The start of nice weather means everything is thawing out. Breaking out the bicycle is a great idea for jumpstarting spring weight loss. Getting around by bike is also a great way to get a head start on celebrating Earth Day by eschewing gas-guzzling cars. Riding your bike for an hour at a steady pace can burn up to 533 calories for a 140-pound individual. Uphill riding is a great cardio workout, and it burns leg fat and builds muscle in the quadriceps and hamstrings in particular. Building those large leg muscles means you'll burn more calories at rest. However, it's important to keep safety precautions in mind when you go for a ride. Most people don't even consider wearing a helmet when they go for a leisurely bike ride. But it can prevent serious injuries.