Sleds use up all the muscle glycogen in the big muscles in the legs. When muscle glycogen is depleted and carbohydrate is low fats will be burned and the glycerol back bone of the fats will replenish muscle glycogen.
If you’re not used to using fat as fuel, your muscle might feel weaker and burn more some days. That’s a sign that your body needs to adapt.
It will.
Made with Bullet