Relações cineantropométricas e fisiológicas durante exercício incremental em esteira rolante

Testes incrementais em esteira rolante são muito utilizados para prescrição de treinamentos, havendo alterações fisiológicas e cinemáticas devido à natureza de incremento da intensidade do exercício. Contudo, a antropometria é um fator que não apresenta consenso na literatura. Neste sentido, os objetivos do presente estudo foram verificar o efeito de exercício incremental na concentração de lactato sanguíneo ([LAC]), e glicose ([GLI]), como também na frequência (FP) e amplitude de passadas (AP). Além disso, correlacionar valores de dados antropométricos (massa, altura, % de gordura) com as alterações existentes das [LAC] e [GLI]. Treze voluntários saudáveis realizaram teste incremental em esteira rolante (início a 8km/h, com incrementos de 1km/h a cada 3min até a exaustão). Antes e 3min após a realização do teste incremental foram registrados os valores de [LAC] e [GLI]. Durante cada intensidade do teste incremental foram realizadas avaliações da AP e FP por meio de filmagens no plano sagital. Como resultados, verificou-se que a [LAC] e [GLI] antes do teste incremental (1,94 ± 0,4mmol/L e 94,3 ± 7mg/dL, respectivamente) foram significantemente menores que os valores encontrados após o teste incremental (9,51 ± 2,7mmol/L e 126 ± 16mg/dL, respectivamente). Além disso, verificou-se aumento significante e gradativo da AP e FP ao longo do teste incremental. Correlações inversas e significantes (p Incremental treadmill tests are widely used for prescription of aerobic and anaerobic training. Physiological and kinematics parameters are changed by the progressive nature of this activity. However, there is no consensus on how anthropometric characteristics may affect the incremental test performance. Therefore, the aims of this study were (1) to verify the effects of the incremental treadmill test on the blood lactate concentration ([LAC]), glucose concentration ([GLU]), step frequency (SF) and step length (SL), and (2) to correlate anthropometric data (body mass, height, %body fat) to changes in [LAC] and [GLU]. Thirteen healthy males volunteered to this study and performed an incremental running test on a treadmill (start: 8 km/h, with progressive increases [1 km/h] at each three minute until exhaustion). [LAC] and [GLU] were registered before and 3 min after the incremental test performance. SF and SL were registered for each running speed by digital images at the sagital plane. As results, we verified that [LAC] and [GLU] before the incremental test (1.94 ± 0.4 mmol/L and 94.3 ± 7 mg/dL, respectively) were significantly lower (p < 0.05) than after the incremental test (9.51 ± 2.7 mmol/L and 126 ± 16. mg/dL, respectively). In addition, SF and SL presented significant increase (p < 0.05) throughout the incremental test. [LAC] presented inverse and significant correlations (p < 0.05) to height and body mass. Thus, an incremental treadmill running test affects kinematic (SF and SL) and physiological conditions (muscular fatigue, as consequence of the speed increase). Besides this, shorter and lighter subjects may present higher metabolite concentrations after this type of test

A 1-Year Study of Endurance Runners: Training, Laboratory Tests, and Field Tests

Purpose: To compare critical speed (CS) measured from a single-visit field test of the distance–time relationship with the “traditional” treadmill time-to-exhaustion multivisit protocol. Methods: Ten male distance runners completed treadmill and field tests to calculate CS and the maximum distance performed above CS (D′). The field test involved 3 runs on a single visit to an outdoor athletics track over 3600, 2400, and 1200 m. Two field-test protocols were evaluated using either a 30-min recovery or a 60-min recovery between runs. The treadmill test involved runs to exhaustion at 100%, 105%, and 110% of velocity at VO2max, with 24 h recovery between runs. Results: There was no difference in CS measured with the treadmill and 30-min- and 60-minrecovery field tests (P .05). A typical error of the estimate of 0.14 m/s (95% confidence limits 0.09–0.26 m/s) was seen for CS and 88 m (95% confidence limits 60–169 m) for D′. A coefficient of variation of 0.4% (95% confidence limits: 0.3–0.8%) was found for repeat tests of CS and 13% (95% confidence limits 10–27%) for D′. Conclusion: The single-visit method provides a useful alternative for assessing CS in the field

A New Direction to Athletic Performance: Understanding the Acute and Longitudinal Responses to Backward Running

Backward running (BR) is a form of locomotion that occurs in short bursts during many overground field and court sports. It has also traditionally been used in clinical settings as a method to rehabilitate lower body injuries. Comparisons between BR and forward running (FR) have led to the discovery that both may be generated by the same neural circuitry. Comparisons of the acute responses to FR reveal that BR is characterised by a smaller ratio of braking to propulsive forces, increased step frequency, decreased step length, increased muscle activity and reliance on isometric and concentric muscle actions. These biomechanical differences have been critical in informing recent scientific explorations which have discovered that BR can be used as a method for reducing injury and improving a variety of physical attributes deemed advantageous to sports performance. This includes improved lower body strength and power, decreased injury prevalence and improvements in change of direction performance following BR training. The current findings from research help improve our understanding of BR biomechanics and provide evidence which supports BR as a useful method to improve athlete performance. However, further acute and longitudinal research is needed to better understand the utility of BR in athletic performance programs