"Momentum"

Is considered a tangible thing during a game.
Being "in rhythm" as an offense as well.

These are invisible psychological descriptions of unit cohesion at a particular point in time.

In a game of inches dealing with hundreds and hundreds of pounds of bodies and applied force per snap, any mental issue is amplified.
If someone is uncomfortable or has extra pressure because they're playing next to a new person, in a new role, they will most likely be playing tight.
If they are, their muscles and tendons are not going to function optimally.

If morale is low because of poor performances they're likely to be up in their head and playing slow.

Tight plus slow in a game of inches equals losses and increases the likelihood of injury.

Teams that are confident and relaxed but with a spring in their step? Much less likely.

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