Physiological comparisons among three maximal treadmill exercise protocols in trained and untrained individuals

Abstract

The present investigation was undertaken to examine whether maximal oxygen uptake (VO2max) and anaerobic threshold (AT) measured during incremental treadmill exercise would be affected by the exercise protocol in trained and untrained individuals. Fifteen untrained men, 10 untrained women, and 12 trained individuals participated in this study. The Astrand, Bruce, and Costill/Fox protocols were selected for comparison. Each subject was tested using all three protocols and the three tests were conducted in a randomized counterbalanced order. During each test, oxygen uptake was measured every 30 s and the test was terminated according to the standard criteria. The VO2max was determined by averaging the two consecutive highest measurements, whereas AT was determined using ventilatory parameters following the V-slope technique. The Astrand, Bruce, and Costill/Fox protocols produced test durations of 9.8 (SEM 0.5), 12.4 (SEM 0.4), and 4.9 (SEM 0.3) min, respectively, in the untrained men, 9.0 (SEM 0.8), 11.0 (SEM 0.6), and 5.3 (SEM 0.6) min, respectively, in the untrained women, and 14.5 (SEM 0.5), 17.0 (SEM 0.5) and 10.4 (SEM 0.4) min, respectively, in the trained men. In the untrained men and women, no differences in VO2max were observed among the three different protocols, but AT was lower when using the Bruce compared to the Astrand protocol. In the trained men, VO2max and AT were lower when using the Bruce protocol than either the Astrand or Costill/Fox protocols. In conclusion, VO2max measured during treadmill exercise is not affected by the protocol of the test and using a running protocol of short duration (i.e. about 5 min) could be a time-efficient way of assessing VO2max in healthy untrained subjects. In trained subjects, however, a protocol consisting of running with small increments in gradient is effective in eliciting a higher VO2max. The lower AT associated with the Bruce protocol seen in both untrained and trained groups suggests this aerobic parameter is protocol dependent and this protocol dependency is not affected by training status.

Avaliação da capacidade máxima de exercício: uma revisão sobre os protocolos tradicionais e a evolução para modelos individualizados

“…This fact presents clinical importance, since the evolution of the functional capacity of the individuals before and after they have been submitted to treatments and/or surgeries, was assessed in relation to the time of remaining in the protocols. More recently and corroborating this possibility, Kang et al (28) analyzed three protocols on treadmill in 25 sedentary and 12 trained individuals and did not observe significant alterations in the O 2max for the sedentary ones, despite the difference verified in the test times. These expressive differences between protocols may compromise the analysis of the obtained results in a comparative perspective.…”

Comparação de protocolos de corrida para determinação de diferentes limiares

“…Assim, especula-se que esta resposta metabólica esteja associada ao nível de treinamento dos sujeitos avaliados e, que em atletas altamente treinados, essa resposta seja distinta. Outro fator relevante é que ambos os protocolos incrementais utilizam a corrida como forma de exercício, promovendo estímulos muito próximos, o que pode ser o motivo da ausência de diferenças significativas entre os limiares metabólicos 11 .…”

“…Alguns protocolos manipulam a duração de cada estágio incremental, a inclinação ou os intervalos entre cada estágio incremental. Na literatura verificam-se estudos que compararam protocolos com diferentes durações dos está-gios de corrida incremental 5,10 , e protocolos com incrementos distintos -velocidade e inclinação da esteira 11 . No entanto, faz-se necessária a realização de estudos que comparem os efeitos de diferentes intervalos entre os estágios de velocidade de protocolos incrementais de corrida na determinação de limiares.…”

Effects of concurrent strength and endurance training on middle distance races

“…Se realizó un test de esfuerzo en tapiz rodante con pendiente de 0.5%. Se aplicó un incremento en rampa para prevenir el cese prematuro del ejercicio por fatiga originada por escalones demasiado largos (Kang et al 2001). Los incrementos fueron adaptados de forma individual tratando que la duración del test fuera de entre 10-12 minutos (Buchfuhrer et al 1983).…”