Falls not only present a considerable health threat, but the resulting treatment and loss of working days also place a heavy economic burden on society. Gait instability is a major fall risk factor, particularly in geriatric patients, and walking is one of the most frequent dynamic activities of daily living. To allow preventive strategies to become effective, it is therefore imperative to identify individuals with an unstable gait. Assessment of dynamic stability and gait variability via biomechanical measures of foot kinematics provides a viable option for quantitative evaluation of gait stability, but the ability of these methods to predict falls has generally not been assessed. Although various methods for assessing gait stability exist, their sensitivity and applicability in a clinical setting, as well as their cost-effectiveness, need verification. The objective of this systematic review was therefore to evaluate the sensitivity of biomechanical measures that quantify gait stability among elderly individuals and to evaluate the cost of measurement instrumentation required for application in a clinical setting. To assess gait stability, a comparative effect size (Cohen's d ) analysis of variability and dynamic stability of foot trajectories during level walking was performed on 29 of an initial yield of 9889 articles from four electronic databases. The results of this survey demonstrate that linear variability of temporal measures of swing and stance was most capable of distinguishing between fallers and non-fallers, whereas step width and stride velocity prove more capable of discriminating between old versus young (OY) adults. In addition, while orbital stability measures (Floquet multipliers) applied to gait have been shown to distinguish between both elderly fallers and non-fallers as well as between young and old adults, local stability measures ( λ s) have been able to distinguish between young and old adults. Both linear and nonlinear measures of foot time series during gait seem to hold predictive ability in distinguishing healthy from fall-prone elderly adults. In conclusion, biomechanical measurements offer promise for identifying individuals at risk of falling and can be obtained with relatively low-cost tools. Incorporation of the most promising measures in combined retrospective and prospective studies for understanding fall risk and designing preventive strategies is warranted.

Safe locomotion is a crucial aspect of human daily living that requires well-functioning motor control processes. The human neuromotor control of daily activities such as walking relies on the complex interaction of subcortical and cortical areas. Technical developments in neuroimaging systems allow the quantification of cortical activation during the execution of motor tasks. Functional near-infrared spectroscopy (fNIRS) seems to be a promising tool to monitor motor control processes in cortical areas in freely moving subjects. However, so far, there is no established standardized protocol regarding the application and data processing of fNIRS signals that limits the comparability among studies. Hence, this systematic review aimed to summarize the current knowledge about application and data processing in fNIRS studies dealing with walking or postural tasks. Fifty-six articles of an initial yield of 1420 publications were reviewed and information about methodology, data processing, and findings were extracted. Based on our results, we outline the recommendations with respect to the design and data processing of fNIRS studies. Future perspectives of measuring fNIRS signals in movement science are discussed.

The demographic change in industrial countries, with increasingly sedentary lifestyles, has a negative impact on mental health. Normal and pathological aging leads to cognitive deficits. This development poses major challenges on national health systems. Therefore, it is necessary to develop efficient cognitive enhancement strategies. The combination of regular physical exercise with cognitive stimulation seems especially suited to increase an individual’s cognitive reserve, i.e., his/her resistance to degenerative processes of the brain. Here, we outline insufficiently explored fields in exercise-cognition research and provide a classification approach for different motor-cognitive training regimens. We suggest to classify motor-cognitive training in two categories, (I) sequential motor-cognitive training (the motor and cognitive training are conducted time separated) and (II) simultaneous motor-cognitive training (motor and cognitive training are conducted sequentially). In addition, simultaneous motor-cognitive training may be distinguished based on the specific characteristics of the cognitive task. If successfully solving the cognitive task is not a relevant prerequisite to complete the motor-cognitive task, we would consider this type of training as (IIa) motor-cognitive training with additional cognitive task. In contrast, in ecologically more valid (IIb) motor cognitive training with incorporated cognitive task, the cognitive tasks are a relevant prerequisite to solve the motor-cognitive task. We speculate that incorporating cognitive tasks into motor tasks, rather than separate training of mental and physical functions, is the most promising approach to efficiently enhance cognitive reserve. Further research investigating the influence of motor(-cognitive) exercises with different quantitative and qualitative characteristics on cognitive performance is urgently needed.

Background: Physical exercise has a positive effect on cognitive performance and quality of life (QoL). One reason for this is the upregulation of brain-derived neurotrophic factor, which improves brain plasticity. Intermittent hypoxia promotes first the proliferation of endogenous neuroprogenitors which leads to an increased number of newborn neurons and second the expression of brain-derived neurotrophic factor in the adult hippocampus. Intermittent hypoxia may, therefore, support synaptic plasticity, the process of learning and provoke antidepressant-like effects. Hence, intermittent hypoxia might also lead to improved cognitive functioning and QoL. Objective: This study aims to evaluate to what extent physical activity with preceded intermittent hypoxic training is more effective than solely strength-endurance training on cognitive performance and QoL. Methods: 34 retired people aged between 60 and 70 years were randomly assigned to a control group or intervention group. Contrarily to the control group, which was supplied with a placebo air mixture, the intervention group was supplied with an intermittent hypoxic training prior to a strength-endurance exercise program. The cognitive performance of individuals was examined using the d2 test and the Number Combination Test (ZVT) both before and after the exercise program. We assessed QoL with the Medical Outcomes Study Short-Form 36-Item Health Survey (SF-12) and Pittsburgh Sleep Quality Index (PSQI) and the strength-endurance capacity using the Spring test. Results: Regarding the d2 test, a time × group effect was observed. Speed of cognitive performance in seconds was measured using ZVT. Here, no interaction effect was discovered. An interaction effect was not found in the Physical Component Summary scores (SF-12). Regarding the Mental Component Summary, an interaction effect just failed to become statistically significant. Furthermore, we determined sleep quality with the PSQI. Here, an interaction effect was observed. The analysis of the strength-endurance test revealed no interaction effects. Conclusion: The data of the current study suggest that an additional intermittent hypoxic training combined with physical exercise augments the positive effects of exercise on cognitive performance and QoL in elderly humans.