Coaches read a heavy legged player as a motivation problem without ever asking what they ate.
A flat session is not always a bad attitude
Somebody is a yard off it on a Tuesday and the coaching response is almost automatic. Louder voice. A comment about standards. Maybe an extra run at the end so the group understands what happens when effort drops. I have watched that exact sequence applied to a nineteen year old who had eaten a bag of crisps since breakfast because he finished college at four and training started at six.
The reason we default to attitude is that attitude is the explanation coaches feel qualified to give. It fits the story of the job, it is satisfying to correct, and it costs nothing to diagnose. Asking about food feels like the nutritionist's territory, and in most clubs the nutritionist is a two hour visit on a Thursday.
So here is the cheap alternative. Ask the question before you make the judgement. What did you eat, when, and how long was the journey. Ten seconds, no lecture, before the group starts. Do it for a fortnight and you will begin to notice that flatness clusters, and it clusters around the same people at the same time of the week, and that time is usually the session that follows a full day of school, work or travel.
Once you can see the pattern the fix is often a scheduling one rather than a nutritional one. Move the evening session fifteen minutes later and put food in the gap. Keep something edible in the building. Tell the group explicitly that arriving unfuelled is not toughness, because plenty of them believe the opposite and some of them learned that belief from a coach.
The part I feel strongly about is the extra running. Punishing a session that was flat for an unaddressed reason teaches the athlete that the honest answer has a cost. Next week they will not tell you they skipped lunch. They will just hide it better, and you will have destroyed the only sensor you had.
None of this means effort never drops. It does, people are people, and there are athletes who need a hard conversation. But you cannot know which one you are looking at until you have eliminated the boring explanation, and the boring explanation is right more often than coaching folklore admits.
Diagnose before you correct. A coach who reads every flat night as character is not reading anything, they are just repeating a reflex.

