There was no significant effect on muscle strength
after the MA or EA sessions. There are reports in the
literature of increased muscle strength after MA,
demonstrated only in another muscle group, the
biceps brachii.34 The status of the weakness of the
quadriceps muscle as a risk factor in patients with
knee OA is still controversial,39 although a relationship
is often found in this population.40
In the present study the EA group showed a slight
trend towards greater treatment effectiveness based on
the increase in the PPT, which was not significant.
Some studies suggest that PPT assessment must be performed
in patients with knee OA because it allows
evaluation of the local and generalised sensitisation.35
High- and low-frequency TENS increased PPT in
patients with knee OA after a single treatment
session.38 The difference between the characteristics of
the therapeutic modalities (TENS vs MA or EA) may
be responsible for the discrepancy in the observed
results.