Neurophysiological correlates of motor planning and movement initiation in ACL-reconstructed individuals: a case-control study

Enhancing Return to Alpine Skiing: Integrating Perceptual-Motor-Cognitive Considerations in Testing and Progressions: A Clinical Commentary

Alpine skiing poses significant risks for anterior cruciate ligament (ACL) injury at both recreational and professional levels, which is compounded by high rates of re-injury. Despite the existence of return to sport (RTS) and return to snow protocols, the frequency of ACL re-injury has not been mitigated, raising doubts about protocol effectiveness. Current RTS protocols primarily focus on biomechanical and neuromuscular factors in isolation, neglecting the important perceptual-motor-cognitive changes associated with ACL injuries and the high cognitive demands of skiing. The purpose of this clinical commentary is to address the perceptual-motor-cognitive demands specific to alpine skiing, evaluate RTS testing for skiers, and propose updated standards for testing and return to snow progressions that incorporate these considerations.

Level of Evidence

5.

Associations Between Cognitive Function and ACL Injury-Related Biomechanics: A Systematic Review

CONTEXT

Does lower baseline cognitive function predispose athletes to ACL injury risk, especially when performing unplanned or dual-task movements?

OBJECTIVE

To evaluate the association between cognitive function and biomechanics related to ACL injuries during cognitively challenging sports movements.

DATA SOURCES

PubMed (MEDLINE), Web of Science, Scopus, and SciELO databases were searched; additional hand searching was also conducted.

STUDY SELECTION

The following inclusion criteria had to be met: participants completed (1) a neurocognitive test, (2) a cognitively challenging sport-related task involving lower limbs, and (3) a biomechanical analysis. The following criteria determined exclusion from the review: studies involving participants with (1) recent or current musculoskeletal injuries; (2) recent or current concussion; (3) ACL surgical reconstruction, reviews of the literature, commentary or opinion articles, and case studies.

STUDY DESIGN

Systematic review using the Preferred Reporting Items for Systematic Reviews and Meta-Analysis Protocols (PRISMA-P) statement and registered at the International Prospective Register of Systematic Reviews (PROSPERO).

LEVEL OF EVIDENCE

Level 3.

DATA EXTRACTION

Two of authors independently extracted data and assessed the methodological quality of the articles with the Downs and Black and ROBINS-I checklists, to assess methodological quality and risk of bias, respectively.

RESULTS

Six studies with different methodologies and confounding factors were included in this review. Of these 6 studies, 3 were ranked as high-quality, 3 demonstrated a low risk of bias, 2 a moderate risk, and 1 a severe risk. Five studies found a cognitive-motor relationship, with worse cognitive performance associated with increased injury risk, with 1 study reporting the opposite directionality for 1 variable. One study did not identify any interaction between cognitive function and biomechanical outcomes.

CONCLUSION

Worse cognitive performance is associated with an increased injury risk profile during cognitively challenging movements.

The Longitudinal Neurophysiological Adaptation of a Division I Female Lacrosse Player Following Anterior Cruciate Rupture and Repair: A Case Report

Background

Neurophysiological adaptation following anterior cruciate ligament (ACL) rupture and repair (ACLR) is critical in establishing neural pathways during the rehabilitation process. However, there is limited objective measures available to assess neurological and physiological markers of rehabilitation.

Purpose

To investigate the innovative use of quantitative electroencephalography (qEEG) to monitor the longitudinal change in brain and central nervous systems activity while measuring musculoskeletal function during an anterior cruciate ligament repair rehabilitation.

Case Description

A 19 year-old, right-handed, Division I NCAA female lacrosse midfielder suffered an anterior cruciate ligament rupture, with a tear to the posterior horn of the lateral meniscus of the right knee. Arthroscopic reconstruction utilizing a hamstring autograft and a 5% lateral meniscectomy was performed. An evidence-based ACLR rehabilitation protocol was implemented while using qEEG.

Outcomes

Central nervous system, brain performance and musculoskeletal functional biomarkers were monitored longitudinally at three separate time points following anterior cruciate injury: twenty-four hours post ACL rupture, one month and 10 months following ACLR surgery. Biological markers of stress, recovery, brain workload, attention and physiological arousal levels yielded elevated stress determinants in the acute stages of injury and were accompanied with noted brain alterations. Brain and musculoskeletal dysfunction longitudinally reveal a neurophysiological acute compensation and recovering accommodations from time point one to three. Biological responses to stress, brain workload, arousal, attention and brain connectivity all improved over time.

Discussion

The neurophysiological responses following acute ACL rupture demonstrates significant dysfunction and asymmetries neurocognitively and physiologically. Initial qEEG assessments revealed hypoconnectivity and brain state dysregulation. Progressive enhanced brain efficiency and functional task progressions associated with ACLR rehabilitation had notable simultaneous improvements. There may be a role for monitoring CNS/brain state throughout rehabilitation and return to play. Future studies should investigate the use of qEEG and neurophysiological properties in tandem during the rehabilitation progression and return to play.

Acute effects of a neuromuscular warm-up on potential re-injury risk factors associated with unanticipated jump landings after anterior cruciate ligament reconstruction: A crossover trial

OBJECTIVE

To investigate acute effects of a single bout of football specific neuromuscular injury preventive warm-up on potential anterior cruciate ligament (ACL) re-injury risk factors during anticipated and unanticipated jump-landings.

DESIGN

Crossover.

METHODS

Fourteen participants (mean ± SD age, 23.4 ± 4.1 years) 6-24 months after ACL reconstruction performed the Prevent Injury and Enhance Performance (PEP) and bicycle ergometer warm-up in a randomised sequence. Washout phase was one week. Countermovement jumps with anticipated and unanticipated single-leg-landings were assessed. Decision-making quality was measured using landing error count.

RESULTS

No carry-over effects occurred (p > 0.05). The unanticipated task produced significantly higher peak ground reaction forces (Δ+4%, F₍₁₁₎ = 3.46, p < 0.001, eta² = 0.21) after PEP warm-up compared to ergometer warm-up. A lower number of decision (Δ+12%, F ₍₅₎ = 17.1, p < 0.001, eta² = 0.57) and cumulated (Δ+15%, F ₍₃₎ = 17.2, p < 0.001, eta² = 0.57) errors were recorded during the unanticipated condition following PEP compared to ergometer warm-up.

CONCLUSIONS

Evaluating unanticipated jump-landing ability prior to return to sports clearance may provide information on potential re-injury risk factors. PEP warm-up may be superior to bicycle ergometer warm-up at improving unanticipated decision-making quality among athletes cleared to return to sports.

Cortical Motor Planning and Biomechanical Stability During Unplanned Jump-Landings in Males With ACL-Reconstruction

CONTEXT

Athletes with anterior cruciate ligament (ACL) reconstruction exhibit increased cortical motor planning during simple sensorimotor tasks compared to healthy controls. This may interfere with proper decision-making during time-constrained movements elevating the re-injury risk.

OBJECTIVE

To compare cortical motor planning and biomechanical stability during jump-landings between participants with ACL-reconstruction and healthy individuals.

DESIGN

Cross-sectional exploratory study.

SETTING

Laboratory patients or other participants: Ten males with ACL-reconstruction (28±4 yrs., 63±35 months post-surgery) and 17 healthy males (28±4 yrs.) completed pre-planned (landing leg shown before take-off; n=43±4) and unplanned (visual cue during flight; n=51±5) countermovement-jumps with single-leg-landings.

MAIN OUTCOME MEASURES

Movement-related cortical potentials (MRCP) and frontal theta frequency power before the jump were analyzed using electroencephalography. MRCP were subdivided into three successive 0.5 sec epochs (readiness potential 1 and 2; RP and negative slope; NS) relative to movement onset (higher values indicative of more motor planning). Theta power was calculated for the last 0.5 sec prior to movement onset (higher values indicative of more focused attention). Biomechanical landing stability was measured via vertical peak ground reaction force, time to stabilization, and center of pressure.

RESULTS

Both conditions evoked MRCP at all epochs in both groups. During the unplanned condition, the ACL-reconstructed group exhibited slightly, but not significantly higher MRCP (RP-1:p=0.651, d=0.44, RP-2:p=0.451, d=0.48; NS:p=0.482, d=0.41). The ACL-reconstructed group also showed slightly higher theta power values during the pre-planned (p=0.175, d=0.5) and unplanned condition (p=0.422, d=0.3) reaching small to moderate effect sizes. In none of the biomechanical outcomes, both groups differed significantly (p>0.05). No significant condition and group interactions occurred (p>0.05).

CONCLUSIONS

Our jump-landing task evoked MRCP. Although not significant between groups, the observed effect sizes provide first indication that males with ACL-reconstruction may persistently rely on more cortical motor planning associated with unplanned jump-landings. Confirmatory studies with larger sample sizes are warranted.

TRIAL REGISTRY

clinicalTrials.gov (NCT03336060).

Changes in motor-flexibility following anterior cruciate ligament reconstruction as measured by means of a leg-amplitude differentiation task with haptic and visual feedback

BACKGROUND

In the current study changes in lower-limb motor flexibility of patients undergoing Anterior Cruciate Ligament Reconstruction were evaluated in relation to fear of harm.

METHODS

Fourteen patients were measured pre- and post-surgery, and data were compared to those of a single measurement in fifteen controls. Lower-limb motor-flexibility was assessed in treadmill-walking and a cyclic leg-amplitude differentiation task augmented with haptic or visual feedback. Flexibility was captured by determining the between-leg coordination-variability (SD of relative phase) and each leg's temporal variability (sample entropy). Patients were post hoc divided into a higher-fear-group (pre-surgery: n = 6, post-surgery: n = 7) and a lower-fear-group (pre-surgery: n = 6, post-surgery: n = 7) by means of a median split of their scores on a self-reported fear of harm scale. Differences in flexibility-measures between the higher-fear-group and the lower-fear-group were also assessed.

FINDINGS

No pre- and post-surgery differences, nor differences with the control group, were found in motor-flexibility during treadmill-walking but the post-surgery higher-fear-group did show lower values of SD relative phase. In the leg-amplitude differentiation task the SD of the relative phase decreased but sample entropy increased post-surgery towards levels of the control-group. The pre-surgery higher-fear-group showed lower values of sample entropy in visual conditions.

INTERPRETATION

While gait kinematics may not show motor-flexibility changes following anterior cruciate ligament reconstruction, a leg-amplitude differentiation task does show such changes. Differentiating patients on a fear-of-harm scale revealed subtle differences in motor-flexibility. Challenging patients with non-preferred movements such as amplitude differentiation may be a promising tool to evaluate motor-flexibility following ACLR.

Lower Extremity Open Skill Training Effects on Perception of Visual Stimuli, Cognitive Processing, and Performance

This study investigates if lower extremity open-skill training impacts perception and cognitive processing abilities or just influences task related motor abilities. Twenty-two participants (24.7 ± 2.4years; 11 males, 11 females) were randomly allocated either into the group that trained on a computerized device or to the control group. Prior to and following the 4-week study period, motor performance was assessed using drop jump, hexagon test, postural control and lower extremity choice reaction. Perception, cognitive processing and task inhibition were captured using validated neurocognitive tests. Repeated measurements analyses of co-variances (ANCOVAs) were performed. They revealed a time (before and after intervention) × group (training vs. control) effect on lower extremity choice reaction and hexagon (p < .05). No effects on group differences or between groups in cognitive performance were found. A detrimental effect of training on accuracy of task inhibition (lower percentage of correct inhibitions) was detected. Computerized open skill training affects specific movement patterns without increasing task-relevant cognitive or perceptual abilities. Indicated by the lower percentage of correct inhibitions, the training might further detrimentally influence the risk-taking behavior during choice reaction tasks.

Unanticipated jump-landing quality in patients with anterior cruciate ligament reconstruction: How long after the surgery and return to sport does the re-injury risk factor persist?

BACKGROUND

Inadequate reactions to unforeseen external stimuli are regarded as a major cause for non-contact anterior cruciate ligament (ACL) injuries. We aimed to delineate a potential deficit in the ability to perform unanticipated jump-landing manoeuvres, its sustainability and potential as a new outcome measure after ACL-reconstruction.

METHODS

Physically active adults (n = 27, 13 females, 14 males, 29.7 standard deviation 3.1 years) with a history of unilateral ACL rupture and subsequent reconstruction (6 months to 7 years ago), cleared for return to sports, were included. All participants performed counter-movement jumps with unanticipated single leg landings. Visual information shown after jump take-off indicated the required landing leg. Jump time [s] and successfulness [yes/no], vertical peak ground reaction forces at landing [N], as well as time to stabilisation after landing [s] and path length of the centre of pressure (CoP, [mm]) were calculated. Limb symmetry ratios were determined and analysed for their association with the time since surgery.

FINDINGS

Time since ACL reconstruction was logarithmically (basis 10) associated with side symmetry improvements in peak ground reaction force (R² = 0.23, p < .01) and time to stabilisation (R² = 0.18, p < .01) during and after landing in unanticipated/unpredictable single-leg jump landing tasks. The asymmetry found persists up to 18-26 months post-surgery.

INTERPRETATION

A deficit in unanticipated jump-landing ability seems to persist far beyond surgical restoration of mechanical stability and resumption of initial physical activities levels. The assessment of the ability to suddenly adapt movements to unanticipated visual stimuli may be a relevant complementary component within current functional testing canon in monitoring therapy success and return to sport testing.

Unanticipated jump-landing after anterior cruciate ligament reconstruction: Does unanticipated jump-landing testing deliver additional return to sport information to traditional jump performance tests?

BACKGROUND

We aimed to delineate if unanticipated jump-landing assessments delivers complementary information to those of commonly used hop and jump tests after anterior cruciate ligament reconstruction.

METHODS

Eleven participants (5 males) performed a series of unanticipated jump-landings and traditional hop and jump performance tests (single leg hops for distance, triple crossover hops for distance and drop jumps). The number of mistrials, time to stabilization and peak ground reaction force (pGRF) at landing and jump/hop distance were measured. Pearson correlations to find potential associations between the unanticipated jump-landing-values and the traditional jump/hop performance tests were calculated twice: once for the affected and once for the unaffected legs. t-Tests for dependent samples were used to detect differences between affected and unaffected leg within each test condition.

FINDINGS

The pGRF at unanticipated landing significantly correlated to the pGRF at drop jump landing (r = 0.68) and the hopping distance after the triple crossover hops (r = 0.71, each p < .05). No other significant correlation occurred (p > .05). Hopping distance after single leg hops (mean: 110.2 cm vs. 95.5 cm) and triple crossover hops for distance (mean: 315.3 cm vs. 294.2 cm) showed significant differences between the unaffected and the reconstructed leg (p < .05). Other parameters showed no significant between-legs differences (p > .05).

INTERPRETATION

Both, the reconstructed and the contralateral leg seems to be affected. Unanticipated jump landing tasks deliver information beyond those of commonly used jump and hop tests, the thereby assessed abilities may thus be a complementary aspect of dynamic knee function than those assessed with classic tests.

Acute effects of preventive warm-up exercises on modifiable risk factors for anterior cruciate ligament injuries: a three-arm randomized-controlled crossover trial

BACKGROUND

We aimed to compare the potential acute effects of single bouts of a classic prevention and a risk factor-focus training aiming to target modifiable anterior cruciate ligament (ACL) rupture risk factors and the impact of neuromuscular fatigue on relevant ACL rupture risk factors.

METHODS

Two preventive warm-up (standard and ACL rupture risk factor training) and one inactive arm were compared; each of these were followed by a standardized neuromuscular fatigue protocol. The assessments included two Trail making tests (TMT-A; TMT-B, time to complete), drop jump landings (knee separation distance, normalized at hip width), as well as unanticipated counter movement jump landings (time to stabilization and peak ground reaction force).

RESULTS

We included 18 participants (25±2years). No differences were found between times and conditions for TMT (P>0.05). A significant time effect occurred in time to stabilization (F=2.6; P<0.05) and a significant time*baseline-value*jumping time interaction was seen in peak ground reaction force (F=3.1; P<0.05). No time effect was found for any knee separation distance (F=.1-2.4; P>0.05); but a significant time*baseline-value*jumping time interaction was seen at initial ground contact (F=2.8; P<0.05), and lowest point (F=4.2; P<0.01).

CONCLUSIONS

Risk factor-focus and classic warm-up may not differ in their acute effects on modifiable functional ACL (re-)injury risks factors.