Maximal Strength Training for Breast Cancer Patients Undergoing Adjuvant Treatment

Abstract

Background: Breast cancer (BC) patients lose muscle strength during adjuvant treatment, thus affecting physical functioning. Maximal strength training (MST), with an emphasis on velocity in the concentric phase, improves maximal strength and walking efficiency. However, the effect of MST for BC patients undergoing treatment remains elusive. Aim: The aim of this study was to examine the feasibility and effects of such training in BC patients during clinical treatment on maximal muscle strength and functional performance. Methods: Thirty patients (46 ± 9 yr) with stage I-III BC were randomized to training group (TG) or control group (CG). TG performed MST twice a week for 3 months and CG followed prescribed BC treatment without strength training. TG performed four sets of four repetitions (4×4) of dynamic leg press with an emphasis on the maximal mobilization of force in the concentric action and with a progressively adjusted intensity corresponding to 85%–90% of one repetition maximum (1RM). Results: After the MST period, TG displayed significant 25 ± 7 kg (23%) increase in leg press 1RM ( P = 0.001). The strength improvements led to a significant increase in 6 minute walk distance (8%), 30-second chair test (23%), stair climb test (17%), and to a significant increase in walking performance of (8%) measured on an incremental treadmill test to exhaustion. In 3 months' posttest CG displayed significant 10 ± 8 kg (9%) decrease in 1RM ( P = 0.006). Reduced muscle strength leg to a significant decrease in 6 minute walk distance (6%), 30-second chair test (14%), stair climb test by (8%), and walking performance reduced significantly by (17%). Significant changes from pre to 3 months' posttest were observed between TG and CG in all functional performance measured variables. Conclusion: Maximal strength training was feasible during treatment and increased maximal muscle strength in BC patients. Increased strength led to improved functional performance after 24 training sessions each lasting only 20 min. Our results suggest that application of MST could accompany clinical training as a part of the treatment of BC patients. This training form showed excellent improvements in physical function tests and, thus should be implemented as a part of the breast cancer rehabilitation programs.