Required friction during overground walking is lower among obese compared to non-obese older men, but does not differ with obesity among women

Weekly minutes of moderate to vigorous physical activity is associated with movement quality in overweight and obese older adults, independent of age

BACKGROUND

Physical activity can improve function and decrease healthcare spending among overweight and obese older adults. Although unstructured physical activity has been related to cardiometabolic improvements, the relationship between unstructured activity and movement quality is unclear.

AIMS

This study aimed to evaluate the association of amount of unstructured free-living moderate-vigorous physical activity (MVPA) with measures of movement quality in overweight and obese older adults.

METHODS

The association of MVPA with movement quality was assessed in 165 overweight and obese older adults (Age: 77.0(8.0) years; Body mass index (BMI): 29.2(5.3) kg/m2). Participants performed overground walking, the Figure of 8 Walk test, and the Five-Times Sit to Stand. Weekly physical activity was measured using a waist-worn Actigraph activity monitor.

RESULTS

Movement quality during straight path [gait speed (ρ = 0.30, p < 0.01), stride length (ρ = 0.33, p < 0.01), double-limb support time (ρ = -0.26, p < 0.01), and gait symmetry (ρ = 0.17, p = 0.02)] and curved path [F8W time (ρ = -0.22, p < 0.01) and steps (ρ = -0.22, p < 0.01)] walking were associated with weekly minutes of MVPA after controlling for age. Five-Times Sit to Stand performance was not significantly associated with weekly minutes of MVPA (ρ = -0.10, p = 0.13).

CONCLUSIONS

Older adults with high BMIs who are less active also demonstrate poorer movement quality, independent of age. Physical activity engagement and task-specific training should be targeted in interventions to promote healthy aging, decrease falls, and delay disability development. Future work should consider the interconnected nature of movement quality with physical activity engagement and investigate if targeting one influences the other.

Approximate Bayesian Techniques for Statistical Model Selection and Quantifying Model Uncertainty-Application to a Gait Study

Frequently, biomedical researchers need to choose between multiple candidate statistical models. Several techniques exist to facilitate statistical model selection including adjusted R², hypothesis testing and p-values, and information criteria among others. One particularly useful approach that has been slow to permeate the biomedical literature is the notion of posterior model probabilities. A major advantage of posterior model probabilities is that they quantify uncertainty in model selection by providing a direct, probabilistic comparison among competing models as to which is the "true" model that generated the observed data. Additionally, posterior model probabilities can be used to compute posterior inclusion probabilities which quantify the probability that individual predictors in a model are associated with the outcome in the context of all models considered given the observed data. Posterior model probabilities are typically derived from Bayesian statistical approaches which require specialized training to implement, but in this paper we describe an easy-to-compute version of posterior model probabilities and inclusion probabilities that rely on the readily-available Bayesian information criterion. We illustrate the utility of posterior model probabilities and inclusion probabilities by re-analyzing data from a published gait study investigating factors that predict required coefficient of friction between the shoe sole and floor while walking.

Gait initiation differences between overweight and normal weight individuals

Accidental falls often occur during gait initiation. Excess body weight has been identified as a risk factor for accidental falls. This study aimed to examine the differences of gait initiation between overweight and normal-weight individuals. Fourteen overweight and 14 normal-weight young adults participated in the study. They were instructed to perform the gait initiation task under single-task and dual-task conditions. Dependent variables for the assessment of gait initiation included spatial-temporal measures and postural stability measures. The results showed that overweight could compromise postural stability during gait initiation, primarily by decreasing margin of stability in the anterior-posterior direction. Cognitive task interference with gait initiation was found to be similar between the overweight and normal weight groups. The findings from the present study can aid in better understanding the mechanisms associated with increased fall risks among overweight individuals. They also highlight the importance of overweight control in fall prevention. Practitioner summary: Overweight was found to compromise postural stability during gait initiation, primarily by decreasing margin of stability in the anterior-posterior direction. The findings highlight the importance of overweight control in fall prevention. Abbreviations: ANOVA: analyses of variance; AP: anterior-posterior; APA: anticipatory postural adjustment; BOS: base of support; BW: Body weight; COM: centre-of-mass; COP: center-of-pressure; CT: cognitive task; GI: Gait initiation; GRF: ground reaction force; HC: heel-contact; HO: heel-off; ML: medial-lateral; MOS: margin of stability; SD: standard deviation; SE: step execution; SL: step length; SW: step width; VEL_COM: velocity of the COM; XCOM: extrapolated center of mass.