Purpose: To estimate, upon competition heart rate (HR), exercise intensity
during time trials (TT) in professional road cycling. Methods: Eighteen wor
ld-class cyclists completed an incremental laboratory cycling test to asses
s maximal power output (W-max), maximal HR (HRmax), onset of blood lactate
accumulation (OBLA), lactate threshold (LT), and a HR-power output relation
ship. An OBLA(ZONE) (HROBLA +/- 3 beats.min(-1)) and a LTZONE (HRLT +/- 3 b
eats.min(-1)) were described. HR was monitored during 12 prologue (<10 km,
PTT), 18 short (<40 km, STT), 19 long (>40 km, LTT), eight uphill (UTT), an
d seven team (TTT) time trials. A HR-power output relationship was computed
to estimate each cyclist's power output during TT racing from competition
HR. Competition training impulse (TRIMP) values were estimated from HR and
race duration. Results: %HRmax were 89 +/- 3%, 85 +/- 5%, 80 +/- 5%, 78 +/-
3%, and 82 +/- 2% in PTT, STT, LTT, UTT, and TTT, respectively. The amount
of TRIMP were, respectively, 21 +/- 3, 77 +/- 23, 122 +/- 27, 129 +/- 14,
and 146 +/- 6. Competition HR values relative to HROBLA and HRLT were, resp
ectively, 100 +/- 3%, 114 +/- 8% in PTT, 95 +/- 7%, 108 +/- 9% in STT, 89 /- 5%, 103 +/- 8% in LTT, 87 +/- 2%, 101 +/- 5% in UTT, and 91 +/- 4%, 105
+/- 11% in TTT. Conclusions: %HRmax, TRIMP and time distribution around HRO
BLA and HRLT reflected the physiological demands of different TT categories
. HROBLA and HRLT were accurate intensity markers in events lasting, respec
tively, less than or equal to 30 (PTT and STT) and greater than or equal to
30 min (LTT, UTT, TTT).