At our Level 1 Training, they discuss this concept as a primary focus for keeping your athletes safe and building them up appropriately.
From the guide:
Mechanics—Does the athlete know the points of performance of the movements? Can the athlete display these points of performance in all movements?
Consistency—Can the athlete perform multiple repetitions of movements well without instruction? Also, has he or she been in the gym long enough to develop a tolerance for intensity?
Intensity—Once an athlete consistently displays sound mechanics and acquires a suitable training history, coaches can introduce intensity with appropriate loads and speeds. (*1)
In the past, we have written about how Intensity tarnishes the CrossFit name...that it is all we seek.
Although it is an invaluable tool, the "Secret Sauce" even, to burning calories and getting results, if approached incorrectly you are going to risk injury and eventually hit a ceiling.
Today this is about how you should approach your workouts, regardless of your experience level!
Each movement has it's standard(s) or "points of performance".
This is what the coach covers, at a minimum, when explaining the workout. There are way more bullet-points we could explain, but we try to stick with the basics and touch on the smaller items as we correct each athlete.
The simplest way to summarize this entire post: if you can not do the movement with proper mechanics, you should not be adding intensity (which can be in the form of speed, weight, or complexity).
This is why we have everyone begin with onboarding and our Active program. We are trying to expose you to core foundational movements we utilize most often, which will later transfer to more complicated movements.
Use the "stairs" info-graphic above as a simple reminder - once mechanics are solid at a certain speed and weight, you can ascend.
If (or more so when) form begins to falter, pull it back a step to stay safe.
Example #1: Push-ups. Whether handstand or regular, it is very easy to see an un-engaged core. Pull it back when this happens.
Handstand to box. Box to regular. Regular to knees.
Example #2: Squats. If you can not squat to parallel, with your knees tracking toes, with your chest up, you should be modifying to accommodate. Squat to box to limit range of motion. Squat in front of a wall to keep chest up. Not to mention many of the other mobility issues to work on outside of squatting.
Trying to only go as hard as you can, will certainly have a negative side-effect.
Do you want longevity or an irrelevant faster time/higher score?