Deep dry needling in the active myofascial trigger point in the upper trapezius muscle. The muscle fibers were repeatedly perforated by rapidly inserting and partially withdrawing the needle from the MTrP until 4 local twitch responses were elicited.

Deep dry needling in the active myofascial trigger point in the upper trapezius muscle. The muscle fibers were repeatedly perforated by rapidly inserting and partially withdrawing the needle from the MTrP until 6 local twitch responses were elicited.

Deep dry needling in the active myofascial trigger point in the upper trapezius muscle. The muscle fibers were repeatedly perforated by rapidly inserting and partially withdrawing the needle from the MTrP until no more local twitch responses were elicited.

The needle was inserted 1.5 cm away from the trigger point in the trapezius muscle and withdrawn without any consecutive insertion.

Visual analog scale. A 100mm VAS, ranging from 0mm (no pain) to 100mm (worst imaginable pain).

Visual analog scale. A 100mm VAS, ranging from 0mm (no pain) to 100mm (worst imaginable pain).

Three consecutive trials of pressure pain threshold on the active trigger point at a rate of 1 kg/sec at intervals of 30 seconds were conducted.