Isokinetics and Exercise Science - Volume 12, issue 2

Authors: Bardis, C. | Kalamara, E. | Loucaides, G. | Michaelides, M. | Tsaklis, P.

Article Type: Research Article

Abstract: Introduction: There is minimal information in the literature concerning the intramachine reliability of the new Isokinetic dynamometer Con-Trex MJ, and the intermachine reproducibility of this instrument with the Cybex Norm isokinetic dynamometer. Objective: The purpose of this study was to provide some insight with regard to the reproducibility of Con-Trex MJ in measuring the knee muscle performance in flexion and extension (concentric) and to compare the variability of measurement between Con-Trex and Cybex Norm. …Methods: 35 (70 legs) male subjects with no previous history of any knee pathology volunteered for the study. Intramachine reproducibility was evaluated by assessing 30 legs twice on the Con-Trex MJ, within 2 to 7 days, at angular velocities of 60°, 180° and 300°/sec. Intermachine reproducibility was evaluated by assessing 40 legs randomly on the Con-Trex MJ and Cybex Norm within 2 to 7 days at 60° and 180°/sec. Coefficient of variation (CV) was used to determine the reproducibility of repeated measurements at $p< 0.01$. Results: Intra: The variability of measurements of Con-Trex for Peak Torque, was 5.19–5.68% for extension and 4.84–7.33% for flexion depending on the angular velocity. This is acceptable for clinical and research studies. Inter: Between the two Isokinetic devices there was a greater CV for Peak Torque ranging 7.28–9.17% for extension and 8.54–15.84% for flexion. Conclusion: Based on the results of the present study, comparisons of results between the two devices may not be valid. The results for knee flexion and extension measurements at 60° and 180°/sec recorded with Con-Trex were consistently greater than the values recorded with the Cybex Norm. Show more

Keywords: intramachine, intermachine, reproducibility, reliability, isokinetic, dynamometer

DOI: 10.3233/IES-2004-0155

Citation: Isokinetics and Exercise Science, vol. 12, no. 2, pp. 91-97, 2004

Authors: Porter, Gary Keith | Kaminski, Thomas W.

Article Type: Research Article

Abstract: The purpose of this study was to examine varying degrees of knee flexion on isokinetic eversion (E) to inversion (I) strength ratios. Twenty healthy subjects volunteered for this study. Concentric (CON) peak torque (PT) of both ankles (dominant, non-dominant) at three different angles of knee flexion (15°, 30°, 45°) and two different velocities (30°/s, 120°/s) was assessed with ankle plantar flexion maintained at 10°. The E_{CON} :I_{CON} ratios at 30°/s …ranged from 0.87 to 1.04 across all three angles, while those at 120°/s ranged from 0.86 to 1.00 indicating no differences in ratios between knee-flexion angles or ankles. However, there was a trend in lower ratios evident in the dominant compared to non-dominant ankles. These results suggest that subjects may be positioned with knee flexion angles ranging from 15° to 45° without influencing the outcome of the ankle eversion and inversion strength measurements. Show more

DOI: 10.3233/IES-2004-0156

Citation: Isokinetics and Exercise Science, vol. 12, no. 2, pp. 99-104, 2004

Authors: Okamoto, Takanobu | Masuhara, Mitsuhiko | Ikuta, Komei

Article Type: Research Article

Abstract: The purpose of this study was to investigate the effect of eccentric contraction velocity on quadriceps oxygen dynamics. Fifteen healthy male volunteers were tested eccentrically at 60 and 180°/s for a duration of 30 s. A probe for near infrared spectroscopy was placed on the rectus femoris allowing determination of muscle oxygenation (MO) levels and blood volume (BV). Higher MO and BV levels were observed at higher compared to the lower velocity. These results suggest that …during eccentric knee extension at slow muscle contraction velocity, mechanical compression directed toward blood vessels is augmented resulting in blood flow disturbances and further evolving into hypoxic state within muscle tissues. Show more

DOI: 10.3233/IES-2004-0157

Citation: Isokinetics and Exercise Science, vol. 12, no. 2, pp. 105-109, 2004

Authors: Baur, Heiner | Divert, Caroline | Hirschmüller, Anja | Müller, Steffen | Belli, Alain | Mayer, Frank

Article Type: Research Article

Abstract: Differences in lower extremity movement characteristics are stated as a reason for overuse injuries. The causal assignment of biomechanical quantities to the onset of complaints is still subject of debate in gait analysis. The purpose of this study was therefore to compare biomechanical gait characteristics by means of plantar pressure distribution (PPD), EMG and ground reaction forces (GRF) in healthy runners and in runners with chronic Achilles tendon complaints (AT). Fourteen healthy runners and 8 runners …with AT were examined at 12 km/h. Surface EMG, in-shoe PPD and GRFs were evaluated on a treadmill mounted on force transducers. Subjects ran barefoot and with a reference shoe in random order. EMG time and amplitude quantities, characteristics of the path of the center of pressure (CoP), vertical and a-p forces and impulses were extracted. In AT no differences in CoP-characteristics between barefoot and reference shoe were observed, compared to corresponding significant differences in the control group. Compared to the AT group, the control subjects had a higher activity EMG-amplitudes in the extensor loop during weight acceptance phase, a higher braking impulse and a lower pushing impulse. It is thus concluded that healthy runners differ from AT patients in terms of movement characteristics especially in running. Show more

Keywords: barefoot and shod running, electromyography, gait analysis, ground reaction forces, overuse injury, plantar pressure distribution

DOI: 10.3233/IES-2004-0161

Citation: Isokinetics and Exercise Science, vol. 12, no. 2, pp. 111-116, 2004

Authors: Stefańska, Małgorzata

Article Type: Research Article

Abstract: Objective: To determine the force-velocity characteristics (F-v) of upper limb muscles and specify the muscle group which has a predominant influence on the global F-v characteristics of the limb. Subjects and methods: 30 healthy young men participated in this study which consisted of two experiments. In the first the moment developed by flexors and extensors of shoulder, elbow and radio-carpal joints at angular velocities ranging 0–300°/s was measured isokinetically. In the second experiment global …F-v characteristics were assessed statically and dynamically. Results: Elbow extensors had a predominant impact on the shape of the global F-v characteristics of the examined limb. Conclusions: The force-velocity characteristics provide comprehensive information regarding the capacity of the examined muscle groups. This information is of value in setting target scores for total upper limb strength in the context of specific habitual activities such as chair rise. Show more

Keywords: upper limb, isokinetics, force-velocity characteristics, peak torque

DOI: 10.3233/IES-2004-0163

Citation: Isokinetics and Exercise Science, vol. 12, no. 2, pp. 117-125, 2004

Authors: Malicka, Iwona

Article Type: Research Article

Abstract: The aim of this research was to determine strength-velocity characteristics of trunk flexors and extensors in women after mastectomy and to compare these with the corresponding parameters derived from a matched group of healthy women. The study comprised of 96 women divided into three groups: 32 women after mastectomy and undergoing rehabilitation, 34 women after mastectomy but without rehabiliation and 30 healthy women. The tests were conducted at 60, 90 and 120°/s. Women after mastectomy, who …did not take part in rehabilitation, had on average a 40% strength deficiency compared to the control group, the most severe deficiency observed at 60°/s. These women achieved only 57% of the healthy women capability for extensor muscles and 49% for flexor muscles of spine. Women undergoing rehabilitation performed significantly better despite the radical oncological treatment. At 60°/s they achieved 151% of a capability of the healthy women for extensor muscles and 123% for flexor muscles of trunk. Show more

Keywords: breast cancer, physiotherapy, trunk muscles, functional dynamometry

Citation: Isokinetics and Exercise Science, vol. 12, no. 2, pp. 127-133, 2004

Authors: Wang, Hsing-Kuo | Juang, Lin-Guey | Lin, Jau-Jia | Wang, Tyng-Guey | Jan, Mei-Hwa

Article Type: Research Article

Abstract: The objective of this study was to determine whether arm dominance or gender differences of shoulder mobility and strength exist in elite junior volleyball players. The range of shoulder motion and isokinetic muscle strength in concentric and eccentric internal and external rotation at speeds of 60°/sec and 180°/sec in both dominant and non-dominant shoulders were measured in eleven boys and twelve girls who played for the Taiwanese national junior volleyball team during …the 2001–2002 season. Results showed that there were effects of both dominance and gender on the range of shoulder internal rotation p=0.001 and 0.02 respectively). In the boys, the range of motion of internal rotation on the dominant side was less than that of the non-dominant side (p=0.000). An effect of gender was also demonstrated in the strength test (p=0.000). The boys showed greater shoulder strength than the girls at both speed tests (p=0.000), except for the internal rotational concentric and eccentric strength of the dominant arm at 180°/sec tests (p=0.02 and 0.21). The side-to-side (arm dominance) difference of mobility in boys may indicate a mobility loss in these players. Further studies are suggested to analyze the relationship between mobility loss and mobility-related injuries of young players. Show more

Keywords: isokinetic strength, adolescent athletes

DOI: 10.3233/IES-2004-0165

Citation: Isokinetics and Exercise Science, vol. 12, no. 2, pp. 135-141, 2004

Authors: De Ste Croix, M.B.A. | Deighan, M.A. | Armstrong, N.

Article Type: Research Article

Abstract: The aim of this study was to examine the age and sex associated development of time to peak torque (TPT) of the knee and elbow extensors and flexors. 137 subjects participated in this study consisting of three groups aged 9/10 y, 16/17 y and 21+ y. Isokinetic concentric knee and elbow extension and flexion were measured using a calibrated Biodex system 3 and TPT was determined. ANOVA identified significant (p < 0.05) interaction effects for stature …and body mass. A main effect for group for knee extension TPT (range 0.20–0.26 s) and elbow flexion TPT (range 0.33–0.40 s) was identified. For elbow flexion the 16/17 y-olds demonstrated significantly faster TPT than the 9/10 y-olds and adults. No significant interaction or main effects for knee flexion (range 0.0.19–0.23 s) or elbow extension (range 0.40–0.44 s) were observed. Pearson product moment correlation coefficients identified no significant relationship between TPT and peak torque for knee and elbow extensors and knee flexors in all groups. A significant negative correlation (p < 0.05) was found for the elbow flexors for both 9/10 y-olds and adults for females but not males. To conclude, no sex differences in TPT of the knee and elbow extensor and flexor muscles were found. Age related changes in TPT appear to be muscle group and muscle action specific and highlight the caution one has to exercise in making assumptions between muscle groups and actions. Show more

DOI: 10.3233/IES-2004-0166

Citation: Isokinetics and Exercise Science, vol. 12, no. 2, pp. 143-148, 2004

Authors: Dupuis, C. | Tourny-Chollet, C. | Delarue, Y. | Beuret-Blanquart, F.

Article Type: Research Article

Abstract: Objective: To determine the strength ratios in the shoulder rotator muscles of teenage baseball players, using a new test position. Methods: Ten asymptomatic baseball players of the French cadet team (15.87 ± 0.80 yr) underwent dynamic isokinetic strength assessment of the shoulder rotators at two angular velocities: 90 and 180°.s^{-1} . The peak torque of the internal rotators (IR) and external rotators (ER) was recorded. One conventional ratio and two dynamic ratios were …determined at each angular velocity. The mean group values were statistically analyzed. Results: Mean ER peak torque was significantly higher in the dominant than in the non-dominant arm at both velocities (p < 0.05). The dynamic ratio (ER conc/IR ecc) was significantly higher in the dominant than in the non-dominant arm (p < 0.01). In the same position, baseball players had higher conventional and dynamic ratios (IR conc/ER ecc) than those reported in the literature for sedentary subjects. Conclusion: Intensive baseball practice affects the shoulder rotator muscles. The IR values indicated greater strength than in sedentary subjects. The difference in ER between the dominant and non-dominant arms underlines the effect of pitching technique and suggests the need for further investigations. Show more

Keywords: shoulder rotator, baseball, teenagers, scapular plane, conventional and dynamic ratios

DOI: 10.3233/IES-2004-0167

Citation: Isokinetics and Exercise Science, vol. 12, no. 2, pp. 149-157, 2004

Article Type: News

Abstract: Article without abstract.

Citation: Isokinetics and Exercise Science, vol. 12, no. 2, pp. 159-166, 2004