Effects of Different Training Intensity Distributions on Endurance Capacity in Breast and Prostate Cancer Survivors: A Randomized Controlled Trial

This study aimed to compare the effects of isocaloric polarized and threshold training intensity distribution on endurance capacity in breast and prostate cancer survivors. A total of 28 breast and 27 prostate cancer survivors were randomly assigned to a polarized (POL, n = 27 (13 women), age 60 ± 8 years, peak oxygen uptake (VO_2peak) 23 mL·min^-1 kg^-1), or threshold training group (ThT, n = 28 (15 women), age 59 ± 10 years, VO_2peak 23 mL·min^-1 kg^-1) who completed two sessions per week on a cycle ergometer over 12 weeks. Exercise duration was adapted to obtain equivalent energy expenditure in both groups. Cardiopulmonary exercise and verification tests were performed to determine endurance capacity (VO_2peak, peak power output (PPO), ventilatory threshold (VT₁), blood lactate thresholds (LT₁ and IAT)), and maximal exhaustion. POL did not achieve the planned polarized intensity distribution and rather performed a pyramidal training. Pyramidal and threshold training significantly (p < 0.001) improved endurance capacity regarding VO_2peak (0.09 and 0.12 L·min^-1), PPO (27 and 17W), power output at VT₁ (11 and 13W), oxygen uptake at VT₁ (0.09 and 0.11 L·min^-1), power output at LT₁ (7 and 12W), and power output at IAT (12 and 14W). No difference was found between groups, but ThT required significantly (p < 0.001) less time than pyramidal training to achieve the described improvements (59 ± 1 min/week vs. 76 ± 11 min/week). Comparison of isocaloric training intensity distributions revealed no significant differences between groups (Pyramidal: 170 ± 43 kJ/session, ThT: 175 ± 35 kJ/session, p = 0.10). Pyramidal and isocaloric threshold training resulted in comparable effects on endurance capacity in cancer survivors, with ThT requiring significantly less time for these effects.