The Kinetic Chain: Feet, Knees, Hips, Back

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People with long-standing heel pain often report something odd: a few months in, their knee starts complaining. Or their hip. Or their lower back — on the same side, having never been a problem before.

That is not coincidence, and it is not a mystery. It is what happens when you change how you walk for a few thousand repetitions a day.

What "kinetic chain" means

Your leg is a linked system. Foot, ankle, knee, hip, pelvis, spine — each segment's position and motion affects the ones above it.

Change one link and the others compensate. They have to; the job of getting you from A to B still has to be done. The compensation is usually invisible to you and completely obvious to your tissues, because it repeats every single step.

The average person takes several thousand steps a day. A small change in mechanics, multiplied by that, is a large change in cumulative load.

The most common route: limping

This is the biggest one, and it is worth taking seriously precisely because it feels minor.

When your heel hurts, you unconsciously avoid loading it. You shorten your stance time on that side, land differently, roll off sooner, and take slightly more weight on the other leg.

What that does upstream:

  • The other side works harder. More load, more often, on a leg that was doing a fair share already. Contralateral knee and hip pain is a very common secondary complaint.
  • The painful side's hip abductors work differently. Shortened stance time changes how the pelvis is stabilised.
  • The pelvis and lower back adjust. Asymmetric gait shows up as asymmetric loading through the lumbar spine.

The practical implication: if your foot pain has lasted months and you have developed knee, hip or back pain on either side, the limp is the first suspect — and treating the new pain without addressing the limp is treating a symptom of a symptom.

The link that runs the other way: the ankle

The more interesting direction is downward, and it is where the useful intervention lives.

Walking requires the shin to travel forward over the planted foot — ankle dorsiflexion. If the ankle cannot provide the needed range, the motion is borrowed:

  • Early heel lift, throwing you onto the forefoot for longer — which means more time with the plantar fascia under tension via the windlass mechanism
  • Arch collapse, as the midfoot flattens and rolls inward to find the range the ankle will not give
  • Toe-out, so you roll over the inside of the foot instead of straight over the front
  • Knee and hip compensation further up

This is not a marginal factor. In the Riddle (2003) matched case-control study, restricted ankle dorsiflexion showed the strongest association with plantar heel pain — ahead of body weight and hours on your feet.

So the ankle is the pivot of the whole chain, and it is also the cheapest thing to change: two minutes a day, no equipment.

Test it

The knee-to-wall test:

  1. Face a wall, one foot forward, pointing straight at it
  2. Keeping your heel flat, bend your knee to touch the wall
  3. Slide the foot back to the furthest point where the knee still reaches with the heel down
  4. Measure wall to big toe

Around 10 cm or more is generally considered adequate; under about 5 cm suggests real restriction. Compare left and right — a clear asymmetry is informative in itself, particularly if the tighter side is the painful one.

If you are short, stretch both calf muscles daily. They need different knee positions: knee straight for the gastrocnemius, knee bent for the soleus. Most people have only ever done the first.

Why this matters for treatment

Three practical consequences.

1. Treating only the sore spot often disappoints. If the load reaching your heel is being generated by a restricted ankle and an altered gait, working on the heel alone addresses the symptom's location rather than its cause. This is why the clinical guideline recommends stretching the calf alongside the fascia, and why so many people improve temporarily and then relapse.

2. New pain elsewhere is a signal, not a separate problem. Knee or hip pain appearing months into a foot problem usually means your gait has changed enough to matter. That is a reason to address the limp — through pain control, load management and progressive loading — rather than to start a separate treatment programme for the knee.

3. It cuts both ways. A hip that does not extend properly, or a stiff big toe, can change how your foot loads. A good assessment looks above and below the painful area, which is a reasonable thing to ask for if you have been treated locally without progress.

What not to conclude

Two cautions, because this idea gets oversold.

Not every ache is connected. Kinetic chain reasoning can be stretched into explaining anything, and "your shoulder pain is caused by your foot" is usually a claim without evidence. The well-supported version is local and mechanical: adjacent joints compensate for each other, and gait changes load tissues differently.

Correlation is not a treatment plan. Finding a restriction somewhere does not prove it caused your symptoms. The Riddle study establishes association, not causation — though the anatomy gives a clear reason for the arrow to point the way clinicians read it.

FAQ

Can plantar fasciitis cause back pain? Indirectly and commonly — through limping. Months of altered gait loads the pelvis and lumbar spine asymmetrically.

Why does my other leg hurt now? Because it has been taking more of your weight. Contralateral pain is one of the most common secondary complaints in long-standing foot problems.

Should I treat the knee or the foot first? Usually the thing driving the altered gait. If the foot is the reason you are limping, addressing it typically resolves the compensation.

Does fixing my ankle range fix everything? No, but it is the highest-value cheap intervention available, because it is the strongest identified risk factor and it changes in weeks.

Sources

  • Riddle DL, Pulisic M, Pidcoe P, Johnson RE. Risk factors for plantar fasciitis: a matched case-control study. Journal of Bone and Joint Surgery (Am), 2003
  • Hicks JH. The mechanics of the foot: II. The plantar aponeurosis and the arch. Journal of Anatomy, 1954
  • Journal of Orthopaedic & Sports Physical Therapy — Heel Pain–Plantar Fasciitis: Revision 2023 (APTA clinical practice guideline)

This article is general education, not medical advice. Persistent pain in more than one joint should be assessed by a qualified clinician.