Feasibility and Potential Effects of Exercise Training Combining Eccentric and Concentric Cycling in Patients With Breast Cancer

Breast cancer treatment impairs aerobic and neuromuscular capacities, leading to a decrease in quality of life. Exercise may counteract these effects if it is individualized to patient characteristics. This study aimed to assess the feasibility and potential effects of combined concentric and eccentric cycling training on exercise capacity. Twenty-one patients with breast cancer (59 ± 9 years; 164 ± 5 cm; and 72 ± 13 kg) were assessed before and after exercise training twice a week for six weeks. Assessments included a test to determine power output at ventilatory threshold (P_VT), a 6-min walking test (6-MWT), and a measure of quadriceps muscle force and architecture. Exercise training adherence, attendance and rate of perceived exertion (RPE) were also measured. The exercise training included two concentric cycling bouts (7 × 1 min at 130%P_VT and 5 × 2 min at 110%P_VT) and one eccentric cycling bout (7 × 1 min at 130%P_VT). The exercise training protocol was associated with high attendance (90%) and adherence (98%) rates and was well tolerated (3.5/10 of RPE). From pre- to postexercise training, we documented an increase in aerobic capacity, characterized by increased oxygen consumption (+11.1% and p = 0.001) and power output (+10.9% and p = 0.004) at VT. These changes were accompanied by neuromuscular adaptations, with greater muscle force (+18.3% and p < 0.001), vastus lateralis thickness (+5.0% and p = 0.031), fascicle length (+11.9% and p < 0.001), pennation angle (+11.3% and p = 0.001), and rectus femoris cross-sectional area (+11.6% and p = 0.020). These adaptations led to increased 6-MWT distance (+4.4% and p = 0.005). Thanks to an individualized exercise training with high adherence and attendance, aerobic and neuromuscular parameters were improved, leading to greater exercise capacity in breast cancer.