Isokinetics and Exercise Science - Volume 17, issue 1

Authors: Caruso, John F. | Monda, Julie K. | Ramey, Elizabeth | Hastings, Lori P. | Coday, Michael A. | McLagan, Jessica R. | Wickel, Eric E.

Article Type: Research Article

Abstract: To assess blood lactate and performance variables obtained from high-speed exercise performed on a device (Impulse Training Systems; Newnan GA) that imposes loads without gravitational resistance, subjects (n = 45) completed two tonic and two phasic workouts. Each high-speed workout entailed two 60-second sets of seated knee- and hip-extension repetitions separated by a 90-second rest period. Pre- and five minutes post-exercise, lactate concentration was measured from a fingertip blood drop with a …calibrated analyzer (Accusport, Sports Resource Group, Hawthorne, NY). Mean blood lactate values were compared with a 2(contractile mode: tonic, phasic) × 2(time) × 2 (gender) ANOVA, with repeated measures applied to workout mode and time. Resistance exercise performance variables were assessed with 2 (contractile mode: tonic, phasic) × 2 (gender) ANOVAs. With α ⩽ 0.05, results showed a time (post > pre) effect for blood lactate. Exercise performance values were impacted by workout mode and gender, yet those independent variables had no impact on blood lactate. Results concur with prior resistance exercise studies that show significant blood lactate increases over time. Additional inquiry is warranted as to why gender and workout mode influenced resistance exercise performance variables, but did not impact blood lactate. Show more

Keywords: Strength training, metabolic acidosis, fatigue

DOI: 10.3233/IES-2009-0319

Citation: Isokinetics and Exercise Science, vol. 17, no. 1, pp. 1-7, 2009

Authors: Mbada, C.E. | Ayanniyi, O.

Article Type: Research Article

Abstract: Background and objective: Identifying methods of accurately predicting endurance capacity of the back extensor muscles is of immense value to both patients and clinicians. This study aimed to develop a multiple regression equation using demographic and anthropometric measurements to predict back endurance and to investigate the association between performed back endurance results and back endurance predictions. Materials and methods: 376 healthy women and men aged 21–62 y were recruited consecutively. All participants underwent the …Biering-Sørenson test of Static Muscular Endurance. Height and weight were measured using standard procedures. Percentage body fat was estimated using bioelectrical impedance analysis. Body mass index, lean body mass and body fat mass were calculated. Based on these a regression model was used to generate predictive equation for endurance time. Results: The final regression model which included demographic and anthropometric variables could account for 43% of the variability in back muscle endurance. Pearson's product correlation coefficient for the association between performed static endurance and the predicted endurance were (r = −0.129; p = 0.074) and (r = 0.671; p = 0.000) for male and female participants respectively. Paired t-test showed significant difference (p = 0.000) between the performed static endurance and predicted endurance among the male participants but not among the female counterparts (p = 0.959). Endurance time of males (119 ± 49.8 secs.) was significantly greater (p = 0.014) than that of the females (106 ± 47.6 secs.). Conclusion: Regression equation seems to be moderately valid in predicting endurance time of the back extensors among females only. We conclude that simple anthropometric measures cannot accurately predict back endurance without significant errors. The larger error of prediction obtained for the male participants could be indicative of an increasing influence of motivational/psychosocial factors that are known to be independent of motor ability in physical performance testing. Show more

Keywords: Static endurance, back extensor muscles, Sørenson test, endurance time, predictive equation

DOI: 10.3233/IES-2009-0330

Citation: Isokinetics and Exercise Science, vol. 17, no. 1, pp. 9-14, 2009

Authors: Bohannon, Richard W.

Article Type: Research Article

Abstract: This retrospective study examined the initial therapy notes of home-care patients to determine the ability of manual muscle testing (MMT) to identify muscle weakness and explain functional independence. Manual muscle test scores for trunk flexion and 3 lower limb muscle actions (hip flexion, knee extension, and ankle dorsiflexion) were obtained bilaterally as was independence in sit-to-stand and walking 50 feet. All 31 patients (mean age 72.8) demonstrated muscle weakness in some tested muscle group. Less than …maximum MMT scores were most common for hip flexion (100%) and least common for knee extension (51.6%). All but 2 individual and combined strength measures correlated significantly with both sit-to-stand and walking independence. The correlations ranged from 0.308 to 0.748. Based on its ability to identify weakness and explain functional independence, MMT appears to be an appropriate measure for use with patients seen in a home-care setting. Show more

Keywords: Muscle strength, measurement, physical therapy, activities of daily living

DOI: 10.3233/IES-2009-0326

Citation: Isokinetics and Exercise Science, vol. 17, no. 1, pp. 15-17, 2009

Authors: Lappalainen, Zekine | Kilinc, Fatih | Lappalainen, Jani | Atalay, Mustafa

Article Type: Research Article

Abstract: Circadian rhythms are known to influence muscular performance and regulate leptin hormone secretion, which assists in the regulation of body weight and energy homeostasis. In this study we examined the time-of-day effect on skeletal muscle eccentric contractile properties and the response of serum leptin to acute eccentric exhaustive isokinetic exercise. Male subjects (n = 26) performed a bout of exhaustive eccentric exercise on an isokinetic dynamometer in the morning or late afternoon time on different …days. The test was repeated after 7–10 days at different time-of-day. Blood samples were collected at baseline and immediately after exercise for determination of serum leptin. Leg extensor muscle torque and work parameters were recorded, and compared with the time-of-day. Maximal eccentric torque values were not significantly affected by time-of-day. The maximal work performed during single repetition as well as total work values were significantly higher in the afternoon time. Leptin levels significantly decreased after exercise, but no time-of-day effect on serum leptin could be observed. Diurnal variations during short-term isokinetic exhaustive eccentric exercise seem to reflect muscle work capacity, with higher contractile efficiency towards the evening time. Although short-term exhaustive eccentric exercise decreased serum leptin, the levels did not to have a significant diurnal variation. Show more

Keywords: Diurnal variation, eccentric exercise, leptin, muscle work

DOI: 10.3233/IES-2009-0327

Citation: Isokinetics and Exercise Science, vol. 17, no. 1, pp. 19-25, 2009

Authors: Leunkeu, Angeline Nsenga | Gayda, Mathieu | Nigam, Anil | Lecoutre, Noël | Ahmaidi, Said

Article Type: Research Article

Abstract: The aims of this study were to: 1) study the cardiopulmonary responses during exhaustive isometric contraction in cerebral palsy (CP) children vs. apparently normal (AN) children 2) to study the relationship between muscle endurance and maximal O_{2} uptake (peak VO_{2} ) in CP children. Eight CP children (GMFC 1 to 2) and 8 AN children underwent a graded cycle exercise test and a quadriceps force and endurance assessment with cardiopulmonary measurement on an …isokinetic dynamometer. During isometric contraction, muscle endurance did not differ between the groups but a higher O_{2} uptake was shown in the CP group. Moreover in this group, peak VO_{2} was correlated with muscle strength (R = 0.77, P < 0.05) and endurance (R = 0.68, P < 0.05). Cerebral palsy children have a higher O_{2} uptake during isometric endurance testing despite a lower absolute isometric force but their quadriceps endurance is not impaired after normalization with muscle mass and time. Additionally, quadriceps strength and endurance in CP children were in relationship with their peak VO_{2} . This higher O_{2} uptake is probably due to coactivation and/or cocontraction during exhaustive quadriceps isometric contraction. Show more

Keywords: Children, cerebral palsy, cardiorespiratory data, isometric contraction, quadriceps

DOI: 10.3233/IES-2009-0328

Citation: Isokinetics and Exercise Science, vol. 17, no. 1, pp. 27-33, 2009

Authors: Edouard, Pascal | Calmels, Paul | Degache, Francis

Article Type: Research Article

Abstract: Objective: To study the influence of gravitational correction on the internal (IR) and external rotators (ER) shoulder strength. Methods: The IR and ER isokinetic strength, measured in 30° scapation, was evaluated concentrically at 60 and 240°/s and eccentrically at 60°/s in 33 healthy volunteers. Strength scores were expressed either by incorporating gravitational correction (GC) or without it. Results: With GC, IR strength was significantly lower and ER strength significantly higher than without …incorporation of this procedure. Conclusion: The GC procedure has a significant influence on IR and ER strength and should be incorporated when strength deficits of the rotator cuff are expected. Show more

Keywords: Shoulder, isokinetic, gravity correction, external/internal strength testing

DOI: 10.3233/IES-2009-0329

Citation: Isokinetics and Exercise Science, vol. 17, no. 1, pp. 35-39, 2009

Authors: Caruso, John F. | Coday, Michael A. | Ramsey, Charles A. | McLagan, Jessica R.

Article Type: Research Article

Abstract: Objective: To examine the impact resistive exercise (RE) training has on the ability of anthropometry to predict power output from jump tests. Methods: With a matched-pairs design, subjects (n = 19) were assigned to six weeks of leg and calf press workouts. With no crossover, subjects either performed RE on a traditional seated leg press device to which free weights (FW) were added, or on a flywheel ergometer (FERG). Before and after the intervention, …subjects performed jump-based tests and were measured for anthropometric dimensions. Tests included a standing vertical jump, a repetitive four-jump protocol, and a depth jump from a platform; power outputs from each were calculated. Results: The six-week intervention weakened the correlation between anthropometry and jump-based power indices from FERG workouts, while the opposite was true for the FW group. Conclusions: While several reasons may have led to the stark group differences in the ability to account for jump-based power variance, the two most important factors appear to be the degree of workout progression and the rate RE repetitions were performed. FW subjects incurred significantly greater strength gains, as evidenced by the degree of workout progression over the intervention, versus the FERG group. The manner in which the devices operated permitted FW repetitions to occur at faster rates and was more movement-specific to jump-based tests. Thus anthropometry increased the degree of explained variance in jump-based power indices from FW workouts at the conclusion of the six-week intervention. Show more

Keywords: Free weights, flywheel ergometer, movement velocity

DOI: 10.3233/IES-2009-0331

Citation: Isokinetics and Exercise Science, vol. 17, no. 1, pp. 41-50, 2009

Authors: Anderson, Dennis E. | Madigan, Michael L. | Nussbaum, Maury A.

Article Type: Research Article

Abstract: Joint kinematics influence maximum voluntary muscular moment of force about a joint, and can thereby have substantial effects on available muscle moment during dynamic activities. A model of maximum voluntary muscle moment as a function of joint angle and angular velocity has been described previously. Originally, a computational optimization approach was used to fit this model to muscle moment data collected using an isokinetic dynamometer. To make this model more practical and accessible, an algorithm was …developed to directly determine the model parameters without requiring optimization. This algorithm was compared with the optimization method for fitting measured muscle moment data from six different lower limb exertions in 14 healthy adults. Both methods produced models that fit the measured moment data reasonably well (r^{2} typically > 0.75), and the direct calculation method reduced r^{2} only slightly compared to optimization (by an average of 1.14%). The direct calculation algorithm presented here may be preferable to the optimization approach used previously, as it displays comparable performance but requires less time and expertise to employ. Show more

Keywords: Moment-angle-angular velocity, isokinetic dynamometer, parameter estimation, computational methods

DOI: 10.3233/IES-2009-0332

Citation: Isokinetics and Exercise Science, vol. 17, no. 1, pp. 51-56, 2009