Most Evidence is Irrelevant

This study just caught my eye. Just published, looked good.

At first glance you might think this turned out well

Conclusion

The risk of developing PF is increased after procedures that might create transient core weakness. Given the results of this model, attention to core strengthening and rehabilitation may be of value in the treatment and prevention of PF.

Based on the title and the conclusion, most practitioners are going to start recommending core exercises to every patient that comes in with plantar fascitis.

Hold your horses! Let's look at what they did.

They looked for an increase in plantar fascitis in women who had a caesarian section vs those who had a natural delivery and also in people who had lumbar disc surgery compared with those who had a chest infection.

Did they measure core weakness in patients with plantar fascitis? No. They just presumed it was there after these procedures. Strike 1.

This was a MASSIVE study involving 260,000 enrolments in the caesarian portion and one million in the disc surgery portion. Admittedly, this was an observational data-only study but even so, huge numbers and expense.

One might have hoped for some pretty significant results?

Results
Women who underwent cesarean section had 24.1% greater odds of Plantar Fascitis within 12 months of delivery compared to vaginal births... Patients who underwent posterior lumbar fusion surgery had 11.7% greater odds of developing Plantar fascitis.

Not too shabby - until you dig into the figures.

The Cesarian group had an incidence of PF of 1.16% compared to 0.97% in the natural delivery group.

This means that there were .19% more cases in the cesarian group - which means 2 women per thousand who developed plantar fascitis in the year following. In the disc surgery group, there were even less.

Their conclusion?

Our study provides evidence that core weakness may have an association with PF, and thus, core strengthening modalities could provide benefit in PF therapy.

Their study proves nothing of the sort. It showed two women in a thousand who had a caesarian developed plantar fascitis compared to women who had a natural birth. Whether this was due to core weakness or not was not shown in this study, it was a theoretical association only.

This is yet another example of a shoddy study, reaching shoddy conclusions that are worthless, yet could influence practitioners to implement unnecessary treatments on thousands of patients. Published evidence usually isn't worth the money, time or paper it's written on.