Research Review: Scapular Kinematics and Shoulder Elevation in a Traditional Push Up
By Nicholas Rolnick SPT, MS, CSCS
Edited by Brent Brookbush DPT, PT, COMT, MS, PES, CES, CSCS, ACSM H/FS
Original Citation: Suprak DN, Bohannon J, Morales G, et al. (2013). Scapular kinematics and shoulder elevation in a traditional push-up. Journal of Athletic Training. 48(6): 826-835. ARTICLE
Axis of rotation for each of the scapular movements investigated in the study. A. External Rotation B. Upward Rotation C. Posterior Tilting
Source: Suprak et al. 2013
Why is this relevant?: In healthy individuals without shoulder girdle pathology, the scapulae exhibit a characteristic pattern of upward rotation, posterior tilting, and external rotation as the arm is elevated. In the injured shoulder, scapular kinematics are altered, further predisposing the shoulder to degenerative and inflammatory pathologies such as rotator cuff tendinopathies and subacromial impingement syndromes (1). Push-ups are a commonly utilized exercise for strengthening and rehabilitating injured shoulders in an effort to restore optimal scapular movement. Previous studies have examined activity and recruitment of the rotator cuff muscles, the axioscapular muscles, and axiohumeral muscles during a push-up, without quantifying scapular kinematics (2-5). The current study filled a gap in the literature by investigating scapular kinematics during 3 variations of a push-up.
| Study Design | Cross-sectional Study |
| Level of Evidence | Level 2 |
| Subject Demographics |
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| Outcome Measures | Mean scapular rotations (posterior tilt, upward rotation, external rotation) was collected with respect to the thorax for every 5° increment across 105°-35° concentric elbow extension range of motion of the push-up |
| Results |
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| Conclusions | Scapular kinematics are influenced by shoulder abduction and elbow positioning during a push-up. Scapular PT was greater in self-selected and at-side conditions in comparison to shoulders abducted condition. Scapular UR was greater in the beginning of the range of motion (~105° - 85°) of elbow extension, during the shoulders abducted push-up, when compared to self-selected and at-side conditions. Scapular UR was greater in the middle of the range of motion (~75°-55°) of elbow extension, during the elbows at-side push-up condition when compared to the shoulders abducted and self-selected conditions. Scapular ER was greater in the self-selected and at-side conditions when compared to the shoulders abducted Push-up. |
| Conclusions of the Researchers | In healthy individuals, performing a push-up starting at 90° of shoulder abduction, may predispose individuals to shoulder pathology due to the inability to increase upward rotation and posterior tilting and a decrease in subacromial space. Push-ups should be performed at about 60° shoulder abduction, as demonstrated in images A or B below. |
Experimental Set-Up of the Pushup Test Positions. A. Self-selected throughout the range of motion. B. Arms adducted at the side throughout the range of motion. C. Arms elevated to 90 degrees throughout the range of motion. Source: Suprak et al. 2013
Review & Commentary:
Rehabilitation exercises in individuals with shoulder dysfunction should emphasize lower upper trapezius to higher serratus anterior and lower trapezius muscle activation ratios in an effort to enhance movement and positioning of the scapula during functional tasks (6-8). Push-ups and its exercise variants (knee push-ups, push-ups with a plus, suspension push-ups, etc.) are commonly prescribed in the clinical and fitness settings in an effort to increase strength, muscular performance, and facilitate neuromuscular re-education. Muscles targeted in the push-up include pectoralis major , triceps brachii, trapezius , biceps brachii, serratus anterior , rectus abdominis , internal and external obliques , and the rotator cuff (2-5). Previous studies on push-ups have investigated muscle activation during various hand placements (narrow vs. wide; internally rotated vs. neutral vs. externally rotated), bases of support (stable vs. unstable vs. oscillating), height of the feet (level vs. elevated), and tempo (fast vs. slow), but none have determined how scapular kinematics are influenced by shoulder abduction angle (2-5). The current study filled the gap in the literature by determining scapular kinematics in three different conditions where shoulder abduction varied. Of particular interest to the authors was the shoulders abducted to 90° (SE) condition, which was modeled after "traditional" push-up form (see image below), where the arm is perpendicular to the body. The authors hypothesized that during this condition the scapula would exhibit greater upward rotation (UR), posterior tilting (PT), and external rotation (ER) when compared to self-selected and arms at side (AAS) conditions, as evidenced by the previous literature on open-chain scapular kinematics (6).
This way to perform a pushup increases the likelihood of impinging the structures underneath the acromion. These include the biceps brachii tendon, supraspinatus tendon, subacromial bursa, and the coraco-acromial ligament. From www.stack.com
However, the results of this study suggest scapular kinematics during open-chain humeral abduction are not predictive of close-chain movement patterns of the shoulder and shoulder girdle. In particular, the authors noted increased humeral abduction during a push-up resulted in less posterior tilting of the scapula. The authors compared their results to a study performed by Decker and colleagues' (1999) on serratus anterior activity during a modified push-up (7). The authors of the current study posited that due to the increased weight-bearing and shoulder abduction seen in the traditional push-up (shoulders abducted condition), the serratus anterior cannot counter the increased activity of the upper trapezius. This results in an increase in relative anterior tipping. Other potential factors that may contribute to this finding include, increased passive tension of the pectoralis minor ( an anterior tipper of the scapula), and/or increased activity of the pectoralis major contributing directly to tipping, or indirectly via reciprocal inhibition of scapular posterior tippers. The opposite of these factors may contribute to the increase in external rotation of the scapula in the arms at side, and self-selected abduction angle conditions - as upward rotation of the scapula decreases, so does activity of the upper trapezius .
As expected, the amount of upward rotation of the scapula during the concentric phase of the push-up was correlated with initial position, with the arms-by-sides condition resulting in the least upward rotation and the arms abducted position resulting in the most. It is interesting to note that the arms-by-side condition exhibited greater initial upward rotation at the beginning of the concentric phase, potentially as a result of increased serratus anterior activity (although this is only speculation). Decreased external rotation was correlated with increased elbow extension in all of the conditions and was an expected result, as scapular protraction occurs during the concentric phase of a push-up.
The current study exhibited methodological strengths including the experimental protocol and data collection procedures. In order to establish statistical significance between group mean values of scapular posterior tilting, upward rotation and external rotation among the different conditions, an a priori power analysis was performed using an effect size of 0.53 (moderate effect size) to conclude that 15 participants were needed to indicate significance at the 0.05 level. A total of 16 participants were included in the study. The experimental protocol was described appropriately along with pictures and detailed descriptions of how the kinematic data was collected and interpreted. Inclusion and exclusion criteria were adequate and sufficiently described. Data collection for each participant was randomized to prevent an ordering bias.
There were a couple of limitations to the current study that should be acknowledged before findings are applied to practice. Although the data collection methodology was strong, the authors chose not to use a metronome to standardize concentric push-up duration and instead allowed the participants to use a manual count. While this may seem insignificant, one study showed that serratus anterior activation differed significantly with changes in push-up tempo, which could influence scapular positioning and kinematics during the concentric portion of the range of motion (4). Last, the current study examined healthy individuals without shoulder dysfunction and pain. It has been shown that scapular kinematics are altered in individuals who exhibit shoulder dysfunction; application of the results of this study to a population with shoulder pain should be done with caution (6,9). In future research, it may be interesting to compare the muscle activity of individuals with and without shoulder pain, at varying humeral elevations, to note how pain influences kinematics of the scapula and its associated musculature during a push-up.
Why is this study important?
The current study is the first of its kind to investigate how shoulder abduction influences scapular kinematics during the concentric phase of a push-up in pain-free individuals. The results of this study inspire considerations of the complex relationship between upper trapezius and serratus anterior in stabilization and positioning of the scapula.
In the optimal selection of therapeutic intervention for individuals with shoulder pathologies, a lower upper trapezius to a higher serratus anterior and lower trapezius muscle activation ratio is desired, along with an increase in posterior tilting, upward rotation, and external rotation of the scapula during arm elevation. This is hypothesized to maintain optimal subacromial space and scapular position. The results of the current study suggest that as shoulder abduction increases during a push-up, posterior tilting and external rotation of the scapula decrease.
How does it affect practice?
The push-up is is one of the few closed-chain exercises for the upper extremity commonly used in rehabilitation, fitness and performance facilities. However, before publication of this study not much was known about the relationship between beginning shoulder abduction position and its affect on scapular kinematics. The current study supports the notion that the traditional push-up, performed at 90° of shoulder abduction, may result in scapular kinematics that decreases subacromial space (increased anterior tipping and internal rotation) and place stress on subacromial structures. Rehabilitation and fitness professionals may consider using a shoulder abduction angle of less than 60° to optimize scapular motion.
How does it relate to Brookbush Institute Content?
This study supports the use of the "relative flexibility" progression for pushing motions described in the article Chest/Pushing Progressions . In individuals with Upper Body Dysfunction (UBD) , push-ups may be performed with hands at the shoulder-width position while maintaining humeral abduction angles less than 60º to reduce the chance of reinforcing faulty movement patterns and increasing stress on subacromial tissues. As corrective interventions are implemented to resolve UBD, abduction angles may increase and additional planes of motion added to enhance strength in various functional and sporting activities. Instruction and progressions for the push-up are shown below.
Brookbush Institute videos
Push-ups and Progressions
Suspension Push-ups
Power Push-ups
Weight Transfer Push-ups
© 2015 Brent Brookbush
Questions, comments, and criticisms are welcomed and encouraged
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- Lawrence RL, Braman JP, Laprade RF, Ludewig PM. (2014) Comparison of 3-dimensional shoulder complex kinematics in individuals with and without shoulder pain, part 1: sternoclavicular, acromioclavicular, and scapulothoracic joints. 44(9): 636-645.