REF-793 · Fintelman et al., 2015 · Journal of Sports Sciences, Vol. · Paper · PubMed

The Effect of Time Trial Cycling Position on Physiological and Aerodynamic Variables

B+moderate evidenceMeasured on trained to highly trained athletesWritten before October 2026, being re-checked

Nineteen well-trained male cyclists did incremental ergometer tests at their preferred torso angle and at 0, 8, 16 and 24°, with gas exchange, gross efficiency, peak power output (PPO), heart rate, cadence and frontal area recorded.

Every maximal value fell as the torso got lower (P < 0.001), and the 0° (flat-back) position affected the metabolic and physiological variables significantly more than all the other positions. At fixed submaximal intensities (60, 70 and 80% PPO) the variables rose both with intensity and with lower torso angles.

The authors conclude that a trained cyclist has to trade aerodynamic drag against physiological functioning.

Participants

n=19 well-trained male cyclists (abstract: "Nineteen well-trained male cyclists"). Age and fitness values are not given in the abstract.

Protocol

Five positions on a cycle ergometer: preferred torso angle, and torso angles of 0, 8, 16 and 24°.
Incremental test in each position: oxygen uptake, carbon dioxide output, minute ventilation, gross efficiency, PPO, heart rate, cadence.
Constant submaximal stages at 60, 70 and 80% PPO.
Frontal area recorded as the estimate of aerodynamic drag (not a wind-tunnel or field drag measurement).

Key Results

Maximal values of all variables in the incremental test decreased with lower torso angles (P < 0.001) — including PPO.
The 0° torso angle affected the metabolic and physiological variables significantly more than all other positions.
At 60, 70 and 80% PPO, all variables increased significantly with intensity (P < 0.0001) and with decreasing torso angle (P < 0.005).
The abstract gives no values for PPO, frontal area or any variable in any position, so the size of the trade-off cannot be read from it.

Practical Application

In 19 well-trained male cyclists tested at five torso angles, every maximal value, peak power included, fell as the torso got lower (P < 0.001), and the flat-back 0° position cost significantly more than all the others; the authors conclude that a trained cyclist must trade aerodynamic drag against physiological function. Getting lower is not free: the aero gain is paid for in power, and the cost looked steepest at the flattest torso.
At the same submaximal share of PPO, the physiological variables were higher in lower positions (P < 0.005), so a given effort feels and costs more in a deeper position.
Do not quote a watts figure for the position cost from this entry: the abstract reports none.
Inference, not tested here: because the flat-back position stood out from all others, a rider lowering the torso should retest power in the new position before racing in it rather than assume the old number carries over (REF-201 shows the same for critical power).
Not from this paper; the base's own practice: on a flat, fast time trial the aero side of the trade usually wins, on a hilly one the power side matters more (REF-490 lists air resistance and gravity as the resistive forces).

Limitations

Laboratory ergometer, not road riding; frontal area stands in for drag and is not a drag measurement.
Men only; well-trained cyclists; position order and familiarisation are not described in the abstract.
Incremental and submaximal tests, not a time-trial performance; the abstract reports directions and P values only, no magnitudes.
Written from the abstract and record metadata only (full text not read).
How this entry was checked and changed
Why this level

within-subject comparison of five positions, n=19; order of conditions not given in the abstract