Isokinetics and Exercise Science - Volume 20, issue 3

Authors: Dirnberger, Johannes | Wiesinger, Hans-Peter | Kösters, Alexander | Müller, Erich

Article Type: Research Article

Abstract: The present study was conducted to evaluate the relative and absolute reproducibility of the IsoMed 2000-dynamometer in measuring Peak Torque (PT) during maximum isometric and isokinetic (60 and 120°/s) knee flexion and extension. Thirty four physically active male subjects (mean age: 23.2 years) were measured in three sessions (T1–T3), 48–72 h apart. Repeated measures analysis of variance (ANOVA) with Bonferroni post hoc adjustments revealed significant systematic errors for isokinetic flexion measurements with …mean values on the second and third visit being around 3–5% than the corresponding values obtained in the first visit. Intraclass correlation coefficients (ICC 2,1) of 0.90–0.98 and 0.94–0.98 combined with values of standard error of measurement (SEM) of 5.5–9.1 and 4.0–9.0 Nm were found for T1–T2 and T2–T3, respectively. Based on the systematic errors found for flexor measurements and a clear improvement in reproducibility parameters from T1–T2 to T2–T3 for nearly all measurements, we recommend the use of a familiarisation session prior to actual testing. Show more

Keywords: Reproducibility, isometric and isokinetic maximum strength testing, knee flexion and extension, IsoMed 2000-dynamometer

DOI: 10.3233/IES-2012-0451

Citation: Isokinetics and Exercise Science, vol. 20, no. 3, pp. 149-153, 2012

Authors: Croce, R.V. | Miller, J.P. | Smith, W.J. | Horvat, M.

Article Type: Research Article

Abstract: The effect of contraction intensity (100%-, 75%-, 50%-, and 25%-maximum voluntary contraction [MVC]) and movement velocity (0°, 100°, 200°, 300°, and 400°/s) on the root mean square amplitude (SEMG-RMS) and median frequency power spectrum (SEMG-MPF) of the surface electromyography of the vastus medialis (VM) and rectus femoris (RF) muscles during isokinetic extension movements was investigated. Eight healthy female university students (age=23.1 ± 2.6 yrs., mean height=161.8 ± 6.8 cm, mean weight=64.6 ± …6.1 kg) with no known knee pathologies participated in the study. Peak moment (PM), SEMG-MPF, and SEMG-RMS were analyzed using separate repeated measures analysis of variance (ANOVA). Results indicated (p⩽ 0.05): (1) an inverse relationship between PM and movement velocity, which was consistent with the literature and the force-velocity curve; (2) an increase in VM and RF SEMG-RMS across all isovelocity movements compared to isometric, with highest values occurring at 200°/s; (2) a linear increase in SEMG-RMS as force levels increased from 25%-MVC to 100%-MVC; and, (3) an increase in SEMG-MPF values during isovelocity movements compared to that found during isometric contractions, with highest values at 50°/s, suggesting isovelocity movements facilitated a greater recruitment of fast-twitch fibers. It appears that the degree to which the central nervous system activates muscle is based on the interplay of both contraction intensity and velocity needed to complete the required motor task. Show more

Keywords: Isokinetic knee extension, quadriceps muscle, surface EMG, EMG power spectra

DOI: 10.3233/IES-2012-0452

Citation: Isokinetics and Exercise Science, vol. 20, no. 3, pp. 155-165, 2012

Authors: Yalcin, Elif | Kurtaran, Aydan | Selcuk, Barin | Onder, Burcu | Yildirim, Makbule Ozge | Akyuz, Mufit

Article Type: Research Article

Abstract: Background: Flexible flatfoot deformity is likely to be caused by ligamentous laxity of the medial longitudinal arch, and this deformity could change the mechanics of other joints, ligaments and tendons as well as foot alignment. Aim: We hypothesized that position sense and muscle strength could be impaired in patients with flatfoot compared to normal controls, therefore we investigated position sense and ankle eversion inversion strengths of individuals with flexible flatfoot. Design: Cross …sectional study. Setting: A rehabilitation center. Population: Twenty-six individuals with flexible flatfoot and 27 healthy control subjects were evaluated. Methods: Absolute error (in degrees) for passive reproduction of joint position tests and peak isokinetic strength of ankle muscles for eversion and inversion were tested using the Biodex isokinetic dynamometer. Results: For individuals with flatfoot, passive reproduction of joint position error scores in eversion were significantly higher for the dominant side compared with the control group. No significant differences in eversion and inversion muscle strength between flexible flatfoot and control groups were found. Conclusion: We suggest that flexible flatfoot deformity may cause deficits in proprioception accuracy. Clinical Rehabilitation Impact: In our opinion, clinicians must be aware and should take into account this possible deficit in the management of these patients. Show more

Keywords: Proprioception, flexible flatfoot, isokinetic, ankle joint

DOI: 10.3233/IES-2012-0453

Citation: Isokinetics and Exercise Science, vol. 20, no. 3, pp. 167-171, 2012

Authors: Steinfeld, Yael | Shabat, Shay | Nyska, Meir | Peretz, Chava | Dvir, Zeevi

Article Type: Research Article

Abstract: Background: Outcome measures of operative intervention for ankle fractures indicate poor subjective and objective results. Though patients regain full range of motion they often complain of pain and fatigability. Specifically, there is a paucity of data regarding strength characteristics of the relevant muscles after surgical intervention. Objective: Describe the strength characteristics of ankle invertors (INs) and evertors (EVs) and explore their relationship to the ankle-hindfoot scale (AHS) in patients after surgical intervention for ankle …fractures. Method: Bilateral isokinetic concentric and eccentric INs and EVs strength was measured in 24 patients, 6–12 months following surgery. Additional subjective and objective factors were evaluated using the AHS. Results: Strength of the involved limb muscles was significantly lower compared to the contra-lateral muscles (p<0.0001). However, strength reduction was significantly greater in the INs (27.6–37.5%) than the EVs (14.4–24.3%), (p=0.0005). The EVs/INs ratio of the uninvolved limb (89–102%) was significantly lower than the ratio of the involved limb (111–141%), (p<0.0001). The clinical status of the limb was found to have a significant effect on all dynamic control ratios (DCRs): EVR(E)/INV(C), INV(E)/EVR(C), EVR(C)/INV(E), and INV(C)/EVR(E) (P<0.0001, P=0.0032, P=0.0001, and P=0.0015, respectively). A significant relationship was found between the mean AHS score and relative unilateral weakness (r=−0.58, p=0.003). Conclusions: Strength reduction could be one of the reasons for the functional decline following ankle fractures. The weakness of the INs muscles of the ankle is more pronounced than that of the EVs. Show more

Keywords: Ankle fractures, muscle strength, dynamic control ratios, invertors, evertors

DOI: 10.3233/IES-2012-0454

Citation: Isokinetics and Exercise Science, vol. 20, no. 3, pp. 173-179, 2012

Authors: Cerrah, Ali Onur | Güngör, Elvin Onarıcı | Yılmaz, İlker

Article Type: Research Article

Abstract: The aim of the current study was to determine ball velocity and throwing distance in standing and running throw-in techniques, and to correlate this performances with isokinetic torques of the, elbow, shoulder, and trunk extensors and flexors. 14 male amateur soccer players volunteered to participate to the current study. Concentric Isokinetic tests were measured at 60 and 180°/s angular velocities for elbow and shoulder, 30 and 120°/s angular velocities for trunk. Ball …velocity was measured by a radar gun and the throwing distance was measured regarding throw-in performance. Unpaired t-test was used to analyze ball velocity and throwing distance differences between two different throwing techniques. To clarify relationship between isokinetic strength values and ball velocities and distance which occur during two types of throwing techniques Pearson Correlation Analyze was used. There were no statistical significant differences regarding throwing velocity and distance between two different throw-in techniques. Even though, the isokinetic values and throwing velocities did not correlate with each other, there was a positive correlation between standing throw-in distance with elbow (non–dominant flexion at 60 and 180°s^{-1} ), shoulder (dominant flexion-extension at 60 and 180°s^{-1} , non-dominant extension at 60 and 180°s^{ - 1} ) and trunk (flexion at 30 and 120°s^{ - 1} ). The only correlation between running throw-in and throwing distance occurred in shoulder (dominant extension at 60°s^{ - 1} ) and trunk (flexion at 30°s^{ - 1} ). In conclusion, the isokinetic strength values regarding upper extremity is strong factor that describes standing throw-in performance. However; it is not highly correlated with the running throw-in performance in soccer. Show more

Keywords: Soccer, throw-in, isokinetic, peak torque

DOI: 10.3233/IES-2012-0457

Citation: Isokinetics and Exercise Science, vol. 20, no. 3, pp. 181-187, 2012

Authors: Kaya, Defne | Callaghan, Michael J. | Donmez, Gurhan | Doral, Mahmut Nedim

Article Type: Research Article

Abstract: Purpose: The aim of this study was to assess the relationship between the free-throw percentage, joint position sense, and muscle torque in professional basketball players. Methods: Eleven professional basketball players participated in the study, with each subject acting as their own internal control by using the non-dominant side. Knee and shoulder joint of the players were evaluated bilaterally. Flexion and extension peak torque of the knee were evaluated isokinetically system. In addition …flexion/abduction/external rotation (F/ABD/ER) and extension/adduction/ internal rotation (E/ADD/IR) diagonal pattern peak torque of the shoulder were measured. The joint position sense of both knees and shoulders were evaluated using an active angle reproduction. Thirty, 45, 60 and 75° target angles were used for knee and 160, 135, and 120° target angles were used shoulder. The free-throw percentage of the players for 40~matches in the 2009–2010 season was taken from the Turkish Basketball League official website. The relationship between the peak torque of the muscles, joint position sense, and the free-throw percentage was evaluated. Results: There were no significant differences in the peak torques of the knee and shoulder muscles and joint position sense between the dominant and non-dominant sides (p> 0.05). There was a significant correlation between the free-throw percentage and the peak torque of the shoulder muscles during the F/ABD/ER pattern at 60°/s in the dominant side of the players. There was a borderline trend to significance between the free-throw percentage and the shoulder joint position sense (eyes-closed and at 160°) in the dominant side. There was a borderline significant correlation between the free-throw percentage and the knee joint position sense (eyes-open and at 75°) in the dominant side. Conclusions: The effect of proprioceptive and strengthening exercises on the free-throw percentage is still unknown. Further comprehensive studies are warranted to analyze the effect of proprioceptive and strengthening exercises on the free-throw percentage in elite basketball players. Show more

Keywords: Free-throw, peak torque, joint position sense, knee, shoulder, basketball

DOI: 10.3233/IES-2012-0458

Citation: Isokinetics and Exercise Science, vol. 20, no. 3, pp. 189-196, 2012

Authors: Podstawski, Robert | Choszcz, Dariusz | Siemianowska, Ewa | Skibniewska, Krystyna A.

Article Type: Research Article

Abstract: The aim of the study was to determine the effect of selected individual factors (independent variables) on the dependent variable of a simulated rowing distance in a group of physically inactive females. The independent variables were the women's age, body mass (kg) and height (cm), and the BMI index. The time required to cover the simulated distance of 1000 m was adopted as the dependent variable. The study involved 258 female students who participated only in …the obligatory physical education classes. Research revealed that the relationships between anthropometric parameters and the time required to complete 1000 m on a rowing ergometer differ among physically inactive women and elite rowers. In both physically inactive women as well as elite rowers an increase in body height had a positive influence on the time (shorter time). In the case of body mass, its increase in our study subjects resulted in poorer times, which is contrary to the results of studies conducted on elite rowers. This is most likely due to the fact that the body mass of athletes consists mainly of lean body mass, whereas physically inactive females are characterized by a higher percentage of body fat. Moreover, the time taken to complete the rowing trial was shortest for students with BMI values ranging from 17 to 21. The conducted research led to the conclusion that the analyzed anthropometric parameters affect the time needed by women to cover a distance of 1000 m on a rowing ergometer. Further studies should be conducted to include additional anthropometric and physiological parameters. Show more

Keywords: Motor fitness, somatic traits, young women, rowing ergometer

DOI: 10.3233/IES-2012-0459

Citation: Isokinetics and Exercise Science, vol. 20, no. 3, pp. 197-204, 2012

Authors: Güney, Şevin | İlhan, Ayşe Şebnem | Çetin, Ferihan | Dinçer, Sibel

Article Type: Research Article

Abstract: Physical exercise increases the level of endogenous opiates that possibly play a major role for integration of hormonal and metabolic responses to exercise. Increased endogenous opioids in response to physical activity may enhance the performance through decreasing pain perception. However, what possible effect the opioid peptides have on physical exercise at the level of central nervous system remains to be elucidated. In this study, naloxone (N=6), and naltrindole (N=8) were administered intracerebroventrically to rats. A …physiologic saline group (N=10) and a control group (N=8) were also included in the study. All groups were then subjected to exhaustive exercise on a treadmill. Besides recording the exhaustion time, blood glucose and lactate levels were measured before and after exercise. Treatments with naloxone and naltrindole had no effect on the exhaustion time. In comparison with pre-exercise period, lactate levels increased, while glucose levels decreased significantly in the blood of all animals during post-exercise period. However, decreased level of glucose in the post-exercise period was statistically significant only in those treated with naltrindole, compared with the other groups. Our findings indicate that the central endogenous opioid peptides may have a role in the regulation of glucose metabolism during exhaustive exercise. This effect can be mediated via delta opioid receptors, although they exert no effect on the performance, namely, on the exhaustion time. Show more

Keywords: Exercise, endogenous opioid, delta opioid receptor, rat, naltrindole, blood glucose level

DOI: 10.3233/IES-2012-0460

Citation: Isokinetics and Exercise Science, vol. 20, no. 3, pp. 205-209, 2012

Authors: Lockie, Robert G. | Schultz, Adrian B. | Jeffriess, Matthew D. | Callaghan, Samuel J.

Article Type: Research Article

Abstract: This study analyzed relationships between bilateral concentric (60°/s, 180°/s, 240°/s) and eccentric (30°/s) knee extensor and flexor strength differences, and linear (40-meter sprint), and change-of-direction (T-test) speed in 16 male team sport athletes. It was hypothesized that lower between-leg strength differences would be associated with faster speeds. Subjects were divided into faster and slower groups based on total time; a one-way analysis of variance (p ⩽ 0.05) determined bilateral torque and work …differences that distinguished the groups. All data was combined to correlate (p⩽ 0.05) torque and work differences with sprint times. The faster group exhibited greater differences in concentric knee extensor torque at 240°/s (faster=11.74 ± 8.65%; slower= 4.13 ± 4.34%), and smaller differences in eccentric knee flexor torque (faster=5.64 ± 4.10%; slower=12.41 ± 7.55%) and work (faster=6.36 ± 6.65%; slower=15.55 ± 6.05%). Negative correlations were found between concentric 180°/s and 240°/s knee extensor torque differences and sprint times; however, speed was not negatively affected. Positive correlations existed between eccentric knee flexor work differences and sprint times. Eccentric strength differences negatively impacted multi-directional speed, as balanced eccentric strength is necessary for effective sprinting, deceleration, and changing direction. Show more

Keywords: Linear speed, change-of-direction speed, side-to-side deficit, eccentric strength, lower-limb imbalance

DOI: 10.3233/IES-2012-0461

Citation: Isokinetics and Exercise Science, vol. 20, no. 3, pp. 211-219, 2012

Authors: Rebai, Haithem | Zarrouk, Nidhal | Ghroubi, Sameh | Sellami, Mouna | Ayedi, Fatma | Baklouti, Sofien | Elleuch, Mohamed Habib | Elleuch, Mohamed

Article Type: Research Article

Abstract: Aim: To evaluate bone mass in female basketball players and the relationship between bone mineral density (BMD) and isokinetic muscle strength. Methods: We investigated 29 female basketball players, age 21.9 ± 9.1 years, training for about 6–8 hours per week. The reference group consisted of 22 non-active female, age 21.4 – 1.5 years. BMD was measured using dual-energy-X-ray absorptiometry in total body, lumbar spine, the whole femur and humerus. Isokinetic peak torque of the quadriceps and hamstring …muscles were measured at 60 and 180°/s. Osteocalcin (OC) and cross-linked C-telopeptide (CTX) were measured by radioimmunoassay and electrochimiluminescence, respectively. Results: Compared to the controls, the basketball group had significantly (P <0.001) a higher BMD in the total body (11.6%), the lumbar spine (9.83%), the dominant femur (16.8%), the non-dominant femur (15.8%) and the dominant humerus (8.47%). The female basketball players had also significantly higher peak torques at both isokinetic velocities (60 and 180°/s) and for both lower limbs. All muscle peak torque measured for the female basketball players were significantly correlated with correspondent leg BMD and for both velocities tested. However, no significant correlations were noted for the control group. Values of formation (OC) and resorption (CTX) markers were significantly higher in the athletic females (P < 0.01 and P < 0.05, respectively). Conclusion: Our results show clearly that practice of basketball is associated with the improvement of bone mass. In addition, the most important finding of our study is that isokinetic muscle strength seems to be correlated with correspondent BMD in female basketball players. Show more

Keywords: Bone mass, sports activities, female, muscle, isokinetic

DOI: 10.3233/IES-2012-0463

Citation: Isokinetics and Exercise Science, vol. 20, no. 3, pp. 221-227, 2012