scholarly journals Type II muscle fibre properties are not associated with balance recovery following large perturbations during walking in young and older adults

2021 ◽  
Author(s):  
Christopher McCrum ◽  
Lotte Grevendonk ◽  
Gert Schaart ◽  
Esther Moonen-Kornips ◽  
Johanna A Jörgensen ◽  
...  
Keyword(s):  
Older Adults ◽  
Muscle Strength ◽  
Muscle Fibre ◽  
Balance Control ◽  
Type Ii ◽  
Fibre Type Composition ◽  
Fibre Properties ◽  
Tissue Properties ◽  
Reactive Balance ◽  
Fibre Characteristics

Falls among older adults are often attributed to declining muscle strength with ageing. Associations between muscle strength and balance control have been reported, but the evidence for, and key mechanisms of resistance exercise in fall prevention are unclear. No studies have directly examined the relationship between muscle fibre characteristics and reactive balance control. Here, we address whether or not Type II muscle fibre characteristics associate with reactive balance during walking in young and older adults with varying muscle fibre type composition. We analyse muscle biopsy-derived fibre characteristics and stability during a treadmill-based walking perturbation (trip-like) task of healthy young adults, healthy, normally active older adults, trained older adults and physically impaired older adults. We find no significant associations between Type II muscle fibre properties and reactive balance during walking, indicating that practitioners and researchers should consider more than just the muscle tissue properties when assessing and intervening on fall risk.

scholarly journals Cortical Engagement Metrics During Reactive Balance Are Associated With Distinct Aspects of Balance Behavior in Older Adults

2021 ◽  
Vol 13 ◽  
Author(s):  
Jacqueline A. Palmer ◽  
Aiden M. Payne ◽  
Lena H. Ting ◽  
Michael R. Borich
Keyword(s):  
Older Adults ◽  
Balance Control ◽  
Network Activity ◽  
Beta Activity ◽  
Balance Function ◽  
Potential Biomarker ◽  
Beta Power ◽  
Wide Range ◽  
Motor Cortical ◽  
Reactive Balance

Heightened reliance on the cerebral cortex for postural stability with aging is well-known, yet the cortical mechanisms for balance control, particularly in relation to balance function, remain unclear. Here we aimed to investigate motor cortical activity in relation to the level of balance challenge presented during reactive balance recovery and identify circuit-specific interactions between motor cortex and prefrontal or somatosensory regions in relation to metrics of balance function that predict fall risk. Using electroencephalography, we assessed motor cortical beta power, and beta coherence during balance reactions to perturbations in older adults. We found that individuals with greater motor cortical beta power evoked following standing balance perturbations demonstrated lower general clinical balance function. Individual older adults demonstrated a wide range of cortical responses during balance reactions at the same perturbation magnitude, showing no group-level change in prefrontal- or somatosensory-motor coherence in response to perturbations. However, older adults with the highest prefrontal-motor coherence during the post-perturbation, but not pre-perturbation, period showed greater cognitive dual-task interference (DTI) and elicited stepping reactions at lower perturbation magnitudes. Our results support motor cortical beta activity as a potential biomarker for individual level of balance challenge and implicate prefrontal-motor cortical networks in distinct aspects of balance control involving response inhibition of reactive stepping in older adults. Cortical network activity during balance may provide a neural target for precision-medicine efforts aimed at fall prevention with aging.

Reactive balance control in older adults with diabetes

2018 ◽  
Vol 61 ◽  
pp. 67-72 ◽  
Author(s):  
Pei-Yun Lee ◽  
Yi-Ju Tsai ◽  
Yu-Ting Liao ◽  
Yi-Ching Yang ◽  
Fen-Hwa Lu ◽  
...  
Keyword(s):  
Older Adults ◽  
Balance Control ◽  
Reactive Balance

scholarly journals Associations between lower limb isometric torque, isokinetic torque, and explosive force with phases of reactive stepping in young, healthy adults

2021 ◽  
Author(s):  
Tyler M. Saumur ◽  
Jacqueline Nestico ◽  
George Mochizuki ◽  
Stephen D. Perry ◽  
Avril Mansfield ◽  
...  
Keyword(s):  
Muscle Strength ◽  
Lower Limb ◽  
Balance Control ◽  
Healthy Adults ◽  
Explosive Force ◽  
Isokinetic Torque ◽  
Isometric Torque ◽  
The Relationship ◽  
Reactive Balance ◽  
Reactive Stepping

AbstractReactive stepping is one of the only strategies that can lead to successful stabilization following a large challenge to balance. Improving function of specific muscles associated with reactive stepping may improve features of reactive balance control. Accordingly, this study aimed to determine the relationship between lower limb muscle strength and explosive force with force plate-derived timing measures of reactive stepping. Nineteen young, healthy adults (27.6 ± 3.0 years of age; 10 women: 9 men) responded to 6 perturbations (~13-15% of body weight) using an anterior lean-and-release system (causing a forward fall), where they were instructed to recover balance in as few steps as possible. Foot-off, swing, and restabilization times were estimated from force plates. Peak isokinetic torque, isometric torque, and explosive force of the knee extensors/flexors and plantar/dorsiflexors were measured using isokinetic dynamometry. Correlations were run based on a priori hypotheses and corrected for the number of comparisons (Bonferroni) for each variable. Knee extensor explosive force was negatively correlated with swing time (r = −0.582, p = 0.009). Knee flexor peak isometric torque also showed a negative association with restabilization time (r = −0.459, p = 0.048), however this was not statistically significant after correcting for multiple comparisons. There was no significant relationship between foot-off time and knee or plantar flexor explosive force (p > 0.025). These findings suggest that there may be utility to identifying specific aspects of reactive step timing when studying the relationship between muscle strength and reactive balance control. Exercise training aimed at improving falls risk should consider targeting specific aspects of muscle strength depending on specific deficits in reactive stepping.

scholarly journals Perturbation-based balance assessment: Examining reactive balance control in older adults with mild cognitive impairments

2021 ◽  
Author(s):  
Lakshmi N Kannan ◽  
Tanvi S Bhatt
Keyword(s):  
Older Adults ◽  
Young Adults ◽  
Cognitive Impairment ◽  
Mild Cognitive Impairment ◽  
Balance Control ◽  
Step Length ◽  
Subjective Memory ◽  
Step Initiation ◽  
Risk Of Falls ◽  
Reactive Balance

Abstract Background Older adults with mild cognitive impairment (OAwMCI) present subtle balance and gait deficits along with subjective memory decline. Although these presentations might not affect activities of daily living (ADLs), they attribute to a two-folded increase in falls. While changes occurring in volitional balance control during ADLs have been extensively examined among OAwMCI, reactive balance control, required to recover from external perturbations, has received little attention. Therefore, this study examined reactive balance control in OAwMCI compared to their healthy counterparts. Methods Fifteen older adults with mild cognitive impairment (OAwMCI), fifteen cognitively intact older adults (CIOA) (>55 years), and fifteen young adults (18–30 years) were exposed to stance perturbations at three different intensities. Behavioral outcomes postural COM state stability, step length, step initiation, and step execution were computed. Results Postural COM state stability was the lowest in OAwMCI compared to CIOA and young adults, and it deteriorated at higher perturbation intensities (P < 0.001). Step length was the lowest among OAwMCI and was significantly different from young adults (P < 0.001) but not from CIOA. Unlike OAwMCI, CIOA and young adults increased their step length at higher perturbation intensities (P < 0.001). OAwMCI showed longer recovery step initiation times and shorter execution times compared to CIOA and young adults at higher perturbation intensities (P < 0.001). Conclusion OAwMCI exhibit exacerbated reactive instability and are unable to modulate their responses as the threat to balance control altered. Thus, they are at a significantly higher risk of falls than their healthy counterparts.

Relaxation Rate of Constituent Muscle-Fibre Types in Human Quadriceps

1979 ◽  
Vol 56 (1) ◽  
pp. 47-52 ◽  
Author(s):  
C. M. Wiles ◽  
A. Young ◽  
D. A. Jones ◽  
R. H. T. Edwards
Keyword(s):  
Relaxation Rate ◽  
Muscle Fibre ◽  
Human Subjects ◽  
Muscle Fibre Types ◽  
Muscle Fibres ◽  
Isometric Contractions ◽  
Type I ◽  
Type Ii ◽  
Fibre Type Composition

1. Muscle fibres may be subdivided into type I (with slow-twitch contractile properties) and type II (fast-twitch) depending on their myosin adenosine triphosphatase activity. In voluntary isometric contractions type I fibres are utilized at low forces (<20% of maximum) whereas type II fibres are recruited in addition at high forces. This physiological recruitment order has enabled us to measure the relaxation rate of type I and II fibres in vivo in normal human subjects. 2. Relaxation rate was measured in 16 subjects from low (10% of maximum) and maximum isometric quadriceps contractions and the muscle-fibre type composition determined from needle-biopsy specimens in 10 subjects. The relaxation rate of type II fibres was calculated to be twice as fast as that of type I. 3. It was not possible to estimate, from studies in 33 quadriceps muscles (25 normal subjects), the contribution of type II fibres to overall fibre area from the relaxation rate as determined from electrically stimulated isometric contractions.

scholarly journals Determining the optimal dose of reactive balance training after stroke: study protocol for a pilot randomised controlled trial

BMJ Open ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. e038073
Author(s):  
Avril Mansfield ◽  
Elizabeth L Inness ◽  
Cynthia J Danells ◽  
David Jagroop ◽  
Tanvi Bhatt ◽  
...  
Keyword(s):  
Older Adults ◽  
Balance Control ◽  
Controlled Trial ◽  
Balance Training ◽  
Optimal Dose ◽  
Pilot Randomised Controlled Trial ◽  
Healthy Older Adults ◽  
Randomised Controlled ◽  
Reactive Balance

IntroductionFalls risk poststroke is highest soon after discharge from rehabilitation. Reactive balance training (RBT) aims to improve control of reactions to prevent falling after a loss of balance. In healthy older adults, a single RBT session can lead to lasting improvements in reactive balance control and prevent falls in daily life. While increasing the dose of RBT does not appear to lead to additional benefit for healthy older adults, stroke survivors, who have more severely impaired balance control, may benefit from a higher RBT dose. Our long-term goal is to determine the optimal dose of RBT in people with subacute stroke. This assessor-blinded pilot randomised controlled trial aims to inform the design of a larger trial to address this long-term goal.Methods and analysisParticipants (n=36) will be attending out-patient stroke rehabilitation, and will be randomly allocated to one of three groups: one, three or six RBT sessions. RBT will replace a portion of participants’ regular physiotherapy so that the total physical rehabilitation time will be the same for the three groups. Balance and balance confidence will be assessed at: (1) study enrolment; (2) out-patient rehabilitation discharge; and (3) 6 months postdischarge. Participants will report falls and physical activity for 6 months postdischarge. Pilot data will be used to plan the larger trial (ie, sample size estimate using fall rates, and which groups should be included based on between-group trends in pre-to-post training effect sizes for reactive balance control measures). Pilot data will also be used to assess the feasibility of the larger trial (ie, based on the accrual rate, outcome completion rate and feasibility of prescribing specific training doses).Ethics and disseminationInstitutional research ethics approval has been received. Study participants will receive a lay summary of results. We will also publish our findings in a peer-reviewed journal.Trial registration numberNCT04219696; Pre results.

scholarly journals Examining Different Motor Learning Paradigms for Improving Balance Recovery Abilities Among Older Adults, Random vs. Block Training—Study Protocol of a Randomized Non-inferiority Controlled Trial

2021 ◽  
Vol 15 ◽  
Author(s):  
Hadas Nachmani ◽  
Inbal Paran ◽  
Moti Salti ◽  
Ilan Shelef ◽  
Itshak Melzer
Keyword(s):  
Older Adults ◽  
Balance Control ◽  
Controlled Trial ◽  
Training Session ◽  
Real Life ◽  
Community Dwelling ◽  
Analysis Of Covariance ◽  
Balance Function ◽  
Balance Test ◽  
Reactive Balance

Introduction: Falls are the leading cause of fatal and nonfatal injuries among older adults. Studies showed that older adults can reduce the risk of falls after participation in an unexpected perturbation-based balance training (PBBT), a relatively novel approach that challenged reactive balance control. This study aims to investigate the effect of the practice schedule (i.e., contextual interference) on reactive balance function and its transfer to proactive balance function (i.e., voluntary step execution test and Berg balance test). Our primary hypothesis is that improvements in reactive balance control following block PBBT will be not inferior to the improvements following random PBBT.Methods and Analysis: This is a double-blind randomized controlled trial. Fifty community-dwelling older adults (over 70 years) will be recruited and randomly allocated to a random PBBT group (n = 25) or a block PBBT group (n = 25). The random PBBT group will receive eight training sessions over 4 weeks that include unexpected machine-induced perturbations of balance during hands-free treadmill walking. The block PBBT group will be trained by the same perturbation treadmill system, but only one direction will be trained in each training session, and the direction of the external perturbations will be announced. Both PBBT groups (random PBBT and block PBBT) will receive a similar perturbation intensity during training (which will be customized to participant’s abilities), the same training period, and the same concurrent cognitive tasks during training. The generalization and transfer of learning effects will be measured by assessing the reactive and proactive balance control during standing and walking before and after 1 month of PBBT, for example, step and multiple steps and fall thresholds, Berg balance test, and fear of falls. The dependent variable will be rank transformed prior to conducting the analysis of covariance (ANCOVA) to allow for nonparametric analysis.Discussion: This research will explore which of the balance retraining paradigms is more effective to improve reactive balance and proactive balance control in older adults (random PBBT vs. block PBBT) over 1 month. The research will address key issues concerning balance retraining: older adults’ neuromotor capacities to optimize training responses and their applicability to real-life challenges.Clinical Trial Registration: Helsinki research ethics approval has been received (Soroka Medical Center approval #0396-16-SOR; MOH_2018-07-22_003536; www.ClinicalTrials.gov, NCT04455607).

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