Make sure your bench presses are standardized. In practical terms that means paused. And almost nobody pauses, even when they think they are. But if you don't pause your presses will change the heavier they get, and that puts you more at risk for getting injured (worst case) or simply thinking you are stronger than you are (likely case). Also for being standardized, nobody else can touch the bar, not even a finger underneath "just to make sure."
Paused or Touch and Go Reps
Both will increased strength. However, each provide a different training effect.
Paused Reps
Paused Reps dampen or kill the Stretch Reflex. The Stretch Reflex occurs with Touch and Go Benching, the slight bounce off the chest providing a "Sling Shot" effect in driving the weight up.
Research show that up to 18% more power is produce with certain type of Stretch Reflex, Plyometric Actions.
Pausing the weight for 4 second plus, kills the "Stretch Reflex".
Advantages of Paused Reps
Pausing each rep on the chest, the driving it up, increases strength off the chest in the first 1/3 of the movement.
Disadvantages
Paused Benches increase strength off the chest but do not overload the muscle in the remaining 2/3 of the movement.
Paused Benches do not develop the Stretch Reflex, a vital component in the majority of sports.
Touch and Go Benching
This type of Bench trains and develops the Stretch Reflex.
It increased the loading on the top end of the Bench Press; allowing more muscle fiber to to worked. To increase strength and/or size muscle fibers need to be worked.
Injury
No injury will occur from a Touch and Go Bench unless a lifter is preforming it incorrectly.
Bench Training
A good training program will incorporate Paused and Touch and Go Rep Benching.
Kenny Croxdale