https://m.youtube.com/watch?v=UhVXzJKjqaM

So sometimes when people do certain repetetive exercises the key limiting factor is not their muscles strength or endurance but their skin

Skin rubbing against objects having the potential for injury can prevent more repetitions , or effect grip which limits object weight which limits how much strength, speed, flexibility or endurance you develop

This can apply to weightlifting, dynamic stretching, walking ,running and practicing using martial arts tools