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233 Effect of pseudoephedrine and a combination of pseudoephedrine and caffeine on muscular strength performance in young active men
Do skinfolds accurately assess changes in body fat in obese adolescents?
D. Green 1*, K. Watts1, E. Davis 2,3, T. Jones 2,3, B. Beeson 4, A. Siafarikas2, L. BelF &T. Ackland 1 1The University Of Western Australia 2Princess Margaret Hospital 3Telethon Institute for Child Health Research 4Department of Radiology, King Edward Hospital
Obesity is epidemic in western societies, with particularly rapid rates of increase in the young. Various methods exist for the assessment of body composition in humans, but these have not been compared in obese adolescents. This study compared methods of body composition assessment in obese adolescents to determine whether changes in various measures of body composition as a result of exercise training were correlated. Multiple anthropometric measures (weight, height, 8MI, 8 skinfolds, waist and hip girths) and dual energy X-ray absorptiometry (DEXA) were undertaken in 26 obese adolescents (12.8 2.4 yrs) at baseline and following 8 weeks of exercise training. At baseline, there were strong relationships (p<0.001) between DEXA total fat and weight (r=0.78), 8MI (r=0.81), waist girth (r=0.75), and hip girth (r=0.83). Similar relationships existed between DEXA abdominal fat and weight (r=0.84), 8MI (r=0.75), waist girth (r=0.83), and hip girth (r=0.88). Neither skinfold sums, nor %body fat calculated using skinfold equations, were selected as independent predictors of DEXA total or abdominal fat by stepwise, hierarchical linear regression analysis. The significant reduction in DEXA abdominal fat following exercise (p<0.05) was not correlated with, or predicted by, changes in skinfolds or %body fat calculated from skinfolds. These data suggest that body fat derived from anthropometric measures is poorly predictive of abdominal and total fat derived from DEXA in obese adolescents. Furthermore, it highlights the limitations of skinfolds techniques for obese subjects, and questions the validity of their use to assess changes in body composition over time, with interventions such as exercise training.
Effect of pseudoephedrine and a combination of pseudoephedrine and caffeine on muscular strength performance in young active men.
A. Silk* & R. Weatherby Southern Cross University
The removal of both pseudoephedrine (PSE) and caffeine (CAF) from the prohibited substances list by WADA in 2004 has led to increased use of these drugs, both individually and in combination, by athletes. This research investigated whether CAF could potentiate the ergogenic effects of a dose of PSE. Ten subjects were tested on three separate occasions following the ingestion of either 120mg PSE (PSE120), 120mg PSE combined with 300mg CAF (PSECAF) or a placebo. The performance tests consisted of a maximal isometric contraction (incorporating the twitch interpolation technique for determination of muscle activation), and a fatigue test. Heart rate and blood pressure were also recorded. A repeated measures ANOVA was used to analyse the results. PSE120 was observed to significantly enhance performance in the fatigue test (p=0.027) and to increase isometric contraction torque and concurrent voluntary muscle activation, although these increases were not statistically significant. No treatment effect was observed for heart rate or blood pressure. The addition of CAF to PSE120 did not have any significant potentiative effect above PSE120 for any measured variable. It is hypothesised that the enhanced performance after the ingestion of PSE120 alone may be due to increased central nervous system stimulation, or the presence of a thermogenic response in the active muscle. It is postulated that the different mechanisms of action that PSE and CAF possess may interact in a fashion that negates the individual drugs ergogenic influences.
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D. Green 1*, K. Watts1, E. Davis 2,3, T. Jones 2,3, B. Beeson 4, A. Siafarikas2, L. BelF &T. Ackland 1 1The University Of Western Australia 2Princess Margaret Hospital 3Telethon Institute for Child Health Research 4Department of Radiology, King Edward Hospital
Obesity is epidemic in western societies, with particularly rapid rates of increase in the young. Various methods exist for the assessment of body composition in humans, but these have not been compared in obese adolescents. This study compared methods of body composition assessment in obese adolescents to determine whether changes in various measures of body composition as a result of exercise training were correlated. Multiple anthropometric measures (weight, height, 8MI, 8 skinfolds, waist and hip girths) and dual energy X-ray absorptiometry (DEXA) were undertaken in 26 obese adolescents (12.8 2.4 yrs) at baseline and following 8 weeks of exercise training. At baseline, there were strong relationships (p<0.001) between DEXA total fat and weight (r=0.78), 8MI (r=0.81), waist girth (r=0.75), and hip girth (r=0.83). Similar relationships existed between DEXA abdominal fat and weight (r=0.84), 8MI (r=0.75), waist girth (r=0.83), and hip girth (r=0.88). Neither skinfold sums, nor %body fat calculated using skinfold equations, were selected as independent predictors of DEXA total or abdominal fat by stepwise, hierarchical linear regression analysis. The significant reduction in DEXA abdominal fat following exercise (p<0.05) was not correlated with, or predicted by, changes in skinfolds or %body fat calculated from skinfolds. These data suggest that body fat derived from anthropometric measures is poorly predictive of abdominal and total fat derived from DEXA in obese adolescents. Furthermore, it highlights the limitations of skinfolds techniques for obese subjects, and questions the validity of their use to assess changes in body composition over time, with interventions such as exercise training.
Effect of pseudoephedrine and a combination of pseudoephedrine and caffeine on muscular strength performance in young active men.
A. Silk* & R. Weatherby Southern Cross University
The removal of both pseudoephedrine (PSE) and caffeine (CAF) from the prohibited substances list by WADA in 2004 has led to increased use of these drugs, both individually and in combination, by athletes. This research investigated whether CAF could potentiate the ergogenic effects of a dose of PSE. Ten subjects were tested on three separate occasions following the ingestion of either 120mg PSE (PSE120), 120mg PSE combined with 300mg CAF (PSECAF) or a placebo. The performance tests consisted of a maximal isometric contraction (incorporating the twitch interpolation technique for determination of muscle activation), and a fatigue test. Heart rate and blood pressure were also recorded. A repeated measures ANOVA was used to analyse the results. PSE120 was observed to significantly enhance performance in the fatigue test (p=0.027) and to increase isometric contraction torque and concurrent voluntary muscle activation, although these increases were not statistically significant. No treatment effect was observed for heart rate or blood pressure. The addition of CAF to PSE120 did not have any significant potentiative effect above PSE120 for any measured variable. It is hypothesised that the enhanced performance after the ingestion of PSE120 alone may be due to increased central nervous system stimulation, or the presence of a thermogenic response in the active muscle. It is postulated that the different mechanisms of action that PSE and CAF possess may interact in a fashion that negates the individual drugs ergogenic influences.
134