title: Narita target heart rate equation underestimates the predicted adequate exercise level in sedentary young boys.
abstract: OBJECTIVE
  Optimal training intensity and the adequate exercise level for physical fitness is one of the most important interests of coaches and sports physiologists. The aim of this study was to investigate the validity of the Narita et al target heart rate equation for the adequate exercise training level in sedentary young boys.
  
  
  METHODS
  Forty two sedentary young boys (19.07±1.16 years) undertook a blood lactate transition threshold maximal treadmill test to volitional exhaustion with continuous respiratory gas measurements according to the Craig method. The anaerobic threshold (AT) of the participants then was calculated using the Narita target heart rate equation.
  
  
  RESULTS
  Hopkin's spreadsheet to obtain confidence limit and the chance of the true difference between gas measurements and Narita target heart rate equation revealed that the Narita equation most likely underestimates the measured anaerobic threshold in sedentary young boys (168.76±15 vs. 130.08±14.36) (Difference ±90% confidence limit: 38.1±18). Intraclass correlation coefficient (ICC) showed a poor agreement between the criterion method and Narita equation (ICC= 0.03).
  
  
  CONCLUSIONS
  According to the results, the Narita equation underestimates the measured AT. It seems that the Narita equation is a good predictor of aerobic not AT which can be investigated in the future studies.
authors.affiliation: Department of Physical Education & Sport Sciences, University of Mohaghegh Ardabili, Ardabil, Iran.
authors.forename: Marefat
authors.initials: M
authors.lastname: Siahkouhian
authors.affiliation: Department of Physical Education & Sport Sciences, University of Mohaghegh Ardabili, Ardabil, Iran.
authors.forename: Davar
authors.initials: D
authors.lastname: Khodadadi
keywords: Aerobic Threshold; Anaerobic Threshold; Heart Rate Performance Curve (HRPC); Training Intensity