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We present a procedure for performing an ANOVA test on functional data, including pairwise group comparisons. in a Scheff´e-like perspective. The test is based on the Interval Testing Procedure, and it selects intervals where the groups significantly differ. The procedure is applied on the 3D kinematic motion of the knee joint collected during a functional task (one leg hop) performed by three groups of individuals.

Motivated by the analysis of the dependence of knee movement patterns during functional tasks on subject-specific covariates, we introduce a distribution-free procedure for testing a functional-on-scalar linear model with fixed effects. The procedure does not only test the global hypothesis on the entire domain but also selects the intervals where statistically significant effects are detected. We prove that the proposed tests are provided with an asymptotic control of the intervalwise error rate, that is, the probability of falsely rejecting any interval of true null hypotheses. The procedure is applied to one-leg hop data from a study on anterior cruciate ligament injury. We compare knee kinematics of three groups of individuals (two injured groups with different treatments and one group of healthy controls), taking individual-specific covariates into account.

Background: Consequences of stroke frequently comprise reduced movement ability of the upper extremity (UE) and subsequent long-term disability. Clinical scales are used to monitor and evaluate rehabilitation but are often insufficient, while technological advances in 3D motion capture provide detailed kinematics to more objectively quantify and interpret movement deficits. Objectives: To provide a comprehensive overview of research using kinematic movement analysis of the UE in individuals post-stroke with focus on objectives, methodology and findings while highlighting clinical implications and future directions. Major Findings: A literature search yielded 93 studies categorised into four groups: comparative (healthy, stroke, task condition), intervention (clinical trials), methodological and longitudinal. The majority of studies used optoelectronic systems, investigated discrete reaching and involved mainly individuals with moderate or mild stroke impairment in chronic stage. About 80% of the studies were published after year 2004. Speed-related variables were most frequently addressed followed by smoothness indicators, joint angles and trunk displacement. Movements in the hemiparetic side are generally slower, less smooth and show a compensatory movement pattern. Task specificity is crucial for kinematic outcomes. Tables summarising the main characteristics, objectives and results of all included studies are provided. Conclusions: There is still a lack of studies addressing reliability and responsiveness and involving more complex, everyday UE tasks with ecological validity. To facilitate the use of UE kinematic movement analysis in clinics, a research-based simpler data handling with pre-defined output for the results, as commonly used in gait analysis, is warranted.

This study investigates the cerebellar contribution to reactive grip control by examining differences between (22-48 years) subjects with focal cerebellar lesion due to ischaemic stroke (CL) and healthy subjects (HS). The subjects used a pinch grip to grasp and restrain an instrumented handle from moving when it was subject to unpredictable load forces of different rates (2, 4, 8, 32 N/s) or amplitudes (1, 2, 4 N). The hand ipsilateral to the lesion of the cerebellar subjects showed delayed and more variable response latencies, e.g., 278 +/- 162 ms for loads delivered at 2 N/s, compared to HS 180 +/- 53 ms (P = 0.005). The CL also used a higher pre-load grip force with the ipsilateral hand, 1.6 +/- 0.8 N, than the HS, 1.3 +/- 0.6 N (P = 0.017). In addition, the contralateral hand in subjects with unilateral cerebellar stroke showed a delayed onset of the grip response compared to HS. Cerebellar lesions thus impair the reactive grip control both in the ipsilateral and contralateral hand.

Objective: To systematically review and summarise the evidence for the effects of neuromuscular training compared with any other therapy (conventional training/sham) on knee proprioception following anterior cruciate ligament (ACL) injury.

Design: Systematic Review.

Data sources: PubMed, CINAHL, SPORTDiscus, AMED, Scopus and Physical Education Index were searched from inception to February 2020.

Eligibility criteria: Randomised controlled trials (RCTs) and controlled clinical trials investigating the effects of neuromuscular training on knee-specific proprioception tests following a unilateral ACL injury were included.

Data extraction and synthesis: Two reviewers independently screened and extracted data and assessed risk of bias of the eligible studies using the Cochrane risk of bias 2 tool. Overall certainty in evidence was determined using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) tool.

Results: Of 2706 articles retrieved, only 9 RCTs, comprising 327 individuals with an ACL reconstruction (ACLR), met the inclusion criteria. Neuromuscular training interventions varied across studies: whole body vibration therapy, Nintendo-Wii-Fit training, balance training, sport-specific exercises, backward walking, etc. Outcome measures included joint position sense (JPS; n=7), thresholds to detect passive motion (TTDPM; n=3) or quadriceps force control (QFC; n=1). Overall, between-group mean differences indicated inconsistent findings with an increase or decrease of errors associated with JPS by ≤2°, TTDPM by ≤1.5° and QFC by ≤6 Nm in the ACLR knee following neuromuscular training. Owing to serious concerns with three or more GRADE domains (risk of bias, inconsistency, indirectness or imprecision associated with the findings) for each outcome of interest across studies, the certainty of evidence was very low.

Conclusions: The heterogeneity of interventions, methodological limitations, inconsistency of effects (on JPS/TTDPM/QFC) preclude recommendation of one optimal neuromuscular training intervention for improving proprioception following ACL injury in clinical practice. There is a need for methodologically robust RCTs with homogenous populations with ACL injury (managed conservatively or with reconstruction), novel/well-designed neuromuscular training and valid proprioception assessments, which also seem to be lacking.

PROSPERO registration number CRD42018107349.

Efficient neuromuscular coordination of the thigh muscles is crucial in maintaining dynamic knee stability and thus reducing anterior cruciate ligament (ACL) injury/re-injury risk. This cross-sectional study measured electromyographic (EMG) thigh muscle co-contraction patterns during a novel one-leg double-hop test among individuals with ACL reconstruction (ACLR; n = 34), elite athletes (n = 22) and controls (n = 24). Participants performed a forward hop followed by a 45° unanticipated diagonal hop either in a medial (UMDH) or lateral direction (ULDH). Medial and lateral quadriceps and hamstrings EMG were recorded for one leg (injured/non-dominant). Quadriceps-to-Hamstring (Q:H) ratio, lateral and medial Q:H co-contraction indices (CCIs), and medial-to-lateral Q:H co-contraction ratio (CCR; a ratio of CCIs) were calculated for three phases (100 ms prior to landing, initial contact [IC] and deceleration phases) of landing. We found greater activity of the quadriceps than the hamstrings during the IC and deceleration phases of UMDH/ULDH across groups. However, higher co-contraction of medial rather than lateral thigh muscles during the deceleration phase of landing was found; if such co-contraction patterns cause knee adduction, a putative mechanism to decrease ACL injury risk, during the deceleration phase of landing across groups warrants further investigation.

Unanticipated land-and-cut maneuvers might emulate lower limb mechanics associated with anterior cruciate ligament (ACL) injury. Reliability studies on landing mechanics of such maneuvers are however lacking. This study investigated feasibility and within-session reliability of landing mechanics of a novel one-leg double-hop test, mimicking a land-and-cut maneuver, in individuals with ACL reconstruction (ACLR). Our test comprised a forward hop followed by a diagonal hop in either of two directions (medial/lateral) under anticipated and unanticipated conditions. Twenty individuals with a unilateral ACLR (aged 24.2 ± 4.2 years, 0.7-10.8 years post-surgery) performed three successful hops/direction per leg. We determined reliability (intraclass correlation coefficient [ICC]) and agreement (standard error of measurement [SEM]) of 3-dimensional hip and knee angles and moments during the deceleration phase of the land-and-cut maneuver (vulnerable for non-contact ACL injuries). Mean success rate for unanticipated hops was 71-77% and for anticipated hops 91-95%. Both limbs demonstrated moderate-excellent reliability (ICC 95% confidence intervals: 0.50-0.99) for almost all hip and knee peak angles and moments in all planes and conditions, with a few exceptions: poor-good reliability for hip and knee frontal and/or transverse plane variables, especially for lateral diagonal hops. The SEMs were ≤5° and ≤0.23 N·m/kg·m for most peak angles and moments, respectively. Our test seems feasible and showed satisfactory reliability for most hip and knee angles and moments; however, low knee abduction and internal rotation angles and moments, and moderate reliability of these moments deserve consideration. The test appears to challenge dynamic knee control and may prove valuable in evaluation during knee rehabilitation.

Despite a vast literature on one-leg hops and cutting maneuvers assessing knee control pre/post-injury of the anterior cruciate ligament (ACL), comprehensive and reliable tests performed under unpredictable conditions are lacking. This study aimed to: (1) assess the feasibility of an innovative, knee-challenging, one-leg double-hop test consisting of a forward hop followed by a diagonal hop (45°) performed medially (UMDH) or laterally (ULDH) in an unanticipated manner; and (2) determine within- and between-session reliability for 3-dimensional hip and knee kinematics and kinetics of these tests. Twenty-two healthy women (22.3 ± 3.3 years) performed three successful UMDH and ULDH, twice 1–4 weeks apart. Hop success rate was 69–84%. Peak hip and knee angles demonstrated moderate to excellent within-session reliability (intraclass correlation coefficient [ICC] 95% confidence interval [CI]: 0.67–0.99, standard error of measurement [SEM] ≤  3°) and poor to excellent between-session reliability (ICC CI: 0.22–0.94, SEM ≤ 3°) for UMDH and ULDH. The smallest real difference (SRD) was low (≤ 5°) for nearly all peak angles. Peak hip and knee moments demonstrated poor to excellent reliability (ICC CI: 0–0.97) and, in general, moments were more reliable within-session (SEM ≤ 0.14 N.m/kg.m, both directions) than between-session (SRD ≤ 0.43 N.m/kg.m). Our novel test was feasible and, in most but not all cases, provided reliable angle estimates (within-session > between-session, both directions) albeit less reliable moments (within-session > between-session, both directions). The relatively large hip and knee movements in the frontal and transverse planes during the unanticipated hops suggest substantial challenge of dynamic knee control. Thus, the test seems appropriate for evaluating knee function during ACL injury rehabilitation.

BACKGROUND: Most young adults and adolescents in the United Arab Emirates (UAE) do not meet the established internationally recommended physical activity levels per day. The Arab Teen Lifestyle Study (ATLS) physical activity questionnaire has been recommended for measuring self-reported physical activity of Arab adolescents and young adults (aged 14 years to mid-twenties). The first version of the ATLS has been validated with accelerometers and pedometers (r ≤ 0.30). The revised version of the questionnaire (ATLS-2, 2021) needs further validation. The aim of this study was to validate the self-reported subjective sedentary and physical activity time of the ATLS-2 (revised version) physical activity questionnaire with that of Fibion accelerometer-measured data.

METHODS: In this cross-sectional study, 131 healthy adolescents and young adults (aged 20.47 ± 2.16 [mean ± SD] years (range 14-25 years), body mass index 23.09 ± 4.45 (kg/m2) completed the ATLS-2 and wore the Fibion accelerometer for a maximum of 7 days. Participants (n = 131; 81% non-UAE Arabs (n = 106), 13% Asians (n = 17) and 6% Emiratis (n = 8)) with valid ATLS-2 data without missing scores and Fibion data of minimum 10 h/day for at least 3 weekdays and 1 weekend day were analyzed. Concurrent validity between the two methods was assessed by the Spearman rho correlation and Bland-Altman plots.

RESULTS: The questionnaire underestimated sedentary and physical activity time compared to the accelerometer data. Only negligible to weak correlations (r ≤ 0.12; p > 0.05) were found for sitting, walking, cycling, moderate intensity activity, high intensity activity and total activity time. In addition, a proportional/systematic bias was evident in the plots for all but two (walking and moderate intensity activity time) of the outcome measures of interest.

CONCLUSIONS: Overall, self-reported ATLS-2 sedentary and physical activity time had low correlation and agreement with objective Fibion accelerometer measurements in adolescents and young adults in the UAE. Therefore, sedentary and physical activity assessment for these groups should not be limited to self-reported measures.

Introduction: An anterior cruciate ligament (ACL) injury affects knee proprioception and sensorimotor control and might contribute to an increased risk of a second ACL injury and secondary knee osteoarthritis. Therefore, there is a growing need for valid, reliable and responsive knee proprioception tests. No previous study has comprehensively reviewed all the relevant psychometric properties (PMPs) of these tests together. The aim of this review protocol is to narrate the steps involved in synthesising the evidence for the PMPs of specific knee proprioception tests among individuals with an ACL injury and knee-healthy controls.

Methods and analysis: The Preferred Reporting Items for Systematic reviews and Meta-Analyses will be followed to report the review. A combination of four conceptual groups of terms-(1) construct (knee proprioception), (2) target population (healthy individuals and those with an ACL injury managed conservatively or with a surgical reconstruction), (3) measurement instrument (specific knee proprioception tests) and (4) PMPs (reliability, validity and responsiveness)-will be used for electronic databases search. PubMed, AMED, CINAHL, SPORTDiscus, Web of Science, Scopus, the Cochrane Central Register of Controlled Trials and ProQuest will be searched from their inception to November 2018. Two reviewers will independently screen titles, abstracts and full text articles, extract data and perform risk of bias assessment using the updated COnsensus-based Standards for the selection of health Measurement INstruments risk of bias checklist for the eligible studies. A narrative synthesis of the findings and a meta-analysis will be attempted as appropriate. Each PMP of knee proprioception tests will be classified as 'sufficient', 'indeterminate' or 'insufficient'. The overall level of evidence will be ascertained using an established set of criteria.

Ethics and dissemination: Ethical approval or patient consent is not required for a systematic review. The review findings will be submitted as a series of manuscripts for peer-review and publication in scientific journals.

BACKGROUND: A major problem with rehabilitation interventions for neck pain is that the condition may have multiple causes, thus a single treatment approach is seldom efficient. The present study protocol outlines a single blinded randomised controlled trial evaluating the effect of tailored treatment for neck-shoulder pain. The treatment is based on a decision model guided by standardized clinical assessment and functional tests with cut-off values. Our main hypothesis is that the tailored treatment has better short, intermediate and long-term effects than either non-tailored treatment or treatment-as-usual (TAU) on pain and function. We sub-sequentially hypothesize that tailored and non-tailored treatment both have better effect than TAU.

METHODS: 120 working women with minimum six weeks of nonspecific neck-shoulder pain aged 20-65, are allocated by minimisation with the factors age, duration of pain, pain intensity and disability in to the groups tailored treatment (T), non-tailored treatment (NT) or treatment-as-usual (TAU). Treatment is given to the groups T and NT for 11 weeks (27 sessions evenly distributed). An extensive presentation of the tests and treatment decision model is provided. The main treatment components are manual therapy, cranio-cervical flexion exercise and strength training, EMG-biofeedback training, treatment for cervicogenic headache, neck motor control training. A decision algorithm based on the baseline assessment determines the treatment components given to the each participant of T- and NT-groups. Primary outcome measures are physical functioning (Neck Disability Index) and average pain intensity last week (Numeric Rating Scale). Secondary outcomes are general improvement (Patient Global Impression of Change scale), symptoms (Profile Fitness Mapping neck questionnaire), capacity to work in the last 6 weeks (quality and quantity) and pressure pain threshold of m. trapezius. Primary and secondary outcomes will be reported for each group with effect size and its precision.

DISCUSSION: We have chosen not to include women with psychological ill-health and focus on biomedical aspects of neck pain. Future studies should aim at including psychosocial aspects in a widened treatment decision model. No important adverse events or side-effects are expected.

Trial registration: Current Controlled Trials registration ISRCTN49348025.

Introduction: People with anterior cruciate ligament (ACL) reconstruction (ACLR) are at high risk of sustaining a graft rupture and/or contra-lateral ACL injury. The main factors that may predispose individuals for subsequent ACL injuries are, however, not established. To reduce the risk of reinjuries, it is of particular interest to identify modifiable risk-factors, for instance, those related to sensorimotor control which are responsive to training. The aim of the current study protocol is to present the design of our prospective cohort study STOP Graft Rupture investigating sensorimotor function as predictors for graft rupture, contra-lateral ACL injury and/or failure to return to sport (RTS) within 3 years following ACLR.

Methods and analysis: We aim to recruit 200 individuals (15–35 years, ~50% women) with ACLR from Norrland University Hospital, Umeå and Lund University Hospital, Lund, Sweden. Participants will be assessed with a comprehensive test battery for sensorimotor muscle function, including hop performance, muscle strength, muscle activation, hip and ankle range of motion and postural orientation as well as patient-reported function 1 year after ACLR (baseline). For a subgroup of individuals (Umeå cohort), 3D kinematics and joint position sense will also be evaluated. At follow-up (≥3 years post-ACLR), the participants will be asked to answer questions related to new ACL injuries to either knee and about RTS. Separate logistic regression models, adjusting for possible confounders, will be used to evaluate the influence of the different sensorimotor predictors on the prospective outcomes (graft rupture, contra-lateral ACL injury, RTS).

Ethics and dissemination: This study was approved by the Swedish Ethical Review Board (Dnr 2016/319 and Dnr 2019-04037). The results will be published in international peer-reviewed scientific journals and presented at clinical and scientific congresses.

Trial registration number: NCT04162613.

Objective: To determine the relative contribution of each of the following aspects: demographics, physical function, and patient-reported outcome measures (PROMs), including both physical and psychological constructs, to return to sport (RTS) (any level) one-year post anterior cruciate ligament reconstruction (ACLR). Design: Cross-sectional cohort study.

Methods: We included data for 143 participants (73 women, mean (SD) age 24 (5.8) years) ∼ one-year post-ACLR. Data comprised demographics, physical function (hop performance, hip and knee peak torque) and PROMs (Knee Osteoarthritis Outcome Score subscales, perceived stress, and ACL Return to Sport after Injury scale (ACL-RSI)). We then used a Z-normalized multivariable logistic regression model to establish the relative contribution of factors associated with RTS.

Results: Sixty-four (45%) of the participants had returned to sport at one year post-ACLR. In the regression model, greater hip abduction peak torque (OR = 1.70, 95% CI; 1.01 to 2.84) and greater psychological readiness to RTS (OR = 2.32, 95% CI; 1.30 to 4.12) were the only variables associated with RTS (R2 = 0.352).

Conclusions: The significant contribution of hip abduction strength and psychological readiness to RTS was still relatively small, suggesting other potential factors explaining RTS which may not be captured by common RTS criteria.

Background: Sports function and psychological readiness to return to sports (RTS) are important outcomes when evaluating rehabilitation after anterior cruciate ligament reconstruction (ACLR). It is, however, unclear which specific factors contribute most to these outcomes.

Purpose: To determine associations between demographic characteristics, objective measurements of physical function, patient-reported outcome measure scores, sports-related function assessed with the Knee injury and Osteoarthritis Outcome Score (KOOS) Sport and Recreation subscale, and psychological readiness to RTS assessed with the Anterior Cruciate Ligament–Return to Sport after Injury (ACL-RSI) scale at 1 year after ACLR.

Study Design: Cross-sectional study; Level of evidence, 3. Methods: At a mean of 12.5 ± 2.0 months after ACLR, 143 participants (50.3% female), with a mean age of 25.0 ± 5.7 years, were assessed for demographic characteristics, physical factors (hop performance, muscle strength, ankle and hip range of motion), and psychological factors (KOOS Pain and Symptoms subscales, Perceived Stress Scale, fear of reinjury) as well as the KOOS Sport and Recreation subscale and ACL-RSI scale. Backward linear regression models were used to evaluate factors associated with sports function and psychological readiness to RTS.

Results: Lower isokinetic knee extension peak torque (limb symmetry index) (B = 18.38 [95% CI, 3.01-33.75]), lower preinjury activity level (B = 2.00 [95% CI, 0.87-3.14]), greater knee pain (B = 0.90 [95% CI, 0.70-1.10]), shorter time between injury and reconstruction (B = 0.16 [95% CI, 0.05-0.26]), and greater fear of reinjury (B = 0.11 [95% CI, 0.01-0.20]) were associated with a worse KOOS Sport and Recreation subscore (R² = 0.683). A shorter hop distance (B = 0.15 [95% CI, 0.00-0.29]) was associated with a lower ACL-RSI score (R² = 0.245).

Conclusion: A combination of knee muscle strength, activity level, knee pain, timing of surgery, and fear of reinjury accounted for approximately 70% of the variation in sports function at 1 year after ACLR. In contrast, there was only 1 weak association between physical function and psychological readiness to RTS at this time point. Thus, factors associated with current sports function are much better known than features related to psychological readiness to RTS.

Background: The risk of sustaining a graft rupture after anterior cruciate ligament reconstruction (ACLR) is high. Contributing risk factors are, however, still not clearly identified.

Objective: The aim of this systematic review was to identify and quantify risk factors for graft rupture after ACLR.

Methods: A systematic review with meta-analysis (PROSPERO CRD42020140129) based on PRISMA guidelines was performed. MEDLINE, CINAHL and EMBASE were searched from inception to September 2021. Prospective and retrospective studies addressing risk factors for graft rupture after ACLR in males/females of all ages were considered. Meta-analyses using a random effect model (effect measure: odds ratio [OR] with 95% confidence interval [CI]) were performed. The GRADE tool was used to assess evidence quality.

Results: Following full-text screening of 310 relevant papers, 117 were eventually included, incorporating up to 133,000 individuals in each meta-analysis. Higher Tegner activity level (≥ 7 vs < 7) at primary injury (OR 3.91, 95% CI 1.69–9.04), increased tibial slope (degrees) (OR 2.21, 95% CI 1.26–3.86), lower psychological readiness to return to sport (RTS) (OR 2.18, 95% CI 1.32–3.61), early surgery (< 12 vs ≥ 12 months) (OR 1.87, 95% CI 1.58–2.22), RTS (pre-injury level) (OR 1.87, 95% CI 1.21–2.91) and family history of ACL injury (OR 1.76, 95% CI 1.34–2.31) were all associated with increased odds of graft rupture. Higher age (OR 0.47, 95% CI 0.39–0.59), female sex (OR 0.88, 95% CI 0.79–0.98), fewer self-reported knee symptoms pre-reconstruction (OR 0.81, 95% CI 0.69–0.95) and concomitant cartilage injuries (OR 0.70, 95% CI 0.62–0.79) instead decreased the odds. Meta-analysis revealed no association between body mass index, smoking, joint laxity, RTS time, knee kinematics, muscle strength or hop performance and graft rupture.

Conclusion: Conspicuous risk factors for graft rupture were mainly sports and hereditary related. Few studies investigated function-related modifiable factors or included sports exposure data.

Background: There is limited knowledge about which risk factors that contribute to the high numbers of contra-lateral anterior cruciate ligament (C-ACL) injury after primary ACL injury.

Objective:  To systematically review intrinsic risk factors for sustaining a C-ACL injury.

Design: A systematic review with meta-analysis according to the PRISMA guidelines. Four databases (MEDLINE, CINAHL, EMBASE, Sport Discus) were searched from inception to January 2020. Meta-analyses were performed and expressed as odds ratios (OR).

Setting: The included studies describe a variety of sport settings and activity levels.

Participants: The review comprises studies including males and/or females of any age with ACL injury.

Assessment of Risk Factors: The review comprises longitudinal studies investigating any intrinsic risk factor for future C-ACL injury.

Main Outcome Measurements: C-ACL injury

Results: Thirty-five moderate-to-high quality studies were eligible for meta-analysis, including up to ~59 000 individuals. The following factors all independently increased the odds of sustaining a C-ACL: Returning to a high activity level (OR: 3.26, 95% CI: 2.10–5.06), BMI < 25 (OR: 2.73, 95% CI: 1.73–4.36), Age ≤ 18 years (OR: 2.42, 95% CI: 1.51–3.88), Family history of ACL injury (OR: 2.07, 95% CI: 1.54–2.80), Primary ACL reconstruction performed ≤ 3 months post injury (OR: 1.65, 95% CI: 1.32–2.06), Female sex (OR: 1.35, 95% CI: 1.14–1.61) and Concomitant meniscal injury (OR 1.21, 95% CI: 1.03–1.42). There were no associations between the odds of sustaining a C-ACL injury and Smoking status, Pre-injury activity level, Playing soccer compared to other sports or Timing of return to sport.

Conclusions: Demographic factors such as female sex, young age and family history of ACL injury, as well as early reconstruction and returning to a high activity level all contribute to the risk of sustaining a C-ACL injury. Studies on modifiable sensorimotor risk factors are warranted.

Background: Underlying factors contributing to increased risk of graft rupture after anterior cruciate ligament reconstruction (ACLR) are not well described.

Objective: To systematically review intrinsic risk factors for sustaining a graft rupture.

Design: A systematic review with meta-analysis according to the PRISMA guidelines. Four databases (MEDLINE, CINAHL, EMBASE, Sport Discus) were searched from inception to January 2020. Meta-analyses (random effect model) were performed and expressed as odds ratios (OR).

Setting: The included studies describe a variety of sport settings and activity levels.

Participants: The review comprises studies including males and/or females of any age who have had ACLR.

Assessment of Risk Factors: All longitudinal studies investigating any intrinsic risk factor for future graft rupture were included.

Main Outcome Measurements: Graft rupture.

Results: Seventy-seven studies were eligible for meta-analysis. The following factors all independently increased the odds of sustaining a graft rupture after ACLR: Age ≤ 18 years (OR: 3.87, 95% CI: 2.32–6.46), higher pre-primary injury activity level (OR: 2.43, 95% CI: 1.56–3.82), family history of ACL injury (OR: 1.98, 95% CI: 1.50–2.62), returning to a high activity level (OR: 1.87, 95% CI: 1.11–3.15), and increased lateral tibial slope (OR: 1.64, 95% CI: 1.13–2,38). None of the following factors were found to be associated with future graft rupture; sex, smoking status, generalized joint laxity, timing of surgery or return to sport (RTS), playing soccer compared to other sports, hop performance at time of RTS or concomitant meniscal or collateral ligament injuries.

Conclusions: Young age, family history of ACL injury, high tibial slope and previous and current high activity level should be considered when screening for increased risk of graft rupture following ACLR. Future studies on the possible role of sensorimotor factors, e.g., muscle activation and/or strength and proprioception for future graft ruptures are warranted.

Background: The risk of sustaining a contra-lateral anterior cruciate ligament (C-ACL) injury after primary unilateral ACL injury is high. C-ACL injury often contributes to a further decline in function and quality of life, including failure to return to sport. There is, however, very limited knowledge about which risk factors that contribute to C-ACL injury.

Objective: To systematically review instrinsic risk factors for sustaining a C-ACL injury.

Methods: A systematic review with meta-analysis was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Four databases (MEDLINE, CINAHL, EMBASE, Sport Discus) were searched from inception to January 2020. Inclusion criteria were prospective or retrospective studies investigating any intrinsic risk factor for future C-ACL injury. Meta-analysis was performed and expressed as odds ratios (OR) if two or more articles assessed the same risk factor.

Results: 44 moderate-to-high quality studies were eventually included in this review, whereof 35 studies were eligible for meta-analysis, including up to 59 000 individuals. We identified seven factors independently increasing the odds of sustaining a C-ACL injury (in order of highest to lowest OR): (1) returning to a high activity level (OR 3.26, 95% CI 2.10–5.06); (2) Body Mass Index < 25 (OR 2.73, 95% CI 1.73–4.36); (3) age ≤ 18 years (OR 2.42, 95% CI 1.51–3.88); (4) family history of ACL injury (OR 2.07, 95% CI 1.54–2.80); (5) primary ACL reconstruction performed ≤ 3 months post injury (OR 1.65, 95% CI: 1.32–2.06); (6) female sex (OR 1.35, 95% CI 1.14–1.61); and (7) concomitant meniscal injury (OR 1.21, 95% CI 1.03–1.42). The following two factors were associated with decreased odds of a subsequent C-ACL injury: 1) decreased intercondylar notch width/width of the distal femur ratio (OR 0.43, 95% CI 0.25–0.69) and 2) concomitant cartilage injury (OR 0.83, 95% CI 0.69–1.00). There were no associations between the odds of sustaining a C-ACL injury and smoking status, pre-injury activity level, playing soccer compared to other sports or timing of return to sport. No studies of neuromuscular function in relation to risk of C-ACL injury were eligible for meta-analysis according to our criteria.

Conclusion: his review provides evidence that demographic factors such as female sex, young age (≤ 18 years) and family history of ACL injury, as well as early reconstruction and returning to a high activity level increase the risk of C-ACL injury. Given the lack of studies related to neuromuscular factors that may be modifiable by training, future studies are warranted that investigate the possible role of factors such as dynamic knee stability and alignment, muscle activation and/or strength and proprioception as well as sport-specific training prior to return-to-sport for C-ACL injuries.

The ActivPAL device is a well-established physical activity monitor for assessment of physical activity. AIM: To investigate test-retest reliability of step counts and establish minimal detectable changes (MDC) in step count to account for intra device error over time in various physical activities. METHODS: Healthy participants (n=24, age range, 19-28 years) performed activities on two occasions, 1 week apart, in a laboratory setting; self-paced floor walking, treadmill walking at three different speeds (3.2 km/h, 4.5 km/h and 4.5 km/h with incline), treadmill jogging (8.0 km/h), stair walking and cycling on an exercise bike at three speeds (45 rpm, 60 rpm and 75 rpm). Relative reliability was calculated using intraclass correlation coefficient (ICC) and Spearman correlation. Absolute reliability was assessed using standard error of measurement (SEM) and coefficient of repeatability (CR). RESULTS: The ActivPAL showed high to very high relative reliability for treadmill walking at all speeds and stair walking, while self-paced normal floor walking showed moderate reliability. The absolute reliability was the best for treadmill walking activities, slightly increased for self-paced walking, followed by stair walking and jogging. The use of activity monitors during cycling has been questioned and our results confirm a low absolute and relative reliability. MDC values varied according to the type of activity e.g. treadmill walking 4.5 km/h (10 steps), walking on the floor (45 steps). Data loss in this study (10-13%) was higher than previously reported. CONCLUSIONS: The ActivPAL is reliable for treadmill walking, jogging and self-paced walking. MCD varies according to the activity and should be considered when establishing true change over time.

Purpose: The aim of the present study was to examine hand function and disability in persons with Charcot-Marie-Tooth disease (CMT) and to evaluate the possible correlations between hand function and disability.

Methods: Nine male, 11 female (24-73 yrs) persons with CMT in northern Sweden and a matched control group of 18 men, 22 women (21-73 yrs) participated in the study. Measurements applied were tests of dexterity (Box and Block Test; Nine-Hole Peg test), grip strength (Grippit®), tactile gnosis (Shape Texture Identification test) and upper-limb disability (Disabilities of the Arm Shoulder and Hand questionnaire, DASH).

Results: Hand function in CMT was reduced (p<0.001) to about 60% of normal, as indicated by each of the separate outcome measures as well as by a constructed summary index of hand function. DASH score median was 38.8 (range 0-66.7) and was clearly related to hand function (r=0.64-0.83).

Conclusion: Reduced hand function in CMT was found at different dimensions according to the International Classification of Functioning, Disability and Health (ICF). We suggest that DASH can be used in persons with CMT though clinicians should be aware that patients might score lower than expected, possibly due to a long process of adaptation when learning to live with a slowly progressive disease.

The aim was to improve the control of reaching movements in prematurely born children with impaired coordination. Fifteen 6-year-old prematurely born children (birth weight < 1500 g) practised mouse-controlled computer games daily for 4 weeks. In addition, as a control condition, each child practised trampoline jumping for an equally long perios. The outcome was measured in terms of: (1) computer game skill, (2) kinematic analysis of planar reaching movements on a digitizing tablet, and (3) motor performance measured with the Movement ABC. After intervention, all the assessments used showed an improvement although only the skill in performing the computer game was clearly related to the type of intervention. Lack of tight correlation between computer game practice and performance on the digitizing tablet might be due to minor but crucial differences in control aspects between the task. The present results indicate that the expectation of transfer even to every similar tasks should be low. The findings thus support a task-specific approach to practice, while corroborating the positive impact of non-specific intervention.

Polymorphisms in VEGFA and KDR encoding proteins have been associated with anterior cruciate ligament (ACL) injury risk. We leveraged a collective sample from Sweden, Poland, and Australia to investigate the association of functional polymorphisms in VEGFA and KDR with susceptibility to ACL injury risk. Using a case–control genetic association approach, polymorphisms in VEGFA and KDR were genotyped and haplotypes inferred from 765 controls, and 912 cases clinically diagnosed with ACL rupture. For VEGFA, there was a significant overrepresentation of the rs2010963 CC genotype (p = 0.0001, false discovery rate [FDR]: p = 0.001, odds ratio [OR]: 2.16, 95% confidence interval [CI]: 1.47–3.19) in the combined ACL group (18%) compared to the combined control group (11%). The VEGFA (rs699947 C/A, rs1570360 G/A, rs2010963 G/C) A-A-G haplotype was significantly (p = 0.010, OR: 0.85, 95% CI: 0.69–1.05) underrepresented in the combined ACL group (23%) compared to the combined control group (28%). In addition, the A-G-G construct was significantly (p = 0.036, OR: 0.81, 95% CI: 0.64–1.02) underrepresented in the combined ACL group (12%) compared to the combined CON group (16%). Our findings support the association of the VEGFA rs2010963 CC genotype with increased risk and (ii) the VEGFA A-A-G haplotype with a reduced risk, and are in alignment with the a priori hypothesis. Collectively identifying a genetic interval within VEGFA to be implicated in ACL risk modulation and highlight further the importance of vascular regulation in ligament biology.

Purpose: Individual perspectives of long-term consequences decades after anterior cruciate ligament (ACL) injury are unexplored. We addressed experiences and the impact on life of former athletes >20 years post-ACL injury.

Methods: Individual interviews, analysed using Grounded Theory, were conducted with 18 persons injured mainly during soccer 20–29 years ago.

Results: A theoretical model was developed with the core category Re-orientation towards acceptance, overarching three categories illustrating the long-term process post-injury. Initially the persons felt like disaster had struck; their main recall was strong pain followed by reduced physical ability and fear of movement and re-injury. In the aftermaths of injury, no participant reached the pre-injury level of physical activity. Over the years, they struggled with difficult decisions, such as whether to partake or refrain from different physical activities, often ending-up being less physically active and thereby gaining body weight. Fear of pain and re-injury was however perceived mainly as psychological rather than resulting from physical limitations. Despite negative consequences and adjustments over the years, participants still found their present life situation manageable or even satisfying.

Conclusion: ACL injury rehabilitation should support coping strategies e.g., also related to fear of re-injury and desirable physical activity levels, also with increasing age.

IMPLICATIONS FOR REHABILITATION

More than 20 years after the ACL injury, the individuals despite re-orientation towards acceptance and a settlement with their life situation, still had fear of both pain and re-injury of the knee, with concerns about physical activity and gaining of body weight. Patients with ACL injury may need better individual guidance and health advice on how to remain physically active, to find suitable exercises and to maintain a healthy body weight. Education related to pain, treatment choices, physical activity, injury mechanisms in participatory discussions with the patient about the ACL injury may be beneficial early in the rehabilitation process to avoid catastrophizing and avoidance behaviour. ACL injury rehabilitation needs to address coping strategies incorporating the psychological aspects of suffering an ACL injury, including fear of movement/secondary injury, in order to support return-to-sport and/or re-orientation over time.

Introduction: There is an increase of age related diseases such as hip joint arthritis, something that is often treated with hip replacement surgery. The aim of this study was to quantify movement function and its effect on quality of life in persons treated with hip implant, in comparison to matched asymptomatic controls.

Patients/Materials and Methods: This is an ongoing study, and so far, 2 asymptomatic subjects (CTRL, age 50 ± 13 years, BMI 23 ± 2), and 4 subjects with hip implant (HIP, age 51 ± 15 years, BMI 25 ± 3), have been analyzed. The HIP group received their implant 2.6 ± 1.1 years ago and finished their rehabilitation 1.6 ± 1.1 years ago. Hip dysfunction and Osteoarthritis Outcome Score (HOOS) was used to assess the subject's hip function and its associated problems. A functional calibration (flexion/abduction movements) was done and each subject then performed 5 repetitions of gait (approx. 25 left/right gait cycles). Movement was registered with a custom-developed portable motion sensor system, where each sensor consisted of a tri-axial accelerometer and gyroscope. Sensors were placed on pelvis and each thigh and shank. Further calculations were done in MATLAB (v7.12 R2011a, Mathworks). Cosine rotation matrices were extracted by functional sensor-to- segment-calibration and sensor fusion [1], and hip and knee angles were obtained as Euler angles.

Results: Preliminary results indicated larger range in hip rotation and smaller range of knee flexion during gait in HIP group than in the CTRL group (Fig. 1). HOOS profile (Fig. 2) indicated that hip function during sports (SP) and the general quality of life (QOL) were lower in the HIP group.

Fig. 1. 

Mean and SD of hip and knee angle over 15 gait cycles in one HIP subject (blue) as compared with the CTRL group (black). (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)

Figure optionsFig. 2. 

HOOS profiles in HIP (blue square) and CTRL group (black). (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)

Figure options

Discussion and conclusions: Motion patterns during gait seemed to be negatively affected in subjects with hip implant, even after the rehabilitation program was completed and even though the HOOS profiles indicated a relative good hip function.

Reference

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• J. Favre, B.M. Jolles, O. Siegrist, K. Aminian

• Quaternion-based fusion of gyroscopes and accelerometers to improve 3D angle measurement

Individuals with knee osteoarthritis (OA) commonly demonstrate impaired postural control. We aimed to systematically review psychometric properties of tests that assess postural control in people with knee OA and secondly, to determine domains of postural control measured by these tests. PubMed, CINAHL, Embase and Web of Science databases were searched to January 2019. Two independent review authors screened references according to eligibility criteria. The Consensus-based Standards for the selection of health Measurement Instruments were used to evaluate study methodological quality. Postural control tests identified from included studies were assessed to determine postural control constructs using the Systems Framework for Postural Control identifying nine domains. Following the screening of 2643 references, five cross-sectional studies and one longitudinal study (n = 408) were included. Four studies evaluated reliability, validity or responsiveness of three clinical measures: Community Balance and Mobility Scale, Star Excursion Balance Test and Tinetti Performance Oriented Mobility Assessment. Two assessed reliability or validity of a force platform. Results showed that evidence for reliability, validity and responsiveness of all these postural measures is limited. The most common domain of postural control assessed was ‘static stability’. No study used measures that evaluated all nine postural control domains. Our results highlight limited investigation of psychometric properties specific to postural control in knee OA. The few existing ones have limitations regarding psychometric robustness and completeness regarding different domains of postural control. Future research should focus on verifying the quality of existing tools to evaluate postural control in knee OA for research and clinical purposes.

Background: Sit-to-stand (STS) is a crucial transfer influencing a person's independence in daily activities, as well as safety and quality of life, and is thus vital to evaluate in research and in practice. Clinical STS tests provide single values in seconds or numbers of STS. There is, however, increasing numbers of research papers reporting spatial and temporal kinematic and kinetic process STS data.

Objectives: To provide an overview of research findings from laboratory-based movement analyses regarding phases and determinants of typical STS, characteristics of successful versus failed STS transfers, and finally STS performance in some neurological conditions.

Major Findings: The STS transfer, previously regarded as mainly requiring lower limb muscle strength, is increasingly recognized as a complex transfer skill. Muscle strength, balance, foot position, chair height and the movement strategy are major determinants influencing STS performance. Scaling and timing of momentum generation throughout STS seems critical for success or failure. Sit-to-stand in stroke and Parkinson's disease (PD) is characterized by asymmetry in force generation and difficulties in switching movement direction, respectively. In-depth, knowledge regarding mechanisms of momentum control during STS sub-phases, STS failures, as well as exploration of variability in normal and atypical STS is still lacking.

Conclusions: Recent research based on instrumented movement analyses has generated better understanding of movement control during STS, but the specifics are not yet reflected in clinical assessments. There seems to be a call for clinical tools capturing determinants and process characteristics of the STS transfer for a more comprehensive evaluation in rehabilitation.

In 3D gait analysis, quantification of leg movements is well established, whereas ameasure of armswing has been lacking. Recently, the Arm Posture Score (APS) was introduced to characterize arm movements in children with cerebral palsy, including information from four variables (APS(4)) in the sagittal and frontal planes. A potential limitation of the APS is that it does not include rotational movements and has not yet been evaluated with regard to gait speed. The aims of this study were (i) to investigate the effect on APS of adding two components of arm rotation (APS(6)) and (ii) to determine the influence of gait speed on the APS measures, when applied to non-disabled adults. Forty-two subjects walked 10 m at a selfselected speed (1.34 m/s), and in addition a subgroup of 28 subjects walked at a slowspeed (0.66 m/s) set by a metronome. Data were collected from markers in a whole-body set up and by eight optoelectronic cameras. The results demonstrated significantly higher APS(6) than APS(4) values for both arms, irrespective of gait speed. Speed condition, whether self-selected or slow, had a significant effect on both APS measures. The two additional arm components are suggested to provide relevant information about arm swing during walking. However, APS(6) needs to be implemented in gait analysis of individuals with gait arm pathologies in order to further examine its utility. Werecommend that gait speed should to be taken into account when using APS measures to quantify arm swing during gait. (C) 2014 Elsevier B. V. All rights reserved.

Objective: To investigate the feasibility of a virtual reality exercise intervention within an interdisciplinary rehabilitation programme for persons with chronic neck pain. The effects of the intervention on symptom severity, variables related to chronic neck pain, and patients' experience of exercises were assessed.

Methods: Nine women and 3 men participated in a 6-week virtual reality exercise intervention during an interdisciplinary rehabilitation programme. Symptom severity was rated before and after each session of virtual reality exercise, using questionnaires before and after the interdisciplinary rehabilitation programme, and questions about participants' experiences.Results: Neck pain symptoms increased temporarily during the exercises, but no lasting deterioration was found after the interdisciplinary rehabilitation programme. Depression, pain interference, pain control, sleep and kinesiophobia improved significantly after the programme. Participants experienced that the virtual reality exercises increased motivation to exercise and provided a focus other than pain. However, the equipment was heavy; and exercising was tiring and reminded them of their challenges.

Conclusion: This study indicates that virtual reality exercises as part of an interdisciplinary rehabilitation programme are feasible and safe for patients with chronic neck pain. Pain symptoms may increase temporarily during the exercises. Virtual reality exercises may support participants by increasing motivation to exercise and providing helpful feedback. Further research into the added value of virtual reality exercises in an interdisciplinary rehabilitation programme for patients with chronic neck pain is warranted.

BACKGROUND: Compensatory movement strategies may develop in response to pain to avoid stress on the affected area. Patellofemoral pain is characterised by intermittent periods of pain and the present study addresses whether long-term pain leads to compensatory movement strategies that remain even when the pain is absent. METHOD: Lower extremity kinematics in three dimensions was studied in stair descent in 17 women with patellofemoral and in 17 matched controls. A two-dimensional geometric model was constructed to normalise kinematic data for subjects with varying anthropometrics when negotiating stairs of fixed proportions. RESULTS: There were minor differences in movement patterns between groups. Knee joint angular velocity in the stance leg at foot contact was lower and the movement trajectory tended to be jerkier in the patellofemoral group. The two-dimensional model showed greater plantar flexion in the swing leg in preparation for foot placement in the patellofemoral group. INTERPRETATION: The results indicate that an altered stair descent strategy in the patellofemoral group may remain also in the absence of pain. The biomechanical interpretation presumes that the strategy is aimed to reduce knee joint loading by less knee joint moment and lower impact force.

Sensorimotor deficits, particularly proprioceptive, are often reported following rupture of the anterior cruciate ligament (ACL). High secondary injury rates and long-term negative consequences suggest that these deficits are not properly identified using current assessment methods. We explored a novel obstacle clearance test to evaluate sensorimotor control in individuals following ACL reconstruction (ACLR) and rehabilitation. Thirty-seven post-ACLR individuals, 23 nonathletic asymptomatic controls (CTRL), and 18 elite athletes stepped over a hurdle-shaped obstacle, downward vision occluded, aiming for minimal clearance. Kinematic outcomes (3D motion capture) for the leading and trailing legs, for two unpredictably presented obstacle heights, were categorized into Accuracy: vertical foot clearance and minimal distance from the obstacle; Variability: end-point and hip/knee trajectory; and Symmetry: trunk/hip/knee crossing angles, hip–knee–ankle movement, and velocity curves. Accuracy was worse for CTRL compared with both other groups. ACLR had less leading and trailing vertical foot clearance with their injured compared with their noninjured leg. ACLR and athletes had less crossing knee flexion in their injured/nondominant legs compared with their contralateral leg, both leading and trailing. ACLR showed greater trunk flexion when crossing with their injured leg, both leading and trailing. For the leading leg, ACLR showed greater asymmetry for the hip–knee–ankle velocity curve compared with elite athletes. Trailing leg trajectory variability was lower for ACLR compared with CTRL and athletes for higher obstacles. Clinical significance: Sensorimotor deficits in individuals post-ACLR were reflected by greater asymmetry and less variable (more stereotypical) trajectories rather than limb positioning ability. This consideration should be addressed in clinical evaluations.

Objectives: To evaluate knee joint position sense (JPS) among individuals with anterior cruciate ligament reconstruction (ACLR), cleared for return to sport, and investigate whether JPS errors are associated with outcomes of a functional obstacle clearance test (OC; downward vision occluded).

Design: Cross-sectional.

Setting: Controlled laboratory.

Participants: Thirty-four individuals following ACLR, 23 non-athletic asymptomatic controls (CTRL), 18 athletes (ATH).

Main outcome measures: absolute error (AE) and variable error (VE) for weight-bearing knee JPS (target angles: 40°, 65°); minimal distances of the lower extremity from the obstacle (at any time and vertical clearance; two obstacle heights).

Results: Larger AE (P = 0.023) and VE (P = 0.010) were observed for CTRL compared with ACLR. CTRL also had larger OC distances for the trailing leg compared with ATH (P ≤ 0.046) and greater variability compared to both other groups (P ≤ 0.033). Moderate positive correlations (Rs ≥ 0.408, P ≤ 0.029) were observed between AE for the 40° angle and low-obstacle distances, for the injured ACLR leg.

Conclusions: Knee JPS was worse in less-active individuals rather than following ACLR. Functional assessments like our OC test should complement isolated JPS tests, as they emphasize whole-body coordination and thus constitute more relevant estimations of proprioception.

Background: Psychophysiological consequences often persist following musculoskeletal trauma and can result in vastly decreased quality of life. Re-injury anxiety is particularly common among individuals following anterior cruciate ligament (ACL) injury. Existing assessments of re-injury anxiety are, however, restricted to subjective suboptimal questionnaires, which may result in under-reporting and thus poorer injury management. We propose a novel approach to objectively quantify arousal response to movement-related anxiety. A new experimental paradigm was implemented to induce and record a conditioned electrophysiological response to a sudden perturbation, experienced to be potentially injurious.

Objective: To explore the feasibility of detecting anxiety-associated electrocortical response and to evaluate its discriminative ability between asymptomatic individuals and those who had experienced an ACL injury.

Methods: Physically-active asymptomatic persons and individuals post-ACL reconstruction stood blindfolded on a perturbation platform capable of generating high-acceleration translations (1.5 m/s2). Auditory stimuli were repeatedly presented in four-second intervals, as either low- or high-frequency tones. Half of the high-frequency tones were followed 1.5 seconds later by a destabilizing perturbation in one of eight randomized directions. The two tone conditions were thus termed ‘Neutral’ and ‘Anxiety’, as the high-frequency tone was intended to invoke an arousal response in anticipation of a potential perturbation. Event-related potentials (ERP) were computed for nine electrodes by averaging 100 Neutral and 100 Anxiety trials. Significant ERP components were identified using functional data analysis. Paired difference-waves’ amplitudes (Neutral - Anxiety) were compared between groups.

Results: ERP correlates of anxiety were detected for both groups in frontal and central midline locations, with an observable contingent negative variation (CNV) from 500 ms post-stimulus in Anxiety compared with Neutral trials. This ERP component is reflective of a threat-induced arousal response, associated with attention and expectancy of an anxiety-relevant event. Preliminary data indicate no group differences in CNV amplitudes.

Conclusions: Objective evaluation of an arousal response to movement-related anxiety was found to be feasible, resulting in a threat-induced CNV. Further investigation will elucidate the discriminative power of such an approach to differentiate between individuals with high and low re-injury anxiety, as well as potential associations with existing patient-reported outcome measures.

Psychological consequences often persist following musculoskeletal trauma and can result in vastly decreased quality of life. Re-injury anxiety is reported to hinder return to sports and can itself be a precursor for secondary injuries. Existing assessments of re-injury anxiety are restricted to subjective questionnaires, which may result in under-reporting and thus poorer injury management. In the current study, we introduced an experimental approach to objectively quantify movement-related anxiety using a threat-conditioning paradigm. We aimed to explore the feasibility of such an approach among non-injured persons.

Ten physically-active individuals stood blindfolded on a platform capable of generating high-acceleration translations in eight different directions. Consecutive auditory stimuli were presented (four-second intervals), as either high- (conditioned stimulus; CS⁺) or low- (neutral stimulus; CS^–) tones. Half of the CS⁺ trials were followed by a perturbation in a pseudo-random order. Event-related potentials were computed for nine electrodes by averaging 100 X CS^– and 100 X CS⁺ trials. Significant latencies for CS^– – CS⁺ comparisons were identified using interval-wise testing. Mean-amplitudes for significant intervals were used to detect a channel effect.

Large negative CS+ waveforms were observed from 302-627ms post-stimulus and continuing until the end of the trials, most prominently over frontal and central midline locations (p ≤ 0.025). This effect, inferred as a contingent negative variation wave (CNV), may be reflective of threat-induced arousal response.

Our test paradigm was found to be feasible, with a CNV suggested as a potential biomarker for re-injury anxiety. Further validation is needed, as well as exploring the discriminative power of such an approach between individuals with and without previous injury.

Musculoskeletal trauma often leads to lasting psychological impacts stemming from concerns of future injuries. Often referred to as kinesiophobia or re-injury anxiety, such concerns have been shown to hinder return to physical activity and are believed to increase the risk for secondary injuries. Screening for re-injury anxiety is currently restricted to subjective questionnaires, which are prone to self-report bias. We introduce a novel approach to objectively identify electrocortical activity associated with the threat of destabilising perturbations. We aimed to explore its feasibility among non-injured persons, with potential future implementation for screening of re-injury anxiety. Twenty-three participants stood blindfolded on a translational balance perturbation platform. Consecutive auditory stimuli were provided as low (neutral stimulus [CS^–]) or high (conditioned stimulus [CS⁺]) tones. For the main experimental protocol (Protocol I), half of the high tones were followed by a perturbation in one of eight unpredictable directions. A separate validation protocol (Protocol II) requiring voluntary squatting without perturbations was performed with 12 participants. Event-related potentials (ERP) were computed from electroencephalography recordings and significant time-domain components were detected using an interval-wise testing procedure. High-amplitude early contingent negative variation (CNV) waves were significantly greater for CS⁺ compared with CS– trials in all channels for Protocol I (> 521-800ms), most prominently over frontal and central midline locations (P ≤ 0.001). For Protocol II, shorter frontal ERP components were observed (541-609ms). Our test paradigm revealed electrocortical activation possibly associated with movement-related fear. Exploring the discriminative validity of the paradigm among individuals with and without self-reported re-injury anxiety is warranted.

There is a lack of measures that quantify functional knee stability, which is of particular relevance in knee rehabilitation. Therefore, the aim of this study was to investigate the usefulness of knee finite helical axis (FHA) variables in 33 healthy subjects during two different functional tasks; One leg side hop (SH) and Two Leg Squat (TLS), and to investigate correlations of these variables with laxity. Laxity was assessed with a KT-1000 arthrometer and the Beighton Hypermobility Score. Movements were registered with an optical motion capture system. Knee rotation and translation were defined by a six degree of freedom segment model. FHA was calculated for finite steps of 20 degrees knee flexion, based on error simulations. We computed the FHA inclination, the translation along FHA and an FHA Direction Index quantifying directional changes. All variables were repeatable (average ICCs similar to 0.97 during TLS and similar to 0.83 during SH). The lower functional knee stability in SH was reflected by a significantly higher FHA Direction Index and a larger medio-lateral FHA inclination compared to those in TLS. The superior-inferior inclination was smaller during Landing in SH compared to Take-Off and TLS. Translation along FHA was generally small as expected in healthy subjects. Beighton Hypermobility Score and KT-1000 values had weak but significant correlations with FHA Direction Index and FHA translation, which show that laxity influences the functional knee stability. We conclude that FHA measures were sensitive enough to discriminate between SH and TLS. The next step is to investigate the usability of these measures in subjects with knee injury.

Introduction: An increased knowledge of how the brain control finger movements give us keys to understand the recovery of motor function after a brain injury. This knowledge is crucial for the development of reliable and valid assessment methods in the clinical evaluation of hand function.

Research question: How are individual finger movements represented in the brain? Investigating the associations between kinematics and brain activity responses in healthy individuals.

Methods: Keeping the others still. Finger movements were performed lying in the MR scanner in order to register brain activity response during the task. Optoelectronic cameras simultaneously monitored the positions of reflective markers affixed to each finger. The marker position data were used to calculate each finger's movement frequency (MF),  movement independence (“Individuation Index”, II), stationary ability (Stationarity Index, SI)[1][1]. fMRI data was analyzed by contrasting the finger movements against its active rest.

Results: Preliminary analyses showed that (1) the finger movements primarily activate sensorimotor areas in the contralateral hemisphere (Fig. 1A), (2) that use of kinematic parameters in the fMRI analyses improved spatial specificity and (3) II engage a number of cortical areas, while MF engage fewer areas (Fig. 1B–D). Further analyses will further explore activations maps for each individual finger.

Discussion: The inclusion of movement parameters in the fMRI analyses improves the specificity in the derived activation map, increasing the interpretability of the neural correlates of movement control. This advancement carries the promise for the development of better assessment methods of the recovery of function post-stroke with usability in rehabilitation practices.

A hip prosthesis design with larger femoral head size may improve functional outcomes compared to the conventional total hip arthroplasty (THA) design. Our aim was to compare the range of motion (RoM) in lower body joints during squats, gait and stair walking using a wearable movement analysis system based on inertial measurement units (IMUs) in three age-matched male groups: 6 males with a conventional THA (THAC), 9 with a large femoral head (LFH) design, and 8 hip- and knee-asymptomatic controls (CTRL). We hypothesized that the LFH design would allow a greater hip RoM, providing movement patterns more like CTRL, and a larger side difference in hip RoM in THAC when compared to LFH and controls. IMUs were attached to the pelvis, thighs and shanks during five trials of squats, gait, and stair ascending/descending performed at self-selected speed. THAC and LFH participants completed the Hip dysfunction and Osteoarthritis Outcome Score (HOOS). The results showed a larger hip RoM during squats in LFH compared to THAC. Side differences in LFH and THAC groups (operated vs. non-operated side) indicated that movement function was not fully recovered in either group, further corroborated by non-maximal mean HOOS scores (LFH: 83 +/- 13, THAC: 84 +/- 19 groups, vs. normal function 100). The IMU system may have the potential to enhance clinical movement evaluations as an adjunct to clinical scales.

Finite helical axis (FHA) measures of the knee joint during weight-bearing tasks may capture dynamic knee stability following Anterior Cruciate Ligament (ACL) injury. The aim was to investigate dynamic knee stability during two-leg squat (TLS) and one-leg side hop (SH) in a long-term follow-up of ACL injury, and to examine correlations with knee laxity (KT-1000), osteoarthritis (OA, Kellgren–Lawrence) and knee function (Lysholm score). Participants were injured 17–28 years ago and then treated with surgery (n=33, ACL_R) or physiotherapy only (n=37, ACL_PT) and healthy-knee controls (n=33) were tested. Movements were registered with an optical motion capture system. We computed three FHA inclination angles, its' Anterior–Posterior (A–P) position, and an index quantifying directional changes (DI), during stepwise knee flexion intervals of ∼15°. Injured knees were less stable compared to healthy controls' and to contralateral non-injured knees, regardless of treatment: the A–P intersection was more anterior (indicating a more anterior positioning of tibia relative to femur) positively correlating with high laxity/low knee function, and during SH, the FHA was more inclined relative to the flexion–extension axis, possibly due to reduced rotational stability. During the TLS, A–P intersection was more anterior in the non-injured knee than the injured, and DI was higher, probably related to higher load on the non-injured knee. ACL_R had less anterior A–P intersection than ACL_PT, suggesting that surgery enhanced stability, although rotational stability may remain reduced. More anterior A–P intersection and greater inclination between the FHA and the knee flexion–extension axis best revealed reduced dynamic stability ∼23 years post-injury.

Finite helical axis (FHA) measures of the knee joint during weight-bearing tasks may capture dynamic knee stability following Anterior Cruciate Ligament (ACL) injury. The aim was to investigate dynamic knee stability during two-leg squat (TLS) and one-leg side hop (SH) in a long-term follow-up of ACL injury, and to examine correlations with knee laxity (KT-1000), osteoarthritis (OA, Kellgren-Lawrence) and knee function (Lysholm score). Participants were injured 17-28 years ago and then treated with surgery (n=33, ACL(R)) or physiotherapy only (n=37, ACL(PT)) and healthy-knee controls (n=33) were tested. Movements were registered with an optical motion capture system. We computed three FHA inclination angles, its' Anterior-Posterior (A-P) position, and an index quantifying directional changes (DI), during stepwise knee flexion intervals of similar to 15 degrees. Injured knees were less stable compared to healthy controls' and to contralateral non-injured knees, regardless of treatment: the A-P intersection was more anterior (indicating a more anterior positioning of tibia relative to femur) positively correlating with high laxity/low knee function, and during SH, the FHA was more inclined relative to the flexion-extension axis, possibly due to reduced rotational stability. During the TLS, A-P intersection was more anterior in the non-injured knee than the injured, and DI was higher, probably related to higher load on the non-injured knee. ACL(R) had less anterior A-P intersection than ACL(PT), suggesting that surgery enhanced stability, although rotational stability may remain reduced. More anterior A-P intersection and greater inclination between the FHA and the knee flexion-extension axis best revealed reduced dynamic stability similar to 23 years post-injury.