Isokinetics and Exercise Science - Volume 20, issue 2

Authors: Lategan, Leon

Article Type: Research Article

Abstract: Background and objectionsAnterior cruciate ligament (ACL) injuries are reportedly more prevalent in women compared to men. The aim of the study was to investigate possible differences in knee muscle activation patterns between men (M) and women (W). Methods: Thirty six women with a mean age of 22.0 years (± 2.3) and 34 men (22.9 years ± 2.6) were recruited on a voluntary basis to participate in the study. Bilateral concentric (CON) and eccentric (ECC) …bilateral isokinetic testing using a Cybex Norm 7000 was conducted at 60°/s and 180°/s. The angle of peak torque at each velocity was used for analysis. Results: No statistically significant differences (p> 0.05) in angle of peak torque between men and women were observed for CON knee extension and CON knee flexion at either 60°/s or 180°/s. There were statistically significant differences for both the left and right legs (p< 0.05) in ECC knee extension angle of peak torque at 60°/s, with women displaying smaller angles of peak torque (M: 58.0° & 56.5°; W: 52.8° & 51.1°. Significant differences (p<0.05) were also observed for ECC knee flexion at 60°/s between men and women, with women having larger angles of peak torque (M: 30.4° & 30.7°; W: 38.2° & 40.2°). At 180°/s, the only statistically significant difference (p< 0.05) observed was for the right leg's ECC knee flexion, where the angle of peak torque was again larger for women (M: 39.2°; W: 47.1°). Conclusions: The significantly different angles of peak torque for ECC knee flexion and extension in women compared to men, may negatively impact their ability to effectively protect the knee joint during landing and cutting, thus putting their ACL at a greater risk for injury. Show more

Keywords: Anterior cruciate ligament, women, men, knee injury, muscle activation

DOI: 10.3233/IES-2012-0443

Citation: Isokinetics and Exercise Science, vol. 20, no. 2, pp. 71-76, 2012

Authors: Suárez-Arrones, Luis J. | Portillo, L. Javier | González-Ravé, José M. | Muñoz, Victor E. | Sanchez, Francisco

Article Type: Research Article

Abstract: The aim of this study was to analyze the movement patterns and physiological demands of an international level male Rugby Union team. Fourteen samples of running performance, exercise intensity, acceleration and impacts to the body were taken over the course of 3 games using a GPS device. The players covered a mean distance of 6162 m per game, with the forwards covering 5853 m and the backs 6471 m at average speeds throughout the games of 4.3 km/h and …4.77 km/h, respectively. For more than 75.5% and 68.5% of the game forwards and backs, respectively, were exposed to heart rates above 80% of their maximal heart rate. The player's time-related work to rest ratio was 1:0.8. Rugby Union can be considered a high intensity intermittent team sport with many and varied non-locomotor activities and actions that occur during the playing of matches. These actions and activities greatly increase the exercise intensity but are registered as being low speed running. Each position in the field requires specific physiological demands. Show more

Keywords: Competition, elite, rugby, GPS

DOI: 10.3233/IES-2012-0444

Citation: Isokinetics and Exercise Science, vol. 20, no. 2, pp. 77-83, 2012

Authors: Comuk, Nilay | Erden, Zafer

Article Type: Research Article

Abstract: The purpose of this study was to determine the effect of muscular and cardiovascular endurance and lower extremity strength on axel jump in figure skaters. Twenty national female professional figure skaters (age, 18.85 ± 2.70 years) at junior (n=10) and senior (n=10) competitive levels, performing figure skating at least for 5 years volunteered for the invastigation. Skaters were divided into two groups as being able to perform double axel (double axel group, n=9), and not being …able to perform double axel (non double axel group, n=11). All skaters were evaluated on isometric muscular and cardiovascular endurance tests. One Minute Sit-Ups, 1 Minute Modified Push-Ups, Biering-Sorensen muscular endurance tests and Cooper 12-Minute Run/Walk cardiovascular endurance test were used to evaluate endurance. Jumping performance was evaluated by attaining axel jumping in the presence of a referee. Number of revolution that a skater succeeded was reported. The double axel group performed significantly better in the 12-Minute Run/Walk cardiovascular endurance, 1 Minute Modified Push-Ups, Biering-Sorensen muscular endurance tests, right knee extension and right and left plantar flexion. This study indicates that cardiovascular and muscular endurance as well as strength have an effect on performing double axel jump. Conditioning for figure skaters to enhance performance of jumping skill should include these components. Show more

Keywords: Performance, athlete, ice skating, winter sports, endurance, strength

DOI: 10.3233/IES-2012-0445

Citation: Isokinetics and Exercise Science, vol. 20, no. 2, pp. 85-90, 2012

Authors: Flansbjer, Ulla-Britt | Lexell, Jan

Article Type: Research Article

Abstract: The aim of this study was to assess knee extensor and flexor muscle torque in individuals with hemiparesis after stroke and determine the relationship with muscle tone. Fifty individuals (mean age 58 ± 6.4 years), 6 to 48 months after stroke, participated in the study. Maximal concentric knee extension and flexion torque at 60°/s and 120°/s and maximal eccentric knee extension contractions at 60°/s were measured with a Biodex dynamometer. Muscle tone was assessed with the …modified Ashworth Scale. The relative weakness in the paretic knee muscles ranged from 30% to 42% and was greater for the flexors and at higher velocities (p< 0.05). The knee flexion/extension torque ratio in the non-paretic lower limb was 0.53 for both velocities and significantly lower (p< 0.01) for the paretic lower limb (0.44 at 60°/s and 0.39 at 120°/s). The eccentric/concentric ratio in the paretic lower limb (1.66) was significantly higher (p< 0.05) than in the non-paretic lower limb (1.31). Concentric torque in the paretic lower limb was significantly correlated (p< 0.05) with muscle tone. In conclusion, post-stroke weakness of the knee muscles was most prominent in the flexors and at higher velocities, whereas eccentric strength seemed to be preserved. Strength was also associated with the spasticity that can occur after stroke. This post-stroke muscle weakness pattern could be of importance for gait performance and should therefore be accommodated when planning rehabilitation interventions. Show more

Keywords: Stroke, muscle strength, muscle strength dynamometers, muscle tonus

DOI: 10.3233/IES-2012-0446

Citation: Isokinetics and Exercise Science, vol. 20, no. 2, pp. 91-97, 2012

Authors: Bini, Rodrigo Rico | Senger, Daniel | Lanferdini, Fabio | Lopes, Andre Luiz

Article Type: Research Article

Abstract: Workload and experience in cycling have been suggested as factors influencing joint kinematics in cycling. The aims of our study were to (1) compare cyclists and non-cyclists lower limb kinematics and (2) to assess the effects of different workload levels on joint kinematics of cyclists and non-cyclists. Fifteen male athletes with experience in road cycling and triathlon competitions and fourteen male non-athletes volunteered to take part in the study. They performed an incremental test to exhaustion …using their own bicycles (athletes) or a road bicycle set for their body dimensions (non-athletes). Right sagittal plane kinematics and gases exchanges were collected during the test. Ventilatory thresholds related workloads were defined for offline analysis of lower limb joint kinematics. Greater ankle range of motion was observed for athletes (17%) and non-athletes (25%) at maximal workload level compared to lower workload levels. Greater forward body position was observed for athletes (∼ 12%) and non-athletes (5–7%). Smaller hip flexion was observed for non-athletes compared to athletes (7%). Sub maximal workload level did not substantially affect lower limb joint kinematics. Similar lower limb joint motion between athletes and non-athletes suggests that changes in road cycling training may not result in different joint kinematics. Show more

Keywords: Workload, pedaling technique, cycling performance, ventilatory threshold

DOI: 10.3233/IES-2012-0447

Citation: Isokinetics and Exercise Science, vol. 20, no. 2, pp. 99-105, 2012

Authors: Leunkeu, Angeline Nsenga | Ahmaidi, Said

Article Type: Research Article

Abstract: The aim of the study was to document the longitudinal changes from one year to the next in knee extensor muscle strength and function and in cardiorespiratory demand during an isometric test in children with cerebral palsy (CP). Ten children with CP (GMFC I and II) and ten able-bodied children underwent a quadriceps strength and endurance assessment on an isokinetic dynamometer. Maximal voluntary isometric torque in the children with CP in the initial test was significantly …lower than in controls (p=0.0007) and did not change significantly over the year. No significant difference was found between the two groups for the initial static endurance measure (p=0.93); it did not change significantly after one year in the children with CP (p=0.74). Oxygen cost was significantly greater in the group with CP than in the control group (p< 0.01) and there was a further significant increase in the oxygen cost for the CP group 12 months later (p<0.01). Ventilation and heart rate at exhaustion were also significantly lower in children with CP than controls in the initial test (p=0.0001 and p=0.009, respectively). The persisting muscle weakness and the increase in oxygen cost over time may in part have resulted from inactivity and misuse of muscle. Secondary adaptive soft tissue changes affecting the development of muscle may prevent the increases in strength and endurance normally associated with growth and development. Show more

Keywords: Isometric test, cerebral palsy, cardiorespiratory data, longitudinal measurement

DOI: 10.3233/IES-2012-0448

Citation: Isokinetics and Exercise Science, vol. 20, no. 2, pp. 107-113, 2012

Authors: Burfeind, Kevin | Hong, Junggi | Stavrianeas, Stasinos

Article Type: Research Article

Abstract: The purpose of this study was to compare the neuromuscular fitness profiles of male and female NCAA Division III soccer players (D-III). A total of 53 subjects (29 male, 23 female) performed various neuromuscular fitness tests prior to the beginning of a competitive season. Neuromuscular fitness was quantified through single leg balance assessment, time to generate peak torque, peak knee flexion and extension torque, hamstring to quadriceps ratio, and flexibility tests. Test results revealed that females …possessed significantly greater balance ability whereas males possessed increased peak knee extension and flexion torque. Hamstring to quadriceps ratio and flexibility results were not significantly different between genders. Results of time to peak torque tests were in variance with previous studies assessing Division I and professional soccer players. The results of the present study reveal gender differences in neuromuscular fitness in D-III soccer players and that the neuromuscular fitness may differ between D-III and D-I soccer players. Show more

Keywords: Neuromuscular fitness, gender differences, soccer, college sports

DOI: 10.3233/IES-2012-0449

Citation: Isokinetics and Exercise Science, vol. 20, no. 2, pp. 115-120, 2012

Authors: Rebai, Haithem | Zarrouk, Nidhal | Sahli, Sonia | Tabka, Zouhair | Hug, François | Dogui, Mohamed

Article Type: Research Article

Abstract: This study aimed at quantifying maximal voluntary force-generating capacity of the quadriceps femoris and its EMG output after an isokinetic concentric intermittent exercise. Another objective was to find out whether the amount of neuromuscular fatigue was velocity-dependent. Eight males judo players (age: 18.4 ± 1.4 years; height: 1.80 ± 0.03 m; body mass: 77.0 ± 4.2 kg) performed a fatiguing exercise composed of five sets of ten maximal knee extension at …120°/s, with 3min recovery in between. Peak torque (PT) at three angular velocities (60, 120 and 180°/s) and EMG from the vastus lateralis, rectus femoris and vastus medialis were evaluated before and after the fatiguing exercise. EMG was analyzed for root mean square (RMS) and median frequency (MF). The fatiguing exercise induced PT decrement (P< 0.01) irrespective of the test velocity, in conjunction with decreased RMS (P< 0.001) and a decrease in MF (P< 0.01). In addition, although EMG activity demonstrated no velocity effect, the loss of PT after the fatiguing isokinetic intermittent exercise was more pronounced at the lower velocity (P< 0.05). The combination of decreased PT, RMS and MF suggests a reduction of the neural drive under the present fatiguing protocol. Show more

Keywords: Neuromuscular fatigue, torque, electromyography, velocity

DOI: 10.3233/IES-2012-0450

Citation: Isokinetics and Exercise Science, vol. 20, no. 2, pp. 121-128, 2012

Authors: Hedlund, Mattias | Sojka, Peter | Lundström, Ronnie | Lindström, Britta

Article Type: Research Article

Abstract: The aim of this study was to compare the effect of isokinetic contraction mode and velocity on the torque-angle relationship during maximum voluntary elbow flexion in patients with stroke, age-matched healthy subjects and young subjects. To eliminate the effect of torque amplitude differences between subjects and groups, the torque values throughout the ROM were individually normalized to the peak value for each contraction velocity. The results indicate that in stroke patients the normalized torque angle …relationship during the eccentric contractions was better preserved than during concentric contractions. Specifically, during eccentric contractions, stroke patients exhibited a torque-angle relationship that was closer to normal as the test velocity increased. The opposite trend could be seen in concentric contractions where the torque-angle relationship became more divergent from normal with a rise in the velocity. The torque-angle relationships were essentially the same for the control groups, irrespective of contraction mode or velocity. These findings may have significance for loading patterns of resistance training exercises used with stroke patients as such exercises normally are biomechanically designed for normal torque angle relationships. In clinical practice, these findings may partly explain why the strength increases due to resistance training are limited for patients with stroke. Show more

Keywords: Elbow, concentric, eccentric, strength, torque-angle relationship, resistance training

DOI: 10.3233/IES-2012-0455

Citation: Isokinetics and Exercise Science, vol. 20, no. 2, pp. 129-140, 2012

Authors: Yu, Jae-Ho | Lee, Gyu-Chang

Article Type: Research Article

Abstract: This study investigated the effect of core stability training using pilates for 8 weeks on lower extremity muscle strength and postural stability. Participants included 40 healthy people who were randomly allocated to 1 of 2 groups: a core stability training group (CST) (n=20) and a control group (n=20). The CST group received three 60-minute pilates training sessions per week for 8 weeks, whereas the control group did not undergo any training. We measured pre- and post-training …lower extremity muscle strength using isokinetic equipment and postural stability using a balance device. Significant posttest increments in lower extremity muscle strength and postural stability were observed in the CST group (P< 0.05). However, neither of these parameters was significantly improved in the control group. Significant differences in lower extremity muscle strength and postural stability were found between the CST group and the control group after 8 weeks (P< 0.05). These results indicate that pilates core stability training enhances motor performance skills by increasing lower extremity muscle strength and improving postural stability and can prevent musculoskeletal disorders and improve quality of life. Further studies should focus on creating a program combining other trainings for achieving improved core stability and investigating duration of training effect. Show more

Keywords: Core stability, strength, postural stability, pilates

DOI: 10.3233/IES-2012-0462

Citation: Isokinetics and Exercise Science, vol. 20, no. 2, pp. 141-146, 2012

Article Type: Correction

Abstract: Erratum to https://dx.doi.org/10.3233/IES-2011-0395

DOI: 10.3233/IES-2012-0456

Citation: Isokinetics and Exercise Science, vol. 20, no. 2, pp. 147-147, 2012