Unlike a normal squat, the heels are elevated, shifting the knees far forward. This places more stress than usual upon the knee joint, both the knee extensors (quadriceps) and the ligaments as well, when highly flexed at the bottom if hyperflexion begins to occur. Due to the increased stress, there is a higher risk of injury to the knee while squatting this way, especially if done ballistically. Some feel that this risk is not worth doing the exercise, others that doing it with control and awareness will overtime strengthen the knee in response to the increased stress to become more resistance to other injury.
Due to the elevated heels, the plantar flexors are recruited more than in regular squats.
Due to the lack of stability in the exercise compared to a normal squat, adding additional weight must be done more conservatively. Barbells are not a good idea, but rather something affixed to the body such as weighted clothing or using a medicine ball. The exercise is more suited to higher repetitions which compensate for the lack of maximum resistance. Even when adding it, one can build up to higher repetitions with a lower weight before switching to a higher one.
- The hands may remain stationary throughout the exercise, or move in tune with the movement
- Breathing may be done normally (exhaling on the concentric) or reversed (inhaling on the concentric). Any negative or positive effects one way or the other are hard to notice due to the lack of resistance, and are more of a cardiovascular consideration.