improve a person's sense of balance. As with other forms of one legged exercise performed alternately, they can also help to mitigate against an excessive strength variation between the legs, as both legs are made to perform the same level of work e.g. in a two legged squat a person's right leg may do 55% of the work and their left leg 45%, which may result in an excessively uneven level of strength developing. By switching between using the right leg and left leg in one legged squats, a person can better ensure that each leg is doing the same level of work i.e. the right or left leg does 100% of the work for each respective one legged squat. Pistol squat – a bodyweight single leg squat done to full depth, while the other leg is extended off the floor and positioned somewhere in front. Sometimes dumbbells, kettlebells or medicine balls are added for resistance. Pistol squats may be performed with the foot flat on the floor or with the heel raised. Shrimp squat – also called the flamingo squat, a version of the pistols squat where instead of extending the non-working leg out in front, it is bent and placed behind the working leg while squatting, perhaps held behind in a hand. Shrimp squats may be performed with the foot flat on the floor or with the heel raised. Jockey squat - a half-squat, performed by being balanced on the forefeet throughout the repetition, with fingertips touching across the chest. This squat can be performed quickly and in high repetitions. Sissy squat – the knees travel over the toes, stretching the quadriceps and the body leans backwards. Can be done in a special sissy squat machine, and can also be weighted. Sumo Squat - also known as Plie Squat, in this variation legs are wider than shoulder width. Injury considerations Although the squat has long been a basic element of weight training, it has not been without controversy over its safety. Some trainers claim that squats are associated with injuries to the lumbar spine and knees. Others, however, continue to advocate the squat as one of the best exercises for building muscle and strength. Some coaches maintain that incomplete squats (those terminating above parallel) are both less effective and more likely to cause injury than full squat (terminating with hips at or below knee level). A 2013 review