It sucks to drag yourself outside to exercise in the snow -- or here, rain. 0_o It's raining in January. Here are some indoor activities instead. By the way, if you can't afford a trampoline, box jumping is cheaper and also excellent if what you want to improve is control, precision, and finesse rather than just raw power. You can do these on a step, a curb, a bench, or any other low sturdy surface.