No abstract

BackgroundAthletic competition has been a source of interest to the scientific community for many years, as a surrogate of the limits of human ambulatory ability. One of the remarkable things about athletic competition is the observation that some athletes suddenly reduce their pace in the mid-portion of the race and drop back from their competitors. Alternatively, other athletes will perform great accelerations in mid-race (surges) or during the closing stages of the race (the endspurt). This observation fits well with recent evidence that muscular power output is regulated in an anticipatory way, designed to prevent unreasonably large homeostatic disturbances.Principal FindingsHere we demonstrate that a simple index, the product of the momentary Rating of Perceived Exertion (RPE) and the fraction of race distance remaining, the Hazard Score, defines the likelihood that athletes will change their velocity during simulated competitions; and may effectively represent the language used to allow anticipatory regulation of muscle power output.ConclusionsThese data support the concept that the muscular power output during high intensity exercise performance is actively regulated in an anticipatory manner that accounts for both the momentary sensations the athlete is experiencing as well as the relative amount of a competition to be completed.

Energy expenditure during high-intensity cycling seems: 1) to be expended in a manner that allows the athlete to preserve an anaerobic energetic contribution throughout an event, 2) does not appear to have a large learning effect in already well trained cyclists, and 3) anaerobic energy expenditure may be the performance discriminating factor among groups of athletes.

Power Poles are specially constructed, rubber-tipped ski poles designed for use during walking. Using Power Poles simulates the arm motion of cross-country skiing, thus increasing the muscle mass used during walking. This study investigated the potential increases in exercise intensity and energy cost associated with the use of walking poles. Thirty-two apparently healthy volunteers (16 men and 16 women) between the ages of 19 and 33 years participated. Each completed a treadmill maximal oxygen consumption (VO2max) test and two randomly assigned, submaximal walking trials (one with poles and one without poles) on separate days. Each walking trial was conducted on a level treadmill, for 20 minutes, at an identical self-selected pace. Expired gases, heart rate in beats per minute (bpm), and ratings of perceived exertion (RPE) were recorded each minute. Results between trials were compared using repeated measures analysis of variance and Tukey's post hoc tests. It was found that walking with poles resulted in an average of 23% (4.4 ml.kg-1.min-1) higher VO2, 22% higher caloric expenditure (1.5 kcal.min-1), and 16% (18 bpm) higher heart rate responses compared to walking without poles on a treadmill. RPE values averaged 1.5 units higher with the use of the poles, and the pattern of responses between conditions was similar for men and women. It is concluded that the use of Power Poles can increase the intensity of walking at a given speed and, thus, may provide additional training benefits to walkers.

This study supports the hypothesis that RPE increases similarly in relation to relative distance, regardless of the distance performed, and it suggests that the perception of effort has scalar properties.