Reliability of a Multisegment Foot Model in Shod Running

Abstract

The purpose of this study was to determine kinematic and marker placement reliability of the Leardini multisegment foot model (LMFM) for tracking foot kinematics during barefoot and shod running without alteration of footwear. Eleven participants, five males (25.6±5 yrs, 73±15.8 kg, 1.75±0.05m) and six females (22.5±2.9 yrs, 66.6±7.2 kg, 1.71±0.05 m) granted institutionally approved written consent to participate. Three-dimensional motion capture (10 Vicon T40-S cameras) was used to capture kinematic data at 200Hz. Kinetic data was captured with an in-ground force platform (Kistler Instruments AG, Switzerland Model 9281B 60x40cm, 2000Hz). Participants were instructed to run at 3.5m/s ±5%. Velocity was monitored with the use of two photoelectric timing gates on either side of the force platform along the running pathway. The running pathway was 15m long, with the force platform placed midway through the path. Acceptable trials occurred when the subject’s foot made contact only with the platform and not with the ground adjacent and velocity was 3.5m/s ±5%. Twenty-four 14mm markers were placed over specific anatomical landmarks of the right lower leg and foot/shoe following the guidelines of the Leardini multisegment foot model. Subjects completed 10 trials while wearing the experimental shoes (New Balance M680 – men’s, and W680 – women’s) as well as 10 trials while barefoot. Participants completed two separate days of testing with identical testing procedures; testing days were separated by at least one day. Conditions were counterbalanced between testing days. Data analysis included the stance phase kinematics reliability testing (ICC 2,1 > 0.7) and marker placement reliability (marker placement difference 0.7 ). Kinematic range of motion at each foot segment (rearfoot, midfoot, and forefoot) across the stance phase were normalized to 101 data points and used for reliability testing. Intersegment ICC values for leg-rearfoot, rearfoot-midfoot, and midfoot-forefoot in three planes were reported. Barefoot and shod reliability values were analyzed and compared separately. Marker placement repeatability, determined as Euclidian distance of markers from rearfoot segment joint center, and standard error of measurement (SEM) were also reported (Bishop, Thewlis, Uden, Ogilvie, & Paul, 2011). Discrete-event kinematic variables were included in analysis: angle at heel-contact, toe-off, maximum value, and total range of motion for all segments in three planes (Deschamps et al., 2011). ICC values for both conditions and all segments and rotations were deemed reliable except for shod, forefoot transverse plane. All markers were placed with excellent repeatability save for shod medial malleolus. The combination of reliable ICC values at all but one segment and plane, coupled with good marker placement repeatability, suggests that the Leardini multisegment foot model can be applied reliably during shod running without alteration of footwear.