De la relación entre HPG con NPA positivos a Paramphistómidos

Since the adoption of Title IX over 30 years ago, the number of women participating in athletic activities has more than quadrupled.125 The number of injuries in female athletes has also significantly increased. Athletic activities injuries seem to be concentrated in the knee joint for women. Injuries from athletic activities tend to be more evenly spread throughout the body for men.27 The difference in the rate of occurrence of injuries among men and women varies among activities. For turning, jumping and twisting activities that occur in basketball and soccer, females are between two and ten times more likely to injure their knee, specifically non-contact ACL injuries, than their male counterparts.4,28,46,51,52,66,74,88,97,116,121 There remain differences of opinion as to the reasons for the discrepancies between the ACL injury rates for females and males.46,88,121 Some researchers believe that physiological or anatomical differences, i.e., intrinsic factors, between the genders account for the

discrepancy in injury rates.33,46,66 Others believe that extrinsic factors such as conditioning, skill or experience level account for the difference in injury rates.74,121 Extrinsic factors, such as conditioning or age are less gender specific and are easier to control than intrinsic

factors.66,121 Studies have shown that the baseline level of conditioning is significantly higher for men than women.24,122 Like the general injury mechanism of the ACL, it is most

likely a combination of the intrinsic and extrinsic factors that increase the risk of ACL injuries for female athletes.121

One physiological difference that is believed to have an effect on the stability of the ligaments in females is the cyclic changes in hormones.33,46 Anatomical differences include the structure of the pelvis, and lower extremity alignment, specifically the Q-angle of the hip joints, and the intercodyle notch at the knee joint.33,46,73,74,115 Women have wider hips which can cause higher compressive strain on the medial side of the knee.33,46,66,74,115,116,121,122 This compressive strain is due in part to the angle of the femur from the hip to the knee. The Q- angle, which is formed by the intersection of a line from the center of the patella to the tibial tuberical and a line to the anterior superior iliac spine from the center of the patella, is a way to measure the angle of the femur from the hip to the knee.77 A normal range of a Q-angle for women is 14 to 20 degrees, and for men a normal Q-angle range is 11 to 17 degrees. A higher Q-angle can cause knee subluxation, increase valgus and abduction especially during a sidestep cutting maneuver.73,74,115

Women also have a narrower intercondylar notches than their male

counterparts.46,73,74,115,121 The intercondylar notch lies between the two condyles of the femur. A narrower notch means more limited space for the movement of the ACL, which can cause pinching or stretching as the knee bends. This, in turn, increases the risk of injury due to wear.

Significant gender kinematic and kinetic differenceshave been found at the hip, knee and ankle joints for a sidestep cutting maneuver.88 When performing a sidestep cutting

maneuver, females use the GRFs to control the direction of the movement rather than being prepared to perform the movement and using the muscles to control the direction of

movement.33,51 This lack of neuromuscular control, due to weak muscles,causes a high amount of force to be placed on the knee ligaments by being unable to keep the leg from rotating internally.33,51,98 Compared to their male counterparts, females have been shown to have increased hip joint flexion and adduction, greater valgus and internal rotation and/or decreased flexion at the knee joint and at the ankle joint. 66,70,72,73,121 Women have been found to have increased dorsiflexion and rear foot pronation compared to men.50,68,73,74,88,121 Studies have found that peak knee flexion is less for females than males during sidestep cutting maneuver. 60 Peak flexion that does occur in females during a sidestep cutting maneuver is much later in the stance phase than for males, increasing the possible risk of ACL tears in females.28,46,50,66,74 Females have also been shown to have more quadriceps muscle activation along with generally decreased muscle activation than their male counterparts.46,50,51,66 The greater muscle activation for men, especially a more even activation of the quadriceps and hamstring muscles, confirms the theory that men use the muscles surrounding the knee joint to better protect the ligaments than women do.115,116,121 Combining all the factors, intrinsic and extrinsic, there seems to be more than one factor that increases the risk of a knee injury for both genders, with some of those same factors increasing the specific risk of an ACL injury and increasing the risk of injury even more for women compared to men, for example, a discrepancy between quadriceps and hamstring muscle activation or degree of knee flexion. Having discussed the factors for injury mechanism of the sidestep cutting maneuver, the methods need to be established to find where these mechanisms occur during the cutting maneuver.

2.5 Analysis Methods of Biomechanics