Studies have shown that measures of gait variability are associated with falling in older adults. However, few studies have measured gait variability in people with Alzheimer disease, despite the high incidence of falls in Alzheimer disease. The purpose of this study was to compare gait variability of community-dwelling older adults with Alzheimer disease and control subjects at various walking speeds. Ten subjects with mild-moderate Alzheimer disease and ten matched control subjects underwent gait analysis using an electronic walkway. Participants were required to walk at self-selected slow, preferred, and fast speeds. Stride length and step width variability were determined using the coefficient of variation. Results showed that stride length variability was significantly greater in the Alzheimer disease group compared with the control group at all speeds. In both groups, increases in walking speed were significantly correlated with decreases in stride length variability. Step width variability was significantly reduced in the Alzheimer disease group compared with the control group at slow speed only. In conclusion, there is an increase in stride length variability in Alzheimer disease at all walking speeds that may contribute to the increased incidence of falls in Alzheimer disease.

Background: Although there is a tendency toward gait normalization after anterior cruciate ligament reconstruction, altered moments about the knee flexion-extension axis have been reported. It is possible that these gait alterations relate to donor site morbidity associated with the graft harvest. Hypothesis: There is a relationship between graft type and external knee moments during walking. Study Design: Controlled laboratory study. Methods: Three groups were compared: 17 patellar tendon anterior cruciate ligament reconstruction patients (mean, 11 months after surgery), 17 hamstring tendon anterior cruciate ligament reconstruction patients (mean, 9.3 months after surgery), and 17 matched controls. A 3-dimensional motion analysis and force plate system was used to determine sagittal plane kinematics and kinetics of the lower limb during comfortable-speed walking. Results: There were significant differences in the moments about the knee that related to graft type. The external knee flexion moment at midstance was significantly smaller than that in the control knees in 65% of patients in the patellar tendon group and 29% of patients in the hamstring tendon group. In contrast, the external knee extension moment at terminal stance was significantly smaller than that in the control knees in 53% of subjects in the hamstring tendon group and 23% of subjects in the patellar tendon group. Conclusions: There are graft-specific differences in knee biomechanics after anterior cruciate ligament reconstruction that appear to relate to the donor site. Clinical Relevance: Considerable debate continues as to whether the patellar tendon or the hamstring tendon graft is preferable for anterior cruciate ligament reconstruction. It is therefore clinically relevant to understand the biomechanical differences in knee function associated with both graft types.