Shoulder and Scapular Muscle Activity During Low and High Plank Variations With Different Body-Weight-Bearing Statuses

Abstract

Can, EN, Harput, G, and Turgut, E. Shoulder and scapular muscle activity during low and high plank variations with different body-weight-bearing statuses. J Strength Cond Res XX(X): 000–000, 2023—This study investigated the activation levels and activation ratios of shoulder and scapular muscles during low plank (LP) and high plank (HP) variations, with varying levels of body-mass support, including 4-point, 3-pod, and 2-point body-weight-bearing (BWB) statuses. The study was conducted with 21 healthy men (mean ± SD, 26 ± 6.5 years of age and 24.4 ± 2.4 kg·m−2 BMI). Ten different plank exercises were performed in a mixed order by changing elbow joint positions (LP and HP) and BWB statuses (2-point, 3-pod, and 4-point). Activation levels of the lower trapezius (LT), middle trapezius (MT), upper trapezius (UT), biceps brachii, triceps brachii, infraspinatus, and serratus anterior (SA) muscles were assessed with a surface electromyography device. Results of this study showed that elbow position changes resulted in higher LT (p = 0.01) and TB (p = 0.001) activation in HP exercises. In general, it was observed that an increase in BWB status was effective in increasing activation for the scapula and shoulder girdle muscles. The ratios of the UT muscle to the SA, LT, and MT muscles were less than 1 during side plank, bird dog, front reach, shoulder taps, and plank with shoulder external rotation exercises. High plank with toe touch exercise resulted in a marked increase in the UT activation. Therefore, it was concluded plank variations alter activation levels and activation ratios of shoulder and scapular muscles. Plank exercises may be used in shoulder rehabilitation and the progression in plank variations can be achieved by changing elbow position and BWB status based on individual requirements.

Validity of self-screening with the KOJI AWARENES™ test for range of motion and strength in healthy subjects

“…In the position used for KOJI AWARENESS TM scoring, the activity of the serratus anterior muscles, which act on scalene protraction, and the abdominal muscle group, which stabilizes the trunk against gravity, is important [26]. In particular, the closer the trunk approaches the horizontal and the longer the lever arm, the greater the activity of the serratus anterior and abdominal muscle groups required to maintain posture [30]. The KOJI AWARENESS TM score for “upper extremity stability and strength” reflects the function of the shoulder abductor and trunk flexor muscles to some extent.…”