DISCUSSION
This study aimed to test the immediate effects of a single session of MA or EA in patients with knee OA. There was a significant reduction in pain intensity and in the execution time of the TUG test in both of the groups. However, there was no significant increase in the muscle strength or the PPT. In addition, there was no significant difference between the groups for all the outcomes evaluated.
The reduction in the pain intensity after one session of MA can be explained by the release of neurotransmitters such as endorphins and monoamines (serotonin and noradrenaline) which block pain messages.12 13 37 The improvement resulting from EAcan be explained by the release of the same substances that are released in MA, in addition to the release of enkephalins, β-endorphins and endorphins which activatem the m and δ-opioids and of dynorphins which activate the κ-opioid receptors,19 31 which could potentiate the effects of the treatment. However, in