Prediction Of Lactate Threshold By Physiological Variables Utilizing Human Motion During Exercise

Abstract

Running at Lactate threshold (LT) for training is a frequent training method used by healthy and elite athletes. However, LT determination is usually done in the laboratory with an invasive method. PURPOSE: To predict LT by physiological variables utilizing human motion during exercise. METHODS: 12 male athletes (Age: 23.6±1.8years, Percentage (%) body fat: 12.4±3.3%, height: 173.4±4.7cm, weight: 68.2±5.8kg, bone mineral content: 2738.6±252g and lean mass: 56233.7±4751.4g) completed an incremental discontinuous submaximal to exhaustion protocol on the treadmill. VO2 ml*kg-1*min-1 was determined at every stage and VO2max ml*kg-1*min-1 was determined at volitional exhaustion. Human motion, blood lactate, heart rate (HR), VO2 and Rate of Perceived Exertion (RPE) were constantly measured. RESULTS: Among the 32 human motions, 8 human motions (4 on left leg and 4 on right leg) demonstrated strong relationship (correlation r > 0.700) to human bioenergetics during running. The range of human motion on left leg (10 % - 70 %) significantly varies than right leg (5 % - 15 %) due the right leg being dominant. Two human motions had the highest correlation with human bioenergetics 1) the angle between left (thigh & leg) phase 1 and 2) (r = 0.908) and angle between right (thigh & leg) phase 3 (r = 0.858). The equations derived with human motions (A) VO2 = (VO2 - 7.56)±10.83ml*kg-1*min-1 and (B) VO2 = (VO2-15.81)±15.76ml*kg-1*min-1 can be used to predict the VO2 at LT if VO2max is known. CONCLUSIONS: Results indicated that human motions have significant relationship with HR, VO2, and blood lactate during running at submaximal intensities. The human motion derived equation can predict VO2 at LT if VO2 at exhaustion is known without using a invasive method.