BioFoot in-shoe system: Normal values and assessment of the reliability and repeatability

BackgroundBioFoot^® is an in-shoe system to measure plantar pressures at the interface between the shoe and the sole of the foot. Since reliability and good repeatability are necessary to ensure the consistency of measurements on which clinical judgements are based, the aim of the study was to assess the reliability and repeatability of the BioFoot^® system and identify normal values for healthy subjects.Materials and methodsThirty subjects, 18 women and 12 men, were measured twice, with a 7–10 day interval between the sessions, wearing the same kind of shoes. In each session, three trials were recorded. The foot was divided into ten areas: heel, midfoot, whole forefoot, 1st–5th metatarsal heads, hallux, and lesser toes.ResultsThe intra-class correlation coefficients were between 0.76 and 0.96 for all four variables evaluated. The coefficient of variation between two sessions was around 7% (range: 4.6–9%). The mean contact time was 0.81 s, and walking cadence was 101.5 steps per minute. The pressure measurements showed the greatest peak and mean pressures under the second metatarsal head, and the second peak and mean pressures under the third metatarsal head.ConclusionThe plantar pressure measurements showed good to excellent consistency, and it was concluded that the BioFoot^® in-shoe system has good reliability and is repeatable. The highest values were found beneath the forefoot, which is consistent with the literature.