[1.16.5] Stop Players Sprinting

I'm new to modding but have intermediate Java experience. I'm modifying Mr. Crayfish's gun mod and trying to prevent the player from sprinting while they aim down sights. I've tried doing this in a client side tick, a player tick, and a server tick, and it hasn't worked in any of them. I appreciate your time beforehand.

It was a really basic script, set up properly, just:

if(player.isAiming && player.isSprinting){

player.setSprint(false)

}