Anticipation of landing leg masks ankle inversion orientation deficits and peroneal insufficiency during jump landing in people with chronic ankle instability.

Ankle inversion orientation and peroneal activation insufficiency may contribute to lateral ankle sprains during landing in chronic ankle instability (CAI); however, how anticipation alters these factors is neglected. This study aimed to assess the impact of anticipation on joint orientation and muscle activity during landing in individuals with CAI. Fifteen participants with CAI and 15 healthy participants (control) were recruited to perform single-leg landings after bilateral countermovement jumps when the landing limb was specified before (planned) or after (unplanned) take-off. Joint angle (hip, knee, and ankle) and electromyography (gluteus medius, rectus femoris, biceps femoris, gastrocnemius lateral head, tibialis anterior, and peroneal longus) were collected and analyzed with 2 (groups) × 2 (conditions) statistical parametric mapping ANOVA. In the unplanned condition, the CAI group demonstrated a less plantarflexed (maximum difference [MD] = 9.5°, p = 0.047) and more inverted ankle joint (MD = 4.1°, p < 0.001) before ground contact, along with lower peroneal activity at ground contact compared to the control group (MD = 28.9% of peak activation, p < 0.001). No significant differences between groups were observed in the planned condition. In conclusion, anticipation may mask jump landing deficits in people with CAI, including inverted ankle orientation and reduced peroneus longus activity pre- and post-landing, which were observed exclusively in unplanned landings. Clinicians and researchers need to recognize the impact of anticipation on apparent landing deficits and consider the implications for injury prevention and rehabilitation strategies.

Evidence for a new model of the complex interrelationship of ball possession, physical intensity and performance in elite soccer.

BACKGROUND: How the physical metrics, especially physical intensity, and possession interact with each other, and subsequently combine to influence performance remains opaque. Therefore, we investigated the interrelationship of possession, physical metrics, and team performance in elite soccer. METHODS: Four seasons of a top European league were used to derive 80 team league performances (points), together with possession and physical data. Physical metrics were absolute distances (m) during the whole match and ball-in-play, and rates of distance covered (m⋅min-1 ) as the index of physical intensity, notably when in-possession/out-of-possession, in total and within five speed categories. Interrelationships of possession, physical metrics, possession, and performance were assessed with Pearson's correlations and mediation analysis. RESULTS: Overall possession (r = 0.794) and time out-of-possession within the defensive third (r = -0.797) were most strongly correlated with performance. The strong relationships between in-possession distances and performance appeared coincidental due to greater time in-possession. Physical intensity had a complex relationship with possession and performance, with opposite relationships according to possession status: lower physical intensity when in-possession and higher physical intensity when out-of-possession were associated with possession and performance. Mediation analysis revealed the direct, independent importance of possession for team performance; however, the association of physical intensity with performance was largely (>79%) mediated by possession. CONCLUSION: Based on these findings, we propose a novel model of the interrelationships between possession, physical intensity, and performance, whereby higher possession is the largest, direct contributor toward enhanced team performance, with lower physical intensity in-possession a consequence of higher possession, but greater physical intensity when out-of-possession a cause of increased possession.

Enhancing running injury prevention strategies with real-time biofeedback: A systematic review and meta-analysis.

The number of runners and the incidence of running-related injuries (RRIs) are on the rise. Real-time biofeedback gait retraining offers a promising approach to RRIs prevention. However, due to the diversity in study designs and reported outcomes, there remains uncertainty regarding the efficacy of different forms of feedback on running gait biomechanics. Three databases: MEDLINE, PUBMED, and SPORTDiscus were searched to identify relevant studies published up to March 2024, yielding 4646 articles for review. The quality of the included studies was assessed using the Downs and Black Quality checklist. Primary outcomes, including Peak Tibial Acceleration (PTA), Vertical Average Loading Rate (VALR), and Vertical Instantaneous Loading Rate (VILR), were analysed through meta-analysis. 24 studies met the inclusion criteria and were analysed in this review.17 used visual biofeedback (VB) while 14 chose auditory biofeedback (AB). The meta-analysis revealed a reduction in loading variables both immediately following the intervention and after extended training, with both visual and auditory feedback. Notably, the decrease in loading variables was more pronounced post-training and VB proved to be more effective than AB. Real-time biofeedback interventions are effective in lowering loading variables associated with RRIs. The impact is more substantial with sustained training, and VB outperforms AB in terms of effectiveness.

Effects of Gluteus Medius and Biceps Femoris Stimulation on Reduction of Knee Abduction Moment During a Landing Task.

Anterior cruciate ligament injury prevention should focus primarily on reduction of the knee abduction moment (KAM) in landing tasks. Gluteus medius and hamstring forces are considered to decrease KAM during landing. The effects of different muscle stimulations on KAM reduction were compared using 2 electrode sizes (standard 38 cm2 and half size 19 cm2) during a landing task. Twelve young healthy female adults (22.3 [3.6] y, 1.62 [0.02] m, 50.2 [4.7] kg) were recruited. KAM was calculated under 3 conditions of muscle stimulation (gluteus medius, biceps femoris, and both gluteus medius, and biceps femoris) using 2 electrode sizes, respectively versus no stimulation during a landing task. A repeated-measures analysis of variance determined that KAM differed significantly among stimulation conditions and post hoc analysis revealed that KAM was significantly decreased in conditions of stimulating either the gluteus medius (P < .001) or the biceps femoris (P < .001) with the standard electrode size, and condition of stimulating both gluteus medius and biceps femoris with half-size electrode (P = .012) when compared with the control condition. Therefore, stimulation on the gluteus medius, the biceps femoris, or both muscles could be implemented for the examination of anterior cruciate ligament injury potential.

Muscle co-contraction and pre-activation in knee and ankle joint during a typical Tai Chi brush-knee twist-step.

This study aimed to investigate the co-contraction and pre-activation of agonistic and antagonistic muscles in experienced Tai Chi (TC) practitioners during normal walking (NW) and brush-knee twist-step (BKTS). The electromyographic activities of rectus femoris, biceps femoris, and tibialis anterior and lateral gastrocnemius muscles were collected during BKTS and NW in 28 TC practitioners. The pre-activation of knee and ankle joints before initial landing of left foot, and the co-contraction of knee and ankle joint in double-stance phase I (DSI), single-stance phase (SS), double-stance phase II (DSII), and swing phase (SW) were calculated during BKTS and NW. Ankle co-contraction significantly increased during DSI and SS in BKTS movements than compared with that in NW. For DSI and SW, SS and DSII, and DSII and SW, a significant difference was found in BKTS. The pre-activation of knee joint significantly decreased in BKTS and NW. This study indicated greater ankle joint muscle co-contraction in DSI and SS of stance phase and lower knee joint muscle co-contraction and pre-activation than in NW in BKTS movement. In addition, greater ankle joint muscle co-contraction was observed in the DSI, SS, and DSII of stance phase than those of swing phase in BKTS movement.

Bilateral impairments of quadriceps neuromuscular function occur early after anterior cruciate ligament injury.

The study aimed to investigate the impairments in quadriceps neuromuscular function, including strength, rate of torque development (RTD) and activation failure (QAF) early after an ACL injury. A cross-sectional study was conducted. Thirty physically active patients with a primary ACL injury within three months, aged 18 to 40 years old, and who were scheduled for ACL reconstruction were included. Thirty matched healthy controls were also recruited. All the outcomes were measured on an isokinetic dynamometer with knee flexion at 45°. Quadriceps strength was measured by maximal voluntary isometric contractions (MVIC). Early (RTD0-50) and late (RTD100-200) phases of RTD were retrieved from the MVIC test from 0 to 50 ms and 100-200 ms, respectively. QAF was quantified by the central activation ratio (CAR) measured by superimposed burst technique. The results of Mann-Whitney U test showed that compared with the healthy limbs, the injured limbs of the ACL group showed lower quadriceps strength (P < 0.001), RTD0-50 (P < 0.001) and RTD100-200 (P < 0.001); the uninjured limbs showed lower quadriceps strength (P = 0.009), RTD0-50 (P = 0.006) as well as greater QAF (P = 0.010). To conclude, bilateral quadriceps suffered from neuromuscular impairments early after an ACL injury.

Associations of patient characteristics, rate of torque development, voluntary activation of quadriceps with quadriceps strength, and knee function before anterior cruciate ligament reconstruction.

Good preoperative knee function (KF) and quadriceps strength (QS) relate to good prognoses after anterior cruciate ligament reconstruction (ACLR). This study aimed to investigate the associations between patient characteristics, rate of torque development (RTD), voluntary activation (VA) of the quadriceps against preoperative KF and QS. A cross-sectional study was conducted. Forty patients with a primary, unilateral ACL injury who had finished the preoperative rehabilitation and scheduled for an ACLR were included. KF was evaluated using the International Knee Documentation Committee score. QS was measured by maximal voluntary isometric contractions. RTD was divided into the early (RTD0-50) and the late (RTD100-200) phases. Quadriceps VA was measured using the superimposed burst technique. Our results showed that patients with poor preoperative KF had more deficits in RTD0-50 (P = 0.025), higher BMI(P = 0.043), and more meniscus injuries (MI) (P = 0.001) than those with good KF. Patients with asymmetrical QS showed lower BMI (P = 0.020) and shorter time from injury (TFI) (P = 0.027) than those with symmetrical QS. Additionally, a higher pre-injury Tegner score combined with greater RTD100-200 contributed to greater QS on the injured limb (R2 = 0.357, P = 0.001). To conclude, BMI, TFI, concomitant MI, pre-injury physical activity level, and quadriceps RTD are related to QS and KF before ACLR.

Knee wobbling during the single-leg-squat-and-hold test reflects dynamic knee instability in patients with anterior cruciate ligament injury.

We propose using the single-leg squat-and-hold (SLSH) task with kinematic analysis to objectively measure dynamic knee stability after anterior cruciate ligament (ACL) injury. There are three objectives of this study: to compare the knee kinematics of ACL-deficient patients and healthy controls by capturing knee wobbling during the SLSH task, to detect kinematic changes after ACL reconstruction, and to correlate the kinematic variables with self-reported knee function. Twenty-five ACL-deficient participants and 18 healthy matched participants were recruited. The knee kinematics involving both the magnitudes and frequency of motion fluctuation was captured during SLSH by 3D motion analysis system (Vicon). Compared to the limbs of the control participants, the ACL involved limbs exhibited a greater range of flexion-extension (4.33 ± 1.96 vs. 2.73 ± 1.15; p = 0.005) and varus-valgus (2.52 ± 0.99 vs. 1.36 ± 0.42; p < 0.001). It also inhibited higher frequency of flexion-extension (4.87 ± 2.55 vs. 2.68 ± 1.23; p = 0.003) and varus-valgus (3.83 ± 2.59 vs. 1.42 ± 0.55; p < 0.001). The range of flexion-extension (4.50 ± 2.24 vs. 2.90 ± 1.01; p = 0.018), frequency of flexion-extension (4.58 ± 2.53 vs. 3.05 ± 1.80; p = 0.038) and varus-valgus (3.46 ± 2.11 vs. 1.80 ± 1.23; p = 0.022) was reduced after ACL reconstruction. Increased frequency of knee varus-valgus was correlated with lower IKDC score (r = -0.328; p = 0.034). Knee wobbling was more prominent in ACL-deficient patients, which was associated with poor knee function. SLSH task with kinematic analysis appears to be a potential assessment method for monitoring dynamic knee stability after ACL injury.

Delayed peroneal muscle reaction time in male amateur footballers during a simulated prolonged football protocol.

Peroneal muscle fatigue could result in ankle inversion sprain injuries. This study investigated the peroneal muscle reaction time during a simulated prolonged football protocol. Nine male footballers completed a 105-minute simulated prolonged football protocol. The peroneal muscle reaction time to an ankle inversion perturbation was measured every 15 minutes by a surface electromyography system sampling at 1000 Hz. One-way repeated ANOVA with post-hoc paired t-test showed a steady upward trend starting from 48.9 ms at baseline to 57.1 ms at the end of the first half, followed by a recovery back to 50.9 ms at the start of the second half and a further delay in the last 30 minutes to 60.2 ms at the end of the protocol. Delayed peroneal muscle reaction was found after 30 minutes of the first half and 15 minutes of the second half of a football match. The risk of ankle sprain could increase in the latter minutes in each half protocol. Thus, prevention injury training strategies should focus on these specific durations in football matches.

Peroneal reaction time delayed but dynamic single-legged stability retained in collegiate footballers during a simulated prolonged football protocol.

Delayed peroneal reaction time and impaired single-legged dynamic stability were risk factors of lateral ankle sprain (LAS), yet no study explored the change of them during a football match. The aim is to explore the change of peroneal reaction time and single-legged dynamic stability during a football simulation protocol. Twelve collegiate football players voluntarily completed a 105-min football match simulation protocol in which peroneal reaction time, root-mean-square of mediolateral ground reaction force in first 0.4 s (RMS ML 0.4), and the mean mediolateral ground reaction force in the late stage (late dynamic MLGRF), were measured for both legs at 15-min intervals during the protocol. Peroneal reaction time was tested using an electromyography (EMG) system. The ground reaction force variables were measured from GRF data after a single-legged drop-jump landing. Repeated measures one-way MANOVA was conducted to evaluate variables over time and leg dominance. Statistical significance was set at p < 0.05 level. Peroneal reaction time significantly increased for both legs at 45 minutes and after 60 minutes. RMS ML 0.4 of both legs and late dynamic MLGRF for dominant leg remained unchanged throughout the protocol and late dynamic MLGRF for non-dominant leg significantly reduced at the 90th minute.

Injuries in Japanese university handball: a study among 1017 players.

The aim of this study was to examine the injury profile of Japanese university handball players. In this cross-sectional study, a total of 1017 participants who played in the 2018 Japanese National University Handball Championship were followed. The incidence within the previous year was 0.59 [95% CI, confidence interval: 0.56-0.62] per player per year. The ankle (33.3%), knee (23.6%), and shoulder/clavicle (12.6%) were the body regions most affected by traumatic mechanisms, while the lumbar spine/lower back (26.0%), knee (15.7%), and shoulder (15.0%) were the body regions most affected by overuse mechanisms. Sprain (30.7%), ligamentous rupture (23.2%), and fracture (11.8%) were the main types of traumatic injuries, and stress fracture (25.0%) and lesion of meniscus or cartilage (25.0%) were the main types of overuse injuries. Female players were 1.5 times more likely (OR, odds ratio: 1.55 [95% CI: 1.20-2.01]) to experience an injury than their male counterparts, and line players were also 1.5 times more likely (OR: 1.49 [95% CI: 1.00-2.21]) to experience an injury than their wing counterparts. This study showed that there is a need for increased injury prevention efforts in Japanese handball, especially among female players.

Screening for laterally deviated plantar pressure during stance using the Cumberland ankle instability tool and anthropometric measures.

This study developed a method that predicts laterally deviated plantar pressure during stance by lower limb anthropometrics and self-reported ability to stop an ankle which has started to roll over. Thirty-two males ran on a treadmill for 2 minutes at 11 km/h. Foot pressure data were collected by a pressure insole system for classifying the participants as medial or lateral strikers. Cumberland Ankle Instability Tool score, Tegner Activity Scale score, foot arch height, active and passive ankle and knee range of motion, bi-malleolar width, foot length, foot width and calf circumference were measured. Binary logistic regressions were performed to produce a model which estimated if an individual showed laterally deviated foot pressure during stance. The model utilized the score of Cumberland Ankle Instability Tool Question 8, active and passive knee joint external rotation, height, body mass and bimalleolar width (explained variance of 47.3%, p = 0.037), producing a sensitivity of 71.4% and a specificity of 54.5%. A validation trial on another 15 runners reported a 73.3% accuracy in prediction if they are medial or lateral strikes.

A clinically applicable tool for rapidly estimating muscle volume using ultrasound images.

PURPOSE: This study aimed to identify a safe, rapid, and accessible method of estimating muscle volume of key lower limb muscle groups to reduce the time-demand of acquiring this measurement and potentially facilitate its application as a clinical monitoring tool. METHODS: Unilateral MRI images were acquired from the 12th thoracic vertebrae to the base of the foot in 18 recreationally active males. Panoramic B-mode ultrasound images were acquired from the same leg at the mid-hip, 25%, 50%, and 75% of thigh length, and 25% of shank length. Body mass, height, limb lengths, and circumferences at the sites corresponding to the ultrasound images were acquired. A single investigator manually analysed all images. Regression analyses were conducted to identify models for estimating volume of the hip extensor, knee extensor and flexor, and ankle plantarflexor muscle groups. RESULTS: Models were developed for estimating hip extensor (SEE = 8.92%, R2 = 0.690), knee extensor (SEE = 5.24%, R2 = 0.707) and flexor (SEE = 7.89%, R2 = 0.357), and ankle plantarflexor (SEE = 10.78%, R2 = 0.387) muscle group volumes. The hip and knee extensor models showed good potential for generalisation. Systematic error was observed for the knee flexor and ankle plantarflexor models. CONCLUSIONS: Hip extensor, knee extensor and flexor, and ankle plantarflexor muscle group volumes can be estimated using B-mode ultrasound images and anthropometric measurements. The error shown for each of the models was sufficient to identify previously reported differences in muscle volume due to training or injury, supporting their clinical application.

A Systematic Review on the Effectiveness of Eyewear in Reducing the Incidence and Severity of Eye Injuries in Racket Sports.

PURPOSE: To assess what eyewear (if any) reduces eye injury incidence and severity in squash, racketball, tennis and badminton. DESIGN: Systematic review following the 'Preferred Reporting Items for Systematic Reviews and Meta-Analyses' (PRISMA) and the 'implementing Prisma in Exercise, Rehabilitation, Sport medicine and SporTs science' (PERSiST) guidelines. METHODS: PubMed, SportDiscus and Web of Science were searched on 22nd February 2023. All study types except reviews were eligible. Studies had to report the type of eyewear worn (if any) with a form of eye injury incidence and severity. RESULTS: 364 papers were initially retrieved and after the screening process 29 remained. A subgroup analysis was carried out on studies that had a sample size of five or above, were not only looking at a particular type of eye injury and that had sufficient data to allow the percentage of eye injuries that occurred when no eyewear was worn to be calculated. From this analysis, the median percentage of eye injuries that occurred when no eyewear was worn was found to be 93%. Some of these injuries were serious and required complex treatment. Prescription lenses, contact lenses and industrial eyewear made some injuries more severe. In squash and racketball, lensless eye guards were ineffective as the ball could deform on impact, still making contact with the eye. Only eyewear compliant with updated ASTM (or similar) standards was associated with no eye injuries and so provided adequate protection in all four sports. CONCLUSIONS: Although this systematic review only summarizes evidence on injuries requiring hospital treatment, it is recommended that national governing bodies and key decision makers within squash, racketball, tennis and badminton examine the evidence presented and consider extending existing rules or implementing new recommendations and policies on protective eyewear use to reduce eye injury incidence and severity in their sport.

Balance Control is Sequentially Correlated with Proprioception, Joint Range of Motion, Strength, Pain, and Plantar Tactile Sensation Among Older Adults with Knee Osteoarthritis.

BACKGROUND: Patients with knee osteoarthritis (KOA) are at high risk for falls, which is attributed to their impaired balance control. Identifying factors associated with balance control facilitates the development of precise KOA rehabilitation programs. This study was to investigate the correlations of balance control with proprioception, plantar tactile sensation (PTS), pain, joint range of motion (ROM), and strength among older adults with and without KOA, as well as the magnitudes and sequence of correlation of these factors to balance control. METHODS: A total of 240 older adults with (n = 124, female: 84, age: 68.8 ± 4.0 years) and without (n = 116, female: 64, age: 67.9 ± 3.5 years) KOA were recruited and assigned to the KOA and control groups. Their proprioception, PTS, pain, ROM, and strength were measured. Pearson or Spearman correlations were used to test whether they were significantly related to their Berg Balance Scale (BBS), and factor analysis and multivariate linear regression were used to determine the degrees of correlation between each factor and the BBS. RESULTS: Compared to the control group, the KOA group had lower BBS score, larger proprioception and PTS thresholds, smaller ROM, and less strength (p: 0.008, < 0.001-0.016, < 0.001-0.005, < 0.001-0.014, and < 0.001-0.002, respectively). In the KOA group, the BBS was weakly to moderately correlated with proprioception, PTS, pain, ROM, and strength (r: 0.332-0.501, 0.197-0.291, 0.340, 0.212-0.508, and 0.236-0.336, respectively). While in the control group, the BBS was correlated with proprioception and strength (r: 0.207-0.379, and 0.212-0.410). In the KOA group, BBS = 54.41+ (0.668*strength) - (0.579*PTS) - (1.141*proprioception) + (1.054* ROM) - (0.339*pain). While in the control group, BBS = 53.85+ (0.441*strength) - (0.677*proprioception). CONCLUSION: Worse proprioception and PTS, smaller ROM, and less strength were detected among older adults with KOA, and their proprioception, PTS, pain, ROM, and strength were all related to balance control. Proprioception had the strongest correlations, followed by ROM, strength, pain, and PTS. Precise KOA rehabilitation programs may be proposed following the sequence of improving the five factors.

Do Exercise-Based Prevention Programs Reduce Injury in Endurance Runners? A Systematic Review and Meta-Analysis.

BACKGROUND: Endurance running is a popular sport and recreational activity yet is associated with a high prevalence of injury. Running related injuries (RRIs) are a leading cause of drop-out and represent a substantial financial burden to runners and healthcare services. There is clear evidence for the use of exercise-based injury prevention programs in games-based and youth sport settings, yet the research investigating the use of exercise to reduce injury risk in endurance runners has not been adequately reviewed recently. OBJECTIVES: The aim of this review and meta-analysis was to systematically summarize the current research that has investigated the effect of exercise-based prevention programs and their state of supervision on the risk of RRIs in endurance runners. METHODS: Three databases were searched for relevant studies. Selection and review were completed by two independent reviewers using the following inclusion criteria: (1) study population used endurance running training for health, occupational, or performance outcome(s); (2) participants performed running as their main form of exercise (> 50% of their total training time); (3) study was a randomized controlled trial; (4) a non-running-based exercise intervention was used; (5) a running-only or placebo exercise control group was included; (6) injury rate or incidence was reported; (7) injuries were recorded prospectively alongside the exercise training. Two meta-analyses were conducted using random-effects models, one based on log risk ratio and one based on log incidence rate ratio. The Cochrane Risk of Bias Assessment Tool 2 was used to evaluate the quality of studies and the Grading of Recommendations Assessment, Development and Evaluations approach was employed to grade the certainty of evidence. RESULTS: A total of nine articles containing 1904 participants were included in analysis. Overall pooled results showed no significant differences between intervention and control groups in injury risk (z = - 1.60; p = 0.110) and injury rate (z = - 0.98; p = 0.329), while a post hoc analysis evaluating supervised interventions only showed that injury risk was significantly lower in the intervention group compared to the control group (z = - 3.75, p < 0.001). Risk of bias assessment revealed that seven studies included in the analysis were of low quality. CONCLUSIONS: Exercise-based interventions do not appear to reduce the risk and rate of running-related injuries. Supervision may be essential for exercise-based intervention programs to reduce risk of RRIs, possibly due to increased compliance. Studies with more robust designs that include supervised exercise interventions should be prioritized in the future. TRIAL REGISTRY: Clinical Trial Registration: PROSPERO CRD42021211274.

Lateral Ankle Joint Injuries in Indoor and Court Sports: A Systematic Video Analysis of 445 Nonconsecutive Case Series.

BACKGROUND: Lateral ankle sprains are one of the most common injuries in indoor and court sports. Self-reports and case studies have indicated that these injuries occur via both contact and noncontact injury mechanisms typically because of excessive inversion in combination with plantarflexion and adduction of the foot. Video-based documentation of the injury mechanism exists, but the number of cases reported in the literature is limited. PURPOSE: To retrieve and systematically analyze a large number of video-recorded lateral ankle injuries from indoor and court sports, as well as describe the injury mechanism, injury motion, and injury pattern across different sports. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: A total of 445 unique video-recorded lateral ankle sprain injuries were retrieved from indoor and court sports of broadcasted levels of competition. The videos were independently analyzed by 2 different reviewers. Outcomes included classification of the injury mechanism according to the International Olympic Committee consensus guidelines, primary and secondary motions of ankle joint distortion, and documentation of the fixation point (fulcrum) around which the foot rotates. RESULTS: Overall, 298 (67%) injuries were direct contact, 113 (25%) were noncontact, and 32 (7%) were indirect contact incidents. Direct contact injuries were especially prevalent in basketball (76%), handball (80%), and volleyball (85%), while noncontact injuries dominated in tennis and badminton (96% vs 95% across both). Inversion (65%) and internal rotation (33%) were the primary distortion motions, with the lateral forefoot (53%) and lateral midfoot (40%) serving as the main fulcrums. Landing on another player's foot was the leading cause of injury (n = 246; 55%), primarily characterized by inversion (79%) around a midfoot fulcrum (54%). The noncontact and indirect landings on floor (n = 144; 33%) were primarily characterized by a distortion around a forefoot fulcrum (69%). CONCLUSION: Two of 3 ankle sprains from online video platforms were direct contact injuries, with most involving landing on another player's foot. The distortion motion seems to be related to the injury mechanism and the fixation point between the foot and the floor. The injury mechanisms varied greatly between sports, and future studies should clearly differentiate and investigate the specific injury mechanisms.

Can Arthrogenic Muscle Inhibition Exist in Peroneal Muscles Among People with Chronic Ankle Instability? A Cross-sectional Study.

BACKGROUND: Ankle sprains lead to an unexplained reduction of ankle eversion strength, and arthrogenic muscle inhibition (AMI) in peroneal muscles is considered one of the underlying causes. This study aimed to observe the presence of AMI in peroneal muscles among people with chronic ankle instability (CAI). METHODS: Sixty-three people with CAI and another sixty-three without CAI conducted maximal voluntary isometric contraction (MVIC) and superimposed burst (SIB) tests during ankle eversion, then fifteen people with CAI and fifteen without CAI were randomly invited to repeat the same tests to calculate the test-retest reliability. Electrical stimulation was applied to the peroneal muscles while the participants were performing MVIC, and the central activation ratio (CAR) was obtained by dividing MVIC torque by the sum of MVIC and SIB torques, representing the degree of AMI. RESULTS: The intra-class correlation coefficients were 0.77 (0.45-0.92) and 0.92 (0.79-0.97) for the affected and unaffected limbs among people with CAI, and 0.97 (0.91-0.99) and 0.93 (0.82-0.97) for the controlled affected and unaffected limbs among people without CAI; Significant group × limb interaction was detected in the peroneal CAR (p = 0.008). The CARs were lower among people with CAI in the affected and unaffected limbs, compared with those without CAI (affected limb = 82.54 ± 9.46%, controlled affected limb = 94.64 ± 6.37%, p < 0.001; unaffected limb = 89.21 ± 8.04%, controlled unaffected limb = 94.93 ± 6.01%, p = 0.016). The CARs in the affected limbs were lower than those in the unaffected limbs among people with CAI (p = 0.023). No differences between limbs were found for CAR in the people without CAI (p = 0.10). CONCLUSIONS: Bilateral AMI of peroneal muscles is observed among people with CAI. Their affected limbs have higher levels of AMI than the unaffected limbs.

Comparison of the in vivo kinematics between robotic-assisted Bi-cruciate retaining and Bi-cruciate stabilised total knee arthroplasty.

BACKGROUND: Up to 20% of patients remain unsatisfied after total knee arthroplasty (TKA), prompting the development of new implants. Bi-Cruciate Retaining (BCR) TKA preserves both the anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL), with the ACL beneficial for its proprioceptive qualities. The Bi-Cruciate Stabilised (BCS) TKA substitutes the ACL and PCL with a unique dual cam-post mechanism. Robotics improve accuracy and facilitate technically demanding TKA. METHODS: This was a retrospective case-control study recruited from two centres. Measured outcomes included kinematic analysis, proprioception, and functional outcomes. RESULTS: There was a significantly larger maximum flexion angle and range of flexion to extension in sit-to-stand and stairs in BCR when compared to BCS. Further analysis revealed more similarities between BCR and normal native knees. Proprioception and functional scores did not have any statistical difference. CONCLUSION: BCR TKA demonstrated better knee flexion in weight-bearing active range of motion and showed similarities with normal knee kinematics.