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Man to female differences in laboratory measures of muscular power
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Abstracts / Journal of Science and Medicine in Sport 20S (2017) e32–e66
136
137
Man to female differences in laboratory measures of muscular power
The relationship between low aerobic fitness and injury in the military
M. Cameron ∗ , R. Robergs
C. McDonald ∗ , P. Newman, J. Witchalls
School of Exercise Science, Sport and Health, Charles Sturt University, Australia
University of Canberra, Australia
Introduction: Understanding the specific physiology of females of different ages and fitness status during exercise will improve exercise prescription for females for sport, and also in the prevention and rehabilitation of chronic disease. Previously, we have documented a significant gender influence in a multiple regression model of determinants to short distance sprint performance. The purpose of this research was to further explore the male vs. female differences in laboratory measures of muscular power to improve our understanding of specific physiological differences between males and females during intense exercise. Methods: 49 healthy active males (n = 32) and females (n = 17) participants performed four assessments of muscle contractile function in random order, with 15 min of rest between each task. Testing consisted of (1) the isometric rate of force development (RFD); (2) isokinetic torque at different velocities; (3) a counter movement jump (CMJ); (4) a modified Wingate test from a stationary start, and (5) a 20 m running sprint with recorded split times at 2 m, 10 m and 20 m, and different interval times. Correlations between variables were performed using Pearson bivariate correlations. Differences between males vs. females for all variables were performed using independent t-tests and statistical significance was accepted at p < 0.05. Results There were large and significant differences between males vs. females for almost all variables. The more meaningful variable differences (males vs. females, respectively) were peakWatts/kg (10.5 ± 1.7 vs. 7.5 ± 1.0), time to peak power (7.8 ± 1.6 vs. 9.2 ± 2.0 s), all sprint running variables, peak torque at 180/s/kg (1.5 ± 0.03 vs. 0.92 ± 0.34), and the isokinetic torque slope (−0.32 ± 0.12 vs. −0.24 ± 0.09). Assessing correlations and slope response differences for select variables between males and females revealed evidence in support of different physiology. For example, female subjects had <50% of the male slope profile for 10–20 m sprint performance vs. peakWatts/kg (−13.02 vs. −6.043 W/kg/s), revealing the differences were more involved than simply being less physically fit. Slope differences were also seen in the isokinetic peak torque at 180◦ /s data (−79.06 vs. −115.8 N m for males vs. females). Discussion: Multiple measures of muscular power during intense exercise were very different between males and females, even when correcting for body mass differences. The power profile of females differs to males, revealing more complex physiological determinants than simply mass, fitness or body composition correction. Further research needs to be conducted to ascertain the determinants to female vs. male muscular power, and quantify differences in chronic adaptations to intense exercise training. http://dx.doi.org/10.1016/j.jsams.2017.01.159
Introduction: Injury in the military can be experienced in up to 25% of men and 50% of women. This poses a significant threat to a soldier’s health and readiness for deployment, and accounts for significant expenditure of money and resources. The physical fitness of military personnel is regularly measured with aerobic running tests despite the fact that higher running distances in training increases the risk of musculoskeletal injury. Methods: A systematic review of the literature was conducted by searching Cinahl, Scopus and Medline (via Web of Science) databases for primary research that analysed the relationship between injury incidence and physical fitness tests in any military population. Results: Twenty-two studies were included that assessed the relationship between physical fitness and injury in the military. All but one of these studies assessed the links between aerobic fitness testing and injury with running measures, 2 of which identified progressive running test formats and another 2 papers studied nonrunning aerobic fitness tests. The papers that analysed running tests (from 1.6 km to 3.2 km) found significant (p = 0.03–0.05) risk ratios for injury between 1.43 and 2.8 for those who were in the slowest quartile of run times. The progressive endurance runs showed significant (p = 0.000) risk ratios between 2.2 and 2.58 in poorly performing groups, while those who failed non-running aerobic tests were up to 1.31 times more likely to experience an injury (95% CI = 1.20–1.44). Discussion: Running tests are an estimate of maximal aerobic capacity and the results of this review suggest that low aerobic fitness, irrespective of the test type, is a risk factor for injury in the military. Running may have value for lower limb conditioning for military specificity, but the significance in terms of injury prevention appears to relate to improving aerobic fitness. If increasing aerobic fitness and decreasing soldiers’ running mileage reduces the risk of injury, then the current practice of high-load running training should be reconsidered. A more varied aerobic training program could be implemented to mitigate these risk factors. A future randomised control trial would be effective to test the benefits of non-running aerobic conditioning to meet the requirements for physical conditioning in the military, while reducing the risk of injury. http://dx.doi.org/10.1016/j.jsams.2017.01.160 138 The effectiveness of physical activity-based maintenance cardiac rehabilitation on physical activity levels and quality of life: A systematic review K. Ferrar 1,2,∗ , H. Geelan 1 , A. Gersch 1 , L. Graham 1 , A. Gray 1 , S. Gaonkar 1 1
University of South Australia, School of Health Sciences, Australia 2 Alliance for Research in Exercise, Nutrition and Activity, Sansom Institute, Australia Background: Physical activity-based cardiac rehabilitation (Phase II), which promotes lifestyle behaviour change, leads to improved clinical and behavioural outcomes, including better qual-
Abstracts / Journal of Science and Medicine in Sport 20S (2017) e32–e66
136
137
Man to female differences in laboratory measures of muscular power
The relationship between low aerobic fitness and injury in the military
M. Cameron ∗ , R. Robergs
C. McDonald ∗ , P. Newman, J. Witchalls
School of Exercise Science, Sport and Health, Charles Sturt University, Australia
University of Canberra, Australia
Introduction: Understanding the specific physiology of females of different ages and fitness status during exercise will improve exercise prescription for females for sport, and also in the prevention and rehabilitation of chronic disease. Previously, we have documented a significant gender influence in a multiple regression model of determinants to short distance sprint performance. The purpose of this research was to further explore the male vs. female differences in laboratory measures of muscular power to improve our understanding of specific physiological differences between males and females during intense exercise. Methods: 49 healthy active males (n = 32) and females (n = 17) participants performed four assessments of muscle contractile function in random order, with 15 min of rest between each task. Testing consisted of (1) the isometric rate of force development (RFD); (2) isokinetic torque at different velocities; (3) a counter movement jump (CMJ); (4) a modified Wingate test from a stationary start, and (5) a 20 m running sprint with recorded split times at 2 m, 10 m and 20 m, and different interval times. Correlations between variables were performed using Pearson bivariate correlations. Differences between males vs. females for all variables were performed using independent t-tests and statistical significance was accepted at p < 0.05. Results There were large and significant differences between males vs. females for almost all variables. The more meaningful variable differences (males vs. females, respectively) were peakWatts/kg (10.5 ± 1.7 vs. 7.5 ± 1.0), time to peak power (7.8 ± 1.6 vs. 9.2 ± 2.0 s), all sprint running variables, peak torque at 180/s/kg (1.5 ± 0.03 vs. 0.92 ± 0.34), and the isokinetic torque slope (−0.32 ± 0.12 vs. −0.24 ± 0.09). Assessing correlations and slope response differences for select variables between males and females revealed evidence in support of different physiology. For example, female subjects had <50% of the male slope profile for 10–20 m sprint performance vs. peakWatts/kg (−13.02 vs. −6.043 W/kg/s), revealing the differences were more involved than simply being less physically fit. Slope differences were also seen in the isokinetic peak torque at 180◦ /s data (−79.06 vs. −115.8 N m for males vs. females). Discussion: Multiple measures of muscular power during intense exercise were very different between males and females, even when correcting for body mass differences. The power profile of females differs to males, revealing more complex physiological determinants than simply mass, fitness or body composition correction. Further research needs to be conducted to ascertain the determinants to female vs. male muscular power, and quantify differences in chronic adaptations to intense exercise training. http://dx.doi.org/10.1016/j.jsams.2017.01.159
Introduction: Injury in the military can be experienced in up to 25% of men and 50% of women. This poses a significant threat to a soldier’s health and readiness for deployment, and accounts for significant expenditure of money and resources. The physical fitness of military personnel is regularly measured with aerobic running tests despite the fact that higher running distances in training increases the risk of musculoskeletal injury. Methods: A systematic review of the literature was conducted by searching Cinahl, Scopus and Medline (via Web of Science) databases for primary research that analysed the relationship between injury incidence and physical fitness tests in any military population. Results: Twenty-two studies were included that assessed the relationship between physical fitness and injury in the military. All but one of these studies assessed the links between aerobic fitness testing and injury with running measures, 2 of which identified progressive running test formats and another 2 papers studied nonrunning aerobic fitness tests. The papers that analysed running tests (from 1.6 km to 3.2 km) found significant (p = 0.03–0.05) risk ratios for injury between 1.43 and 2.8 for those who were in the slowest quartile of run times. The progressive endurance runs showed significant (p = 0.000) risk ratios between 2.2 and 2.58 in poorly performing groups, while those who failed non-running aerobic tests were up to 1.31 times more likely to experience an injury (95% CI = 1.20–1.44). Discussion: Running tests are an estimate of maximal aerobic capacity and the results of this review suggest that low aerobic fitness, irrespective of the test type, is a risk factor for injury in the military. Running may have value for lower limb conditioning for military specificity, but the significance in terms of injury prevention appears to relate to improving aerobic fitness. If increasing aerobic fitness and decreasing soldiers’ running mileage reduces the risk of injury, then the current practice of high-load running training should be reconsidered. A more varied aerobic training program could be implemented to mitigate these risk factors. A future randomised control trial would be effective to test the benefits of non-running aerobic conditioning to meet the requirements for physical conditioning in the military, while reducing the risk of injury. http://dx.doi.org/10.1016/j.jsams.2017.01.160 138 The effectiveness of physical activity-based maintenance cardiac rehabilitation on physical activity levels and quality of life: A systematic review K. Ferrar 1,2,∗ , H. Geelan 1 , A. Gersch 1 , L. Graham 1 , A. Gray 1 , S. Gaonkar 1 1
University of South Australia, School of Health Sciences, Australia 2 Alliance for Research in Exercise, Nutrition and Activity, Sansom Institute, Australia Background: Physical activity-based cardiac rehabilitation (Phase II), which promotes lifestyle behaviour change, leads to improved clinical and behavioural outcomes, including better qual-