Isokinetics and Exercise Science - Volume 21, issue 1

Authors: Nogueira, Felipe Romano Damas | Conceição, Miguel Soares | Vechin, Felipe Cassaro | Junior, Edson Manoel Mendes | Rodrigues, Guilherme Fernando Couto | Fazolin, Marcio Aparecido | Chacon-Mikahil, Mara Patricia Traina | Libardi, Cleiton Augusto

Article Type: Research Article

Abstract: The velocity at which eccentric exercise is performed may be a factor in the extent of muscular damage. However, studies differ regarding the exercise velocity that promotes greater muscle damage. The purpose of this review was to analyze studies that looked into at least two different eccentric exercise velocities and verified markers of muscle damage. Relevant studies for this review were identified and the methodological quality of each study was calculated based on the Physiotherapy Evidence …Database (PEDro) scale. Twelve studies were included herein. The mean PEDro rating was 6.67, ranging from 5 to 7. Seven studies reported that the faster eccentric exercise velocity induced greater muscle damage. Four studies showed no differences between velocities and a single study has indicated a greater magnitude of muscle damage after slow eccentric exercise. Therefore, it seems that fast eccentric exercise may indeed be associated with greater muscle damage even though exercise velocity per se is not the main factor involved in eccentric exercise-induced muscle damage in both animal and human models. Show more

Keywords: Resistance training, muscle strength, creatine kinase, eccentric exercise

DOI: 10.3233/IES-2012-0465

Citation: Isokinetics and Exercise Science, vol. 21, no. 1, pp. 1-9, 2013

Authors: Salci, Yasar | Yildirim, Ahmet | Celik, Ozgur | Ak, Emre | Kocak, Settar | Korkusuz, Feza

Article Type: Research Article

Abstract: Hamstring training involving eccentric loading is an important protective factor in hamstring injuries. However, the effect of this mode of training on lower extremity loading in landing maneuver performance is unknown. The purpose of this study was to examine variations in eccentric hamstring strength after 10-weeks training program and the possible changes in landing kinetics. Twenty five recreational female athletes were voluntarily assigned to the Nordic Hamstraing Strength Training (N=13) or control …groups (N=12). The training group performed 10-weeks eccentric hamstring strength training program. Baseline measures of landing kinetics were collected using a force plate while strength data was evaluated using an isokinetic dynamometer. Results indicated that NHST group increased their eccentric hamstring strength (pre=2.34 ± 0.28, post=2.57 ± 0.25 Nm/kgbw; p < 0.05) after training program albeit without changes in the dynamic control ratio. There were also significant decreases in peak anterior-posterior ground reaction force (PAPGRF; pre=1.14 ± 0.21 BW, post=0.85 ± 0.27 BW; p< 0.05) and peak vertical ground reaction force (PVGRF; pre=6.27 ± 1.00 BW, post=5.34 ± 1.01 BW; p < 0.05) scores for NHST group. The present study supports the positive effect of eccentric hamstring strength in altering landing kinetics in order to decrease the applied forces. Show more

Keywords: Isokinetic strength, eccentric training, kinetics

DOI: 10.3233/IES-2012-0466

Citation: Isokinetics and Exercise Science, vol. 21, no. 1, pp. 11-18, 2013

Authors: Park, Jae-Seok | Oh, Hye-Won | Park, Eun-Kyung | Ko, Il-Gyu | Kim, Sung-Eun | Kim, Jae-Deung | Jin, Jun-Jang | Jee, Yong-Seok

Article Type: Research Article

Abstract: The purpose of this study was to investigate the effects of a 12-week rehabilitation program on functional scores and isokinetic torques of the knee joint in patients with an arthroscopic excision to the medial plica. Twenty-eight young individuals 16 men and 12 women aged 20.4 (± 3.21) and 21.0 (± 1.41) years, respectively. The independent variables in this study were knee sides (involved and uninvolved) and times (pre-test and post-test). The rehabilitation program …consisted of physical and exercise therapies. The latter composed of a warm-up, work-out, and cool-down. The work-out was followed by 1^{st} phase (1 day ∼ 2 weeks), 2^{nd} phase (2∼6 weeks), and 3^{rd} phase (6∼12 weeks). The results indicate that 12 weeks post-operatively the Lyslome and Tegner scores were almost fully normalized. Furthermore, both score and level which related to knee discomfort and functional activity were improved within the abovementioned program compared to a 6-week rehabilitation program. Especially, the Lysholm knee score and Tegner activity levels of female group were higher than those of male group around 12 weeks. Such a result suggest that the both scores in the male group were pitched at too low levels compared to those of female group at the baseline. However, the scores of male group improved and were close to the levels of female group after 12 weeks. The isokinetic extensor absolute and normalized PT at 180°/s in the involved side of both groups, were significantly lower compared to the sound side at 6 week but were normalized at the termination of the program. At 60°/s the findings of the male group were still not significant. We think that these results were affiliated with pre-status of males' symptom or activity level. However, in spite of the inter-gender differences there was a general improvement following 12 weeks. It is concluded that a 12-week rehabilitation program can reduce knee discomfort, improve knee functional activity, and enhance isokinetic torques of the major muscles following excision of the medial plica. Show more

Keywords: Knee discomfort, functional activity, peak torque, peak torque % body weight

DOI: 10.3233/IES-2012-0467

Citation: Isokinetics and Exercise Science, vol. 21, no. 1, pp. 19-28, 2013

Authors: Juárez Santos-García, D. | González-Ravé, J.M. | Legaz Arrese, A. | Portillo Yábar, L.J. | Clemente Suárez, V. J. | Newton, R.U.

Article Type: Research Article

Abstract: The aim of this study was to examine the acute effects of two resistance exercises on 25 m freestyle swimming performance. Twenty-eight regional and national male swimmers volunteered and were randomly assigned to one of three groups: Resistance Swimming Group (RS): (n=9; 16.2 ± 3.8 yr), Elastic Band Group (EB): (n=9; 15.9 ± 4.0 yr.), and Control Group (C) (n=10; 15.7 ± 2.2 yr). Swimmers completed a 25 m swim trial at baseline. Subsequently, RS performed …resisted crawl swimming with 30% of maximum load (1RM) in a power rack for 12 m and 30 seconds later a 25 m maximal swim trial. EB performed 10 seconds of arm freestyle strokes with elastic bands and 30 seconds later a 25 m maximal swim trial. C performed only the second 25 m maximal swim trial. Each group repeated this protocol four times, with two minutes of rest between repetitions. A two-way ANOVA revealed no significant differences in 25 m swimming times between groups for any of the repetitions performed, and there were no significant differences in 25 m swimming times between the repetitions within each group. The results showed that the resistance exercises performed in this study before the 25 m swim trials did not affect swimming times. Show more

Keywords: Power, strength, swimmers

DOI: 10.3233/IES-2012-0468

Citation: Isokinetics and Exercise Science, vol. 21, no. 1, pp. 29-35, 2013

Authors: Akins, Jonathan S. | Longo, Peter F. | Bertoni, Maurizio | Clark, Nicholas C. | Sell, Timothy C. | Galanti, Giorgio | Lephart, Scott M.

Article Type: Research Article

Abstract: BACKGROUND: Knee injuries have been identified as the most common injury in rugby. Knee valgus has been identified as a risk factor for ligament injuries in athletes and predictors of knee valgus may assist in the design of knee injury prevention programs. PURPOSE: The purposes of this study were to use postural stability (PS) and strength measures to predict knee valgus angle during dynamic tasks, identify relationships between PS and strength, and compare measures …between positions. METHODS: Participants presenting positive during a gluteal dysfunction screening exam were enrolled. Participants performed PS, isokinetic strength, and biomechanical assessments. Stepwise multiple linear regression analyses were performed to identify predictors of knee valgus. Correlation coefficients identified relationships between PS and strength, and independent t-tests compared forwards and backs. RESULTS: Backs had significantly (p< 0.05) better PS and greater strength as compared to forwards. Hip abduction strength was correlated (r=− 0.52–−0.71, p< 0.05) with all eyes open static PS measures. Regression analysis failed to identify predictors of knee valgus angle. CONCLUSION: Although PS and strength were not multivariate predictors of knee valgus in male rugby players, bivariate correlations suggest that hip abduction strength training may be beneficial for enhancing PS. Show more

Keywords: Biomechanics, knee injuries, postural balance, muscle strength dynamometer, rugby union

DOI: 10.3233/IES-2012-0469

Citation: Isokinetics and Exercise Science, vol. 21, no. 1, pp. 37-46, 2013

Authors: Edouard, Pascal | Damotte, Alexandre | Lance, Gregory | Degache, Francis | Calmels, Paul

Article Type: Research Article

Abstract: BACKGROUND: Adaptations to Internal (IR) and external (ER) rotator shoulder muscles improving overhead throwing kinematics could lead to muscular strength imbalances and be considered an intrinsic risk factor for shoulder injury, as well as modified shoulder range of motion (RoM). OBJECTIVE: To establish profiles of internal and external rotation RoM and isokinetic IR and ER strength in adolescent- and national-level javelin throwers. METHODS: Fourteen healthy subjects were included in this preliminary cross-sectional study, 7 javelin throwers …(JTG) and 7 nonathletes (CG). Passive internal and external rotation RoM were measured at 90° of shoulder abduction. Isokinetic strength of dominant and non-dominant IR and ER was evaluated during concentric (60, 120 and 240°/s) and eccentric (60°/s) contractions by Con-Trex® dynamometer with the subject in a seated position with 45° of shoulder abduction in the scapular plane. RESULTS: We reported significantly lower internal rotation and significantly higher external rotation RoM in JTG than in CG. Concentric and eccentric IR and ER strength were significantly higher for the dominant shoulder side in JTG (P < 0.05), without significant differences in ER/IR ratios. CONCLUSIONS: The main finding of this preliminary study confirmed static and dynamic shoulder stabilizer adaptations due to javelin throw practice in a population of adolescent- and national-level javelin throwers. Show more

Keywords: Sports injury prevention, rotator cuff strength, isokinetic, range of motion, overhead sports, strength imbalance

DOI: 10.3233/IES-2012-0470

Citation: Isokinetics and Exercise Science, vol. 21, no. 1, pp. 47-55, 2013

Authors: Lewis Jr., Robert W. | Housh, Terry J. | Traylor, Daniel A. | Bergstrom, Haley C. | Schmidt, Richard J. | Johnson, Glen O. | Housh, Dona J.

Article Type: Research Article

Abstract: OBJECTIVE: This cross-sectional study examined the relationships between age and absolute peak torque (PT) as well as PT covaried for body weight (BW), height (HT), and/or fat-free weight (FFW) in young girl swimmers. METHODS: Twenty-nine girl swimmers (age=12.4 ± 1.9 yr) were measured for isokinetic elbow flexion and extension PT at 30, 180, 300° · s^{-1} , as well as BW, HT, and FFW. Zero-order correlations as well as first, second, and third-order partial …correlations were used to determine the relationships for age versus PT and age versus PT covaried for BW, HT, and/or FFW. RESULTS: There were age-related increases for all absolute PT measures (r=0.47 to 0.77), except elbow flexion at 300° · s^{-1} . For all but one of the measures (forearm extension at 30° · s^{-1} ; r=0.42 to 0.56), the increases in PT were accounted for by changes in BW, HT, and/or FFW. CONCLUSION: The results of this study indicated that agef-related increases in PT for four of the six measures were accounted for by BW, HT, and/or FFW. The age-related increases in PT for elbow flexion at 30° · s^{-1} independent of BW, HT, and/or FFW, may have been due to neuromuscular maturation. Show more

Keywords: Isokinetics, swimmers, age

DOI: 10.3233/IES-2012-0471

Citation: Isokinetics and Exercise Science, vol. 21, no. 1, pp. 57-61, 2013

Authors: Traylor, Daniel A. | Housh, Terry J. | Camic, Clayton L. | Zuniga, Jorge M. | Bergstrom, Haley C. | Johnson, Glen O. | Schmidt, Richard J. | Lewis, Jr., Robert W.

Article Type: Research Article

Abstract: OBJECTIVE: The purpose of the present study was to examine the effects of three sessions of concentric isokinetic training of the forearm flexors on peak torque (PT) at maximal voluntary isometric contraction (MVIC), 60, 180, and 300° · s^{-1} in males. METHODS: Ten adult males (mean age ± SD=21.8 ± 1.2 years; body mass=87.8 ± 18.4 kg; height=182 ± 9.5 cm) completed two pretests (pretest 1 and pretest 2) and a posttest that included maximal unilateral …isometric and concentric isokinetic forearm flexion (non-dominant arm) muscle actions at MVIC, 60, 180, and 300° · s^{-1} . During the three days of training, the subjects performed five sets of ten maximal isokinetic concentric forearm flexion (non-dominant arm) repetitions at 60° · s^{-1} . RESULTS: A three (pretest 1, pretest 2, and posttest) x four (MVIC, 60, 180, 300° ·s^{-1} ) repeated measures ANOVA indicated that there was no significant (p > 0.05) interaction, but significant main effects for time and velocity. The follow-up t-tests for marginal means indicated that the posttest (63.0 ± 13.1 Nm) was significantly greater than pretest 1 (55.8 ± 15.1 Nm) and pretest 2 (55.2 ± 12.4 Nm). CONCLUSION: Thus, the very short-term resistance training (VST) resulted in the same pattern of increase in PT at each velocity. In addition, PT decreased significantly with velocity. The current findings indicated that three days of concentric isokinetic training for the forearm flexors were sufficient to elicit increases in PT across a velocity spectrum (MVIC to 300° ·s^{-1}) . Show more

Keywords: Peak torque (PT), maximal voluntary isometric contraction (MVIC), very short-term resistance training (VST)

DOI: 10.3233/IES-2012-0472

Citation: Isokinetics and Exercise Science, vol. 21, no. 1, pp. 63-68, 2013

Authors: Ferraresi, Cleber | Baldissera, Vilmar | Perez, Sérgio E. A. | Júnior, Euclides M. | Bagnato, Vanderlei S. | Parizotto, Nivaldo A.

Article Type: Research Article

Abstract: The most typical maximum tests for measuring leg muscle performance are the one-repetition maximum leg press test (1RMleg) and the isokinetic knee extension/flexion (IKEF) test. Nevertheless, their inter-correlations have not been well documented, mainly the predicted values of these evaluations. This correlational and regression analysis study involved 30 healthy young males aged 18–24y, who have performed both tests. Pearson's product moment correlation between 1RMleg and IKEF varied from 0.20 to 0.69 and the more exact …predicted test was to 1RMleg (R^{2} =0.71). The study showed correlations between 1RMleg and IKEF although these tests are different (isotonic vs. isokinetic) and provided further support for cross determination of 1RMleg and IKEF by linear and multiple linear regression analysis. Show more

Keywords: One-repetition maximum test, isokinetic dynamometer, correlation, regression analysis

DOI: 10.3233/IES-2012-0473

Citation: Isokinetics and Exercise Science, vol. 21, no. 1, pp. 69-76, 2013

Authors: Tsuchiya, Yosuke | Ochi, Eisuke | Sakuraba, Keishoku | Kikuchi, Naoki | Hwang, Inkwan

Article Type: Research Article

Abstract: We investigated and compared isokinetic strength, anaerobic and intermittent capacity of men's lacrosse players at various playing positions. The subjects were 33 men's lacrosse players (attacker; ATn=11, defender; DFn=10, midfielder; MFn=12). Measurements contained physical characteristics, isokinetic strength, anaerobic capacity (maximal anaerobic power; Pmax, Wingate anaerobic power; WAnP), and 10-s (R10IC) and 20-s (R20IC) rest intervals of intermittent capacity. Knee flexor strength at angular velocities of 60°/s and 180°/s was …significantly greater in DF players than in AT players (p < 0.05), 300°/s was significantly higher in MF players than in AT players (p <0.05). With regard to Pmax, MF players showed significantly higher values compared with AT players (p < 0.05), and WAnP of MF players showed significantly higher values compared with that of AT and DF players (AT; p < 0.01, DF; p < 0.05). R10IC was significantly higher in MF players than in both AT and DF players (AT: p < 0.05, DF: p < 0.05), whereas R20IC was significantly higher in MF players than in AT players (p< 0.05). These results indicate that knee flexor strength, anaerobic capacity, and intermittent capacity are greater in μF than the other positions in men's lacrosse. Show more

Keywords: Lacrosse, positional characteristics, isokinetic strength, anaerobic capacity, intermittent capacity

DOI: 10.3233/IES-2012-0474

Citation: Isokinetics and Exercise Science, vol. 21, no. 1, pp. 77-82, 2013