A systematic video analysis of 21 anterior cruciate ligament injuries in elite netball players during games

The effect of the KNEE program for Netball players on the modified Star Excursion Balance Test - a randomized controlled trial

BACKGROUND

The aim was to investigate the effect of the KNEE program on postural control as measured by the modified Star Excursion Balance test (mSEBT) in Australian club level netball players.

METHODS

Two netball teams from Netball NSW Premier-League were recruited and randomized to complete either the KNEE program or a traditional warm-up. Cumulative, anterior, posteromedial, and posterolateral directions of the mSEBT were measured for both limbs at baseline, 8-weeks, and 5-months. Linear mixed models were used to assess the effect of the intervention on mSEBT outcomes.

RESULTS

When compared to a traditional warm-up, the KNEE program led to improvements in postural control in the PM direction of the mSEBT at 8 weeks (R: p = 0.005; L = 0.016) and 5 months (R: p = 0.006 and L: p = 0.026). For the cumulative score, there was a main effect of time with significant improvements between baseline and subsequent time points (p < 0.03), but there was no effect of group or interaction. No significant changes were found in ANT and PL directions.

CONCLUSION

The KNEE program when implemented as a warm-up prior to training and match-play can improve postural control in the PM direction which is integral to Netball.

Effect of an overhead goal on landing error scoring system and jump height measures

OBJECTIVES

Compare overall Landing Error Scoring System (LESS) scores, risk categorisation, specific LESS errors, and double-leg jump-landing jump heights between overhead goal and no goal conditions.

DESIGN

Randomised cross-over.

SETTING

Laboratory.

PARTICIPANTS

76 (51% male).

MAIN OUTCOME MEASURES

Participants landed from a 30-cm box to 50% of their body height and immediately jumped vertically for maximum height. Participants completed three trials under two random-ordered conditions: with and without overhead goal. Group-level mean LESS scores, risk categorisation (5-error threshold), specific landing errors, and jump heights were compared between conditions.

RESULTS

Mean LESS scores were greater (0.3 errors, p < 0.001) with the overhead goal, but this small difference was not clinically meaningful. Similarly, although the number of high-risk participants was greater with the overhead goal (p = 0.039), the 9.2% difference was trivial. Participants jumped 2.7 cm higher with the overhead goal (p < 0.001) without affecting the occurrence of any specific LESS errors.

DISCUSSION

Performing the LESS with an overhead goal enhances sport specificity and elicits greater vertical jump performances with minimal change in landing errors and injury-risk categorisation. Adding an overhead goal to LESS might enhance its suitability for injury risk screening, although the predictive value of LESS with an overhead goal needs confirmation.

Indirect contact matters: Mid-flight external trunk perturbation increased unilateral anterior cruciate ligament loading variables during jump-landings

BACKGROUND

To determine the effect of unanticipated mid-flight medial-lateral external perturbation of the upper or lower trunk on anterior cruciate ligament (ACL) loading variables during jump-landings.

METHODS

Thirty-two participants performed double-leg vertical jump-landings while bilateral kinematics and kinetics were collected under 6 conditions (upper or lower trunk perturbation locations; no, left, or right perturbation directions). Two customized catapult apparatuses were created to apply pushing perturbation to participants near the maximal jump height.

RESULTS

The ball contacted participants near the center of mass for the lower-trunk conditions and approximately 23 cm above the center of mass for the upper-trunk conditions. Under upper-trunk perturbation, the contralateral leg demonstrated significantly smaller knee flexion angles at initial contact and greater peak knee abduction angles, peak vertical ground reaction forces, peak knee extension moments, and peak knee adduction moments compared to other legs among all conditions. Under lower-trunk perturbation, the contralateral leg showed significantly smaller knee flexion angles at initial contact and increased peak vertical ground reaction forces and peak knee extension moments compared to legs in the no-perturbation conditions.

CONCLUSION

Mid-flight external trunk pushing perturbation increased ACL loading variables for the leg contralateral to the perturbation. The upper-trunk perturbation resulted in greater changes in ACL loading variables compared to the lower-trunk perturbation, likely due to trunk and ipsilateral leg rotation and more laterally located center of mass relative to the contralateral leg. These findings may help us understand the mechanisms of indirect-contact ACL injuries and develop jump-landing training strategies under mid-flight trunk perturbation to better prevent ACL injury.

Biomechanical Analysis and Training Method Research on Head Shot Strength of Football Players

With the development of intelligent sports in China and the rapid improvement of the strength of colleges and universities, the reform of traditional football players' header shooting training methods is becoming more and more urgent in order to solve some problems in the development of sports and speed up the intelligent training of Chinese football players. Based on this, this paper studies the biomechanical analysis and training method based on the integration of header strength data of football players. A dynamic header tracking model of football players based on a local search algorithm is designed. The data collection is realized from the aspects of athletes' header shooting training, skill improvement, physical consumption, and trajectory. The biological data of header shooting power is comprehensively analyzed and evaluated by using a local search algorithm. The results show that the training system based on a local search algorithm has the advantages of high feasibility, high data accuracy, and fast response speed. It can effectively conduct accurate guidance and improve the shooting accuracy according to the biological characteristics of header shooting intensity. This paper studies the biological analysis and training method of header strength of football players based on a local search algorithm. This has certain reference significance for accelerating the construction of intelligent training of Chinese football players.