Final answer:
After high-intensity training in stage 3, low-intensity exercise or rest day is recommended for recovery.
Step-by-step explanation:
After a day of high-intensity training in stage 3, low-intensity exercise is ideally recommended to allow the body to recover and reduce the risk of injury. This can include activities such as light jogging, walking, or stretching.
Engaging in moderate-intensity exercise is not recommended as it may further strain the muscles and impede the recovery process.
Rest day is also an important option to consider, as it allows the body to fully recover and recharge for future training sessions.