Plant both poles at once and push off hard: learn when double poling works on steep climbs and when fatigued, without losing rhythm or safety.
When do you use both poles at once in trail running? The honest answer: when the climb is so steep or you get so tired that the diagonal rhythm no longer gives enough push, and when you want to use both arms powerfully at the same time. You plant both poles at foot height or slightly ahead, push yourself forward with arms and chest and step after.
An honest word on the data first: I found no dedicated study on double poling in trail running. What is documented concerns poles in general. When walking steeply (treadmill, 10–39°), perceived effort with poles was 14–19 % lower at most steps from 15.5° upward, and from 25.4° the energy cost per metre of climb also fell by about 2–3 % [1]. At maximal effort uphill, trail runners were faster with poles; at easy pace there was no advantage [2]. A review notes: upper-body and trunk muscles are more active with poles, pressure under the feet falls [3]. The technique itself (simultaneous, at foot height) is practice standard.
Expect several outings until you master switching between diagonal and double in flow.
Plant both poles at once in front of the body, about at foot height, shoulder-width apart. Your torso leans forward, arms slightly bent. The pole tips point diagonally backward. You do not pull yourself with the poles, you push yourself forward.
Milestone: you plant both poles at the same time 10 times on level ground, evenly.
Push yourself forward with both arms and take one step after. Your trunk works with you. On steep ground you take two steps per pole plant, on easier terrain one step. Decide by feel: the number of steps should fit your breathing rhythm.
Milestone: you walk 2 minutes in double-pole rhythm without the rhythm breaking.
Switch with changes of terrain: diagonal on irregular ground, double on even, steep sections. Make the switch in calm moments, not in the middle of a bend.
Milestone: you switch between both techniques four times in one climb without stopping.
When your legs tire, double poling is an extra gear. When fatigued, walking uphill with poles cost less energy and foot force was lower [4]. The pattern shifts work to arms and trunk.
A practical anchor: if your breathing runs away in diagonal rhythm even though your legs still want to go, that is the moment for 30 seconds of double poling. If your arms burn, go back to diagonal (practice).
Milestone: you recognise when diagonal is no longer enough and switch deliberately.
Use double poling deliberately as a breather: use it for 30–60 seconds when your heart rate rises, then return to the diagonal rhythm. The gain lies less in saving energy than in feel: with poles, perceived effort on steep ground was lower [1].
On even, steep sections and when you get tired. On uneven ground diagonal is usually easier to control. No study on double poling in trail running exists; the recommendation is practice.
Only a little. On very steep ground the energy cost per metre of climb fell by 2–3 % with poles [1]. Perceived effort was clearly lower [1]. At easy pace there was no advantage [2].
No. Fitting length and straps matter. Longer poles lengthened the thrust phase in one review [3]. Pole mass barely affects oxygen consumption [3].
Yes, upper body and trunk are more active with poles [3]. Allow adaptation time so shoulders and forearms are not overloaded.
Hands on Thighs: Climbing Steep Slopes Without Poles