title: Indirect estimation of VO2max in athletes by ACSM's equation: valid or not?
abstract: OBJECTIVE
  The purpose of this study was to assess the indirect calculation of VO2max using ACSM's equation for Bruce protocol in athletes of different sports and to compare with the directly measured; secondly to develop regression models predicting VO2 max in athletes.
  
  
  METHODS
  Fifty five male athletes of national and international level (mean age 28.3 ± 5.6 yrs) performed graded exercise test with direct measurement of VO2 through ergospirometric device. Moreover, 3 equations were used for the indirect calculation of VO2max: a) VO2max= (0.2 · Speed) + (0.9 · Speed · Grade) + 3.5 (ACSM running equation), b) regression analysis model using enter method and c) stepwise method based on the measured data of VO2. Age, BMI, speed, grade and exercise time were used as independent variables.
  
  
  RESULTS
  Regression analysis using enter method yielded the equation (R=.64, standard error of estimation [SEE] = 6.11): VO2max (ml·kg(-1)·min(-1)) = 58.443 - (0.215 · age) - (0.632 · BMI) - (68.639 · grade) + (1.579 · time) while stepwise method (R = .61, SEE = 6.18) led to: VO2max (ml·kg(-1)·min(-1)) = 33.971 - (0.291 · age) + (1.481 · time). The calculated values of VO2max from these regression models did not differ significantly from the measured VO2max (p>.05). On the contrary, VO2max calculated from the ACSM's running equation was significantly higher from the actually measured value by 14.6% (p <.05).
  
  
  CONCLUSIONS
  In conclusion, it seems that ACSM's equation is not capable of accurately predicting VO2max in athletes aged 18-37 years using Bruce protocol. Only the regression models were correlated moderately with the actually measured values of VO2max.
authors.affiliation: Sports Medicine Laboratory.
authors.forename: N
authors.initials: N
authors.lastname: Koutlianos
authors.affiliation: Sports Medicine Laboratory.
authors.forename: E
authors.initials: E
authors.lastname: Dimitros
authors.affiliation: Laboratory of Ergophysiology-Ergometry, Department of Physical Education & Sport Science, Aristotle University of Thessaloniki, Thermi, Greece.
authors.forename: T
authors.initials: T
authors.lastname: Metaxas
authors.affiliation: Sports Medicine Laboratory.
authors.forename: M
authors.initials: M
authors.lastname: Cansiz
authors.affiliation: Sports Medicine Laboratory.
authors.forename: As
authors.initials: A
authors.lastname: Deligiannis
authors.affiliation: Sports Medicine Laboratory.
authors.forename: E
authors.initials: E
authors.lastname: Kouidi
keywords: VO2max prediction; cardiorespiratory fitness; exercise testing; metabolic equivalent; running equation