Biomechanics of ankle giving way:A case report of accidental ankle giving way during the drop landing test

Background:Several case studies observed that the lateral ankle sprain resulted from a sudden increase in ankle inversion accompanied by internal rotation.However,without sufficient ankle kinetics and muscle activity information in the literature,the detailed mechanism of ankle sprain is still unrevealed.The purpose of our case report is to present 2 accidental ankle giving way incidents for participants with chronic ankle instability(CAI)and compare to their normal trials with data of kinematics,kinetics,and electromyography(EMG).Case description:Two young female participants accidentally experienced the ankle giving way when landing on a 25°lateral-tilted force plate.3 D kinematics,kinetics,and muscle activity were recorded for the lower extremity.Qualitative comparisons were made between the giving way trials and normal trials for joint angles,angular velocities,moments,centers of pressure and EMG linear envelopes.Results:One participant’s giving way trial displayed increased ankle inversion and internal rotation angles in the pre-landing phase and at initial contact compared to her normal trials.Another participant’s giving way trial exhibited greater hip abduction angles and delayed activation of the peroneus longus muscle in the pre-landing phase versus her normal trials.Conclusion:A vulnerable ankle position(i.e.,more inverted and internally rotated),and a late activation of peroneus activity in the pre-landing phase could result in the ankle giving way or even sprains.A neutral ankle position and early activation of ankle evertors before landing may be helpful in preventing ankle sprains.

Cross-cultural adaptation and validation of an ankle instability questionnaire for use in Chinese-speaking population

Background:The Identification of Functional Ankle Instability(IdFAI)is a valid and reliable tool to identify chronic ankle instability;however,it was developed in English,thus limiting its usage only to those who can read and write in English.The objectives of our study were to(1)cross-culturally adapt a Chinese(Mandarin)version of the IdFAI and(2)determine the psychometric properties of the Chinese version IdFAI.Methods:The cross-cultural adaptation procedures used by the investigators and translators followed previously published guidelines and included 6 stages:(1)initial translation,(2)synthesis of the translations,(3)back translation,(4)developing the pre-final version for field testing,(5)testing the pre-final version,and(6)finalizing the Chinese version of IdFAI(IdFAI-C).Five psychometric properties of the IdFAI-C were assessed from results of 2 participant groups:bilingual(n=20)and Chinese(n=625).Results:A high degree of agreement was found between the English version of IdFAI and IdFAI-C(intra-class correlation_(2,1)=0.995).An excellent internal consistency(Cronbach'sα=0.89),test—retest reliability(intra-class correlation_(2,1)=0.970),and construct validity(r(625)=0.67)was also found for the IdFAI-C.In addition,the results of exploratory and confirmatory factor analysis indicated that ankle instability was the only construct measured from the IdFAI.Conclusion:The IdFAI-C is a highly reliable and valid self-report questionnaire that can be used to assess ankle instability.Therefore,we suggest that it can be used to effectively and accurately assess chronic ankle instability in clinical settings for Chinese-speaking individuals.