Segmental facilitation, originally proposed by Korr in the 1950s, suggests that certain spinal segments can become hyperexcitable, leading to chronic pain development. In a facilitated segment, neurons governing sensory, motor, and autonomic functions are in a state of heightened sensitivity, making them responsive to normally weak stimuli. Clinical signs include non-fatigable muscle weakness, brisk reflexes, muscle hypertonicity, tenderness upon palpation, and trophic changes like an orange-peel appearance in the affected segment's innervated areas. It's hypothesized that increased synaptic excitability in facilitated segments could cause vasoconstriction and reduced blood flow, contributing to trophic changes and muscle hypertonicity. Manual therapies like dry needling have been shown to alleviate muscle inhibition in the extremities. Previous studies have demonstrated that mobilization of the C5-6 joint can reduce non-fatigable weakness in shoulder external rotators primarily innervated by these segments. However, the neurophysiological effects of dry needling (DN) on muscle inhibition due to a facilitated segment remain unclear. While DN has been observed to increase local tissue blood flow, its potential to mitigate the clinical signs of segmental facilitation is uncertain. While DN has been observed to increase local tissue blood flow, its potential to mitigate the clinical signs of segmental facilitation is uncertain. Therefore, this project aims to investigate whether DN applied at a facilitated segment could normalize blood flow to its associated muscles. Specifically, this study will explore whether DN at the C5-6 level improves blood flow in the infraspinatus muscle, enhances shoulder range of motion, and influences muscle strength over time. The secondary purpose is to determine whether C5-6 DN will reduce the number of tender points in the muscles supplied by C5-6.