Prediction Equations Do Not Accurately Estimate Residual Volume And Functional Residual Capacity In Young Athletes

Prediction equations for residual volume (RV) and functional residual capacity (FRC) in athletes are thought to lead to over prediction compared to measurement. PURPOSE: The purpose of this study was to determine if prediction equations accurately estimate RV and FRC in a young athletic population when compared to measured values. METHODS: 35 young high school athletes (age=15.5+1.2; height=174.6+7.3cm; weight=71.8+11.6Kg) were recruited from local athletic teams. Each subject had RV and FRC measured by oxygen dilution technique (Wilmore, 1969) and compared to the prediction equations of Knudson, et. al. (1983). RESULTS: Data were analyzed by independent T-test and revealed that predicted RV was significantly lower than measured RV (mean 1.11+0.102 vs 1.376+0.322; respectively; p< 0.05). Predicted FRC also was different from measured FRC, however predicted FRC over predicted measured FRC as hypothesized (mean 3.236+0.361 vs 2.943+0.668; respectively; p< 0.05). CONCLUSIONS: Data show that the use of prediction equations may not be acceptable for estimation of RV and FRC in young athletes and the premise that FRC is significantly lower in an athletic population may be supported. Further research is required to determine if a change in chest mechanics occurs that influences FRC and RV in athletes or possibly if the type of exercise influences these volumes.