Isokinetics and Exercise Science - Volume 5, issue 1
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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: The primary purpose of this study was to provide descriptive data on elite junior tennis players regarding isokinetically measured quadricep and hamstring strength. Eighty-seven (62 male and 25 female) elite junior tennis players underwent bilateral isokinetic knee extension/flexion testing on a Cybex 300 series dynamometer system. Speeds of 180 and 300 degrees per second were used for males, and 300 degrees per second was used for females. The parameters of peak torque (PT) and single repetition work (SRW) were analyzed. Results showed no significant difference between extremities for either quadricep or hamstring strength for males or females at any testing…speed for either (PT) or (SRW). This finding of bilateral symmetry is in contrast to upper extremity isokinetic strength data showing significant unilateral dominance in tennis players from this population. Data from this study are presented in the relative form and are important for interpretation of isokinetic lower extremity strength tests from athletes in this population. Based on the results of this study, it appears that symmetrical lower extremity strength can be expected in the quadricep and hamstring musculature of elite junior tennis players.
Abstract: Various devices and test protocols have been used during isokinetic assessment of human muscle performance. The purpose of this investigation was to examine the effects of continuous and interrupted test protocols and test device on concentric quadriceps peak torque (PT) production. PT was measured via two commonly employed isokinetic test devices (Cybex II and Kin-Com) and test protocols (interrupted (I) and continuous (C)). Thirty-one male subjects (× age 23.0 ± 2.07 years, × wt 78.2 ± 12.2 kg, × ht 177.8 ± 6.45 cm) were tested at 1.08 rad/s (600/second), 48 h apart on each device in random order. Because…the devices correct for gravity differently, gravity correction was eliminated from all test conditions. Preload and damp were applied in order to replicate clinical protocols as closely as possible. Intraclass correlation coefficients (2,3) (and standard errors of measurement) were 0.88(7.52 N·m) (I) and 0.91 (7.04 N·m) (C) for the Kin-Com, and 0.98 (3.30 N·m) (I) and 0.92 (8.42 N·m) (C) for the Cybex. A 2 × 2 within subjects ANOVA demonstrated significant differences between Cybex (damped) and Kin-Com (preload) PT measures (P ≤ 0.05). An interaction for device × protocol demonstrated greater peak torque values for the I protocol (Kin-Com: 199.1 ± 44.9 N·m, Cybex: 181.7 ± 35.0 N·m) than for the C protocol (Kin-Com: 182.2 ± 35.5 N·m, Cybex: 183.3 ± 33.9 N·m) (P < 0.05) for the Kin-Com although the Cybex values were the same. Although both the interrupted and continuous protocols demonstrate high reliability, the interrupted protocol results in higher quadriceps PT values for the Kin-Com. We conclude that selection of test protocol influences assessment of quadriceps PT when using the Kin-Com isokinetic dynamometer.
Abstract: The purpose of the investigation was to compare contraction periods on two test conditions to assess isometric muscular strength in elementary school girls. Test conditions included a 2-s make and 5-s make test with the order of the tests counterbalanced. Twenty-five girls aged 9–11 were assessed with a hand held dynamometer on two separate occasions 5–7 days apart. Muscle groups were tested alternating body sides and upper and lower muscle groups including hip flexion, knee extension, elbow flexion and shoulder abduction. Based on the data analysis, it was concluded that either contraction period with the make-test procedure was sufficient to…assess isometric muscular strength in elementary school girls.
Abstract: Knee flexion and sagittal tibial translation were measured during stair ascent and descent as well as during maximal isokinetic concentric muscle work with an electrogoniometer chain in ten volunteers without previous knee injury. The tests were repeated 16 times for each knee on different occasions by two examiners. The standard deviation for repeated measurements was ± 1.3 mm and the 95% confidence interval for the difference between repeated measurements was ± 0.9 mm. The test-retest correlations were above 0.80 for the whole group of subjects. There were no significant differences between the right and left knee, different sessions or examiners.…There was a wide range in the amount of translation between different individuals from 2.7 to 10.2 mm. The translations during stair walking were 30–50% smaller than during isokinetic muscle work and the coefficient of variation was therefore higher. There was no difference in translations between stair ascent and stair descent but the amount of translation was larger for cycles ending with both feet carrying body weight than for single support cycles. It is suggested that higher contact forces in the knee diminishes the amount of sagittal translation. This finding indicates that closed kinetic chain exercises may be preferable to minimize translatory forces in the rehabilitation after reconstruction of the cruciate ligaments.
Abstract: The aim of this work was to evaluate the short-term reeducative efficacy by an isokinetic flexion-extension test of the knee in male patients affected by neurological problems/diseases because of vascular infarct. Fifty males, average age 52.5 years, all affected by left normotonic hemiparesis, have been studied by a computerized isokinetic flexion-extension test of the knee at 60 degrees/s and endurance at 180 degrees/s (1-min duration). They were all examined before and after the standardized rehabilitative treatment of 4 years. Each test was performed first on the healthy side and then on the paretic side; the control group was composed of…20 healthy people of the same age. The parameters examined in the test at 60 degrees/s were the following: time to reach peak torque; time to reach isokinesis; time of extensor/flexor transition and vice versa (reciprocal innervation). The parameters evaluated in the endurance test were: peak torque; total work performed and the number of repetitions required to cause a 20, 30 and 50% decrease in the total work slope, the gradient of the fitted line. The results show that, after treatment, muscle strength of the paretic side increased significantly, but it approximates half of the healthy limb values; the difficulties, while of alternate (reciprocal) recruitment in the hemiplegic patient, still remain. In the endurance test the healthy side has functional values between the normal values and those of the pathological side.
Keywords: Isokinetic, Hemiparesis, Computerized evaluation, Training
Abstract: Although investigations have been performed establishing the reliability of portable instruments designed to measure upper extremity strength, little research exists concerning the reliability of portable back and lower extremity isometric dynamometers. Therefore, the purpose of this study was to establish the intrarater reliability of one commercially available isometric dynamometer: the TEC isometric back, leg, and chest dynamometer. Subjects consisted of 27 volunteers (14 males and 13 females), with a mean age of 26.3 ± 4.5 years, who reported no back or lower extremity pathologies. Back and leg strength were measured standing in three positions: (1) knees extended, hips flexed, maintaining…lumbar lordosis; (2) knees extended, hips flexed, spine flexed; (3) knees flexed, hips flexed, maintaining lumbar lordosis. The testing occurred on two occasions, separated by 1 week. Data analysis using intraclass correlations indicated reliability coefficients for all positions were over 0.97. These results indicate excellent intrarater reliability in each of the three testing positions using the TEC isometric back, leg, and chest dynamometer to evaluate healthy individuals.
Abstract: The purposes of this study were to compare isokinetic dynamometer (IKD) and hand-held dynamometer (HHD) based protocols for determining isometric shoulder rotation strength and to quantify the variation that could be expected when interchanging scores. Shoulder external rotation (ER) and internal rotation (IR) torques (Nm) of 20 healthy males and 20 healthy females (mean age 58 ± 9 years) were determined with the subject seated and the glenohumeral joint positioned in the scapular plane, on two separate occasions. RCs were excellent for IKD and HHD protocols, and for parallel reliability between the protocols (Res > 0.86). No significant differences were…observed between test occasions or protocols (P > 0.05). Protocol difference scores (IKD – HHD score) demonstrated good reliability on one occasion (Res > 0.62) and excellent reliability over two occasions (Res > 0.75). No significant differences were observed between protocol difference scores on the two test occasions, or when averaged over occasions (P > 0.05). When interchanging scores, IR torques determined using the IKD and the HHD protocols tended to be similar (0.0 ± 3.2 Nm), whereas during ER, torques determined using the HHD protocol tended to be about 0.8 ± 2.0 Nm higher than those determined using the IKD protocol. Although scores determined using IKD and HHD test protocols were not characterized by precise interchangeability, the range of scores describing interchangeability was relatively small.
Abstract: This article presents a normative database for the Cybex TEF and TORSO spinal isokinetic dynamometers and examines the various applications of the information to the clinical setting. Peak torque percent body weight (PT%BW) data were collected from 27176 normal subjects (13 497 females, 13 679 males; age range 10–79 years) in five occupational categories (industrial, professional, service, student and retired) at the concentric isokinetic speeds of 30, 60, 90, 120 and 1500/s on both the TEF (flexion/ extension) and TORSO (left/right rotation) systems. Statistical analysis (ANOV A) revealed significant differences between test devices, genders, test motions, and subject age by…decade. However, differences did not exist between test speeds or left and right rotation results. Additional findings were that PT%BW output occurred in a hierarchy (extension > flexion > rotation); males produced higher PT%BW levels than females, although performance ratios for each muscle group were very similar; and PT%BW output decreases at a similar rate between muscle groups for both genders across the 10–19 through 70–79 age decades. The results imply that testing at multiple speeds is not necessary on the TEF and TORSO systems; PT&BW data for the spine may be taken from a comfortable single speed within the 30–150 °/s isokinetic velocity spectrum.