Ankle motor strategy use in older and younger adults as assessed by a two-dimensional kinematic analysis smart device application

Abstract

Background/aims Motor strategies change with age, resulting in balance deficits. Clinical options for objectively measuring motor strategies are limited. The use of two-dimensional kinematic analysis through smart devices and applications may provide a cost-effective portable solution for measuring differences in motor strategy use between older and younger adults. The aims of this study were to investigate the concurrent validity of a two-dimensional software and two-dimensional application and to determine whether the application could capture the difference in ankle motor strategy use by older and younger adults (construct validity). Methods Video clips captured by Sony and iPad Air cameras were used to assess concurrent validity between the two-dimensional software and application. A total of 30 older (72.6 ± 4.0 years) and 30 younger (26.5±4.5 years) adults performed forward and backward stepping. A two-dimensional applicationmeasured the ankle position in degrees and time taken in seconds to initiate and complete a compensatory step. Results The two-dimensional software and app demonstrated excellent reliability (ICC2,1 ≥0.994). The ankle forward stop angle differed significantly between older and younger adults (P=0.012). No differences were observed in time taken to initiate and complete a compensatory step. Conclusions The two-dimensional application appears to be a valid alternative to two-dimensional software for measuring ankle motor strategies. Further investigation for clinical use is warranted.