## 1 Introduction  
The force that a muscle group can generate can indicate an athlete's physical condition and, in turn, serves as a criterion for returning to competition after an injury. The quadriceps and hamstring muscle strength provide information about the athlete's function [1]. High levels of strength in the knee flexor/extensor musculature may prevent lower limb injuriesin the athlete population, specifically anterior cruciate ligament (ACL) injuries [2], since the strength relationship between the quadriceps and the hamstring musculature is considered a relevant factor in knee stability [3; 4; 5]. It is important to highlight that the assessment of knee strength is critical in both sports medicine and rehabilitation settings, where accurate measurements of muscle function are essential to evaluate the effectiveness of interventions and prevent injuries. Therefore, alterations in this musculature may increase the risk of lower limb injuries [1]. It is estimated that among the sports population there is one ACL injury for every 3500 athletes. The sports with the highest incidence of ACL injury are basketball and soccer. Additionally, in men's sports, there are a greater number of cases of ACL injuries due to direct trauma, unlike in women's sports, where a greater number of non-contact ACL injuries occur [6]. Notably, ACL injuries (by direct or indirect mechanisms) occur three to six times more frequently in female athletes than in male athletes [7]. One study even reported an incidence up to ten times higher in female athletes [8]. The dynamometer is considered the gold standard tool for measuring muscle strength [2]. This device analyzes the athlete's performance and evaluates medical or physiotherapy interventions and/or injury processes [8]. Different options are used to assess the strength ratio of the knee flexor/extensor musculature. The most common is the conventional hamstring/quadriceps (H/Q) ratio [3]. The conventional ratio is between 0.52 and 0.67 and positively correlates with the test's angular velocity. There is also the functional ratio, which has values around 0.79 at low speeds (60\({}^{\circ}\)/s) and can exceed the value of 1.00 at high speeds (240\({}^{\circ}\)/s) [9]. While a conventional H/Q ratio of less than 0.47 indicates an imbalance of strength and, therefore, an increased risk of lower limb injury [10], there is no consensus on the H/Q ratio at which point the risk of injury increases [4]. While previous studies have explored the relationship between muscle strength and injury risk, little attention has been given to the impact of measurement protocols, such as the positioning of the dynamometer pads, on the accuracy of these assessments. The measurement protocol for obtaining hamstring and quadricep strength values is established in angular velocities between 30\({}^{\circ}\)/s and 360\({}^{\circ}\)/s, with the patient in a seated position with the hip flexion between 80\({}^{\circ}\) and 100\({}^{\circ}\)[11]. The knee's range of motion goes from full extension (0\({}^{\circ}\)) to 90\({}^{\circ}\) flexion [2; 10; 12]. The axis of the dynamometer should always be aligned with the axis of the motion of the knee joint (i.e., external femoral conudyle) [2; 12; 13]. It has been reported that a misalignment, with a difference of 6 to 12 cm between the two structures, causes muscle strength alterations of up to 14% [14]. Fixation straps are placed on the trunk, hip, and thigh to attenuate compensatory movements with the body [2; 4]. The placement of straps increases the fixed points for generating muscle strength, with increases of 5.84% in the knee flexor strength and 1.59% in the extensor strength [15]. Some authors seem to agree on the placement of the distal tibial fixation (pad against which the subject will perform the force) between 2 and 3 cm above the malleulous [2; 4; 12]. However, it has been found that lower strength values are obtained with a more proximal pad, with 24 cm of lever arm from the lateral conudyle [15].