Bent-over flyes: back or shoulders?

　　The bent over fly is a common exercise in fitness, but many people mainly focus on it. exercise There is doubt about back or shoulders. Below we analyze this action in detail from multiple aspects.

Movement characteristics and muscle involvement

　　Rear deltoid dominant: When leaning over to fly, the rear deltoid muscle is the main muscle group. In a leaning posture of 25-40 degrees, when performing horizontal abduction movements, the rear deltoid muscles will fully contract and play a leading role. For example, when the arms are opened from the front of the body to the sides, the posterior deltoid muscles will exert significant force.

　　latissimus dorsi synergy: The latissimus dorsi muscles also work together during the bent-over fly. While maintaining a neutral spine and retracted scapulae, the latissimus dorsi muscles will assist in stabilizing the body and assist in completing the movement to a certain extent. But it's not the main exercise goal.

Key points of movements affect exercise areas

　　Scapular stabilization: Keeping the scapula stable can ensure the stability and accuracy of the movement, allowing the posterior deltoid muscles to better exert force. If the scapula is unstable, it may cause the trapezius muscle to compensate and affect the training effect of the posterior deltoid muscle.

　　Slightly flexed elbow joint: Slightly flexing the elbow joint can reduce the pressure on the joint capsule, and at the same time help align the lines of force, allowing the posterior deltoid muscles to participate in the action more effectively and avoid elbow joint injuries.

Comparison with back training exercises

　　Differences in action trajectories: Compared with typical back training movements, the movement trajectory of the bent over fly is mainly horizontal abduction, while the back training movements are mostly vertical pull-down or pull-back. For example, pull-ups are a vertical upward movement that focus on exercising the erector spinae muscles of the back.

　　Muscle activation differs: Back training movements mainly activate back muscles such as latissimus dorsi and rhomboids, while bent-over flyes mainly activate shoulder muscles such as posterior deltoid and infraspinatus muscles. Myoelectric analysis also showed that the timing of muscle activation was different between the two.

Training arrangements and precautions

　　Small weight, more reps: In order to better stimulate the rear deltoid muscles, it is recommended to use a small weight for multiple reps of training. This can increase the metabolic stress on the muscles and promote muscle growth.

　　fatigue management: Reasonable scheduling of training cycles and fatigue management are important. Avoid risks such as tendinitis caused by overtraining and give your body enough recovery time.

　　In fitness training, it is crucial to clearly define the focus of each movement to achieve the desired training effect. The bent over fly is a classic movement, and the definition of its exercise parts has always been a topic of concern.