Pectoralis major and pectoralis minor are important muscles in the muscle group around the shoulder joint. Tightening and shortening these two muscles may have some influence on the movement of shoulder joint, but their specific influence on the flexion limitation of shoulder joint needs to be judged according to specific cases.

Studies have shown that the tension and shortening of pectoralis major and pectoralis minor may affect the flexion and flexion range of shoulder joint, but in most other cases it will not lead to the limitation of shoulder joint flexion. Shoulder flexion limitation is related to many factors, such as rotator cuff injury, muscle imbalance around shoulder joint and abnormal joint structure.

There are abundant data about the influence of muscles on shoulder joint movement and related research, so you can consult relevant textbooks or magazines. It is suggested that you can consult the following textbooks or relevant chapters in related magazines:

1. Handbook of Exercise Physiology, 2nd edition, by William J. Kramer and Steven J. Flack.

2. Human Exercise Anatomy: Shoulder and Upper Limb Muscles, 2nd Edition, by Nigel Palastanga and Derek Field.

3. Journal of Plastic Surgery. Sports physical therapy.

It should be noted that the problem of limited flexion of shoulder joint should be diagnosed and treated by consulting a professional doctor.