Kinematic analysis was performed to calculate the criterion angular velocity against which the velocity recorded by the dynamometer was tested. The period of constant velocity expressed as a percentage of the whole range of motion ranged between 76.5 and 20.9% for the Biodex and for preset velocities ranging from 30 to 150°/s. The respective values for the KinCom were 66.7–28.1% from 30 to 250°/s. It was also found that the dynamometers' angular velocity measurements are only approximations of the actual angular velocity. In conclusion the results of this study indicate that at high velocities and in cases where the range of motion is limited, the effects of angular velocity to various mechanical parameters such as peak moment, power, work, etc. have to be considered or the measurements have to be limited only to constant velocity periods throughout the range of motion.
Agonist and antagonist moment and EMG-angle relationship during isokinetic eccentric and concentric exercise
Authors: Kellis Eleftherios , Baltzopoulos Vasilios
Published: October 2018

The examination of moment and electromyographic (EMG) activity-angle curves of the agonists and antagonists is important for the determination of the mechanisms responsible for moment production during maximal activation of knee extensors and flexors. The purpose of this study was the examination of agonist and antagonistic activity of knee extensors and flexors at different knee joint angles during isokinetic exercise. Twelve females performed maximum isometric, eccentric and concentric isokinetic efforts of knee extensors and flexors on a Biodex dynamometer. The isokinetic tests were performed at angular velocities of 30, 60, 90, 120 and 150° Is. The EMG activity of vastus lateralis, rectus femoris, vastus medialis and hamstrings was also recorded. The knee extensor and flexor maximal activity was found at angles ranging from 50° to 70° and from 20° to 40°, respectively. The antagonist activity was greater at the initial and final stages of the movement. Three way analysis of variance designs indicated significant differences in the agonist and antagonistic activity of knee extensors and flexors between eccentric and concentric exercise. The results of this study demonstrate that, despite changes in magnitude, the moment-angle and IEMG activity-angle patterns of the agonists were not affected by angular velocity and muscle action conditions. On the contrary, the IEMG activity-angle curves of the antagonists during maximal isokinetic voluntary efforts are affected by angular velocity conditions but were independent of the type of muscle action examined.
Medial-lateral hamstring electromyographic activity during maximum isometric knee flexion at different angles
Authors: Fiebert Ira M. , Pahl Craig H. , Applegate E. Brooks , Spielholz Neil I. , Beernik Karen
Published: October 2018

The purpose of this study was to investigate knee flexion torque and changes in electro myographic (EMG) activity of the medial and lateral hamstrings during isometric knee flexion at different angles. Thirty-four subjects, 17 female and 17 male, between 21 and 33 years of age, with no history of right knee pathology volunteered to participate. Subjects were positioned prone on the Cybex II with their right lower extremity secured in knee flexion. Surface electrodes were placed over the medial and lateral hamstring muscles. Each test session consisted of nine maximal isometric knee flexion contractions. Three contractions, of six seconds each, were recorded at 30, 60, and 90 degrees of knee flexion. Recordings of maximum torque and averaged EMG were made by the Cybex II and the Bioscope, respectively. The results showed statistically significant findings: (1) decreased torque as knee flexion increased (P < 0.0005); (2) men demonstrated greater torque than women (P < 0.05); and (3) EMG activity for both the medial and lateral hamstrings decreased as knee flexion increased with differences between 90 and 30° , and 90 and 60° (P < 0.05). We concluded that the decrease in torque output with increased knee flexion is consistent with present knowledge. The coordinated pattern of declining EMG activity with increased knee flexion for both the medial and lateral hamstring muscles requires further investigation.
The accuracy of velocity measures obtained on the KinCom 500H isokinetic dynamometer
Authors: Dillon Randy W. , Tis Laurie L. , Johnson Benjamin F. , Higbie Elizabeth J.
Published: October 2018

The purpose of this study was to determine the validity of the velocity measures of the Kinetic Communicator 500H isokinetic dynamometer(Chattecx Corp., Inc., Hixson, TN) through the use of the Peak 5 motion measurement system (PPTI, Englewood, CO 90112). Ten healthy college-aged females were filmed with a 200 Hz camera performing concentric knee extension and flexion with their right knee at seven pre-set velocities ranging from 60 to 240 deg/s. The video was automatically digitized and analyzed utilizing the Peak 5 motion measurement system and the angular velocity measures were averaged together in 10 degree increments and compared to the averaged measures from the software of the Kin-Com 500H dynamometer. Because of the small variance in Kin-Com data, correlational analyses could not be performed. Paired t-tests revealed significantly different velocity measures at 90 deg/s, 120 deg/s, 150 deg/s, 180 deg/s, and 210 deg/s at certain points in the range of motion. These differences ranged from 2--6 percent. When compared to the Peak 5 system, the Kin-Com appears to provide an accurate assessment of velocity under clinical conditions.
Gender specificity in the correlation of strength and self-perceived level of physical activity across three age groups
Authors: Bellew James W.
Published: October 2018

Objective: To assess gender differences in the correlation between score on a questionnaire of self-perceived level of physical activity and rank on a test age-groups. Design: Sixty subjects in gender-age groups 20-29, 40-49, and 60-69 years of age. Each completed a self-assessment questionnaire of physical activity prior to isokinetic testing of quadriceps strength during concentric and eccentric conditions at 60 and 120 o .s-1. Ordinal rank on both the strength test and questionnaire were compared to determine whether self-assessment of activity correlated with rank on the strength test. Simple and multiple regression procedures were completed correlating gender, questionnaire score, and strength. Results: Gender specific results showed males rated themselves higher on the questionnaire (p = 0.02). Multiple regression revealed that questionnaire score and age were significantly correlated to rank on the strength test (p = 0.02) in males only. Simple regression failed to show significance between strength test rank and questionnaire score for either gender (p = 0.46). Similarly, no significant relationship was found between age and questionnaire score for either gender. Conclusion: Rank within gender-age group on a test of isokinetic strength may be predicted by age and total questionnaire score in male but nog females. Likewise, between gender differences exist as males consistently rate themselves more active than females.
The effect of electrical stimulation combined with dynamic strength training on healthy individuals
Authors: Burkett Lee N. , Phillips Wayne T. , Alvar Brent , Bartelt Lyle , Stone William
Published: October 2018

Since the early 1960's interest has risen for using electrical stimulation (ES) as a supplement to voluntary effort in strength training programs. The purpose of this study was to evaluate the effectiveness of ES combined with simultaneous maximum dynamic contraction. An experimental, randomized control group was used. The independent variables were three methods of training, (a) isotonic weight training, (b) isokinetic resistance, and (c) isokinetic with ES. The dependent variables measured were, (a) peak torque at 36^0 sec, (b) height in the vertical jump, and (c) time in the 50-yard sprint. Results were analyzed using a 3 times 6 split-plot design. No significant differences were found among groups for the design (F_{2,12} = 1.045, P 0.3816). It was concluded that in groups of healthy individuals, ES combined with dynamic contraction in a training program does not develop strength and/or functional capacity more effectively than isokinetic or isotonic contractions without ES.
The effects of concentric isokinetic strength training of the quadriceps femoris on mechanomyography and muscle strength
Authors: Evetovich Tammy K. , Housh Terry J. , Johnson Glen O. , Housh Dona J. , Ebersole Kyle T. , Smith Douglas B.
Published: October 2018

The purpose of the present investigation was to examine the effect of concentric isokinetic leg extension training on peak torque (PT) and mechanomyographic (MMG) responses. Twenty-one males were assigned into a training (TRN, n=12) or control (CTL, n=9) group. The training group performed six sets of ten leg extensions three days per week for twelve weeks at a velocity of 90\dgs. All subjects were tested every four weeks for PT and MMG responses at a velocity of 90 dgs. The two-way mixed factorial ANOVA indicated a significant increase (p < 0.05) in PT over the twelve weeks for the TRN group but no significant change (p>0.05) in PT for the CTL group. For the MMG there was no significant (p>0.05) interaction, therefore, the TRN and CTL groups exhibited the same pattern of responses over the twelve-week training period. The reason for the increase in PT in the absence of a change in MMG may be due to hypertrophy and/or changes in other muscles involved in leg extension.
Predicting depth vertical jumping distance
Authors: Weiss Lawrence W. , Relyea George E. , Ashley Candi D. , Propst Robert C.
Published: October 2018

If independent variables collectively account for each person's ability to vertically jump, then appropriate manipulations of any or all of these factors would be expected to improve jumping performance.Furthermore, if training may elicit the desired manipulations, then the identification of specific weaknesses would enable clinicians and scientists to individualize interventions so as to maximize the effects. In the present exploratory investigation, equations were developed predicting depth vertical jumping (DVJ) distance, a technique roughly simulating the myriad of scenarios in which a rapidly decelerated linear movement precedes vertical jumping.To accomplish this, body composition and 32 variables generated during the performance of concentric-only velocity-spectrum squats were obtained using 52 men and 50 women. At each of four different squatting velocities four force and four power variables met conservative reliability standards for selection as potential predictors of jumping performance. Two explanatory regression equations generated via a forward stepwise approach yielded R-values of 0.89 and 0.90 and SEE ranging from 0.059 to 0.060 meters (2.32 to 2.36 inches). Relative peak power (peak-power-to-body-weight ratio) during squatting exercises performed at 1.43 meters.sec-1 as well as at each individual's optimal velocity for power production were significant predictors of DVJ distance.The predicted distance was also significantly attenuated if subjects were female. Based upon the variables assessed in this investigation, it appears that for young adults, the higher the relative peak squatting power at moderately fast velocities the greater the DVJ performance, and being female negatively impacts this type of jumping.
Isokinetic and isometric torque values using a Kin-Com dynamometer in normal subjects aged 20 to 69 years
Authors: Phillips Beverley A. , Lo Sing K. , Mastaglia Frank L.
Published: October 2018

{\it Objective:} To obtain normal torque values for the knee extensors and flexors using a Kin-Com dynamometer in a large group of normal subjects.

{\it Design:} We used a Kin-Com dynamometer to measure the isokinetic torque at 60 and 120 deg/sec and isometric torque of the knee extensors and flexors in a sample of 200 normal subjects aged 20 to 69 years.

{\it Results:} Reliability coefficients for average and isometric torque were >0.82 for both intra- and inter-session reliability. Male subjects exerted a significantly greater isokinetic and isometric torque than female subjects for both muscle groups and age was a significant predictor of torque for all tests. The 5th percentile values, as the lower limit of normal, are reported separately for gender and side of testing for each decade of age, and may be used for comparison to patient data providing that the specified testing protocol and a Kin-Com dynamometer are used.
Ammonia and lactate responses to isokinetic arm and leg exercise
Authors: Micalos P.S. , Marino F.E. , Tarpenning K. , Kay D. , Gard M.
Published: October 2018

The purpose of this study was to examine the concentration of blood ammonia (NH $_3$ ) and lactate (La $^-$ ) responses to separate isokinetic arm exercise (AE) and leg exercise (LE). Eleven healthy non-trained subjects (aged 18--22∼yrs, 5 males, 6 females) completed 50 maximal effort concentric isokinetic contractions at 60°/sec for preferred arm (elbow joint) and leg (knee joint) on two separate occasions. Blood was drawn before exercise (Rest), immediately following exercise (End-Ex) and 10 minutes post-exercise (Post-10) and analysed for NH $_3$ and La $^-$ . The exercise intensity was assessed after exercise by presenting the mean(± SE) torque output as a percentage of the peak torque output following the 50 contractions for both AE and LE. The exercise intensity was 78.3 ± 1.4% AE respectively. The fatigue index is a ratio of beginning torque to end torque within the exercise period, which was 62.7 ± 3.7% 78.5 ± 2.8% statistically analysed by ANOVA with repeated measures. There was an increase in NH $_3$ following AE between Rest and End-Ex from 92.7± 7.6 μmol.l $^{-1}$ to 115.3 ± 11.4 μmol.l $^{-1}$ , p < 0.05. There was an increase in La $^-$ following AE between Rest to End-Ex from 1.6 ± 0.10 mmol.l $^{-1}$ to 2.8 ± 0.24 mmol.l $^{-1}$ , p < 0.05. The La $^-$ increased for LE between End-Ex and Post-10 from 2.4± 0.23 to 3.3±0.41 mmol.l $^{-1}$ , p < 0.05. These data suggest a more severe metabolic stress during fatiguing concentric isokinetic AE compared with LE and are consistent with previous findings.
Influence of short hamstring muscles on gravitational torque of the leg and knee extension and flexion concentric isokinetic torque
Authors: Gajdosik Richard L. , Leslie Chad M. , Thorne-Thomsen Aric A.
Published: October 2018

The purpose of this study was to examine the influence of short hamstring muscles (hamstrings) on gravitational torque of the leg (GT) and on knee extension and knee flexion concentric isokinetic torque. Fifteen non-disabled men (ages: 18 to 37 years) with clinically short hamstrings(passive straight-leg-raising ≤ 65°) were measured for the GT in two positions: 1) seated position that included a passive stretch of the hamstrings, and 2) supine position that did not include a passive stretch of the hamstrings. Subjects performed three trials of maximal concentric knee extension and flexion in the seated position under four randomly ordered conditions(60°·s $^{-1}$ with seated GT, 60°·s $^{-1}$ with supine GT, 180°·s $^{-1}$ with seated GT, and 180°·s $^{-1}$ with supine GT). One-way ANOVA analysis showed that the GT measured while seated(36.00 ± 9.58 Nm) was greater than the GT measured while supine (21.00 ± 3.90 Nm) (P < 0.001). The greater GT while seated was explained by the sum of the passive hamstring torque and the true GT. Knee flexion peak torque, knee flexion average torque, and the hamstring/quadriceps average torque ratios were decreased at 60°·s $^{-1}$ (P ≤ 0.023) using the seated GT compared to using the supine GT. The same torque characteristics did not differ significantly for knee flexion at 180°·s $^{-1}$ , or for knee extension at either isokinetic speed. We concluded that hamstring passive torque contributed to greater GT in the seated position, which caused invalid knee flexion torque measurements when tested at 60°·s $^{-1}$ . This evidence supports weighing the leg supine in order to remove hamstring passive torque and to ensure valid knee concentric isokinetic torque measurements when testing at 60°·s $^{-1}$ .
Effect of transient moment-oscillations on the reliability of isokinetic shoulder elevation in the scapular plane
Authors: Mandalidis D.G. , Donne B. , O'Regan M. , O'Brien M.
Published: October 2018

The reliability of gravity corrected average and peak isokinetic moment of the shoulder elevators in the scapular plane, was assessed in 22 male college students without shoulder or neck pathology. Measurements were performed on two occasions, 7 days apart, by the same examiner. Both dominant and non-dominant sides were examined at 60 and 120°·s $^{-1}$ , using Kin Com II dynamometer. Each volunteer was assessed in the seated position, elevating the shoulder between 30--90° with the elbow in extension and the forearm in pronation. Reliability of both non-free and free of transient moment-oscillations (TMO) peak and average moment data (data selected from the entire range and the range of motion where isokinetic velocity was constant and equal to the pre-selected angular velocity, respectively) was determined using the intraclass correlation coefficient (ICC 3,1). The variability of isokinetic moment data associated with normal fluctuations of strength performance over repeated measurements (inter-session variability) was determined using the standard error of measurement (SEM) and the limits of agreement (LOA). The ICC (3,1) values ranged between 0.86--0.95. Inter-sessions variability of isokinetic moment data calculated using 95% Both SEM and LOA revealed lower variability for average compared to peak moment data, non-free compared to free of TMO average moment and for free compared to non-free of TMO peak moment data. Higher ICC values and lower variability was also obtained for peak moment data at the isokinetic velocity of 60 compared to 120°·s $^{-1}$ and for most of the moment data recorded on the dominant compared to the non-dominant side. The present findings suggest that strength changes observed over repeated isokinetic measurements of the shoulder elevators in the scapular plane, may be better identified under certain conditions but they should only be considered as significant changes if they are lower or greater than inter-session variability of isokinetic moment data.
Isokinetic strength of the elbow flexors with the forearm in supination and in the neutral position
Authors: Mandalidis D.G. , O'Brien M.
Published: October 2018

Peak and average moment of concentric elbow flexion was assessed in 30 males without previous elbow or shoulder injuries. Isokinetic assessment was performed with the forearm in supination and in the neutral position, at isokinetic velocities of 30, 60 and 120°·s $^{-1}$ for both dominant and non-dominant sides. Eight volunteers were examined twice to determine test-retest reliability and estimate the variability of isokinetic moment data associated with normal fluctuations of strength performance over repeated measurements (inter-session variability) using the intraclass correlation coefficient (ICC 3,1) and the 95% (95% 3.3--16.2 Nm, respectively. Our findings revealed higher reliability and lower inter-session variability for average compared to peak moment data, the dominant compared to the non-dominant side and at the angular velocity of 120 compared to 30 or 60°·s $^{-1}$ . Isokinetic moment of elbow flexors was significantly greater with the forearm in supination compared to the neutral position (p < 0.001) regardless of the side or the isokinetic velocity used. Isokinetic strength of elbow flexion was significantly decreased, as the velocity increased p < 0.001). The dominant side was also stronger compared to the non-dominant side(p < 0.05). The results of our study suggest that elbow flexors can be reliably assessed with an isokinetic dynamometer. Consistent positioning of the forearm is necessary when isokinetic elbow flexion is monitored in longitudinal studies. A bilateral difference of less than 5% when the contra-lateral is used for comparison in pre and post-injury or rehabilitation situations.
Reproducibility of concentric and eccentric isokinetic strength of the knee flexors in elite volleyball players
Authors: Dauty Marc , Rochcongar Pierre
Published: October 2018

The aim of this study is to define the test-retest reproducibility for measuring the peak torque of the knee flexors according to the isokinetic concentric and eccentric muscle action. The tests were done in two sessions at a 21 day interval. Ten healthy national-level volleyball players, 24.3 years old ± 3.9 were included. Tests took place after the competition season. Evaluation was carried out with a Cybex 6000 dynamometer and the reliability was calculated according to the intra-class correlation coefficient (ICC∼2.1). The protocol consisted of 5 isokinetic concentric contractions at 180°/s followed by 5 isokinetic eccentric contractions at 30 and 60°/s. Results show an excellent reproducibility for isokinetic concentric peak torque at 180°/s. (ICC: 0.94) and very good reproducibility for isokinetic eccentric peak torque at 30 and 60°/s.(ICC: 0.86; 0.83). These results indicate that knee flexion strength at these velocities may be used to estimate the performance of volleyball players.
Treatment of recurrent tendinitis by isokinetic eccentric exercises
Authors: Croisier Jean-Louis , Forthomme Bénédicte , Foidart-Dessalle Marguerite , Godon Bernard , Crielaard Jean-Michel
Published: October 2018

The purpose of this study was to determine the effectiveness of eccentric training models in treating various types of tendinitis and evaluate protection from re-injury when returning to causal activities. Isokinetic eccentric training was administered to 34 patients with chronic tendinitis (9 Achilles, 10 patellar and 15 epicondyllar) with a long duration of symptoms and failure of conventional treatment. Following training which consisted of 20 to 30 sessions of progressive increase of load and speed parameters, a significant reduction of pain indicated by the visual analog scale (average initial value> 6.5, final score ≤ 2.5). Seventy four percent of the patients were completely relieved or presented marked decrease in symptoms when returning to sport and occupational activities, and only 12% state. At the end of treatment, isokinetic assessment revealed no significant concentric or eccentric peak torque asymmetries between involved and non-involved sides. In comparison with pretreatment ultrasound observations which showed systematic hypoechoic lesions and thickness, 14/34 patients recovered homogeneous tendon structure and normalization of the diameter and 15 presented improvement in echostructure. Our treatment model proposing isokinetic eccentric exercises presents a very satisfactory short-term effect on three different localizations of chronic tendinitis.
Knee performance after anterior cruciate ligament reconstruction
Authors: Andrade M.S. , Cohen M. , Piçarro I.C. , Silva A.C.
Published: October 2018

The aim of this study was to determine differences in isokinetic performance, hop tests, range of motion and thigh circumference between the involved and uninvolved leg in patients after 4, 5, 6 and 8 months after anterior cruciate ligament (ACL) reconstruction and to investigate the possible correlation between the different evaluation methods. Fourteen male subjects submitted to intra-articular reconstruction of the anterior cruciate ligament with patellar tendon graft. All parameters improved from the 4th to the 8th month post-op. The deficits were more pronounced for the quadriceps than for the hamstrings, which regained full function at 5 months. Quadriceps performance and thigh circumference were impaired even after 8 months. According to the Lysholm Score, all subjects scored at least as good function and 54% correlation between quadriceps performance and both single and triple hops (0.51--0.63), whilst for the harmstrings the correlations were weak(0.32--0.44). We conclude that: 1) Individuals with anterior cruciate ligament injury present quadriceps weakness even after 8 months of the reconstructive surgery using patellar tendon graft; 2) when an isokinetic dynamometer is not available, horizontal impulse tests can be used to evaluate quadriceps deficiency; 3) thigh circumference should not be used as a measurement to predict muscle performance; 4) the Lysholm Score is not sensitive to detect limitations in muscle performance.
Lower-limb extension power: How well does it predict short distance speed skating performance?
Authors: Liebermann Dario G. , Maitland Murray E. , Katz Larry
Published: October 2018

{\it Purpose:} This study was aimed to explore the relationship between lower limb extension power measured by isokinetic knee extensions (IK) and vertical jumps performed on a force plate (VJ) and speed skating (SS) sprint power measured by a laser device.

{\it Methods:} Twenty elite short- and long-track speed skaters performed 100 m sprints followed by VJ and IK trials. Power-time curves were calculated off-line. Pearson correlation coefficients were used to determine the degree of association between the variables.

{\it Results:} SS sprint power correlates strongly with VJ power(r=0.870; p<0.001) while IK power showed a weaker but significant correlation to both (r=0.707 and r=0.706, respectively; p<0.01). As expected, SS times at 15 m and 100 m were inversely associated with SS sprint power (r=-0.818 and r=-0.909; p<0.001) and VJ power (r=-0.730 and r=-0.763; p<0.001), and to a lesser degree with IK power (r=-0.602; r=-0.618; p<0.01).

{\it Conclusion:} The analyses differentiate between methods of estimating power in speed skaters, and show a strong relationship between initial SS performance and muscular power. Given that 100 m split times strongly relate to final 500 m results (r=0.972; p<0.001, N=332), it is reasonable to believe that an initial power and a stable peak speed before the first curve may lead to achieving the winning edge in short SS events. A finding of particular interest is that isokinetic power results are correlated significantly with the practical outcomes of the performance in spite of the high specificity of the isokinetic testing method.
Effect of movement velocity and movement pattern on the root mean square and the median frequency of the electromyographic activity of the quadriceps during isokinetic testing
Authors: Miller John P. , Croce Ronald V.
Published: October 2018

The purpose of this study was twofold: 1) compare the effect of movement velocity and movement pattern on the electromyographic activity (EMG) of the quadriceps as measured by the Root Mean Square of the electromyogram(rmsEMG) and the Median Frequency of the electromyogram (mfEMG) during isokinetic testing and 2) compare the effect of movement pattern on the torque production of the quadriceps during isokinetic testing. Fourteen healthy adult females with no known knee pathologies and familiarity with isokinetic testing performed six continuous isokinetic movements at $100^{0}·s^{-1}$ , $200^{0}·s^{-1}$ , $300^{0}·s^{-1}$ and $400^{0}·s^{-1}$ . Movements were performed in a reciprocal pattern, (maximal knee extension followed by maximal knee flexion), and a non-reciprocal pattern (maximal extension followed by relaxation of the hamstrings). Statistical analyses revealed there was a difference in the rmsEMG for the quadriceps on the effect of velocity (F=3.2, P<0.05) with post hoc analysis revealing significant differences in the rmsEMG between 100 and $300^{0}·s^{-1}$ (F= 5.6, P<0.05), and between 100 and $400^{0}·s^{-1}$ (F = 6.7, P<0.01) with the highest rmsEMG being seen during the slowest velocities. For the mfEMG there were significant differences when comparing the velocity of movement F= 7.8, P<0.001), specifically when comparing the slowest velocity $100^{0}·s^{-1}$ with $200^{0}·s}^{-1}$ (F = 4.9, P<0.05), $300^{0}·s}^{-1}$ (F= 8.8, P<0.005) and $400^{0}·s}^{-1}$ (F = 22.7, P<0.001) with the highest mfEMG observed at the lower velocities. No difference was noted either in EMG or torque between the reciprocal and non-reciprocal movements. The results of this study suggests that during isokinetic testing the EMG activity of the quadriceps is altered as velocity changes with regard to the rmsEMG and mfEMG. Specifically as velocity increases overall muscle activity decreases as measured by the rmsEMG. In addition as velocity increases there is a shifting toward recruitment of slower velocity muscle fibers as measured by the mfEMG. These results also suggest that movement pattern (reciprocal vs. non reciprocal) does not effect the EMG for quadriceps activity during isokinetic knee extension.
How much is necessary to indicate a real improvement in muscle function? A review of modern methods of reproducibility analysis
Authors: Dvir Zeevi
Published: October 2018

Article without abstract.
Isokinetic assessment of shoulders with impingement syndrome following pain inhibition
Authors: Forthomme B. , Croisier J.L. , Huskin J.P. , Crielaard J.M.
Published: October 2018

Article without abstract.
Isokinetic analysis of the volleyball player at the end range of motion
Authors: Dupuis C. , Tourny-Chollet C. , Beuret-Blanquart F.
Published: October 2018

Article without abstract.
Isokinetic-based comparison of hamstrings – quadriceps ratio between soccer players and sedentary subjects
Authors: Tourny-Chollet C. , Leroy D. , Delarue Y. , Beuret-Blanquart F.
Published: October 2018

Article without abstract.
Evaluation of an assisted sprint training period in swimming
Authors: Girold S. , Calmels P. , Maurin D. , Milhau N. , Chatard J.C.
Published: October 2018

Article without abstract.
Evaluation of athletes with longstanding groin pain
Authors: Delahaye H. , Laffargue P. , Voisin P. , Weissland T. , Letombe A. , Dupont L. , Vanvelcenaher J.
Published: October 2018

Article without abstract.
A longitudinal study of isokinetic characteristics of young athletes and prevention of muscular and joint injury: Preliminary results
Authors: Amato M. , Afriat P. , Portero P. , Croisier J.L. , Legros P. , Desnuelle C. , Bernard P.L.
Published: October 2018

Article without abstract.
Isokinetic strength and multiple sclerosis: Correlation between motor impairment and gait speed according to clinical features
Authors: Thoumie P. , Lamotte D. , Mevellec E.
Published: October 2018

Article without abstract.
Delayed onset muscle soreness induced by eccentric isokinetic exercise
Authors: Croisier J.L , Camus G. , Forthomme B. , Maquet D. , Vanderthommen M. , Crielaard J.M.
Published: October 2018

Delayed onset muscle soreness (DOMS) follows unaccustomed muscular exercise, most notably in the eccentric mode. That concept refers to a dull ache combined with tenderness, stiffness and weakness of the previously active muscles. Isokinetic device constitutes a specific model in generating and investigating DOMS. Respective effects of concentric and eccentric actions have been compared, emphasizing on the variability in the response (serum activity of CK for instance). The particular sensitivity of the hamstrings was underlined although causes remained unexplained. Some treatment have been proposed in the management of DOMS. Several studies reported that anti-inflammatory agents fail to alleviate pain and discomfort even if other authors indicated a relative effectiveness. Based on the repeated-bout effect, submaximal eccentric exercise currently represent the most useful preventive strategy.
Relationship between strength of the trunk and flexibility in healthy subjects
Authors: Thevenon A. , Blanchard-Dauphin A.
Published: October 2018

The current study was designed to determine whether alteration of trunk muscles strength caused modification of spinal and lower limb flexibility in healthy subjects. The study was based on the examination of 50 subjects (25 men and 25 women). In women, the extensibility of posterior muscles and ligaments, measured by Schober index or finger to floor distance, was weakly but significantly related to isokinetic strength of flexor muscles of the trunk, and was inversely related to isokinetic strength of the extensor muscle. In men, no such relation was indicated. Consequently, when measuring the concentric strength of the trunk extensors, particularly in women, trunk flexibility is a factor that needs to be taken account of.
Identification of previous hamstring muscle injury by isokinetic concentric and eccentric torque measurement in elite soccer player
Authors: Dauty Marc , Potiron-Josse Michèle , Rochcongar Pierre
Published: October 2018

Twenty-eight elite soccer players (23 years ± 3.3; 74 kg ±7.5; 178 cm ± 6.5) were tested to find out whether isokinetic parameters could identify sportsmen who had previously suffered from hamstring muscle injury.

Eleven players with 15 previous moderate or major hamstring muscle injuries in the preceding 2 years were compared with 17 controls. Strength was measured using a Cybex Norm isokinetic dynamometer on a concentric and eccentric contraction at the angular speed of 60°/s. An ipsilateral concentric Hamstring-to-Quadriceps ratio lower than 0.6 and an eccentric hamstring asymmetry of more than 10% did not enable identification of soccer players with previous hamstring muscle injury. On the other hand, concentric hamstring torque asymmetry of more than 10% identified the uninjured soccer players (probability of 90.1%). A dynamic control ratio(eccentric hamstring-to-concentric quadriceps) lower than 0.6 provided the best predictor of previous hamstring muscle injury (probability of 77.5%). In conclusion, concentric and eccentric isokinetic evaluation of hamstring muscle at the speed of 60°/s renders the search for previous hamstring muscle injury possible by revealing muscle torque asymmetry, which persists despite the resumption of competitive soccer.
Vertical jump and knee extensors isokinetic performance in professional soccer players related to the phase of the training period
Authors: Malliou P. , Ispirlidis I. , Beneka A. , Taxildaris K. , Godolias G.
Published: October 2018

The aim of the present study was to determine the relationship between vertical jump performance and the isokinetic strength of the knee extensors in professional soccer players at the end of the of the competition period, after the detraining period (before the initiation of the preparatory period) and after the completion of the preparatory period. Eighteen professional soccer players participated in the present study. The peak jumping height (of the squat and counter movement jumps on an Ergojump device) was used as indicator of vertical jump performance. The subjects also performed three submaximal and three maximal isokinetic efforts of the knee extensors at angular velocities of 60 and 180°/s. Pearson product moment correlation analyses were conducted to determine the relationship between isokinetic strength and jumping parameters. The significance level was set at p < 0.05. The analysis indicated that jumping height was moderately correlated with the knee torques at the test velocities after the competition and preparatory period.
Functional and isokinetic assessment of hands with early stage of Rheumatoid Arthritis
Authors: Poulis S. , Kretsi Z. , Apostolopoulos L. , Zeeris H. , Vagenas G.
Published: October 2018

The objective of this study was twofold: to explore the effect of RA on hand grip strength at early stage of diagnosed RA and to support the application of isokinetic evaluation in the assessment of RA.

Twenty women, age 48 ± 5 years, participated in this study: 10 with early stage RA and 10 healthy controls. The evaluation tests were included the Health Assessment Questionnaire (HAQ), Moberg pick up test, range of motion (ROM) of the wrist, grip strength, pinch strength, visual analogue pain scale (VAPS) and isokinetic evaluation of concentric and eccentric strength of the wrist flexor and extensor muscles.

The statistical analysis showed no differences in ROM, grip and pinch strength and in the isokinetic evaluation measurements between the two groups. The HAG showed that women with early stage RA have no difficulty in performing daily activities, and there was an increase of completion time due to loss of optical control in the Moberg pick up test in both groups.

In conclusion, women with early stage RA do not present with any significant impairment as indicated by the above-mentioned tests.
Training and testing in open versus closed kinetic chain
Authors: Mayer F. , Schlumberger A. , van Cingel R. , Henrotin Y. , Laube W. , Schmidtbleicher D.
Published: October 2018

Optimization of different forms of training and testing in sports and therapy has traditionally been debated by various groups. Especially, the use of so-called open and closed kinetic chain exercises has frequently been a focal point.

Scientific studies have indicated that no specific form of exercise and/or training has any particular advantage over the other. This applies to both assessment of efficiency, consideration of compression and shear forces, muscular activity and the extent of co-contractions. Unlike the broadly-applied non-specific and uncritical assessment of open and closed kinetic chain exercises, a specific application using the advantages of both procedures must be considered due to clinical, therapeutic and training-physiological aspects. Specificity refers to the training of either an isolated joint-muscle unit(arthron) or a system (group) of joints and muscles.

Considering the original definitions and past misinterpretations, it appears logical to emphasize the role of physiological mechanisms operating in each form of training and testing. Therefore, the use of the term: single-joint(SJ) or multi-joint (MJ) training, is recommended since this would best reflect the area of application, according to a recent consensus expressed by EISCSA.

Consequently, SJ and MJ exercises should be applied both in isolation and in combination as indicated by the principles of specificity. On the other hand, continuous use of the terms open and closed kinetic chain exercises is confusing, erroneous, leads to polarizing discussions and should hence be relegated to the past.