The Research Of Feasibility On Maximal Oxygen Uptake (VO₂max) Measuring By Constant-load Exercise

Objective: Through researching the value of VO₂max which measured by incremental-load, 100% and 110%vVO₂max constant-load exercise, in order to offer the feasibility of using constant-load exercise to measure VO₂max in laboratory. To observe the relationship between VO₂max, VO₂max Pleteau Duration, the lasting time of vVO₂max (tlimvVO₂max) and the time to exhaustion (Tlim) of male students of physical education, supply more selective measuring methods for popularizing scientific exercise.Materials and Methods: Collecting 195 VO₂max protocols measured by incremental-load exercise of male students from Wuhan Institute of Physical Education ( age: 21.87±2.20y,height:173±3.50cm,weight:64.6±4.06kg ), take the velocity which reached VO₂max when measured by incremental-load exercise as 100%vVO₂max constant-load exercise. The average value of 100%vVO₂max is 16.32±1.12km·h-1. One of 15 participated in other two tests which exercised at 100% and 110%vVO₂max constant-load exercise as long as possible until they were totally exhausted. Take the value below 5% of VO₂max as the plateau value, the time of the plateau value is defined as VO₂maxPD. The time to exhaustion (Tlim) at three tests were measured by a stopwatch. We analyzed all results by 15s and 30s respectively(The expired air were averaged by every 15s or 30s). All protocols were dealt by SPSS 13.0.Results:1. The value of VO₂max measured by incremental-load exercise, 100%vVO₂max and 110%vVO₂max constant-load exercise are 3434±359ml/min, 3554±349ml/min, 3660±428ml/min, respectively. There is no great significant difference between incremental-load exercise and constant-load exercise(P > 0.05).2. There is a great significant difference of Tlim among incremental-load exercise, 100%vVO₂max and 110%vVO₂max constant-load exercise(P﹤0.01). The value are 596.87±61.48s, 214.0±77.65s, 144.6±53.12s, respectively. The Tlim of constant-load exercise is longer than incremental-load exercise.3. There is a great significant difference of tlimvVO₂max among incremental-load exercise, 100% vVO₂max and 110%vVO₂max constant-load exercis(eP﹤0.01). The value are 93.87±44.63s, 208.07±54.65s, 144.73±52.90s, respectively. And the tlimvVO₂max of constant-load exercise is much shorter.4. There is no great significant difference of VO₂maxPD among incremental-load ex- ercise, 100%vVO₂max and 110%vVO₂max constant-load exercise(P > 0.05), and the value are 71±35.62s, 67±32.50s, 56±30.78s, respectively.Conclusions: 1. There is no great difference of VO₂max between constant-load exercise and incremental-load exercise, indicate that we can take constant-load exercise as a laboratory way to measure VO₂max.2. It can reach one's VO₂max in2-7min, at least 2min, when measured VO₂max by constant-load exercise.3. When we measured VO₂max by constant-load exercise in laboratory, it's more fitting to take 100%vVO₂max as the intensity of constant-load exercise than 110% vVO₂max.