Women who have had axillary lymph nodes removed for the management of breast cancer are at increased risk of developing upper extremity lymphedema. Physical therapists, surgeons, and other health professionals have warned these women to avoid vigorous, repetitive, or excessive upper body exercise, believing that such types of exercise might actually induce lymphedema. The purpose of this series of case reports was to challenge that belief by systematically measuring the arm circumferences, across three points in time, of 20 women who had received axillary dissection and who were competing in the vigorous, upper body sport of Dragon Boat racing. Measurably different change was defined as an increase in circumference of the ipsilateral upper extremity at any of the four landmarks of >0.5 inches between Time 1 and Time 2 or between Time 1 and Time 3; only two women showed a measurably different change (5/8 in). Furthermore, none of the women showed a clinically significant difference in arm circumference between the ipsilateral and contralateral extremities at Time 3.