Improvement in gait stability in older adults after ten sessions of standing balance training

What determines gait speed in community-living older adults? A relative weight analysis

PURPOSE

Slower gait is prevalent in older adults. Multiple factors contribute to the slowness in older adults. However, whether these factors affect gait speed similarly or differently remains unknown. The primary purpose of this study was to explore the relative importance of eight modifiable factors (body mass index, leg muscle strength, power, dorsiflexion range of motion, tactile sensation, balance, fear of falling, and cognition) affecting gait speed in community-living older adults.

METHODS

Eighty-five community-living older adults (mean ± standard deviation age: 72.3 ± 5.5 years; 51 females and 34 males) were enrolled in this cross-sectional study. A motion capture system assessed their gait speed. Those eight factors that could slow gait speed in older adults were also evaluated. A multiple linear regression model and relative weight analysis were utilized to determine the relative importance of each factor in contributing to the gait speed variation.

RESULTS

All eight factors were significantly correlated with the gait speed. Together, they accounted for about 50% of the observed variation in gait speed. Six factors (body mass index, strength, power, range of motion, balance, and fear of falling) each explained a statistically significant portion of the gait speed variation. The most important factor was the leg muscle power (relative weight = 0.124), contributing 25.2% of the explained speed variation.

CONCLUSION

Leg muscle power could be a principal factor determining gait speed in older adults. Other factors also significantly influence gait speed in this population. The findings could guide prioritizing actions to improve gait speed in older individuals.

A Pilot Study on the Influence of Self-Paced Auditory Cues and Preferred Music on Gait in Persons with Parkinson's Disease

Background: Gait disturbance in Parkinson's Disease (PD) significantly impacts quality of life and is not completely mitigated by dopaminergic treatment. Auditory cueing has been shown to help improve certain aspects of gait, but its effects when matched to individuals' preferred walking rate remain unexplored. Methods: Nine individuals with PD walked at their preferred rate across a GAITRite® mat under three separate conditions: self-paced, metronome-cued, and music-cued. Spatiotemporal gait measures were collected and analyzed using repeated measures ANOVAs and post-hoc paired-samples t-tests. Results: A main effect of condition was revealed for step width (F = 3.533, p = 0.054, ηp2 = 0.306), with reduced step width revealed during the music-cued condition. Post-hoc analysis revealed no significance (p > 0.063). Conclusions: The trend in step width data suggests a potential benefit of music cueing for enhancing gait stability in persons with PD. Results of this pilot study provide valuable framework for future research and the development of therapeutic interventions to enhance gait stability, reduce fall risk, and improve overall quality of life.

Dataset of walking and running biomechanics with different step widths across different speeds

The mediolateral distance between both heels at first contact is known as step width, defined as a frontal plane spatial variable. Short-term variations in step width during walking and running may impact the lower-limb biomechanics in all three planes. Considering these features, the proposed dataset of this study was established on 13 healthy young males aged between 20 and 24 years within the normal BMI range, providing data in raw ready for use for the community. In laboratory conditions, participants were required to locomote (walk and run) at six different step widths while walking at a preferred speed, running at 3.0 m/s, and running at 3.7 m/s. This dataset could expand the population sample size of similar relevant datasets and provide the data basis for future exploring on the effect of acute step width changes on the kinematic and kinetic chain in human lower at different movement speeds.

Lower extremity joint kinematics in individuals with and without bilateral knee osteoarthritis during normal and narrow-base walking: A cross-sectional study

BACKGROUND

Knee osteoarthritis (KOA) is a prevalent musculoskeletal disease affecting joint mechanics. Considering the effect of step-width changes on the biomechanics of gait, especially the alteration of stability dynamics during narrow-base gait, this study investigated the kinematic parameters of the lower extremities during both normal and narrow-base walking in individuals with and without KOA.

METHODS

A cross-sectional study with 20 individuals with bilateral KOA and 20 controls was conducted. Participants walked on a treadmill at a preferred speed across normal and narrow paths. Joint angles and angular velocities in the sagittal and frontal planes were recorded, and mixed ANOVA was used to analyze group × condition effects.

RESULTS

Significant main effects of walking condition were observed for hip (p = 0.001) and ankle angles (p = 0.002) in the frontal plane, and knee (p = 0.004) and ankle angular velocities (p = 0.002) in the sagittal plane. Moreover, there were significant main effects of group on the hip (p = 0.01) and knee angles (p = 0.04) in the sagittal plane. KOA group showed higher peak hip adduction (p < 0.001) and ankle inversion (p = 0.02]) during narrow-base walking than on the normal path. People with KOA had also significantly higher peak angular velocity of knee flexion (p = 0.03), ankle dorsiflexion (p = 0.002), and ankle inversion (p = 0.03) during narrow-base walking.

CONCLUSIONS

The findings suggest that KOA and narrow-base gait challenges may trigger distinct kinematic adaptation strategies, potentially contributing to cartilage degeneration and altering balance mechanisms.

What are the hidden shortcomings of balance training research in older adults that prevent its transfer into practice? Scoping review

BACKGROUND

Although a lot of attention is paid to the flaws of balance training research in older adults, the low methodological quality and incomplete reporting of studies still limit the knowledge transfer between research and practice. These known shortcomings are considered also as barriers for creating recommendations for balance training in older adults. Despite the considerable efforts to improve the scientific quality of studies, such recommendations have not yet been formulated to date. Therefore, this scoping review aims (1) to analyze the literature that addresses balance training in older adults, (2) to identify and summarize gaps in the existing literature, and (3) to propose future research on this topic.

METHODS

We focused on studies that evaluated the effect of balance training on balance control in apparently healthy older adults over 60 years of age.

RESULTS

Out of 6910 potentially relevant studies, only 26 met the eligibility criteria. The identified shortcomings were as follows: missing a priori criteria for training session attendance and leisure-time physical activities, insufficiently described exercises and training load, and inappropriately chosen tests.

CONCLUSIONS

Among the shortcomings of the balance training research, the insufficiently described balance training program and inappropriately chosen tests can be considered the most important. For this reason, even with an excellently designed experiment, it is almost impossible for practitioners to apply the results of such studies into practice. Therefore, researchers should pay more attention to possible users of the acquired knowledge, which is more than desirable in the case of exercise programs for older adults.

Effects of Stroboscopic Goggles on Standing Balance in the Spatiotemporal and Frequency Domains: An Exploratory Study

Balance training paradigms have been shown to effectively reduce fall risk. Visual feedback is an important sensory mechanism for regulating postural control, promoting visual perturbations for balance training paradigms. Stroboscopic goggles, which oscillate from transparent to opaque, are a form of visual perturbation, but their effect on standing balance has not been assessed. In this study, 29 participants stood in bilateral and tandem stances as the center of pressure was recorded for 6 consecutive minutes wherein there were no stroboscopic perturbations in the first and last minutes. Spatial-temporal, frequency domain, and nonlinear standing balance parameters were calculated for each period. More differences in spatial-temporal parameters due to the strobe were found in the medial-lateral direction than the anterior-posterior direction. More differences in frequency domain parameters were observed in the anterior-posterior direction than the medial-lateral direction, but this did not occur for each variable. The nonlinear parameters were strongly affected by the strobe. Stroboscopic perturbations did not affect the bilateral and tandem stances equally. Spatial-temporal parameters for the tandem stance were greater in magnitude during the strobe period than the no strobe periods. This effect was not seen with the bilateral stance. This indicates that the efficacy of stroboscopic perturbations for challenging standing balance depends on task difficulty. Balance training paradigms that utilize stroboscopic perturbations will need to harmonize these perturbations with task difficulty.

Balance training in older adults enhances feedback control after perturbations

Background

As we age, avoiding falls becomes increasingly challenging. While balance training can mitigate such challenges, the specific mechanisms through which balance control improves remains unclear.

Methods

We investigated the impact of balance training in older adults on feedback control after perturbations, focusing on kinematic balance recovery strategies and muscle synergy activation. Twenty older adults aged over 65 underwent short-term (one session) and long-term (3-weeks, 10 sessions) balance training, and their recovery from unpredictable mediolateral perturbations was assessed. Perturbations consisted of 8° rotations of a robot-controlled platform on which participants were balancing on one leg. We measured full-body 3D kinematics and activation of 15 leg and trunk muscles, from which linear and rotational kinematic balance recovery responses and muscle synergies were obtained.

Results

Our findings revealed improved balance performance after long-term training, characterized by reduced centre of mass acceleration and (rate of change of) angular momentum. Particularly during the later stage of balance recovery the use of angular momentum to correct centre of mass displacement was reduced after training, decreasing the overshoot in body orientation. Instead, more ankle torque was used to correct centre of mass displacement, but only for perturbations in medial direction. These situation and strategy specific changes indicate adaptations in feedback control. Activation of muscle synergies during balance recovery was also affected by training, specifically the synergies responsible for leg stiffness and ankle torques. Training effects on angular momentum and the leg stiffness synergy were already evident after short-term training.

Conclusion

We conclude that balance training in older adults refines feedback control through the tuning of control strategies, ultimately enhancing the ability to recover balance.

Sensor-Based Gait and Balance Assessment in Healthy Adults: Analysis of Short-Term Training and Sensor Placement Effects

While the analysis of gait and balance can be an important indicator of age- or disease-related changes, it remains unclear if repeated performance of gait and balance tests in healthy adults leads to habituation effects, if short-term gait and balance training can improve gait and balance performance, and whether the placement of wearable sensors influences the measurement accuracy. Healthy adults were assessed before and after performing weekly gait and balance tests over three weeks by using a force plate, motion capturing system and smartphone. The intervention group (n = 25) additionally received a home-based gait and balance training plan. Another sample of healthy adults (n = 32) was assessed once to analyze the impact of sensor placement (lower back vs. lower abdomen) on gait and balance analysis. Both the control and intervention group exhibited improvements in gait/stance. However, the trends over time were similar for both groups, suggesting that targeted training and repeated task performance equally contributed to the improvement of the measured variables. Since no significant differences were found in sensor placement, we suggest that a smartphone used as a wearable sensor could be worn both on the lower abdomen and the lower back in gait and balance analyses.

The Biomechanical Influence of Step Width on Typical Locomotor Activities: A Systematic Review

BACKGROUND

Step width is a spatial variable in the frontal plane, defined as the mediolateral distance between the heel (forefoot during sprinting) of bilateral feet at initial contact. Variations in step width may impact the lower limb biomechanics. This systematic review aimed to synthesize the published findings to determine the influence of acute changes in step width on locomotion biomechanics and provide implications for injury prevention and enhanced sports performance.

METHODS

Literature was identified, selected, and appraised in accordance with the methods of a systematic review. Four electronic databases (Web of Science, MEDLINE via PubMed, Scopus, and ScienceDirect) were searched up until May 2023 with the development of inclusion criteria based on the PICO model. Study quality was assessed using the Downs and Black checklist and the measured parameters were summarized.

RESULTS

Twenty-three articles and 399 participants were included in the systematic review. The average quality score of the 23 studies included was 9.39 (out of 14). Step width changed the kinematics and kinetics in the sagittal, frontal, and transverse planes of the lower limb, such as peak rearfoot eversion angle and moment, peak hip adduction angle and moment, knee flexion moment, peak knee internal rotation angle, as well as knee external rotation moment. Alteration of step width has the potential to change the stability and posture during locomotion, and evidence exists for the immediate biomechanical effects of variations in step width to alter proximal kinematics and cues to impact loading variables.

CONCLUSION

Short-term changes in step width during walking, running, and sprinting influenced multiple lower extremity biomechanics. Narrower step width may result in poor balance and higher impact loading on the lower extremities during walking and running and may limit an athlete's sprint performance. Increasing step width may be beneficial for injury rehabilitation, i.e., for patients with patellofemoral pain syndrome, iliotibial band syndrome or tibial bone stress injury. Wider steps increase the supporting base and typically enhance balance control, which in turn could reduce the risks of falling during daily activities. Altering the step width is thus proposed as a simple and non-invasive treatment method in clinical practice.

Time-course of balance training-related changes on static and dynamic balance performance in healthy children

OBJECTIVE

In healthy children, there is evidence of improvements in static and dynamic balance performance following balance training. However, the time-course of balance training-related changes is unknown. Thus, we determined the effects of balance training after one, three, and six weeks of exercise on measures of static and dynamic balance in healthy children (N = 44, 20 females, mean age: 9.6 ± 0.5 years, age range: 9-11 years).

RESULTS

Participants in the intervention group (2 × 25 min balance exercises per week) compared to those in the control group (2 × 25 min track and field exercises and soccer practice per week) significantly improved their static (i.e., by measuring stance time in the One-Legged Stance test) and dynamic (i.e., by counting step number in the 3-m Beam Walking Backward test) balance performance. Late effects (after 6 weeks) occurred most frequently followed by mid-term effects (after 3 weeks) and then early effects (after 1 week). These findings imply that balance training is effective to improve static and dynamic measures of balance in healthy children, whereby the effectiveness increases with increasing training period.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN16518737 (retrospectively registered at 24th August, 2023).

Age-related modifications of muscle synergies during daily-living tasks: A scoping review

BACKGROUND

Aging is associated with changes in neuromuscular control that can lead to difficulties in performing daily living tasks. Muscle synergy analysis allows the assessment of neuromuscular control strategies and functional deficits. However, the age-related changes of muscle synergies during functional tasks are scattered throughout the literature. This review aimed to synthesize the existing literature on muscle synergies in elderly people during daily-living tasks and examine how they differ from those exhibited by young adults.

METHODS

The Medline, CINAHL and Web of Science databases were searched. Studies were included if they focused on muscle synergies in elderly people during walking, sit-to-stand or stair ascent, and if muscle synergies were obtained by a matrix factorization algorithm.

FINDINGS

Seventeen studies were included after the screening process. The muscle synergies of 295 elderly people and 182 young adults were reported, including 5 to 16 muscles per leg, or leg and trunk. Results suggest that: 1) elderly people and young adults retain similar muscle synergies' number, 2) elderly people have higher muscles weighting during walking, and 3) an increased inter and intra-subject temporal activation variability during specific tasks (i.e., walking and stair ascent, respectively) was reported in elderly people compared to young adults.

INTERPRETATION

This review gives a comprehensive understanding of age-related changes in neuromuscular control during daily living tasks. Our findings suggested that although the number of synergies remains similar, metrics such as spatial and temporal structures of synergies are more suitable to identify neuromuscular control deficits between young adults and elderly people.

Early sleep after action observation plus motor imagery improves gait and balance abilities in older adults

Action observation plus motor imagery (AOMI) is a rehabilitative approach to improve gait and balance performance. However, limited benefits have been reported in older adults. Early sleep after motor practice represents a strategy to enhance the consolidation of trained skills. Here, we investigated the effects of AOMI followed by early sleep on gait and balance performance in older adults. Forty-five older adults (mean age: 70.4 ± 5.2 years) were randomized into three groups performing a 3-week training. Specifically, AOMI-sleep and AOMI-control groups underwent observation and motor imagery of gait and balance tasks between 8:00 and 10:00 p.m. or between 8:00 and 10:00 a.m. respectively, whereas Control group observed landscape video-clips. Participants were assessed for gait performance, static and dynamic balance and fear of falling before and after training and at 1-month follow-up. The results revealed that early sleep after AOMI training sessions improved gait and balance abilities in older adults compared to AOMI-control and Control groups. Furthermore, these benefits were retained at 1-month after the training end. These findings suggested that early sleep after AOMI may represent a safe and easy-applicable intervention to minimize the functional decay in older adults.

Risk Factors Associated with Falls in Hospitalized Older Adults Patients

Background: Given the complexity of existing assessment methods and the scarcity of specialized geriatric healthcare professionals in China, this study aimed to investigate the risk factors for falls in hospitalized older adults patients. Methods: From July 2018 to July 2020, 112 older adults patients hospitalized in the Department of Geriatrics of our hospital were enrolled and grouped into the low-(n = 12), medium-(n = 58), and high-(n = 42) (fall) risk groups according to the Johns Hopkins Fall Risk Assessment. The patient's clinical characteristics, smoking, alcohol consumption, disease, falling history, osteoporosis medication, mobility, Barthel index, MMSE, and JHFRAT score were compared between groups. Results: The high-risk group had the oldest age, and the lowest weight, BMI, as well as highest rate of stroke history and sarcopenia among the three groups. Multivariate linear regression analysis revealed that stroke history (B = 2.66, 95% CI = [0.43, 4.89]; p = .020) and gait speed (B = -4.78, 95% CI = [-8.74, -0.76]; p = .020) were the significant factors associated with fall risk in hospitalized older adults patients. Conclusions: The results suggested that hospitalized older adults patients with stroke history and low gait speed had higher fall risk. These findings may be helpful for fall prevention in hospitalized older adults patients.

Acute Effect of Single-Session Cerebellar Anodal Transcranial Direct Current Stimulation on Static and Dynamic Balance in Healthy Volunteers

Several studies have shown the positive effect of cerebellar transcranial direct current stimulation (ctDCS) on balance in patients and older adults. However, in healthy volunteers, the results are conflicting. We aimed to investigate the immediate effect of anodal ctDCS on the dynamic-static balance in healthy, non-athletic young adults due to the possible benefits for sports performance. Twenty-one healthy volunteers participated in two consecutive 20 min sessions of ctDCS (2 mA current intensity), with 1-week intervals (anodal ctDCS-sham ctDCS). Flamingo and Y-Balance tests were used to evaluate the static and dynamic balances before and after the ctDCS. A Continuous Performance Test (CPT) was used to evaluate the changes in sustained attention, impulsivity, and vigilance. A repeated measure analysis of variance (ANOVA) was used to compare the changes in balance scores, reaction time, omission, and commission numbers. There were no statistically significant differences in dynamic and static balance scores and in CPT parameters between conditions. In conclusion, there was no immediate neuromodulation effect of anodal ctDCS to improve balance performance in healthy, young individuals. Furthermore, no evidence was found to support the use of cerebellar tDCS to improve sports performance.

The Effects of 12-Week Dual-Task Physical-Cognitive Training on Gait, Balance, Lower Extremity Muscle Strength, and Cognition in Older Adult Women: A Randomized Study

This study aims to investigate the effects of dual-task physical-cognitive the training on body balance (BB), gait performance (GP), lower limb muscle strength (LEMS), and cognitive performance (CP) in a group of cognitively normal older adult women (n = 44; 66.20 ± 4.05 years). Of these, 22 were randomly allocated to the dual-task training (DT) group, and 22 participated in the control group (CG). Assessments were performed at baseline, after 12 weeks of intervention, and at the end of 12 weeks of follow-up, using the following instruments: Timed Up & Go (TUG), Timed Up & Go manual (TUGm), Timed Up & Go cognitive (TUGc), Balance Test (TEC), sit-to-stand test (STS), and verbal fluency test (VF). After 12 weeks of DT training, participants showed a significant time × group interaction in all motor assessments (BB, GP, LEMS), as well as in three cognitive tests (VF-grouping, VF-exchange, VF-total). No time-group interaction effect was indicated for the VF-category test. At all evaluation times, CG members maintained constant physical and cognitive performance. We conclude that 12 weeks of physical-cognitive DT training was effective in promoting BB, GP, and LEMS, as well as CP in cognitively normal older adult women, with lasting effects up to 12 weeks after the intervention.

Revisiting the use of Hoffmann reflex in motor control research on humans

Research in movement science aims at unravelling mechanisms and designing methods for restoring and maximizing human functional capacity, and many techniques provide access to neural adjustments (acute changes) or long-term adaptations (chronic changes) underlying changes in movement capabilities. First described by Paul Hoffmann over a century ago, when an electrical stimulus is applied to a peripheral nerve, this causes action potentials in afferent axons, primarily the Ia afferents of the muscle spindles, which recruit homonymous motor neurons, thereby causing an electromyographic response known as the Hoffmann (H) reflex. This technique is a valuable tool in the study of the neuromuscular function in humans and has provided relevant information in the neural control of movement. The large use of the H reflex in motor control research on humans relies in part to its relative simplicity. However, such simplicity masks subtleties that require rigorous experimental protocols and careful data interpretation. After highlighting basic properties and methodological aspects that should be considered for the correct use of the H-reflex technique, this brief narrative review discusses the purpose of the H reflex and emphasizes its use as a tool to assess the effectiveness of Ia afferents in discharging motor neurones. The review also aims to reconsider the link between H-reflex modulation and Ia presynaptic inhibition, the use of the H-reflex technique in motor control studies, and the effects of ageing. These aspects are summarized as recommendations for the use of the H reflex in motor control research on humans.

Effects of Motor-Cognitive Dual-Task Standing Balance Exergaming Training on Healthy Older Adults' Standing Balance and Walking Performance

Objective: This study examined the effects of motor-cognitive dual-task exergaming standing balance training on healthy older adults' static, dynamic, and walking balance. Methods: Twenty-four adults older than 70 years (control group: n = 9, males = 6, balance training group: n = 15, males = 8) completed the experiment. Dual-tasking standing balance training comprised the accurate control of a ping-pong ball on a tray held with both hands, while standing on one leg (analog training) and three modules of Wii Fit™ exergaming (digital training). The duration of balance training was ∼15 minutes per day, 2 days per week for 8 weeks, in total 16 sessions. We measured one-leg standing time, functional reach distance, walking balance evaluated by the distance walked on a narrow beam (4-cm long, 4-cm wide, and 2-cm high) with single and dual tasking, habitual and maximal walking speed, and muscle strength of the hip extensor, hip abductor, hip adductor, knee extensor, and plantarflexor muscle groups in the right leg at baseline and after 8 weeks. Results: Control group decreased, but balance training group increased one-leg standing time. Only the balance training group improved functional reach distance and hip and knee extensor strength. There was no change in walking speed and walking balance in either group. In the balance training group, changes in maximal speed correlated with changes in dual-tasking walking balance and changes in one-leg standing time correlated with changes in single-tasking walking balance. Conclusion: These results suggest that 16 sessions of motor-cognitive dual-task standing exergaming balance training substantially improved healthy older adults' static and dynamic balance and leg muscle strength but failed to improve walking speed and walking balance. Balance exercises specific to walking balance need to be included in balance training to improve walking balance.