Breast reconstruction is an important step and option after mastectomy and can help improve the quality of life of breast cancer patients. Therefore, the proportion of patients undergoing breast reconstruction in conjunction with mastectomy is steadily increasing. Despite recent advances in less invasive techniques, postoperative movement restrictions are unavoidable, and these postoperative pain or functional limitations can last for months to years. Patients most often experience a decrease in shoulder function, which negatively impacts their physical function and is an important factor in their ability to perform activities of daily living. Early postoperative exercise has been proven to have positive results in promoting the recovery of shoulder function in breast cancer patient. However, there is a lack of research on the effectiveness of early postoperative exercise in the context of breast reconstruction. Therefore, this study aims to evaluate the effect of early postoperative exercise on patients' shoulder and trunk function after breast reconstruction.

Inclusion Criteria:

1. Adult women between the ages of 19 and 70
2. Pathologically diagnosed with breast cancer
3. Scheduled to undergo unilateral or bilateral mastectomy and breast reconstruction

Exclusion Criteria:

1. Adult women age 70 and order who have been diagnosed with breast cancer
2. Had surgery or radiation therapy to the same side of the armpit
3. Scheduled to undergo or have undergone delyed breast reconstruction
4. Have breast cancer that has spread to other cancers or is metastatic
5. Deemed by the healthcare provider to have unmeasurable postoperative complications (seroma, laceration, lymphedema observed within 1 month of surgery)
6. Have problems reading or understanding Korean or have problems communicating with the researcher
7. Have difficulty exercising as judged by the healthcare provider