Effects of circuit training on muscle strength, cardiovascular fitness, and quality of life in women diagnosed with primary breast cancer

Breast cancer is the most prevalent type of cancer in New Zealand women. As the number of women surviving breast cancer increases, the resultant implications for the health system make research into the physical and psychological effects of breast cancer and its treatment a priority. Due to other competing factors, physical activity is often sidelined during primary care or breast cancer education. Breast cancer literature has reported that exercise reduces many of the debilitating side effects often associated with breast cancer. However, despite the research, breast cancer survivors often experience declines in exercise participation. Furthermore, there appears to be a lack of exercise information available to breast cancer survivors. Significant positive effects of regular exercise on a wide range of outcomes have emerged including, aerobic capacity, muscular strength, body composition, fatigue and quality of life. Although research has focused on either aerobic or resistance training, new research is emerging on the benefits of a combined exercise programme within this population. Circuit resistance training (CRT) offers a potential mechanism through which aerobic and resistance exercise can be effectively combined to target multiple parameters concurrently. Therefore, the aim of this study is to evaluate the effects of a CRT programme over 20 weeks on aerobic capacity, muscular strength, body composition, and quality of life on women diagnosed with primary breast cancer. Twelve survivors of breast cancer, who all completed treatment for an average of 16.2 months, participated in a 20 week study which prescribed two 45 minute circuit sessions per week. Participants were their own controls and comparisons of results from baseline to final measure. Significant improvements in upper body strength as tested through a one-repetition maximum chest press (25.9 ± 3.7 vs. 35.9 ± 5.2kg; p0.05) or body composition measures of weight, skeletal muscle mass, fat mass and body fat percentage (p>0.05). In conclusion, the CRT programme produced significant improvements in muscular strength on the upper and lower body, and various dimensions of quality of life among breast cancer survivors. The results from the CRT demonstrate that circuit training is well tolerated among breast cancer survivors, with no incidence of adverse effects directly attributable to the study