Styrofoam isn’t just for packing peanuts . Those long, foam logs you’ve probably noticed laying around at your gym are the ticket to preventing muscle soreness–and potentially sidelining injuries. By simply rolling over sore and stiff spots, like your hamstrings, quads and middle back, you’ll break up muscle knots with your body weight. This improves bloodflow, aids flexibility, and can provide serious relief from aches and pains. Think of the foam roller as a personal masseuse–without the hefty price tag.