1: Therapy 2: Physical activity 3: Body 4: Fitness 5: Relaxation 6: Treatment 7: Blood 8: Exercise 9: Injury 10: Endurance 11: Health 12: Strength 13: Weight 14: Movement 15: Training 16: Shoulder 17: Balance 18: Muscle 19: Stretch 20: Effort (As of 13:55)
Anaerobic Threshold refers to the point at which the muscles of the body start to work without oxygen, from an aerobic level.
This threshold is believed to be at approximately 87% of the Maximum Heart Rate.