Use the lifting tempo that lets you lift the heaviest weights with proper form. Lifting slowly is not good because it wastes straight. But lifting too fast makes it harder to control the bar and lift with proper form. You must be in control of the ber at all times.
The first weeks of strong lift 5×5 you will heave to lift more slowly so you can practice proper form. But as you gain experience you can start accelerating the ber on the way up. This recruits more muscle fibers and helps you lift heavier weight.
Always lower the ber under control. Do not lower it slowly because that wastes strength. But do not drop the ber either. Control it on the way down so you can maintain proper form. The ber should go down faster then it moves up. And the ber path should be as close to vertical as possible.
Lifting slow causes more pump and fatigue. But it also limits how heavy you can go. The goal of this programme is to lift heavy. You can lift heavier when you lift first. Thet’s why lifting fast recruits more muscle fibers the heavier weight focus more muscle to get involved to lift it.
Lifting fast does not mean the ber will actually move first. Your lighter warmup weights move fast. Your lighter warmup weights will move first. But your heavy work sets won’t always do. The ber can sometimes move slowly on heard reps aka grinders. The point is that you put all your strength into the ber by training to accelerate it.
Take your time between reps. Rest a second before doing the next rep so you can get tight and take a big breath. This will also give you same recovery. Do not rush your reps or you will lose focus and lift with bad form.