Mods like these (sprint bar, sprint hook, and reconnect.cs) are all allowed for the moment. This is because, with these types of mods, there is not a single way that any member of the staff team would be able to spot someone using this - unless we are provided with live streams of every single player's PC, which is of course not going to happen.
To clarify this specific mod a little bit more, what this does is adds an extra bar which is representative of how much stamina is left within a player (similar to how the armour and health bar works). You cannot in any way add more stamina to your player model or increase the duration of how long you can continuously exert yourself. Take it into consideration of a real situation, would knowing how much stamina you have left (with the use of numerical values) stop you running from a fight because you have noticed a low value displayed on the bar? I would assume the answer to be a "no". So, in short, you would only know that you are going to be out of stamina or know how much of it is left in you until the time of exhaustion, there will be no way to prevent it from running out or using this as an advantage in any situation.
I have intended to be as clear as possible, and I hope this clears the doubts with asking the allowance of mods that are similar to this.
