Isokinetics and Exercise Science - Volume 18, issue 4

Authors: Warren, Barbara L. | Longwell, Kristin K.

Article Type: Research Article

Abstract: The purpose of the study was to evaluate the effect of rest period on peak torque in females. Thirty college-aged females (n = 15 collegiate athletes and n = 15 recreational athletes) performed three practice sessions and four experimental sessions using a knee flexion/extension protocol on a CYBEX NORM isokinetic dynamometer. Each session began with a five minute warmup on a cycle ergometer after which the subjects performed four maximal repetitions of knee extension at five …isokinetic velocities, 60, 120, 180, 240, and 300° · sec^{-1} with randomly assigned rest periods of 15, 60, 180, or 300 seconds between velocity sets while knee flexion was held constant at 300°· sec^{-1} . Peak torque was recorded for each trial. Data were analyzed using a 4 (rest) × 5 (velocity) repeated measures ANOVA (p < 0.05). There were no significant differences in peak torque between any of the rest periods. It was concluded that in females a 60 second rest is adequate for muscle recovery when executing four maximal repetitions. Show more

Keywords: Isokinetic testing, fatigue, rest period, knee extension

DOI: 10.3233/IES-2010-0381

Citation: Isokinetics and Exercise Science, vol. 18, no. 4, pp. 179-184, 2010

Authors: Bohannon, Richard W.

Article Type: Research Article

Abstract: This retrospective study examined the adequacy of manual muscle testing (MMT) as a measure of knee extension force among home-care patients. The knee extension strength of 31 patients was measured by MMT, hand-held dynamometry (HHD), and the five-repetition sit-to-stand-test (FRSTST). Although most patients were identified as weak by MMT, neither the sensitivity nor the specificity of MMT relative to HHD or FRSTST justifies its use as a sole measure of muscle strength among home care patients.

Keywords: Muscle strength, measurement, validity

DOI: 10.3233/IES-2010-0382

Citation: Isokinetics and Exercise Science, vol. 18, no. 4, pp. 185-187, 2010

Authors: Almosnino, Sivan | Sled, Elizabeth A. | Costigan, Patrick A. | Chalmers, Alison | Stevenson, Joan M.

Article Type: Research Article

Abstract: Isokinetic assessment of knee extensors muscle group function in patients suffering from knee osteoarthritis has exclusively been achieved using time-domain based variables. While useful, these analyses do not quantify the conspicuously irregular moment-time pattern exhibited by the involved knee when compared to the contralateral knee. The purpose of this investigation was to assess whether the frequency content of the isokinetic curve can quantify this latter phenomenon. Thirty two patients with knee osteoarthritis participated in …this study. Each participant performed 5 maximal concentric knee extensions bilaterally at 60°/s using an isokinetic dynamometer. For each time-domain extension curve, the power spectrum was calculated via Fast Fourier Transform and the maximum frequency content value contained within 99% of total signal power was extracted. Of the 32 participants, 26 exhibited higher frequency contents in the isokinetic curves obtained from their involved knee (p= 0.002, effect size =0.35). The results suggest that the frequency content of isokinetic moment-time curves may provide useful quantitative information regarding the smoothness of moment production, and as such, may be used in conjunction with traditional time-domain variables in the assessment of knee extensors function in patients suffering from knee osteoarthritis. Show more

DOI: 10.3233/IES-2010-0383

Citation: Isokinetics and Exercise Science, vol. 18, no. 4, pp. 189-192, 2010

Authors: Behrens, Martin | Mau-Möller, Anett | Laabs, Henrike | Felser, Sabine | Bruhn, Sven

Article Type: Research Article

Abstract: The purpose of the study was to investigate the effects of a combined sensorimotor – resistance training on muscle strength and neuromuscular activation of selective muscles of the right ankle joint. Both treatments were performed successively in each training session. Seven short track speed skaters participated in the study. The training was performed twice a week for 12 weeks. Maximum peak torque during inversion/eversion, the associated neuromuscular activation of soleus and peroneus longus as well as …eversion/inversion ratio were measured in a pre- and post-test, respectively. After the training the athletes revealed a significantly increased maximum peak torque during inversion (17.47 ± 4.37N · m vs. 23.57 ± 3.58N ˙ m; p =0.006) associated with a significantly increased root mean square of the EMG signal in the soleus (12.42 ± 6.09mV vs. 24.00 ± 9.37mV; p = 0.009). The eversion/inversion ratio was significantly decreased after training (0.96 ± 0.12 vs. 0.77 ± 0.11; p = 0.034). Eversion training adaptations were lower than inversion training adaptations probably due to the fact that resistance training did not contain an exercise for peroneus longus. Based on these the combined sensorimotor-resistance training is an attractive option for athletes where maximum strength, active joint stabilization and postural control plays a decisive role. Show more

Keywords: Sensorimotor training, resistance training, maximum peak torque, ankle joint

DOI: 10.3233/IES-2010-0384

Citation: Isokinetics and Exercise Science, vol. 18, no. 4, pp. 193-200, 2010

Authors: Salli, Ali | Sahin, Nilay | Baskent, Akin | Ugurlu, Hatice

Article Type: Research Article

Abstract: We aimed to investigate the effects of isometric and combined concentric-eccentric (C-E) isokinetic types of exercise applied to the knee muscles in patients with knee osteoarthritis (OA) in an attempt to identify which type of exercise would be most effective in terms of pain relief, functional status, quality of life, and muscular strength. This was a controlled trial in which 71 patients were randomized into three groups. The first group was assigned to C-E, the second …group to isometric isokinetic exercises, while the third, control group, was only given paracetamol. A visual analog scale for pain, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and Short From-36 (SF-36) for functional status and quality of life, and the isokinetic test for muscular strength were evaluated. Significant improvements were recorded in all groups for pre and post-treatment pain, the WOMAC and the SF-36 (P< 0.001). Among the exercise groups, improvement was significantly better in the C-E, isokinetic exercise group as compared with the isometric exercise group (P < 0.001). Isokinetic exercises are recommended as a treatment modality. However, the long-term effects of these exercises on pain and osteoarthritis progression need to be investigated. Show more

Keywords: Osteoarthritis, knee, quality of life, exercise, functional status, analgesic

DOI: 10.3233/IES-2010-0385

Citation: Isokinetics and Exercise Science, vol. 18, no. 4, pp. 201-209, 2010

Authors: Brito, João | Figueiredo, Pedro | Fernandes, Luís | Seabra, André | Soares, José M. | Krustrup, Peter | Rebelo, António

Article Type: Research Article

Abstract: The purpose of this study was to evaluate whether FIFA's Medical Assessment and Research Centre (F-MARC) injury prevention programme, "The 11+", improves isokinetic strength of the knee extensor and flexor muscles in sub-elite soccer players. Twenty players aged 22.3 ± 4.2 yr performed "The 11+" 3 times a week for 10 weeks. Isokinetic measurements were performed on the hamstrings and quadriceps muscles on both lower extremities at concentric 60 and 180°/s and eccentric 30°/s. The peak …torque (PT) as well as conventional and dynamic control ratios (DCR) were calculated. Hamstrings PT in the non-dominant limb increased by 14.6%, 15.0% and 14.3% during the above contractions/velocities, respectively (p< 0.05). In the dominant limb the concentric PT of the quadriceps increased by 6.9% (60°/s) and 8.3% (180°/s) whereas that of the hamstring increased by 20.4% (60°/s), (p< 0.05). The training programme significantly improved the conventional H/Q ratio at 60°/s by 14.8{\%} and the DCR by 13.8% in the non-dominant limb (p< 0.05). Therefore, the "The 11+" training programme appears to be adequate and effective for soccer training and conditioning by improving strength and muscle balance around the knee joint. Show more

Keywords: Soccer, training, muscle balance, hamstrings

DOI: 10.3233/IES-2010-0386

Citation: Isokinetics and Exercise Science, vol. 18, no. 4, pp. 211-215, 2010

Authors: Houweling, Taco A.W. | Hamzeh, Maher A.

Article Type: Research Article

Abstract: The aim of this study was to determine the reliability of five positions of alignment of the knee joint with the axis of a Cybex Norm isokinetic dynamometer. Seventeen physically active males volunteered for this study. The knee joint was positioned in five xy-plane coordinates from the rotational axis of the dynamometer (cm): (0,0); (2,0); (4,0); (0,-2) and (0;-4). Repeated measures Analysis of Variance (ANOVA) and Ratio Limits of Agreement (RLOA) were calculated for …knee extension and flexion peak torque in all positions of alignment. The ANOVA demonstrated no significant differences in peak torque for knee extension (F(4,64) = 1.813, P > 0.05) and significant differences in peak torque for knee flexion (F(4,64) =5.760, P < 0.05). The RLOA showed a standard bias ranging from −7 to −12% and systematic error ranging from 21 to 29% for knee flexion. Knee extension peak torque did not significantly change when the knee joint was misaligned with the axis of the dynamometer. However, knee flexion peak torque was significantly affected when the knee was moved away both horizontally and vertically from the centre of the axis of the dynamometer. Show more

Keywords: Ratio Limits of Agreement, RLOA, isokinetic testing, knee joint alignment, cone method, rotational axis

DOI: 10.3233/IES-2010-0387

Citation: Isokinetics and Exercise Science, vol. 18, no. 4, pp. 217-221, 2010

Authors: Siatras, Theophanis A. | Douka, Ioanna D. | Milosis, Dimitrios C.

Article Type: Research Article

Abstract: This study aimed to determine feasibility and reproducibility of muscular strength measurements in young gymnasts, using hand-held dynamometry in gymnastics-specific body positions. A group of 32 male and female young gymnasts 8–11 years-old, performed different strength tests using a Nicholas Manual Muscle Tester (NMMT). The measurements were collected in 4 major muscle groups (shoulder flexors and extensors, hip flexors and extensors) at 22 different joint angular positions, with the active elbow or knee joint in full …extension. The maximal strength was obtained by placing the NMMT in a distal forearm or shank position, with the gymnast in supine or prone position stabilized on a vault. A Myrin goniometer, attached on the sagittal plane near elbow or knee joint, was used to specify the shoulder and hip joint angular positions. In the majority of the measurements (18 out of 22 angular positions) the intra-class correlation coefficients revealed a good level of test-retest reliability (R = 0.80–0.88). In four cases (3 in shoulder flexors and 1 in shoulder extensors) intra-class reliability was fair, with R-values ranging from 0.70 to 0.78. The low coefficients of variation and standard errors of measurements affirmed the reproducibility of measurements. In conclusion, this study showed the feasibility and the reproducibility of shoulder and hip flexor and extensor muscles maximal strength measurements using NMMT in gymnastics-based settings. Show more

Keywords: Gymnasts, force, reliability, NMMT, shoulder muscles, hip muscles

DOI: 10.3233/IES-2010-0388

Citation: Isokinetics and Exercise Science, vol. 18, no. 4, pp. 223-234, 2010

Authors: Bohannon, Richard W. | Bubela, Deborah J. | Magasi, Susan R. | Wang, Ying-Chih | Gershon, Richard C.

Article Type: Research Article

Abstract: Although the validity of the sit-to-stand (STS) test as a measure of lower limb strength has been questioned, it is widely used as such among older adults. The purposes of this study were: 1) to describe five-repetition STS test (FRSTST) performance (time) by adolescents and adults and 2) to determine the relationship of isometric knee extension strength (force and torque), age, gender, weight, and stature with that performance. Participants were 111 female and 70 male (14–85 …years) community-dwelling enrollees in the NIH Toolbox Assessment of Neurological and Behavioral Function. The FRSTST was conducted using a standard armless chair. Knee extension force was measured using a belt-stabilized hand-held dynamometer; knee extension torque was measured using a Biodex dynamometer. The mean times for the FRSTST ranged from 6.0 sec (20–29 years) to 10.8 sec (80–85 years). For both the entire sample and a sub-sample of participants 50–85 years, knee extension strength (r= −0.388 to −0.634), age (r=0.561 and 0.466), and gender (r=0.182 and 0.276) were correlated significantly with FRSTST times. In all multiple regression models, knee extension strength provided the best explanation of FRSTST performance, but age contributed as well. Bodyweight and stature were less consistent in explaining FRSTST performance. Gender did not add to the explanation of FRSTST performance. Our findings suggest, therefore, that FRSTST time reflects lower limb strength, but that performance should be interpreted in light of age and other factors. Show more

Keywords: Muscle strength, measurement, mobility, aging

DOI: 10.3233/IES-2010-0389

Citation: Isokinetics and Exercise Science, vol. 18, no. 4, pp. 235-240, 2010

Authors: Skurvydas, Albertas | Brazaitis, Marius

Article Type: Research Article

Abstract: The aim of this study was to test the hypothesis that intraindividual variability in isokinetic knee extension/flexion relates positively to muscle fatigue, i.e., the less the muscle fatigue during exercise, the greater is the variability of torque fluctuation. Twelve healthy males performed 100 continuous knee extensions and flexions with maximal intensity at 180°/s. The main findings were: 1) the knee extension muscle exhibited more fatigue and less intraindividual variability than the knee …flexion muscles; 2) intraindividual variability in knee extension (SD for torque fluctuation in 100 repetitions) relates closely to fatigue. We conclude that intraindividual variability in isokinetic knee-extension torque relates inversely to muscle fatigue. Show more

Keywords: Isokinetic knee extension and flexion, muscle fatigue, intraindividual variability

DOI: 10.3233/IES-2010-0394

Citation: Isokinetics and Exercise Science, vol. 18, no. 4, pp. 241-246, 2010