A HealthRider is one of those home exercise machine thingies for people who are starting to get fit. You sit on the seat, put your feet on pegs and your hands on handlebars, and use your arms and legs together to raise your seat. When you raise the seat, your legs and hips straighten out. Up, down, up, down... someone using it looks like someone practicing to have sex. :-)

Confusingly enough, HealthRider went on to make treadmills and stationary bicycles, so the name "HealthRider" doesn't strictly describe only this object.

This link has a description meant to sell the thing.

Thanks for asking sinboy! I am sure we can work something out.