Acute Effects of ACL Injury-Prevention Warm-Up and Soccer-Specific Fatigue Protocol on Dynamic Knee Valgus in Youth Male Soccer Players

Abstract

Childhood anterior cruciate ligament (ACL) injuries—which can pose a major risk to a child’s sporting career—have been on the rise in the last few decades. Dynamic knee valgus (DKV) has been linked to an increased risk of ACL injury. Therefore, the aim of this study was to analyze the acute effects of an ACL injury prevention protocol (ACL-IPP) and a soccer-specific fatigue protocol (SSFP) on DKV in youth male soccer players. The research hypothesis was that DKV would be reduced by the ACL-IPP and increased by the SSFP. Eighteen youth male soccer players were divided according to baseline DKV. Those with moderate or large DKV performed a neuromuscular training protocol based on activation of the abductor and external rotator hip muscles. Those with little or no DKV performed a soccer-specific fatigue protocol. DKV was assessed using the single-leg squat pre- and post-protocols in both legs. The ACL-IPP significantly decreased DKV during single-leg squat (p < 0.01, effect size = 1.39), while the SSFP significantly increased baseline DKV in the dominant leg during single-leg squat (p = 0.012; effect size = 1.74). In conclusion, the ACL-IPP appears to acutely reduce the DKV in youth male soccer players, and the SSFP seems to acutely increase the DKV in those players who showed a light or no DKV in a non-fatigue situation. By using the SSFP, it may be possible to determine which players would benefit from injury prevention programs due to increased DKV during game scenarios, while hip abductor and external rotator neuromuscular training may be beneficial for players who have moderate and severe DKV during single-leg squat under non-fatigued scenarios.

Normative data and correlation between dynamic knee valgus and neuromuscular response among healthy active males: a cross-sectional study

“…It is known that hip and knee muscle function have a crucial role controlling the knee position 40 , 41 . However, the current evidence suggests that it is not only a question about muscle characteristics but about motor control 13 , 15 . Motor control means the ability to control movements during functional activities such as jumping, running, squatting, pivoting, etc 42 .…”

“…Specifically, athletes with poor glutes and hamstring activation are more likely to collapse the knee during a landing and then, potentially increasing the risk of non-contact ACL injury 14 . In fact, a protocol for neuromuscular activation of the abductors and external hip rotators during warm-up has recently been shown to reduce the DKV by 53–63% in youth male soccer players 15 . The relation between hip strength and the dynamic knee valgus seems to be clear 16 , but a possible relation between DKV and neuromuscular response (NMR) as contraction time, stiffness, tone or muscular displacement remain unstudied.…”

Effect of the FIFA 11+ soccer specific warm up programme on the incidence of injuries: A cluster-randomised controlled trial

“…Studies have examined the effects of several interventions in preventing injuries in soccer using one or more strategies [14][15][16][17][18][19][20]. An orthosis have been reported to be supportive after previous ankle injuries but no effect was found for initial injuries [15,16].…”

An Exemplar Frontal Plane Visual Kinematic Stimulus Elicits Sex-Specific Learned Behavior: An Exploratory Report

“…Despite decades of sex-specific injury mechanistic research (42), little headway has been gained in the advancement of ACL injury prevention efforts in male subjects. Although preliminary evidence does indicate male subjects to be receptive to well-implemented injury prevention programs (20,47), such programs were largely designed with female subjects in mind.…”