Isokinetics and Exercise Science - Volume 10, issue 2

Authors: Tsaklis, P.

Article Type: Research Article

Abstract: This study focused on the design of an isokinetic test protocol for the evaluation of the anaerobic power-capacity of the knee extensors and flexors, and its validation using the Wingate 30'' anaerobic test. Twenty male track and field, sprint and jumping events athletes aged 17--28 years took part in the study. In the first session evaluation of lower limb anaerobic power took place. Following 48 hours their knee extensors and flexors were tested isokinetically (30 Reps …at 240°/sec for 30s). The results have indicated a very high correlation coefficient r=0.927 between the values of the medium power for both tests, while the correlation coefficient between the fatigue indexes was relatively low r=0.485. Thus isokinetic testing of knee musculature could provide a valid measure of the anaerobic capacity of the knee extensors and flexors, particularly with respect to athletes who perform through the anaerobic glycolitic way. On the other hand, isokinetically-based fatigue could not be compared with the more common and is therefore not advisable as an alternative indicator to the Wingate test. Show more

Keywords: anaerobic power-capacity, Wingate test, knee muscles

DOI: 10.3233/IES-2002-0085

Citation: Isokinetics and Exercise Science, vol. 10, no. 2, pp. 69-72, 2002

Authors: Beneka, A. | Malliou, P. | Giannakopoulos, K. | Kyrialanis, P. | Godolias, G.

Article Type: Research Article

Abstract: Thirty six Physical Education students participated in this study and were randomly assigned in three groups: a. The first experimental `isokinetic group' (N=12) followed an isokinetic strengthening program for the rotator cuff muscle group. Its isokinetic exercise protocol consisted of 10 set of 10 repetitions at 90, 120, 180, 210, 240, 240, 210, 180, 120 and 90~deg/sec respectively, b. The second experimental `MJDR group' (N=12) used the multi joint dynamic resistance training mode for the same …muscle group. Its exercise program consisted of four exercises: 1. Pull-ups or lat pull downs, 2. Overhead press, 3. Reverse pull ups and 4. Push-ups (submaximal effort, 8--15 repetitions in 3--7 sets, rest between sets ranging from 2--4 minutes), c. The `control' group (N=12) had no strengthening training. Testing was performed in the supine position with the glenohumeral joint in 900 of abduction in the coronal plane, with a range of motion of 0--900 of external rotation and 0--650 of internal rotation at 60, 120 and at 1800/sec. The testing procedure was performed before and after the exercise period of six weeks. The results showed that in both movements and extremities the performance improvement was not the same for the three groups (interaction 'group' and 'test'). In both internal and external rotation and both extremities, statistically significant improvement in performance was observed only for the two experimental groups. Show more

Keywords: isokinetic exercise, isotonic exercise, dynamic resistance training mode, rotator cuff

DOI: 10.3233/IES-2002-0087

Citation: Isokinetics and Exercise Science, vol. 10, no. 2, pp. 73-79, 2002

Authors: Andrade, M.S. | Cohen, M. | Piçarro, I.C. | Silva, A.C.

Article Type: Research Article

Abstract: The aim of this study was to determine differences in isokinetic performance, hop tests, range of motion and thigh circumference between the involved and uninvolved leg in patients after 4, 5, 6 and 8 months after anterior cruciate ligament (ACL) reconstruction and to investigate the possible correlation between the different evaluation methods. Fourteen male subjects submitted to intra-articular reconstruction of the anterior cruciate ligament with patellar tendon graft. All parameters improved from the 4th to the …8th month post-op. The deficits were more pronounced for the quadriceps than for the hamstrings, which regained full function at 5 months. Quadriceps performance and thigh circumference were impaired even after 8 months. According to the Lysholm Score, all subjects scored at least as good function and 54% correlation between quadriceps performance and both single and triple hops (0.51--0.63), whilst for the harmstrings the correlations were weak (0.32--0.44). We conclude that: 1) Individuals with anterior cruciate ligament injury present quadriceps weakness even after 8 months of the reconstructive surgery using patellar tendon graft; 2) when an isokinetic dynamometer is not available, horizontal impulse tests can be used to evaluate quadriceps deficiency; 3) thigh circumference should not be used as a measurement to predict muscle performance; 4) the Lysholm Score is not sensitive to detect limitations in muscle performance. Show more

DOI: 10.3233/IES-2002-0088

Citation: Isokinetics and Exercise Science, vol. 10, no. 2, pp. 81-86, 2002

Authors: Liebermann, Dario G. | Maitland, Murray E. | Katz, Larry

Article Type: Research Article

Abstract: {\it Purpose:} This study was aimed to explore the relationship between lower limb extension power measured by isokinetic knee extensions (IK) and vertical jumps performed on a force plate (VJ) and speed skating (SS) sprint power measured by a laser device. {\it Methods:} Twenty elite short- and long-track speed skaters performed 100 m sprints followed by VJ and IK trials. Power-time curves were calculated off-line. Pearson correlation coefficients were used to determine the degree of …association between the variables. {\it Results:} SS sprint power correlates strongly with VJ power (r=0.870; p<0.001) while IK power showed a weaker but significant correlation to both (r=0.707 and r=0.706, respectively; p<0.01). As expected, SS times at 15 m and 100 m were inversely associated with SS sprint power (r=-0.818 and r=-0.909; p<0.001) and VJ power (r=-0.730 and r=-0.763; p<0.001), and to a lesser degree with IK power (r=-0.602; r=-0.618; p<0.01). {\it Conclusion:} The analyses differentiate between methods of estimating power in speed skaters, and show a strong relationship between initial SS performance and muscular power. Given that 100 m split times strongly relate to final 500 m results (r=0.972; p<0.001, N=332), it is reasonable to believe that an initial power and a stable peak speed before the first curve may lead to achieving the winning edge in short SS events. A finding of particular interest is that isokinetic power results are correlated significantly with the practical outcomes of the performance in spite of the high specificity of the isokinetic testing method. Show more

DOI: 10.3233/IES-2002-0089

Citation: Isokinetics and Exercise Science, vol. 10, no. 2, pp. 87-95, 2002

Authors: Kellis, Eleftherios

Article Type: Research Article

Abstract: One of the most important assumptions of the passive method of gravity correction in isokinetic dynamometry is that subjects are relaxed during the test. The purpose of this study was to examine the validity of the passive gravity correction method in pubertal children. Fifteen pubertal males performed passive knee extensions and flexions at 30°·s^{-1} . The electromyographic (EMG) activity of the vastus medialis (VM), vastus lateralis (VL) and biceps femoris (BF) was …recorded using bipolar surface electrodes. The GM was estimated using five different methods: the recorded GM during knee extension and flexion, the estimated GMs from the recorded knee extension and flexion GMs at 30° of knee flexion and the GM estimated using anthropometric data. The results indicated that the passive knee movements resulted in significantly (p<0.05) higher GM compared to those estimated using anthropometric data or mathematically using the GM at 30°. The GM in the range of 31--90° was significantly (p<0.05) higher during knee extension compared with knee flexion. The VM and VL raw EMGs were significantly (p<0.05) higher during knee extension compared to knee flexion movement, reaching 40% of the their maximum EMG values. The BF EMG ranged from 7% to 10% of the maximum, but it was not significantly different between extension and flexion phases. It can be suggested that the recorded dynamometer moment during passive gravity correction tests is affected by forces exerted by musculotendinous structures which are activated during the test. The application of passive gravity correction techniques in pubertal children demonstrates significant problems and should be applied with extreme caution. Show more

Keywords: gravitational, isokinetics, knee, strength, isokinetic dynamometry

DOI: 10.3233/IES-2002-0090

Citation: Isokinetics and Exercise Science, vol. 10, no. 2, pp. 97-105, 2002

Authors: Tsiokanos, Athanasios | Kellis, Eleftherios | Jamurtas, Athanasios | Kellis, Spiros

Article Type: Research Article

Abstract: The purpose of this study was to examine the relationship between vertical jumping performance and isokinetic moment of force of knee extensors, hip extensors and ankle plantar flexors in adult males. Twenty-nine males performed squat and counter movement jumps on an Egrojump device. The peak jumping height and the total work (height × body mass) were used as indicators of vertical jump performance. The subjects also performed three submaximal and three maximal isokinetic efforts of the …hip extensors, knee extensors and ankle plantarflexors at angular velocities of 60, 120 and 180 °·s^{-1} on Cybex Norm Dynamometer. Pearson's product correlation tests indicated that there was a significant (p<0.05) positive relationship between vertical jumping height and total work with hip and knee extension moments, whereas low correlation coefficients between isokinetic moment of the ankle plantarflexors and jumping performance were found p<0.05). Multiple regression analysis indicated that linear combinations of isokinetic torques accounted for 38% countermovement and squat jumping height variance, respectively. In contrast, regression models using isokinetic torques could predict jumping work accounting for 75% (squat jump) of the variance. The above results indicate that there is a moderate to high relationship between isokinetic knee and hip extension torques and vertical jump performance parameters, especially when jumping height is multiplied by subject's body weight. Furthermore, it appears that when using a linear combination of isokinetic torques from hip and knee joint muscle groups the multiple relationship between isokinetic tests and jumping performance is higher. Show more

Keywords: vertical jump, isokinetic, knee, ankle, hip, prediction

DOI: 10.3233/IES-2002-0092

Citation: Isokinetics and Exercise Science, vol. 10, no. 2, pp. 107-115, 2002

Authors: Weissland, T. | Voisin, P. | Tomaszewski, A. | Delahaye, H. | Vanvelcenaher, J.

Article Type: Abstract

Abstract: This Abstract was presented at the Second European Isokinetic Society Congress, Neuromuscular Performance in Research and Clinical Applications, March 15 and 16, 2002, Crans Montana, Switzerland.

DOI: 10.3233/IES-2002-0086

Citation: Isokinetics and Exercise Science, vol. 10, no. 2, pp. 117-118, 2002