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Affiliation |
Engineering educational research section Mechanical Intelligence Engineering Program |
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Title |
Associate Professor |
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External Link |
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YAMAKO Go
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Degree 【 display / non-display 】
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Doctor (Engineering) ( 2007.3 Niigata University )
Research Areas 【 display / non-display 】
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Life Science / Biomedical engineering
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Manufacturing Technology (Mechanical Engineering, Electrical and Electronic Engineering, Chemical Engineering) / Design engineering
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Manufacturing Technology (Mechanical Engineering, Electrical and Electronic Engineering, Chemical Engineering) / Mechanics of materials and materials
Papers 【 display / non-display 】
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Biomechanical effect of metal augment and bone graft on cup stability for acetabular reconstruction of total hip arthroplasty in hip dysplasia: a finite element analysis Reviewed International coauthorship
Wang Y, Wang M, Li C, Nakamura Y, Deng L, Yamako G, Chosa E, Pan C.
BMC Musculoskeletal Disorders 23 ( 1 ) 277 2022.3
Language：English Publishing type：Research paper (scientific journal) Publisher：BMC Musculoskeletal Disorders
Background: Different methods of acetabular reconstruction with total hip arthroplasty (THA) for Crowe II and III of adult developmental dysplasia of the hip (DDH) acetabular bone defect have been implemented clinically. However, the biomechanical effect of different augmented materials for acetabular reconstruction in THA on shell stability has never been discussed. Methods: In the present study, autologous bone graft (BG)and metal (Ti6Al4V) augment (MA) were simulated with several acetabular bone defect models of DDH in THA. The contact pressure and micromotion between the shell and host bone were measured for evaluating the shell stability using a finite element method. Results: The peak contact stress between shell and host bone was higher in the MA situation (12.45 vs 8.71 MPa). And the load transfer path was different, for BG models, the high local contact stresses were found at the junction of bone graft and host bone while for MA models the concentrated contact stresses were at the surface of MA. The peak relative micromotion between shell and host bone was higher in the MA situation (12.61 vs 11.13 µm). However, the peak micromotion decreased in the contact interface of MA and cup compared to the BG models. Conclusions: The higher micromotion was found in MA models, however, enough for bone ingrowth, and direct stronger fixation was achieved in the MA-cup interface. Thus, we recommended the MA can be used as an option, even for Crowe III, however, the decision should be made from clinical follow-up results.
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Wang Y, Yamako G, Okada T, Arakawa H, Nakamura Y, Chosa E
Journal of orthopaedic surgery and research 16 ( 1 ) 465 2021.7
Authorship：Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：Journal of Orthopaedic Surgery and Research
Background: Intertrochanteric curved varus osteotomy (CVO) has been widely used to remove the necrotic bone away from the weight-bearing portion in the treatment of osteonecrosis of the femoral head (ONFH). However, whether all types of necrosis will benefit from CVO, in terms of the stress level, the effect of different center-edge (CE) angles of acetabulum on stress distribution of necrosis after CVO, and the relationship between the intact ratio and the stress of necrosis, has never been addressed. The purpose of the study was to evaluate the influence of CVO on the stress reduction in necrotic bone using a finite element analysis (FEA) with different CE angles. Methods: CVO finite element models of the hip joint were simulated with a lesion of 60°. The osteotomy angles were divided into four configurations (15°, 20°, 25°, and 30°), and three types (A, B, and C1) of lesions were established based on the Japanese Investigation Committee (JIC) classification. In addition, two CE angles (18° and 33°) of acetabulum were considered. The maximum and mean von Mises stress were analyzed in terms of the necrotic bone by a physiological loading condition. Moreover, the correlation of the intact ratio measured in 3D and the stress distribution after CVO was analyzed. Results: Stress reduction was obtained after CVO. For type B, the CVO angle was 20° (0.61 MPa), and for type C1, the CVO angle was 30° (0.77 MPa), if the mean stress level was close to type A (0.61 MPa), as a standard. The maximum and mean von Mises stress were higher in the CE angle of 18°models, respectively. The intact ratio measured in 3D had a good negative correlation with stress after CVO and had more influence on stress distribution in comparison to other geometric parameters. Conclusions: For making decisions about the biomechanics of CVO, a CVO angle of > 20° was recommended for type B and > 30° was safe for type C1. The risk of progressive collapse was increased in the insufficient situation of the weight-bearing portion after CVO. The intact ratio could provide information about clinical outcomes and stress distribution after CVO.
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A hand-worn inertial measurement unit for detection of bat–ball impact during baseball hitting Reviewed
Punchihewa N.G., Arakawa H., Chosa E., Yamako G.
Sensors 21 ( 9 ) 2021.5
Authorship：Last author, Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：Sensors
Swinging a baseball bat at a pitched ball takes less than half of a second. A hitter uses his lower extremities to generate power, and coordination of the swing motion gradually transfers power through the trunk to the upper extremities during bat–ball impact. The most important instant of the baseball swing is at the bat–ball impact, after which the direction, speed, height, and distance of the hit ball determines whether runs can be scored. Thus, analyzing the biomechanical parameters at the bat–ball impact is useful for evaluating player performance. Different motion-capture systems use different methods to identify bat–ball impact. However, the level of accuracy to detect bat–ball impact is not well documented. The study aim was to examine the required accuracy to detect bat–ball impact timing. The results revealed that ±2 ms accuracy is required to report trunk and hand kinematics, especially for higher-order time-derivatives. Here, we propose a new method using a hand-worn inertial measurement unit to accurately detect bat–ball impact timing. The results of this study will be beneficial for analyzing the kinematics of baseball hitting under real-game conditions.
DOI： 10.3390/s21093002
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Shadow pitching deviates ball release position: kinematic analysis in high school baseball pitchers Reviewed
Miyazaki S., Yamako G., Totoribe K., Sekimoto T., Kadowaki Y., Tsuruta K., Chosa E.
BMC Sports Science, Medicine and Rehabilitation 13 ( 1 ) 26 2021.3
Language：English Publishing type：Research paper (scientific journal) Publisher：BMC Sports Science, Medicine and Rehabilitation
Background: Although shadow pitching, commonly called “towel drill,” is recommended to improve the throwing motion for the rehabilitation of pitching disorders before the initiation of a throwing program aimed at returning to throwing using a ball, the motion differs from that of normal throwing. Learning improper motion during ball release (BR) may increase shoulder joint forces. Abnormal throwing biomechanics leads to injures. However, there has been no study of shadow pitching focusing on the BR position. The purpose of the present study was to evaluate the BR position and kinematic differences between shadow pitching and normal throwing. In addition, the effect of setting a target guide for BR position on throwing motion was examined in shadow pitching. Methods: The participants included in this study were 20 healthy male students who were overhand right-handed pitchers with no pain induced by a throwing motion. Participants performed normal throwing (task 1), shadow pitching using a hand towel (task 2), and shadow pitching by setting a target of the BR position (task 3). A motion capture system was used to evaluate kinematic differences in throwing motions, respectively. Examination items comprised joint angles and the differences in BR position. Results: BR position of task 2 shifted significantly toward the anterior, leftward, and downward directions compared with task 1. The distance of BR position between tasks 1 and 2 was 24 ± 10%. However, task 3 had decreased BR deviation compared with task 2 (the distance between 3 and 1 was 14 ± 7%). Kinematic differences were observed among groups at BR. For shoulder joint, task 2 showed the highest value in abduction and horizontal adduction among groups. In spine flexion, left rotation and thorax flexion, task 2 was significantly higher than task 1. Task 3 showed small differences compared with task 1. Conclusions: The BR position of shadow pitching deviated significantly in the anterior, leftward, and downward directions compared with normal throwing. Furthermore, we demonstrated that the setting of BR target reduces this deviation. Thus, the target of BR position should be set accurately during shadow pitching exercises in the process of rehabilitation.
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Non-anatomical placement adversely affects the functional performance of the meniscal implant: a finite element study. Reviewed International coauthorship
Shriram D, Yamako G, Kumar GP, Chosa E, Cui F, Subburaj K
Biomechanics and modeling in mechanobiology 20 ( 3 ) 1167 - 1185 2021.3
Language：English Publishing type：Research paper (scientific journal) Publisher：Biomechanics and Modeling in Mechanobiology
Non-anatomical placement may occur during the surgical implantation of the meniscal implant, and its influence on the resulting biomechanics of the knee joint has not been systematically studied. The purpose of this study was to evaluate the biomechanical effects of non-anatomical placement of the meniscal implant on the knee joint during a complete walking cycle. Three-dimensional finite element (FE) analyses of the knee joint were performed, based on the model developed from magnetic resonance images and the loading conditions derived from the gait pattern of a healthy male subject, for the following physiological conditions: (i) knee joint with intact native meniscus, (ii) medial meniscectomized knee joint, (iii) knee joint with anatomically placed meniscal implant, and (iv) knee joint with the meniscal implant placed in four different in vitro determined non-anatomical locations. While the native menisci were modeled using the nonlinear hyperelastic Holzapfel–Gasser–Ogden (HGO) constitutive model, the meniscal implant was modeled using the isotropic hyperelastic neo-Hookean model. Placement of the meniscal implant in the non-anatomical lateral-posterior and lateral-anterior locations significantly increased the peak contact pressure in the medial compartment. Placement of the meniscal implant in non-anatomical locations significantly altered the tibial rotational kinematics and increased the total force acting at the meniscal horns. Results suggest that placement of the meniscal implant in non-anatomical locations may restrain its ability to be chondroprotective and may initiate or accelerate cartilage degeneration. In conclusion, clinicians should endeavor to place the implant as closest as possible to the anatomical location to restore the normal knee biomechanics.
Books 【 display / non-display 】
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関節外科（特集 運動器を扱うメディカルスタッフのためのバイオメカニクス必携）
企画・編集：帖佐 悦男（ Role： Joint author）
メジカルビュー社 2016.11
Responsible for pages：94-99 Language：Japanese Book type：Scholarly book
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未来型人工関節を目指して －その歴史から将来展望まで―
吉川秀樹, 他（ Role： Joint author , pp.181-186）
日本医学館 2013.7
Language：Japanese Book type：Scholarly book
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整形・災害外科 （特集 骨・関節のバイオメカニクス –最近の進歩）
企画：黒坂昌弘（ Role： Joint author , pp.1365-1374）
金原出版 2012.10
Language：Japanese Book type：Scholarly book
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橈骨遠位端骨折 最近の進歩と治療法の選択
斎藤英彦，他（ Role： Joint author , pp.168-172）
金原出版 2010.7
Language：Japanese Book type：Scholarly book
MISC 【 display / non-display 】
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Punchihewa N.G., Miyazaki S., Chosa E., Yamako G.
Sensors (Switzerland) 20 ( 24 ) 1 - 11 2020.12
Language：Japanese Publishing type：Rapid communication, short report, research note, etc. (scientific journal) Publisher：Sensors (Switzerland)
Baseball hitting is a highly dynamic activity, and advanced methods are required to accurately obtain biomechanical data. Inertial measurement units (IMUs) can capture the motion of body segments at high sampling rates both indoor and outdoor. The bat rotates around the longitudinal axis of the body; thus, trunk motion plays a key role in baseball hitting. Segmental coordination is important in transferring power to a moving ball and, therefore, useful in evaluating swing kinematics. The current study aimed to investigate the validity and reliability of IMUs with a sampling rate of 1000 Hz attached on the pelvis, thorax, and hand in assessing trunk and hand motion during baseball hitting. Results obtained using the IMU and optical motion capture system (OMCS) were compared. Angular displacements of the trunk segments and spine joint had a root mean square error of <5◦ . The mean absolute error of the angular velocities was ≤5%. The intra-class correlation coefficient (>0.950) had excellent reliability for trunk kinematics along the longitudinal-axis. Hand velocities at peak and impact corresponded to the values determined using the OMCS. In conclusion, IMUs with high sampling rates are effective in evaluating trunk and hand movement coordination during hitting motion.
DOI： 10.3390/s20247331
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ロコモ度の機器による評価は? (特集 ロコモをめぐる最近の話題) -- (クリニカルクエスチョン)
帖佐 悦男, 鄧 鋼, 田村 宏樹, 山子 剛, 塩満 智子, 鶴田 来美
Loco cure = ロコキュア : 運動器領域の医学情報誌 2 ( 4 ) 340 - 343 2016.11
Language：Japanese Publishing type：Article, review, commentary, editorial, etc. (trade magazine, newspaper, online media) Publisher：先端医学社
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Pathological Analysis of Adaptive Sports and Study of Device Development : Focused on Biomechanics
37 35 - 42 2016.6
Language：Japanese Publishing type：Article, review, commentary, editorial, etc. (scientific journal)
Presentations 【 display / non-display 】
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楽しみながら「ロコモ」を予防する「LOCOBOT」の開発と社会実装について Invited
山子剛
みやざき新産業創出研究会 医療福祉技術分科会
Event date： 2022.3.16
Presentation type：Public lecture, seminar, tutorial, course, or other speech
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テーパーウェッジ型人工股関節ステムにおける術後大腿骨の骨密度予測
松枝賢伸，和佐宗樹，帖佐悦男，山子剛
日本機械学会九州支部大75期総会講演会
Event date： 2022.3.9
Language：Japanese Presentation type：Oral presentation (general)
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アクションカメラを用いたカヤック用動作分析システムの開発
木村遼，NIROSHAN Punchihewa，川口翼，宮崎茂明，帖佐悦男，山子剛
日本機械学会九州支部大75期総会講演会
Event date： 2022.3.9
Language：Japanese Presentation type：Oral presentation (general)
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半月板損傷後に用いる非吸収性インプラントの軟骨保護効果
内山大輔，ISURU Udayanga，帖佐悦男，山子剛
日本機械学会九州支部大75期総会講演会
Event date： 2022.3.9
Language：Japanese Presentation type：Oral presentation (general)
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フォースプレートを用いた立ち上がり動作解析によるロコモティブシンドロームの評価とロコモ年齢 Invited
山子剛, Niroshan G. Punchihewa, Deng Gang, 鳥取部光司, 荒川英樹, 帖佐悦男
第48回日本臨床バイオメカニクス学会 2021.11.5
Event date： 2021.11.5 - 2021.11.6
Language：Japanese Presentation type：Symposium, workshop panel (nominated)
Awards 【 display / non-display 】
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第9回”ヘルスケア産業づくり”貢献大賞「特別賞」
2022.6 九州ヘルスケア産業推進協議会(HAMIQ)
山子 剛
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第48回日本臨床バイオメカニクス学会感謝状
2021.11 日本臨床バイオメカニクス学会
山子 剛
Award type：Award from Japanese society, conference, symposium, etc. Country：Japan
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Best Paper Award
2019.3 The 7th IIAE International Conference on Industrial Application Engineering
Geunho Lee, Yuki Fujio, Go Yamako, Hiroki Tamura, Etsuo Chosa
Award type：Award from international society, conference, symposium, etc. Country：Japan
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Outstanding Contribution in Reviewing (Medical Engineering & Physics)
2015.1 ELSEVIER
Go Yamako
Award type：Honored in official journal of a scientific society, scientific journal Country：Japan
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日本整形外科基礎学術集会感謝状
2014.10 日本整形外科基礎学術集会
山子 剛
Award type：Award from Japanese society, conference, symposium, etc. Country：Japan
Grant-in-Aid for Scientific Research 【 display / non-display 】
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半月板損傷後の膝軟骨を守るFloat-ring型インプラントの開発
Grant number：22H03925 2022.04 - 2026.03
科研費 基盤研究(B)
Authorship：Principal investigator
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人工股関節全置換術後の生体力学的な未来予測
Grant number：17K01362 2017.04 - 2021.03
科研費 基盤研究(C)
Authorship：Principal investigator
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術後の骨量減少が生じない傾斜低弾性人工股関節ステムの最適化研究（国際共同研究強化）
Grant number：15KK0213 2016.04 - 2018.03
科研費 国際共同研究加速基金（国際共同研究強化）
Authorship：Principal investigator
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術後の骨量減少が生じない傾斜低弾性人工股関節ステムの最適化研究
Grant number：26750148 2014.04 - 2016.03
科研費 若手研究(B)
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皮質骨の微細孔構造及び基質の石灰化が骨力学特性に及ぼす影響
Grant number：20700378 2008.04 - 2010.03
科研費 若手研究(B)
Grant type：Competitive