Isokinetics and Exercise Science - Volume 11, issue 3
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Isokinetics and Exercise Science (IES) is an international journal devoted to the study of theoretical and applied aspects of human muscle performance. Since isokinetic dynamometry constitutes the major tool in this area, the journal takes a particular interest in exploring the considerable potential of this technology.
Isokinetics and Exercise Science publishes studies associated with the methodology of muscle performance especially with respect to the issues of reproducibility and validity of testing, description of normal and pathological mechanical parameters which are derivable from muscle testing, applications in basic research topics such as motor learning paradigms and electromyography. The journal also publishes studies on applications in clinical settings and technical aspects of the various measurement systems employed in human muscle performance research.
Isokinetics and Exercise Science welcomes submissions in the form of research papers, reviews, case studies and technical reports from professionals in the fields of sports medicine, orthopaedic and neurological rehabilitation and exercise physiology.
Abstract: 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.
Abstract: Objective: To determine the influence of ageing on lean muscle area and isometric and concentric and eccentric muscle strength in the upper and lower extremity in a cross-sectional study design. Subjects and methods: Lean muscle area and maximal muscle strength (isometric and isokinetic, 60° and 120°/s) of both upper and lower extremity were assessed of 45 men and 56 women (20 to 89 years). Results: One-way variance analysis and regression analyses revealed a parallel…decline with age in both sexes for maximal muscle strength. The decline in maximal muscle strength from age 60 was 34 to 45% in men and 11 to 32% in women in the arms and 40 to 47% in men and 37 to 45% in women in the legs. Isometric, concentric and eccentric contractions showed a similar decline in ageing in both sexes. There was a better maintenance with age of the strength in the arms than in the legs (p < 0.01) and at 120°/s than at 60°/s (p < 0.05). Conclusions: The present findings suggest a parallel decline in lean muscle area and strength and similar losses in isometric, concentric and eccentric strength with increasing age.
Abstract: Manual massage is considered an important part of athletic rehabilitation or preparation for training and competition. Objective: To study the possible effects of manual massage on concentric and eccentric peak torque of knee extensors, when applied during intervals of exercise. Methods: Twelve elite female Tae Kwon Do athletes were tested twice during a week (different extremity each) in continuous concentric/eccentric isokinetic exercise (6 sets of 10 repetitions, with 2 minutes intervals). Manual massage was…applied during breaks to the extremity (massage extremity) while for the other limb (control extremity) the interval was passive. For both groups peak torque was measured 3 minutes after the last set. The same test was performed 3 minutes prior to the first set. The best performance was recorded pre- and post-exercise and the results were compared. Results: For both groups peak torque (concentric and eccentric) was reduced after the exercise protocol. In the massage group the reduction was lower and significantly different for eccentric type of muscle work (p < 0.05). Conclusions: Application of manual massage during isokinetic exercise intervals has an enhancing effect on the peak eccentric torque of the knee extensors.
Abstract: In sprint swimming, thigh muscles strength and body composition may contribute to the development of a good performance in the water. The present study describes the relationship between lean body mass (LBM) and isokinetic peak torque (PT) of knee extensor and flexor muscles in male (n = 31) and female (n = 22) competitive swimmers aged 10 to 12 years. Skinfold thickness measurements for percent body fat and LBM were recorded. Isokinetic testing consisted of concentric…knee extensions and flexions at 60°/s, 120°/s and 180°/s. High correlation coefficients (Pearson's r: 0.765–0.890, p < 0.001) indicated a strong relationship between LBM and knee muscles strength at all angular velocities. Using linear regression analysis, PT could be predicted from the LBM for this particular age and sex groups. However, a simple linear model between LBM and PT could not be constituted as complementary biological parameters, such as flexibility and muscular endurance could also account for the variability.
Keywords: lean body mass, isokinetic, concentric, peak torque, prediction, swimming
Abstract: 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.
Keywords: vertical jump, isokinetic peak torque, knee extensors, soccer players, training period
Abstract: Study design: A correlation study to determine the relationship of the results of linear isokinetic testing and various functional tests. Objectives: To determine the relationship of scores on a linear isokinetic test to scores on a variety of lower extremity functional tests. Background: Both isokinetic testing and functional tests are commonly used during the rehabilitation of individuals with sports and orthopedic injuries. Limited information exists regarding the relationships of scores on a linear…isokinetic test and scores on functional tests. Methods and measures: Twenty-nine healthy subjects performed a velocity spectrum linear isokinetic test consisting of 3 sets in a bilateral reciprocal mode, followed by three sets in a bilateral coupled mode. Testing velocities were 25.4, 50.8 and 76.2 cm per second. Six maximal volitional linear isokinetic repetitions were performed at each testing velocity. Following linear isokinetic testing, subjects performed 5 functional tests: bilateral leg vertical jump, unilateral leg vertical jump, double leg jump for distance, single-leg hop for distance, and single-leg timed 6-meter hop. Functional testing entailed 3 maximal volitional attempts of the 5 procedures for both the dominant and non-dominant lower extremity. The mean of the 3 attempts was used for calculations. Means and standard deviations of the functional test scores and isokinetic test scores were determined using standard statistical procedures. Pearson product moment correlation coefficients were used to determine the relationship between the mean scores on the linear isokinetic test scores and functional tests for both the dominant and non-dominant limbs. Results: Twenty-three out of 36 correlation coefficients were significant at the p < 0.01 level, whi1e 12 out of 36 were significant at the p < 0.05 level. Only 1 out of 36 was non-significant when comparing bilateral reciprocal scores to single-leg functional test scores. The bilateral reciprocal correlation coefficients ranged from -0.36 to 0.65. Six out of 12 bilateral coupled correlation coefficients were significant at p < 0.01, while 3 out of 12 were significant at the p < 0.05 level and only 3 were considered non-significant. The bilateral coupled correlation coefficients ranged from 0.11 to 0.64. Conclusions: Results from this study indicate a significant relationship exists between the results of linear isokinetic testing and various functional tests. Despite the significant relationship, the majority of Pearson Product moment correlation coefficients were in the low to moderate range. Therefore, the use of either a linear isokinetic test or a functional test in isolation to determine strength and performance is strongly discouraged. Linear isokinetic testing should be used for testing lower extremity strength, while functional tests should be used to determine performance levels. The authors recommend utilizing both testing methods since strength does not always correlate strongly with physical performance.