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Body mass index (BMI) and history of anterior cruciate ligament reconstruction (ACLR) independently influence gait biomechanics and knee osteoarthritis risk, but the interaction between these factors is unclear. The purpose of this study was to compare gait biomechanics between individuals with and without ACLR, and with and without overweight/obesity. We examined 104 individuals divided into four groups: with and without ACLR, and with low or high BMI (n = 26 per group). Three-dimensional gait biomechanics were evaluated at preferred speed. The peak vertical ground reaction force, knee flexion angle and excursion, external knee flexion moment, and external knee adduction moment were extracted for analysis. Gait features were compared between groups using 2 (with and without overweight/obesity) × 2 (with and without ACLR) analysis of variance. Primary findings indicated that those with ACLR and high BMI had a larger external knee adduction moment compared with those with low BMI and with (p = 0.004) and without ACLR (p = 0.005), and compared with those without ACLR and high BMI (p = 0.001). The main effects of ACLR and BMI group were found for the knee flexion moment, and those with ACLR and with high BMI had lower knee flexion moments compared with those without ACLR (p = 0.031) and with low BMI (p = 0.021), respectively. Data suggest that individuals with ACLR and high BMI may benefit from additional intervention targeting the knee adduction moment. Moreover, lower external knee flexion moments in those with high BMI and ACLR were consistent, but high BMI did not exacerbate deficits in the knee flexion moment in those with ACLR. [Correction added on 9 November 2022, after first online publication: In the preceding sentence, for clarity, the words "reductions in the lower" was removed from the initial sentence to read "Moreover, lower external knee flexion moments".]., (© 2022 Orthopaedic Research Society. Published by Wiley Periodicals LLC.)

Background: Submaximal endurance exercise has been shown to cause elevated gastrointestinal permeability, injury, and inflammation, which may negatively impact athletic performance and recovery. Preclinical and some clinical studies suggest that flavonoids, a class of plant secondary metabolites, may regulate intestinal permeability and reduce chronic low-grade inflammation. Consequently, the purpose of this study was to determine the effects of supplemental flavonoid intake on intestinal health and cycling performance., Materials and Methods: A randomized, double-blind, placebo-controlled crossover trial was conducted with 12 cyclists (8 males and 4 females). Subjects consumed a dairy milk-based, high or low flavonoid (490 or 5 mg) pre-workout beverage daily for 15 days. At the end of each intervention, a submaximal cycling trial (45 min, 70% VO2max) was conducted in a controlled laboratory setting (23°C), followed by a 15-minute maximal effort time trial during which total work and distance were determined. Plasma samples were collected pre- and post-exercise (0h, 1h, and 4h post-exercise). The primary outcome was intestinal injury, assessed by within-subject comparison of plasma intestinal fatty acid-binding protein. Prior to study start, this trial was registered at ClinicalTrials.gov (NCT03427879)., Results: A significant time effect was observed for intestinal fatty acid binding protein and circulating cytokines (IL-6, IL-10, TNF-α). No differences were observed between the low and high flavonoid treatment for intestinal permeability or injury. The flavonoid treatment tended to increase cycling work output (p = 0.051), though no differences were observed for cadence or total distance., Discussion: Sub-chronic supplementation with blueberry, cocoa, and green tea in a dairy-based pre-workout beverage did not alleviate exercise-induced intestinal injury during submaximal cycling, as compared to the control beverage (dairy-milk based with low flavonoid content)., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2022 Kung 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.)

Reactive balance, a critical automatic movement pattern in response to a perturbation, is directly linked to fall prevention in older adults. Various exercise interventions have been broadly performed to improve reactive balance and thus prevent falls. Curiously, aquatic exercises have been suggested as an effective balance intervention and a safer alternative to exercises on dry land yet the efficacy of aquatic exercises on reactive balance has not been formally investigated. The present clinical trial aims to identify if skills acquired during aquatic exercise are more effectively transferred to a reactive balance task than land exercise. This study is designed as a double-blinded, randomized controlled clinical trial. Forty-four older adults aged 65 years or above who meet the eligibility criteria will be recruited and randomized into an aquatic exercise group or land exercise group. Each group will participate in the same single bout intervention that includes a ball throwing and catching task. A modified lean-and-release test will be implemented on land immediately before, after, and one week after the single bout intervention. The outcomes will include reaction time, rapid response accuracy, and mini-BESTest scores obtained from stepping and grasping reactions. All statistical analyses will be conducted using an intention-to-treat approach. Our conceptual hypothesis is that participants in the aquatic exercise group will demonstrate more improved outcome scores in the lean-and-release test when compared to those in the land exercise group. The results of the present study are expected to provide evidence to support the benefits of aquatic exercises for improving reactive balance in older adults. Further, participants may find aquatic exercises safer and more motivating, thus encouraging them to participate in further aquatic exercise programs., Competing Interests: The authors have declared that no competing interests exist.

Background: Individuals with obesity have impaired gait and muscle function that may contribute to reduced mobility and increased fall risk., Research Questions: (1) what is the difference in spatiotemporal gait parameters and joint kinetics between individuals with and without obesity; (2) what is the association between spatiotemporal gait parameters, joint kinetics, and quadriceps function?, Methods: Forty-eight young adults with obesity (BMI = 33.0 ± 4.1 kg/m 2 ) and 48 without obesity (BMI = 21.6 ± 1.7 kg/m 2 ) completed assessments of quadriceps function (peak torque and early/late rate of torque development (RTD)) and walking biomechanics at self-selected speed. Spatiotemporal gait parameters (stance time, double support time, double support to stance ratio, step width, step length, cadence, and gait stability ratio (GSR)) and joint kinetics (total support moment, and relative contribution from extensor moments) were compared using one-way MANOVAs. Partial correlation examined the association between the total support moment and quadriceps function, and spatiotemporal gait parameters controlling for sex and speed., Results: Individuals with obesity walked with longer stance (p = 0.01), longer double-limb support (p < 0.001), wider steps (p < 0.001), lower cadence (p = 0.03), and a greater absolute (p < 0.001) but lesser normalized total support moment (p = 0.03) compared with adults without obesity. In those with obesity, greater PT was associated with less double limb support (p = 0.011) and smaller double support to stance ratio (p = 0.006); greater early RTD was associated with less double limb support (r = -0.455, p = 0.0021), less stance time (r = -0.384, p = 0.008), and a smaller double support to stance ratio (r = -0.371, p = 0.011). In those without obesity, a larger total support moment was associated with longer step length (r = 0.512, p < 0.001), lesser cadence (r = -0.497, p < 0.001), and smaller GSR (-0.460, p = 0.001)., Significance: Individuals with obesity walk with altered spatiotemporal gait parameters and joint kinetics that may compromise stability. Extended periods of support may be a strategy used by individuals with obesity to increase stability during gait and accomodate insufficient quadriceps function., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Background: Obesity and female sex are independent risk factors for knee osteoarthritis and also influence gait mechanics. However, the interaction between obesity and sex on gait mechanics is unclear, which may have implications for tailored gait modification strategies., Research Question: The purpose of this study was to examine the influence of obesity and sex on sagittal and frontal plane knee mechanics during gait in young adults., Methods: Forty-eight individuals with (BMI = 33.03 ± 0.59; sex:50 % female; age:21.9 ± 2.6 years) and 48 without obesity (BMI:21.59 ± 0.25; sex:50 % female; age:22.9 ± 3.57 years) matched on age and sex completed over-ground gait assessments at a self-selected speed. Two (BMI) by two (sex) analysis of variance was used to compare knee biomechanics during the first half of stance in the sagittal (knee flexion moment [KFM] and excursion [KFE]) and frontal plane (first peak knee adduction moment [KAM], knee varus velocity [KVV])., Results: We observed a BMI by sex interaction for normalized KFM (P = 0.03). Females had smaller normalized KFM compared to males (P = 0.03), but only in individuals without obesity. Males without obesity had larger normalized KFM compared to males with obesity (P = 0.01), while females did not differ between BMI groups. We observed main effects of sex and BMI group, where females exhibited greater normalized KAM (P < 0.01) and KVV (P < 0.01) compared to males, and individuals with obesity walked with greater KVV compared to those without obesity (P < 0.01). All absolute joint moments were greater in individuals with obesity (all P<0.01) and males had greater absolute KFM compared to females (P < 0.01)., Significance: We observed sex differences in gait mechanics, however, KFM differences between males and females were only evident in individuals without obesity. Further, females and individuals with obesity had a larger KAM and KVV, which may contribute to larger medial compartment joint loading., (Copyright © 2020 Elsevier B.V. All rights reserved.)

This study compared femoral cartilage characteristics between age- and sex-matched individuals with (n = 48, age = 22.8 ± 3.5 years; body mass index [BMI] = 33.1 ± 4.1 kg/m 2 ) and without obesity (n = 48 age = 22.0 ± 2.6 years; BMI = 21.7 ± 1.7 kg/m 2 ) and evaluated the associations between body composition, quadriceps function, and gait kinetics with femoral cartilage characteristics. Medial and lateral femoral cartilage thickness, medial:lateral thickness ratio and medial and lateral cartilage echo intensity were measured using ultrasound imaging. Body composition was assessed using air displacement plethysmography. Quadriceps function was assessed via maximal isometric knee extension. Three-dimensional gait biomechanics were recorded to extract peak external knee flexion and adduction moments, and peak loading rate of the vertical ground reaction force. Cartilage outcomes were compared between groups using one-way multivariate analysis of variance. Stepwise moderated regression evaluated the association between body composition, quadriceps function, and gait kinetics with femoral cartilage outcomes in individuals with and without obesity. Medial (75.24 vs 65.84; P < .001, d = 1.02) and lateral (58.81 vs 52.22; P < .001, d = 0.78) femoral cartilage echo intensity were higher in individuals with compared with those without obesity. A higher body fat percentage was associated with higher medial and lateral cartilage echo intensity (ΔR 2  = 0.09-0.12) in individuals with obesity. A higher knee adduction moment was associated with a larger medial:lateral thickness ratio (ΔR 2  = 0.09) in individuals without obesity. No associations were found between quadriceps function and cartilage outcomes. These findings suggest that high body fat in adults with obesity is associated with cartilage echo intensity. The obese body mass index was also associated with a lack of a positive relationship between cartilage thickness and joint loading during walking., (© 2020 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.)

Background: Balance impairments are the leading causes of falls in older adults. Aquatic-based exercises have been broadly practiced as an alternative to land-based exercises; however, the effects on dynamic balance have not been comprehensively reviewed and compared to land exercises. Thus, the purpose of this systematic review and meta-analysis was to compare the effectiveness of aquatic exercises (AE) to land exercises (LE) on dynamic balance in older adults., Methods: Electronic databases (PubMed, MEDLINE, CINAHL, SPORTDiscus, psycINFO), from inception to November 2019, were searched. Studies met the following eligibility criteria: Randomized controlled trials, English language, older adults aged 65 years or older, a minimum of one AE and LE group, at least one assessment for dynamic balance. For the meta-analysis, the effect sizes of dynamic balance outcomes were calculated using a standardized mean difference (SMD) and a 95% confidence interval (CI)., Results: A total of 11 trials met the inclusion criteria, and 10 studies were eligible for the meta-analysis. The meta-analysis presented that older adults in AE groups demonstrated comparable enhancements in dynamic steady-state balance (SMD = - 0.24; 95% CI, -.81 to .34), proactive balance (SMD = - 0.21; 95% CI, -.59 to .17), and balance test batteries (SMD = - 0.24; 95% CI, -.50 to .03) compared with those in LE groups., Conclusions: AE and LE have comparable impacts on dynamic balance in older adults aged 65 years or older. Thus, this review provides evidence that AE can be utilized as a reasonable alternative to LE to improve dynamic balance and possibly reduce the risk of falls.

Context: Ultrasound imaging provides a cost-effective method of measuring quadriceps morphology, which may be related to self-reported function after anterior cruciate ligament reconstruction (ACLR)., Objective: To compare quadriceps morphology and strength between limbs in individuals with ACLR and matched control limbs and determine their associations with self-reported function., Design: Cross-sectional study., Setting: Research laboratory., Patients or Other Participants: Forty-two individuals with ACLR (females = 66%; age = 21.8 ± 2.6 years; time since ACLR = 50.5 ± 29.4 months) and 37 controls (females = 73%; age = 21.7 ± 1.2 years)., Main Outcome Measure(s): Quadriceps peak torque (PT) and rate of torque development were assessed bilaterally. Ultrasonography was used to measure the cross-sectional area (CSA) and echo intensity (EI) of the rectus femoris, vastus lateralis (VL), and vastus medialis. Self-reported function was assessed via the International Knee Documentation Committee (IKDC) score and Knee Injury and Osteoarthritis Outcome Score (KOOS) subscales. Paired-samples t tests were calculated to compare involved and uninvolved limbs. Independent t tests were conducted to compare groups (α = .05). Linear regression was performed to analyze associations between quadriceps function and self-reported function after accounting for time since ACLR, activity level, and sex, and models for EI added subcutaneous fat as a covariate., Results: Isometric PT did not differ between limbs or groups. Involved limbs had a lower rate of torque development compared with the control ( P = .01) but not the uninvolved limbs ( P = .08). Vastus lateralis CSA was smaller in the involved than in the uninvolved ( P < .01) but not the control limbs ( P = .10). Larger VL CSA (Δ R 2 = 0.103) and lower VL EI (Δ R 2 = 0.076) were associated with a higher IKDC score ( P < .05). Larger VL CSA was associated with greater KOOS Symptoms (Δ R 2 = 0.09, P = .043) and Sport and Recreation (Δ R 2 = 0.125, P = .014) scores. Lower VL EI was associated with higher KOOS Symptoms (Δ R 2 = 0.104, P = .03) and Quality of Life (Δ R 2 = 0.113, P = .01) scores. Quadriceps PT and rate of torque development were not associated with IKDC or KOOS subscale scores., Conclusions: Quadriceps morphology was associated with self-reported function in individuals with ACLR and may provide unique assessments of quadriceps function.

Purpose: Obesity influences gait and muscle function, which may contribute to knee osteoarthritis. This study aimed 1) to compare gait biomechanics and quadriceps function between individuals with and without obesity and 2) to examine the association between quadriceps function and gait biomechanics., Methods: Forty-eight individuals with and 48 without obesity participated and were matched on age and sex. Gait biomechanics at standardized and self-selected speeds were used to assess peak vertical ground reaction force (vGRF), vertical loading rate (vLR), internal knee extension moment (KEM), peak knee flexion angle (KFA), knee flexion excursion (KFE), and knee joint stiffness. Quadriceps function was assessed using peak isometric strength (peak torque), early (RTD100) and late (RTD200) rate of torque development (RTD), and vastus lateralis cross-sectional area (CSA) and echo intensity (EI)., Results: When normalized to fat-free mass, individuals with obesity had lower RTD100 (P = 0.04) and RTD200 (P = 0.02) but higher vastus lateralis CSA (P < 0.01) and EI (P < 0.01) compared with normal weight controls. The group-speed interaction was significant for normalized vGRF (P < 0.01), normalized vLR (P = 0.02), normalized KEM (P = 0.03), and normalized knee joint stiffness (P = 0.02). Post hoc analyses indicate a smaller normalized vGRF and normalized KEM, and lower knee joint stiffness in individuals with obesity compared with normal weight controls at self-selected speed. There were main effects of speed for all kinematic and kinetic variables, and body mass index group for all absolute kinetic variables as well as normalized vGRF (all P < 0.001). A lower vastus lateralis EI (P = 0.04) and greater RTD100 (P < 0.01) were associated with a larger KEM in individuals with obesity., Conclusion: Individuals with obesity have quadriceps dysfunction that is weakly associated with KEM during walking. Exercise interventions that improve quadriceps function may improve walking mechanics.

Background: Following anterior cruciate ligament reconstruction (ACLR), individuals have quadriceps muscle impairments that influence gait mechanics and may contribute to an elevated risk of knee osteoarthritis., Objectives: To compare running mechanics and quadriceps function between individuals who have undergone ACLR and those in a control group, and to evaluate the association between quadriceps function and running mechanics., Methods: In this controlled, cross-sectional laboratory study, 38 individuals who previously underwent primary unilateral ACLR (mean ± SD time since reconstruction, 48.0 ± 25.0 months) were matched to 38 control participants based on age, sex, and body mass index, and underwent assessments of quadriceps muscle performance and running biomechanics. Quadriceps muscle performance was assessed via isokinetic and isometric knee extension peak torque and rate of torque development (RTD) over 2 time frames: 0 to 100 milliseconds (RTD100) and 0 to 200 milliseconds (RTD200). Running evaluation included assessment of the knee flexion angle (KFA), knee extension moment (KEM), rate of knee extension moment (RKEM), vertical instantaneous loading rate, and vertical impact peak., Results: On average, there was a smaller KFA (P = .016) in the involved limb compared to the uninvolved limb in the ACLR group. Compared to limbs in the control group, involved limbs in the ACLR group had lower RTD100 (P = .015), lower peak torque at 60°/s (P = .007), lower peak torque at 180°/s (P = .016), smaller KFA (P<.001), lower KEM (P = .001), lower RKEM (P = .004), and higher vertical instantaneous loading rate (P = .016). Compared to limbs in the control group, uninvolved limbs in the ACLR group had lower RTD100 (P = .003), lower peak torque at 60°/s (P = .017), and smaller KFA (P = .01). For the involved limbs in the ACLR group, there was a low correlation between isokinetic peak torque at 180°/s and RKEM (r = 0.38, P = .01), and a negligible correlation between RTD100 and RKEM (r = 0.26, P<.05). No differences were found in isometric strength for any comparison., Conclusion: Individuals who have undergone ACLR have bilateral alterations in running mechanics that are weakly associated with diminished quadriceps muscle performance. J Orthop Sports Phys Ther 2018;48(12):960-967. Epub 22 Jul 2018. doi:10.2519/jospt.2018.8170.

Background: Individuals with anterior cruciate ligament reconstruction (ACLR) are at greater risk for knee osteoarthritis, which may be in part due to altered gait biomechanics. Articular cartilage thickness is typically imaged using magnetic resonance imaging, which is costly and lacks portability. Ultrasonography may provide an alternative imaging method for articular cartilage. It is unclear if ultrasonographic measurements of cartilage thickness are associated with gait biomechanics in individuals with ACLR., Research Question: To evaluate the association between sagittal and frontal plane knee mechanics during gait and resting femoral cartilage thickness from ultrasonography., Methods: Twenty-five females with ACLR (age = 21.7 ± 2.6 years, time since ACLR = 60.6 ± 24.8 months) completed assessments of walking biomechanics and resting femoral cartilage thickness. Linear regression examined the association between gait biomechanics and cartilage thickness at the medial (MC) and lateral (LC) femoral condyles, and intercondylar notch (IC) after accounting for time since ACLR, meniscal injury, and gait speed., Results: In the ACLR limb, larger vertical ground reaction force (ΔR 2  = 0.21, pΔ = 0.03), knee flexion angle (ΔR 2  = 0.15, pΔ = 0.05), knee flexion excursion (KFE) (ΔR 2  = 0.16, pΔ = 0.04), and knee flexion impulse (KFI) (ΔR 2  = 0.23, pΔ = 0.02) were associated with thicker MC cartilage. A larger knee adduction angle (ΔR 2  = 0.20, pΔ = 0.03) and knee adduction moment (KAM) (ΔR 2  = 0.20, pΔ = 0.03) were associated with thinner MC thickness. Larger KFE (ΔR 2  = 0.20, pΔ = 0.03) was associated with thicker LC cartilage. Gait biomechanics were not associated with IC cartilage thickness. After accounting for co-variates, the combination of KFI and KAM was predictive of MC thickness (ΔR 2  = 0.37, pΔ = 0.01; Total R 2  = 0.52, p = 0.02). Meniscal injury, KAM, and KFI were significant predictors in the model. In the contralateral limb, KFE was associated with thicker MC cartilage (ΔR 2  = 0.16, pΔ = 0.05)., Significance: Sagittal and frontal plane knee mechanics during gait are uniquely associated with ultrasonographic measurements of femoral cartilage thickness in individuals with ACLR. Furthermore, concomitant medial meniscal injury was associated with thinner MC cartilage., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Immersion in chest-deep water may augment explicit memory in healthy adults however, there is limited information on how this environment might affect implicit memory or motor learning. The purpose of this study was to compare the speed and accuracy for learning a motor skill on land and in chest-deep water. Verbal word recall and grip strength were included to gain a more complete understanding of the intervention. Sixty-two younger adults (age = 23.3 ± 3.59 yrs.) were randomly assigned to either a water group immersed to the xiphoid or a land group. Participants in both groups completed the same eight practice trials of a mirror-drawing task on two separate days. Outcome measures for this task included time and error numbers to complete each drawing. The number of words recalled using a 12 word recall test, and peak grip strength using a hand dynamometer were measured each day of testing. The influence of environment and repeated practice on each outcome measure were assessed with an analysis of variance and effect sizes (ES). Time and errors for both groups significantly decreased with practice (p < 0.01, ES = 0.11-0.28), however the drawing time was greater in water than on land for trials 1, 5, and 6 (ES = 0.50-0.55). There was a 7% increase in words recalled (9.24 ± 1.19 vs 8.60 ± 1.19) and a 16% increase in grip strength (405 ± 104 vs 342 ± 83) for water than land groups (ES 0.54-0.64). Healthy adults in chest-deep water and on land display comparable mirror-drawing speed and accuracy after minimal practice. Curiously, water immersion may augment verbal word recall and grip strength abilities., Competing Interests: The authors have declared that no competing interests exist.

Objective: To examine the effect of whole-body vibration (WBV) on running biomechanics in individuals with anterior cruciate ligament reconstruction (ACLR)., Design: Single-blind randomized crossover trial., Setting: Research laboratory., Participants: Individuals (N=20) with unilateral ACLR (age [± SD]=22.3 [±3.3] years; mass=71.8 [±15.3] kg; time since ACLR=44.9 [±22.8] months; 15 females, 10 patellar tendon autograft, 7 hamstrings autograft, 3 allograft; International Knee Documentation Committee Score=83.5 [±9.3])., Main Outcome Measure: Participants performed isometric squats while being exposed to WBV or no vibration (control). WBV and control conditions were delivered in a randomized order during separate visits separated by 1-week washout periods. Running biomechanics of the injured and uninjured limbs were evaluated before and immediately after each intervention. Dependent variables included peak vertical ground reaction force (GRF) and loading rate (LR), peak knee flexion angle and external moment, and knee flexion excursion during the stance phase of running., Results: There was an increase in knee flexion excursion (+4.1°, 95% confidence interval [CI]: 0.65, 7.5°) and a trend toward a reduction in instantaneous LR after WBV in the injured limb (-4.03 BW/sec -1 , 95% CI -0.38, -7.69). No effect was observed on peak GRF, peak knee flexion angle, or peak external knee flexion moment, and no effect was observed in the uninjured limb., Conclusions: Our findings indicate that a single session of WBV acutely increases knee flexion excursion. WBV could be useful to improve running characteristics in individuals with knee pathology., (Copyright © 2018 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.)

Purpose: Individuals with anterior cruciate ligament reconstruction (ACLR) are at greater risk for knee osteoarthritis, partially because of chronic quadriceps dysfunction. Articular cartilage is commonly assessed using magnetic resonance imaging and radiography, but these methods are expensive and lack portability. Ultrasound imaging may provide a cost-effective and portable alternative for imaging the femoral cartilage. The purpose of this study was to compare ultrasonography of the femoral cartilage between the injured and uninjured limbs of individuals with unilateral ACLR, and to examine the association between quadriceps function and ultrasonographic measures of femoral cartilage., Methods: Bilateral femoral cartilage thickness and quadriceps function were assessed in 44 individuals with unilateral ACLR. Quadriceps function was assessed using peak isometric strength, and early (RTD100) and late (RTD200) rate of torque development., Results: Cartilage thickness at the medial femoral condyle (P < 0.001) and femoral cartilage cross-sectional area (P = 0.007) were smaller in the injured compared with the uninjured limb. After accounting for time since ACLR, quadriceps peak isometric strength was associated with cartilage thickness at the medial femoral condyle (r = 0.35, P = 0.02) and femoral cartilage cross-sectional area (r = 0.28, P = 0.04). RTD100 and RTD200 were not associated with femoral cartilage thickness or cross-sectional area., Conclusions: Individuals with ACLR have thinner cartilage in their injured limb compared with uninjured limb, and cartilage thickness is associated with quadriceps function. These results indicate that ultrasonography may be useful for monitoring cartilage health and osteoarthritis progression after ACLR.

Background: Obesity is considered a risk factor for knee osteoarthritis (OA) in part due to its influence on gait biomechanics. The heel strike transient (HST) is a characteristic of the ground reaction force that is indicative of a high rate of loading, but has not been evaluated in obese adults., Objective: To compare the incidence of HST in obese compared to normal weight adults., Methods: 15 normal-weight (males=7, age=20.4±2.1years, body mass index=21.6±1.3kg/m(2)) and 15 obese (males=7, age=21.2±1.9years, body mass index=33.5±4.3kg/m(2)) young adults completed 10 walking trials at a standardized speed and 10 trials at a self-selected speed while ground reaction force data were sampled. HST incidence was evaluated using a dichotomous method previously identified in the literature, and compared between groups using χ(2) analyses., Results: The number of individuals classified as possessing the HST differed between the obese and normal-weight groups (8/15 vs. 3/15, p=0.047). Evaluation of the standardized residuals indicated a significantly greater than expected incidence of the HST in the obese group when walking at a standardized speed., Conclusion: Our findings indicate that a greater proportion of obese compared to normal weight participants displayed a HST. The HST may provide a dichotomous method for identifying individuals with aberrant gait biomechanics., (Copyright © 2016 Elsevier B.V. All rights reserved.)