When you excercise, workout or whatever an acid is produced that basically damages your muscles. When your muscles try to recover from this they become larger from the scar tissue formed by the...
The main question on this topic is where do you want to build muscle? For a core workout the best thing is press ups and sit ups. You can do the same work through different means at the gym or select...
Depends on what kinds of muscles, and Lower or Upper Leg. If you're training for explosive strength, Jogging on the spot while raising your knees as high as possible is a good training exercise....