Critical Power Concept Adapted for the Specific Table Tennis Test: Comparisons Between Exhaustion Criteria, Mathematical Modeling, and Correlation with Gas Exchange Parameters

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)The purposes of this study were to determine and to compare the critical power concept adapted for the specific table tennis test (critical frequency - Cf) estimated from 5 mathematical models and using 2 different exhaustion criteria (voluntary and technical exhaustions). Also, it was an aim to assess the relationship between Cf estimated from mathematical models and respiratory compensation point (RCP), peak oxygen uptake ((V) over dotO(2PEAK)) and minimal intensity at which (V) over dotO(2PEAK) (f(V) over dotO(2PEAK)) appears. 9 male table tennis players [18(1) years; 62.3(4.4) kg] performed the maximal incremental test and 3-4 exhaustive exercise bouts to estimate Cfs (balls.min(-1)). The exhaustion time and Cf obtained were independent of the exhaustion criteria. The Cf from 3-parameter model [45.2(7.0)-voluntary, 43.2(5.6)-technical] was lower than Cf estimated by linear 2-parameter models, frequency-time(-1) [53.5(3.6)-voluntary, 53.5(3.5)-technical] and total ball thrown-time [52.2(3.5)-voluntary, 52.2(3.5)-technical] but significantly correlated. Cf values from 2 linear models were significantly correlated with RCP [47.4(3.4) balls.min(-1)], and Cf values of the linear and nonlinear models were correlated with f(V) over dotO(2PEAK) [56.7(3.4) balls.min(-1)]. However, there were no significant correlations between Cf values and (V) over dotO(2PEAK) [49.8(1.1)ml.kg(-1).min(-1)]. The results were not modified by exhaustion criteria. The 2 linear and non-linear 2-parameter models can be used to estimate aerobic endurance in specific table tennis tests.327503510Fundacao de Apoio ao desenvolvimento do Ensino, Ciencia e Tecnologia do Estado de Mato Grosso do Sul (Fundect) [41/100.111/2006, 41/100.187/2006, 23/200.223/2007]Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundacao de Apoio ao desenvolvimento do Ensino, Ciencia e Tecnologia do Estado de Mato Grosso do Sul (Fundect) [41/100.111/2006, 41/100.187/2006, 23/200.223/2007]CNPq [301 601/2006-2

Exercise training in the aerobic/anaerobic metabolic transition prevents glucose intolerance in alloxan-treated rats

<p>Abstract</p> <p>Background</p> <p>Ninety percent of cases of diabetes are of the slowly evolving non-insulin-dependent type, or Type 2 diabetes. Lack of exercise is regarded as one of the main causes of this disorder. In this study we analyzed the effects of physical exercise on glucose homeostasis in adult rats with type 2 diabetes induced by a neonatal injection of alloxan.</p> <p>Methods</p> <p>Female Wistar rats aged 6 days were injected with either 250 mg/kg of body weight of alloxan or citrate buffer 0.01 M (controls). After weaning, half of the animals in each group were subjected to physical training adjusted to meet the aerobic-anaerobic metabolic transition by swimming 1 h/day for 5 days a week with weight overloads. The necessary overload used was set and periodically readjusted for each rat through effort tests based on the maximal lactate steady state procedure. When aged 28, 60, 90, and 120 days, the rats underwent glucose tolerance tests (GTT) and their peripheral insulin sensitivity was evaluated using the HOMA index.</p> <p>Results</p> <p>The area under the serum glucose curve obtained through GTT was always higher in alloxan-treated animals than in controls. A decrease in this area was observed in trained alloxan-treated rats at 90 and 120 days old compared with non-trained animals. At 90 days old the trained controls showed lower HOMA indices than the non-trained controls.</p> <p>Conclusion</p> <p>Neonatal administration of alloxan induced a persistent glucose intolerance in all injected rats, which was successfully counteracted by physical training in the aerobic/anaerobic metabolic transition.</p

Muscle protein metabolism in neonatal alloxan-administered rats: effects of continuous and intermittent swimming training

<p>Abstract</p> <p>Background</p> <p>This study aimed to examine the effects of intermittent and continuous swimming training on muscle protein metabolism in neonatal alloxan-administered rats.</p> <p>Methods</p> <p>Wistar rats were used and divided into six groups: sedentary alloxan (SA), sedentary control (SC), continuous trained alloxan (CA), intermittent trained alloxan (IA), continuous trained control (CC) and intermittent trained control (IC). Alloxan (250 mg/kg body weight) was injected into newborn rats at 6 days of age. The continuous training protocol consisted of 12 weeks of swimming training in individual cylinder tanks while supporting a load that was 5% of body weight; uninterrupted swimming for 1 h/day, five days a week. The intermittent training protocol consisted of 12 weeks of swimming training in individual cylinder tanks while supporting a load that was 15% of body weight; 30 s of activity interrupted by 30 s of rest for a total of 20 min/day, five days a week.</p> <p>Results</p> <p>At 28 days, the alloxan animals displayed higher glycemia after glucose overload than the control animals. No differences in insulinemia among the groups were detected. At 120 days, no differences in serum albumin and total protein among the groups were observed. Compared to the other groups, DNA concentrations were higher in the alloxan animals that were subjected to continuous training, whereas the DNA/protein ratio was higher in the alloxan animals that were subjected to intermittent training.</p> <p>Conclusion</p> <p>It was concluded that continuous and intermittent training sessions were effective in altering muscle growth by hyperplasia and hypertrophy, respectively, in alloxan-administered animals.</p