Previous studies have reported that deep neck flexor (DNF) exercise can improve neck problems, including neck pain, forward head posture, and headache, by targeting the deep and superficial muscles of the neck. Despite the prevailing opinion across studies, the benefits of DNF can vary according to the type of neck problems and the outcome measures adopted, ranging from positive outcomes to non-significant benefits. A meta-analysis was conducted in this study to assess conclusive evidence of the impact of DNF exercise on individuals with neck problems. We used PUBMED, MEDLINE, NDSL, EMBASE, and Web of Science to search for primary studies and the key terms used in these searches were “forward head posture (FHP),” “biofeedback,” “pressure biofeedback unit,” “stabilizer,” “headache,” and “neck pain.” Twenty- four eligible studies were included in this meta-analysis and were coded according to the type of neck problems and outcome measures described, such as pain, endurance, involvement of neck muscle, craniovertebral angle (CVA), neck disability index (NDI), cervical range of motion (CROM), radiographs of the neck, posture, strength, endurance, and headache disability index. The overall effect size of the DNF exercise was 0.489. The effect sizes of the neck problems were 0.556 (neck pain), –1.278 (FHP), 0.176 (headache), and 1.850 (mix). The effect sizes of outcome measures were 1.045 (pain), 0.966 (endurance), 0.894 (deep neck flexor), 0.608 (superficial neck flexor), 0.487 (CVA), 0.409 (NDI), and 0.252 (CROM). According to the results of this study, DNF exercise can effectively reduce neck pain. Thus, DNF exercise is highly recommend as an effective exercise method for individuals suffering from neck pain.

INTRODUCTION
MATERIALS AND METHODS
    1. 문헌 검색
    2. 논문 선정 기준
    3. 논문 선정
    4. 논문의 질
    5. 자료 분석과 코딩
    6. 효과 크기 분석
    7. 출판 오류
RESULTS
    1. 목 질환의 종류에 따른 효과 크기 분석
    2. 종속변수에 따른 효과 크기 분석
    3. 출판 오류
    4. 논문의 질 평가
DISCUSSION
REFERENCES

• 박주희(연세대학교 보건과학대학 물리치료학과) | Joo-Hee Park (Department of Physical Therapy, College of Health Science, Yonsei University)
• 전혜선(연세대학교 보건과학대학 물리치료학과/연세대학교 보건환경대학원 인간공학치료학과) | Hye-Seon Jeon (Department of Physical Therapy, College of Health Science, Yonsei University/Department of Ergonomic Therapy, The Graduate School of Health and Environment, Yonsei University) Corresponding Author
• 김지현(연세대학교 일반대학원 물리치료학과) | Ji-hyun Kim (Department of Physical Therapy, The Graduate School, Yonsei University)
• 김예진(연세대학교 일반대학원 물리치료학과) | Ye Jin Kim (Department of Physical Therapy, The Graduate School, Yonsei University)
• 문경아(연세대학교 일반대학원 물리치료학과) | Gyeong Ah Moon (Department of Physical Therapy, The Graduate School, Yonsei University)
• 임원빈(연세대학교 보건과학대학 물리치료학과) | One-bin Lim (Department of Physical Therapy, College of Health Science, Yonsei University)