Humeral retroversion, shoulder range of motion, and functional mobility in striking martial arts athletes

The aim of the study was to evaluate humeral retroversion, shoulder range of motion, and functional mobility in karatekas, boxers, kickboxers, and mixed martial arts fighters. This study investigated adaptive alterations in striking martial arts. Forty young healthy participants took part in the study. 20 people who professionally trained in boxing, kickboxing, karate, and Mixed Martial Arts (MMA) fighters (age: 23.5 ± 7.1, age of participation 11.8 ± 3.65, sports experience 9.55 ± 5.13, body weight 79.2 ± 13 kg, BMI 24.4 ± 3.3) were qualified for the group of athletes. 20 people (age: 27 ± 5.5, body weight 79.4 ± 7.4, BMI 24.5 ± 1.2) were included in the control group, who had no previous experience with striking combat sports. An ultrasound device and a digital inclinometer were used for the examination of the humeral retroversion angle. The mobility of the shoulder was also tested using the Functional Movement Screen (FMS). There was a significant (p < 0.001, r = 0.92) asymmetry between the dominant and non-dominant limb in the humeral retroversion angle in the athlete group. A statistically significant moderate correlation (p < 0.05) was found between the value of the retroversion angle and the range of motion of passive and active internal rotation, and external rotation, and the shoulder mobility in the FMS test. However, there were no statistically significant differences (p > 0.05) in the humeral retroversion angles between groups. The striking martial arts athletes do not exhibit significant differences in humeral retroversion compared to non-athletes, however they display notable asymmetry between limbs, with higher values in the non-dominant arm. Additionally, the observed correlation between humeral retroversion and shoulder rotation range of motion highlights the potential impact of humeral retroversion on upper limb performance and injury risk.