A mixed model was used to derive the following equation for predicting physical activity energy expenditure (EE):
EE = -59.3954 + gender x (-36.3781 + 0.271 x age + 0.394 x weight + 0.404 V[O.sub.2max] + 0.634x heart rate) + (1 - gender) x (0.274 x age + 0.103x weight + 0.380x V[O.sub.2max] + 0.450 x heart rate)
where gender = 1 for males and 0 for females.