Walking Biomechanics and Energetics of Individuals with a Visual Impairment: A Preliminary Report

Purpose. Although walking gait in sighted populations is well researched, few studies have investigated persons with visual impairments (VIs). Given the lack of physical activity in people with VIs, it is possible that reduced efficiency in walking could adversely affect activity. The purposes of this preliminary study were to (1) examine the biomechanics and energetics utilized during independent and guided walking in subjects with VIs, and (2) compare gait biomechanics between people with VIs and sighted controls. Methods. Three-dimensional motion capture and force platforms were used during independent and guided walking at self-selected speeds. Joint angles, moments, external work, and recovery were compared. Results. The VI group performed independent walking slower and with reduced stride lengths compared with guided walking and sighted controls. Hip range of motion and peak joint moments were reduced during independent walking in the VI group compared with guided walking and controls. Work was greater by 114%, 32%, and 16% in the VI group during independent than during guided walking. Recovery was 11% greater in guided vs. independent walking. Conclusions. In the presented preliminary study among 3 persons with congenital VIs, independent walking was a less efficient mode of walking compared with guided walking and that of sighted controls

A Normative Database of Hip and Knee Joint Biomechanics During Dynamic Tasks Using Four Functional Methods With Three Functional Calibration Tasks

Abstract Although predicted hip joint center (HJC) locations are known to vary widely between functional methods, no previous investigation has detailed functional method-dependent hip and knee biomechanics. The purpose of this study was to define a normative database of hip joint biomechanics during dynamic movements based upon functional HJC methods and calibration tasks. Thirty healthy young adults performed arc, star arc, and two-sided calibration tasks. Motion capture and ground reaction forces were collected during walking, running, and single-leg landings (SLLs). Two sphere-fit (geometric and algebraic) and two coordinate transformation techniques were implemented using each calibration (12 total method–calibration combinations). Surprisingly, the geometric fit-two-sided model placed the HJC at the midline of the pelvis and above the iliac spines, and thus was removed from analyses. A database of triplanar hip and knee kinematics and hip moments and powers was constructed using the mean of all subjects for the eleven method–calibration combinations. A nested analysis of variance approach compared calibration [method] peak hip kinematics and kinetics. Most method differences existed between geometric fit and coordinate transformations (58 of 84 total). No arc-star arc differences were found. Thirty-two differences were found between the two-sided and arc/star arc calibrations. This database of functional method based hip and knee biomechanics serves as an important reference point for interstudy comparisons. Overall, this study illustrates that functional HJC method can dramatically impact hip biomechanics and should be explicitly detailed in future work.</jats:p