Isokinetics and Exercise Science - Volume 17, issue 3

Authors: Zemach, L. | Almoznino, S. | Barak, Y. | Dvir, Z.

Article Type: Research Article

Abstract: The objective of this study was to find out whether the use of multiple velocity (30, 60, 90 and 120°/s) isokinetic as well as a single angle isometric testing was justified for assessing unilateral muscular weakness. Twenty one unilateral knee patients (16 men, 5 women), mostly with ACL pathology, with a mean post-injury time of 36 ± 33 m, were conveniently sampled. All patients filled in a functional questionnaire which indicated good recovery. The relative weakness …of the involved (I) side was determined using the uninvolved (U) side as reference. Patients were also asked to rank the difficulty in performing the tests. The mean (based on the 4 velocities) eccentric weakness (19.7%) was significantly higher than in both the concentric (14.9%) or the isomteric (13.9%) modes. However within either the concentric or eccentric modes no between-velocity differences were noted. Side dominance had a significant effect on quadriceps weakness in all test modes. In conclusion, and with respect to the specific patient group, the use of one or, at most, two test velocities is sufficient to portray muscular insufficiency. Show more

Keywords: Strength, insufficiency, isokinetic, quadricpes

DOI: 10.3233/IES-2009-0344

Citation: Isokinetics and Exercise Science, vol. 17, no. 3, pp. 129-133, 2009

Authors: Lamotte, M. | Chevalier, A. | Jamon, A. | Brassine, E. | van de Borne, Ph.

Article Type: Research Article

Abstract: Background: Isokinetic evaluation and training are commonly used. Hemodynamic response during this type of exercise is unknown and therefore usually not recommended in some patients (elderly, patients with risk factors or with cardio-vascular disease). The aim of this study was to evaluate the hemodynamic response during a classical testing and training isokinetic session. Method: 20 healthy young male participated to this study. The hemodynamic response wa continuously and non invasively (Task Force Monitor) …measured on a Cybex Norm (knee extension and flexion). The hemodynamic parameters were systolic blood pressure (SBP), heart rate (HR) and cardiac output (Q). Results: A low speed (60°/s) test was more exhausting than one at higher speed (180°/s) which is probably related to its duration. Whereas rest periods seemed sufficient for muscle recovery allowing during training, maintenance of performance over the different sets, changes in hemodynamic parameters (HR, SBP & Q) were observed over successive sets and did not recover totally during rest. Systolic ejection volume did neither change nor contribute to the increase of cardiac output (+ 70 to 84% compared to rest). Values measured during test and training were high but not excessive (HR max=135 ± 20 bpm or 70% of HRmax predicted; SBP max =185 ± 26 mmHg; Q=11.2 ± 2.2 l/min). Conclusions: Values measured during test and training are high but not excessive. Isokinetic training in cardio-vascular risk patients should be composed of shorter set duration and longer rest periods as generally applied, without loosing maximal muscle contraction over the entire rage of motion. Show more

Keywords: Hemodynamics, blood pressure, heart rate, cardiac output, resistive training, strength training, isokinetic

DOI: 10.3233/IES-2009-0345

Citation: Isokinetics and Exercise Science, vol. 17, no. 3, pp. 135-143, 2009

Authors: O'Sullivan, Kieran | Sainsbury, David | O'Connor, Richard

Article Type: Research Article

Abstract: Measurement of muscle size is often used to estimate muscle strength. The validity of these measurements as indicators of muscle strength is unclear however. This study investigated the relationship of two simple measures of muscle size (tape and ultrasound) with the concentric isokinetic quadriceps and hamstrings strength of a group of Irish Gaelic footballers (n=25). Both tape and ultrasound demonstrated moderate to excellent reliability at measuring quadriceps and hamstrings muscle size (ICC's …0.69–0.99). Hamstrings were significantly stronger on the dominant limb at 60°/sec (p=0.046) and 180°/sec (p=0.005), but not at 300°/sec (p=0.092). There was no significant difference in quadriceps strength at any speed (all p> 0.05). Dominant limbs were significantly larger using the tape measure (10 cm level: p=0.005, mid-thigh level: p=0.003). The dominant hamstrings (p< 0.001), but not the dominant quadriceps (p=0.399), were significantly larger on ultrasound. There were statistically significant correlations between muscle strength and muscle size measurements, especially for the tape measurements. However, despite the fact that the dominant limb muscles were both stronger and larger, the strength of these correlations was only weak to moderate (r=0.176–0.586). The results suggest that both tape measurement and ultrasound, while reliable, are of limited use as indicators of thigh muscle strength. Show more

Keywords: Ultrasound, isokinetics, muscle, size, strength, tape measurement

DOI: 10.3233/IES-2009-0346

Citation: Isokinetics and Exercise Science, vol. 17, no. 3, pp. 145-153, 2009

Authors: Hadzic, Vedran | Sattler, Tine | Topole, Eva | Jarnovic, Zoran | Burger, Helena | Dervisevic, Edvin

Article Type: Research Article

Abstract: Injuries in volleyball are sport specific and occur around the net during spiking and blocking. The most common acute injury in volleyball is ankle sprain. There are limited data about the intrinsic risk factors for the ankle sprains in volleyball players. We investigated the influence of muscle strength, postural balance and active range of motion on the ankle sprain occurrence in volleyball players. In 38 professional volleyball players we have tested the strength of plantar and …dorsal flexors using isokinetic dynamometer. Dynamic postural balance was measured using Biodex Balance System and active range of motion was tested by the means of universal goniometry. Following the testing players were prospectively followed up over a season, with injuries and exposure rates registered by the team coaches. Binary logistic regression was used to evaluate the role of individual risk factors. The main findings of our study indicate that higher strength of plantar flexors (odds ratio 1.22, 95% C.I. 1.04–1.43, p< 0.05) and decreasing range of motion in dorsiflexion (odds ratio 0.63, 95% C.I. 0.41–0.97) are significant risk factors for the ankle sprain. The results are suggesting that both risk factors are limiting the ability to land safely from a jump, and that plyometric exercises, proper landing technique and gastrocnemius stretching should be emphasized in the preventive training programs in volleyball players. Show more

Keywords: Volleyball, ankle sprain, risk factors, isokinetics

DOI: 10.3233/IES-2009-0347

Citation: Isokinetics and Exercise Science, vol. 17, no. 3, pp. 155-160, 2009

Authors: Wright, James | Ball, Nick | Wood, Louise

Article Type: Research Article

Abstract: The objective of this study was twofold: first to assess the effect of fatigue on two muscle strength ratios: the conventional ratio – H_{con} /Q_{con} and dynamic control ratio(DCR) – H_{ecc} /Q_{con} and second to assess the coactivation of hamstrings and quadriceps during isokinetic knee flexion/extension. Eight recreational football players (mean ± SD age: 22 ± 2.3 yr; body mass: 85 ± 3.30~kg) volunteered …to participate in this study. Peak concentric and eccentric torque of the hamstrings and quadriceps were measured at 120°/s pre and post fatigue using an isokinetic dynamometer. The fatiguing protocol consisted of 50 maximal concentric knee flexion/extension repetitions. Using surface EMG, peak RMS of the biceps femoris and vastus lateralis were measured in order to calculate muscle coactivation during extension and flexion of the knee. Paired samples t-tests concluded that there was a significant increase in both the conventional ratio (0.75 vs. 1.02) and the DCR (0.88 vs. 1.08) following fatigue. A significant increase in hamstring coactivation during concentric quadriceps muscle actions following fatigue was also observed (18.6 vs. 21.3%. These data contribute to the literature aiding the future development of the DCR and its use in injury prevention and rehabilitation strategies. Show more

Keywords: Injury, coactivation, fatigue, isokinetic

DOI: 10.3233/IES-2009-0348

Citation: Isokinetics and Exercise Science, vol. 17, no. 3, pp. 161-167, 2009

Authors: Bohannon, Richard W.

Article Type: Research Article

Abstract: A retrospective review of patient records was undertaken to establish the responsiveness of measurements of knee extension force obtained by hand-held dynamometry. Of particular interest was a minimal clinically important difference (MCID). A transition of dependence to independence in sit-to-stand was considered clinically important. Patients who experienced such a transition had a mean increase in bilateral knee extension force of 83 N (43%), whereas patients who remained dependent in sit-to stand demonstrated …a decrease in bilateral knee extension force of 7 N (3%). Although a difference of 43% is contextual, it provides the first clue of an MCID in knee extension force indicative of responsiveness for the measurement. Show more

Keywords: Muscle strength, measurement, dynamometry

DOI: 10.3233/IES-2009-0349

Citation: Isokinetics and Exercise Science, vol. 17, no. 3, pp. 169-172, 2009

Authors: Baláš, Jiří | Strejcová, Barbora | Malý, Tomáš | Malá, Lucia | Martin, Andrew J.

Article Type: Research Article

Abstract: The aim of this study was to investigate whether climbing in children leads to the development of upper limb strength and endurance, and changes in body composition. Fifty young climbers aged 10–17 participated in an 8 week climbing program. Metres climbed were used as a factor to assess the effect of climbing. Two groups were ex post formed with a limit of 320 metres climbed. Boys and girls from the group that climbed more metres significantly …increased their performance in bent-arm hang time (boys from 35.1 ± 3.9 s to 48.4 ± 4.4 s; girls from 18.9 ± 3.9 s to 24.4 ± 4.9 s) and grip strength related to body mass (boys from 0.65 ± 0.03 to 0.71 ± 0.03; girls from 0.52 ± 0.03 to 0.57 ± 0.03). Significant changes in the ECM/BCM ratio (extra cellular/body cellular mass) were found in the group that climbed more metres (boys from 0.88 ± 0.10 to 0.85 ± 0.09; girls from 1.00 ± 0.09 to 0.94 ± 0.09). There were no changes found in body fat in either group. The findings suggest that a climbing program with higher volume of metres climbed can influence grip strength, upper body muscular endurance and the amount of relative body cellular mass. Show more

Keywords: Sport climbing, strength, muscular endurance, body composition, children

DOI: 10.3233/IES-2009-0350

Citation: Isokinetics and Exercise Science, vol. 17, no. 3, pp. 173-179, 2009

Authors: van Cingel, Robert | van Melick, Nicky | van Doren, Lieke | Aufdemkampe, Geert

Article Type: Research Article

Abstract: The isokinetic strength of ankle inversion-eversion was twice tested, over a period of one week, by the same examiner in apparently healthy 15 women and 15 men at 30 and 120°/s. Test – retest measurements were examined for 1 and 3 sets of three repetitions. Intraclass correlation coefficients for the highest peak torque out of 1 set of 3 repetitions varied from 0.47–0.82 for men and 0.70–0.94 for women. The ICC for the mean-based PT (the …3 highest PTs out of 3 sets of 3 replicates) ranged 0.74–0.83 for men and 0.80–0.97 for women. Bland-Altman plots have indicated a largely homoscedastic distribution of the test-retest parameters. The standard error of measurement (SEM) varied from 3.6–7.00 Nm for men and 3.3–4.7 Nm for women (highest PT-based) and 2.9–5.7 Nm for men and 1.6–4.0 Nm for women (mean PT-based). Irrespective of either paradigm, there was much dispersion in the ICCs for both genders in other isokinetic parameters such as the time to PT and angle at PT. It is therefore concluded that the only reproducible isokinetic parameter under this test protocol is the peak torque. Show more

Keywords: Isokinetics, ankle, reproducibility of results

DOI: 10.3233/IES-2009-0351

Citation: Isokinetics and Exercise Science, vol. 17, no. 3, pp. 181-188, 2009