The only exception was the 150mm ta which came equipped with a 36-tooth ring. We made up for the difference by selecting another cog in the rear. The CompuTrainer Professional Model 8001 used in this experiment consists of a stable training stand connected to a handlebar-mounted computer, a television and a Nintendo machine. The training stand attaches to the ends of the rear axle of the user's bicycle, and the resistance in the roller under the tire is varied via the computer based on inputs given by the user. The CompuTrainer measures power output, speed, distance, pedal cadence and heart rate.
Heart rate is measured through a sensor on a clip attached to the rider's earlobe.
We checked the monitor for accuracy against a Polar Vantage xl and the results were accurate to within one beat per minute. The 1996 CompuTrainer model allows the force at the interface between the roller and the rear tire to be calibrated. This smoothes out some variations in the power-output reading cause by different tires, air pressures, tire temperatures, and torque on the bolt pressing the roller against the tires. In each round, the rider rode on a simulated 4-percent grade. Starting with lowest gear, the rider pedaled at 90 rpm for three minutes.