csgo-like crouch stamina, the more you crouch the slower you do so
almost guaranteed to not work with other movement addons because of how common it is for them to use https://wiki.facepunch.com/gmod/Player:SetDuckSpeed.
please go ask for Facepunch/garrysmod-requests#1403 to be resolved if you want this to improve.
sv_crouch_stamina- (0/1)- Sets whether crouch stamina is enabled or not.
sv_crouch_stamina_cooldown- (0 <--> float)- Sets the minimum time players must wait before being allowed to crouch again.
sv_crouch_stamina_spam_penalty- (0 <--> float)- Modifies how much stamina is lost when crouching.
sv_crouch_stamina_slow_movement- (0/1)- Slows movement by using crouch stamina.