Publications by authors named "Masahide Yagi"

Objective: To examine the correlations amongst center of pressure (COP) trajectories, foot morphology, and knee symptoms in older women with medial knee deformity.

Design: This was a cross-sectional study.

Setting: Participants were recruited from 2 local orthopedic clinics.

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Background: This study aimed to clarify whether the anterior hip capsular ligament is impinged between the acetabulum and femur during hip flexion or adduction and to determine the difference in the distance between the femur and capsular ligament in healthy adults and those with hip pain.

Methods: Magnetic resonance imaging of the hip joint was conducted at the following hip positions: 0° of flexion, 60° of flexion, maximal flexion, and maximal flexion with adduction. A three-dimensional model of the capsular ligament and femur was constructed.

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Background: This study explored useful indices of potential fall risk in healthy older adults based on comprehensive clinical and simple quantitative posturographic measurements.

Methods: A total of 64 community-dwelling older adults aged ≥65 years were classified into fallers and non-fallers based on previous fall history. After excluding two participants due to missing data, 16 and 46 participants were included in the faller and non-faller groups, respectively.

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To investigate the effects of intentionally minimizing spinal motion and abdominal muscle contractions on intervertebral angles during quadruped upper and lower extremity lift (QULEL). Fifteen healthy men performed the QULEL under four conditions: without any special instructions (basic), with the intention to minimize spinal motion (intentional), with abdominal bracing (bracing), and with abdominal hollowing (hollowing). Each intervertebral angle was calculated from the local coordinate system using the marker data obtained from a motion capture system.

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Although evidence suggests that intramuscular fat infiltration may influence muscle strength, the precise mechanisms remain unclear. This study aimed to determine whether intramuscular fat infiltration affects muscle mechanical properties during contraction and whether these mechanical properties mediate the relationship between intramuscular fat infiltration and muscle strength. Seventy-nine healthy older women aged 75.

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  • Patellofemoral pain (PFP) is a common knee injury in athletes, often recurring, with its cause linked to the position of the patella during knee extension.
  • The study examined the relationship between the position of the patella and the tension of various soft tissues around the knee in both patients with PFP and healthy individuals.
  • Findings revealed that increased tension in the vastus lateralis (VL) and iliotibial band (ITB) caused a more lateral patellar position during contraction, which could help inform strategies for preventing and treating PFP.
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  • Piriformis syndrome is linked to muscle spasms and shortening of the piriformis muscle (PM), and physical therapy often involves stretching this muscle.
  • This study measured the shear elastic modulus of the PM in 21 healthy young men using ultrasonic shear wave elastography at 12 different stretching positions.
  • The findings demonstrated that the most effective stretching position for the PM was in maximum external rotation combined with 110° hip flexion and 40° hip adduction.
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Background: Joint moment arm is a major element that determines joint torque. This study aimed to investigate factors associated with knee extensor and valgus moment arms of the patellar tendon in older individuals with and without knee osteoarthritis.

Methods: Thirty-six participants with knee osteoarthritis (mean age, 78.

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  • This study compared the acute cartilage response between women with early-mild knee osteoarthritis (OA) and healthy controls by measuring cartilage thickness and echo intensity before and after walking.
  • A total of 56 women aged 50 and older were classified as either having early-mild knee OA or being healthy based on their symptoms and Kellgren-Lawrence grades.
  • Results showed that after a 15-minute walk, the cartilage thickness in the tibiofemoral joint was significantly reduced in the OA group compared to controls, indicating that patients with early-mild OA experience greater cartilage deformation from physical activity.
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Purpose: Manual annotations for training deep learning models in auto-segmentation are time-intensive. This study introduces a hybrid representation-enhanced sampling strategy that integrates both density and diversity criteria within an uncertainty-based Bayesian active learning (BAL) framework to reduce annotation efforts by selecting the most informative training samples.

Methods: The experiments are performed on two lower extremity datasets of MRI and CT images, focusing on the segmentation of the femur, pelvis, sacrum, quadriceps femoris, hamstrings, adductors, sartorius, and iliopsoas, utilizing a U-net-based BAL framework.

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Objective: We aimed to investigate the muscle coordination differences between a control group and patients with mild and severe knee osteoarthritis (KOA) using muscle synergy analysis and determine whether muscle coordination was associated with symptoms of KOA.

Method: Fifty-three women with medial KOA and 19 control patients participated in the study. The gait analyses and muscle activity measurements of seven lower limb muscles were assessed using a motion capture system and electromyography.

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Purpose: This study aimed i) to investigate the mechanical, morphological, and compositional characteristics of the supraspinatus muscle after rotator cuff repair by using ultrasound shear wave elastography (SWE) and B-mode imaging, and ii) to determine whether the morphological or compositional characteristics are associated with the mechanical characteristic of the supraspinatus during contraction.

Methods: Using SWE and B-mode imaging, active and passive shear moduli, muscle thickness, and echo intensity of the supraspinatus were measured from the repaired and contralateral control shoulders of 22 patients with rotator cuff repair. The shear modulus, muscle thickness, and echo intensity were compared between the repaired and control shoulders.

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  • This study explores an alternative to the costly shear modulus for assessing muscle elongation through echo intensity, aiming for a non-invasive method to improve stretching techniques.
  • A sample of 16 healthy males was analyzed at various angles of ankle dorsiflexion and plantar-flexion using ultrasound shear wave elastography to measure both shear modulus and echo intensity.
  • The findings revealed a strong correlation between shear modulus and ankle angle, while echo intensity showed moderate correlations, suggesting that echo intensity may serve as a viable indicator for muscle elongation.
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Purpose: This study aimed to investigate the association of muscle thickness (MT) and echo intensity (EI) obtained at different regions along the muscle length with muscle volume (MV), intramuscular adipose tissue (IntraMAT), and muscle strength of the quadriceps femoris (QF).

Patients And Methods: A total of 135 community-dwelling adults (64 men and 71 women) participated in the study. Ultrasound scanning of the rectus femoris (RF) and vastus intermedius (VI) was performed at three locations (from mid- to distal thigh).

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Background: Muscle thickness (MT) and echo intensity (EI) measurements are ultrasound alternatives to magnetic resonance imaging (MRI) for evaluating muscle quantity and quality. The vastus medialis (VM) is a clinically important muscle, and assessment methods that most accurately reflect its quantity and quality are required. This study aimed to examine the correlation between MT and EI measured in the supine and sitting postures with corresponding MRI-measured muscle quantity and quality indices.

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Rotator cuff tear is a common shoulder injury that causes shoulder dysfunction and pain. Although surgical repair is the primary treatment for rotator cuff tear, it is well recognized that impaired force exertion of muscles connecting to the involved tendon and subsequent complemental change in the force exertion of synergist muscles persist even after repair. This study aimed to identify the compensation strategy of shoulder abductors by examining how synergist muscles respond to supraspinatus (SSP) muscle force deficit in patients with rotator cuff repair.

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Objective: The purposes of our study were to (1) identify muscle function-based clinical phenotypes in patients with hip osteoarthritis (OA) and (2) determine the association between those phenotypes and radiographic progression of hip OA.

Design: Prospective cohort study.

Setting: Clinical biomechanics laboratory of a university.

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Purpose: We aimed to determine whether altered cartilage echo intensity is associated with knee osteoarthritis (OA) severity and whether the alteration occurs before thinning of the femoral cartilage in knee OA.

Methods: The medial femoral cartilage thickness and echo intensity of 118 women aged ≥ 50 years were assessed using an ultrasound imaging device. Based on the Kellgren-Lawrence (KL) grade and knee symptoms, participants were classified into five groups: control (asymptomatic grades 0-1), early OA (symptomatic grade 1), grade 2, grade 3, and grade 4.

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Background: The characteristics of muscle degeneration in individual quadriceps in early knee osteoarthritis (OA) and the association of muscle quantity and quality on knee dysfunction remain unclear. This study aimed to clarify the characteristics of muscle degeneration in individual quadriceps muscles in early knee OA and elucidate the association of muscle volume and intramuscular adipose tissue (intraMAT) with knee dysfunction, including functional disabilities, symptoms, and joint morphology.

Methods: Fifty participants were categorized into early knee OA and healthy control groups.

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Background: Patellar malalignment is a risk factor of patellofemoral pain. Evaluation of the patellar alignment have mostly used magnetic resonance imaging (MRI). Ultrasound (US) is a non-invasive instrument that can quickly evaluate patellar alignment.

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Purpose: This study aimed to examine the effect of age on the mechanical properties, muscle size, and muscle quality in the upper and lower limb and trunk muscles.

Methods: We evaluated the shear modulus (G), muscle thickness (MT), and echo intensity (EI) of the upper and lower limb and trunk muscles of 83 healthy women (21-83-year-old). The G values of some limb muscles were measured in relaxed and stretched positions.

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Article Synopsis
  • Patients with knee osteoarthritis (KOA) experience muscle quality loss, indicated by increased echo intensity (EI) in their vastus medialis (VM) muscles and a higher extracellular water-to-intracellular water (ECW/ICW) ratio in the thigh.
  • This study followed 33 KOA patients over 3 years to analyze how muscle degeneration relates to functional disabilities and symptoms, categorizing participants into progressive and non-progressive groups based on changes in their knee scoring system (KSS) scores.
  • Findings revealed that a higher baseline VM-EI significantly predicted worsening functional disabilities (OR 1.24) and symptoms (OR 1.13), suggesting that ultrasonography of VM-EI can be
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Objective: Hallux valgus, flatfoot, and rearfoot eversion are well-known major complications of knee osteoarthritis (OA). However, there is no consensus on the association between these foot malalignments and knee symptoms or function. Thus, this study aimed to examine the association between foot alignment and knee symptoms or function in patients with knee OA.

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Synopsis of recent research by authors named "Masahide Yagi"

  • - Recent research by Masahide Yagi has focused on understanding the biomechanical and physiological factors affecting muscle function and joint health in older adults, particularly regarding conditions like knee osteoarthritis and rotator cuff injuries.
  • - Key findings include the influence of intramuscular fat infiltration on muscle mechanics during contraction, the importance of muscle coordination in gait among patients with knee osteoarthritis, and novel imaging techniques like ultrasonography and shear wave elastography to assess muscle and cartilage properties.
  • - Yagi's studies emphasize the relationship between muscle quality, fat infiltration, and functional disabilities, offering insights into potential therapeutic interventions and rehabilitation strategies for aging populations and those with musculoskeletal problems.