[Development of computer software in ramp slope controller for treadmill ergometer]

We developed computer software to produce a treadmill ramp protocol through which oxygen uptake (VO2) is increased in a linear fashion, thus enabling subjects to walk until the end of exercise. The developed software simulates the increases in speed and grade of the treadmill displayed on a personal computer screen, and produces the ramp protocol by arbitrarily determining the variables of the following formula: 1) Increments of VO2 = a1t+a2 (ml/min/kg) [t = exercise time (min)] 2) Predicted VO2 by speed (S) and grade (G) = a3S2 + a4G2 + a5SG + a6S + a7G + a8 (ml/min/kg) [S = speed (km/hr); G = grade (%)] 3) Speed suitable for desired exercise time (S or S2) = a9t2 + a10t + a11 (km/hr) 4) Grade suitable for desired exercise time (G or G2) = a12t2 + a13t + a14 (%) In this study, the increment of VO2 was determined by considering the subject's exercise capacity (VO2 = 4t + 7 ml/min/kg), using the Ito's formula (VO2 = 0.067S2 + 0.289SG + 7.73 ml/min/kg). The formula of grade was determined following the formula arbitrarily (G2 = 25t + 5%). The formula of speed for exercise time was calculated automatically. The new ramp protocol, which was applied to 10 healthy subjects (mean age: 24.8 +/- 4.8 years old), disclosed a similar linear relationship between the predicted VO2 and the measured VO2.