Purpose <p>The purpose of this study was to compare the strength, length of selected muscles, and range of motion (ROM) of the upper quarter between people with and without upper crossed syndrome (UCS).</p> Methods <p>In this case–control study, 62 healthy females aged 30 to 42 were selected and equally divided into two groups, 31 people in the group of people with UCS and 31 people in the group of people without UCS, Forward head angle, rounded shoulder angle, kyphosis angle, strength, length of selected muscles and ROM of the upper quarter were measured in both groups. Data analysis was done with SPSS software version 26. Independent t and U-Mann–Whitney statistical tests were used to compare the variables at a significant (<i>p</i> &lt; 0.05) level.</p> Results <p>This study's findings are significant, revealing a clear distinction in the strength (<i>p</i> = 0.001), length (<i>p</i> = 0.001) of the selected muscles, and ROM of the upper quarter (<i>p</i> = 0.001) between individuals with and without UCS.</p> Conclusion <p>People with UCS differ from those without UCS in terms of muscle strength, length, and ROM. These results provide valuable insights into the impact of UCS on musculoskeletal health.</p>