Take these self-tests to find out
Pop quiz: Which is worse, having a muscle weakness on both sides of your body–or on just one side? It’s the latter, says Gray Cook, P.T., one of the world’s top fitness experts. Click on the video to find out why, and to learn two simple self-tests you can use to identify problem areas. The upshot: Use Cook’s advice to fix your flaws, and you’ll be able to increase your size and strength faster than ever before.