Effects of fasting on critical velocity and anaerobic capacity determination in running rats

The non-invasive critical power model suggested for aerobic/anaerobic evaluation of human beings was adapted for rats in our Laboratory. The aim of the present study was to verify the effects of 12-hours fasting on the critical velocity (CV) and the anaerobic running capacity (ARC) determination in sedentary rats. 11 adult Wistar rats (90 days old, weighing 395.5 ± 17.6g) were submitted to four exercise tests at 25, 30, 35 and 40m/min (with 48 hours of interval), performed randomly and continuously until exhaustion, for the CV and ARC estimations. The protocol was executed with the rats in the fed state and after 12-hours fasting. The hyperbolic curve velocity versus time to exhaustion (tlim) was linearized to V = CV + ARC/tlim, where the CV and ARC were the linear and slope coefficients, respectively. For comparison of the parameters obtained in the fed state and after fasting, the Student t test for dependent measures was used (p\u3c0.05). The CV (m/min) and ARC (m) were 25.5 ± 1.5 and 21.8 ± 16.4 m in fed state and 22.5 ± 4.2 and 25.9 ± 14.0 m after fasting. The linear regression showed significant values (R2=0.85±0.07 in fed state and 0.88±0.09 after fasting). The 12-hours fasting modified the CV without changing ARC. The results indicate that there is a caution need with the alimentary condition of running rats previously to evaluation test. The physiological characteristics can mask the determination of the aerobic condition, resulting in the inadequate exercise prescription based on the parameters estimated by the non-invasive protocol

Anaerobic And Aerobic Performances In Elite Basketball Players.

THE PURPOSE OF THIS STUDY WAS TO PROPOSE A SPECIFIC LACTATE MINIMUM TEST FOR ELITE BASKETBALL PLAYERS CONSIDERING THE: Running Anaerobic Sprint Test (RAST) as a hyperlactatemia inductor, short distances (specific distance, 20 m) during progressive intensity and mathematical analysis to interpret aerobic and anaerobic variables. The basketball players were assigned to four groups: All positions (n=26), Guard (n= 7), Forward (n=11) and Center (n=8). The hyperlactatemia elevation (RAST) method consisted of 6 maximum sprints over 35 m separated by 10 s of recovery. The progressive phase of the lactate minimum test consisted of 5 stages controlled by an electronic metronome (8.0, 9.0, 10.0, 11.0 and 12.0 km/h) over a 20 m distance. The RAST variables and the lactate values were analyzed using visual and mathematical models. The intensity of the lactate minimum test, determined by a visual method, reduced in relation to polynomial fits (2nd degree) for the Small Forward positions and General groups. The Power and Fatigue Index values, determined by both methods, visual and 3rd degree polynomial, were not significantly different between the groups. In conclusion, the RAST is an excellent hyperlactatemia inductor and the progressive intensity of lactate minimum test using short distances (20 m) can be specifically used to evaluate the aerobic capacity of basketball players. In addition, no differences were observed between the visual and polynomial methods for RAST variables, but lactate minimum intensity was influenced by the method of analysis.42137-4

Adaptation of invasive and non-invasive protocols to aerobic and anaerobic specific evaluation in female basketball players

OBJECTIVE: To adapted the critical velocity (CV), RAST test and lactate minimum (LM) to evaluation of female basketball players. METHODS: Twelve well-trained female basketball players (19 ± 1yrs) were submitted to four intensities running (10 - 14 km/h) at shuttle exercise until exhaustion, applied on alternate days. The linear model 'velocity vs. 1/tlim' was adopted to determine the aerobic (CV) and anaerobic (CCA) parameters. The lactate minimum test consisted of two phases: 1) hiperlactatemia induction using the RAST test and 2) incremental test composed by five shuttle run (20-m) at 7, 8, 9, 10, and 12 km/h. Blood samples were collected at the end of each stage. RESULTS: The velocity (vLM) and blood lactate concentration at LM were obtained by two polynomial adjustments: lactate vs. intensity (LM1) and lactate vs. time (LM2). ANOVA one-way, Student t-test and Pearson correlation were used for statistical analysis. The CV was obtained at 10.3 ± 0.2 km/h and the CCA estimated at 73.0 ± 3.4 m. The RAST was capable to induce the hiperlactatemia and to determine the Pmax (3.6 ± 0.2 W/kg), Pmed (2.8 ± 0.1 W/kg), Pmin (2.3 ± 0.1 W/kg) and FI (30 ± 3%). The vLM1 and vLM2 were obtained, respectively, at 9.47 ±0.13 km/h and 9.8 ± 0.13 km/h, and CV was higher than vLM1. CONCLUSION: The results suggest that the non-invasive model can be used to determine the aerobic and anaerobic parameters. Furthermore, the LM test adapted to basketball using RAST and progressive phase was effective to evaluate female athletes considering the specificity of modality, with high success rates observed in polynomial adjustment 'lactate vs. time' (LM2).OBJETIVO: Adaptar os protocolos de velocidade crítica (Vcrit), RAST Test e Lactato Mínimo (LM) à especificidade do basquetebol feminino. MÉTODOS: Doze basquetebolistas bem treinadas (19 ± 1 anos) foram avaliadas pelo modelo velocidade crítica, composto por quatro intensidades (10,8, 12,0, 13,0, 14,5 km/h) de corridas vai-vem até exaustão, aplicadas em dias alternados. O modelo linear 'velocidade versus 1/tlim' foi adotado para determinação de parâmetros aeróbio (Vcrit) e anaeróbio (CCA). O LM foi composto por duas fases: 1) indução hiperlactacidêmica, caracterizada pelo RAST adaptado, e 2) fase progressiva, composta por cinco estágios de 3 minutos em corridas vai-vem de 20 m (7 a 12km/h), com coletas de sangue ao final de cada estágio. RESULTADOS: A velocidade (vLM) e a concentração do lactato mínimo foram obtidas pelos ajustes polinomiais 'lactato versus intensidade' (LM1) e 'lactato versus tempo' (LM2). A ANOVA one-way, teste t-Student e correlação de Pearson foram utilizados na análise estatística. A Vcrit foi obtida a 10,3 ± 0,2 km/h e a CCA estimada em 73,0 ± 3,4 m. O RAST foi capaz de induzir a hiperlactacidemia e determinar potências máxima (3,6 ± 0,2 W/kg), média (2,8 ± 0,1 W/kg), mínima (2,3 ± 0,1W/kg) e o índice de fadiga (30 ± 3%). A vLM1 e vLM2 foram obtidas, respectivamente, a 9,47 ± 0,13 e 9,8 ± 0,13km/h, sendo a vLM1 menor que a Vcrit. CONCLUSÕES: Os resultados sugerem que o modelo específico não invasivo pode ser utilizado para determinar parâmetros aeróbios e anaeróbios de basquetebolistas e, assim como em outras modalidades, a Vcrit superestima as intensidades de LM. Além disso, a adaptação do LM ao basquetebol feminino utilizando o RAST e a fase progressiva em exercício vai-vem foi efetiva para avaliar as atletas respeitando a especificidade da modalidade, com elevado percentual de sucesso no ajuste polinomial 'lactato versus tempo'.17117

Running Anaerobic Sprint Test, Lactate Minimum and Critical Velocity Protocol in Shuttle Futsal Testing

The aims of this study were to investigate whether the running anaerobic sprint test, lactate minimum and critical velocity protocol can be applied in shuttle futsal testing, and to investigate if these protocols provide related variables. Seven male welltrained futsal players were evaluated. The lactate minimum test (LacMin) consisted of three phases: a) a hyperlactatemia phase using the running anaerobic sprint test (RAST); b) recovery phase; c) an incremental shuttle test for the lactate minimum speed (LMS) determination. Successful rate (SR) was calculated for feasibility analysis. Peak, mean and minimum power and fatigue index were obtained by the RAST application (six bouts – 35 meters). The critical velocity protocol (CV) was applied through three exhaustive shuttle tests (12, 13 and 14 km/h) with distances of 20 meters. Critical velocity (Cv) and anaerobic running capacity (ARC) were analysed by the linear (velocity vs.1/tlim) and hyperbolic (time vs.velocity) models. Fits of regression (R²) were considered as the main result for feasibility analysis of CV. ANOVA showed a difference between linear (11.04 ±0.55 km/h) and LMS (9.67 ±0.50 km/h), and no significant correlation was observed between them. High SR (85.71%) was observed for LacMin, and high R² for CV (linear-R² = 0.99 ±0.04; hyperbolic-R² = 0.98 ±0.02).Overall, the RAST, LacMin and CV can be successfully applied in shuttle futsal testing, nonetheless, precaution is necessary since the test results were not related

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

Anaerobic and aerobic performances in elite basketball players

The purpose of this study was to propose a specific lactate minimum test for elite basketball players considering the: Running Anaerobic Sprint Test (RAST) as a hyperlactatemia inductor, short distances (specific distance, 20 m) during progressive intensity and mathematical analysis to interpret aerobic and anaerobic variables. The basketball players were assigned to four groups: All positions (n=26), Guard (n= 7), Forward (n=11) and Center (n=8). The hyperlactatemia elevation (RAST) method consisted of 6 maximum sprints over 35 m separated by 10 s of recovery. The progressive phase of the lactate minimum test consisted of 5 stages controlled by an electronic metronome (8.0, 9.0, 10.0, 11.0 and 12.0 km/h) over a 20 m distance. The RAST variables and the lactate values were analyzed using visual and mathematical models. The intensity of the lactate minimum test, determined by a visual method, reduced in relation to polynomial fits (2nd degree) for the Small Forward positions and General groups. The Power and Fatigue Index values, determined by both methods, visual and 3rd degree polynomial, were not significantly different between the groups. In conclusion, the RAST is an excellent hyperlactatemia inductor and the progressive intensity of lactate minimum test using short distances (20 m) can be specifically used to evaluate the aerobic capacity of basketball players. In addition, no differences were observed between the visual and polynomial methods for RAST variables, but lactate minimum intensity was influenced by the method of analysis421137147FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPsem informaçã