Whenever you walk into a gym, you will see a few people in expensive workout outfits delicately lifting pretty little three- or five-pound dumbbells, often hundreds of times.
The positive side of using very light dumbbells is that you won’t break a sweat or get your pristine workout outfit dirty.
The negative side is that while spending a long time lifting light weights is better than doing nothing at all, it’s not effective.
You don’t actually build muscles when you are lifting weights.
Instead, lifting breaks down muscle fibers, which your body repairs with firmer, stronger ones as you recover from a workout.
Unfortunately, lifting very light weights doesn’t break down muscle fibers, and thus doesn’t lead to the rebuilding process which increases your strength and defines your muscles. Some women worry that if they lift heavy weights they will bulk up like male bodybuilders, but that won’t happen.
The huge muscles you see on Mr. Olympia contestants require two things: testosterone and years of long, extremely intense gym workouts.
For effective and efficient strengthening, which build firm, lean muscles, choose a weight you can lift no more than 15 times and do one set of exercises for each major muscle group in pulling and pushing directions.
http://www.workoutplan.com/8-most-useless-workouts-ever/15/
