Is consumer behaviour towards footwear predisposing for lower extremity injuries in runners and walkers? : a prospective study

Background: Runners and walkers often suffer from lower extremity injuries. Little is known about the relationship between their consumer behaviour towards footwear and the development of those injuries. Therefore, the aim of this study was to investigate if consumer behaviour towards footwear is a risk factor for lower extremity injuries. Methods: A prospective cohort study was set-up in leisure-time walkers and runners. Potential risk factors in consumer behaviour were obtained by means of a baseline questionnaire related to the acquisition of current walking or running shoes. Information on injuries sustained during a 24 week period after the baseline questionnaire was obtained in 104 runners and 104 walkers using a 2-weekly questionnaire. Binary logistic regression analysis was used to identify risk factors for lower extremity injuries in the consumer behaviour. Results: Forty- nine (24%) subjects suffered a self-reported lower extremity injury. 35 injuries occurred in runners and 14 among walkers. Undergoing a gait analysis before buying shoes was associated with an increased occurrence of lower extremity injuries (odds ratio (OR) 4.76). A protective factor was caring a lot about the right fitting of the shoes (OR 0.11). Conclusion: Runners and walkers should pay attention to the correct size when buying footwear to diminish the risk of lower extremity injury. Buying footwear after a gait analysis increased the risk of a lower extremity injury in runners and walkers, however, this might be associated with the increased risk that was already present because of previous injury

Influence of balance surface on ankle stabilizing muscle activity in subjects with chronic ankle instability

Objective: To evaluate the effect of surface type on muscle activity of ankle stabilizing muscles in subjects with chronic ankle instability. Design: Case controlled, repeated measures study design. Subjects: 28 subjects with chronic ankle instability and 28 healthy controls. Methods: Subjects performed a barefooted single legged stance on uni-axial and multidirectional unstable surfaces. Muscle activity of the mm. peroneus longus/brevis, tibialis anterior, gastrocnemius medialis was registered using surface electromyography. Mixed model analysis was used to explore differences in muscle activity between subjects with chronic ankle instability and controls, and the effect of surface type on muscle activity levels within subjects with chronic ankle instability. Results: No differences were found between subjects with chronic ankle instability and healthy controls. Within subjects with chronic ankle instability, balancing along a frontal axis and on the BOSU evoked overall highest muscle activity level and the firm surface the least. Balancing on the firm surface showed the lowest tibialis anterior/peroneus longus ratio, followed by balancing along a frontal axis and on the Airex pad. Conclusions: Clinicians can use these findings to improve the focus of their balance training program by gradually progressing in difficulty level based on muscle activation levels taking cocontraction ratio’s into account

Reliability and validity of the INFOOT three-dimensional foot digitizer for patients with rheumatoid arthritis

Background: Abnormal foot posture and deformities are identified as important features in rheumatoid arthritis. There is still no consensus regarding the optimum technique(s) for quantifying these features; hence, a foot digitizer might be used as an objective measurement tool. We sought to assess the validity and reliability of the INFOOT digitizer. Methods: To investigate the validity of the INFOOT digitizer compared with clinical measurements, we calculated Pearson correlation coefficients. To investigate the reliability of the INFOOT digitizer, we calculated intraclass correlation coefficients, SEMs, smallest detectable differences, and smallest detectable difference percentages. Results: Most of the 38 parameters showed good intraclass correlation coefficients, with values greater than 0.9 for 30 parameters and greater than 0.8 for seven parameters. The left heel bone angle expressed a moderate correlation, with a value of 0.609. The SEM values varied between 0.31 and 3.51 mm for the length and width measures, between 0.74 and 5.58 mm for the height data, between 0.75 and 5.9 mm for the circumferences, and between 0.78 degrees and 2.98 degrees for the angles. The smallest detectable difference values ranged from 0.86 to 16.36 mm for length, width, height, and circumference measures and from 2.17 degrees to 8.26 degrees for the angle measures. For the validity of the INFOOT three-dimensional foot digitizer, Pearson correlation coefficients varied between 0.750 and 0.997. Conclusions: In this rheumatoid arthritis population, good validity was demonstrated compared with clinical measurements, and most of the obtained parameters proved to be reliable. (J Am Podiatr Med Assoc 101(3): 198-207, 2011

To what extent does body height affect the use and satisfaction of electrically-assisted bicycles for postal purpose?

To investigate to what extent body height affects the use and satisfaction of electrically-assisted bicycles (EB) among postal workers, 1115 EB users filled in a questionnaire and 28 postal workers were observed during their distribution round. We aimed to provide a framework to estimate the possible effects of providing multiple frame sizes to postal workers. Although the body height of postal workers affected how they reached for mail and delivered it, it hardly affected their satisfaction with the current EB. Accessibility of the front carrier seemed to be the main issue that could be coped with by providing different frames. Ironically, postal workers for whom the front carrier was most accessible (tallest group) reported the highest physical load. The relevance of these results with respect to the availability of multiple frame sizes and other changes to the EB that might be beneficial from an ergonomic point of view is discussed

Classification of forefoot plantar pressure distribution in persons with diabetes : a novel perspective for the mechanical management of diabetic foot?

Background: The aim of this study was to identify groups of subjects with similar patterns of forefoot loading and verify if specific groups of patients with diabetes could be isolated from non-diabetics. Methodology/Principal Findings: Ninety-seven patients with diabetes and 33 control participants between 45 and 70 years were prospectively recruited in two Belgian Diabetic Foot Clinics. Barefoot plantar pressure measurements were recorded and subsequently analysed using a semi-automatic total mapping technique. Kmeans cluster analysis was applied on relative regional impulses of six forefoot segments in order to pursue a classification for the control group separately, the diabetic group separately and both groups together. Cluster analysis led to identification of three distinct groups when considering only the control group. For the diabetic group, and the computation considering both groups together, four distinct groups were isolated. Compared to the cluster analysis of the control group an additional forefoot loading pattern was identified. This group comprised diabetic feet only. The relevance of the reported clusters was supported by ANOVA statistics indicating significant differences between different regions of interest and different clusters. Conclusion/s Significance: There seems to emerge a new era in diabetic foot medicine which embraces the classification of diabetic patients according to their biomechanical profile. Classification of the plantar pressure distribution has the potential to provide a means to determine mechanical interventions for the prevention and/or treatment of the diabetic foot