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.