For instance, a lifter may have his or her lumbar flatten and begin to round during the performance of a very heavy deadlift. But the lower back will not be allowed to flex past a certain range of motion. Past this range of motion the lifter would abandon the attempt. This is not cheating. Instead it is the reality of lifting heavy objects.
This excuses my form :-P
It really does boil down to what you've said:
What many people call "cheating" in strength training movements are actually compensations that are a natural part of lifting maximal loads. These compensations are simply natural deviations from "ideal form" and experienced lifters tend to have a educated sense of acceptable and unacceptable deviations.
I know I get critiqued for my DL form but even on Front Squats, I have that rounding thing except I am now able to tell instinctively when it is too much and dumping the weight is a better idea.
Feet Up Benching on a Smith Machine
Worse than Cheating?
Cracked me up
This means that only a few exercises can actually be "cheated" on productively and somewhat safely owing to their strength curve. Basically, for these lifts we are weakest at the bottom and strongest somewhere around the middle. Obvious examples are biceps curls, overhead press, and pullups. In fact, a cheat movement on the strict overhead press has it's own name, the Push Press, and this can be an effective tool. So cheating, again, is not always the right word and the appropriateness of it depends on the intentions and context in which it is used.
This reminds me of your article on Kipping Pull-ups vs. Normal Pull-ups. Similarly, the Push Press and the Overhead Press shouldn't be called the same thing even though neither is "wrong".
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