Effect of Hand Position On Posterior Shoulder Muscle During Rear-Delt Machine Flys
Which hand grip is best for building the posterior shoulder muscles?
We’ve got an old but good one for you today, folks.
This study investigated the effect of hand position on muscle activation during the machine reverse fly exercise, a popular movement for strengthening the posterior shoulder muscles.
PMID: 23302754
Key Points
The study compared pronated (palms down) vs. neutral (thumbs up) hand positions during the reverse fly exercise.
19 resistance-trained men participated in the study.
The muscle activity of the posterior, middle, and infraspinatus muscles was measured using surface electromyography (EMG).
Aim and Methods
The researchers aimed to determine which hand position most effectively targets the posterior deltoid during the reverse fly exercise. Participants performed the exercise to muscular failure using both hand positions, with the order counterbalanced between subjects. The load used was approximately 75% of body weight.
Results
The neutral hand position resulted in significantly greater mean EMG activity for the posterior deltoid compared to the pronated position (p = 0.046).
The infraspinatus also showed significantly greater mean EMG activity in the neutral position compared to pronated (p = 0.002).
There were no significant differences in middle deltoid activation between the two hand positions.
