Strength training is a process which heavily relies on precision. The amount of exercises are - for various reasons - rather limited. The details they shall be expressed with, however, are not.
A heavy set of five in the squat lasts for about 25 seconds. This is not a great deal of time - but this time requires a great deal of concentration, courage, as well as the readiness to test our physical and mental limits.
It is easy to get complacent on all aspects of our lifts. A little less tension than required while unracking the bar; a rather tame in-breath when starting the Press; a sloppy back tension that doesn't produce the readiness it needs for a successful deadlift. The list is endless, and it doesn't serve our purpose of getting stronger in any shape or form.
The closer every rep looks to what we call "perfection", the faster and more substantial our progress is.
This starts right with the first warm-up set. The weight will feel light - which makes it tempting to let certain parts of the body loose and lift the weight with a technique that does the bare minimum of just getting the job done.
It is from my experience that the more often we execute movements with proficient form, the more the latter is resistant to "noise" during work sets.
Allow me to explain: the more often you practice a lift - regardless of weight - with the required focus and your "ideal" form, the more automated the movement becomes, the less likely it is to be shaken when the going gets tough.
In a "panic" situation like the final rep of a heavy bench press, the body cares about nothing else than getting the job done to prevent being crushed. In short: function appears at the expsense of form.
In a situation like the above, the lifter would be tempted to lift his hips off the bench to improve leverage and "cheat" the bar back into the rack. This, on one hand, would do what his body would require him to do: to get the job done and provide survival. It doesn't have to look pretty. It just needs to work.
On the other hand, this kind of faulty form could lead to potential injury and is certainly not the reason why we are strength training in the first place.
When the lifter executes proper form by using ARM DRIVE in all of his warm-up sets, he is much more likely to default to this CORRECT pattern when things start to feel heavy in the work sets. He would not just prevent potential injury, but also perform the movement in a more efficient and thus stronger way. After all, that's what we care about, don't we?
Being consistent with our set-up and form right from the start is one the most important ingredients for strength progress.
Take your time for setting up each lift correctly.
Revise the steps in your head and on the bar if neccessary.
Breathe in with purpose, get tight, and focus on the right movement mechanics.
Treat every rep with the care and attention it deserves.
Let the power of habit work FOR you, instead of against you.