Foam rolling and mobility tools
Evidence: limited
A small, short-lived range-of-motion gain and some relief of perceived soreness, with negligible effect on muscle function. Cheap, harmless and fine to use; just do not expect a training benefit.
Keep it in proportion
This is one of the last few per cent, at most. It pays off only once the basics are already in place: consistent volume, sleep and adequate fuelling. Most runners gain far more from those than from anything on this page.
A foam roller, or a lacrosse ball for smaller and harder-to-reach spots, applies pressure to muscle and fascia. A meta-analysis finds foam rolling produces small, short-lived increases in range of motion and small reductions in perceived muscle soreness, with negligible effects on actual muscle function (Wiewelhove et al. 2019). Rolling before a run can slightly aid flexibility and sprint performance without the brief strength loss long static stretching can cause; rolling afterwards slightly reduces how sore the muscles feel.
In the league table of recovery modalities this is firmly in the perceptual camp, but it has advantages the gadgets lack: it is cheap and essentially harmless. A lacrosse ball costs almost nothing and lets you work a specific tight spot. So the verdict is permissive rather than dismissive: if rolling helps you feel looser and readier to run, it is a reasonable, low-cost habit. Just hold it to that standard, a comfort and mobility aid, not a way to recover faster or train harder.
A spot that keeps tightening up is worth treating as a signal rather than a nuisance. Persistent tightness in the same place often points to an overworked muscle, frequently one compensating for a weaker link, so strength work is the better candidate for removing the cause while rolling only eases the symptom (see massage for the fuller version of this point).