Effects of a variable-ratio reinforcement schedule with changing criteria on exercise in obese and nonobese boys.

Researchers worked with eight boys, four obese and four non-obese, .

Each child pedaled a stationary bike while earning points on a changing-criterion variable-ratio schedule.

The target revolutions per minute went up by a large share every few days; kids traded points for toys at the end.

Obese boys started slower but reached the same final speed as the non-obese group.

Pedal rates climbed in step with each new criterion; no extra coaching was needed.

The changing-criterion VR schedule kept all kids pushing harder across the four-week study.

Aguirre Mtanous et al. (2026) later showed adults with Down syndrome can also gain fitness, but the increase was small.

Sosnowski et al. (2022) got big gains in the same group using basketball instead of bikes; the sport added social fun.

Iwata et al. (1990) proved even toddlers work faster under ratio schedules, so the schedule itself is solid across ages.

You can use a changing-criterion VR plan whenever you need to build endurance with clients of any age. Set each new target just a large share above the last mean, hand out points or tokens, and let the schedule do the driving. It works for bike riding, rowing, or even jumping jacks.