Year-round longitudinal health surveillance in UK Olympic Summer Sport Athletes 2016-2019.

OBJECTIVES: To identify the priority injury and illness types across UK summer Olympic World Class Programme sports to inform development, implementation and evaluation of associated injury risk mitigation and management initiatives. METHODS: Four years (2016-2019) of electronic medical records of 1247 athletes from 22 sports were analysed and reported using methods based on the 2020 International Olympic Committee consensus statement for epidemiological recording and reporting. RESULTS: 3562 injuries and 1218 illness were recorded, accounting for 146 156 and 27 442 time-loss days. Overall, 814 (65%) athletes reported at least one injury, while 517 (41%) reported at least one illness. There were 1.3 injuries per athlete year resulting in a mean burden of 54.1 days per athlete year. The lumbar/pelvis, knee, ankle and shoulder body regions had the highest incidence and burden. Athletes reported 0.5 illnesses per athlete year, resulting in a mean burden of 10.4 days per athlete year, with most composed of respiratory illness and gastroenteritis. Injuries within sport groups were representative of the injury risk profile for those sports (eg, knee, hand and head injuries had the highest incidence in combat sports), but respiratory illnesses were consistently the greatest problem for each sport group. CONCLUSIONS: To optimise availability for training and performance, systematic risk mitigation and management initiatives should target priority injury problems occurring in the lumbar/pelvis, knee, ankle and shoulder, and respiratory illness. Follow-up analysis should include identification of sport-specific priority health problems and associated risk factors.

The Effect of Exercise Therapy Interventions on Shoulder Pain and Musculoskeletal Risk Factors for Shoulder Pain in Competitive Swimmers: A Scoping Review.

CONTEXT: Shoulder pain is the main cause of missed or modified training in competitive swimmers. Exercise therapy can improve the outcomes, yet uncertainty exists regarding the characteristics of these interventions. OBJECTIVES: The primary aim was to describe the evidence base relating to the effectiveness of exercise therapy interventions on shoulder pain and shoulder musculoskeletal risk factors for shoulder pain in swimmers. The secondary aim was to identify gaps in the literature and provide recommendations for future research and practice. EVIDENCE ACQUISITION: A scoping review methodology was applied through the search of MEDLINE, PubMed, Scopus, Web of Science, and CINAHL databases. The authors included any research studies (except clinical commentaries and conference papers) that assess the effect of exercise therapy on shoulder pain and musculoskeletal risk factors for shoulder pain in swimmers. The literature was critically appraised using the Modified Down and Black checklist. EVIDENCE SYNTHESIS: From 452 papers identified, 14 studies were included in this review. An exercise program of 6 to 8 weeks, including strengthening exercises (shoulder external rotator and scapula retractor muscles) and stretches (pectoral muscles), can decrease the incidence of shoulder pain in swimmers. Furthermore, a combination of exercises and stretches with manual therapy techniques can help to decrease shoulder pain in injured swimmers. Regarding risk factors, a strengthening program of more than 12 weeks increased shoulder external rotation peak force, endurance, and external rotation/internal rotation ratio; however, this was not associated to decreases in pain. Finally, open kinetic chain exercises and a dry-land program are superior to close kinetic exercises and water training for improving shoulder external rotation strength and endurance. CONCLUSIONS: Exercise therapy has positive effects on reducing the incidence of shoulder pain, the management of shoulder pain, and improving shoulder musculoskeletal risk factors in competitive swimmers. However, due to methodological limitations of the studies, caution must be used when applying these results in practice. Future research should focus on high-quality randomized controlled trials for prevention and management of shoulder pain in swimmers.

The effect of speed on Achilles tendon forces and patellofemoral joint stresses in high-performing endurance runners.

Achilles tendinopathy and patellofemoral pain are common running injuries associated with increased Achilles tendon (AT) forces and patellofemoral joint (PFJ) stresses. This study examined AT forces and PFJ stresses at different running speeds in high-performing endurance runners. Twenty runners ran overground at four running speeds (3.3, 3.9, 4.8, and 5.6 m/s). AT forces and PFJ stresses were estimated from kinematic and kinetic data. Repeated measures ANOVA with partial eta squared effect sizes was conducted to assess differences between running speeds. Increased peak AT forces (19.5%; p < 0.001) and loading rates (57.3%; p < 0.001) from 3.3 m/s to 5.6 m/s were observed. Cumulative AT loading was greater in the faster speeds compared to the slower speeds. Faster running speeds resulted in increased peak plantar flexor moments, increased peak plantar flexion angles, and a more flexed knee and an anterior center of pressure position at touchdown. Peak PFJ stress was lower in the slowest speed (3.3 m/s) compared to the faster running speeds (3.9-5.6 m/s; p = 0.005). PFJ stress loading rate significantly increased (43.6%; p < 0.001). Greater AT loading observed could be associated with strategies such as increased plantar flexor moments and altered lower body position at touchdown which are commonly employed to generate greater ground contact forces. Greater AT and PFJ loading rates were likely due to shorter ground contact times and therefore less time available to reach the peak. Running at faster speeds could increase the risk of developing Achilles tendinopathy and patellofemoral pain or limit recovery from these injuries without sufficient recovery.

Return to sport decisions after an acute lateral ankle sprain injury: introducing the PAASS framework-an international multidisciplinary consensus.

BACKGROUND: Despite being the most commonly incurred sports injury with a high recurrence rate, there are no guidelines to inform return to sport (RTS) decisions following acute lateral ankle sprain injuries. We aimed to develop a list of assessment items to address this gap. METHODS: We used a three-round Delphi survey approach to develop consensus of opinion among 155 globally diverse health professionals working in elite field or court sports. This involved surveys that were structured in question format with both closed-response and open-response options. We asked panellists to indicate their agreement about whether or not assessment items should support the RTS decision after an acute lateral ankle sprain injury. The second and third round surveys included quantitative and qualitative feedback from the previous round. We defined a priori consensus being reached at >70% agree or disagree responses. RESULTS: Sixteen assessment items reached consensus to be included in the RTS decision after an acute lateral ankle sprain injury. They were mapped to five domains with 98% panellist agreement-PAASS: Pain (during sport participation and over the last 24 hours), Ankle impairments (range of motion; muscle strength, endurance and power), Athlete perception (perceived ankle confidence/reassurance and stability; psychological readiness), Sensorimotor control (proprioception; dynamic postural control/balance), Sport/functional performance (hopping, jumping and agility; sport-specific drills; ability to complete a full training session). CONCLUSION: Expert opinion indicated that pain severity, ankle impairments, sensorimotor control, athlete perception/readiness and sport/functional performance should be assessed to inform the RTS decision following an acute lateral ankle sprain injury. TRIAL REGISTRATION NUMBER: ACTRN12619000522112.

Quadriceps Strength and Functional Performance After Anterior Cruciate Ligament Reconstruction in Professional Soccer players at Time of Return to Sport.

ABSTRACT: Herrington, L, Ghulam, H, and Comfort, P. Quadriceps strength and functional performance after anterior cruciate ligament reconstruction in professional soccer players, at time of return to sport. J Strength Cond Res 35(3): 769-775, 2021-Poor quadriceps strength has been associated with poor outcome after anterior cruciate ligament (ACL) reconstruction (ACLR). This study aims to assess quadriceps strength, muscle inhibition, and hop test performance in professional soccer players after ACLR. Fifteen professional soccer players (age 22.3 ± 3.1 years, body mass 81.0 ± 11.5 kg, and height 1.75 ± 0.1 m) who had undergone ACLR participated. Isometric, eccentric, and concentric quadriceps strength was assessed, along with quadriceps inhibition and single and cross-over hop performance, at the time of return to full-time unrestricted play. In comparison with the uninjured leg, the ACLR leg demonstrated large significant (d ≥ 0.84, p < 0.01) deficits in isometric, eccentric, and concentric quadriceps strength, quadriceps inhibition, and hop distance. Over 80% of the players failed to exceed the limb symmetry criteria of ≥90% for strength tests, although 75% of the cohort passed the ≥90% criteria for hop tests. The outcome from ACLR in professional soccer players who received full-time intensive rehabilitation has not previously been reported in detail. There were significant deficits in quadriceps strength at the time of return to sport, whereas hop testing, a commonly used outcome measure, failed to show the same levels of deficit. These deficits in quadriceps function may have implications for the development of ongoing knee symptoms and risk of future ACL injury. If this proves to be the case, then it would seem that greater attention should be paid to re-establishing full quadriceps strength before returning to unrestricted sporting activity.

The Test-Retest Reliability of Bilateral and Unilateral Force Plate-Derived Parameters of the Countermovement Push-Up in Elite Boxers.

CONTEXT: Maximal power describes the ability to immediately produce power with the maximal velocity at the point of release, impact, and/or take off-the greater an athlete's ability to produce maximal power, the greater the improvement of athletic performance. In reference to boxing performance, regular consistent production of high muscular power during punching is considered an essential prerequisite. Despite the importance of upper limb power to athletic performance, presently, there is no gold standard test for upper limb force development performance. OBJECTIVE: To investigate the test-retest reliability of the force plate-derived measures of countermovement push-up in elite boxers. DESIGN: Test-retest design. SETTING: High Performance Olympic Training Center. PARTICIPANTS: Eighteen elite Olympic boxers (age = 23 [3] y; height = 1.68 [0.39] m; body mass = 70.0 [17] kg). INTERVENTION: Participants performed 5 repetitions of countermovement push-up trials on FD4000 Forcedeck dual force platforms on 2 separate test occasions 7 days apart. MAIN OUTCOME MEASURES: Peak force, mean force, flight time, rate of force development, impulse, and vertical stiffness of the bilateral and unilateral limbs from the force-time curve. RESULTS: No significant differences between the 2 trial occasions for any of the derived bilateral or unilateral performance measures. Intraclass correlation coefficients indicated moderate to high reliability for performance parameters (intraclass correlation coefficients = .68-.98) and low coefficient of variation (3%-10%) apart from vertical stiffness (coefficient of variation = 16.5%-25%). Mean force demonstrated the greatest reliability (coefficient of variation = 3%). In contrast, no significant differences (P < .001) were noted between left and right limbs (P = .005-.791), or between orthodox or southpaw boxing styles (P = .19-.95). CONCLUSION: Force platform-derived kinetic bilateral and unilateral parameters of countermovement push-up are reliable measures of upper limb power performance in elite-level boxers; results suggest unilateral differences within the bilateral condition are not the norm for an elite boxing cohort.

Could Relative Movement Between the Adductor Muscles and the Skin Invalidate Surface Electromyography Measurement?

The superficial hip adductor muscles are situated in close proximity to each other. Therefore, relative movement between the overlying skin and the muscle belly could lead to a shift in the position of surface electromyography (EMG) electrodes and contamination of EMG signals with activity from neighboring muscles. The aim of this study was to explore whether hip movements or isometric contraction could lead to relative movement between the overlying skin and 3 adductor muscles: adductor magnus, adductor longus, and adductor gracilis. The authors also sought to investigate isometric torque-EMG relationships for the 3 adductor muscles. Ultrasound measurement showed that EMG electrodes maintained a position which was at least 5 mm within the muscle boundary across a range of hip flexion-extension angles and across different contraction levels. The authors also observed a linear relationship between torque and EMG amplitude. This is the first study to use ultrasound to track the relative motion between skin and muscle and provides new insight into electrode positioning. The findings provide confidence that ultrasound-based positioning of EMG electrodes can be used to derive meaningful information on output from the adductor muscles and constitute a step toward recognized guidelines for surface EMG measurement of the adductors.

The Test-Retest Reliability of Force Plate-Derived Parameters of the Countermovement Push-Up as a Power Assessment Tool.

CONTEXT: Muscular power output of the upper limb is a key aspect of athletic and sporting performance. Maximal power describes the ability to immediately produce power with maximal velocity at the point of release, impact, or takeoff, with research highlighting that the greater an athlete's ability to produce maximal power, the greater the improvement in athletic performance. Despite the importance of upper-limb power for athletic performance, there is presently no gold-standard test for upper-limb force development performance. OBJECTIVE: The aim of this study was to investigate the test-retest reliability of force plate-derived measures of the countermovement push-up in active males. DESIGN: Test-retest design. SETTING: Controlled laboratory. PARTICIPANTS: Physically active college athletes (age 24 [3] y, height 1.79 [0.08] m, body mass 81.7 [9.9] kg). INTERVENTION: Subjects performed 3 repetitions of maximal effort countermovement push-up trials on Kistler force plates on 2 separate test occasions 7 days apart. MAIN OUTCOME MEASURES: Peak force, mean force, flight time, rate of force development, and impulse were analyzed from the force-time curve. RESULTS: No significant differences between the 2 trial occasions were observed for any of the derived performance measures. Intraclass correlation coefficient and within-subject coefficient of variation calculations indicated performance measures to have moderate to very high reliability (intraclass correlation coefficient = .88-.98), coefficient of variation = 5.5%-14.1%). Smallest detectable difference for peak force (7.5%), mean force (8.6%), and rate of force development (11.2%) were small to moderate. CONCLUSION: Force platform-derived kinetic parameters of countermovement push-up are reliable measurements of power in college-level athletes.

Testing Shoulder Pain Mapping.

OBJECTIVE: A previous study on shoulder pain mapping showed specific pain patterns for common shoulder disorders. This study aimed to test those patterns for accuracy, modify shoulder pain mapping as needed, and observe their reliability and validity. METHODS: This prospective study used a two-step process and was undertaken to determine its potential utility in daily practice. New shoulder pain patients marked their pain, its character and severity, on a custom-made mapping form. Then a researcher blinded to the diagnoses gave their estimations on the basis of previously established maps, and they were correlated with final diagnoses. Subsequently, a guide table was developed on how to read the maps, and intertester reliability was performed with three independent testers. RESULTS: The study included 194 patients, and the overall accuracy for estimations was between 45.4% and 49.5%. The sensitivity was high, especially for instability, followed by calcific tendinitis, acromio-calvicular joint pathology, and impingement. The intertester reliability showed clinically significant agreement between testers for both disease groups (κ = 0.70) and individual disorders (κ = 0.52). CONCLUSIONS: This was a unique and extensive study on shoulder pain mapping. The study concluded that pain mapping could be a useful adjunct to the clinical assessment of patients with shoulder pain and can be used in the primary care setting as well as secondary care and for research.

The Relationship Between 2-Dimensional Knee-Valgus Angles During Single-Leg Squat, Single-Leg-Land, and Drop-Jump Screening Tests.

CONTEXT: Injuries to the anterior cruciate ligament (ACL) and patellofemoral joint (PFJ) are a significant problem in female athletes. A number of screening tasks have been used in the literature to identify those at greatest risk of injury. To date, no study has examined the relationship in 2-dimensional (2D) knee valgus between common screening tasks to determine whether individuals exhibit similar movement patterns across tasks. OBJECTIVE: To establish whether frontal-plane projection angle (FPPA) during the single-leg squat (SLS), single-leg land (SLL), and drop jump (DJ) are related. DESIGN: Cross-sectional study. SETTING: University laboratory. PARTICIPANTS: 52 national-league female football players and 36 national-league female basketball players. MAIN OUTCOME MEASURES: 2D FPPA during the SLS, SLL, and DJ screening tasks. RESULTS: Significant correlations were found between tasks. FPPA in the SLS was significantly correlated with SLL (r = .52) and DJ (r = .30), whereas FPPA in the SLL was also significantly correlated to DJ (r = .33). FPPA was significantly greater in the SLS than in the SLL (P < .001) and DJ (P < .001) and in the SLL than in the DJ (P < .001). CONCLUSION: The results showed that 2D FPPA is correlated across the SLS, SLL, and DJ tasks. However, significantly greater FPPA values in the unilateral tasks suggest that the DJ may not identify risk of injury in sports where primary injury mechanisms are during unilateral loading tasks. Therefore, it is recommended that both unilateral and bilateral tasks be included when screening for ACL and PFJ injury risk.

Lack of Effect of Ankle Position During the Nordic Curl on Muscle Activity of the Biceps Femoris and Medial Gastrocnemius.

CONTEXT: Regular performance (~2×/wk) of Nordic curls has been shown to increase hamstring strength and reduce the risk of hamstring strain injury, although no consensus on ankle position has been provided. OBJECTIVE: To compare the effects of performing Nordic curls, with the ankle in a dorsiflexed (DF) or plantar-flexed (PF) position, on muscle activity of the biceps femoris (BF) and medial gastrocnemius (MG). PARTICIPANTS: 15 male college athletes (age 22.6 ± 2.1 y, height 1.78 ± 0.06 m, body mass 88.75 ± 8.95 kg). DESIGN: A repeated-measures design was used, with participants performing 2 sets of 3 repetitions of both variations of Nordic curls, while muscle activity was assessed via surface electromyography (EMG) of the BF and MG. Comparisons of muscle activity were made by examining the normalized EMG data as the percentage of their maximum voluntary isometric contraction. RESULTS: Paired-samples t test revealed no significant difference in normalized muscle activity of the BF (124.5% ± 6.2% vs 128.1 ± 5.0%, P > .05, Cohen d = 0.64, power = .996) or MG (82.1% ± 3.9% vs 83.5 ± 4.8%, P > .05, Cohen d = 0.32, power = .947) during the Nordic curls in a PF or DF position, respectively. CONCLUSION: Ankle position does not influence muscle activity during the Nordic curl; however, performance of Nordic curls with the ankle in a DF position may be preferential, as this replicates the ankle position during terminal leg swing during running, which tends to be the point at which hamstring strains have been reported.

The Effects of Rigid Scapular Taping on Acromiohumeral Distance in Healthy Shoulders: An Observational Study.

CONTEXT: Compromise to the acromiohumeral distance (AHD) has been reported in subjects with subacromial impingement syndrome when compared with healthy subjects. In clinical practice, patients are taped with the intention of altering scapular position and influencing the AHD. However, research to determine the effects of taping on AHD is exiguous. OBJECTIVES: To evaluate the effect of ridged taping techniques to increase posterior scapular tilt and upward scapular rotation on the AHD. DESIGN: 1-group pretest/posttest repeated-measures design. SETTING: Human performance laboratory. PARTICIPANTS: 20 asymptomatic participants (10 male and 10 female) age 27 y (SD 8.0 y). INTERVENTION: Ridged tapping of the scapula into posterior tilt and upward scapular rotation. MAIN OUTCOME MEASURE: Ultrasound measurement of the AHD. RESULTS: AHD increased significantly after rigid tape application to the scapula (P < .003) in healthy shoulders in 60° of passive arm abduction. CONCLUSION: Taping techniques applied to the scapula had an immediate effect of increasing the AHD in healthy shoulders in 60° of passive arm abduction. Results suggest that taping for increasing posterior scapular tilt and increasing scapular upward rotation can influence the AHD and is a useful adjunct to rehabilitation in patients with subacromial impingement syndrome.

The Inter-rater Reliability of the Functional Movement Screen Within an Athletic Population Using Untrained Raters.

Elias JE. The inter-rater reliability of the functional movement screen within an athletic population using untrained raters. J Strength Cond Res 30(9): 2591-2599, 2016-The functional movement screen (FMS) is a commonly used screening tool designed to identify restrictions to movement patterns and increased injury risk using 7 predesigned tests. The purpose of this study was to analyze the inter-rater reliability of scoring of the FMS using a group of "untrained" subjects. Additionally, the study also examined if clinical experience level had any effect on reliability. Twenty fully qualified Physiotherapists working at the English Institute of Sport, with elite athletes, volunteered to participate in the study. The group comprised both level 2 and level 3 physiotherapists based on clinical experience levels. Five elite athletes, free from injury, were recruited and videoed completing 6 of the 7 FMS tests using a 3 camera system. The videos were scored by each Physiotherapist using the standardized scoring sheet, as developed by Cook et al. Each practitioner marked each athlete completing the 6 tests. The total scores were calculated for each athlete (maximum score of 18). The inter-rater reliability of the test was shown to be high, intraclass coefficient 0.906. An independent t test showed no significant differences between the level 2 and level 3 practitioners in the total scores (p = 0.502). The results of the test indicate that the FMS is a reliable screening tool when used by untrained practitioners in determining faulty movement patterns and that clinical experience level does not affect the reliability, therefore it may be a useful tool in the screening of athletic populations.

Criterion-related validity of knee joint-position-sense measurement using image capture and isokinetic dynamometry.

CONTEXT: Clinicians require portable, valid, and cost-effective methods to monitor knee joint-position-sense (JPS) ability. OBJECTIVE: To examine the criterion-related validity of image-capture JPS measures against an isokinetic-dynamometer (IKD) procedure. DESIGN: Random crossover design providing a comparison of knee JPS measures from image capture and IKD procedures. PARTICIPANTS: 10 healthy participants, 5 female, age 28.0 ± 13.29 y, mass 60.3 ± 9.02 kg, height 1.65 ± 0.07 m, and 5 male, 29.6 ± 10.74 y, mass 73.6 ± 5.86 kg, height 1.75 ± 0.07 m. MAIN OUTCOME MEASURES: The dependent variables were absolute error scores (AES) provided by 2 knee directions (flexion and extension). The independent variables were the method (image capture and IKD). RESULTS: There was no significant difference between clinical and IKD AES into knee-flexion data (P = .263, r = 0.55). There was a significant difference between clinical and IKD AES into knee-extension data (P = .016, r = .70). CONCLUSIONS: Analysis of photographic images to assess JPS measurements using knee flexion is valid against an IKD positioning method, but JPS measurements using knee extension may not be valid against IKD techniques. However, photo-analysis measurements provided a lower error score using knee-extension data and thus may provide an optimal environment to produce maximal knee JPS acuity. Therefore, clinicians do not need expensive equipment to collect representative JPS ability.

Interexaminer, intraexaminer and test-retest reliability of clinical knee joint-position-sense measurements using an image-capture technique.

CONTEXT: Knee joint-position sense (JPS) plays a critical role in controlled and stable joint movement. Poor ability to sense position of the knee can therefore increase risk of injury. There is no agreed consensus on JPS measurement techniques and a lack of reliability statistics on methods. OBJECTIVE: To identify the most reliable knee JPS measurement technique using image capture. DESIGN: Interexaminer, intraexaminer, and test-retest reliability of knee JPS measurements. SETTING: Biomechanics laboratory. PARTICIPANTS: 10 asymptomatic participants. INTERVENTIONS: None. MAIN OUTCOME MEASURES: Relative and absolute error scores of knee JPS in 3 conditions (sitting, prone, active) through 3 ranges of movement (10-30°, 30-60°, 60-90°), into 2 directions (flexion and extension) using both legs (dominant and nondominant) collected during 15 trials and repeated 7 d after the first data collection. RESULTS: Statistical analysis by intraclass correlations revealed excellent interexaminer reliability between researchers (.98) and intraexaminer reliability within 1 researcher (.96). Test-retest reliability was highest in the sitting condition from a starting angle of 0°, target angle through 60-90° of flexion, using the dominant leg and absolute-error-score variables (ICC = .92). However, it was noted smallest detectable differences were a high percentage of mean values for all measures. CONCLUSIONS: The most reliable JPS measurement for asymptomatic participants has been identified. Practitioners should use this protocol when collecting JPS data during prescreening sessions. However, generalizability of findings to a class/group of clients exhibiting knee pathologies should be done with caution.

Position statement on youth resistance training: the 2014 International Consensus.

The current manuscript has been adapted from the official position statement of the UK Strength and Conditioning Association on youth resistance training. It has subsequently been reviewed and endorsed by leading professional organisations within the fields of sports medicine, exercise science and paediatrics. The authorship team for this article was selected from the fields of paediatric exercise science, paediatric medicine, physical education, strength and conditioning and sports medicine.

Knee Offloading by Patients During Walking and Running After Meniscectomy.

Background: Changes in knee loading have been reported after meniscectomy. Knee loading has previously been assessed during jogging and treadmill running rather than overground running, which could give altered results. Purpose/Hypothesis: The purpose of this study was to evaluate knee function during overground running and walking after meniscectomy. It was hypothesized that the affected limb would demonstrate higher external knee adduction moment, lower knee flexion moment (KFM), and lower knee rotation moment (KRM) compared with the contralateral limb and with healthy individuals. Study Design: Controlled laboratory study. Methods: Kinematic and kinetic data were collected during running and walking in individuals after a meniscectomy and healthy individuals. Total knee joint moments (TKJM) were calculated from the sagittal, frontal, and transverse knee moments. Isometric quadriceps strength, perceived knee function, and kinesiophobia were also assessed. A mixed linear model compared differences between the affected leg, the contralateral leg, and the healthy leg. Results: Data were collected on 20 healthy individuals and 30 individuals after a meniscectomy (mean ± SD, 5.7 ± 2.9 months postsurgery), with 12, 16, and 2 individuals who had medial, lateral, and both medial and lateral meniscectomy, respectively. The affected limb demonstrated lower TKJM (P < .001), KFM (P = .004), and KRM (P < .001) during late stance of walking compared with the healthy group. Lower TKJM and KFM were observed during running in the affected limb compared with the contralateral limb and healthy group. No significant differences were observed between contralateral and healthy limbs except for KRM during late stance of walking. Lower quadriceps strength was observed in the affected (P < .001) and contralateral limbs (P = .001) compared with the healthy group. Individuals after a meniscectomy also reported greater kinesiophobia (P = .006) and lower perceived knee function (31.1%; P < .001) compared with the healthy group. Conclusion: After meniscectomy, individuals who sustained a traumatic meniscal injury showed lower TKJM in the affected limb compared with the contralateral limb and healthy individuals. This decrease in TKJM can be attributed to altered knee-loading strategies in the sagittal and transverse planes. Clinical Relevance: Improving movement strategies, quadriceps strength, and kinesiophobia through rehabilitation approaches will allow individuals to load their knee appropriately when returning to sport. Registration: NCT03379415 (ClinicalTrials.gov identifier).

Does high-intensity running to fatigue influence lower limb injury risk?

OBJECTIVES: The aim of this study was to quantify changes in peak bending moments at the distal tibia, peak patellofemoral joint contact forces and peak Achilles tendon forces during a high-intensity run to fatigue at middle-distance speed. DESIGN: Observational study. METHODS: 16 high-level runners (7 female) ran on a treadmill at the final speed achieved during a preceding maximum oxygen uptake test until failure (~3 min). Three-dimensional kinetics and kinematics were used to derive and compare tibial bending moments, patellofemoral joint contact forces and Achilles tendon forces at the start, 33 %, 67 % and the end of the run. RESULTS: Average running speed was 5.7 (0.4) m·s-1. There was a decrease in peak tibial bending moments (-6.8 %, p = 0.004) from the start to the end of the run, driven by a decrease in peak bending moments due to muscular forces (-6.5 %, p = 0.001), whilst there was no difference in peak bending moments due to joint reaction forces. There was an increase in peak patellofemoral joint forces (+8.9 %, p = 0.026) from the start to the end of the run, but a decrease in peak Achilles tendon forces (-9.1 %, p < 0.001). CONCLUSIONS: Running at a fixed, high-intensity speed to failure led to reduced tibial bending moments and Achilles tendon forces, and increased patellofemoral joint forces. Thus, the altered neuromechanics of high-intensity running to fatigue may increase patellofemoral joint injury risk, but may not be a mechanism for tibial or Achilles tendon overuse injury development.

Optimising the Early-Stage Rehabilitation Process Post-ACL Reconstruction.

Outcomes following anterior cruciate ligament reconstruction (ACLR) need improving, with poor return-to-sport rates and a high risk of secondary re-injury. There is a need to improve rehabilitation strategies post-ACLR, if we can support enhanced patient outcomes. This paper discusses how to optimise the early-stage rehabilitation process post-ACLR. Early-stage rehabilitation is the vital foundation on which successful rehabilitation post-ACLR can occur. Without high-quality early-stage (and pre-operative) rehabilitation, patients often do not overcome major aspects of dysfunction, which limits knee function and the ability to transition through subsequent stages of rehabilitation optimally. We highlight six main dimensions during the early stage: (1) pain and swelling; (2) knee joint range of motion; (3) arthrogenic muscle inhibition and muscle strength; (4) movement quality/neuromuscular control during activities of daily living (5) psycho-social-cultural and environmental factors and (6) physical fitness preservation. The six do not share equal importance and the extent of time commitment devoted to each will depend on the individual patient. The paper provides recommendations on how to implement these into practice, discussing training planning and programming, and suggests specific screening to monitor work and when the athlete can progress to the next stage (e.g. mid-stage rehabilitation entry criteria).

Experimentally induced pain increases absolute but not relative errors and reduces variability in joint repositioning of the knee joint in healthy participants.

BACKGROUND: Joint position sense (JPS) plays an important role in knee joint function. Despite the possible influence of pain on the proprioceptive system, the effects of experimental muscle pain on knee JPS have not been studied. OBJECTIVES: To investigate if experimentally induced muscle pain affects knee JPS in healthy participants. METHODS: Measurements of knee JPS were conducted before and after the injection of 5.8% sterile hypertonic saline in the vastus medialis muscle of 26 healthy physically active adults. Knee JPS was assessed through a passive/active repositioning paradigm in target angles of 15°, 45° and 60° using an isokinetic dynamometer. Absolute and relative angular errors were calculated. The coefficient of variation analysis was used to assess differences in the angles' variability during the repositioning task. RESULTS: Absolute angular error increased in all three angles following experimentally induced pain. The difference was statistically significant at 45° (p = 0.003, d = 0.6) and 15° (p = 0.047, d = 0.4) but not at 60° (p = 0.064, d = 0.4). Relative error did not show directional bias at 45° (p = 0.272, d = 0.2), 15° (p = 0.483, d = 0.1) or 60° (p = 0.091, d = 0.3). The coefficient of variation analysis revealed a statistically significant reduction in variability at angles of 60° (p = 0.002, d = 0.7) and 15° (p = 0.031, d = 0.4) after the pain intervention. CONCLUSION: The presence of experimentally induced muscle pain affects the ability of healthy participants to accurately reposition the knee at two angles of knee flexion and reduces movement variability during the repositioning task. Further research is required to determine if these deficits also impact patients with clinical knee pain.