The effects of pulsed electromagnetic field therapy on muscle strength and pain in patients with end-stage knee osteoarthritis: a randomized controlled trial.

Background: Osteoarthritis (OA) of the knee is one of the most common chronic degenerative joint conditions affecting aging population. Aim: To investigate the effectiveness of a combination of home-based exercise and pulsed electromagnetic field (PEMF) therapy to improve muscle strength, physical function, and pain. Methods: Sixty patients were randomly assigned to either home-based exercise alone (control group; n = 30) or combined with PEMF therapy (treatment group; n = 30) twice a week for eight weeks. Knee extension, flexion muscle strength, gait speed (GS), 5 time sit-to-stand test (5STS), Visual Analogue Scale (VAS) pain and Knee Injury and Osteoarthritis Outcome Score (KOOS) were recorded at baseline and 4 and 8 weeks. Results: Significant improvements in symptomatic knee extension muscle strength (SKE, p = 0.001), flexion strength (SKF, p = 0.011), contralateral knee extension muscle strength (CKE, p = 0.002), and flexion strength (CKF, p = 0.009) were observed for the PEMF treatment group at 8 weeks. Significant reductions in VAS pain scores were observed in both the treatment (p < 0.001, partial η2 = 0.505) and control (p < 0.001, partial η2 = 0.268) groups. Significant differences were reported between groups in the 4 (p = 0.010, partial η2 = 0.111) and 8 (p = 0.046, partial η2 = 0.068) week assessment in VAS pain. A significant time difference was found in GS and 5STS between baseline and week 8 (GS: difference 0.051, p = 0.026; 5STS: difference 2.327, p < 0.001) in the treatment group. The significant group difference at week 8 was observed in SKE (p = 0.013) in female patients while pain in male patients (p = 0.026). Patients aged over 70 years have a significantly superior improvement in SKE, SKF, and CKF after 8 weeks of PEMF therapy. Conclusion: The combination of PEMF therapy and home-based exercise superiorly improved knee muscle strength and reduced pain in end-stage knee OA subjects and showed a promising tendency to improve performance-based physical function. PEMF therapy was shown to preferentially benefit knee muscle strength in female patients and patients aged over 70 years, whereas male patients were more responsive to PEMF therapy in the form of pain relief. Clinical trial registration: clinicalTrials.gov, NCT05550428.

Decreased proprioception is associated with inferior postural control during unplanned landing in individuals with chronic ankle instability.

Poor postural control during jump landing may increase ankle sprain incidences among people with chronic ankle instability (CAI). The effects of anticipation on it and its relationship with proprioception need further examination. Fifteen participants with CAI and 15 healthy controls were recruited to perform single-leg jump landings when knowing the landing side before (planned) or after (unplanned) take-off respectively, along with a step-down proprioception test differentiating four inclination platforms (inverted 12°, 14°, 16° and 18°). Ground reaction force data (peak force, loading rate and time of stabilisation) during landings and proprioception scores were collected and analysed. The CAI group exhibited a higher loading rate (59.6 ± 7.6 vs 49.4 ± 6.7 N/kg*seconds, p = 0.011) and longer medial-lateral time to stabilisation (4.82 ± 0.69 vs 4.11 ± 0.47 seconds, p = 0.023) compared to the control group during an unplanned landing. Furthermore, the above variables were negatively correlated with the step-down proprioception score only in the unplanned condition but not in the planned condition. CAI participants had inferior medial-lateral time-to-stabilisation and loading attenuation during unplanned jump landing than healthy controls, which were associated with decreased proprioception, highlighting the importance of addressing proprioception to improve balance control during unpredictable landing situations.

Contextualised physical metrics: The physical demands vary with phase of play during elite soccer match play.

The physical demands of elite soccer match play have traditionally been measured using aggregated whole-match metrics. However, match play is increasingly considered as distinct phases of play, although the influence of phase of play on match physical demands remains largely unknown. This study compared physical intensity, acceleration and deceleration demands, between phases of play and according to playing position. The duration of each match from a major European league (n = 1083) was divided into one of five reciprocal phases (for the in-/out-of-possession team) using event and tracking data: build-up/high-block, progression/mid-block, chance creation/low-block, fast attack/fast defence, or attacking transition/defensive transition. Player tracking data were used to calculate physical intensity as the rate of distance covered (m⋅min-1) in total and within five speed categories, and the proportion of time spent accelerating and decelerating (>2 m s-2) during each phase of play. Rate of distance covered in total differed markedly with phase of play; fast attack 35%-53% greater, and fast defence 33%-50% greater, than other in-/out-of-possession phases respectively, and these effects were amplified for the rate of distance covered at higher speeds (e.g., sprinting ≥4-fold differences between phases). Match phase also affected the proportion of time spent accelerating and decelerating (highest for fast attack and chance creation, respectively), especially when in-possession for forwards and when out-of-possession for defenders (p < 0.001). Phase of play had a large effect on the physical intensity of match play, particularly rates of distance covered at higher speeds, as well as the acceleration and deceleration demands, and in a position specific manner.

Different strategies for landing from different heights among people with chronic ankle instability.

BACKGROUND: Lateral ankle sprain (LAS) usually occurs during landing from heights among people with chronic ankle instability (CAI). Although the kinematics when landing on the flat surface has been reported, no studies have explored the effect of different heights on the landing strategies using a trapdoor device among people with CAI. RESEARCH QUESTION: Do people with CAI adopt different landing strategies when drop-landing on the trapdoor device from three heights? METHODS: Thirty-one participants with CAI (24 males and 7 females, age=21.1±1.8 years, height=176.9±7.4 cm, body mass=71.9±9.2 kg, injured side=18 R&13 L) were recruited. They dropped from three different heights (low height (16 cm), medium height (23 cm), high height (30 cm)) with their affected foot landing on a movable surface of a trapdoor device, which was tilted 24° inward and 15° forward to simulate LAS. Kinematic data was collected using a twelve-camera motion capture system. One-way analysis of variance with repeated measures was used to compare the differences between the three heights. RESULTS: Significant height effects were detected in the peak ankle inversion angle (p=0.009, η2p=0.280) and angular velocity (p<0.001, η2p=0.444), and the peak ankle plantarflexion (p=0.002, η2p=0.360), knee flexion (p<0.001, η2p=0.555), and hip flexion (p=0.030, η2p=0.215) angles at the time of peak ankle inversion. Post-hoc tests showed that all the angles and velocities were higher at a low height than at medium (p: 0.001-0.045, d: 0.14-0.44) and high heights (p: 0.001-0.023, d: 0.28-0.66), except for the ankle plantarflexion angle, which was lower at a low height than at medium (p<0.001, d=0.44) and high (p=0.021, d=0.38) heights. SIGNIFICANCE: People with CAI adopt a protective strategy during drop-landing at medium and high heights compared to a low height. This strategy involves increased ankle dorsiflexion angle as well as knee and hip flexion angles.

Does lower extremity stiffness influence change of direction speed in badminton athletes after dynamic loaded warm-up?

This study investigated whether lower extremity stiffness plays a role in the enhancement of change of direction speed (CODS) and the duration of this enhancement after dynamic loaded warm-up (DLWU). Fifteen badminton athletes underwent DLWU, and CODS, individual muscle and tendon stiffness, and vertical stiffness were measured before DLWU and 6, 12, and 18 min after DLWU. The data were analyzed using ANOVA and covariance analysis. Significant improvements in CODS were found at 6, 12, and 18 min post-DLWU compared to pre-DLWU (p < 0.05). The Achilles tendon stiffness of the dominant leg increased at 6 min (p = 0.039) and 18 min (p = 0.024) post-DLWU compared to pre-DLWU. Achilles tendon stiffness of the dominant leg had a significant effect on improving CODS (p > 0.05). CODS improvement lasted up to 18 min after DLWU in badminton athletes, potentially related to increased Achilles tendon stiffness of the dominant leg.

Correlations of Postural Stability to Proprioception, Tactile Sensation, and Strength Among People With Chronic Ankle Instability.

OBJECTIVES: The static and dynamic correlations of postural stability to its three potential contributors, namely, proprioception, tactile sensation, and strength remain unclear among people with chronic ankle instability (CAI). This study aimed to compare static and dynamic postural stability, along with proprioception, tactile sensation, and strength between people with and without CAI and explore their correlations. METHODS: Sixty-seven participants with CAI and 67 participants without CAI were enrolled in this study. Ankle proprioception, plantar tactile sensation, and lower limb strength were measured by a proprioception test device, a set of monofilaments, and a strength testing system, respectively. Static and dynamic postural stability were measured during standing and jump landing on a force plate and indicated by the root mean square of center of pressure and time to stability. RESULTS: Compared to people without CAI, people with CAI had poorer postural stability, proprioception, tactile sensation, and strength. Both groups demonstrated correlation between proprioception and static postural stability, but only people without CAI showed correlation between proprioception and dynamic postural stability. Both groups demonstrated a correlation between tactile sensation and static postural stability, but not with dynamic stability. Both groups demonstrated a correlation between strength and both static and dynamic postural stability. CONCLUSIONS: People with CAI had deficits in static and dynamic postural stability, proprioception, tactile sensation, and strength. Among people with CAI, proprioception, tactile sensation, and strength can help maintain static postural stability; strength can help maintain dynamic postural stability, whereas proprioception may not provide sufficient information for dynamic postural stability.

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.

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.

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.

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.

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.

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.

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.

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.

Ankle Biomechanics During Multidirectional Landings in Athletes With Chronic Ankle Instability.

BACKGROUND: Assessing and understanding the control of the ankle during multidirectional jump landings in athletes with chronic ankle instability (CAI) would help health professionals develop interventions to reduce the risk of recurrent injuries. The aim of this study was to investigate the angle, angular velocity, and movements of the ankle joint, and the muscle activity of peroneus longus (PL), tibialis anterior (TA), and gastrocnemius (GAS) muscles during multidirectional landings in athletes with CAI. METHODS: Nineteen athletes with CAI (≤25 Cumberland Ankle Instability Tool-Thai Score) participated. A Vicon Nexus motion analysis system synchronously collected data with an AMTI force plate and surface electromyography (EMG) to capture kinematics, kinetics, and muscle activity, respectively. Participants were asked to perform single-leg jump-landing tests in forward (0°), 30° diagonal, 60° diagonal, and lateral (90°) directions. Ankle joint kinematics, kinetics, and muscle activity of PL, TA, and GAS were analyzed. Repeated measure ANOVA (analysis of variance) and Friedman tests were used to analyze the main effects of the jump-landing direction. RESULTS: Athletes with CAI exhibited significant differences in ankle angles, angular velocities, ankle movements, and average muscle activity of GAS between directions. Greatest average EMG of GAS muscle was observed during landing in the lateral direction compared with the forward and 30° diagonal directions. CONCLUSION: Lateral and diagonal direction movements showed the greatest risks associated with recurrent ankle sprains. Impairments of neuromuscular control in both pre-landing and landing phases were observed in athletes with CAI when considered alongside previously published data. LEVEL OF EVIDENCE: Laboratory-based observational study.

The influence of ball in/out of play and possession in elite soccer: Towards a more valid measure of physical intensity during competitive match-play.

The physical demands of soccer match-play have typically been assessed using a low-resolution whole match approach ignoring whether the ball is in or out of play (BIP/BOP) and during these periods which team has possession. This study investigated the effect of fundamental match structure variables (BIP/BOP, in/out of possession) on the physical demands, and especially intensity, of elite match-play. For 1083 matches from a major European league, whole match duration, and player physical tracking data, were divided into BIP/BOP, and in/out of possession periods throughout the match, using on-ball event data. These distinct phases were used to derive absolute (m) and rate (m·min-1) of distance covered in total and within six speed categories during BIP/BOP and in/out possession. The rate of distance covered, an index of physical intensity, was >2-fold greater during BIP vs BOP. Whole match total distance covered was confounded by BIP time and poorly associated with physical intensity during BIP (r = 0.36). Whole match rates of distance covered substantially underestimated those during BIP, particularly for higher running speeds (∼-62%). Ball possession markedly effected physical intensity, with the rates of distance covered running (+31%), at high-speed (+30%) and in total (+7%) greater out than in possession. Whole match physical metrics underestimated the physical intensity during BIP, and thus the rate(s) of distance covered during BIP are recommended for accurate measurement of physical intensity in elite soccer. The greater demands of being out of possession support a possession-based tactical approach to minimise fatigue and its negative consequences.

This large-scale study utilising >1000 elite level competitive matches found profound differences in rate of distance covered between periods of BIP vs BOP, being 2-fold higher overall and 8- to 33-fold higher for the rates of distance covered within running, high-speed and sprinting speed categories.Consequently, commonly used whole match physical metrics, that incorporate both BIP and BOP, such as distances covered but even rates of distance covered, were not valid indices of physical intensity (rate of distance covered) during BIP.Thus a more valid and direct approach to quantifying physical intensity during elite soccer match-play as the rate of distance covered during BIP is proposed.Utilising a unique within-match analysis the effect of possession (i.e. in vs out) revealed that teams covered ≥30% more running and high-speed distance while out than in possession during BIP.

Cross-cultural adaptation, reliability and validity of the Cantonese-Chinese Cumberland Ankle Instability Tool (CAIT-HK).

Acute lateral ankle sprains are common amongst athletes, and screening is essential in preventing these long-term sequelae. Self-reported questionnaires, such as the Cumberland Ankle Instability Tool (CAIT), may help identify individuals with chronic ankle instability. To date, a Cantonese-Chinese version of the CAIT does not exist. A cross-cultural adaptation and validation of the CAIT were carried out: 46 individuals who were native in Cantonese completed the Cantonese-Chinese version of the CAIT and Chinese Foot and Ankle Outcome Score. For the test-retest analysis, the intraclass correlation coefficient was 0.874. Internal consistency showed a Cronbach's ɑ value of 0.726. Construct validity against the FAOS was fair but statistically significant with a Spearman's correlation coefficient of 0.353, 0.460, 0.303, 0.369 and 0.493 for the categories of symptoms, pain, daily function, sports function, and quality of life, respectively. A cutoff score of 20.5 was determined to differentiate healthy individuals from those with chronic ankle instability for this study population. The original English CAIT was successfully translated, cross-culturally adapted and validated into Cantonese-Chinese.

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.

Dual Mobility Total Hip Replacements in Young Patients- A Systematic Review.

Background: There is little consensus on outcomes of dual Mobility total hip replacement (DM-THR) in younger patients. We performed a systematic review to examine this. Methods: A systematic review of all observational studies and randomised controlled trials of patients under 70 with primary DM-THR in MEDLINE, EMBASE, Pubmed, Cochrane was performed according to PRISMA guidelines. Collected data included demographics, revision, dislocation and infection rates and functional scores. Results: Twelve papers studying 738 DM-THR in 664 patients were included. The mean patient age was 46.9 years (13.5-69.0), with 319 (48.0%) being female and 419 (52.0%) being male. After an average follow-up of 90.0 months (1-371 months), the revision rate was 12.7% (84 hips), 0 dislocations were reported but 2.5% (15 hips) underwent intra-prosthetic dislocation. 32.1% hip revisions were due to aseptic loosening. Conclusion: Limited literature surrounding the use of DM-THR suggests favourable stability but higher revision rates than conventional THR.