There's a new park that opened up by my house, and they have work out equipment outside. Such as stair climbers, ellipticals (sp?), manual treadmills, etc. I want to start going there once the weather warms up just a tad. Does anyone know if any of these are safe to work out on? For how long? I'm not planning on doing any of it in the blazing heat. I tried googling info, but I couldn't find anything on it. Thanks!