# Comparative Analysis of Performance in the High-Bar vs. Low-Bar Squat
## 1 Introduction  
Coaches design resistance training programs to develop muscular strength and increase movement velocity [1]. The prescription of appropriate training loads is critical to constructing training plans, and training intensity or volume are the main variables manipulated [2]. Exercise intensity is one of the most important stimuli related to changes in strength levels [3], identified commonly with relative load (percentage of one-repetition maximum--1 RM). 1 RM is a fundamental metric in strength training, as it represents the maximum load an individual can lift in a single repetition. This indicator assesses the maximum strength and the ability to generate force in a specific movement. The 1 RM not only allows for performance comparison between different individuals but is also essential for designing personalized and progressive training programs [4]. However, classical protocolsto assess 1 RM could have potential disadvantages worth noting (associated with injury when performed by novice subjects with poor technique or impracticality for large groups of athletes). An alternative is to use movement velocity. The load-velocity relationship has gained relevance because coaches can evaluate an athlete's strength without the need to perform a 1 RM, because it is possible to estimate it through submaximal loads [5]. In this case, it is common to measure the mean propulsive velocity during the concentric phase of the lift until the bar's acceleration falls below that of gravity. This indicator is important because it reflects the athlete's ability to maintain a constant and efficient velocity during the lift, which is crucial for technique and performance [6]. With the same technology used to [7; 8; 9; 10] evaluate velocity during this type of protocol (i.e., linear position transducer), the force can be assessed during different exercises. In that sense, the force-velocity profile has gained popularity and is used to guide programming decisions. The squat is one of the most widely used exercises in different sports settings, such as fitness, rehabilitation, and strength-power exercise in different sports [11]. The squat is known as a closed kinetic chain exercise consisting of shouldering the bar and performing synergistic hip and knee flexion on the descent phase to the desired depth, followed by knee and hip extension during the ascent phase which ends with the lifter in the starting position [12]. According to [PERSON] [11], more than 200 muscles are activated while executing a squat. Moreover, the most relevant muscles implicated are the knee extensors, erector spinae, gluteus maximus, biceps femoris, rectus femoris, vastus lateralis, vastus medialis muscles, and triceps surae [13]. As a result, it forms an important part of strength training for many athletes. Training studies have assessed the effects of various barbell squat loading schemes on training adaptations, including changes in maximal strength and power in the squat. Additionally, adaptations from squat training and their effects on performance parameters such as countermovement jump height, peak acceleration, and running speed have also been documented [14]. The squat exercise can be varied based on stance width [7], alternating foot rotation, or the surface on which it is performed [15]. The depth of the descent phase also determines different variations, varying between the partial squat or quarter squat (knee flexion angle is between 60-90\({}^{\circ}\)), half squat (knee flexion angle is \(\sim\)90\({}^{\circ}\)), parallel (the longitudinal axis of the thigh is parallel to the ground and the knee flexion angle is \(\sim\)110\({}^{\circ}\)) and deep squat or full squat (the knee flexion angle is \(>\)120\({}^{\circ}\)) [16; 17; 18; 19]. Other variations would affect the position of the bar: the Front Squat (the bar is placed on top of the pectorals lifting parallel to the clavicles) [20], the Overhead Squat (the bar is overhead with the shoulders fully extended) [21] and the Back Squat [15].