How to fix your arm swing when running

You fix your arm swing by bending the elbows to about 90 degrees, relaxing the hands, and driving the elbow back rather than the hand forward. The arms should swing from the shoulder along the line you are running, not across your chest. That is the whole of it. Most arm swing problems are one of three things: elbows too open, hands too tight, or arms crossing the body.

What good arm swing looks like on video

Side view. Pause anywhere mid-stride and look at the elbow angle. Around 90 degrees is the target, with a little opening on the back swing and a little closing on the front swing. The hand should pass near the hip on the way back. It should not rise above the chest on the way forward. The shoulders stay down and still.

Front view. Watch the hands. They should move forward and back close to the sides of the body. If a hand crosses the middle of your chest, the arm is swinging across. Watch the shoulders too. They should stay level and not rotate toward the camera with each step.

The three common faults

1. Elbows too open. The arm hangs at 120 degrees or more, hand low and near the thigh. The arm is longer, so it swings slower. Slow arms make slow legs. Runners who do this often have a low cadence without knowing why.

2. Hands too tight. Fists clenched, shoulders creeping up toward the ears, neck stiff. Tension in the hands travels up the arm and into the shoulders. It costs energy and often shows as a forward head. See how to check your running form at home.

3. Arms crossing the body. The hands swing in toward the midline and across. This twists the torso. The hips and shoulders rotate against each other every step, and the legs have to correct for it. Runners who cross often show side-to-side movement on a front view.

Why it matters

arm bend and legs are tied together. The right arm swings with the left leg and the left arm with the right leg. Quick, compact arms make it easier to hold a quick cadence. Long, slow arms pull cadence down. See how to raise cadence without a watch.

The arms also balance the twist from the legs. If they swing along the line of travel, they cancel the rotation of the hips. If they swing across, they add to it. Crossing arms is a common reason a runner feels they are working hard but not moving fast.

Arm swing has a smaller effect on injury than foot landing does. It has a real effect on how easy running feels and on how fast your feet turn over.

The one cue

Elbows back, hands loose.

Elbows back fixes the direction of the swing. The arm drives back from the shoulder, and the front swing takes care of itself. Hands loose fixes the tension. Imagine holding a crisp in each hand without breaking it, or a pen you do not want to drop.

Use it for 30 seconds, four times per easy run. Then let it go. If the shoulders start to rise, shake the arms out for a few steps and try again.

A 4-week plan

Arm swing changes faster than foot landing. Most runners feel the difference in two weeks and see it on video by week four. Three short sessions a week plus the cue on easy runs.

Weeks 1 and 2: position and rhythm.

Standing arm swing, 3 × 30 seconds. Stand tall, elbows at 90 degrees, swing from the shoulder. Watch yourself side-on in a mirror or window. Then do one set at a quick tempo to feel the elbow drive.
A-march, 3 × 30 seconds. Arm swings with the opposite leg, elbow back as the knee comes up.
Dead bug, 2 × 8 each side. Teaches the arm and opposite leg to move without the torso twisting.
Two easy runs with the cue "elbows back, hands loose" on for 30 seconds, four times.

Weeks 3 and 4: speed and carry-over.

A-skip, 3 × 20 metres. Quick, compact arms driving the rhythm.
Quick-feet strides, 4 × 20 seconds. Let the arms set the tempo and the legs follow.
Single-leg balance, 2 × 30 seconds each side, with arms swinging slowly in running position.
Glute bridge, 3 × 12.
One easy run with the cue on for every other kilometre. Check the hands on hills, where they tend to clench.

Film again at the end of week 4, side view and front view.

How to check it with Caden

Tap Run a new analysis and set up a side-on shot. Phone at hip height, 6 to 8 metres away, 10 to 20 seconds at easy pace.
On the results screen, read the Arm bend dial. It measures elbow angle across the stride. A note that the arms are too open or too closed tells you which way to go.
Read the Head position dial next to it. A forward head often comes with tight hands and high shoulders. Fixing one usually helps the other.
Tap Breakpoints, then Midstance. The skeleton overlay shows the elbow angle at that moment so you can see it, not guess it.
Film your own clip running toward the phone to see whether the hands cross the centre line. Caden does not analyse that view. A shoulder line that tips each step on your footage is a clue that the arms are crossing.
Open the Exercises tab for the plan. Re-film in week 4 and open Before and after in Stats.

Caden measures the elbow angle from the side view. It does not measure how far the hands cross the midline. Use your own front-on clip and your eyes for that.

Mistakes

Pumping the arms forward. The drive is back. Forward takes care of itself.
Pinning the elbows at exactly 90. It is a target, not a lock. The angle opens and closes a little through the swing.
Fixing arms while ignoring feet. If foot landing is your lowest dial, start there. Arms are the second job.
Holding a phone or bottle every run. A weight in one hand pulls that side out of rhythm. Use a belt or vest when you can.
Only checking when fresh. Arms fall apart late in runs. Film the end of a long run once.

FAQ

What angle should my elbows be when running?

About 90 degrees, opening a little on the back swing. Much more open than that makes the arm slow and pulls cadence down. Much tighter than that lifts the shoulders.

Why do my arms cross my body when I run?

Usually a mix of habit, tight shoulders and a torso that rotates too much. The cue "elbows back" straightens the swing. The dead bug and single-leg balance help the torso stay still.

Does arm swing matter for running speed?

Yes, mainly through cadence. Quick, compact arms help the legs turn over quickly. Crossing arms add twist the legs have to cancel out. Fixing arms will not make you fast on its own, but it makes a quick cadence easier to hold.

Should my hands be open or closed?

Loose and relaxed, somewhere between open and a soft fist. Clenched fists send tension up into the shoulders and neck.