Knee biomechanics changes under dual task during single-leg drop landing

Knee Biomechanics During Neurocognitively Challenged Drop Landings in Male Elite Soccer Players with Anterior Cruciate Ligament Reconstruction

BACKGROUND

Reactive decision-making during athletic movement has been demonstrated to evoke unfavorable biomechanics associated with anterior cruciate ligament (ACL) rupture. However, the current evidence is based on assessments of healthy individuals. We aimed to investigate unplanned jump landing kinetics and knee kinematics in ACL-reconstructed (ACLR) and non-injured athletes.

METHODS

A total of 30 male professional soccer players (n = 15 ACLR after return to play, n = 15 matched controls) performed six drop landings onto a force plate. As a neurocognitive challenge requiring decision-making, a diode flashing in randomly selected colors indicated the requested landing location. Knee joint kinematics (flexion, valgus and tibial rotation angles) assessed with a 10-camera motion capture system, vertical ground reaction force (vGRF), time to stabilization (TTS) and length of the center of pressure (COP) trace (all analyzed from force plate data) were calculated. Cognitive function was assessed using the CNS Vital Signs battery.

RESULTS

The ACLR group produced lower knee flexion angles than the control group (median [interquartile range] 50.00° [6.60] vs. 55.20° [4.45], p = .02). In addition, path length of the center of pressure (379 mm [56.20] vs. 344 mm [37.00], p = .04) and ground reaction force (3.21 N/kg [0.66] vs. 2.87 N/kg [0.48], p = .01) were higher for the ACLR group. No differences were found for knee valgus (p = .96), tibial rotation (p = .83) and TTS (p = .82). ACLR participants scored lower for reaction time (p = .02) and processing speed (p = .01). Unfavorable knee biomechanics were more often related to cognitive function in the ACLR group than in the control group (p < .05).

CONCLUSIONS

Impaired reactive decision-making during athletic movement may contribute to the high re-injury risk in individuals with ACLR. Prospective studies confirming potential cause-effect relationships are warranted.

Dual tasking increases kinematic and kinetic risk factors of ACL injury

ACL injuries are common among athletes playing team sports. The impact of divided attention during team sports on landing mechanics is unclear. Twenty-one healthy females jumped at a 60° angle to their right and performed a second jump to their right or left at a 60° angle. The direction of the second jump was shown before movement (baseline) or mid-flight of the first jump (dual task). The signal for the dual-task conditions showed five arrows and the middle one indicated the jump direction (Flanker paradigm). The other arrows pointed in the same (congruent) or the opposite (incongruent) direction as the middle arrow. Results indicated larger initial and peak knee flexion angles, smaller peak knee valgus moments, and smaller vertical and posterior GRFs during baseline right jumps compared to other conditions. Peak posterior GRF was increased in the incongruent condition compared to the congruent condition during left jumps. Performance was decreased with longer stance times for the dual task compared to the baseline in both jump directions. Further, the incongruent condition had a longer stance time than the congruent condition during left jumps. More research focusing on decision-making with more challenging visual stimuli mimicking dynamic team sports is merited.

Anticipatory effects on side-step cutting biomechanics in Women's Australian Football League players

Objectives

Reactive side-step cutting manoeuvres are linked to anterior cruciate ligament (ACL) injuries in Women's Australian Football League (AFLW) matches. We explored knee joint moments and ground reaction forces (GRFs) in AFLW players when performing anticipated and unanticipated side-stepping.

Methods

Sixteen AFLW players (age=25.3±4.2 years; height=1.71±0.06 m; mass=68.4±4.7 kg) completed anticipated and unanticipated side-stepping trials during which full-body three-dimensional kinematics and kinetics were recorded. One-dimensional statistical parametric mapping paired t-tests were used to compare three-dimensional knee moments during weight acceptance and GRFs during the stance phase between anticipated and unanticipated conditions.

Results

Unanticipated side-stepping incurred lower knee flexion (18%-39% of stance, p<0.01) and abduction (11%-24% of stance, p<0.01) moments. Braking and propulsive GRFs were lower and higher, respectively, across the majority of stance phase (6%-90% of stance, p<0.01) in unanticipated side-stepping. Vertical GRFs were lower in unanticipated side-stepping in the early stance phase (14%-29% of stance, p<0.01).

Conclusion

Contrary to existing literature, AFLW players exhibited knee joint moments associated with reduced ACL loading when performing unanticipated side-stepping. Players appeared to adopt a 'cautious' approach to the unanticipated side-step (ie, decelerating at the change of direction), by reducing braking and vertical GRFs in the early stance phase of cutting. This approach may be implausible to employ or detrimental to performance during matches. AFLW ACL injury prevention programmes may be enhanced with greater exposure to scenarios that replicate reactive match-play demands when aiming to improve side-stepping biomechanics.

Cognitive Load Influences Drop Jump Landing Mechanics During Cognitive-Motor-Simulated Shooting

INTRODUCTION

Military duties require immense cognitive-motor multitasks that may predispose soldiers to musculoskeletal injury. Most cognitive challenges performed in the research laboratory are not tactical athlete specific, limiting generalizability and transferability to in-field scenarios. The purpose of this study was to determine the impact of a cognitive-motor multitask (forward drop jump landing while simultaneously performing simulated shooting) on knee kinetics and kinematics.

METHODS

Twenty-four healthy collegiate Reserve Officer's Training Corps members (18 males and 6 females, 20.42 ± 1.28 years, 174.54 ± 10.69 cm, 78.11 ± 14.96 kg) volunteered, and knee kinetics and kinematics were assessed between baseline and cognitive-loaded conditions. Repeated measures ANOVAs were conducted for each dependent variable with the within-subject factor of condition (baseline vs. cognitive load).

RESULTS

Univariate ANOVAs indicated that knee flexion angle at initial contact (IC) (decreased 6.07°; d = 3.14), knee flexion displacement (increased 6.78°; d = 1.30), knee abduction angle at IC (increased 2.3°; d = 1.46), peak knee abduction angle (increased 3.04°; d = 0.77), and peak vertical ground reaction force (increased 0.81 N/kg; d = 2.13) were significant between conditions (P < .001). Therefore, cognitive load resulted in decreased knee flexion and increased knee abduction angle at IC and greater peak vertical ground reaction force, all factors commonly associated with knee injury risk. Peak knee flexion angle and knee abduction displacement were not significant between conditions (P > .05).

CONCLUSIONS

Cognitive challenge induced knee landing biomechanics commonly associated with injury risk. Injury risk screening or return-to-training or duty assessments in military personnel might consider both baseline and cognitive conditions.

Serial Subtraction Alters Lateral Step-down Tibiofemoral Kinematics in Healthy Adults

This study evaluated the effects of two types of cognitive dual-tasking on three-dimensional knee kinematics during the lateral step-down. 19 healthy individuals (22.05±1.61 yrs., 173.92±9.21 cm, 67.99±12.65 kg) participated in this study. Participants completed 5 repetitions of a lateral step-down task for each leg and each testing condition (control, Stroop, and serial subtraction by seven). An electromagnetic motion sensor was attached to the femur via compression clamp placed about the medial and lateral epicondyles. Another sensor was attached 2 cm below the ipsilateral tibial tuberosity. A custom MATLAB algorithm located the knee joint axis of rotation from dynamic knee flexion and extension. Discrete kinematics at peak flexion were used in this study. Paired samples t-tests were used to compare average frontal, transverse, and sagittal plane knee position at maximum flexion between conditions for each leg. No significant differences were found for either limb between control and Stroop conditions. Comparisons revealed significant differences in frontal and transverse plane knee angles at peak flexion between the control and serial subtraction by seven conditions. These findings indicate serial subtraction by seven requires different cognitive processing abilities which may cause greater interference with some aspects of motor control.

Relationship Between Posterior Tibial Slope and Lower Extremity Biomechanics During a Single-Leg Drop Landing Combined With a Cognitive Task in Athletes After ACL Reconstruction

Background:

A steeper posterior tibial slope (PTS) is an important risk factor for anterior cruciate ligament (ACL) reinjury. The PTS may affect lower extremity biomechanics under competition-like conditions for athletes with a reconstructed ACL.

Hypothesis:

It was hypothesized that the PTS would be associated with lower extremity biomechanics, which may increase ACL strain.

Study Design:

Descriptive laboratory study.

Methods:

Included were 10 athletes (mean age, 20.9 ± 1.8 years) who had undergone ACL reconstruction. The authors recorded the 3-dimensional lower extremity biomechanics while participants performed a single-leg drop jump with the Stroop task (dual task). Kinematic and kinetic data were analyzed and compared between the involved and contralateral limbs. The medial and lateral PTSs were measured using magnetic resonance imaging scans of the involved knee. The correlation between the biomechanical data and the PTS in each knee was evaluated.

Results:

The lateral PTS was significantly correlated with the maximum hip adduction moment (r = 0.64; P < .05) and maximum internal tibial rotation angle (r = 0.71; P < .05) in the involved limb. There were no differences in kinematic and kinetic data between the involved and contralateral limbs.

Conclusion:

In athletes after ACL reconstruction, the lateral PTS was directly associated with the maximum internal tibial rotation angle during single-leg drop landing with a cognitive task.

Clinical Relevance:

The findings in this study indicate that a steeper lateral PTS may cause internal rotation of the tibia during landing, which may be associated with reinjury in athletes with a reconstructed ACL.

Do ACL Injury Risk Reduction Exercises Reflect Common Injury Mechanisms? A Scoping Review of Injury Prevention Programs

CONTEXT

Anterior cruciate ligament (ACL) injury risk reduction programs have become increasingly popular. As ACL injuries continue to reflect high incidence rates, the continued optimization of current risk reduction programs, and the exercises contained within them, is warranted. The exercises must evolve to align with new etiology data, but there is concern that the exercises do not fully reflect the complexity of ACL injury mechanisms. It was outside the scope of this review to address each possible inciting event, rather the effort was directed at the elements more closely associated with the end point of movement during the injury mechanism.

OBJECTIVE

To examine if exercises designed to reduce the risk of ACL injury reflect key injury mechanisms: multiplanar movement, single limb stance, trunk and hip dissociative control, and a flight phase.

DATA SOURCES

A systematic search was performed using PubMed, Medline, EBSCO (CINAHL), SPORTSDiscus, and PEDro databases.

STUDY SELECTION

Eligibility criteria were as follows: (1) randomized controlled trials or prospective cohort studies, (2) male and/or female participants of any age, (3) exercises were targeted interventions to prevent ACL/knee injuries, and (4) individual exercises were listed and adequately detailed and excluded if program was unable to be replicated clinically.

STUDY DESIGN

Scoping review.

LEVEL OF EVIDENCE

Level 4.

DATA EXTRACTION

A total of 35 studies were included, and 1019 exercises were extracted for analysis.

RESULTS

The average Consensus on Exercise Reporting Template score was 11 (range, 0-14). The majority of exercises involved bilateral weightbearing (n = 418 of 1019; 41.0%), followed by single limb (n = 345 of 1019; 33.9%) and nonweightbearing (n = 256 of 1019; 25.1%). Only 20% of exercises incorporated more than 1 plane of movement, and the majority of exercises had sagittal plane dominance. Although 50% of exercises incorporated a flight phase, only half of these also involved single-leg weightbearing. Just 16% of exercises incorporated trunk and hip dissociation, and these were rarely combined with other key exercise elements. Only 13% of exercises challenged more than 2 key elements, and only 1% incorporated all 4 elements (multiplanar movements, single limb stance, trunk and hip dissociation, flight phase) simultaneously.

CONCLUSION

Many risk reduction exercises do not reflect the task-specific elements identified within ACL injury mechanisms. Addressing the underrepresentation of key elements (eg, trunk and hip dissociation, multiplanar movements) may optimize risk reduction in future trials.

Integrating neurocognitive challenges into injury prevention training: A clinical commentary

Despite the efforts of many traditional lower extremity injury prevention programs (IPP), the incidence of anterior cruciate ligament injuries in young athletes continues to rise. Current best practices for IPPs include training lower extremity neuromuscular control and movement quality during cutting, jumping, and pivoting. Emerging evidence indicates neurocognition may contribute to injury incidence and injury risk biomechanics. Therefore, IPP outcomes may improve if clinicians also consider neurocognitive contributions to neuromuscular control and athletic performance. A substantial barrier to neurocognitive challenge integration during injury prevention training in the group setting is the lack of structured neuromuscular and neurocognitive progressions. Therefore, our aim is to provide clinicians with a defined framework and recommendations from clinical experience for how to implement neurocognitive challenges within group IPPs that requires minimal extra time and resources. This clinical commentary proposes a three-phase model adopted from motor learning literature to simultaneously progress neuromuscular and neurocognitive challenges through a structured IPP.

The Effects of a Cognitive Dual Task on Jump-landing Movement Quality

Investigations on movement quality deficits associated with jump landing are numerous, however, these studies are often performed in laboratories with little distraction to the participant. This is contrary to how injury typically occurs secondary to sport-specific distraction where the athlete is cognitively loaded during motor performance. Thus, the purpose of this study was to determine the effect of a cognitive load on jump-landing movement quality. A dual-task design was used to determine the effects of a dual-task on tuck jump movement quality in 20 participants. There were three cognitive conditions (no cognitive task, easy-cognitive task, and difficult-cognitive task). The dual task elicited statistically significant changes in overall tuck jump score (movement quality) across the conditions with tuck jump score increasing from 3.52±1.64 baseline to 4.37±1.25 with the easy-cognitive task to 4.67±1.24 with the difficult-cognitive task. The findings of this study may be useful to screen for individuals at risk of lower extremity injury utilizing the tuck jump when paired with a cognitive task. The screening would then identify individuals who may have poor neuromuscular control when cognitively loaded.

Alterations in knee sensorimotor brain functional connectivity contributes to ACL injury in male high-school football players: a prospective neuroimaging analysis

OBJECTIVE

This study's purpose was to utilize a prospective dataset to examine differences in functional brain connectivity in male high school athletes who suffered an anterior cruciate ligament (ACL) injury relative to their non-injured peers.

METHODS

Sixty-two male high school football players were evaluated using functional magnetic resonance imaging prior to their competitive season to evaluate resting-state functional brain connectivity. Three athletes later experienced an ACL injury and were matched to 12 teammates who did not go on to sustain an ACL injury (controls) based on school, age, height, weight, and year in school. Twenty-five knee-motor regions of interest (ROIs) were created to identify differences in connectivity between the two groups. Between-subject F and t tests were used to identify significant ROI differences using a false discovery rate correction for multiple comparisons.

RESULTS

There was significantly less connectivity between the left secondary somatosensory cortex and the left supplementary motor area (p = 0.025), right pre-motor cortex (p = 0.026), right supplementary motor area (p = 0.026), left primary somatosensory cortex (superior division; p = 0.026), left primary somatosensory cortex (inferior division; p = 0.026), and left primary motor cortex (p = 0.048) for the ACL-injured compared to the control subjects. No other ROI-to-ROI comparisons were significantly different between the groups (all p > 0.05).

CONCLUSION

Our preliminary data indicate a potential sensorimotor disruption for male football players who go on to experience an ACL injury. Future studies with larger sample sizes and complementary measures of neuromuscular control are needed to support these findings.