Publications by authors named "Takayuki Muraki"

Article Synopsis
  • - The study aimed to analyze how different scapular muscle exercises affect scapular movement and muscle activity in healthy men.
  • - Researchers measured scapular motion using a motion capture system and muscle activity with surface electromyography, comparing results across five exercises.
  • - Findings suggest that the horizontal adducted elevation exercise is more effective for enhancing scapular upward rotation and serratus anterior muscle activity than the push-up plus exercise.
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  • The study examined foot function issues in 138 male baseball players, focusing on those with shoulder/elbow pain compared to those without.
  • Results showed that 27% of players had a history of shoulder/elbow pain, while 7% reported pain during the examination, indicating a significant relationship between injuries and foot function problems.
  • Specifically, impaired foot function was more prevalent on the non-throwing side (60%) and the throwing side (60%) of injured players compared to non-injured ones, highlighting the impact of throwing shoulder/elbow disabilities on foot health.
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Glenohumeral osteoarthritis (OA) is one of the most common causes of shoulder pain. Conservative treatment options include physical therapy, pharmacological therapy, and biological therapy. Patients with glenohumeral OA present shoulder pain and decreased shoulder range of motion (ROM).

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Background: Although tension on the supraspinatus tendon may be increased by wearing an abduction brace in an improper position or activities of daily living with the operated arm in the brace, the amount of tension has not been objectively evaluated.

Methods: Eighteen patients who underwent arthroscopic rotator cuff repair were enrolled. The stiffness of the repaired supraspinatus tendon was measured with ultrasound elastography to estimate the tension on the repaired tendon.

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  • The study aimed to identify physical risk factors for osteochondritis dissecans (OCD) of the humeral capitellum in young baseball players aged 8-14, investigating how certain physical characteristics may contribute to the condition.
  • Conducted over a year, the research involved assessments of shoulder and hip range of motion, and a total of 3651 players were followed up, revealing that 71 (1.9%) developed OCD.
  • The results indicated that a higher Rohrer index and reduced hip internal rotation range of motion on the nondominant side were significant risk factors associated with the development of OCD among these young athletes.
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  • * Out of 38 male goalkeepers, 16% were found to have a history of DTS, with notable differences in scapular positioning and rotator cuff strength compared to those without DTS.
  • * Findings suggest that issues like scapular malpositioning and limited scapular retraction may be linked to the occurrence of DTS in these athletes.
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Article Synopsis
  • - The study investigates how changes in soft-tissue structures affect shoulder function in baseball players, particularly focusing on the relationship between these changes and pathologic internal impingement.
  • - Involving 81 high-school baseball players, the research compares two groups: those with internal impingement and a control group, specifically analyzing humeral retroversion and ranges of motion in external and internal rotations.
  • - Findings reveal that the internal impingement group exhibited a significantly greater difference in soft-tissue-related external rotation compared to the control group, suggesting that soft-tissue changes are linked to internal impingement in throwing athletes.
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Background: Although rotator cuff repair is performed to restore the function of the rotator cuff muscles and glenohumeral (GH) joint motion, little has been known regarding the recovery process. The purpose of this study was (1) to investigate changes over time in activities of the supraspinatus and deltoid muscles assessed by ultrasound real-time tissue elastography (RTE) after rotator cuff repair and (2) to determine contributions of the activities of these muscles to the GH joint motion.

Methods: Twenty patients after rotator cuff repair and 13 control participants were enrolled in this study.

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Background: Altered scapular motion is thought to be one of the factors associated with the development of symptomatic rotator cuff tears. However, the differences in kinematics and muscle activities of scapular upward/downward rotation between patients with symptomatic and asymptomatic tears are unclear. The purpose of this study was to compare the differences in kinematics and muscle activities of scapular rotation among patients with symptomatic and asymptomatic tears, and healthy individuals.

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Background: Pitch velocity is associated with elbow injuries among skillful baseball players. However, the relationship between pitch velocity and throwing elbow injuries among youth players has not yet been clarified.

Purpose: To investigate the influence of pitch velocity on medial elbow pain and medial epicondyle abnormality among youth baseball players.

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Regulation of whole-body angular momentum (WBAM) is essential for maintaining dynamic balance during gait. Patients with hemiparesis frequently fall toward the anterior direction; however, whether this is due to impaired WBAM control in the sagittal plane during gait remains unknown. The present study aimed to investigate the differences in WBAM in the sagittal plane during gait between patients with hemiparesis and healthy individuals.

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Background: Throwing injuries to the shoulder joint often occur during shoulder external rotation. An appropriate combination of thoracic, scapular, and humeral motion during throwing is important to prevent such injuries, but it is unclear how thoracic posture contributes to shoulder motion during throwing.

Research Question: The purpose of this study, therefore, was to clarify the influence of thoracic posture on scapulothoracic and glenohumeral motion during shoulder external rotation.

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Background: The regulation of ankle joint stiffness by combination of activation of plantarflexor and dorsiflexor during gait has not been investigated in patients with hemiparesis. The objective of the present study was to examine the relationship between combination of activation of ankle muscles and quasi-joint stiffness (QJS) during the stance phase of gait.

Methods: The activation of the medial head of the gastrocnemius (MG), soleus, and tibialis anterior, gait parameters were collected from 19 patients with hemiparesis due to stroke and from 12 healthy controls using a three-dimensional motion analysis system.

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Backgrounds: There have been many reports describing that the capsular fibrosis of the shoulder joint is the main cause of frozen shoulder, whereas others reported the significance of subacromial impingement as an etiological factor. The purpose of this study was to investigate the contact pressure between the coracoacromial arch and the rotator cuff tendons to clarify the contact phenomenon in shoulders with joint contracture.

Methods: Fourteen fresh-frozen cadaveric shoulders were used.

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Background: How the use of the transosseous-equivalent (TOE) technique effects the stress concentration in repaired rotator cuff tendon is unknown. This study was conducted to determine the strain between the intact rotator cuff tendon and the tendon repaired using the TOE technique with and without medial row suture tying.

Materials And Methods: Strain of the infraspinatus tendon from 10 fresh-frozen cadavers was measured at the (A) tendon insertion, (B) tendon footprint, (C) tendon of the medial suture level, and (D) musculotendinous junction of the tendon.

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Background: Aging is a contributing factor to rotator cuff tears. Dysfunction of the scapular muscles can be a potential cause of rotator cuff tears. Although aging can contribute to dysfunction of the scapular muscles and subsequently result in rotator cuff tears, the effects of aging on scapular muscles are unclear.

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Background: The relationship between the disabled throwing shoulder and humeral retroversion has recently attracted a great deal of attention. However, none of the previous studies clarified when the side-to-side difference of humeral retroversion in young baseball players would start. This study aimed to clarify when the difference of humeral retroversion in the dominant and nondominant sides appeared in baseball players.

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Background: Patients with subacromial impingement were reported to show abnormal scapular positions during shoulder elevation. However, the relationship between the scapular positions and subacromial impingement is unclear. The purpose of this study was to biomechanically determine the effect of scapular position on subacromial contact behavior by using fresh frozen cadavers.

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Purpose: The aim of this study was to compare the stiffness of the dorsal scapular muscles before and after computer work between individuals with and without neck and shoulder complaints.

Methods: Thirty subjects were divided into patient (n = 18) and control (n = 12) groups. The stiffness of the upper trapezius, levator scapulae, and rhomboid major was measured using ultrasound elastography before and after a 30-min typing task.

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Purposes: It has been reported that the amount of posterior tilt and upward rotation in scapular motions decreases with aging. The purposes of the current study were to investigate age related scapular motion regression and scapular restriction in patients with idiopathic frozen shoulder (IFS).

Methods: The groups were recruited as follows: two groups of 50 asymptomatic subjects aged in their twenties and fifties, and 56 patients with IFS.

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Purpose: Vibro-acoustography is a new imaging technique based on the dynamic radiation force of ultrasound. The purpose of this study was to apply this new imaging technique to the diagnosis of small partial-thickness rotator cuff tears and to determine how small of tears could be detected with this imaging technique.

Methods: Seven supraspinatus tendons excised from embalmed cadavers were used.

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Background: Thickening of the medial ulnar collateral ligament in the throwing arm of adult baseball players is a well-known phenomenon. However, onset of the thickening is unclear among young baseball players. The purpose of this study was to evaluate the thickness of the medial ulnar collateral ligament in junior high and high school baseball players.

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The purpose of this study was to clarify whether the activity of the shoulder girdle muscles could be estimated by measuring the elasticity of these muscles under several levels of muscle contraction through ultrasound real-time tissue elastography (RTE). Ten healthy men performed submaximal voluntary contractions (MVC) in each manual muscle testing position for the middle deltoid, upper trapezius, supraspinatus, levator scapulae, and rhomboid major. The elasticity of these muscles was measured using ultrasound RTE during the task.

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It is unclear whether muscle contraction is necessary to increase quasi-joint stiffness (QJS) of the ankle joint during gait in patients with hemiparesis. The purpose of the present study was to investigate the relationship between QJS and muscle activation at the ankle joint in the stance phase during gait in patients with hemiparesis. Spatiotemporal and kinetic gait parameters and activation of the medial head of the gastrocnemius (MG), soleus (SOL), and tibialis anterior (TA) muscles were measured using a 3-dimensional motion analysis system and surface electromyography, in 21 patients with hemiparesis due to stroke and 10 healthy individuals.

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Background: Although elasticity of the supraspinatus muscle and tendon is a useful parameter to represent the conditions of the supraspinatus muscle and tendon, assessment of the elasticity in clinical settings has not been established. The purpose of this study was to determine the elasticity of the supraspinatus muscle belly and tendon under different muscle contraction conditions using ultrasound real-time tissue elastography (RTE).

Methods: Twenty-three healthy individuals participated in this study.

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