It was unreal, we all rode our bikes instead of walking because my fingers swell so badly during and after a walk. When we rode the 10km track, the way that we usually walk, with no problems, we found our hamstring muscles were aching like F^%& after the ride. Conclusion... walking fast every day does not use certain muscles that are otherwise employed during riding a bike! Amen to that. But, I do FEEL GOOD!!!