Establishing minimal clinically important difference for effectiveness of corrective exercises on craniovertebral and shoulder angles among students with forward head posture: a clinical trial study

BACKGROUND: Previous studies have addressed the effects of different exercises and modalities on forward head posture (FHP), but the minimal clinically important difference (MCID) of the effect of exercises on FHP remains unclear. Therefore, this study aimed to investigate the effects of selective corrective exercises (SCEs) on the craniovertebral angle (CVA) and shoulder angle (SA) in students with FHP and to establish MCID for these angles. METHODS: In this randomized clinical trial study, a total of 103 second-grade male students with FHP were enrolled. Participants were randomly assigned to experimental and control groups. CVA and SA of participants were measured before and after the 8-week selective corrective exercise program (including strengthening and stretching exercises). The photogrammetric method was used to measure CVA and SA. MCID value was calculated for CVA and SA using the distribution method. RESULTS: The results showed that there was a significant difference between the experimental and control groups in terms of CVA (F = 89.04, P = 0.005, Effect size = 0.47) and SA (F = 18.83, P = 0.005, Effect size = 0.16). After eight weeks of selective corrective exercises, the MCID values of CVA and SA were 1.40° and 1.34°, respectively. CONCLUSION: This study revealed that the selective corrective exercises might lead to postural correction of students having FHP problem. Results further indicated that a corrective exercise program would be considered beneficial if it increased CVA and SA values at least 1.40 and 1.34 degrees, respectively. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12887-022-03300-7.