It’s recommended to read movement analyze chapter before reading this one.

There are many different opinions between trainers regarding the type and tempo of movement. Some prefer negatives (making only the negative part of the movement) and others static workouts. Some recommend slow movement while others spurt ones.

If our goal is micro injuries[^1] (main component of muscle strength and mass) than type and tempo of movement doesn’t matter. This goal can be achieved by any movement type and tempo. You should remember across training period consumption speed of energy should increase (this is because over training reservoirs of Creatine Phosphate increase and so ATP’s recreation speed). Consumption speed of energy can be increased by increasing working weight or by changing movement technique (for instance: making the negative phase of movement slower).

I’d recommend slow and controlled movement. Execution of the negative phase should be slower than positive one (probably 24 or 23, but slower tempo could also be tried [super slow]). Rationalization: one of the principles in Hippocratic Oath taken by physicians is: never do harm to nobody. Not causing injuries should be your first priority. Other type and tempo of movement are potentially more dangerous.

Other types and tempos have their place, but in generally they should be used by experienced athletes for special purposes.

[^1]For more information see: muscle damage theory.