Isokinetics and Exercise Science - Volume 1, issue 3
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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: The purpose of this study was to determine upper extremity strength values. Thirty healthy, nonathletic males participated. Bilateral upper extremity isokinetic testing of shoulder, elbow, and wrist occurred at speeds of 60, 180, and 300 deg/sec. Total arm strength (TAS), total arm work (TAW), and total arm average power (TAAP) were calculated for each extremity. A paired t-test was used to compare TAS, TAW, and TAAP values between the dominant and nondominant upper extremities. Statistically significant differences between upper extremities were observed at all three speeds for TAS, TAW, and TAAP. The relationship between body weight and each of the…variables of TAS, TAW, and TAAP was statistically significant for TAS and TAW at all three speeds, while TAAP demonstrated a correlation only at 180 deg/sec. Further research is needed in the area of total arm strength.
Keywords: Total arm strength (TAS), total arm work (TAW), total arm average power (TAAP), upper extremity isokinetic evaluation
Abstract: Normative data are needed to permit physical therapists to determine if patient measurements of strength are within normal limits. However, to generate normative data, it is essential to evaluate large numbers of subjects. This is only possible with collaboration to pool measurements across different sites with different examiners. This study evaluated the consistency of repeated isokinetic knee flexion and extension measurements with the same subjects tested on the Cybex 340 Extremity Unit with two different examiners at two different sites following the same protocol and then different protocols. The t test was used to determine if the mean difference scores…significantly varied from zero (p = .05). Within the same site, following the same protocol, there were no significant differences in measurement by the two examiners for peak torque (at 90, 120, or 180 deg/sec), work in flexion (120 deg/sec) or endurance (120 deg/sec), but there was a significant difference in work extension. By site, there were no significant differences in repeated measurements for peak torque, work, or endurance (120 deg/sec). There were significant differences in peak torque flexion when different protocols were used, even when the same examiner was testing at the same site. The coefficients of variation for the repeated measurements varied from 4.5% to 13.6%. The results from this study suggest that physical therapists from different sites could collaborate to pool data for developing norms for isokinetic knee flexion and extension torque as long as the same test protocol was followed. However, the large variation in retest measurements and the coefficient of variation suggest that when a therapist wants to determine if a patient has made a significant gain in strength, the remeasurement should be taken by the same examiner at the same site. More research is needed to determine if the consistency of isokinetic torque testing with different examiners and different sites is equally high for other muscle groups and with other types of isokinetic dynamometers.
Abstract: The purpose of this study was to examine normative data for uninjured adults when tested isokinetically over a velocity spectrum. Sixty adults, 30 males and 30 females, between the ages of 20 and 62, were tested for quadriceps femoris and hamstring peak torque, quadriceps femoris peak torque/body weight ratio, quadriceps femoris average work, quadriceps femoris average power, and quadriceps femoris angle of peak torque. Subjects were tested at 60, 180, 300, 400, and 500 deg/sec. Mean isokinetic values versus speed were determined for both males and females to allow visual analysis of the change in these parameters over the velocity…spectrum. Personal data, including reported weekly exercise regimen, were assessed using Pearson correlation coefficients to analyze any association among demographic factors and isokinetically produced values at 180 deg/sec. Finally, a regression analysis was used to formulate an equation to predict peak torque, average work, and average power for the right quadriceps femoris at 180 deg/sec.
Keywords: Velocity spectrum, quadriceps femoris/hamstring, average work/average power
Abstract: The purpose of this study was to compare the overall peak torque per kilogram body weight (peak torque/kg) and hamstring to quadriceps femoris (H/Q) peak torque ratios between 13 male intercollegiate sprint athletes, 10 male intercollegiate cross-country runners, and 11 normal males at angular velocities of 271, 375, 472 and 583 deg/sec. A modified Cybex II isokinetic dynamometer was used for all data collection. The dominant leg of each subject was tested at all four test velocities and the non-gravity-corrected peak torque/kg values of the hamstrings and quadriceps femoris as well as the H/Q peak torque ratios were analyzed. The…results were: (1) Sprinters produced a significantly greater (p < 0.05) values for both hamstrings and quadriceps femoris than normals at 271, 472, and 583 deg/sec and significantly greater quadriceps femoris peak torque/kg than cross-country runners at 583 deg/sec. (2) Cross-country runners produced significantly greater peak torque/kg hamstring values than normals at 472 deg/sec. (3) No significant differences were found for H/Q peak torque ratios between groups at each speed or between speeds for each group. (4) The absolute differences between peak torque/kg values of the hamstrings and the quadriceps femoris decreased with increasing velocity for all groups. (5) Cross-country runners' hamstring peak torque/kg values exceeded the quadriceps peak torque/kg values at 583 deg/sec.
Keywords: Peak torque (quadriceps femoris and hamstring), high-velocity ratio sprinters, cross-country runners
Abstract: The purpose of this study was to assess the intratester reliability of torque variables of the hip and knee extensor musculature during an isokinetic, concentric contraction in a closed kinematic chain. Nineteen healthy subjects (10 females, 9 males, mean age 24 ± 4) were tested on the Kin-Com on two occasions, exactly 1 wk apart. The subjects were stabilized in the supine position with their dominant foot fixed to a foot plate, in approximately 115 deg of hip and knee flexion, and asked to extend to full hip and knee extension. Testing was performed at 30, 120, and 210 deg/sec.…Reliability was determined on the female group (n = 10), the male group (n = 9), and the combined group (n = 19). Torque measurements of the hip and knee extensors in a closed kinematic chain using this protocol were reliable except for the male group at 30 deg/sec. The intraclass correlation coefficients (lCCs) for combined group torque values were comparable to those of previous studies performed on the knee extensors in an open kinematic chain. These results indicate that isokinetic concentric testing of the hip and knee extensors in a closed kinematic chain can be reliable when this protocol is used.
Abstract: This study examined the effects of four different lower extremity kinetic chain states (KCS) on spinal flexor and extensor muscle performance during concentric isokinetic activity. The KCS involved different combinations of joint stabilization: ankle, knee, and hip/pelvis (Closed), knee and hip/pelvis (Open 1), ankle and hip/pelvis (Open 2), and hip/pelvis (Open 3). Twenty volunteer subjects (11 males, 9 females; age range 15–23 yr) were tested on a Cybex TEF isokinetic spinal dynamometer at the speed of 60 deg/sec in a sequential repeated measures design of four different test sessions, each separated by a period of 48 h. Testing involved five…maximal spinal flexion/extension repetitions through a 0–60 deg motion arc as peak torque data were collected by the device's computer system. ANOVA failed to show significant differences between test motions (p = 0.668) or the factors of test motion x KCS (p = 0.955), but did show a difference between individual KCS (p < 0.001). Post hoc Scheffe tests showed significant differences between Closed and all Open KCS, between Open 3 and the other Open KCS, but failed to show a difference between the Open 1 and Open 2 KCS. It was concluded that a Closed KCS had a greater influence on lumbar muscle output than Open KCS and that the output influence decreased as KCS became progressively less constrained.
Keywords: Kinetic chain states (KCS), lumbar extensors/flexors, peak torque assessment
Abstract: A 21-year-old male college baseball pitcher with a diagnosis of “impingement syndrome” was seen in sports physical therapy for a rehabilitation program. Physical evaluation revealed restricted internal rotation flexibility, diminished external rotator and scapular stabilizer strength, and a mechanical flaw in his throwing technique. He was placed on an isokinetic strengthening regimen for his rotator cuff, a flexibility routine to address internal rotator tightness, and a progressive throwing program. Ten weeks following this program, the patient was asymptomatic, exhibited “normal” isokinetic and flexibility parameters, and was able to return to competition without pain or restriction in function.