treadmill runner wrote:
My personal experience is that treadmills are harder especially for faster speeds at longer durations:
"speed workouts": about the same/ easier outdoors (Outdoors 3:30min/km feels similar to 3:45min/km on tm)
"longer tempos(>13k)": easier outdoors (if temp. and humidity are similar to indoors) (Outdoors I need to "hold back"/save energy to slow down to 4min/km the entire workout. On treadmill I need to focus a lot(+sweat a LOT more) to not fall off the belt after 5km...)
Almost no difference(/ sometimes feels easier on tm(probably because air quality is sometimes better/more stable in my home but running on a quiet trail outdoors can feel MUCH more enjoyable))
Easy/ aerobic runs
Check real inclination by clinometer at 0% setup. A lot of people says it harder, others says it easier, just check inclination and you will find answer why is harder or easier vs outdoor.
Check speed calibration, if treadmill speed is lower vs outdoor, but real inclination 1.5% and more, your treadmill will be anyway harder vs outdoor at same speed what is showing on display. If the treadmill speed is correct vs outdoor, but at 0% incline setting real inclination is more, your treadmill will be far way harder vs outdoor too.
For fun, put your data from treadmill with real inclination (checked by clinometer) here:https://42.195km.net/e/treadsim/
You will see why is so damn hard to run on a treadmill vs outdoor.