Your arms swing in opposition to your legs. That swing balances the twist your legs create, and lab studies found that running with your arms held still costs more energy (about 3-13% more, depending on how the arms were held). The goal is a loose, natural swing: bent elbows, quiet shoulders, soft hands, no forced pumping.
Bend and swing
Bend your elbows to roughly 90 degrees as a starting point, and let your arms swing forward and back from the shoulder. Studies have not shown that one exact elbow angle saves energy, so settle where it feels easy.
the arm swings from the shoulder like a loose pendulum.
Let each arm move with the opposite leg, and let the arm speed follow your legs. When your legs go faster, your arms go faster too. You don't need to drive your legs with your arms; research suggests the swing is mostly powered by the lower body.
arms and legs in one rhythm, no extra effort up top.
Hands and path
Make a gentle fist, as if holding something you don't want to crush. Don't clench.
thumbs resting lightly on fingers, forearms soft.
Keep the swing compact: hands don't rise too high or punch far forward. A slight inward angle as your hands come forward is normal. A study of recreational runners found no advantage to a strict straight forward-and-back swing over the mild crossover style common in distance runners.
a small, easy arc, not a big reach.
Stay loose
Keep your shoulders low and level, away from your ears. Every so often, check in and shake your arms out to release tension.
shoulders heavy and down, neck long.
If you carry a bottle or phone, switch hands every so often so one arm isn't held still or stiff for the whole run.
both arms swinging evenly.
Feel it
Loose arms that keep time with your legs without effort. Your shoulders stay down, your hands are soft, and your upper body stays quiet instead of twisting. If your shoulders creep up or your fists tighten, shake out your arms and settle back into an easy swing.
Fix-its
- Your shoulders ride up toward your ears Drop them, keep them level, and shake your arms out for a few strides.
- You clench your fists Switch to a gentle fist, as if holding something fragile.
- Your arms swing too high or too big Keep the swing compact. Let the arms follow your leg rhythm rather than pumping hard.
- You hold your arms still or stiff (or carry something in one hand the whole way) Let both arms swing freely. Holding them still makes your shoulders and hips twist more and costs more energy. Swap hands if you carry something.
- You force a rigid, perfectly straight swing Relax. A slight inward path of the hands is normal and not shown to be a fault.
Drill
- Standing arm swing: stand tall, elbows bent, and swing your arms from the shoulder in an easy rhythm. Check that your shoulders stay down and your hands stay soft.
- Shake-out resets: during an easy run, let your arms drop and shake them loose for a few strides, then return to a relaxed swing. Repeat whenever you notice tension.
- Body scan: on an easy run, check hands, shoulders, and jaw from time to time and release any tension you find.
- Film yourself from the side and the front on an easy run to see your elbow bend, shoulder height, and how big your swing is.
Sources
- Arellano & Kram — The metabolic cost of human running: is swinging the arms worth it? J Exp Biol (2014)
- Pontzer, Holloway, Raichlen & Lieberman — Control and function of arm swing in human walking and running, J Exp Biol (2009)
- Hinrichs, Cavanagh & Williams — Upper extremity function in running. I: Center of mass and propulsion considerations, Int J Sport Biomech (1987)
- Yegian, Tucker, Gillinov & Lieberman — Straight arm walking, bent arm running: gait-specific elbow angles, J Exp Biol (2019)
- HSS (Kate Baird) — Proper running form (2024)
- ACE (Nicole Thompson) — 5 tips for optimizing running form (2024)
Last checked 2026-10-25.