Biomechanics and neuromuscular control mechanisms during technical athletic gestures in women's basketball and in the prevention of traumatic pathologies of ACL.

In addition to the "opposition to the anterior translation of the tibia, the co-contraction of the hamstring and quadriceps, and of the gastrocnemius, increases the support in defense of the pathological movements in varus - valgus internal and external rotation, which are numerous during a" basketball match both in the defensive phase and in the offensive phase.
When the varus-valgus movements associated with internal-external rotation are performed, they are protected by the simultaneous activation of all the muscular districts of the knee. The co-contraction of the quadriceps and the hamstring increases the stiffness of the joint (understood as coaptation) in all these load directions.
Buchann et al., Together with other authors, recommend instead a "selective type of muscle activation, if we want more analytical.
The selective muscle activation implies that some muscle groups are activated according to the type of activity or perhaps it is better to say according to the type of exercise and their ability, lies in opposing external loads both actively and passively.
It remains incorrect to establish a priori that external load patterns during the cutting maneuver overload only the anterior cruciate ligament. There are passive lines of defense that are gradually involved, in a successive manner, with diversified load entities (tables 1,2,3,4,5)
It is right to point out and remember that the active defense lines of the knee, in response to valgus stresses, are given by:

tailoring

puny

semitendinosus

while the movement in var is opposed:

the tensor fascia lata.

It is clear, that from the above, a "selective muscle activation, according to the authors, would be, for example, the contraction of the gracilis, as opposed to a valgus load and external rotation.
In this selective co-contraction scheme, the medial component of the flexors and the quadriceps are co-activated, to oppose an external valgus load, while the flexors, lateral compartment and quadriceps are co-activated to oppose a varus load. .
In the other form, a simultaneous, simultaneous generalized flexor / extensor contraction is represented by the hamstrings and quadriceps which are co-activated without any selective medial or lateral muscle intervention. The activity of the knee flexors and extensors offers the greatest part of the stabilizer support for varus-valgus movements during sports activities
Lloyd showed that during the cutting maneuver, muscle activity can reduce the load, during the moments of varus-valgus, applied to the capsulo-ligamentous apparatus of the knee, by about 90%.
Summarizing the previously expressed concepts, co-contraction of the hamstring and quadriceps seems to be the best way to reduce the load on the anterior cruciate ligament, reducing anterior translation and contributing to the control of the varus and valgus moments of the knee.
Consequently, if the hamstring and quadriceps are voluntarily co-activated they will play an important role in stabilizing the knee during crossover cut maneuvers (when the change of direction is towards the same side of the body as the pivot leg) and sidestep cut. (when the change of direction is towards the side of the body opposite the pivot leg)
In the context of selective activation, it remains useful to remember that muscular activity is composed of active defense lines, which oppose the external rotation movement which are given by the quadriceps, sartorius, semitendinosus, semimembranous, popliteal muscles. and the tensor fascia lata represent the muscle groups active against the internal rotation movement.
The activity of the muscular apparatus contributes to amortizing external loads, reducing the femoro-tibial translation forces with a decrease in tension stress on the anterior cruciate ligament and on the capsulo-ligament apparatus.
The simultaneous contraction of the hamstring, quadriceps, gastrocnemius seems to be the ideal model of activation, to stabilize the knee at best.
In contrast, it seems appropriate to specify that the hamstrings work, almost always in basketball in a shortening position, thus losing the perceptive ability to work in lengthening.