The Effect of Neurocognitive Training on Biomechanical Risk Factors Related to Anterior Cruciate Ligament Injury in Athletes: A Narrative Review.

CONTEXT: The best current evidence supports the effectiveness of neuromuscular training in reducing the risk of injury; however, the rate of anterior cruciate ligament (ACL) injuries is still high. Neurocognitive training (NT) has successfully improved biomechanical risk factors, but they have been considered in only a few studies. OBJECTIVE: To review the literature to determine the effect of NT on biomechanical risk factors related to ACL injury in athletes. EVIDENCE ACQUISITION: We searched PubMed, Google Scholar, Scopus, Science Direct, and the Physiotherapy Evidence Database from inception to August 2011. We included randomized controlled trials that used motor learning approaches and injury prevention programs to investigate kinematic and kinetic risk factors related to ACL injury. The quality of each clinical trial study was evaluated by the Physiotherapy Evidence Database scale. The eligibility criteria were checked based on the PICOS (population, intervention, comparison, outcome, and study type) framework. EVIDENCE SYNTHESIS: A total of 9 studies were included in the final analysis. Motor learning approaches include internal and external focus of attention, dual tasks, visual motor training, self-control feedback, differential learning, and linear and nonlinear pedagogy, combined with exercise programs. In most of the studies that used NT, a significant decrease in knee valgus; tibial abduction and external rotation; ground reaction force; and an increase in knee-, trunk-, hip-, and knee-flexion moment was observed. CONCLUSION: In classical NT, deviation from the ideal movement pattern especially emphasizing variability and self-discovery processes is functional in injury prevention and may mitigate biomechanical risk factors of ACL injuries in athletes. Practitioners are advised to use sport-specific cognitive tasks in combination with neuromuscular training to simulate loads of the competitive environment. This may improve ACL injury risk reduction and rehabilitation programs.

Differences in Gluteal and Quadriceps Muscle Activation Among Adults With and Without Lumbar Hyperlordosis.

CONTEXT: Many factors have been reported contributing to altering the neuromuscular function of hip and knee muscles. The lumbar hyperlordosis, as a poor posture in some athletes, is thought to be associated with the alteration of the hip and knee muscles activity. OBJECTIVE: To examine the activation of selected hip and knee muscles in athletes with and without lumbar hyperlordosis during functional activities. DESIGN: Case-control study. SETTING: University laboratory. PARTICIPANTS: Twenty-six college male athletes (n = 13 with and n = 13 without lumbar hyperlordosis). INTERVENTIONS: Surface electromyography of gluteus maximus (GMAX), gluteus medius (GMED), vastus medialis oblique (VMO), and vastus lateralis (VL) were recorded during single-leg squat and single-leg jump landing (SLJL) tasks. MAIN OUTCOME MEASURE: Preactivity; reactivity; and onset muscle during SLJL and eccentric activity during single-leg squat (GMAX, GMED, VMO, and VL along with the ratio of VMO:VL) were assessed. RESULTS: Athletes with lumbar hyperlordosis had a higher level of activity in their GMAX (P = .003), VMO (P = .04), and VL (P = .01) muscles at the moment before foot contact during SLJL. These athletes also demonstrated a higher level of GMAX activity (P = .01) immediately after foot contact. Finally, athletes with lumbar hyperlordosis activated their GMAX sooner (P = .02) during the SLJL. Athletes with normal lumbar lordosis had more activity in their GMED muscle (P = .001) in the descending phase of the single-leg squat task and a higher VMO:VL (P = .01) at the moment after the foot contact during the SLJL. CONCLUSION: The altered activation of GMAX, GMED, VMO, VL, and VMO:VL can reveal the role of lumbar hyperlordosis in the knee and hip muscles' alteration in athletes. Further study is needed to identify whether these alterations in the hip and knee muscles contribute to injury in athletes.

Knee Surgery Is Associated With Greater Odds of Knee Osteoarthritis Diagnosis.

CONTEXT: Knee osteoarthritis (OA) frequently develops following knee injury/surgery. It is accepted that knee injury/surgery precipitates OA with previous studies examining this link in terms of years after injury/surgery. However, postinjury OA prevalence has not been examined by decade of life; thereby, limiting our understanding of the age at which patients are diagnosed with posttraumatic knee OA. OBJECTIVE: Evaluate the association between the knee injury and/or surgical history, present age, and history of receiving a diagnosis of knee OA. DESIGN: Cross-sectional survey. SETTING: Online survey. PARTICIPANTS: A total of 3660 adults were recruited through ResearchMatch©. Of these, 1723 (47.1%) were included for analysis due to history of (1) knee surgery (SURG: n = 276; age = 53.8 [15.3] y; and body mass index [BMI] = 29.9 [8.0] kg/m2), (2) nonsurgical knee injury (INJ: n = 449; age = 46.0 [15.6] y; and BMI = 27.5 [6.9] kg/m2), or (3) no knee injury (CTRL: n = 998; age = 44.0 [25.2] y; and BMI = 26.9 [6.6] kg/m2). Respondents were subdivided by decade of life (20-29 through 70+). INTERVENTION: An electronic survey regarding knee injury history, treatment, and diagnosis of knee OA. MAIN OUTCOME MEASURES: Binary logistic regression determined the association between knee surgical status and OA by decade of life. Participants with no histories of OA or lower-extremity injury were the referent categories. BMI was a covariate in all analyses. RESULTS: SURG respondents were more likely to report having knee OA than CTRL for all age groups (odds ratios: 11.43-53.03; P < .001). INJ respondents aged 30 years and older were more likely to have OA than CTRL (odds ratios: 2.99-14.22; P < .04). BMI influenced associations for respondents in their 50s (P = .001) and 60s (P < .001) only. CONCLUSIONS: INJ increased the odds of reporting a physician diagnosis of knee OA in adults as young as 30 to 39 years. Importantly, SURG yielded 3 to 4 times greater odds of being diagnosed with knee OA compared with INJ in adults as young as 20 to 29 years. Delaying disease onset in these young adults is imperative to optimize the quality of life long term after surgery.

Females Decrease Vertical Ground Reaction Forces Following 4-Week Jump-Landing Feedback Intervention Without Negative Affect on Vertical Jump Performance.

CONTEXT: High vertical ground reaction force (vGRF) when initiating ground contact during jump landing is one biomechanical factor that may increase risk of anterior cruciate ligament injury. Intervention programs have been developed to decrease vGRF to reduce injury risk, yet generating high forces is still critical for performing dynamic activities such as a vertical jump task. OBJECTIVE: To evaluate if a jump-landing feedback intervention, cueing a decrease in vGRF, would impair vertical jump performance in a separate task (Vertmax). DESIGN: Randomized controlled trial. Patients (or Other Participants): Forty-eight recreationally active females (feedback: n = 31; 19.63 [1.54] y, 1.6 [0.08] cm, 58.13 [7.84] kg and control: n = 15; 19.6 [1.68] y, 1.64 [0.05] cm, 60.11 [8.36] kg) participated in this study. INTERVENTION: Peak vGRF during a jump landing and Vertmax were recorded at baseline and 4 weeks post. The feedback group participated in 12 sessions over the 4-week period consisting of feedback provided for 6 sets of 6 jumps off a 30-cm box. The control group was instructed to return to the lab 28 days following the baseline measurements. MAIN OUTCOME MEASURES: Change scores (postbaseline) were calculated for peak vGRF and Vertmax. Group differences were evaluated for peak vGRF and Vertmax using a Mann-Whitney U test (P < .05). RESULTS: There were no significant differences between groups at baseline (P > .05). The feedback group (-0.5 [0.3] N/kg) demonstrated a greater decrease in vGRF compared with the control group (0.01 [0.3] N/kg) (t(46) = -5.52, P < .001). There were no significant differences in change in Vertmax between groups (feedback = 0.9 [2.2] cm, control = 0.06 [2.1] cm; t(46) = 0.46, P = .64). CONCLUSIONS: While the feedback intervention was effective in decreasing vGRF when landing from a jump, these participants did not demonstrate changes in vertical jump performance when assessed during a different task. Practitioners should consider implementing feedback intervention programs to reduce peak vGRF, without worry of diminished vertical jump performance.

Evaluation of Agreement Between Participant and Expert on Jump-Landing Characteristics During a 4-Week Intervention.

CONTEXT: Feedback is an important factor in interventions designed to reduce anterior cruciate ligament injury risk. Self-analysis feedback requires participants to self-critique their jump-landing mechanics; however, it is unknown if individuals can effectively self-analyze their own biomechanics and if this self-analysis agrees with observed biomechanical changes by an expert. OBJECTIVE: To determine agreement between an expert and participants on biomechanical errors committed during 3 of 12 sessions, which were part of an intervention to change jump-landing biomechanics in healthy females. DESIGN: Descriptive analysis. SETTING: Research laboratory. PATIENTS OR OTHER PARTICIPANTS: Healthy recreationally active females with no history of lower-extremity fracture or surgery. INTERVENTIONS: Participants completed a 4-week, 12-session feedback intervention. Each intervention session lasted approximately 15 minutes and included asking participants to perform 6 sets of 6 jumps off a 30-cm-high box placed 50% of their height away from the target landing area. Participants performed self-analysis feedback and received expert feedback on 7 different jump-landing criteria following each set of jumps. MAIN OUTCOME MEASURES: Data were coded, and agreement between the expert and the participant was assessed using Cohen's unweighted kappa for sessions 1, 6, and 12. RESULTS: There was agreement between the expert and participants for 0/7 criteria for session 1, 3/7 criteria for session 6, and 4/7 criteria for session 12. CONCLUSIONS: Participants demonstrated some agreement with the expert when evaluating their jump-landing biomechanics. Self-analysis feedback may not replace what an expert can provide; both types of feedback may be better used in conjunction to produce significant biomechanical changes. Changes made by the participant may not translate into biomechanical changes during a real-life game or practice situation. Future research should continue to investigate effective interventions to reduce injury risk.

Agreement Between Investigators Using Paired-Pulse Transcranial Magnetic Stimulation to Assess Quadriceps Intracortical Excitability.

CONTEXT: Transcranial magnetic stimulation (TMS) may provide important information regarding the corticospinal mechanisms that may contribute to the neuromuscular activation impairments. Paired-pulse TMS testing is a reliable method for measuring intracortical facilitation and inhibition; however, little evidence exists regarding agreement of these measures in the quadriceps. OBJECTIVE: To determine the between-session and inter-rater agreement of intracortical excitability (short and long interval intracortical inhibition [SICI; LICI] and intracortical facilitation [ICF]) in the dominant limb quadriceps. DESIGN: Reliability study. SETTING: Research laboratory. PARTICIPANTS: Thirteen healthy volunteers (n=6 female; age: 24.7±2.1 years; height: 1.7±0.1m; mass: 77.1±17.4kg). INTERVENTION: Participants completed 2 TMS sessions separated by 1 week. MAIN OUTCOME MEASURES: Two investigators measured quadriceps SICI, LICI, and ICF at rest and actively (5% of maximal voluntary isometric contraction). All participants were seated in a dynamometer with the knee flexed to 90°. Intracortical excitability paradigm and investigator order were randomized. Bland-Altman analyses were used to establish agreement. RESULTS: Agreement was stronger between sessions within a single investigator than between investigators and for active compared to resting measures. Agreement was strongest for resting SICI and active ICF and LICI between sessions for each investigator. CONCLUSIONS: Quadriceps intracortical excitability may be measured longitudinally by a single investigator, though active muscle contraction should be elicited during testing.

Corticospinal and intracortical excitability of the quadriceps in patients with knee osteoarthritis.

Deficits in voluntary activation of the quadriceps muscle are characteristic of knee osteoarthritis (OA), contributing to the quadriceps weakness that is also a hallmark of the disease. The mechanisms underlying this central activation deficit (CAD) are unknown, although cortical mechanisms may be involved. Here, we utilize transcranial magnetic stimulation (TMS) to assess corticospinal and intracortical excitability in patients with knee OA and in a comparably aged group of healthy older adults, to quantify group differences, and to examine associations between TMS measures and pain, quadriceps strength, and CAD. Seventeen patients with knee OA and 20 healthy controls completed testing. Motor evoked potentials were measured at the quadriceps by superficial electromyographic recordings. Corticospinal excitability was assessed by measuring resting motor threshold (RMT) to TMS stimulation of the quadriceps representation at primary motor cortex, and intracortical excitability was assessed via paired-pulse paradigms for short-interval intracortical inhibition (SICI) and intracortical facilitation (ICF). No statistically significant differences between patients with knee OA and healthy controls were found for RMT, SICI or ICF measures (p > 0.05). For patients with knee OA, there were significant associations observed between pain and RMT, as well as between pain and ICF. No associations were observed between CAD and measures of corticospinal or intracortical excitability. These data suggest against direct involvement of corticospinal or intracortical pathways within primary motor cortex in the mechanisms of CAD. However, pain is implicated in the neural mechanisms of quadriceps motor control in patients with knee OA.

Muscle strength and functional recovery during the first year after THA.

BACKGROUND: Patients undergoing total hip arthroplasty (THA) often are satisfied with the decrease in pain and improvement in function they achieve after surgery. Even so, strength and functional performance deficits persist after recovery, but these remain poorly characterized; knowledge about any ongoing strength or functional deficits may allow therapists to design rehabilitation programs to optimize recovery after THA. QUESTIONS/PURPOSES: The purposes of this study were to (1) evaluate postoperative muscle strength, function, and quality of life during the first year after THA; and (2) compare strength and function in patients 1 year after THA with a cohort of healthy peers. METHODS: Twenty-six patients undergoing THA were assessed 1, 3, 6, and 12 months postoperatively, and 19 adults with no hip pathology were tested as a control group. Isometric muscle strength (hip flexors, extensors, abductors, knee extensors, and flexors), functional performance (stair climbing, five times sit-to-stand, timed-up-and-go, 6-minute walk, and single-limb stance tests), and self-reported function (Hip Disability and Osteoarthritis Score, SF-36, and UCLA activity score) were compared. RESULTS: One month after THA, patients had 15% less hip flexor and extensor torque, 26% less abductor torque, 14% less knee extensor and flexor torque, and worse performance on the stair climbing, timed-up-and-go, single-limb stance, and 6-minute walk. Compared with healthy adults, patients 12 months after THA had 17% less knee extensor and 23% less knee flexor torque; however, the functional testing (including stair climbing, five times sit-to-stand, and the 6-minute walk) showed no significant differences with the patient numbers available between individuals undergoing THA and healthy control subjects. SF-36 Physical Component Scores, although significantly improved from preoperative levels, were significantly worse than healthy adults 1 year after THA (p < 0.01). CONCLUSIONS: Patients experience early postoperative strength losses and decreased functional capacity after THA, yet strength deficits may persist after recovery. This may suggest that rehabilitation may be most effective in the first month after surgery.

Fatigue's lack of effect on thigh-muscle activity in anterior cruciate ligament-reconstructed patients during a dynamic-landing task.

CONTEXT: As individuals returning to activity after anterior cruciate ligament reconstruction (ACLr) likely experience fatigue, understanding how fatigue affects knee-muscle activation patterns during sport-like maneuvers is of clinical importance. Fatigue has been suggested to impair neuromuscular control strategies. As a result, fatigue may place ACLr patients at increased risk of developing posttraumatic osteoarthritis (OA). OBJECTIVE: To determine the effects of fatigue on knee-muscle activity post-ACLr. DESIGN: Case control. SETTING: University laboratory. PARTICIPANTS: 12 individuals 7-10 mo post-ACLr (7 male, 5 female; age 22.1 ± 4.7 y; 1.8 ± 0.1 m; mass 77.7 ± 11.9 kg) and 13 controls (4 male, 9 female; age 22.9 ± 4.3 y; 1.7 ± 0.1 m; mass 66.9 ± 9.8 kg). INTERVENTIONS: Fatigue was induced via repetitive sets of double-leg squats (n = 8), which were interspersed with sets of single-leg landings (n = 3), until squats were no longer possible. MAIN OUTCOME MEASURES: 2 × 2 repeated-measures ANOVA was used to detect the main effects of group (ACLr, control) and fatigue state (prefatigue, postfatigue) on quadriceps:hamstring cocontraction index (Q:H CCI). RESULTS: All subjects demonstrated higher Q:H CCI at prefatigue compared with postfatigue (F(1,23) = 66.949, P ≤ .001). Q:H CCI did not differ between groups (F(1,23) = 0.599, P = .447). CONCLUSIONS: The results indicate that regardless of fatigue state, ACLr individuals are capable of restoring muscle-activation patterns similar to those in healthy subjects. As a result, excessive muscle cocontraction, which has been hypothesized as a potential mechanism of posttraumatic OA, may not contribute to joint degeneration after ACLr.

Exercise-Induced Changes in Femoral Cartilage Thickness in Patients With Patellofemoral Pain.

CONTEXT: Rehabilitative exercises alleviate pain in patients with patellofemoral pain (PFP); however, no researchers have analyzed the cartilage response after a bout of those athletic activities in patients with PFP. OBJECTIVE: To determine if a single session of rehabilitative exercises alters femoral cartilage morphology. DESIGN: Crossover study. SETTING: Research laboratory. PATIENTS OR OTHER PARTICIPANTS: Twelve participants with PFP (age = 21.0 ± 2.0 years, height = 1.72 ± 0.1 m, mass = 68.7 ± 12.6 kg) and 12 matched healthy participants (age = 21.3 ± 2.8 years, height = 1.71 ± 0.1 m, mass = 65.9 ± 12.2 kg) were enrolled. INTERVENTION(S): Participants completed treadmill running, lower extremity strengthening exercises, and plyometric exercises for 30 minutes each. MAIN OUTCOME MEASURE(S): Patient-reported outcomes on the visual analog scale, Anterior Knee Pain Scale (AKPS), Knee injury and Osteoarthritis Outcome Score (KOOS), and Knee Injury and Osteoarthritis Outcome Score for Patellofemoral Pain and Osteoarthritis were collected. Femoral cartilage ultrasonographic images were obtained at 140° of knee flexion. Ultrasound images were segmented into medial and lateral images using the intercondylar notch. Medial and lateral cartilage cross-sectional area (mm2) and echo intensity (EI), defined as the average grayscale from 0 to 255, were analyzed by ImageJ software. The difference between loading conditions was calculated using repeated-measures analysis of variance. The Spearman correlation was calculated to find the association between the cartilage percentage change (Δ%) and patient-reported outcomes. RESULTS: Pain increased in the PFP group after all loading conditions (P values < .007). No differences were found in cartilage cross-sectional area or EI alteration between or within groups (P values > .06). The KOOS was negatively associated with the Δ% of the lateral femoral cartilage EI after plyometric loading (ρ = -0.87, P = .001), and the AKPS score was positively correlated with the Δ% of lateral femoral cartilage EI (ρ = 0.57, P = .05). CONCLUSIONS: Ultrasound imaging did not identify cartilaginous deformation after all loading conditions. However, because lateral cartilaginous EI changes were associated with the AKPS and KOOS score, those questionnaires may be useful for monitoring changes in femoral cartilage health.

Lower limb muscle activation pattern in male soccer players with lumbar hyperlordosis.

OBJECTIVE: the aim of the current study was to compare the lower limb muscle activation pattern in soccer players with and without lumbar hyperlordosis during single-leg squat performance. METHODS: thirty male collegiate soccer players (15 with and 15 without lumbar hyperlordosis) performed the SLS task. Surface EMG was used to record the activation of eleven lower limb muscles. The activation of these muscles reduces to 100 points during the SLS cycle, where 50% demonstrates the maximum knee flexion, and 0% and 99% demonstrate the maximum knee extension. RESULTS: soccer players with lumbar hyperlordosis had higher muscle activation than those with normal lumbar lordosis in gluteus maximus, biceps femoris, and medial gastrocnemius. By contrast, they had lower gluteus medius, vastus medialis oblique, rectus femoris, soleus, and medial gastrocnemius (only in the final ascent phase of the SLS) muscle activity than the normal group during the SLS. CONCLUSION: this alteration may negatively affect targeted muscle performance during the SLS. Subsequent study is required to specify whether such an alteration in the lower limb muscle could be accompanied by injury in soccer players and change in their athletic performance.

Within-session and between-session effects of auditory biofeedback training on center of pressure location during gait in patients with chronic ankle instability.

OBJECTIVES: To establish preliminary gait training dosage parameters for patients with chronic ankle instability (CAI) by determining the within-session and between-session effects of auditory biofeedback training on center of pressure (COP) location during gait. DESIGN: Observational Longitudinal. SETTING: Laboratory. PARTICIPANTS: 19 participants with CAI, 8 participants who did not receive auditory biofeedback (NoFeedback group) and 11 participants who did receive auditory biofeedback (AuditoryFeedback group) over an 8-session 2-week intervention. MAIN OUTCOME MEASURES: COP location was measured at the start and at each 5-min interval during treadmill walking across all eight 30-min training sessions. RESULTS: The AuditoryFeedback group had significant within-session lateral-to-medial shifts in COP location during only session-1 at the 15-min (45% of stance; peak mean difference = 4.6 mm), 20-min (35% and 45%; 4.2 mm), and 30-min time intervals (35% and 45%; 4.1 mm). Furthermore, the AuditoryFeedback group had significant between-session lateral-to-medial shifts in COP location at session-5 (35-55% of stance; 4.2 mm), session-7 (35%-95%; 6.7 mm), and session-8 (35%-95%; 7.7 mm). The NoFeedback group had no significant changes in COP location within-sessions or between-sessions. CONCLUSIONS: Participants with CAI who received auditory biofeedback during gait needed an average of 15-min during session-1 to meaningfully shift their COP location medially and 4-sessions before retaining the adapted gait pattern.

The challenge point framework to improve stepping reaction and balance in children with hemiplegic cerebral palsy: A case series study.

PURPOSE: This study investigated the effects of the challenge point framework (CPF) to improve stepping reactions and enhance balance in children with hemiplegic cerebral palsy (HCP). The CPF relates practice variables to the skill level of the individual and task difficulty. METHODS: Nine children with HCP (age: 7.7±2.4 years) completed six weeks (12 sessions) of a CPF intervention which consisted of progressively fewer sets and repetitions of a stepping reaction task wherein participants sought to improve both step length and reaction rate. Stepping reaction (step length and reaction rate) to a balance perturbation in the anterior, posterior, and lateral directions and static and dynamic balance (via the Pediatric Balance Scale) were measured at baseline, a second baseline 3 weeks later, and post-intervention. Repeated measures ANOVAs determined within-group changes. Cohen's d effect sizes were calculated. RESULTS: Participants improved balance (d = 0.948, p = 0.010), step length (forward d = 0.938, p = 0.002; backward d = 0.839, p = 0.001; and lateral d = 0.876, p = 0.002), and reaction rate (forward d = 0.249, p = 0.042; backward d = 0.21, p = 0.047; and lateral d = 0.198, p = 0.049). CONCLUSION: These findings indicate that children with HCP may benefit from completing a CPF program with a motor learning approach. This approach of retraining stepping reactions helped to improve static and dynamic balance. The CPF may aid progression of functional task training in children with HCP aged 4-12, though more studies with a long-term follow-up analysis are needed to confirm this result.

Comparing kinematic asymmetry and lateral step-down test scores in healthy, chronic ankle instability, and patellofemoral pain syndrome female basketball players: a cross-sectional study.

We aimed to understand whether ankle dorsiflexion range of motion (ROM) and dynamic knee valgus (DKV) kinematic inter-limb asymmetries would be associated with the Lateral Step-Down Test (LSD) in basketball players with chronic ankle instability (CAI), patellofemoral pain (PFP) and healthy controls (HC). An observational cross-sectional study with a between-subject design was employed. Female basketball athletes with CAI (n = 20), PFP (n = 20) and HC (n = 20) were recruited. Ankle dorsiflexion-ROM, DKV angle during a single-limb squat, and LSD quality were measured bilaterally. The Asymmetry index (ASI) was calculated to identify between-limb percentage imbalances. The correlation matrix between the tasks was calculated. Ankle dorsiflexion-ROM was less in the CAI and PFP than in the HC group regardless of limb (p < 0.001). DKV angle was greater in the CAI and PFP than in the HC group bilaterally (p < 0.001). LSDs were similar between the PFP and CAI groups (p = 0.698) but worse than the HC group (p = 0.001). The ASI showed asymmetry across all tasks (p < 0.001), with the greatest asymmetry for the DKV angle. The correlation matrix between tasks on both limbs was significant (p < 0.05). Our findings suggest significant asymmetries in ankle dorsiflexion-ROM and frontal plane knee control are present in female basketball athletes with CAI and PFP, and thus, highlights need to evaluate and reduce limb asymmetries in these populations.

Importance of attenuating quadriceps activation deficits after total knee arthroplasty.

Total knee arthroplasty (TKA) is associated with persistent quadriceps dysfunction. Because quadriceps dysfunction impairs functional performance, minimizing quadriceps dysfunction by attenuating central activation deficits early after surgery may improve function later in life. Rehabilitation strategies incorporating neuromuscular electrical stimulation and early, aggressive quadriceps strengthening may prove beneficial. Furthermore, surgical approaches, such as minimally invasive TKA, may minimize postoperative quadriceps dysfunction.

The effect of time-of-day and sleep deprivation on postural control: A systematic review.

BACKGROUND: Postural control (PC) can be affected by circadian rhythm and sleep deprivation, whereby it has been reported the result of PC measurement in clinical and experimental situations can be influenced by both factors. It has been suggested sleepiness can result in deficiency in PC, which in turn can lead to occupational accidents and subsequent injuries. This is while no study critically reviews or summarizes findings surrounding this topic in the literature. RESEARCH QUESTION: Is there any significant effect of sleep deprivation and circadian rhythm on PC variables among healthy individuals? METHODS: PubMed, Web of Science, Scopus, and Embase were used to detect relevant studies. Only studies that examined the effect of time of day and/or sleep loss on PC among healthy individuals were included in this systematic review. RESULTS: Forty-nine studies were included based on the inclusion criteria. Both circadian rhythm and sleep loss had a significant effect on PC, whereas there are inconsistent findings for optimal postural control regarding time of day. In terms of sleep deprivation, all investigations indicated that sleep loss deteriorates PC. SIGNIFICANCE: The current systematic review represents a significant effect of circadian rhythm and sleep deprivation on PC, whereby it is suggested that clinicians and researchers consider these factors when measuring PC since it may affect the result of research and clinical test. Moreover, PC may be worsened through sleeplessness; however, some studies revealed there is no linear relationship between time of wakefulness and deteriorating PC due to the influence of circadian rhythm. Hence, while PC, as an objective tool, can help to detect those who are sleep deprived, which in turn can lead to prevent possible musculoskeletal injuries, further studies are needed to reveal more understanding about the effect of sleep loss and circadian rhythm on PC.

Effects of gait training with auditory biofeedback on biomechanics and talar cartilage characteristics in individuals with chronic ankle instability: A randomized controlled trial.

BACKGROUND: Altered walking gait is a typical impairment following ankle sprains which may increase susceptibility to recurring injuries and development of posttraumatic osteoarthritis at the ankle. There is a lack of targeted gait training interventions focusing on specific modifications in individuals with chronic ankle instability (CAI). Additionally, there is a need to focus on cartilage health changes following gait training to mitigate osteoarthritis progression. RESEARCH QUESTION: To determine the immediate and retention effects of gait training using auditory biofeedback (AudFB) in patients with chronic ankle instability (CAI) on biomechanics and talar cartilage characteristics. METHODS: Eighteen participants with CAI were randomly assigned into Control (n = 7) or AudFB (n = 11) groups. Each group completed 8-sessions of 30-minute treadmill walking. The AudFB group received biofeedback through a pressure sensor fashioned to the lateral foot and instructions to walk while avoiding noise from the sensor. The Control group did not receive instructions during sessions. An in-shoe insole system measured peak pressure, maximum force, and center of the pressure gait line (COP) during walking. Ultrasonography captured talar cartilage thickness and echo intensity before and after walking. Biomechanics and ultrasound were measured at baseline, immediately, and 1-week after the intervention. Repeated measures mixed-methods analysis of variance assessed changes within groups across time. RESULTS: The AudFB group significantly reduced pressure and force in the lateral foot and medially shifted their COP at Immediate and 1-week Post. There were no observed changes in the Control group. In addition, neither group demonstrated changes in ultrasound measures at follow-up. SIGNIFICANCE: Implementation of auditory biofeedback during gait training can be a valuable tool for clinicians treating patients with CAI.

Plantar pressure profile during walking is associated with talar cartilage characteristics in individuals with chronic ankle instability.

BACKGROUND: Individuals with chronic ankle instability typically present with abnormal gait patterns favoring the lateral foot. This gait pattern may alter cartilage stress potentially increasing the risk of osteoarthritis development, thus exploring this relationship may provide insights for early interventions. The purpose of this study was to examine the relationship gait biomechanics and talar articular cartilage characteristics. METHODS: Talar articular cartilage was assessed with ultrasound at rest and after walking for 30-min in twenty-five adults (14 females, 22.6 ± 3.12 years, 168.12 ± 9.83 cm, 76.00 ± 15.47 kg) with chronic ankle instability. Cartilage was segmented into Total, Medial, and Lateral regions. During the 30-min walking period, plantar pressure of the entire foot was recorded every 5-min and condensed to create a biomechanical loading pattern and center of pressure gait line. Relationships between resting cartilage thickness and echo intensity, changes in thickness and echo intensity, and plantar pressure profiles were assessed with correlation coefficients. FINDINGS: There was a significant relationship between plantar pressure in the lateral forefoot and medial talar cartilage deformation (r = 0.408, p < .05). Early stance center of pressure was correlated with deformation in the total (r = 0.439-0.524) and lateral (r = 0.443-0.550) regions (p < .05). There were no significant correlations between echo intensity and biomechanics. INTERPRETATION: This study contributes to the growing evidence that talar cartilage strain patterns are associated with biomechanics during walking. Further validation is needed to determine a causal relationship between biomechanics and ultrasound cartilage characteristics after ankle sprains. In addition, research should continue determining the utility of ultrasound to monitor joint health after musculoskeletal injuries.

Inter-limb asymmetry of kinetic and electromyographic during walking in patients with chronic ankle instability.

After an initial ankle sprain, a relevant number of participants develop chronic ankle instability (CAI). Compensatory strategies in patients with CAI may change the inter-limb symmetry needed for absorbing movement-related forces. Accordingly, an increased risk of injury can occur. The present study aimed to compare the inter-limb asymmetry of kinetic and electromyography between individuals with CAI and without a history of an ankle sprain (Non-CAI) during walking. In this cross-sectional study, fifty-six athletes (28 CAI; 28 Non-CAI) participated. Participants walked at a comfortable pace over level ground while vertical ground reaction force (vGRF) and muscle activity of the tibialis anterior, peroneus longus, medial gastrocnemius, and gluteus medius were recorded. Inter-limb asymmetry during walking was calculated for each of the variables. Patients with CAI exhibited a greater inter-limb asymmetry of the first peak of vGRF, time to peak vGRF, and loading rate (P < 0.001), as well as presenting a greater inter-limb asymmetry of peroneus longus activity (contact phase) (P = 0.003) and gluteus medius activity (midstance/propulsion phase) (P = 0.010) compared to the Non-CAI group. No other differences in vGRF or muscles activity were observed between the groups. Our findings indicate that patients with CAI walk with greater inter-limb asymmetry in vGRF and muscle activity in different phases of the gait cycle compared to Non-CAI group. Our results could inform future studies on gait training aimed to reduce asymmetry during walking in patients with CAI.

Multi-axis destabilisation device influences plantar pressure distribution in adults with chronic ankle instability.

Patients with chronic ankle instability (CAI) walk with increased lateral plantar pressure, precipitating future injuries. Gait retraining to medially shift plantar pressure may prevent recurrent injury. We assessed if a multi-axis destabilisation device changed plantar pressure and muscle activity in patients with CAI during walking. Twelve adults with CAI (age: 23.6 ± 5.0 years; body mass index: 26.7 ± 4.5 kg/m2) participated. Insole plantar pressure and electro-myography were collected synchronously during treadmill walking. The destabilisation device had a half-sphere under both the rearfoot and forefoot. Two 30s walking trials were recorded at baseline, first without and second with the destabilisation device. After 20 min of walking with the destabilisation device, two 30s post-walking trials were collected, first with and second without the destabilisation device. The middle 10 steps of each trial were extracted, plantar pressure quantified, and data averaged across steps for repeated measures ANOVA analysis. Electromyographic data wereextracted from 50 ms pre- through 200 ms post-initial contact. The centre of pressure shifted medially during destabilisation device use (P < 0.002) versus baseline. This shift was notretained upon device removal. Thus, the device capably shifts plantar pressure while worn. Its effects beyond a single sessionare unknown.