Function, strength, and muscle activation of the shoulder complex in Crossfit practitioners with and without pain: a cross-sectional observational study

Abstract

Background The shoulder joint is the most commonly injured joint in CrossFit practitioners, because of the high intensity and loads associated with this sport. Despite the large number of clinical cases, there is a shortage of studies that investigate influence of biomechanical aspects of upper limbs' injuries on CrossFit practitioners. This study hypothesized that there would be a difference in function, strength, and muscle activation between Crossfit practitioners with and without shoulder pain. Methods We divided 79 Crossfit practitioners into two groups according to whether they reported pain (n = 29) or no pain (n = 50) in the shoulder during Crossfit training. Muscle function, strength, and activation were assessed using the Disability Arm, Shoulder and Hand function questionnaire, Upper Quarter Y Balance Test and Closed Kinetic Chain Upper Extremity Stability Test shoulder tests, isometric muscle strength assessment by manual dynamometry and muscle activation by surface electromyography and pain report. Results The function based on questionnaire was associated with pain (p = 0.004). We observed a statistically significant difference between the two groups only in the surface electromyography activity of the lower trapezius, and in the variables of shoulder pain and function (p = 0.038). Conclusion Crossfit practitioners with shoulder pain occurring during training showed good function and stability of the shoulder joint, but there was a reduction in the activation of stabilizing muscles, especially the lower trapezius. Trial registration Registro Brasileiro de Ensaios Clinico (Brasilian National Registry) with the ID: RBR-2gycyv.

Comparisons of Shoulder Muscle Activity and Muscle Activity Ratio during Serratus Anterior Exercise between CrossFit Practitioners with/without Shoulder Impingement Syndrome

“…This result can be attributed to the nature of CrossFit, which involves high-intensity training and various movements that heavily engage the serratus anterior muscle, such as overhead movements and push-ups. 25,26 During CrossFit exercises, the serratus anterior muscle plays a crucial role in scapulothoracic joint stability, humerus rotation control, and dynamic stability of the rotator cuff. 9,27 As a result, the serratus anterior muscle activity did not decrease in the group with impingement syndrome during CrossFit exercises, which involve intense training and numerous overhead movements that activate the serratus anterior.…”

“…The pain group exhibited lower trapezius muscle activity compared to the pain-free group. 26 Both the lower trapezius and serratus anterior muscles play critical roles in scapular upward rotation during initial and mid-range shoulder abduction. 28 The lower trapezius muscle's contribution to scapular upward rotation becomes significant as the scapular rotation axis approaches the shoulder acromion during arm elevation at 60-120 degrees.…”

Upper extremities functional disability and pain intensity in female volleyball athletes: cross-sectional study

“…Studies in the sports context showed that in master athletes with and without rotator cuff lesions, the greater the shoulder pain, the worse the shoulder function 16 . On the other hand, in Crossfit athletes with and without shoulder pain, upper limb function was inversely associated to pain 17 . Finally, preliminary evidence indicates an as-sociation between shoulder pain and functional disability with the shorter pectoralis minor muscle length in women swimmers, which may influence scapular kinematics 18 .…”

Skilled reaching test for shoulder function assessment in a rat model of rotator cuff tear: a pilot study

“…A study reported that 12.8% of individuals in their 50 s had RC tears, while the prevalence increased to 25.6% among those in their 60 s [ 1 ]. Among individuals with RC tears, approximately 34.6% may experience shoulder pain and dysfunction [ 1 – 4 ]. Consequently, patients commonly seek interventions aimed at alleviating pain and restoring shoulder function.…”