# The Use of Free Weight Squats in Sports: A Narrative Review--Terminology and Biomechanics
## 3 Basic Terminology Related to Squating Movements
It has been advised that box squats should only be used to improve low bar squat performance, specifically for those competing in powerlifting [41]. However, more scientific inquiry into the efficacy of box squats is necessary. Another back or front squat derivative, with full, parallel, and partial variants, is the speed squat [50], where the velocity of movement throughout the concentric phase is intentionally maximized to create a ballistic or semi-ballistic high power movement [51; 52; 53]. Speed squats are often timed for a specific number of repetitions and load; the lifter tries to decrease the exercise time with training, thus raising the average power of the movements. Often this squat variant is performed in a manner in which the athlete plantar flexes and rises onto the balls of their feet [47]. Front squat: The front squat is a derivation that is not as frequently used in training as the traditional back squat exercise [52; 54; 55]. However, the importance of the front squat cannot be underestimated because of its relationship to the clean and power clean movements [13; 48], which are commonly part of comprehensive strength and conditioning programs [9; 10; 14; 15; 53]. The front squat exercise is typically performed with a prorated grip with the barbell held across the anterior portion of the deltoids and clavicles [35; 54; 55]. For athletes who lack wrist and shoulder flexibility, the grip can be modified by either using a cross-armed grip [35; 40; 54] or by using lifting straps to help hold the barbell [35]. The load that can be lifted during a front squat is typically less than in a back squat [27; 55]. Jump squat: The jump squat is a derivative of the high bar back squat, as the bar placement is typically centered across the shoulders just below the spinous process of the C7 verteba [56]. However, it is sometimes classified as a different exercise group because of its unique power attributes and the various levels of depth that can be used. Typically, the jump squat is considered a ballistic or explosive exercise, as the object of the exercise is to physically jump into the air while under load, thus removing the braking phase that occurs towards the end of the ascent in traditional squatting exercises [57]. Alternative methods for the performance of the jump squat can include movements with either dumbbells or on a restricted lifting device such as a Smith machine, although task specific adaptations may be different [12; 17]. Jump squats can be performed as a countermovement exercise or from a static start. One-leg squat: The one-leg squat, unilateral squat, fore-aft split squat, or \"Bulgarian\" split squat is performed with one leg designated as the stance leg, while the support leg is often placed at knee height on an adjustable bench located behind the athlete [55; 58]. The stance leg's distance from the bench is adjusted in order to allow the athlete to be able to descend to a position in which the posterior portion of the thigh is parallel to the ground [55; 59] or to where the top of thigh is parallel to the ground [58]. An alternative approach would be to not elevate the support leg, keeping both feet in contact with the floor [60]. One-leg squats can also be performed with the stance leg elevated to the side and the support leg on the ground beside the lifter. Step-ups, although typically viewed as auxiliary exercises, are essentially a type of one-leg squats, where the athlete steps up on an adjustable box or bench to vary hip or knee range of motion (RoM). Regardless of which variant of the one-leg squat is used, a barbell can be held in a high bar position [58], or dumbbells can be held in one or each hand [60]. Interestingly, these types of unilateral squats are not typically considered a primary training exercise, as they are often programmed based on the athlete's maximum back squat strength or in relation to body mass [51; 61]. The maximal lifting capacity using these exercises is substantially less than what can be accomplished in a back or front squat.