Insoles and orthotics
Evidence: limited
Foot orthoses can ease symptoms in some conditions and may modestly lower injury risk in specific populations, but they work mainly by altering comfort and load distribution rather than by correcting alignment. Custom devices generally do not outperform good prefabricated insoles for most people, and routine use to prevent injury in healthy runners is not well supported.
Not medical advice
This is a general knowledge base, not medical or dietary advice. If you are injured, unwell or weighing up a supplement or a change to your diet, speak to a doctor, physiotherapist or registered dietitian who knows your situation.
A foot orthosis is an insert worn inside the shoe. Two broad kinds exist: prefabricated insoles bought off the shelf, and custom orthotics moulded to an individual foot, usually by a podiatrist. Both are widely sold to runners on the promise of correcting how the foot moves.
The old rationale versus the modern view
The historical case for orthoses rested on alignment. A foot that rolls inward too much (overpronation) or has a particular arch height was thought to throw the leg out of line, and an orthosis was prescribed to prop the arch and steer the foot back toward “neutral”. This is the same static foot-type model that underpinned the pronation-and-arch system for running shoes, and it has not held up: matching a device to foot type does not reliably prevent injury, and the link between static foot posture and injury is weak.
The modern view is that orthoses, when they work, work for different reasons. They change where load falls across the foot and how comfortable the shoe feels, and they shift forces at the joints up the chain, rather than mechanically realigning a misaligned foot. The effect is one of load redistribution and symptom relief, not correction.
What the evidence shows
For some established conditions, orthoses earn a place as part of management. In plantar heel pain they give modest medium-term pain relief, though the effect is small and of uncertain clinical importance (Whittaker et al. 2018); see plantar fasciopathy. In patellofemoral pain, orthoses improve knee function and the ability to play sport but do not reliably reduce pain intensity; physiotherapy and gait retraining outperform them, and orthoses are best used as an add-on to exercise rather than instead of it (Heliyon 2022).
For preventing injury in runners who are not yet hurt, the evidence is weaker and mixed. A meta-analysis dominated by military-recruit trials found foot orthoses reduced overall injuries and stress fractures, with shock-absorbing insoles showing no such benefit, but trial quality was variable and the populations were not recreational runners (Bonanno et al. 2017). That signal does not transfer cleanly to a healthy runner deciding whether to buy insoles, and routine prophylactic use is not well supported. This is the same caution applied to orthoses in the wider overuse-injury picture.
Across conditions, custom orthotics generally do not outperform good prefabricated insoles for most people. The expensive, individually moulded device buys little over a sensible off-the-shelf one for the typical runner, which fits the load-and-comfort explanation: it is the support and cushioning the foot experiences that matters, not how precisely the shape was copied.
The comfort filter
The practical rule that survives the evidence is the comfort filter, the same idea that governs shoe choice: an insole that feels comfortable and reduces symptoms is a reasonable thing to use, while chasing biomechanical “correction” is not. If a cheap insole makes a niggle better, that is a legitimate result on its own terms; if it is uncomfortable, or bought to fix an alignment problem it cannot fix, it is unlikely to help. The device is judged by the individual’s response, not by a foot-type chart or a gait-scan readout (see biomechanics and gait).
None of this displaces the core of injury management, which is managing load and building tissue capacity through progressive strengthening, the most reliable lever in the sport. Orthoses are at best an adjunct to that, and at the minimalist end of the spectrum some runners prefer to train the foot directly rather than support it (see barefoot and minimalist running).
When to see a podiatrist
Trying a comfortable off-the-shelf insole is low-risk. Custom assessment is worth seeking when pain is persistent or recurrent despite sensible load management, when there is a structural foot problem or a history of stress fracture, or when a clinician thinks a tailored device fits the rehabilitation plan. The device should support a load-and-strength programme, not replace it.