Isokinetics and Exercise Science - Volume 2, issue 4
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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 relation between joint distension and juxtaarticular muscle function is reviewed with focus on human studies. The neurophysiological background and the methods used in humans are examined. The importance of treating the underlying cause for joint distention is stressed. especially regarding chronic compared with acute exudates. Aspiration of acute exudates is recommended in some cases to minimize juxtaarticular muscle wasting. Possible function studies are outlined.
Keywords: Neural inhibition, articular effusion, muscular function
Abstract: The purpose of this study was to examine the effects of two proprioceptive neuromuscular facilitation (PNF) stretching procedures on flexibility and muscular strength. Subjects were 41 females enrolled in dance fitness classes at a large state university. One class was designated as the control, whereas the other class subjects were randomly assigned to a slow reversal. (SR) PNF group (n = 12) or a contract-relax (CR) PNF group (n = 10). The treatment groups participated in a supervised PNF program three times per week for 7 weeks. All subjects were pre- and posttested for flexibility and strength of the hip…extensors. Adjusted posttest mean flexibility scores did not significantly differ between groups (F(2.37) = 2.12, P > 0.05). However, the SR and CR groups showed 6.2% and 6.8% mean increases in hip flexibility, respectively, whereas the control group showed only a 0.7% mean increase. Adjusted posttest scores of strength were significantly different between groups (F(2.37) = 7.35, P < 0.05). Tukey's post hoc test showed significant differences between the control and two treatments (P < 0.05), but no significant difference between the two treatment groups (P > 0.05). The results of this study suggest that SR and CR PNF stretching procedures may be effective for increasing flexibility and developing muscular strength for some groups. Such information is of practical importance to coaches, athletic trainers, and exercise specialists interested in maintaining and increasing strength through the use of PNF stretching procedures.
Keywords: Proprioceptive neuromuscular facilitation techniques, hip range of motion and muscular strength, hip extensors
Abstract: The purpose of this study was to investigate, using the YMCA Bench Press test, the absolute, dynamic, upper body muscular endurance (ME) of inactive men and women 20–49 years of age. The subjects were 215 men and 151 women. Data were factored by gender, and decade of life and compared using a two-way analysis of variance with 0.05 chosen as the level of significance. The Tukey-Kramer test was used to locate significant post hoc differences. Results indicated women performed more repetitions than men (P = 0.018) and fifth decade participants performed fewer repetitions than their third and fourth decade counterparts…(P = 0.020). There was no significant (P > 0.05) age by gender interaction concerning bench press performance. We conclude that inactive, fifth decade men and women are likely to possess reduced absolute, dynamic upper body ME when compared with their younger counterparts, and that inactive adult women are likely to perform more repetitions in the YMCA bench press test than inactive adult men.
Keywords: Dynamic muscular endurance, YMCA Bench Press Test, cross-sectional study
Abstract: The purposes of this study were to examine the relationship between physical activity level (PAL) and isometric peak torque (PT) of the knee extensor (KE) and ankle plantar flexor (PF) muscles of people 51 to 90 years of age, and to examine changes in PAL and PT by decade of age for men and women. Isometric PT of the KE and PF was measured using the Minnesota System for Isometric Muscle Strength (SIMS). Seventy-nine healthy subjects (39 men and 40 women) were tested. PT decreased as age increased. The correlation between PAL and PT was significant for both muscle groups…for all 79 subjects. The women showed a progressive decline in both PAL and PT. The PAL of men changed very little until the age of 80, and decreased rapidly between the 8th and 9th decades of life. PT appeared to gradually decrease up to age 80 and decline more rapidly between the 8th and 9th decades of life. Thus PAL and PT of the knee extensors and ankle plantar flexors decrease in a similar pattern with age.
Keywords: Knee extensors, ankle plantar flexors, activity level, geriatric population
Abstract: The ability to obtain adequate strength assessment of young children in field-based settings is difficult because of limited instrumentation, differentiation between absolute and relative strength, frequency of zero scores, and adequacy of testing instruments. More precise testing devices are needed if teachers or clinicians are to make more informed decisions concerning the development of strength in children. The purpose of this investigation was to determine the objectivity and reliability of the measurements obtained by the Nicholas Manual Muscle Tester from elementary school-aged children. The objectivity correlation coefficients ranged from 0.49 to 0.95 for two judges and 0.33 to 0.91 for…a single judge. Internal consistency reliability ranged from 0.75 to 0.95 for three trials and from 0.49 to 0.91 for a single trial. Stability reliability ranged from 0.78 to 0.96 for 2 days and from 0.64 to 0.93 for a single day. It was concluded that three trials produced the most reliable measures for children and that specific actions using large muscle groups, such as the quadricep extension, will yield the most reliable measures.
Keywords: Reliability, objectivity, muscle strength, children
Abstract: We report 14 separate studies of the mechanical and/or physiological performance reliabilities of selected isokinetic dynamometers, including the Biodex, Cybex 340, Cybex Liftask, Cybex TORSO, Cybex TEF, and Merac systems. A total of 171 volunteer subjects (85 females, 86 males; age range 16–34 years) were randomly assigned to a dynamometer for physiological reliability testing. Testing consisted of five maximal performance efforts across a velocity spectrum. Each session was preceded by an isokinetic and cardiovascular warm-up, through a controlled range of knee, spine, or lifting motion in a test/retest design separated by 48 hours. Mechanical reliability testing consisted of five repetitions…of dropping a certified load through a controlled motion arc across a velocity spectrum, also under the test/retest paradigm. Intraclass correlation statistical procedures showed significant levels of mechanical and physiological test/retest reliability for each of the tested dynamometer systems. Within the limitations of the study, the selected isokinetic devices demonstrated reliability for performance measurement during concentric isokinetic, eccentric isokinetic, or concentric isotonic functions, depending on the specific device.
Abstract: The purpose of this study was to assess the test-retest concentric reliability of the LIDO Active isokinetic dynamometer. Twenty subjects performed knee extension and flexion on two separate days, 48 hours apart. Peak torque (PT), average work (AW), average power (AP) and joint angle at peak torque (JA) were measured at 60, 180, 300 and 400 degrees per second (deg/sec). Pearson product moment (r) correlations between day 1 and day 2 for PT, AW, and AP ranged from 0.90 to 0.99. The JA r values ranged from 0.09 to 0.92. Extension paired t-tests revealed that mean values for PT, AW,…AP and JA on day 1 were not significantly (p < 0.05) different from mean values on day 2, with the exception of AW at 300 deg/sec. Flexion t tests indicated that PT values were not different. Average work was significant at all velocities except 300 deg/sec, while AP and JA were significant at 180 and 60 deg/sec, respectively. It was concluded that the LIDO Active isokinetic dynamometer is a reliable instrument to assess concentric isokinetic strength.
Abstract: The reliability of the specially adapted Orthotron KT-II, with stress indicators, has been examined as compared with the Cybex II, which is the established mechanism for isokinetic testing of the knee. Two testing speeds were used with the HUMAC/software system for each machine: 60 deg/sec, and 240 deg/sec. Forty-four healthy men and women, both athletes and nonathletes, with no previous knee injuries, were selected from a university population. Subjects were randomly assigned to one of two groups. Subjects tested once on each machine, with at least a 48-hour recovery period between testing sessions. A two-way analysis of variance was conducted…for type of machine and order of machine testing. Sample means for nine measurements of muscular performance, selected from the Humac menu, were compared. What may be significant clinical and statistical differences were found in four of the measurements: (1) work per repetition to body weight ratio; (2) fatigue index; (3) force decay; and (4) total range of motion. Due to problems in achieving proper joint-axis alignment on the Orthotron KT-II, as compared with the Cybex II, position parameters were manipulated mathematically such that both machines had the same zero baseline for reference. Significant amounts of variance were attributed to differences in height, weight, sex, and activity status among subjects in the two groups. The inherent differences between a mechanical hydraulic system such as the Orthotron KT-II, compared with an electrically powered system such as the Cybex II seemed to be most evident in the measurement of fatigue index. Test scores on the Orthotron KT-II tended to show less fatigue than the Cybex II over the same test interval. All other measurements of muscular performance showed insignificant differences between the sample means on the two machines.
Keywords: Orthotron KT-II, software analysis, comparison to Cybex II