Runner's knee, or patellofemoral pain, is a dull ache behind or
around the kneecap that shows up a few miles in and comes back with
every mileage build. It's one of the most commonly recorded running
injuries in
injury surveillance.
A running video can help you describe your stride, but it cannot
establish why your knee hurts. A side view shows landing position
and step rhythm; pelvic drop is assessed from a rear view. Training
changes and other factors may matter alongside movement patterns.
This page explains what GaitLab Coach looks for when you flag knee
pain before an analysis. For the drills and the week-by-week plan,
read the full article linked at the bottom.
When your foot lands well ahead of your hips with a nearly straight
knee, the ground pushes back against your direction of travel. That
braking force loads the knee in its least protected position, with
the quadriceps pulling the kneecap hard against the femur. Repeat it
a few thousand times per run and the tissue behind the kneecap gets
irritated.
A low cadence makes this worse. Fewer, longer steps mean more time
in the air and a bigger drop onto each landing. A pelvis that dips
on each stance lets the thigh rotate inward and changes how the
kneecap tracks in its groove.
None of this is something you can feel at running speed. Ground
contact lasts a fraction of a second. Pause a video at the moment
your foot touches down, though, and it's easy to see.
Pain that rises on hills, long runs, or after sitting for a while
A gradual build over weeks rather than one sharp event
Relief with rest, then a return as soon as mileage goes back up
What different camera views show
Landing position
Pause at first contact. A foot well ahead of the hip line with a
more extended knee is a pattern worth discussing; video alone
cannot measure the force at the kneecap.
Cadence
Counted on your phone from the motion in the video, not
estimated. The research supports raising it 5–10% from your own
baseline (Sports Health, 2025).
Knee angle at contact
A slightly bent knee absorbs. A straight one transmits the
impact spike up the chain.
Pelvic drop
Assessed from behind, not from a side view. A visible waistband
dip is an observation to discuss, not proof of weakness or the
cause of pain.
What GaitLab Coach does with it
When you flag runner's knee before recording, the analysis weights
its findings toward the patterns that load the patellofemoral joint.
The full report ranks findings by importance, explains what they
mean, and suggests a cue and drill to practice.
The 4-week plan then leads with the highest-leverage change, usually
a cadence bump, and adds hip strength work rather than handing you
five cues at once. Focused, progressive programs are what the
retraining literature supports (Bramah et al., JOSPT 2022).
Findings ranked by how much they matter for knee load, not by how
interesting they are
A re-test after the plan, so you compare measurements rather than
sensations
Works on a training partner's clip too, so you can check each
other
When form isn't the culprit
Kneecap pain isn't always a form problem. A sudden jump in mileage,
a lot of downhill, a footwear change, or poor recovery can all set
it off with perfectly ordinary mechanics. A knee that swells, locks,
gives way, or hurts at rest needs an in-person assessment from a
physio or sports-medicine professional first. GaitLab Coach flags
movement patterns linked to overuse risk in the research; it can't
tell you what's going on inside the joint.
A side view can show landing position and step rhythm; a rear view is needed to assess pelvic drop. Video cannot establish the cause of knee pain or measure joint forces. Persistent or worsening pain warrants a clinical assessment.
Which form change helps runner's knee most?
For most runners the first lever is cadence. A 5–10% increase
above your own baseline reduces knee and hip joint loads without
hurting running economy, and it pulls landing position back
under the body at the same time.
How does flagging knee pain change the analysis?
The findings are weighted toward the mechanics that load the
patellofemoral joint, and the 4-week plan starts with those. The
same video would be read differently for a runner who flagged
Achilles pain.
Use this guide to understand the movement patterns discussed in a
report. In GaitLab, select the relevant injury context before your
analysis, or skip injury selection for general form feedback.
Start with free form highlights and slow-motion replay. Ranked
findings and the 4-week drill plan require the optional Premium
unlock. A video-based form assessment cannot confirm the cause of
pain.
Record 15–60 seconds from the side, flag runner's knee, and get the
patterns that matter for your kneecap ranked in order. Free to start.
The full report, with the 1–10 score, ranked findings, and 4-week
plan, is a one-time $4.99 unlock.