Lifting Weight Fast or Slow?

Lifting weights slowly is good for beginners who need to learn and master the movements to prevent bad form. Once you have mastered the moves you should lift as quickly as possible without sacrificing form and without a jerking movement.

By lifting fast you create more force and therefore more muscle fibres need to be activated. If you lift the weights super slow you accumulate too much lactic acid within your muscle and it fatigues them. If you can remember back to your school days we learned that 

Force = Mass x Acceleration