The study
This was a randomised controlled trial in 45 physically active adults with flexible pes planus, split into three groups. One group received joint-oriented manual therapy, mobilisation of the ankle and foot joints. A second received soft-tissue work targeting the triceps surae, Achilles tendon and plantar fascia. The third was a control group.
The primary outcome was weight-bearing ankle dorsiflexion, measured alongside foot posture (navicular drop and the Foot Posture Index), dynamic balance on the Y-Balance Test, and muscle mechanical properties, before and after a single session.
What they found
Both manual therapy approaches improved the foot posture measures immediately, so the hands-on work did produce a measurable short-term change. The joint-oriented group came out ahead on two fronts in particular: they gained more ankle dorsiflexion and more forward reach than the soft-tissue group.
The important limitation, and the authors are upfront about it, is that this was only measured immediately after a single session. There was no follow-up, so the study tells you that joint mobilisation can shift these measures in the moment, but it says nothing about whether that change lasts a day, a week, or at all.
What it means for your practice
Treat this as support for using manual therapy tactically rather than as a standalone correction for flat feet. When limited ankle dorsiflexion is the thing holding a patient back in the short term, for example stopping them squatting, loading or moving well, targeted joint mobilisation can open a window of better movement.
The key is what you do with that window. Because the effect is only shown for a single session, the manual therapy needs to be followed straight away by the work that builds lasting change: strengthening, progressive loading, gait and movement retraining, and footwear or orthotic strategies where they are indicated. The hands-on work gets the patient into a better position; the active work is what makes it stick.
What you should not do is sell joint mobilisation as a fix for flat feet on the strength of this study, because it simply does not show durable change. It is a way to create a better starting point for the real rehab, and that is a perfectly good reason to use it.
Bottom line
Joint-focused manual therapy can produce an immediate improvement in ankle movement and foot posture in flexible flat feet, and it beat soft-tissue work for dorsiflexion in this trial. But the effect was only measured after one session, so use it to open a window for better exercise and gait work, not as a correction in its own right.