The lift requires the lifting of the barbell
from the platform until the athlete reaches an upright position. In the first phase of the movement, the lifter bends his/her ankles, knees, and hips. During the competition, the balance is held with the arms straight and raised until the athlete assumes an upright position and the referee does not indicate to proceed with the phase of support of the load. The first muscles to be involved in this movement are the rear extensors of the lower limb . There are two variants of ground clearance: the conventional and sumo styles. In the first, the barbell is held with the hands placed outside the knees, while in the sumo style, the athlete takes a wider and externally rotated stance and the barbell is held with the hands placed inside the knees [6, 7].
The coaches and athletic trainers specialized in this discipline are very interested in the prevention of the risk of injury. Since all three exercises in this sport trigger multiple joints and are subject to high loads, often several times a week, it has been suggested that the risk of injury could be linked to the use of excessively heavy loads, repeated stress without adequate recovery between sessions and/ or a suboptimal lifting technique . In the review by Bengtsson et al. 41 studies are examined, focusing on the relationship between weightlifting injuries and the three exercises included in powerlifting.
In the bench press, weightlifting injuries were reported to the pectoralis major muscle, fractures of the clavicle, ribs, and dislocations of the glenohumeral joint, as well as various tendinopathies. In relation to the deadlift, however, among the most common lesions were muscle tears in the various muscles of the thigh, lumbar lesions and weightlifting injuries to menisci. In addition, the authors have reported this exercise could be related to episodes of spondylolysis, i.e. an alteration of the morphology of the lumbar spine that consists of the interruption of continuity of the vertebral isthmus, avulsions of the ischial apophysis and damage of the thoracolumbar and dorsal vertebral ligaments .
Only 3 of the 38 studies analyzed in the review reported non-optimal lifting as the cause of the weightlifting injuries. Finally, the squat, often considered a safe exercise as long as it is performed correctly, has often caused disagreement between researchers, coaches, and athletes on what the correct technique of execution should be, in terms of depth of descent, the width of legs, speed of movement, balance position and direction of gaze. With regard to compression forces, it has been shown that they increase with increasing knee flexion.
In addition, stress on the structures close to the knee joint varies when squatting with knee flexion, hip augmentation and internal rotation of the femur (valgus stress). In addition, attention is paid to the depth of the squat, as a deeper squat causes an increase in the load on the hip and knee joints. Injuries reported in connection with squatting include weightlifting injuries to the quadriceps tendon, lacerations of the anterior cruciate ligament, and tears of the biceps femoris musculature.