en فیزیوتراپی Physiotherapy مطالعه موردی Case Study <strong>Background and Objectives: T</strong>his study aims to determine the relationship between pain, muscle strength, function, and quality of life (QoL) in overhead players with chronic shoulder internal impingement syndrome.<br> <strong>Methods</strong>: Forty-seven overhead players consisting of 15 men, 32 and women (mean age 32.45&plusmn;7.2) with chronic shoulder internal impingement were enrolled. The pain was measured by a visual analogue scale (VAS). Disabilities of the arm, shoulder, and hand&nbsp;(DASH) and shoulder pain and disability index (SPADI) questionnaires were used to measure pain and function, and a short form (SF)-36 questionnaire to measure QoL. Muscle strengths were evaluated in both hands with a hand-held dynamometer and players were asked to hold the maximal voluntary isometric contraction (MVIC) in the middle range for 3 s and rest for 30 s between each test and each contraction was repeated three times on both affected and healthy side and the average of contractions was considered for each side.&nbsp;<br> <strong>Results</strong>: The study showed a significant relationship between pain, the strength of shoulder muscle groups (-0.354), function (-0.935), and QoL (-0.861) in overhead throwers with chronic shoulder internal impingement syndrome and the strength of internal rotators of the affected shoulder decreased more than others. (P<0.05)<br> &nbsp;<strong>Conclusions</strong>: This correlational study showed a significant relationship between pain and strength of shoulder muscles and function and QoL in overhead throwers with this syndrome.<br> &nbsp; Pain, Strength, Function, Shoulder internal impingement syndrome 0 0 http://fdj.iums.ac.ir/browse.php?a_code=A-10-298-1&slc_lang=en&sid=1 Seyedeh Pardis Emadi Pardisemadi1202@gmail.com 10031947532846003346 0009-0006-9240-2294 No Department of Physiotherapy, School of Rehabilitation, Iran University of Medical Sciences, Tehran, Iran. Soheil Mansour Sohani Sohani.soheil@gmail.com 10031947532846003347 10031947532846003347 Yes Department of Physiotherapy, School of Rehabilitation, Iran University of Medical Sciences, Tehran, Iran. Reza Salehi salehi200@yahoo.com 10031947532846003348 10031947532846003348 No Department of Physiotherapy, School of Rehabilitation, Iran University of Medical Sciences, Tehran, Iran. Mohammad Taghipour Darzi taghipourm@yahoo.com 10031947532846003349 10031947532846003349 No Department of Physiotherapy, School of Rehabilitation, Babol University of Medical Sciences, Babol, Iran.