One former commando says it’s as demanding as his time in the special forces. But even those who have never run before sign ...

Hang from elbow straps or hold yourself up on parallel bars. Cinching in through your abs, draw your knees up toward chest, ...

It’s a good idea to buy a 75- to 100-pound bag (a long, cylindrical bag that can be hung from a stand or a sturdy ceiling beam), boxing gloves, a medicine ball, and a jump rope. These four items ...