A disadvantage to Fartlek training is:
A. It can cause injury.
B. It can be boring.
C. Difficulty for coaches and trainers to know if the performer is working as hard as they should be.
D. It trains only the aerobic system.
Explanation: It increases the risk of injury for beginners as they are newer to running and it is not ideal to add faster segments into training until you reach a higher fitness level
