To succeed with fitness training
Progression and variation are the key to sustainable fitness training. Going out hard and just increasing doesn't work. It leads infallibly to damage. Heads, muscles and tendons are damaged by hard and one-sided exercise. But by gradually increasing the exercise dose and varying the training, the body keeps the whole season.
There are many opportunities for cardio training at Friskis. Here you have some goodies you don't want to miss.