Case Studies in Physiology: Training adaptation in an elite athlete after breast cancer diagnosis

The aim of this study was to evaluate the capacity to return to competition of a 28-yr-old female 400-m hurdle elite athlete after a diagnosis of breast cancer. The study lasted 14 mo after diagnosis. She was tested four times (T1-T4) to measure body mass (BM), body mass index (BMI), percentage of total fat mass (TFM%), total fat-free mass (TFFM%), bone mineral density (BMD), one-repetition maximum (1RM), and maximal power (MP) in bench press and half squat, maximum oxygen uptake, and 400-m dash and hurdles. T0 (baseline time) was established with values before diagnosis. BM and BMI increased from T0 to T1 (5.3% and 5.2%) and remained stable. BMD experienced no change. TFM% values decreased from T1 to T4 (3.5%). TFFM% values increased from T1 to T3 (0.9%). During T1-T2, the athlete presented a global decline from T0 in 1RM_Squat, 1RM_Bench, MP_Squat, and MP_Bench (32.6%, 27.2%, 37.5%, and 27.6%, respectively). Results during T3-T4 were also lower for these parameters from T0 (23.3%, 20.6%, 23.4%, and 11%). During T1-T2, the V̇o_2max declined compared with T0 (1.8% and 6.4%), showing a small increase at T3 (+1%) and reaching the lowest level at T4 (9%). During T1-T2, the time record of 400-m dash (8.3%) and hurdles (7.4%) increased. However, a slight improvement was found at T3 (1.3% and 0.6%, respectively). The results of this case study reflect that exercise training improved body composition, maintained BMD and TFFM, but could not completely reverse the worsening of the cardiorespiratory, muscle strength and power, and running performance levels.NEW & NOTEWORTHY This case study follows an elite athlete and measures her performance during cancer treatment. It improves the knowledge on applied physiology showing the details of her training program and demonstrating the strong ability of the athlete to continue training and competing at a high level during antineoplastic treatment. Exercise training improved body composition but failed to restore previous cardiorespiratory, muscle strength and power, and running performance levels.