Treadmill vs Outdoor Running: Which Is Better for Training?

Jones and Doust’s 1996 study tested nine trained male runners over short bouts at speeds from 2.92 to 5 metres per second. A 1% treadmill grade approximated the energetic cost of outdoor running under those study conditions. It did not establish a universal correction for all runners, treadmills, speeds or weather.

Ventilation, room temperature, treadmill calibration and incline can change how a given speed feels. Set an effort you can sustain for the intended session. A recent outdoor performance is more directly relevant to an outdoor race than assuming a treadmill time is interchangeable.

A treadmill can provide a repeatable setting and avoid poor outdoor conditions. Check the room’s temperature, use the safety features and allow time to become familiar with speed changes. A consistent surface is not proof of lower injury risk.

Outdoor sessions let you practice the turns, surfaces, hills and conditions of a target race. Include them when practical, but there is no evidence here for a rule that everyone must train mainly outdoors for the final six to eight weeks.

Start with a manageable session when changing environments. Adjust pace to the actual effort rather than automatically adding 1% incline or assuming a fixed adjustment period. Use whichever setting supports the session and your circumstances.