What type of Cardio
When training for sports. You have to consider what type of Cardio training is required.
For Instance, training for a 10km run requires completely different training than compared if you were training for a boxing match or training for a 100m sprint. There are different energy systems involved.
ATP-PCr / PHOSPHGEN system [Anaerobic Alactic]
GLYCOLYTIC (glycolysis) / LACTIC ACID system [Anaerobic lactic]
OXIDATIVE system [Aerobic]