Isokinetics and Exercise Science - Volume 5, issue 2
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Isokinetics and Exercise Science (IES) is an international journal devoted to the study of theoretical and applied aspects of human muscle performance. Since isokinetic dynamometry constitutes the major tool in this area, the journal takes a particular interest in exploring the considerable potential of this technology.
Isokinetics and Exercise Science publishes studies associated with the methodology of muscle performance especially with respect to the issues of reproducibility and validity of testing, description of normal and pathological mechanical parameters which are derivable from muscle testing, applications in basic research topics such as motor learning paradigms and electromyography. The journal also publishes studies on applications in clinical settings and technical aspects of the various measurement systems employed in human muscle performance research.
Isokinetics and Exercise Science welcomes submissions in the form of research papers, reviews, case studies and technical reports from professionals in the fields of sports medicine, orthopaedic and neurological rehabilitation and exercise physiology.
Abstract: Anterior knee pain syndromes are among the most common sources of pain and dysfunction at the knee. Numerous attempts have been made to identify exercises that selectively promote action of the vastus medialis oblique (VMO) muscle in order to counter lateral patellar tracking. The purpose of this study was to evaluate (via EMG) action of the VMO muscle versus the vastus lateralis (VL) muscle during two exercises. First, EMG ratios were evaluated during isolated knee extension and then repeated with isometric hip adduction during knee extension. The results of this study demonstrated a statistically-significant decrease in VL activity during knee…extension combined with isometric hip adduction. Inhibition of the vastus lateralis allows more favorable medialization of the patella by the VMO, potentially making knee extension with isometric hip adduction an effective adjunct to patellofemoral rehabilitation.
Abstract: The effects of intensive training on young national competition gymnasts have not been established with precision. This study analyzed, using an isokinetic dynamometer at speeds 60°/s and 120°/s, the concentric and eccentric isokinetic muscle strength of knee flexors and extensors in a population of nine young national caliber gymnasts. Results: eccentric strength is greater than concentric strength, there's no significant difference between dominant and non-dominant limb, and a significant increase of the flexor/extensor peak torque ratio was observed with increasing speed, due to the concentric ratios. These results provide information about the relationship between angular velocity and eccentric muscle…strength already reported in previous studies and, in particular, the fact that the knee flexors and extensors behave differently during eccentric and concentric work as the angular velocity increases. Analysis of the flexor/extensor ratio also indicated the absence of specific differentiation of muscle activity despite the intensive level of sports activity and suggests the role of age, or even puberty, in these young gymnasts. This analysis encourages annual follow-up of this population and specific studies concerning the role of hormones and muscle maturation.
Abstract: With the increasing use of isokinetic devices, a need exists to establish the inter and intra machine reliability of devices reputedly measuring the same outcome measure. The maximum peak torque values generated while 15 subjects performed internal and external shoulder rotation at the velocities of 60, 120 and 160°/s were recorded on three separate isokinetic machines: Kin-Com, Cybex II, and Lido. Statistical analyses in the form of analysis of variance and intraclass correlation coefficients were performed. The ANOY A revealed significant differences (P> 0.001), across subjects as planned, but also across machines apart from when measuring internal shoulder rotation at…60°/s (P > 0.001). ICCs were all high and significant (P > 0.001), but at anyone time apart from the recording at 60°/s for internal rotation, only two of the three machines were in agreement. For internal rotation, the Kin-Com gave consistently lower values than the other two machines, while for external rotation the Lido gave consistently lower values.
Abstract: Using the Kin-Com (Chattecx Corp, Hixson, TN) isokinetic dynamometer, 20 university females (age = 21.6 ± 1.4 years, wt = 61.73 ± 7.3 kg, ht = 162.81 ± 5.8 cm) performed concentric and eccentric isokinetic contractions at nine different velocities. At each velocity, subjects performed two submaximal and one maximal concentric and eccentric familiarization contractions. Three alternating concentric and eccentric maximal contractions followed a 1-min rest between the familiarization and maximal contractions. One minute of rest was also provided between the test contractions and the next set of familiarization contractions. The peak torque (PT) and average torque (AT) for the…first and ninth set of contractions were analyzed with separate repeated measures ANOV As. The results demonstrated no significant differences for the interaction or for the test main effect for either PT or AT. This suggests that with appropriate rest intervals, as many as 96 submaximal and maximal concentric and eccentric contractions can be performed without fatigue affecting assessment of PT and AT.
Keywords: Rest intervals, Fatigue, Isokinetic assessment at multiple speeds
Abstract: The purpose of this study was to determine the reliability of the Kinetic Communicator's (Kin-Com) gravity correction procedure. To determine mechanical reliability, gravity correction was performed at 11 different angles while weights (1.15, 2.30, 3.45 and 4.60 kg) were suspended from the lever arm. Intrac1ass correlation (ICC) between trials showed that the Kin-Com was able to gravity correct weights with high reliability (R = 0.961–0.999). Gravity correction values from the 11 angles were analyzed with a one-way analysis of variance with repeated measures to determine if differences existed between gravity correction values collected at different angles for each weight condition.…Even though reliability was good for each angle, gravity correction values collected near the vertical position differed from the gravity correction values collected at the horizontal position (P < 05). Differences decreased as weight increased. To determine clinical reliability, 25 subjects (age = 21.0 years, height = 16.6 cm, weight = 59.8 kg) were also gravity corrected in both the seated and prone positions at six different angles on 2 separate days. Correlation analysis between days showed good reliability (R = 0.83) for both positions when subjects were corrected at the horizontal. Reliability decreased as the lever arm approached vertical. Differences between gravity correction values existed at every angle measured for both positions. Even though the gravity correction was shown to be reliable at positions other than the horizontal, gravity correction should be performed at the horizontal position each time subjects are assessed.
Keywords: Gravity correction, Reliability via positions
Abstract: The purpose of this study was to compare the use of average moment (AVM) vs. peak moment (PM) in analyzing muscle strength. Two groups of healthy subjects in whom the strength of the knee extensor (group Q, N = 16) and trunk extensors (group T, N = 20) was assessed, took part in the study. Using four intermittent concentric-eccentric contractions at two angular velocities, subjects were asked to exert three distinct strength levels: one maximal and two submaximal. The main findings point out that in spite of the high correlations between the two strength parameters, generally in excess of 0.9,…the relationship between the AVM and the PM behaved differently in the knee extensors compared with the trunk extensors. Moreover, with respect to the knee extensors this relationship differed among the levels of exertion. In the light of the discussion, it is suggested that ratios based on inter-muscle (bilateral) or intra-muscle (eg concentric vs. eccentric ratios) performance would probably be better represented by the AVM.
Keywords: Average moment (torque), Peak moment (torque)
Abstract: The functional efficacy of arthroscopic excision of the plica in 33 patients (27 men, six women) was assessed based on quadriceps performance and pain relief, prior to and following intervention. The concentric (C) and eccentric (E) strength of the quadriceps was measured isokinetically at low and medium velocities (30 and 120°/s) while the pain level during these efforts was recorded using the Borg modified (0–10) pain scale. Following the intervention, there was on average 16% improvement in the strength of the quadriceps of the involved side versus 5% in the uninvolved side. The effort induced pain was reduced on average…4.76 and 4.21 points during C and E contractions, respectively, which amounted to an almost absolute pain relief. In view of these findings, it is suggested that preoperative qualitative assessment of the pain during isokinetic testing together with assessment of quadriceps functional performance may be effectively and routinely integrated within the general framework of knee examination, in suspected plica pathology. The improvement of pain and quadriceps function during postoperative isokinetic reassessment confirm the hypothesis that the suprapatellar and the mediopatellar plicae are potent causes of anterior knee pain.