How do I stop athletes 'Gaming' the start

As far as start options are concerned, having athletes 'game' the system is always an issue.

The absolute best solution, hands down, is to use Steady start in your drills.
Put the G4 gate on the floor. (Do you have the Ground start kit?)
When you use this test, and set "Reaction time" t on in the settings, the athlete cannot anticipate the 2 second delay that steady start implements. Why? Because it will be between 2 and 2.5 seconds.

Remember that because you start with the beam on the front foot, the athlete gets to take one full step, into your test distance before timing actually starts (when front foot lifts).

This is certainly more accurate, more repeatable, and less prone to gaming BUT, on say a 20 yard sprint, the athlete will have stepped 1 yard into that distance before the start occurs. So The results will be faster than a conventional start.

This is not an issue if you ALWAYS implement this , as you are generally looking for CHANGES in performance