1.Comparison of Medial and Lateral Hamstring Muscle Activation and Strength across Three Resistance Directions during Isometric Knee Flexion in Healthy Participants: A Pilot Study
Jin Seong KIM ; Il Kyu AHN ; Kyu Sung CHUNG
The Korean Journal of Sports Medicine 2026;44(1):34-40
Purpose:
This study aimed to identify an effective hamstring exercise method that selectively activates the medial and lateral hamstrings.
Methods:
Five healthy adults were enrolled in this cross-sectional pilot laboratory study. Surface electromyography was recorded from the semitendinosus and biceps femoris of the dominant limb during prone isometric knee flexion at 90°, with resistance applied at 0° (neutral), 45° (resistance applied from lateral to medial), and −45° (resistance applied from medial to lateral) in randomized order. Three 5-second maximal trials per direction were performed with 30-second rest intervals. Isometric knee flexion strength was measured using a Smart KEMA system (Koreatech Co., Ltd.), and the outcomes were descriptively compared.
Results:
The participants (three females and two males; 32.4±4.5 years) demonstrated the highest mean semitendinosus and biceps femoris activity at 0° (154.7±24.1 μ V and 100.2±25.1 μ V, respectively) and the lowest at 45° (105.3±5.6 μ V and 76.9±4.4 μ V) and −45° (129.3±12.1 μ V and 64.7±19.0 μ V). The medial-to-lateral activity ratio was highest at −45° (2.2±0.6), compared with 0° (1.6±0.3) and 45° (1.4±0.1). Strength was the greatest at 0° (7.5±0.5) compared with 45° (6.4±1.3) and −45° (5.5±1.3).
Conclusion
In this pilot study, the medial-to-lateral electromyographic ratio tended to be highest when resistance was applied at −45°, suggesting greater medial hamstring recruitment under this condition. These descriptive findings are preliminary and should be confirmed in adequately powered studies. Modifying the direction of resistance may be a feasible strategy to bias medial (−45°) or lateral (45°) hamstring recruitment depending on rehabilitation goals.
2.Prognostic Comparison of Long-Term Outcomes and Nodal Recurrence for Persistent and Recurrent Differentiated Thyroid Cancer
Yung Jee KANG ; Ji-Hoon KIM ; Ji Ye LEE ; Sun Wook CHO ; Young Joo PARK ; Kyu-Eun LEE ; Su-Jin KIM ; Hanaro PARK ; Sung Joon PARK ; Soon-Hyun AHN ; Eun-Jae CHUNG
Clinical and Experimental Otorhinolaryngology 2026;19(2):185-193
Objectives:
. Differentiated thyroid cancer (DTC) has a favorable prognosis. However, indeterminate lymph nodes (LNs) are common, making it challenging to distinguish recurrent from persistent DTC. Previous studies have not specifically compared the prognosis between recurrent and persistent DTC. Therefore, we aimed to compare prognosis and oncologic characteristics between these two groups.
Methods:
. This retrospective cohort study was conducted at a single tertiary care institution and included 265 patients with DTC (recurrent, 109; persistent, 156) who underwent reoperation between November 1, 1999, and August 31, 2018, for structural disease. Patients with distant metastasis at the time of initial diagnosis were excluded. Clinical and oncological characteristics, patterns of LN metastasis, disease-free survival (DFS), and overall survival (OS) were compared between the two groups. For DFS, time zero was defined as the date of the second operation.
Results:
. Recurrent DTC had a higher incidence of central LN metastasis (P=0.003), infield recurrence (P<0.001), and distant metastasis (P<0.001). In contrast, persistent DTC more frequently exhibited lateral LN metastasis (P=0.003) and outfield recurrence (P<0.001). The most common site of neck LN metastasis was ipsilateral level VI/VII (51.4%) in recurrent DTC and ipsilateral level IV (43.0%) in persistent DTC. Ten-year DFS was significantly lower in recurrent DTC than in persistent DTC (41.0% vs. 67.9%; P<0.001). Recurrent DTC, older age, a higher number of metastatic LNs at the second operation (first reoperation), and R1/R2 resection at the second operation were associated with decreased DFS. OS did not significantly differ between recurrent and persistent DTC (P=0.160).
Conclusion
. Recurrent DTC is associated with poorer DFS than persistent DTC, although OS does not significantly differ between the two groups.
3.Process of developing basic veterinary clinical performance guidelines based on common clinical manifestations in Korea
Kichang LEE ; Heungshik S. LEE ; Yong Jun KIM ; Incheol PARK ; Kangmoon SEO ; Seong Mok JEONG ; Kyu-Woan CHO ; Jin Young CHUNG ; Dongbin LEE ; Chun-Sik BAE ; Sung-Lim LEE ; Ki-Jeong NA ; Sooyoung CHOI ; Inseong JEONG ; Pan Dong RYU ; Sang-Soep NAHM
Journal of Veterinary Science 2026;27(2):e24-
Objective:
To explain process of developing basic veterinary clinical performance guidelines, based on frequently observable clinical manifestations, thereby supporting competencybased veterinary education in Korea.
Methods:
A structured review of learning outcomes established by Korean Association of Veterinary Medical Colleges (KAVMC) was conducted by a planning committee including veterinary educators, practitioners, and advisory members. Owner-oriented descriptions were used to frame each performance task, and each was mapped to corresponding learning outcomes. These tasks were aligned with learning outcomes recommended by the KAVMC to support the development of communication, clinical reasoning, and performance-related competencies among veterinary students, thereby enhancing day-one clinical readiness.
Results:
In total, 63 clinical manifestations for a guidebook format that can be used for clinical education were identified and categorized by organ systems that are described in language understandable to animal owners.
Conclusions
and Relevance: The basic veterinary clinical performance guidelines based on common clinical manifestations would serve as a vital component in veterinary education to reinforce core graduation competencies.
4.Evaluating prostate cancer diagnostic methods:The role and relevance of digital rectal examination in modern era
Investigative and Clinical Urology 2025;66(3):181-187
This review examines diagnostic methods for prostate cancer, focusing on the role of digital rectal examination (DRE) alongside modern advancements like prostate-specific antigen (PSA) testing, Prostate Health Index (PHI), magnetic resonance imaging (MRI), and prostate-specific membrane antigen positron emission tomography (PSMA-PET), particularly in the context of Korea’s aging population and healthcare challenges. Technological advancements have significantly improved prostate cancer diagnosis. PSA testing, while widely used, suffers from low specificity, often resulting in unnecessary biopsies. PHI addresses PSA’s limitations, offering enhanced accuracy, particularly in the “gray zone” of PSA levels. MRI has revolutionized diagnostic precision, enabling detailed staging and targeted biopsies, but its cost and limited availability restrict widespread use. Emerging tools like PSMAPET and AI (artificial intelligence)-driven diagnostics promise further improvements but remain costly and complex, limiting their routine application. Despite these advancements, DRE continues to serve as an accessible and cost-effective tool, particularly in low-resource settings or where advanced diagnostics are unavailable. In Korea, where prostate cancer is often diagnosed at more aggressive stages, and universal health insurance emphasizes cost efficiency, DRE retains value as part of a multimodal approach.Concerns about DRE’s reproducibility and discomfort remain, but its utility in specific high-risk populations justifies its inclusion in diagnostic strategies. DRE, despite its limitations, remains a valuable tool in Korea’s prostate cancer diagnostic landscape, particularly within a comprehensive, cost-effective, and context-sensitive screening strategy.
6.Endoscopic vacuum therapy for gastrointestinal transmural defects: a literature review
Tan Minh LE ; Van Huy TRAN ; Kyu Sung CHUNG ; Seong Woo JEON
Clinical Endoscopy 2025;58(2):181-190
Endoscopic vacuum therapy (EVT) has emerged as a transformative approach for managing gastrointestinal (GI) transmural defects, offering a less invasive and more promising alternative to surgery. Initially developed to address anastomotic leaks after rectal surgery, the application of EVT has expanded to include other locations within the GI tract. This review investigated the principles, indications, procedures, outcomes, challenges, and future perspectives of EVT for the management of GI transmural defects. In conclusion, EVT has demonstrated favorable outcomes in GI defect closure, with reduced complications, shortened hospital stay, and decreased morbidity rates as compared with conventional treatments. Although EVT faces challenges in some specific anatomical locations and in managing severe complications such as major bleeding, ongoing advancements in technology and standardization efforts offer promise for broader indications and better outcomes. Future perspectives include exploring novel EVT devices, refining patient selection criteria and pre-emptive applications, and standardizing procedural protocols.
7.Study Protocol of Expanded Multicenter Prospective Cohort Study of Active Surveillance on Papillary Thyroid Microcarcinoma (MAeSTro-EXP)
Jae Hoon MOON ; Eun Kyung LEE ; Wonjae CHA ; Young Jun CHAI ; Sun Wook CHO ; June Young CHOI ; Sung Yong CHOI ; A Jung CHU ; Eun-Jae CHUNG ; Yul HWANGBO ; Woo-Jin JEONG ; Yuh-Seog JUNG ; Kyungsik KIM ; Min Joo KIM ; Su-jin KIM ; Woochul KIM ; Yoo Hyung KIM ; Chang Yoon LEE ; Ji Ye LEE ; Kyu Eun LEE ; Young Ki LEE ; Hunjong LIM ; Do Joon PARK ; Sue K. PARK ; Chang Hwan RYU ; Junsun RYU ; Jungirl SEOK ; Young Shin SONG ; Ka Hee YI ; Hyeong Won YU ; Eleanor WHITE ; Katerina MASTROCOSTAS ; Roderick J. CLIFTON-BLIGH ; Anthony GLOVER ; Matti L. GILD ; Ji-hoon KIM ; Young Joo PARK
Endocrinology and Metabolism 2025;40(2):236-246
Background:
Active surveillance (AS) has emerged as a viable management strategy for low-risk papillary thyroid microcarcinoma (PTMC), following pioneering trials at Kuma Hospital and the Cancer Institute Hospital in Japan. Numerous prospective cohort studies have since validated AS as a management option for low-risk PTMC, leading to its inclusion in thyroid cancer guidelines across various countries. From 2016 to 2020, the Multicenter Prospective Cohort Study of Active Surveillance on Papillary Thyroid Microcarcinoma (MAeSTro) enrolled 1,177 patients, providing comprehensive data on PTMC progression, sonographic predictors of progression, quality of life, surgical outcomes, and cost-effectiveness when comparing AS to immediate surgery. The second phase of MAeSTro (MAeSTro-EXP) expands AS to low-risk papillary thyroid carcinoma (PTC) tumors larger than 1 cm, driven by the hypothesis that overall risk assessment outweighs absolute tumor size in surgical decision-making.
Methods:
This protocol aims to address whether limiting AS to tumors smaller than 1 cm may result in unnecessary surgeries for low-risk PTCs detected during their rapid initial growth phase. By expanding the AS criteria to include tumors up to 1.5 cm, while simultaneously refining and standardizing the criteria for risk assessment and disease progression, we aim to minimize overtreatment and maintain rigorous monitoring to improve patient outcomes.
Conclusion
This study will contribute to optimizing AS guidelines and enhance our understanding of the natural course and appropriate management of low-risk PTCs. Additionally, MAeSTro-EXP involves a multinational collaboration between South Korea and Australia. This cross-country study aims to identify cultural and racial differences in the management of low-risk PTC, thereby enriching the global understanding of AS practices and their applicability across diverse populations.
10.Study Protocol of Expanded Multicenter Prospective Cohort Study of Active Surveillance on Papillary Thyroid Microcarcinoma (MAeSTro-EXP)
Jae Hoon MOON ; Eun Kyung LEE ; Wonjae CHA ; Young Jun CHAI ; Sun Wook CHO ; June Young CHOI ; Sung Yong CHOI ; A Jung CHU ; Eun-Jae CHUNG ; Yul HWANGBO ; Woo-Jin JEONG ; Yuh-Seog JUNG ; Kyungsik KIM ; Min Joo KIM ; Su-jin KIM ; Woochul KIM ; Yoo Hyung KIM ; Chang Yoon LEE ; Ji Ye LEE ; Kyu Eun LEE ; Young Ki LEE ; Hunjong LIM ; Do Joon PARK ; Sue K. PARK ; Chang Hwan RYU ; Junsun RYU ; Jungirl SEOK ; Young Shin SONG ; Ka Hee YI ; Hyeong Won YU ; Eleanor WHITE ; Katerina MASTROCOSTAS ; Roderick J. CLIFTON-BLIGH ; Anthony GLOVER ; Matti L. GILD ; Ji-hoon KIM ; Young Joo PARK
Endocrinology and Metabolism 2025;40(2):236-246
Background:
Active surveillance (AS) has emerged as a viable management strategy for low-risk papillary thyroid microcarcinoma (PTMC), following pioneering trials at Kuma Hospital and the Cancer Institute Hospital in Japan. Numerous prospective cohort studies have since validated AS as a management option for low-risk PTMC, leading to its inclusion in thyroid cancer guidelines across various countries. From 2016 to 2020, the Multicenter Prospective Cohort Study of Active Surveillance on Papillary Thyroid Microcarcinoma (MAeSTro) enrolled 1,177 patients, providing comprehensive data on PTMC progression, sonographic predictors of progression, quality of life, surgical outcomes, and cost-effectiveness when comparing AS to immediate surgery. The second phase of MAeSTro (MAeSTro-EXP) expands AS to low-risk papillary thyroid carcinoma (PTC) tumors larger than 1 cm, driven by the hypothesis that overall risk assessment outweighs absolute tumor size in surgical decision-making.
Methods:
This protocol aims to address whether limiting AS to tumors smaller than 1 cm may result in unnecessary surgeries for low-risk PTCs detected during their rapid initial growth phase. By expanding the AS criteria to include tumors up to 1.5 cm, while simultaneously refining and standardizing the criteria for risk assessment and disease progression, we aim to minimize overtreatment and maintain rigorous monitoring to improve patient outcomes.
Conclusion
This study will contribute to optimizing AS guidelines and enhance our understanding of the natural course and appropriate management of low-risk PTCs. Additionally, MAeSTro-EXP involves a multinational collaboration between South Korea and Australia. This cross-country study aims to identify cultural and racial differences in the management of low-risk PTC, thereby enriching the global understanding of AS practices and their applicability across diverse populations.

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