Anterior cruciate ligament (ACL) injuries are frequent in handball especially among young players. Recent investigations highlighted the implication of the central nervous system as a potential risk factor for ACL rupture. The ability to dynamically reweight proprioceptive signals according to postural conditions is crucial for balance control. The aim of this study is therefore to investigate the influence of proprioceptive reweighting on biomechanical determinants of ACL loads during functional tasks and unplanned side cutting manoeuvers.
Team Handball is a traumatic sport, especially regarding anterior cruciate ligament (ACL) injuries. Young females are more vulnerable as they are 3 to 5 times more likely to sustain an ACL rupture compare to males. Several anatomical, biomechanical and sensorimotor risk factors have been clearly identified, however the implication of the central nervous system was recently highlighted. Indeed, it has been shown that individuals who will suffer of ACL ruptures exhibited a decreased functional connectivity between brain regions responsible for postural control and sensorimotor processing. Due to the unanticipated situations that occurred during game situations, the role of the brain (i.e neural control) is now advocated to explain sensorimotor errors leading to injuries during complex tasks such as faking an opponent. Muscle vibration is a reliable tool to assess proprioceptive integration during postural control. The ability to shift from one proprioceptive cue to another when postural conditions are changing is crucial. This dynamic reweighting process allow to obtain an optimal postural control. However, recent investigations revealed that this process is altered among symptomatic populations, elderly patients or even under fatigue conditions. More precisely, some individuals seem able to shift proprioceptive reliance while other doesn't. To our knowledge, no studies have investigated the link between proprioceptive reweighting and biomechanical determinants of ACL loads during functional tasks. Thus, the aim of this study is to compare lower-limb biomechanics during unanticipated side cutting manoeuvres and single leg drop vertical jump among young handball players according to their ability to reweight proprioceptive signals.
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
BASIC_SCIENCE
Masking
NONE
Enrollment
41
The subject will be in unipodal support (only one foot on the ground) on the tested lower limb in the center of the platform. Three lines forming a "Y" will be arranged according to the lower limb in charge in three directions : anterior (ANT), posteromedial (PM) and posterolateral (PL). The goal is then to reach the longest distance possible in all three directions with the tip of the foot in relief before returning to the starting position. The subject will have 4 training trials per direction on each lower limb then 3 trials will be recorded in order to keep the average.
The subject will drop from a step and land on one leg, then jump as high as possible and stabilize again on the same leg. The height of the step is 30 cm. The subject will perform 3 consecutive jumps in the strictest respect of the instructions: drop to the level of the mark on the ground and bounce as high as possible while spending a minimum of time on the ground. The subject must stabilize for 3 seconds during the second contact with the ground so that the instructions and measurements are reproducible.
The objective is to create an unanticipated playing situation, close to the daily actions of the subjects in the practice of handball. The subject will make sidestep cutting manœuvre in front of an opponent simulated by a dummy used during usual training. The subject will sprint in a straight line and then at the force platform will make a rapid change of direction on the side of his shooting arm or will continue his run in a straight line. A light signal randomly will indicate to the player the direction in which he must carry out his manoeuvre. A computer reconstruction of the kinematics and dynamics (knee moment) will be performed.
The subject will be asked to stand, motionless in bipodal (both feet on the ground) support on a stable and unstable ground (foam). A tendon vibration (80Hz) will be randomly applied to the subject in the Achilles tendons or paravertebral muscles. This vibration will cause an alteration of proprioceptive information in the vibrated area leading to a disruption of postural balance. Thus, according to the amount of displacement of the center of pressure (CoP), the proprioceptive weighting ratio (dRPW) is calculated to deduce therefrom the weight assigned by the CNS to the various proprioceptive inputs during the postural task.
CHRU Brest
Brest, France, France
Knee abduction moment (quantitative measure) during unplanned sidestep cutting manœuvre.
The measurement will be the average of the maximum knee abduction moments when the lower extremity is supported on the pushing leg, over the 5 tests carried out with a sidestep cutting manœuvre.
Time frame: Inclusion
Knee abduction moment when landing jumps in the Single leg Drop Vertical Jump.
The measurement will be made on the average of the abduction moments of the knee when landing the jump on the ground. The subject will perform 3 consecutive jumps in the strictest respect of the instructions.
Time frame: Inclusion
Star Excursion Balance Test performance.
The value obtained (in centimeters or relative to the length of the lower limb) reflects the dynamic postural performance of the lower limb under load without specificity of a particular joint of the lower limb. The subject will have 4 training trials per direction on each lower limb then 3 trials will be recorded in order to keep the average.
Time frame: Inclusion
Angles of ankles, knees, hips, orientation of the pelvis during changes of direction.
The angles, in degrees, of ankles, knees, hips and orientation of the pelvis during changes of direction will be determined during the unplanned sidestep cutting manœuvre test by computer reconstruction. The values will allow to compare biomechanicals characteristics according to the proprioceptive profile (plastic subjects vs rigid subjects).
Time frame: Inclusion
Percentage of subjects with a proprioceptive plastic profile.
A dRPW of 1 indicates 100% use of information from the ankle, while a dRPW of 0 indicates 100% use of information from the hip. It is thus possible to calculate an evolution of this dRPW during the passage from a stable to unstable soil. The "plastic" subjects decreases their dRPW on unstable ground (compared to stable) ("normal" behavior). "Rigid" subjects maintain (or even increase) their dRPW when passing over unstable ground.
Time frame: Inclusion
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