Some factors affecting accuracy of Canadian Home Fitness Test scores

Factors affecting the accuracy of Canadian Home Fitness Test scores have been evaluated in male and female office workers. At a first attempt, the typical subject underestimates his 10 sec post-exercise pulse count by 1 beat, with a superimposed probable error of 2 beats. However, the modest experience of pulse counting gained in an employee fitness programme corrects the systematic error, while the probable random error is reduced to approximately 8 beats/min. Taking account also of variations in the fficiency of stepping, the probable error of an Astrand prediction of V O2(max) is approximately 10.3%. Comparison with directly measured values in a subsample of 22 men shows an actual random discrepancy of 9.5%, plus a systematic error of approximately 19% due to an increase of heart rate with anticipation of the maximum test. The Jetté prediction formula has a random discrepancy of approximately 8%, plus a systematic error of approximately 10.6%. Assuming the latter can be corrected by evaluation of a larger population, the fitness scores should give most people an indication of both their initial fitness and responses to a training regimen.