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Abstract To uncover molecular changes underlying blood-brain-barrier dysfunction in Alzheimer’s disease, we performed single nucleus RNA sequencing in 24 Alzheimer’s disease and control brains and focused on vascular and astrocyte clusters as main cell types of blood-brain-barrier gliovascular-unit. The majority of the vascular transcriptional changes were in pericytes. Of the vascular molecular targets predicted to interact with astrocytic ligands, SMAD3, upregulated in Alzheimer’s disease pericytes, has the highest number of ligands including VEGFA, downregulated in Alzheimer’s disease astrocytes. We validated these findings with external datasets comprising 4,730 pericyte and 150,664 astrocyte nuclei. Blood SMAD3 levels are associated with Alzheimer’s disease-related neuroimaging outcomes. We determined inverse relationships between pericytic SMAD3 and astrocytic VEGFA in human iPSC and zebrafish models. Here, we detect vast transcriptome changes in Alzheimer’s disease at the gliovascular-unit, prioritize perturbed pericytic SMAD3-astrocytic VEGFA interactions, and validate these in cross-species models to provide a molecular mechanism of blood-brain-barrier disintegrity in Alzheimer’s disease.

Background: Monitoring the vital signs of delirious patients in an intensive care unit (ICU) is challenging, as they might (un-)intentionally remove devices attached to their bodies. In mock-up scenarios, we systematically assessed whether a motion detector (MD) attached to the bed may help in identifying emergencies. Methods: We recruited 15 employees of the ICU and equipped an ICU bed with an MD (IRON Software GmbH, Grünwald, Germany). Participants were asked to replay 22 mock-up scenes of one-minute duration each: 12 scenes with movements and 10 without movements, of which 5 were emergency scenes (“lying dead-still, with no or very shallow breathing”). Blinded recordings were presented to an evaluation panel consisting of an experienced ICU nurse and a physician, who was asked to assess and rate the presence of motions. Results: Fifteen participants (nine women; 173 ± 7.0 cm; 78 ± 19 kg) joined the study. In total, 286 out of 330 scenes (86.7%) were rated correctly. Ratings were false negative (FN: “no movements detected, but recorded”) in 7 out of 180 motion scenes (3.9%). Ratings were false positive (FP: “movements detected, but not recorded”) in 37 out of 150 scenes (24.7%), more often in men than women (26 out of 60 vs. 11 out of 90, respectively; p < 0.001). Of note, in 16 of these 37 FP-rated scenes, a vibrating mobile phone was identified as a potential confounder. The emergency scenes were correctly rated in 64 of the 75 runs (85.3%); 10 of the 11 FP-rated scenes occurred in male subjects. Conclusions: The MD allowed for identifying motions of test subjects with high sensitivity (96%) and acceptable specificity (75%). Accuracy might increase further if activities are recorded continuously under real-world conditions.

Purpose. To examine the effects of anemia on inpatient rehabilitation outcomes following unilateral and bilateral total knee arthroplasty (TKA). Method. This was a multicenter, retrospective study from 15 inpatient rehabilitation facilities. Patients ( N = 5421) with very low hematocrit (Hct <30%), low Hct (30-36% women, 30-41% men), or normal Hct (>36% women, 41% men) were included. Inpatient rehabilitation occurred following TKA. Functional independence measure (FIM) scores, length of stay (LOS), itemized hospital charges, discharge destination were main outcomes. Results. LOS was 13% longer and hospital charges were 12.5-18.0% higher in the very low Hct than remaining groups ( p = 0.0001). The FIM score and subscores for walking, stair climbing, bathing, transfers, and dressing changes were comparable for all Hct groups for the overall score. Hct <30% did not correspond to worse outcomes in patients with bilateral surgeries compared with unilateral surgeries; total FIM scores improved 47-53% across all Hct groups, regardless of bilateral surgical status. Discharge to home ranged 92.6-94.7% across all Hct groups ( p > 0.05). Conclusions. Rehabilitation teams can expect comparable functional improvements and discharge to home in anemic and non-anemic patients with either unilateral or bilateral surgeries without hematologic correction in the rehabilitation setting, but might need an additional day to accomplish these outcomes. [ABSTRACT FROM AUTHOR]

STUDY DESIGN: Randomized, controlled trial. OBJECTIVES: To assess the believability of a novel sham intervention for a neurodynamic technique (NDT) in participants with signs and symptoms of carpal tunnel syndrome (CTS). Additionally, we wished to assess a potential mechanism of NDT (hypoalgesia) and to compare outcomes related to clinical pain and upper extremity disability between NDT and a sham intervention. BACKGROUND: Preliminary evidence suggests that NDT is effective in the treatment of CTS. A sham-controlled study is lacking from the literature and could provide insight to the efficacy of NDT, as well as the corresponding mechanisms. METHODS: Participants with signs and symptoms consistent with CTS provided baseline measures of expectation, clinical pain intensity, upper extremity disability, and experimental pain sensitivity. Participants were then randomly assigned to receive either a NDT known to anatomicallystress the median nerve or a sham technique intended to minimize stress to the median nerve. Following brief exposure to the assigned technique, expectation was reassessed to observe for group-dependent changes. Participants received the assigned intervention over 3 weeks. Additionally, all participants received a prefabricated wrist splint for their involved hands, with instructions to sleep in the splint and to wear it during painful activities when awake. Following 3 weeks of the assigned intervention and splint wear, baseline measures were reassessed and participants were asked which intervention they believed they had received. RESULTS: Forty females agreed to participate. Expectations for pain relief and perceived group assignment were similar between the groups. Within-session decreases in clinical pain intensity and pressure pain sensitivity were observed independent of group assignment. Reduction of temporal summation was observed only in participants receiving NDT. Significant improvements in clinical pain intensity and upper extremity disability were observed at 3 weeks, independent of group assignment. CONCLUSION: The sham intervention was successful in blinding the participants. Immediate changes in pain sensitivity and intensity and 3-week changes in clinical pain intensity and upper extremity disability associated with NDT were equivalent to a sham intervention to which the participants were adequately blinded. Conversely, reduction of temporal summation was only observed in participants receiving the NDT, suggesting the potential of a favorable neurophysiological effect. LEVEL OF EVIDENCE: Therapy, level 1b. J Orthop Sports Phys Ther 2009;39(10):709-723. doi:10.2519/jospt.2009.3117. [ABSTRACT FROM AUTHOR]

OBJECTIVE: The Centers for Medicare and Medicaid Services (CMS) use a diagnostic category (revised in 2004) as one of eight criteria to determine whether a hospital is eligible for payment as an inpatient rehabilitation facility (IRF). Among the 13 specific categories of patients, there are three particular ones involving total knee arthroplasty (TKA) and hip arthroplasty (THA) patients. The purpose of this investigation was to analyze inpatient rehabilitation outcomes in TKA and THA patients, using these CMS criteria. DESIGN: A multicenter, retrospective study using a consecutive patient sample from 15 independent inpatient rehabilitation facilities, conducted from January 1, 2002 through March 31, 2006. All patients had either primary or revision TKA or THA and were directly admitted for inpatient rehabilitation postacute care. Patients were 23,274 men and women, separated into three comparison pairs on the basis of CMS eligibility criteria: (1) unilateral or bilateral arthroplasty, (2) age <85 yrs or >or=85 yrs, or (3) body mass index (BMI) <50 or >or=50 kg/m2. All patients underwent a comprehensive rehabilitation program that included physical and occupational therapies for 3 hrs/day. Main outcomes were inpatient rehabilitation length of stay (LOS), functionality as assessed by the FIM instrument, FIM efficiency, hospital charges, and discharge disposition. RESULTS: FIM efficiency scores were 8-21% lower in bilateral arthroplasties and patients aged >or=85 yrs, respectively (P < 0.0001). LOS was an average of 33% longer in patients >or=85 yrs than among patients <85 yrs (3.4 days; P < 0.0001). Total charges were 12-30% higher for patients with BMI >or=50 kg/m and >85 yrs than their comparative groups (P < 0.001). Arthroplasty patients <85 yrs were discharged more often to home compared with those >or=85 yrs (P = 0.0001). Patients >or=85 yrs were more likely to be transferred to a skilled nursing facility (7.4%) or back to acute care (3.9%) than those <85 yrs. CONCLUSIONS: All arthroplasty patients demonstrated improved physical function after inpatient rehabilitation. Those aged >or=85 yrs demonstrated the lowest efficiency, the greatest cost, and were the least likely to return home. [ABSTRACT FROM AUTHOR]

OBJECTIVE: To examine the major clinical and economic outcomes of cardiopulmonary patients referred for inpatient rehabilitation or skilled nursing care after an acute care stay. DESIGN: Retrospective, exploratory study conducted at inpatient rehabilitation facilities (IRF) and a matched skilled nursing facility (SNF). Participants were cardiovascular and pulmonary patients (n = 495; 76.2 +/- 0.5 yrs). Measurements included changes in functionality (assessed by functional independence measure [FIM] and minimum data set [MDS]), length of stay (LOS), total and itemized facility charges, discharge disposition, and mortality. RESULTS: Participation in physical and occupational therapies occurred during 72-78% and 48-51% of total days in the IRF and SNF, respectively (P < 0.001). Changes in eating, grooming, bathing, dressing, toileting, bed-chair transfers, walking, verbal expression, problem solving, and auditory comprehension were greater in patients from the IRF than SNF (all P < 0.0001). LOS was longer in the SNF than IRF (34.7 +/- 3.4 vs. 14.9 +/- 0.5 days, P < 0.0001). In the IRF compared with the SNF, total charges ($22,162 vs. $10,873), pharmacy charges ($3104 vs. $1604), and combined physical and occupational therapy charges were higher ($5225 vs. $3582), all P < 0.0001. More IRF patients than SNF patients were discharged home (77.5% vs. 44.1%), and fewer IRF patients than SNF patients were discharged to acute care (15.8% vs. 23.2%) or expired (1.3% vs. 13.6%) during their stay (P < 0.05). CONCLUSIONS: More patients achieved functional independence, had shorter LOS, and had a higher rate of homebound discharge in the IRF than in the SNF, and this is associated with a higher cost of care. These SNF outcomes may be related to advancing age, type of illness, dementia, and inability to fully participate in therapies. [ABSTRACT FROM AUTHOR]

OBJECTIVES: To examine age and gender effects on outcomes after inpatient rehabilitation in primary total knee arthroplasty (TKA) and revision TKA patients. DESIGN: This retrospective, comparative study was conducted in a 50-bed, university-affiliated rehabilitation hospital. Patients included primary TKA patients (n = 286) and revision TKA patients (n = 138) placed into one of three age brackets: < 60 yrs, 60-70 yrs, or > 70 yrs. Measurements included length of stay (LOS), FIM scores, hospital charges, and discharge disposition location. RESULTS: FIM scores improved from admission to discharge in both primary and revision patients (P = 0.015). LOS was shorter in primary than revision patients (8.3 vs. 10.4 days, P = 0.001), and the LOS was longest in patients > 70 yrs compared with those < 60 or 60-70 yrs (10.6 vs. 8.7 and 8.8 days, respectively; P = 0.004). FIM efficiency was greater in primary than in revision TKA patients (3.68 vs. 2.77 points/day, P = 0.001), and greater for men than women in each age bracket regardless of TKA type (3.68 vs. 2.78 points/day, P = 0.001). Total hospital charges were lower for men than women for both TKA types ($9,656 +/- 823 vs. $11,544 +/- 1,359; P = 0.015), and were highest in patients > 70 yrs of age (P = 0.015). CONCLUSIONS: Primary and revision TKA patients make improvements in functional independence during inpatient rehabilitation. Although FIM gains were similar among age and gender groupings, FIM efficiency is lowest in women. Despite similar daily hospital costs among the groups, slower progress with functional gains (decreased FIM efficiency) increases the LOS and total hospital charges, especially in older women. [ABSTRACT FROM AUTHOR]

PURPOSE: This study compared lipid peroxidation values in nonobese and obese postmenopausal women before and after acute maximal aerobic exercise (AX). METHODS: Blood samples were collected in nonobese (22.1 +/- 0.9% body fat) and obese (40.8 +/- 0.9% body fat) women (61-75 yr, N = 34) before and immediately after a maximal graded treadmill test. Lipid hydroperoxides (PEROX), cholesterol, and thiol profiles were measured. Oxygen consumption (V(O2), respiratory exchange ratios (RER), and minute ventilation (VE) values were determined before and during exercise. RESULTS: PEROX levels were not different between the nonobese and obese groups at baseline (2.4 vs 2.8 nmol.mL(-1), respectively) or post-AX (2.8 vs 3.2 nmol.mL(-1), respectively) (P > 0.05). When expressed as DeltaPEROX (nmol.mL(-1))/DeltaVO(2) (mL.kg(-1).min(-1)), to account for different exercise durations, the obese group had a greater lipid peroxidation response compared with the nonobese group (0.13 vs 0.02 (nmol.mL(-1)).mL(-1).kg(-1).min(-1), respectively; P < 0.05). Regression analysis revealed that when baseline PEROX and body fat values were controlled, age, exercise intensity, and duration were significant contributors to the DeltaPEROX/DeltaV(O2) after AX (R(2) = 0.536 P < 0.05). CONCLUSION: For a given oxidative challenge (exercise-associated oxygen utilization), older, obese women were at a greater risk for oxidative stress compared with nonobese counterparts. [ABSTRACT FROM AUTHOR]

Although remote ischemic pre-conditioning (RIPC) reduced infarct size in animal experiments and proof-of-concept clinical trials, recent phase III trials failed to confirm cardioprotection during cardiac surgery. Here, we characterized the kinetic properties of humoral factors that are released after RIPC, as well as the signal transduction pathways that were responsible for cardioprotection in an ex vivo model of global ischemia reperfusion injury. Venous blood from 20 healthy volunteers was collected at baseline and 5 min, 30 min, 1 h, 6 h, and daily from 1 to 7 days after RIPC (3 × 5/5 min upper-limb ischemia/reperfusion). Plasma-dialysates (cut-off: 12 to 14 kDa; dilution: 1:20) were infused into Langendorff-perfused mouse hearts subjected to 20/120 min global ischemia/reperfusion. Infarct size and phosphorylation of signal transducer and activator of transcription (STAT)3, STAT5, extracellular-regulated kinase 1/2 and protein kinase B were determined. In a subgroup of plasma-dialysates, an inhibitor of STAT3 (Stattic) was used in mouse hearts. Perfusion with baseline-dialysate resulted in an infarct size of 39% of ventricular mass (interquartile range: 36% to 42%). Perfusion with dialysates obtained 5 min to 6 days after RIPC significantly reduced infarct size by ∼50% and increased STAT3 phosphorylation beyond that with baseline-dialysate. Inhibition of STAT3 abrogated these effects. These results suggest that RIPC induces the release of cardioprotective, dialyzable factor(s) within 5 min, and that circulate for up to 6 days. STAT3 is activated in murine myocardium by RIPC-induced human humoral factors and is causally involved in cardioprotection.

Friction behavior in a sliding contact is strongly influenced by the surface topography of the bodies in contact. This also applies to friction clutches. Even small differences in surface topography may cause significant differences in friction behavior. Thus, it is important to be able to characterize the micro-contact of the rough sliding surfaces, which are, in the case of a clutch, steel plate and friction material. One important measure for the characterization of the micro-contact is the real area of contact. Another important aspect is the contact pattern. The article introduces a method to implement a FEM (Finite Element Method) model from real surface measurements. Real surface topography of the friction pairing is considered. The simulation method is applied to different friction pairings and operating conditions. Computational results with rough and smooth steel plates, new and run-in friction linings, and different nominal surface pressure verify the model. In addition, the results on real area of contact between a steel and a friction plate are compared with published values.

Background: Unlike other sports, the relationship between performance deficits and pain/injury in lacrosse players has not been well-investigated., Purpose: The purposes of this study were to: 1) determine whether age and sex differences exist in dynamic physical function tests and drop jump performance among lacrosse players, and 2) determine whether pre-seasonal physical function scores predict onset of either lower extremity or low back pain over time., Study Design: Prospective observational study., Methods: Lacrosse players (N=128) were stratified into three groups: 12-14.9 yrs, 15-18 yrs and >18 yrs. Thomas test (hip flexibility), Ober's test (iliotibial band tightness), and Ely's test (rectus femoris tightness) were performed. Landing Error Scoring System (LESS) scores were collected while players performed drop jumps. Sagittal and frontal plane movement from 2D video during single and double legged squats was assessed. Musculoskeletal pain symptoms or injury were tracked for six months. Age bracket, sex and physical function scores were entered into logistic regression models to determine risk factors that predicted onset of lower extremity pain and low back pain onset., Results: LESS scores and single-leg squat movement quality test scores were lowest in the 12-14.9 yr groups and highest in the >18 yr group (all p<0.05). Single leg squat performance score increased the odds risk (OR) for lower extremity pain (OR=2.62 [95% CI 1.06-6.48], p=.038) and LESS scores elevated risk for low back pain onset over six months (OR = 2.09 [95% CI 1.07- 4.06], p= .031)., Conclusions: LESS scores and single legged squat performance may help identify lacrosse players at risk for musculoskeletal pain or injury onset. Detecting these pertinent biomechanical errors and subsequently developing proper training programs could help prevent lower extremity and low back pain onset., Level of Evidence: III., Competing Interests: None to declare., (© The Author(s).)

Background: Low back pain (LBP) is an understudied condition among runners, and it is unclear what biomechanical features could be targeted for gait retraining to mitigate pain., Research Question: How do running biomechanics differ between healthy individuals and those with running-related LBP?, Methods: This was a case-controlled, comparative study design of community runners: running-related LBP (n=52) and healthy controls (n=52). All runners completed running history forms and performed a 3-dimensional gait analysis. Kinematic data were collected using a motion capture system and normalized to a gait cycle, while participants ran on a level grade at self-selected speed on an instrumented treadmill. Current running volume, temporal-spatial, kinetic and kinematic features were compared between groups., Results: The LBP group had 39.5 % lower weekly distance and 15.4 % fewer were currently training for a race (all p<.05). Runners with LBP demonstrated lower cadence (166±10 step/min vs. 171±9 step/min; p=.05), greater center of gravity lateral displacement (1.4±0.5 cm vs. 1.2 ±.3 cm; p=.044) and greater stride width variability (1.3±0.4 cm versus 1.0 ± 0.04 cm; p=.008). Runners with LBP had a greater Vertical Average Loading Rate ([VALR] 67.7±22.2 bodyweights [BW]/s vs. 62.2±21.5 BW/s; p=.022), and higher joint moments (N*m/(kg*m)) at the knee in the sagittal plane (2.13±0.50 vs. 1.87±0.56; p <.001), frontal plane (1.44±0.39 vs. 1.29±0.29; p=.013), and at the hip in the frontal plane (2.04±0.51 vs. 1.84±0.41; p=.024). No differences were found between groups in the pelvis, hip, knee, and ankle joint excursions in any plane of motion during a typical gait cycle., Significance: These collective motion signature may reflect challenges with control of motion and VALR in the presence of back pain. Cadence training to increase step rate, coupled with core/hip muscle activation, may be an important strategy to reduce motion variability, impact loading rate and pain symptoms while running., Competing Interests: Declaration of Competing Interest The authors have nothing to disclose., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Background: The concordance between radiograph-derived Kellgren-Lawrence (KL) scores for knee osteoarthritis (KOA) and experimental and clinical pain and KOA-related physical function is conflicting., Objectives: We investigate whether the inclusion of dispositional traits reduces variability between KOA radiographic findings, experimental pain, clinical pain, and function in individuals with knee pain., Design: This study is a cross-sectional, secondary analysis of data collected from the UPLOAD-II study., Methods: Adults aged 45-85 years with and without knee pain were enrolled. Data collected included sociodemographics, knee radiographs, experimental pain, clinical pain and function, and trait affect. Vulnerable and protective dispositional traits were classified from combined positive and negative trait affect measures. KL scores were determined from the knee radiographs. Unadjusted and adjusted (age, sex, comorbidities, and body mass index) regression analyses were completed with SAS version 9.4 (Cary, NC, USA)., Results: The study included 218 individuals with a mean age of 58 years, 63.6% women, and 48.2% non-Hispanic black adults. Dispositional traits were associated with the experimental pain measures. No association between radiographic KOA and experimental pain was observed. In a combined and adjusted analysis, dispositional traits were predictive of knee punctate pain temporal summation ( p  = 0.0382). Both dispositional traits and radiographic KOA scores independently and combined were predictive of Graded Chronic Pain Scale pain and function, and Western Ontario and McMaster University pain and function ( p s ⩽ 0.01). Improvements in R 2 were noted across all models with the inclusion of dispositional traits., Conclusion: Consideration of dispositional traits reduces the variability between radiographic KOA and pain and function. Non-pathological and associated pain-related psychological factors and dispositional traits might serve as parsimonious proxy tools to improve clinical assessments., Registration: N/A., Competing Interests: The authors declare that there is no conflict of interest., (© The Author(s), 2024.)

Body weight significantly impacts health and quality of life, and is a leading risk factor for the development of knee osteoarthritis (OA). Weight cycling may have more negative health consequences compared to steady high or low weight. Using the Osteoarthritis Initiative dataset, we investigated the effects of weight cycling on physical function, quality of life, and depression over 72-months compared to stable or unidirectional body weight trajectories. Participants (n = 731) had knee OA and were classified as: (1) stable-low (BMI < 25), (2) stable-overweight (BMI = 25-29.9), and (3) stable-obese (BMI ≥ 30); (4) steady-weight-loss; (5) steady-weight-gain (weight loss/gain ≥ 2.2 kg every 2-years); (6) gain-loss-gain weight cycling, and (7) loss-gain-loss weight cycling (weight loss/gain with return to baseline), based on bi-annual assessments. We compared Knee Injury and Osteoarthritis Outcome Knee-Related Quality of Life, Function in Sports and Recreation, Physical Activity in the Elderly, Short Form SF-12, repeated chair rise, 20-m gait speed, and Center for Epidemiological Studies Depression using repeated-measures ANOVA. The steady weight loss group demonstrated the worst pain, physical function, and depressive symptoms over time (p's < 0.05). More research is needed to confirm these findings, and elucidate the mechanisms by which steady weight loss is associated with functional decline in knee OA., (© 2023. Springer Nature Limited.)

Purpose: Muscle contraction type in resistance exercise training may confer benefits besides strength in individuals with osteoarthritis and cardiovascular disease (CVD) risks. The purpose of the study was to explore whether Eccentric-resistance training (RT) improved hemodynamic responses to acute walking exercise stress compared to Concentric-RT among individuals with knee OA over four months., Methods: This was a secondary analysis from a randomized, controlled, single-blinded study. Participants (N = 88; 68.3 ± 6.4 yrs; 67.4% female) were randomized to one of two work-matched resistance training (RT) programs against a non-RT control group. Pre-training and month four, participants completed a self-paced Six-Minute Walk Test (6MWT) and progressive treadmill exercise test. Heart rates, blood pressures and mean arterial pressures (MAP) were captured during each test. Antihypertensive medications use was documented at each time point., Results: Leg strength improved in both training groups by month four (p < .05). Changes in 6MWT distance and progressive treadmill test time were not different across groups over four months. Neither Concentric or Eccentric RT produced different hemodyamic responses during the 6MWT compared to the control group post-training. However, Concentric RT was associated with 6.0%-7.4% reductions in systolic blood pressure during the graded treadmill walking test at 50%, 75% and 100% of the test time compared to Eccentric RT and the controls (p = .045). MAP values were lower at 75% and 100% of the treadmill test after Concentric RT (5.7%-6.0% reductions) compared to Eccentric RT (1.0%-2.4% reductions) and controls (1.5% and 4.0% elevations) post-training (p = .024). Antihypertensive medication use did not change in any group., Conclusions: The repeated, progressive exposures of Concentric RT-induced blunted the hypertensive responses to acute exercise compared to Eccentric-RT. Among people with knee OA, Concentric-RT may confer strength benefits to manage OA and possibly reduce cardiovascular stress during exercise., (© 2023. The Author(s).)

After an anterior cruciate ligament (ACL) injury, people need secondary prevention strategies to identify osteoarthritis at its earliest stages so that interventions can be implemented to halt or slow the progression toward its long-term burden. The Osteoarthritis Action Alliance formed an interdisciplinary Secondary Prevention Task Group to develop a consensus on recommendations to provide clinicians with secondary prevention strategies that are intended to reduce the risk of osteoarthritis after a person has an ACL injury. The group achieved consensus on 15 out of 16 recommendations that address patient education, exercise and rehabilitation, psychological skills training, graded-exposure therapy, cognitive-behavioral counseling (lacked consensus), outcomes to monitor, secondary injury prevention, system-level social support, leveraging technology, and coordinated care models. We hope this statement raises awareness among clinicians and researchers on the importance of taking steps to mitigate the risk of osteoarthritis after an ACL injury., (© by the National Athletic Trainers' Association, Inc.)

Context: The Osteoarthritis Action Alliance formed a secondary prevention task group to develop a consensus on secondary prevention recommendations to reduce the risk of osteoarthritis after a knee injury., Objective: Our goal was to provide clinicians with secondary prevention recommendations that are intended to reduce the risk of osteoarthritis after a person has sustained an anterior cruciate ligament injury. Specifically, this manuscript describes our methods, literature reviews, and dissenting opinions to elaborate on the rationale for our recommendations and to identify critical gaps., Design: Consensus process., Setting: Virtual video conference calls and online voting., Patients or Other Participants: The Secondary Prevention Task Group consisted of 29 members from various clinical backgrounds., Main Outcome Measure(s): The group initially convened online in August 2020 to discuss the target population, goals, and key topics. After a second call, the task group divided into 9 subgroups to draft the recommendations and supportive text for crucial content areas. Twenty-one members completed 2 rounds of voting and revising the recommendations and supportive text between February and April 2021. A virtual meeting was held to review the wording of the recommendations and obtain final votes. We defined consensus as >80% of voting members supporting a proposed recommendation., Results: The group achieved consensus on 15 of 16 recommendations. The recommendations address patient education, exercise and rehabilitation, psychological skills training, graded-exposure therapy, cognitive-behavioral counseling (lacked consensus), outcomes to monitor, secondary injury prevention, system-level social support, leveraging technology, and coordinated care models., Conclusions: This consensus statement reflects information synthesized from an interdisciplinary group of experts based on the best available evidence from the literature or personal experience. We hope this document raises awareness among clinicians and researchers to take steps to mitigate the risk of osteoarthritis after an anterior cruciate ligament injury., (© by the National Athletic Trainers' Association, Inc.)

Abstract: Healthy running form is characterized by motion that minimizes mechanical musculoskeletal injury risks and improves coactivation of muscles that can buffer impact loading and reduce stresses related to chronic musculoskeletal pain. The American College of Sports Medicine Consumer Outreach Committee recently launched an infographic that describes several healthy habits for the general distance runner. This review provides the supporting evidence, expected acute motion changes with use, and practical considerations for clinical use in patient cases. Healthy habits include: taking short, quick, and soft steps; abdominal bracing; elevating cadence; linearizing arm swing; controlling forward trunk lean, and; avoiding running through fatigue. Introduction of these habits can be done sequentially one at a time to build on form, or more than one over time. Adoption can be supported by various feedback forms and cueing. These habits are most successful against injury when coupled with regular dynamic strengthening of the kinetic chain, adequate recovery with training, and appropriate shoe wear., (Copyright © 2022 by the American College of Sports Medicine.)

This prospective cohort study examined the impact of high anxiety levels on psychological state and gait performance during recovery in runners with lower body injuries. Recreational runners diagnosed with lower body injuries who had reduced running volume (N = 41) were stratified into groups using State Trait Anxiety Inventory (STAI) scores: high anxiety (H-Anx; STAI ≥40 points) and low anxiety (L-Anx; STAI <40 points). Runners were followed through rehabilitation to return-to-run using monthly surveys. Main outcome measures included kinesiophobia (Tampa Scale of Kinesiophobia, TSK-11), Positive and Negative Affect Schedule (PANAS; Positive and negative scores), Lower Extremity Function Scale (LEFS), running recovery (University of Wisconsin Running Injury and Recovery Index [UWRI]) and CDC Healthy Days modules for general health, days of anxiety/tension, disrupted sleep and work/usual activities. Running biomechanics were assessed at baseline and the final visit using 3D motion capture and a force-plated treadmill. The time to return-to-running for was 5.0±3.1 and 7.9±4.1 months for L-Anx and H-Anx, respectively and participants who withdrew (n = 15) did so at 7.7±6.2 months. L-Anx maintained low anxiety and H-Anx reduced anxiety from baseline to final visit (STAI = 31.5 to 28.4 points, 50.4 to 37.8 points, respectively), whereas the withdrawn runners remained clinically anxious at their final survey (41.5 to 40.3 points; p < .05). Group by time interactions were found for PANAS positive, LEFS UWRI, general health scores, and days feeling worry, tension and anxiety (all p < .05). Final running performance in L-Anx compared to H-Anx was most improved with cadence (8.6% vs 3.5%; p = .044), impact loading rate [-1.9% vs +8.9%] and lower body stiffness [+14.1% vs +3.2%; all p < .05). High anxiety may identify runners who will experience a longer recovery process, health-related functional disruptions, and less optimization of gait biomechanics during rehabilitation after a lower extremity injury., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2022 Madsen et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Anti-gravity treadmill training is a therapeutic option to help recovering runners return to activity after injury. This current concept paper provides a synopsis of the latest evidence of the biomechanical and metabolic changes that occur with body weight support (BWS) treadmill training, effects of antigravity treadmill training on clinical outcomes and clinical case studies in injured runners. Literature searches identified studies with descriptive, experimental and interventional designs and case studies that examined acute and chronic use of antigravity treadmills in runners and relevant populations. Laboratory-based studies were included to provide technical considerations for rehabilitation programming. Antigravity treadmills use causes reductions in cadence, ground reaction forces (GRF), GRF impulses, knee and ankle range of motion, and vertical stiffness, with elevations in stride duration, flight time, ground contact time, and plantarflexion. Antigravity treadmills appear useful across a spectrum of injuries in runners, including postsurgical repair of osteochondral defect, stress reactions (medial tibia, pelvis), and lumbar disc herniation. Runners may preserve aerobic fitness, muscle activation patterns, and muscle mass during recovery compared to traditional rehabilitation protocols. Technical considerations for accurate loading include treadmill frame adjustment to appropriate height to ensure accuracy of level of BWS while running, and monitoring for fast cadence to ensure impact loading rates remain low. Speed or grade can be increased to maintain metabolic demand and fitness while minimizing bone and tissue loading. Monitoring for symptom provocation will guide protocol adjustments to BWS and prescriptions. Once able to run pain-free (sustained or interval) >95% BWS for >30 min, the runner is likely ready to safely transition to ground running. Antigravity treadmill training can be considered when available to facilitate smooth transition back to ground running in a conditioned state., (© 2021 The Authors.)

This current concept, narrative review provides the latest integrated evidence of the musculoskeletal injuries involved with trail running and therapeutic strategies to prevent injury and promote safe participation. Running activities that comprise any form of off-road running (trail running, orienteering, short-long distance, different terrain, and climate) are relevant to this review. Literature searches were conducted to 1) identify types and mechanisms of acute and chronic/overuse musculoskeletal injuries in trail runners, 2) injury prevention techniques most relevant to running trails, 3) safe methods of participation and rehabilitation timelines in the sport. The majority of acute and chronic trail running-related musculoskeletal injuries in trail running occur in the lower leg, primarily in the knee and ankle. More than 70% are due to overuse, and ankle sprains are the most common acute injury. Key mechanisms underlying injury and injury progression include inadequate neuromotor control-balance-coordination, running through fatigue, and abnormal kinematics on variable terrain. Complete kinetic chain prehabilitation programs consisting of dynamic flexibility, neuromotor strength and balance, and plyometrics exercise can foster stable, controlled movement on trails. Patient education about early musculoskeletal pain symptoms and training adjustment can help prevent injury from progressing to serious overuse injuries. Real-time adjustments to cadence, step length, and knee flexion on the trail may also mitigate impact-related risk for injury. After injury occurs, rehabilitation will involve similar exercise components, but it will also incorporate rest and active rest based on the type of injury. Multicomponent prehabilitation can help prevent musculoskeletal injuries in trail runners through movement control and fatigue resistance., (© 2021 The Authors.)

This study determined the prevalence of joint pain among lacrosse officials and described the impact of pain thereof on current officiating duties on the field. Members of the US Lacrosse Officials Development Programme were provided with an electronic survey (a 15.7% response rate resulted in N = 1,441 of completed surveys). Pain sites and severity, previous injuries and current impact of musculoskeletal pain on officiating duties were captured. Pain was present in 18.1-40.1% of respondents at the foot, shoulder, back and knee. A total of 437 officials reported diagnoses of osteoarthritis ([OA]; knee 48.7%, hip 10.5%, spine 10.1%, shoulder 8.0%) and 247 reported OA in more than one joint (p < .05). Officials with OA or previous lacrosse-related injuries reported frequent difficulty with running the entire field distance (p < 0.0001), starting and stopping on the field (p < 0.0001), keeping pace (p < 0.0001), focusing on multiple actions of players at once (p < 0.0001), and enjoyment (all p < 0.0001). Musculoskeletal pain is a common, unrecognized issue in this population that interferes with sport officiating functions. Additional study is needed to objectively determine the impact of OA pain and musculoskeletal injuries on measurable performance outcomes on the field and subjective measures of focus, attention and enjoyment.

Purpose: Approximately 185 000 individuals undergo limb amputations every year. Of this population, 40% experience lower extremity amputations. A common musculoskeletal condition that develops after amputation is chronic low back pain (LBP). LBP may be a consequence of one or combined mechanical factors including muscle atrophy, strength loss, level of amputation, kinematic traits of movement, mechanical loading and forces, prosthetic design/use and leg length discrepancy. Secondary consequences of LBP may collectively include the dependence of pain medications, impaired physical function, and diminished quality of life (QOL). Methods: A systematic literature search using PubMed was conducted to identify articles of low back pain in lower limb amputees. Results: Long-term interventions are needed to reduce the incidence, prevalence, and secondary impacts of LBP in amputees. Resistance exercise has strong potential to help correct mechanical deficits in lower limb amputees. Resistance exercise adaptations that can be beneficial for this population include improved neuromuscular control, increases in lumbar and core muscle strength cross-sectional area, and improved gait motion parameters. Conclusions: This narrative review provides an overview of the key mechanical and physiological factors which may contribute to chronic LBP in amputees, and discusses the use of resistance exercise training to combat these mechanical factors to improve pain symptoms.IMPLICATIONS FOR REHABILITATIONLow back pain is more prevalent in the amputee population compared to the general population.Low back pain may be due several mechanical factors that develop after a unilateral amputation.Lower extremity amputees with chronic low back pain experience compounded physical activity avoidance and functional limitations.Chronic low back pain in amputees erodes quality of life more than people with back pain or amputation alone.Therapeutic interventions, such as core strengthening and stabilization exercises, have strong potential to provide low back pain relief for amputees.

Background: Some recreational runners with obesity successfully train or compete without musculoskeletal injury. Insight into the key kinetic strategies of injury-free heavier runners is necessary to appropriately guide development of safe training programs for this population., Objective: To determine key biomechanical strategies of running in individuals with body mass index (BMI) values above and equal to and higher than 30 kg/m 2 ., Design: This was a case-control study., Participants: Runners with obesity (n =18; 42.7 years, 38.9% women) who were matched by sex, age, footstrike type, footwear characteristics, and running speed with healthy runners (n = 36; 41.7 years, 32.5% women)., Setting: Research laboratory affiliated with an academic medical center., Methods: A seven-camera optical motion analysis system was used to capture running kinematics and an instrumented treadmill captured kinetic data., Main Outcomes: Main outcomes were temporal spatial parameters, joint excursions, peak ground reaction forces (GRFs), joint moments, vertical average loading rate (VALR), impulses, and vertical stiffness (K vert )., Results: Runners with obesity demonstrated 15% less vertical excursion of the center of mass, 18% wider strides, and 3% longer stance times than nonobese runners (P < .05). Normalized peak GRFs and VALRs were higher in the nonobese group. GRF impulse was higher in the group with obesity compared to the nonobese group (means ± SD; 339.6 ± 55.2 Ns vs. 255.0 ± 45.8 Ns; P = .0001). K vert was higher in the obese group compared to the nonobese group (238.6 ± 50.3 N/cm vs. 183.1 ± 29.4 N/cm; P = .0001). Peak hip moments were higher in runners with obesity in the sagittal and frontal planes (P < .05)., Conclusion: Runners with obesity dampened impact forces and controlled loading rate more than nonobese runners by increasing lower body stiffness and constraining vertical displacement., (© 2020 American Academy of Physical Medicine and Rehabilitation.)

Objective: The aim of the study was to compare the effectiveness of concentrically focused resistance training to eccentrically focused resistance training on physical function and functional pain in knee osteoarthritis., Design: This is a randomized, single-blinded controlled 4-mo trial. Older adults with knee osteoarthritis (N = 88; 68.3 ± 6.4 yrs, 30.4 ± 6.9 kg/m, and 67.4% women) were randomized to eccentrically focused resistance training, concentrically focused resistance training, or no-exercise control. Main outcomes included chair rise time, stair climb time, 6-min walk test distance, temporal-spatial parameters of gait, community ambulation, and functional pain., Results: Leg muscle strength improved in both training groups compared with no-exercise control. There were no significant group × time interactions for any functional performance score (chair rise time, stair climb time, 6-min walk test distance, gait parameters, community ambulation). Compared with no-exercise control, functional pain scores were reduced for chair rise (-38.6% concentrically focused resistance training, -50.3% eccentrically focused resistance training vs. +10.0%) and stair climb (-51.6% concentrically focused resistance training, -41.3% eccentrically focused resistance training vs. +80.7%; all P < 0.05). Pain scores were reduced during the 6-min walk and in early recovery with concentrically focused resistance training compared with the remaining two groups (P < 0.05)., Conclusions: Either resistance exercise type improves activity-related knee osteoarthritis pain, but concentrically focused resistance training more effectively reduced severity of ambulatory pain and pain upon walking cessation.

Introduction: This study aimed to compare the efficacy of eccentrically focused resistance exercise (ECC RT) to concentrically focused resistance exercise (CNC RT) on knee osteoarthritis (OA) symptoms and strength., Methods: Ninety participants consented. Participants were randomized to CNC RT, ECC RT, or a wait-list, no-exercise control group. Four months of supervised exercise training was completed using traditional weight machines (CNC RT) or modified-matched machines that overloaded the eccentric action (ECC RT). Main outcomes included one-repetition maximal strength (knee extension, leg flexion, and leg press), weekly rate of strength gain, Western Ontario and McMaster University Osteoarthritis Index (WOMAC) total score and subscores., Results: Fifty-four participants (60-85 yr, 61% women) completed the study. Both CNC RT and ECC RT groups showed 16%-28% improvement relative to the wait-list, no-exercise control group (P = 0.003-0.005) for all leg strength measures. The rate of weekly strength gain was greater for CNC RT than for ECC RT for leg press and knee flexion (by 2.9%-4.8%; both, P < 0.05) but not knee extension (0.7%; P = 0.38). There were no significant differences in WOMAC total and subscores across groups over time. Leg press strength change was the greatest contributor to change in WOMAC total scores (R = 0.223). The change in knee flexion strength from baseline to month 4 was a significant predictor of the change in WOMAC pain subscore (F ratio = 4.84, df = 45, P = 0.032). Both modes of strength training were well tolerated., Conclusions: Both resistance training types effectively increased leg strength. Knee flexion and knee extension muscle strength can modify function and pain symptoms irrespective of muscle contraction type. Which mode to pick could be determined by preference, goals, tolerance to the contraction type, and equipment availability.

The ulnar collateral ligament (UCL) of the elbow has been a subject of extensive research and discussion in recent years not only in the medical community but also in the media and by coaches, players, and parents. This is in part due to the rising incidence of UCL injuries and subsequent surgical reconstruction, specifically in overhead throwing athletes. Due to this widespread increase in injury to this structure, it is paramount to understand when it is appropriate to pursue nonoperative versus operative management. As such, the purpose of this article will be to review the basic anatomy, risk factors for UCL injury in overhead throwing athletes, treatment approaches, and future directions for prevention and treatment of injury based on the evidence-based data in the peer-reviewed literature.

Background: Distance runners can approach long descents with slow cadence and long steps, or a fast cadence with shorter steps. These approaches differentially affect mechanical loading and energy demand., Research Question: This study determined the cadence range in which biomechanical loads, caloric unit cost and energy cost were simultaneously minimized during downhill running (DR)., Methods: Trained runners (N = 40; 25.6 ± 7.2 yr; 42.5% female) participated in this experimental study. Participants ran on an instrumented treadmill while wearing a portable gas analyzer during six conditions: control normal level running (LR) at 0 deg inclination (CON-0); control DR -6 deg inclinaton (CON-6); DR at cadences +/-5% and +/-10% different from CON-6. A motion analysis system was used to capture running motion, and an instrumented treadmill captured force data. Cardiopulmonary measures, rating of perceived exertion (RPE), and biomechanical measures (temporal spatial parameters, peak ground reaction forces [GRF], vertical average loading rate [VALR], impulses) were calculated. Caloric unit cost and energy costs were standardized per unit distance., Results: Running at -10% cadence increased HR by 10 bpm compared to CON-6 (p < 0.0001). Vertical excursion of the center of mass and step length were greatest in the cadence -10% and least in the cadence +10% conditions (both p < 0.0001). RPEs were higher among all cadence conditions compared to CON-0 (p < 0.0001). Caloric unit costs were lowest in CON-6, and +/5% cadence conditions compared to the CON-0 and +/-10% conditions (-2.1% to -12.3%, respectively; p < 0.05). Peak GRF and VALR were not different among conditions; vertical impulses were greatest in the -10% condition compared to CON-0, CON-6 and +5% and +10% by 11.3-14.5% (p < .001)., Significance: Changing cadence across level and downhill stretches is likely not necessary and may actually increase perceived effort of running. Running downhill at cadences that range +/-5% of preferred simultaneously minimize caloric unit cost and impulse loading., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Lacrosse imposes multiple simultaneous physical demands during play including throwing and catching a ball while holding a crosse, running, cutting, and jumping. Often, these skills are completed while experiencing contact from another player leading to both on-and-off platform movements. Other motions include defensive blocking and pushing past defenders. Repetitive motions over sustained durations in practice or competition impart mechanical stresses to the shoulder or elbow joints, supportive muscles, and connective tissue. Preparation for lacrosse participation involves bilateral optimization of strength and durability of stabilizer muscles. Passing and shooting skills are encouraged to be equally effective on both sides; therefore, symmetric strength and flexibility are vital for prehabilitation and rehabilitation efforts. This article will: 1) provide insights on the upper-extremity musculoskeletal demands of lacrosse and related sports with similar throwing motion and 2) describe prehabilitation and rehabilitation methods that improve athlete durability and reduce likelihood of upper-extremity injury.

In a pilot randomized clinical trial, participants aged ≥60 years ( n = 35) with physical limitations and symptomatic knee osteoarthritis (OA) were randomized to 12 weeks of lower-body low-load resistance training with blood-flow restriction (BFR) or moderate-intensity resistance training (MIRT) to evaluate changes in muscle strength, pain, and physical function. Four exercises were performed three times per week to volitional fatigue using 20% and 60% of one repetition maximum (1RM). Study outcomes included knee extensor strength, gait speed, Short Physical Performance Battery (SPPB) performance, and pain via the Western Ontario and McMaster Universities OA Index (WOMAC). Per established guidance for pilot studies, primary analyses for the trial focused on safety, feasibility, and effect sizes/95% confidence intervals of dependent outcomes to inform a fully-powered trial. Across three speeds of movement, the pre- to post-training change in maximal isokinetic peak torque was 9.96 (5.76, 14.16) Nm while the mean difference between groups (BFR relative to MIRT) was -1.87 (-10.96, 7.23) Nm. Most other directionally favored MIRT, though more spontaneous reports of knee pain were observed ( n = 14) compared to BFR ( n = 3). BFR may have lower efficacy than MIRT in this context-though a fully-powered trial is needed to definitively address this hypothesis.

Purpose: To determine whether differential kinematics, kinetics, rates of energy use, and cardiopulmonary responses occur during running with water bottles and bottle belt holders compared with running only., Methods: Trained runners (N = 42; age 27.2 [6.4] y) ran on an instrumented treadmill for 4 conditions in a randomized order: control run (CON), handheld full water bottle (FULL; 16.9 fluid oz; 454 g), handheld half-full water bottle (HALF; 8.4 fluid oz; 227 g), and waist-worn bottle belt holder (BELT; hydration belt; 676 g). Gas exchange was measured using a portable gas analyzer. Kinetic and kinematic responses were determined by standard 3-dimensional videographic techniques. Interactions of limb side (right and left) by study condition (CON, FULL, HALF, and BELT) were tested for rates of oxygen use and energy expenditure and kinematic and kinetic parameters., Results: No significant limb-side × condition interactions existed for rates of oxygen use or energy expenditure. A significant interaction occurred with sagittal elbow flexion (P < .001). Transverse pelvic-rotation excursions differed on average 3.8° across conditions. The minimum sagittal hip-flexion moment was higher in the right leg in the HALF and BELT conditions compared with CON (P < .001)., Conclusions: Carrying water by hand or on the waist does not significantly change the kinematics of running motion, rates of oxygen use and energy expenditure, or cardiopulmonary measures over short durations. Runners likely make adjustments to joint moments and powers that preserve balance and protect the lower-extremity joints while maintaining rates of oxygen use and energy expenditure.

Lacrosse is a fast-paced game that incorporates elements from multiple sports, such as soccer, basketball, baseball, tennis, and hockey. The sport involves rapid changes of direction, endurance, sprinting, physical contact, rotational movement, passing, and shooting. Passing and shooting are further complicated by having a weighted object (ball) at the end of a long moment arm (crosse) which places increased stress on the body segments. Thus, it is important to properly prepare for sport participation by improving strength, endurance, and dynamic stability of the postural and core stability muscles. Because high mechanical loads are experienced during play, (re)establishment of symmetric strength and flexibility is essential for rehabilitation and injury prevention. This article will focus on the musculoskeletal demands placed on the body in lacrosse, the importance of core strength and dynamic stability to prevent injury, and the elements of both prehabilitation and rehabilitation programs to properly prepare the athlete for participation.