The Association Between Chronic Ankle Instability and Neuromuscular Performance in Pre-Recruitment Infantry Soldiers.

CONTEXT Ankle instability can include various impairments, including perceived instability (PI), mechanical instability (MI), and recurrent sprains (RS), alone or combined. OBJECTIVE To examine the prevalence of eight ankle impairment subgroups and their effect on neuromuscular performance in pre-recruitment combat soldiers. DESIGN Cross-sectional study. SETTING Military Infantry basic training base. PARTICIPANTS A total of 364 pre-recruitment males combat soldiers (aged 18-21). MAIN OUTCOME MEASURES The participants were assessed for PI (via the Cumberland Ankle Instability Tool), MI (using the Anterior Drawer Test and Medial Talar Tilt Test ), and RS (based on history) in their dominant and non-dominant legs; injuries were combined into eight subgroups: (A) PI; (B) RS; (C) PI+RS; (D) MI; (E) PI+MI; (F) MI+RS; (G) PI+MI+RS; and (H) none. Participants were screened for neuromuscular performance (proprioceptive ability, hopping agility, triceps surae muscle strength, and dynamic postural balance) during the first week of military basic training. RESULTS For the dominant and non-dominant leg, RS were reported by 18.4% and 20.5% of the participants, respectively; PI was reported by 27.8% and 29.2%; and MI was seen in 9.9% and 8.8% of the participants, respectively. One-Way ANOVA showed significant differences in the mean proprioceptive ability scores (assessed using the Active Movement Extent Discrimination Apparatus) of all subgroups with impairments in both the dominant and non-dominant leg [F=6.943, η2=.081, p<.001; and, F=7.871, η2=.091, p<.001, respectively]. Finally, significant differences were found in the mean muscle strength of subgroups with impairments in the non-dominant leg [F=4.884, η2=.056, p=.001]. CONCLUSIONS A high prevalence of ankle impairments were identified among the participants, who exhibited reduced abilities in most neuromuscular assessments compared to those without impairments. Moreover, participants with one impairment (either PI, RS, or MI) exhibited different neuromuscular performance deficits than those with more than one impairment.