In many cases, ankle sprains may seem to be a minor condition, but 50 to 60 percent of individuals experience continued symptoms from the initial injury, mostly associated with lateral ankle sprains, patients are commonly diagnosed as having ankle instability. Chronic ankle instability has been defined as the presence of persistent post-acute symptoms such as occasional swelling, impaired strength, instability, and impaired balance responses for more than 6 months following the initial ankle injury.

Studies showed an inability to complete jumping and landing tasks within 2 weeks of a first-time lateral ankle sprain, poorer dynamic postural control, and lower self-reported function 6 months after a first-time lateral ankle sprain as being predictive of eventual chronic ankle instability. Functional ankle instability can be defined as recurrent ankle sprains or ongoing sensations of the ankle giving way with normal ankle motion and the absence of objective joint laxity. Some studies have reported that manual therapy, including joint mobilization techniques, is effective for the management of ankle instability; however, the quality of these studies is low.
It seems that neuromuscular/proprioceptive interventions are the most appropriate for the treatment of ankle instability, which suggests that the targeted structure for the management of ankle instability is the musculature. Factors that contribute to functional ankle instability include muscle weakness, impaired muscle recruitment patterns, reduced ankle range of motion, balance deficits, and impaired joint proprioception. There is evidence demonstrating that subjects with ankle instability exhibit delayed fibularis muscle reaction time when compared with the contralateral uninvolved limb or a healthy control group. These findings support the potential role of trigger points (TrPs) in the leg musculature in patients with ankle sprain or functional ankle instability.