Aerobic power prediction in patients recovering from limb injury

Procedures for the prediction of one-leg and two-leg maximal aerobic power output (VO2 max) have been examined in a group of 15 young men having had fracture of one leg and consequent immobilization resulting in muscle atrophy. Extrapolation of the submaximal cardiac frequency (FH) and oxygen intake (VO2) responses to an assumed FH amx of 175 in one-leg and 195 in two-leg work resulted in a systematic overestimation of VO2 max. This overestimation could be removed by applying the appropriate regression equations, but the overall accuracy of the extrapolation method was limited to +/- 15% in the case of the injured leg and +/- 8% for either the uninjured leg or both legs combined. Prediction of VO2 max from leg muscle (plus bone) volume gave the same order of accuracy. However, it was shown that the VO2 max of the injured leg could be predicted with an accuracy of +/- 5%, if the observed VO2 max data of the uninjured leg and two legs were combined and utilized in the following formula: VO2 max (injured leg) = (A X 2) - VO2 max (uninjured leg), where A is the mean one-leg VO2 max predicted from the two-leg VO2 max observed. It was concluded that wherever possible the one-leg and two-leg VO2 max of patients undergoing rehabilitation therapy should be measured directly. If the patient is unable to pedal the bicycle ergometer with his injured leg alone then the VO2 max of this limb may be predicted from leg volume measurements or from the observed uninjured and two-leg VO2 max with an accuracy of approximately 8%.