Form and economy whilst racing could be the single greatest predictor of performance success.
Good form maintains muscle integrity. When the brain determines that the skeletal muscle is at risk of severe damage, it will deactivate that muscle and your ability to use that muscle will be lost. But sadly, unlike fuelling and pacing mistakes, muscle damage is irreversible on race day.
Once significant muscle damage has occurred, there are only two options: quit, or continue and invariably incur further damage, and generally have a miserable time. But one thing is certain: you will slow down, and considerably. There is no arguing with neurological deactivation of muscle. It happens for your own protection.
The only way to avoid muscle-related shutdown is self-preservation!