While there are plenty of bogus valid excuses for skipping out on your workout [1] — I'm busy, I'm too tired, I'm too stressed — those will quickly melt away once you meet Constance Tillett. She's a 76-year old CrossFit athlete, and she knows excuses aren't an option. She's had hip replacements, knee replacements, shoulder replacements, and says, "I'm a diabetic, I have a cardiac problem, and I have arthritis." After her last surgery, she had a moment of realization about what was going on for people her age, and she decided to do something about it. She says, "each day it's a challenge, but you have to think positive. . . I'm not ready to die yet, and I'm trying to keep hope alive."

If you've always wanted to try CrossFit, check out this 10-minute workout video [2] you can do at home.