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The objective was to assess how patellofemoral loads (joint force and stress) change while lunging with step length and step height variations. Sixteen participants performed a forward lunge using short and long steps at ground level and up to a 10-cm platform. Electromyography, ground reaction force, and 3D motion were captured, and patellofemoral loads were calculated as a function of knee angle. Repeated-measures 2-way analysis of variance (P < .05) was employed. Patellofemoral loads in the lead knee were greater with long step at the beginning of landing (10°–30° knee angle) and the end of pushoff (10°–40°) and greater with short step during the deep knee flexion portion of the lunge (50°–100°). Patellofemoral loads were greater at ground level than 10-cm platform during lunge descent (50°–100°) and lunge ascent (40°–70°). Patellofemoral loads generally increased as knee flexion increased and decreased as knee flexion decreased. To gradually increase patellofemoral loads, perform forward lunge in the following sequence: (1) minimal knee flexion (0°–30°), (2) moderate knee flexion (0°–60°), (3) long step and deep knee flexion (0°–100°) up to a 10-cm platform, and (4) long step and deep knee flexion (0°–100°) at ground level.

The current study aimed to investigate the long-term effects of receiving post-amputation physical therapy (PT) on individuals' self-reported functional outcomes and quality of life in middle-aged to older adults with lower limb amputation (LLA). Further, we qualitatively explored the patients' perception and experience of PT post-amputation. We assessed participants' functional outcomes using Short-Form Health Survey, Prosthetic Evaluation Questionnaire-Physical Mobility portion, and Fear of Falling Avoidance Behavior Questionnaire. Furthermore, participants' experience and perception to PT were assessed through in-person interviews guided by the custom Amputation Patient Perception Survey. Functional outcome scores were compared between participants who have (Yes-PT) and have not (No-PT) received PT following their amputations, controlling for age. Perception to PT was qualitatively analyzed. Out of the 70 participants, 56 had received PT (80%) following amputation. Functional outcome scores were not significantly different between Yes-PT and No-PT groups. Among participants in the Yes-PT group, 84% expressed overall positive perception toward their post-amputation PT care. Main positive and negative perceptions were related to outcome/benefits and unfulfilled needs/lack of benefits, respectively. Participants with LLA generally expressed a positive perception of PT. However, no significant long-term benefits were found. We recommend goal-directed intervention with patient engagement to improve care experience.

Curricular guidelines do not exist currently for content related to amputation rehabilitation and prosthetics in entry-level physical therapy education programs. Documents exist to provide context, but before guidelines can be written, the current content of entry-level physical therapist professional education programs must be known.Faculty members teaching amputation rehabilitation and prosthetics at 225 accredited physical therapist education programs in the United States were recruited via e-mail. A link to the survey was emailed to faculty to report on amputation rehabilitation and prosthetics curricula, faculty qualifications, attitudes, and experiences.Faculty from 74 (32.9%) programs responded to the survey in part or whole. Faculty rated student competence on a scale of 0 (not taught), and 1 (not competent) to 5 (competent). In the areas of lower extremity amputation care, transtibial and transfemoral gait deviations,63/68 respondents rated students 3 or greater. In contrast, 38/68 faculty rated students as3 in the area of upper extremity amputation care, with 12 responding "not taught."Variability was noted between programs in hours of exposure, faculty-rated student competence, and minimum skill requirements. These results serve to describe the current level of training of entry-level graduates, assess and compare existing curricula, and provide guidance for further curricular development.

Background. Chronic kidney disease (CKD) is associated with an elevated risk of all-cause mortality, with cardiovascular death being extensively investigated. However, non-cardiovascular mortality represents the biggest percentage, showing an evident increase in recent years. Klotho is a gene highly expressed in the kidney, with a clear influence on lifespan. Low levels of Klotho have been linked to CKD progression and adverse outcomes. Single nucleotide polymorphisms (SNPs) of the Klotho gene have been associated with several diseases, but studies investigating the association of Klotho SNPs with noncardiovascular death in CKD populations are lacking. Methods. The main aim of this study was to assess whether 11 Klotho SNPs were associated with non-cardiovascular death in a subpopulation of the National Observatory of Atherosclerosis in Nephrology (NEFRONA) study (n ¼ 2185 CKD patients). Results. After 48 months of follow-up, 62 cardiovascular deaths and 108 non-cardiovascular deaths were recorded. We identified a high non-cardiovascular death risk combination of SNPs corresponding to individuals carrying the most frequent allele (G) at rs562020, the rare allele (C) at rs2283368 and homozygotes for the rare allele (G) at rs2320762 (rs562020 GG/AG þ rs2283368 CC/CT þ rs2320762 GG). Among the patients with the three SNPs genotyped (n ¼ 1016), 75 (7.4%) showed this combination. Furthermore, 95 (9.3%) patients showed a low-risk combination carrying all the opposite genotypes (rs562020 AA þ rs2283368 TT þ rs2320762 GT/TT). All the other combinations [n ¼ 846 (83.3%)] were considered as normal risk. Using competing risk regression analysis, we confirmed that the proposed combinations are independently associated with a higher fhazard ratio [HR] 3.28 [confidence interval (CI) 1.51-7.12]g and lower [HR 6 × 10-6 (95% CI 3.3 × 10-7-1.1 × 10-5)] risk of suffering a non-cardiovascular death in the CKD population of the NEFRONA cohort compared with patients with the normal-risk combination. Conclusions. Determination of three SNPs of the Klotho gene could help in the prediction of non-cardiovascular death in CKD. © The Author(s) 2020. Published by Oxford University Press on behalf of ERA-EDTA. This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0/), which permits non-commercial re-use, distribution, and reproduction in any medium, provided the original work is properly cited.

Chronic kidney disease (CKD) is a major risk factor for end-stage renal disease, cardiovascular disease and premature death. Despite classical clinical risk factors for CKD and some genetic risk factors have been identified, the residual risk observed in prediction models is still high. Therefore, new risk factors need to be identified in order to better predict the risk of CKD in the population. Here, we analyzed the genetic association of 79 SNPs of proteins associated with mineral metabolism disturbances with CKD in a cohort that includes 2,445 CKD cases and 559 controls. Genotyping was performed with matrix assisted laser desorption ionizationtime of flight mass spectrometry. We used logistic regression models considering different genetic inheritance models to assess the association of the SNPs with the prevalence of CKD, adjusting for known risk factors. Eight SNPs (rs1126616, rs35068180, rs2238135, rs1800247, rs385564, rs4236, rs2248359, and rs1564858) were associated with CKD even after adjusting by sex, age and race. A model containing five of these SNPs (rs1126616, rs35068180, rs1800247, rs4236, and rs2248359), diabetes and hypertension showed better performance than models considering only clinical risk factors, significantly increasing the area under the curve of the model without polymorphisms. Furthermore, one of the SNPs (the rs2248359) showed an interaction with hypertension, being the risk genotype affecting only hypertensive patients. We conclude that 5 SNPs related to proteins implicated in mineral metabolism disturbances (Osteopontin, osteocalcin, matrix gla protein, matrix metalloprotease 3 and 24 hydroxylase) are associated to an increased risk of suffering CKD.

Summary Objective This study aimed to investigate the associations between patellofemoral cartilage T 1ρ and T 2 relaxation times and knee flexion moment (KFM) and KFM impulse during gait. Method Knee magnetic resonance (MR) images were obtained from 99 subjects with and without patellofemoral joint (PFJ) osteoarthritis (OA), using fast spin-echo, T 1ρ and T 2 relaxation time sequences. Patellar and trochlear cartilage relaxation times were computed for the whole cartilage, and superficial and deep layers (laminar analysis). Subjects also underwent three-dimensional (3D) gait analysis. Peak KFM and KFM impulse were calculated during the stance phase. Linear regressions were used to examine whether cartilage relaxation times were associated with knee kinetics during walking while adjusting age, sex, body mass index (BMI) and walking speed. Results Higher peak KFM and KFM impulse were significantly related to higher T 1ρ and T 2 relaxation times of the trochlear and patellar cartilage, with standardized regression coefficients ranging from 0.21 to 0.28. Laminar analysis showed that overall the superficial layer of patellofemoral cartilage showed stronger associations with knee kinetics. Subgroup analysis revealed that in subjects with PFJ OA, every standard deviation change in knee kinetics was related to greater increases in PFJ cartilage T 1ρ and T 2 (standardized coefficients: 0.29 to 0.41). Conversely, in subjects without OA, weaker relationships were observed between knee kinetics and PFJ cartilage T 1ρ and T 2 . Conclusions Our findings suggest that increased peak KFM and KFM impulse were related to worse cartilage health at the PFJ. This association is more prominent in superficial layer cartilage and cartilage with morphological lesions.

Background Patellofemoral joint osteoarthritis is a highly prevalent disease and an important source of pain and disability. Nonetheless, biomechanical risk factors associated with this disease remain unclear. The purpose of this study was to compare biomechanical factors that are associated with patellofemoral joint loading during walking between individuals with isolated patellofemoral joint osteoarthritis and no osteoarthritis. Methods MR images of the knee were obtained using a 3D fast-spin echo sequence to identify patellofemoral joint cartilage lesions. Thirty-five subjects with isolated patellofemoral joint osteoarthritis (29 females) and 35 control subjects (21 females) walked at a self-selected speed and as fast as possible. Peak knee flexion moment, flexion moment impulse and peak patellofemoral joint stress during the first and second halves of the stance phase were compared between groups. Findings When compared to the controls, individuals with patellofemoral joint osteoarthritis demonstrated significantly higher peak knee flexion moment (P = .03, Eta2 = .07), higher knee flexion moment impulse (P = .03, Eta2 = .07) and higher peak patellofemoral joint stress (P = .01, Eta2 = .10) during the second half of the stance phase. No significant group difference was observed during the first half of the stance phase. Interpretation Findings of this study suggest that increased mechanical loading (i.e. knee flexion moment, impulse and patellofemoral joint stress) during the second half of the stance phase is associated with patellofemoral joint osteoarthritis. Prevention and rehabilitation programs for patellofemoral joint osteoarthritis may focus on reducing the loading on the patellofemoral joint, specifically during late stance.

Prospective cross-sectional study.To compare knee muscle morphology and voluntary neuromuscular control in individuals who sustained an anterior cruciate ligament (ACL) injury and were identified as being capable of avoiding surgery (potential copers) and those who were recommended for surgery (noncopers), within 6 months of injury.Quadriceps atrophy and poor neuromuscular control have been found in noncopers. However, the reasons why some noncopers may be able to avoid surgery remain elusive.Twenty participants (10 ACL-deficient noncopers and 10 ACL-deficient potential copers) were included in this study. Axial spin-echo, T1-weighted magnetic resonance imaging data of the lower extremities were captured. The volume and maximum cross-sectional area (CSA) of each muscle of the quadriceps and hamstrings were calculated following digital reconstruction. In addition, voluntary neuromuscular control was evaluated using an established target-matching task that required participants to produce static isometric loads across the knee joint. Electromyography was acquired from 5 muscles as participants performed the target-matching task. Circular statistics were used to calculate a specificity index to describe how well focused each muscle was activated toward its primary direction of muscle action. The ACL-deficient limb was then compared to the uninvolved limb of the noncopers and potential copers.The vasti (vastus medialis and vastus intermedius) of the involved limb of the noncopers were significantly smaller (P.031) in comparison to those of their uninvolved limb. The potential copers' vastus lateralis maximum CSA (P = .047), total quadriceps muscle volume (P = .020) and maximum CSA (P = .015), and quadriceps-hamstring ratio volume (P = .021) and maximum CSA (P = .007) demonstrated quadriceps atrophy. However, only the ACL-deficient limb of the older (mean ± SD age, 27.4 ± 11.4 versus 19.9 ± 3.3 years; P = .032) and lower-activity-level (3.3 ± 0.5 versus 3.6 ± 0.5; P = .098) noncoper group demonstrated reduced rectus femoris (P = .057) and lateral hamstring (P = .064) neuromuscular control in comparison to their uninvolved limb.These findings suggest that quadriceps and hamstring muscle function, rather than muscle size, may be an important factor in the varied response early after ACL injury.

Summary Objectives To compare thigh muscle intramuscular fat (intraMF) fractions and area between people with and without knee radiographic osteoarthritis (ROA); and to evaluate the relationships of quadriceps adiposity and area with strength, function and knee magnetic resonance imaging (MRI) lesions. Methods Ninety six subjects (ROA: Kellgren–Lawrence (KL) > 1; n = 30, control: KL = 0, 1; n = 66) underwent 3-T MRI of the thigh muscles using chemical shift-based water/fat MRI (fat fractions) and the knee (clinical grading). Subjects were assessed for isometric/isokinetic quadriceps/hamstrings strength, function Knee injury and Osteoarthritis Outcome Score (KOOS), stair climbing test (SCT), and 6-minute walk test (6MWT). Thigh muscle intraMF fractions, muscle area and strength, and function were compared between controls and ROA subjects, adjusting for age. Relationships between measures of muscle fat/area with strength, function, KL and lesion scores were assessed using regression and correlational analyses. Results The ROA group had worse KOOS scores but SCT and 6MWT were not different. The ROA group had greater quadriceps intraMF fraction but not for other muscles. Quadriceps strength was lower in ROA group but the area was not different. Quadriceps intraMF fraction but not area predicted self-reported disability. Aging, worse KL, and cartilage and meniscus lesions were associated with higher quadriceps intraMF fraction. Conclusion Quadriceps intraMF is higher in people with knee OA and is related to symptomatic and structural severity of knee OA, whereas the quadriceps area is not. Quadriceps fat fraction from chemical shift-based water/fat MR imaging may have utility as a marker of structural and symptomatic severity of knee OA disease process.

Different functional roles for the hands have been demonstrated, however leg control is not as well understood. The purpose of the present study was to evaluate bilateral knee neuromuscular control to determine if the limb receiving greater attention would have more well-tuned control compared to an unattended limb. Surface electrodes were placed on seven muscles of each limb, before standing on two force platforms. Visual feedback was given of the forces and moments of the "focus limb," but not the "unattended limb." Static isometric forces were matched with their focus limb, requiring their unattended limb to push in the opposite direction, using a combination of forward–backward–medial–lateral shear forces while muscle activity was collected bilaterally. There was a significant main effect for limb task ( p =0.02), with the medial hamstrings being more specific ( p =0.001) while performing the unattended limb and the lateral hamstring being more well-tuned ( p =0.007) while performing the focus limb task. The focus limb's medial and lateral gastrocnemius were principally active in the forwards direction, but only the unattended limb's lateral gastrocnemius was active in the backwards direction. Findings suggest unique neuromuscular control strategies are used for the legs depending on limb task.

Synopsis There is a growing body of evidence documenting loads applied to the anterior cruciate ligament (ACL) for weight-bearing and non—weight-bearing exercises. ACL loading has been quantified by inverse dynamics techniques that measure anterior shear force at the tibiofemoral joint (net force primarily restrained by the ACL), ACL strain (defined as change in ACL length with respect to original length and expressed as a percentage) measured directly in vivo, and ACL tensile force estimated through mathematical modeling and computer optimization techniques. A review of the biomechanical literature indicates the following: ACL loading is generally greater with non—weight-bearing compared to weight-bearing exercises; with both types of exercises, the ACL is loaded to a greater extent between 10° to 50° of knee flexion (generally peaking between 10° and 30°) compared to 50° to 100° of knee flexion; and loads on the ACL change according to exercise technique (such as trunk position). Squatting with excessiv...

Purpose: The purpose of this study was to compare cruciate ligament forces between the forward lunge with a short step (forward lunge short) and the forward lunge with a long step (forward lunge long). Methods: Eighteen subjects used their 12-repetition maximum weight while performing the forward lunge short and long with and without a stride. EMG, force, and kinematic variables were input into a biomechanical model using optimization, and cruciate ligament forces were calculated as a function of knee angle. A two-factor repeated-measure ANOVA was used with a Bonferroni adjustment (P < 0.0025) to assess differences in cruciate forces between lunging techniques. Results: Mean posterior cruciate ligament (PCL) forces (69-765 N range) were significantly greater (P < 0.001) in the forward lunge long compared with the forward lunge short between 0[degrees] and 80[degrees] knee flexion angles. Mean PCL forces (86-691 N range) were significantly greater (P < 0.001) without a stride compared with those with a stride between 0[degrees] and 20[degrees] knee flexion angles. Mean anterior cruciate ligament (ACL) forces were generated (0-50 N range between 0[degrees] and 10[degrees] knee flexion angles) only in the forward lunge short with stride. Conclusions: All lunge variations appear appropriate and safe during ACL rehabilitation because of minimal ACL loading. ACL loading occurred only in the forward lunge short with stride. Clinicians should be cautious in prescribing forward lunge exercises during early phases of PCL rehabilitation, especially at higher knee flexion angles and during the forward lunge long, which generated the highest PCL forces. Understanding how varying lunging techniques affect cruciate ligament loading may help clinicians prescribe lunging exercises in a safe manner during ACL and PCL rehabilitation.

Controlled laboratory biomechanics study using a repeated-measures, counterbalanced design.To compare patellofemoral joint force and stress between a short- and long-step forward lunge both with and without a stride.Although weight-bearing forward-lunge exercises are frequently employed during rehabilitation for individuals with patellofemoral joint syndrome, patellofemoral joint force and stress and how they change with variations of the lunge exercise are currently unknown.Eighteen subjects used their 12-repetition maximum weight while performing a short- and long-step forward lunge both with and without a stride. Electromyography, ground reaction force, and kinematic variables were put into a biomechanical optimization model, and patellofemoral joint force and stress were calculated as a function of knee angle.Visual observation of the data show that during the forward lunge, patellofemoral joint force and stress increased progressively as knee flexion increased, and decreased progressively as knee flexion decreased. Between 70 degrees and 90 degrees of knee flexion, patellofemoral joint force and stress were significantly greater when performing a forward lunge with a short step compared to a long step (P.025). Between 10 degrees and 40 degrees of knee flexion, patellofemoral joint force and stress were significantly greater when performing a forward lunge with a stride compared to without a stride (P.025).When the goal is to minimize patellofemoral joint force and stress during the forward lunge performed between 0 degrees to 90 degrees knee angles, it may be prudent to perform the lunge with a long step compared to a short step and without a stride compared to with a stride, because patellofemoral joint force and stress magnitudes were greater with a short step compared to a long step at higher knee flexion angles and were greater with a stride compared to without a stride at lower knee flexion angles.