They produce more heat, consume more calories, and receive more blood flow than any of the body's other muscles. Until now, skeletal muscles have largely been ignored. And to top it off , the benefits of weightlifting in general have taken a back seat to such activities as running and aerobics. A super-slow workout offers a variety of rewards, according to Hutchins. For one, slower is safer.
Most weightlifting injuries are the result of poor form and jerky, erratic movements.
Also, the slower you go, the more time the muscles are carrying the weight load. Moving fast can cause momentum to take over and reduce the weight load. You need to master the technique. Concentration on form is important with super-slow. Find a quiet place where you can work uninterrupted for 20-30 minutes.