Ativação muscular do quadril e do joelho em duas aterrissagens realizadas por atletas do sexo masculino

Abstract

Objective: To compare the myoelectric activity before and after ground contact between single-leg (SL) and double-leg (DL) landings in male athletes. Participants: Fifteen male volleyball athletes without signs and symptoms of lesions in the lower extremities, with a minimum of three years experience in the sport (13 ± 1 years, 1.70 ± 0.12 m, 60 ± 12 kg). Measurements: Participants performed two vertical jumps, landing unilaterally and bilaterally. The myoelectric activity of the rectus femoris (RF), biceps femoris (BF), hip adductors (HA) and the BF/RF ratio were compared between the two landings and between the phases characterized by 100ms before (PRE) and after 100 ms (POST) ground contactusing ANOVA two-way test with post hoc test of Bonferroni (α = 5%). Results: In both landings activation of RF was higher in the POST in relation to the PRE (p <0.0001). Comparing the landings in the same phase statistical differences (p = 0.2212) were not found. Although the BF did not present significant differences between the PRE and POST in each landing (p = 0.2321), its activation was higher in SL (p = 0.0051). The HA showed greater activation in the POST during the SL (p = 0.0013), however there were no differences when comparing the two landings (p = 0.9233). The BF/RF ratio was higher in both landings during PRE (p = 0.0012). Nevertheless, no differences between the landings (p = 0.7037) were found. Conclusion: The results suggest that each muscle has a different role during landing tasks in men. While RF has the main function to decelerate the knee and the downward movement, characterized by increased activation in the POST, BF seems to attenuate the loads on the knee in activities of higher impact, staying more active throughout the cycle in the SL. The increased activation of HA after ground contact in the SL highlights the importance of core region in stabilizing the pelvis in situations of great instability. Further studies are needed to determine the effects of muscle activation at the imposition of mechanical load on the knee that are potentially harmful to male athletes.

Intrasession Reliability of the Tests to Determine Lateral Asymmetry and Performance in Volleyball Players

“…Our results indicate that a greater lateral symmetry in the THTD test is related to a lower AJ (r = −0.58, p = 0.01), which is not easily explained. In the basic technique of the volleyball attack jump, the take-off is done with both feet at the same time [15], suggesting that there should be a better performance in the AJ the more symmetrical the player is, which is the opposite of what our results have shown.…”

“…Specifically, the jump is done with the drive of the two legs together, but opposite to the forward attack arm, to favor the hip-trunk rotation and to perform a greater force hitting the ball [14]. On the other hand, there is an eccentric landing action within each jump, with an involvement in the creation of these lateral decompensations, where 40% of the landing actions are performed on one leg [15]. All of this seems to indicate that this sport could generate lateral asymmetries that could affect the jumping or ball hitting performance.…”

Is the Rotatory Knee Stability Immediately Decreased Following a Competitive Soccer Match?

“…Our study has observed an acute pivoting knee adaptation where the fatigue induced by soccer playing appears to be the most relevant source of pivot shift alteration. As our results showed significant differences detected in the static pivot shift test but not in the dynamic pivoting landing task, the more knee muscle activation required during the landing of the pivoting task would help maintain the knee stability (Leporace et al, 2011), even if there was a decreased passive stability (laxity), such as the pivot shift maneuver suggests have occurred in our study.…”

“…As predicted, this finding was because of the dynamic pivoting landing task, which has shown more sensitivity to completing insufficient ACL (Pan et al, 2020). Instead, the dynamic testing increases the muscle activation to control the landing (Leporace et al, 2011). Therefore, the sensitivity to detect the axis movement alteration using the dynamic test following a competitive soccer match could be less than that with the pivot testing to find rotatory knee alterations in non-complete insufficient ACL.…”

Impaired Knee Muscle Capacity Is Correlated With Impaired Sagittal Kinematics During Jump Landing in Women With Patellofemoral Pain

“…Although lower knee extensor RFD to reach 60 and 90% of MIT was correlated with the reduced sagittal movements at the knee and hip, no relationships of hip muscle capacity with sagittal kinematics were identified. This suggests the quadriceps may be more important to control landing movements in comparison with the hip musculature (24). Improving ability to land with less stiffness (i.e., more flexion) (44) may require exercise therapy to improve quadriceps RFD, not just movement retraining, which is typically the focus of knee injury prevention programs (2).…”