Determining the anaerobic threshold in postpolio syndrome: comparison with current guidelines for training intensity prescription.

OBJECTIVES

To determine whether the anaerobic threshold (AT) can be identified in individuals with postpolio syndrome (PPS) using submaximal incremental exercise testing, and to compare current guidelines for intensity prescription in PPS with the AT.

DESIGN

Cohort study.

SETTING

Research laboratory.

PARTICIPANTS

Individuals with PPS (N=82).

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Power output, gas exchange variables, heart rate, and rating of perceived exertion (RPE) were measured in an incremental submaximal cycle ergometry test. Two independent observers identified the AT. Comparison of current guidelines for training intensity prescription in PPS (40%-60% heart rate reserve [HRR] or RPE of 12) with the AT was based on correlations between recommended heart rate and the heart rate at the AT. In addition, we determined the proportion of individuals that would have been recommended to train at an intensity corresponding to their AT.

RESULTS

The AT was identified in 63 (77%) of the participants. Pearson correlation coefficients between the recommended heart rate and the heart rate at the AT were lower in cases of 40% HRR (r=.56) and 60% HRR (r=.50) than in cases of prescription based on the RPE (r=.86). Based on the RPE, 55% of the individuals would have been recommended to train at an intensity corresponding to their AT. This proportion was higher compared with 40% HRR (41%) or 60% HRR (18%) as criterion.

CONCLUSIONS

The AT can be identified in most individuals with PPS offering an individualized target for aerobic training. If the AT cannot be identified (eg, because gas analysis equipment is not available), intensity prescription can best be based on the RPE.