Exercise intensity and load during mass-start stage races in professional road cycling

Purpose: To evaluate exercise intensity and load during mass-start stages i n professional road cycling, using competition heart rate (HR) recordings. Methods: Seventeen world-class cyclists performed an incremental laboratory test during which maximal power output (W-max). maximal HR (HRmax), onset of blood lactate accumulation (OBLA), lactate threshold (LT) and a HR-power output relationship were assessed. An OBLA(ZONE) (HROBLA +/- 3 beats.min(- 1)) and an LTZONE (HRLT +/- 3 beats.min(-1)) were described. HR was monitor ed during 125 flat (<13 hn uphill, < 800-m altitude change; FLAT), 99 semi- mountainous (13-35 km uphill, 800- to 2000-m altitude change: SEMO), and 86 high-mountain (>35 km uphill, > 2000-m altitude change; HIMO) stages. Each cyclist's competition power output was estimated from competition HR and i ndividual HR-power output relationships. Competition training impulse (TRIM P) values and time spent at "easy," "moderate," and hard" zones were estima ted from HR and race duration. Results: Average %HRmax were 61 +/- 5%, 58 /- 6%, and 51 +/- 7% in HIMO. SEMO, and FLAT stages, respectively. and esti mated average power outputs were 246 +/- 44, 234 +/- 43, and 192 +/- 45 W. Competition HR values relative to HROBLA and HRLT were, respectively 69 +/- 6, 79 +/- 9% in HIMO; 65 +/- 7, 74 +/- 11% in SEMO; and 57 +/- 8, 65 +/- 1 0% in FLAT stages. The amount of TRIMP in HIMO, SEMO, and FLAT stages were, respectively, 215 +/- 38, 172 +/- 31, and 156 +/- 31. Percentage time spen t in the "moderate and "hard" zones was highest in HIMO (22 +/- 14, 5 +/- 6 %) followed by SEMO (15 +/- 13, 5 +/- 5%) and FLAT (9 +/- 7,2 +/- 2%) stage s. Conclusions: %HRmax time distribution around HROBLA and HRLT. TRIMP, and load zones reflected the physiological demands of different mass-start cyc ling stage categories. The knowledge of these demands could be useful for p lanning precompetition training strategies.