Prediction of time to exhaustion in competitive cyclists from a perceptually based scale.

Prediction of time to exhaustion in competitive cyclists from a perceptually based scale. We have tested the validity of the estimated time limit (ETL) scale to predict an exhaustion time (T(lim)) from values stemming from incremental and randomized constant workloads tests on a cycle ergometer. Twenty-five cyclists performed 1 continuous incremental test, 1 discontinuous test with randomized workloads, and 1 constant power output test at 90% of maximal aerobic power (MAP) to exhaustion. Estimated time limits at 90% MAP during the incremental test and the test with randomized workloads were calculated from exponential relationships between power and ETL using the same 4 workloads. Real measured T(lim) during the constant power output test was converted into ETL values (called measured ETL). The differences between the calculated and measured ETLs were examined. Estimated time limits calculated at 90% MAP during the incremental and randomized tests corresponded to 14 minutes 56 seconds and 10 minutes 14 seconds, whereas measured ETL was equal to 11 minutes 19 seconds ± 3 minutes 40 seconds. The results showed a nonsignificant difference between calculated and measured ETLs. However, the mean differences between the measured ETL values during the constant test performed at the same intensity were -1.3 ± 2.9 and 0.3 ± 3.0 for the incremental and the randomized constant workloads tests, respectively. Consequently, the use of ETL calculated at 90% MAP during the test with randomized constant workloads may be preferable to predict the accurate T(lim). Moreover, it would seem that high-level cyclists, who were more consciously attuned to their bodies and their own effort sense, were more accurate in their prediction than low-level cyclists. It is concluded that the randomized constant workloads test that is both shorter and less strenuous would be more convenient for high-level athletes.

Precision in the prediction of middle distance-running performances using either a nomogram or the modeling of the distance-time relationship.

The purpose was to determine the levels of precision in the prediction of middle-distance performances in running using the modeling of the distance-time relationship and a nomogram. Official French running rankings for the men's 3,000; 5,000; and 10,000 m were scrutinized from 1996 to 2007. Only runners who competed over the 3 distances within the same year were included (n = 100). The distance-time relationship was modeled using a linear 2-parameter model from the plot of 2 performances to predict a third one. The nomogram of Mercier was also used to predict 1 performance from the use of the other 2. Actual and predicted performances were significantly different, except for the 5,000- and 10,000-m performances predicted from the nomogram (p > 0.05). Effect sizes (ESs) were lower when the performance was predicted by the nomogram (-0.25 < ES < 0.05) compared with the linear 2-parameter model (-0.99 < ES < 0.47). The predicted performances were significantly correlated to the actual performances (r > 0.46; p < 0.01). The bias ± limits of agreement for the 3,000-; 5,000-; and 10,000-m performances were 1.0 ± 12.8, -0.1 ± 6.9, and 0.1 ± 20.8% and 3.7 ± 15.5, -1.4 ± 6.2, and 2.5 ± 10.6% for prediction from the nomogram and distance-time relationship, respectively. Although the modeling of the distance-time relationship does not enable middle-running performances to be accurately predicted, the precision in the predictions from the nomogram suggests that the nomogram may be used to prescribe adapted training intensities and determine the optimal strategy during the race.

Prediction of peak oxygen uptake from age and power output at RPE 15 in obese women.

The purpose of this study was to develop a simple, convenient and indirect method for predicting peak oxygen uptake (VO2peak) from a sub-maximal graded exercise test (GXT), in obese women. Thirty obese women performed GXT to volitional exhaustion. During GXT, oxygen uptake and the power at RPE 15 (VO2peak) were measured, and VO2peak was determined. Following assessment of the relationships between VO2peak and PRPE 15, age, height and mass were made available in a stepwise multiple regression analysis with VO2peak as the dependent variable. The equation to predict VO2peak was: (1 min-1) = 1.355 - 9.920e-3 x age + 8.497e-3 x PRPE 15 (r = 0.83; SEE = 0.156 l min(-1)). This study suggests that age and PRPE 15 elicited during a sub-maximal GXT provides a reasonably accurate prediction of VO2peak in obese women.

Validity of a nomogram to predict long distance running performance.

The purpose was to test the validity of a nomogram to predict performance at distances ranging from the 10 km to the marathon. Official running rankings of the French Athletics Federation for the men's 10 km, 20 km, and marathon were scrutinized from 2002 to 2006. Performances of runners who competed in the 3 distances during the same year were noted (n = 330). Predicted performance by the nomogram was obtained for each distance from the performance at 2 other distances. Actual and predicted performances were compared by a Wilcoxon matched pairs test. The magnitude of the difference was assessed by the effect size (ES). Correlation and Bland-Altman plots were used to evaluate the association and the level of agreement between actual and predicted performances. The nomogram overestimated performance at the 10-km distance (13 seconds; p = 0.03) and underestimated performance at the 20-km distance (27 seconds; p < 0.01). The overestimation for the marathon was not significant (85 seconds; p = 0.06). Whatever the distance, ES were trivial (-0.04 < ES < 0.05). Correlations were 0.89 for the 10 km and the marathon and 0.97 for the 20 km. The limits of agreement represented 10.2, 6.1, and 13.2% of the mean of actual and predicted performances in 10 km, 20 km, and marathon, respectively. These results support the validity of the nomogram to predict performance on 10 km, 20 km, and marathon from the performance at 2 other distances. The accuracy of predictions is better when performance is interpolated. Given their validity and accuracy, interpolated predictions of the nomogram may be used to prescribe realistic training intensities during tempo runs, but also to determine the optimal strategy during the race.

Prediction of peak oxygen uptake from sub-maximal ratings of perceived exertion elicited during a graded exercise test in obese women.

The purpose was to assess the validity of predicting peak oxygen uptake (.VO(2)peak) from Ratings of Perceived Exertion (RPE)< or =15, during a graded exercise test (GXT), in obese women. Forty-three obese women performed GXT to volitional exhaustion. During GXT, oxygen uptake (.VO(2)) and RPE were measured. Individual linear regressions between .VO(2) and RPE< or =15 were extrapolated to RPE 20 in order to predict .VO(2)peak. Actual and predicted .VO(2)peak were not significantly different (13.9+/-3.0 vs 14.2+/-3.3 ml kg(-1) min(-1), respectively; p=.26). The Pearson product moment correlation between actual and predicted .VO(2)peak was high (r=0.82). The 95% limits of agreement analysis on these values (bias+/-1.96SD) was -0.3+/-3.7 ml kg(-1) min(-1). Results suggested that RPE< or =15 elicited during a sub-maximal GXT provides accurate .VO(2)peak prediction. Therefore, it is not necessary to perform GXT to voluntary exhaustion to determine .VO(2)peak in obese women.

Influence of successive bouts of fatiguing exercise on perceptual and physiological markers during an incremental exercise test.

The purpose of this study was to examine the effects of a succession of fatiguing stages, on ratings of perceived exertion (RPE) and estimated time limits (ETL) during an incremental exercise test. Twenty-seven cyclists performed a continuous incremental test and a discontinuous test with randomized workloads. A linear mixed model was used to compare the RPE, ETL, respiratory gas, heart rate, and blood data obtained during the two exercise tests. RPE and ETL were not significantly different between the tests. Ventilation, breathing frequency, heart rate, and blood lactate concentration were significantly higher during the last incremental test workloads. In conclusion, although the incremental exercise test generated higher cardiorespiratory and muscular workloads than observed during the randomized exercise test, most likely due to a greater fatiguing process, these higher workloads did not influence the perceptual response.

Intermittent versus continuous exercise: effects of perceptually lower exercise in obese women.

INTRODUCTION: Exercise has beneficial effects on obesity and diabetes treatments. However, obese subjects do not closely adhere to training programs probably because of the monotony of the continuous exercise that is frequently proposed. To increase adherence to training programs, intermittent exercise, which is less monotonous, may be more appropriate. PURPOSE: The purposes of this study were to determine the perceptually less hard exercise (continuous vs intermittent exercise) and to analyze the impact of a training program on the basis of this exercise in obese women with and without type 2 diabetes. METHODS: Twenty type 2 diabetic obese women and 20 obese women without diabetes were recruited. In each group, 10 patients integrated a training program (i.e., training groups), whereas the remaining patients were untrained (i.e., control groups). The training groups performed a continuous exercise and an intermittent exercise to determine the perceptually less hard exercise thanks to lower ratings of perceived exertion (RPE). Then, a training program that included 32 min (3 d x wk(-1) x 10 wk(-1)) of the perceptually less hard exercise was proposed to training groups. RESULTS: RPE were significantly lower during the intermittent exercise compared to the continuous exercise in the obese women with or without diabetes (RPE = 12.3 +/- 2.3 vs 13.7 +/- 2.3 and RPE = 11.9 +/- 1.1 vs 13.2 +/- 1.6, respectively). After the training program, significant beneficial effects on the glycosylated hemoglobin (6.8 +/- 1.4% vs 6.5 +/- 1.2%), body mass (97.1 +/- 16.9 vs 95.2 +/- 16.2 kg), body mass index (37.6 +/- 6.1 vs 36.8 +/- 6.0 kg x m(-2)), and on the HR and the walked distance limit were noticed in the training groups. CONCLUSION: The obese women with or without diabetes perceived the intermittent exercise as being less hard than the continuous exercise, and a training program based on intermittent exercises produced beneficial effects on obesity and type 2 diabetes.