Knee Muscular Control During Jump Landing in Multidirections

Is the Frequency of a Targeted Neuromuscular Training Program a Factor in Modifying Knee Joint Loading During Typical Netball Landing Tasks?

BACKGROUND

Unplanned sidestep cutting and forward single-leg jump-landing contribute to non-contact anterior cruciate ligament (ACL) injuries in netball. Neuromuscular training programs (NMTPs) have shown promising results in reducing injury risk in certain populations when compliance is high. Compliance is easier to achieve when NMTPs are effective yet require minimal time for completion.

HYPOTHESIS

Once- and thrice-weekly intervention groups would be equally effective in reducing knee abduction and internal rotation moments during forward single-leg jump landing and unplanned sidestep cutting.

STUDY DESIGN

Randomized controlled trial.

LEVEL OF EVIDENCE

Level 3.

METHODS

External peak knee abduction and peak knee internal rotation moments during unplanned sidestep cutting and forward single-leg jump-landing were assessed pre- and post-intervention for 17 elite-level female netballers assigned randomly to either a once-weekly or thrice-weekly group. Regular netball training continued throughout the intervention, which lasted 6 weeks (30 minutes/session). One-way analysis of covariance (α = 0.05) was utilized to compare post-intervention peak knee abduction and peak knee internal rotation moments between groups, controlling for pre-intervention knee moments during the forward single-leg jump-landing and unplanned sidestep cut. Paired t tests were used to examine within-group changes in knee moments pre- versus post-intervention.

RESULTS

For unplanned sidestep cuts on the right leg, both groups differed significantly, with the once-weekly group displaying a decrease in peak knee internal rotation moments [F(1,14) = 5.23; P = 0.04] whereas the thrice-weekly group did not. No other significant group interactions were found.

CONCLUSION

A condensed NMTP with targeted exercises, performed once-weekly as part of regular training, shows potential to reduce peak knee internal rotation moments that are injurious to the ACL during unplanned sidestep cutting in adult female netballers.

CLINICAL RELEVANCE

A once-weekly targeted NMTP would pose minimal disruption to a high-performing athlete's training schedule and likely increase compliance to ensure the success of the NMTP.

Biomechanical and neuromuscular comparison of single- and multi-planar jump tests and a side-cutting maneuver: Implications for ACL injury risk assessment

BACKGROUND

Non-contact anterior cruciate ligament (ACL) injuries are a major problem among adolescent female soccer and handball players. Therefore, the aim of this study was to examine if known biomechanical and neuromuscular ACL injury risk factors obtained from single-planar jump-landings and multi-planar side-jumps can resemble the demands of side-cutting maneuvers, a known high-risk ACL injury movement for this population.

METHODS

Twenty-four female soccer and handball players (mean ± SD: age: 17 ± 1 year; height: 172 ± 66 cm; mass: 67 ± 9 kg) performed a series of functional tasks including two single-planar jump-landings, two multi-planar side-jumps and a sports-specific side-cutting maneuver on their dominant leg. Frontal and sagittal plane knee and hip joint kinematics and kinetics were calculated from three-dimensional motion analysis, whereas hamstring and quadriceps muscle pre-activity levels were measured with surface electromyography.

RESULTS

The sports-specific side-cut was distinguished by more knee flexion at initial contact, greater abduction angles and external knee abduction moments, higher biceps femoris and semitendinosus muscle pre-activity levels than both the single-planar jump-landings and multi-planar side-jumps (p < .05). Whilst, poor-to-strong spearman rank correlation coefficients inconsistently were found for the biomechanical and neuromuscular ACL injury risk factors explored between the side-cut and the single-planar jump-landings (r_s = 0.01-0.78) and multi-planar side-jumps (r_s = 0.03-0.88) respectively.

CONCLUSION

Single-planar jump-landings and multi-planar side-jumps should be used with caution to test for non-contact ACL injury risk factors in adolescent female soccer and handball players, because they do not mimic the biomechanical nor neuromuscular demands of the most frequent injury situation.

The Effect of Angle and Velocity on Change of Direction Biomechanics: An Angle-Velocity Trade-Off

Changes of direction (CODs) are key manoeuvres linked to decisive moments in sport and are also key actions associated with lower limb injuries. During sport athletes perform a diverse range of CODs, from various approach velocities and angles, thus the ability to change direction safely and quickly is of great interest. To our knowledge, a comprehensive review examining the influence of angle and velocity on change of direction (COD) biomechanics does not exist. Findings of previous research indicate the biomechanical demands of CODs are 'angle' and 'velocity' dependent and are both critical factors that affect the technical execution of directional changes, deceleration and reacceleration requirements, knee joint loading, and lower limb muscle activity. Thus, these two factors regulate the progression and regression in COD intensity. Specifically, faster and sharper CODs elevate the relative risk of injury due to the greater associative knee joint loading; however, faster and sharper directional changes are key manoeuvres for successful performance in multidirectional sport, which subsequently creates a 'performance-injury conflict' for practitioners and athletes. This conflict, however, may be mediated by an athlete's physical capacity (i.e. ability to rapidly produce force and neuromuscular control). Furthermore, an 'angle-velocity trade-off' exists during CODs, whereby faster approaches compromise the execution of the intended COD; this is influenced by an athlete's physical capacity. Therefore, practitioners and researchers should acknowledge and understand the implications of angle and velocity on COD biomechanics when: (1) interpreting biomechanical research; (2) coaching COD technique; (3) designing and prescribing COD training and injury reduction programs; (4) conditioning athletes to tolerate the physical demands of directional changes; (5) screening COD technique; and (6) progressing and regressing COD intensity, specifically when working with novice or previously injured athletes rehabilitating from an injury.