Characteristics of Postural Muscle Activity in Response to A Motor-Motor Task in Elderly

The purpose of the current study was to evaluate postural muscle performance of older adults in response to a combination of two motor tasks perturbations. Fifteen older participants were instructed to perform a pushing task as an upper limb perturbation while standing on a fixed or sliding board as a lower limb perturbation. Postural responses were characterized by onsets and magnitudes of muscle activities as well as onsets of segment movements. (Please see full abstract article

Task-dependent Modulation of Cortical Excitability and Balance Control in Individuals with Post-concussion Syndrome

In most cases, symptoms resolve between 7-10 days post-concussion. However, in 10-15% of the concussed population, symptoms can remain unresolved for months to years following the head injury. The purpose of this thesis was two-fold, and was broken up into two studies, where the same individuals participated in both studies. The purpose of the first study was to quantify the differences in balance control between individuals with PCS (i.e., had been experiencing symptoms for \u3c30 days) and non-concussed individuals during a lower-limb reaching task. Participants completed a static balance assessment before and after a lower-limb reaching task, which incorporated a Go/No-Go paradigm. Results from this study revealed no differences in the static stability assessments, however, individuals with PCS demonstrated increased medial-lateral COP displacement as well as greater trunk pitch during the reaching task. Overall, the findings reveal persistent balance impairments in individuals with PCS, which may put this population at an increased risk of further injury. The purpose of the second study was to assess task-dependent modulation of cortical excitability prior to planned index finger abduction contractions comparing a non-concussed population to a population with PCS. The protocol in this study consisted of both single and paired-pulse transcranial magnetic stimulation (TMS) which was applied prior to the beginning of 3 different tasks (i.e., a rest condition with no plan to contract, a precision contraction, and a powerful contraction). In addition to the three tasks, participants also had to respond to a Go/No-Go cue. The results of this study revealed an increase in excitability prior to a precision contraction in both non-concussed and PCS groups. No differences in task-dependent modulation were found between the two groups with respect to intracortical facilitation and inhibition, however a negative correlation between number of symptoms reported (SCAT3 symptom evaluation) and intracortical facilitation was revealed. The increase in corticospinal excitability prior to a precision contraction was not explained by the two cortical mechanisms we assessed and may therefore be due to spinal modulation or a different cortical mechanism. Overall, based on the results from this thesis, it appears that individuals with PCS have balance impairments, which may be a result of an inability to maximally activate their postural muscles. Furthermore, it appears that those individuals who reported a higher number of symptoms had greater reductions in intracortical facilitation, likely reflecting the heterogeneity of this clinical group

The effectiveness of neuromuscular warm-up strategies, that require no additional equipment, for preventing lower limb injuries during sports participation: a systematic review

PMCID: PMC3408383The electronic version of this article is the complete one and can be found online at: http://www.biomedcentral.com/1741-7015/10/75. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited

Profiling the sport of stand-up paddle boarding

Stand-up paddle boarding (SUP) is a rapidly growing activity where only anecdotal evidence exists for its proposed health and fitness benefits. The purpose of this study was to profile elite and recreational SUP with respect to anthropometric, physiological and musculoskeletal measurements. A total of 30 SUP participants (15 recreational, 15 elite) and 15 sedentary controls participated in this study. Elite and recreational (rec) SUP participants had significantly lower body fat than sedentary (sed) individuals, elite had significantly higher HDL and significantly lower triglycerides than other groups during lipid profiling (P \u3e 0.05). There were significant differences (P \u3e 0.05) between all groups in maximal oxygen uptake (elite 43.7, s = 5.89 ml · kg–1 · min–1 vs. rec 31.9, s = 7.7 ml · kg–1 · min–1 vs. sed 20.4, s = 3.7 ml · kg–1 · min–1) and anaerobic power outputs (35.7, s = 11.1 W vs. 25.0, s = 11.7 W vs. 13.5, s = 7.1 W). The elite group displayed significantly longer endurance than the recreational and sedentary group in the prone bridge (elite 253.4, s = 67.6 s vs. rec 165.6, s = 42.2 s vs. sed 69.7, s = 31.2 s), right-sided bridge (elite 107.9, s = 34.0 s vs. recreational 68.2, s = 24.1 s vs. sed 34.6, s = 15.5 s), left-sided bridge (elite 99.8, s = 24.9 s vs. rec 68.2, s = 27.2 s vs. sed 32.5, s = 15.2 s) and Biering Sorensen test (elite 148.8, s = 35.4 s vs. rec 127.2, s = 43.2 s vs. sed 71.1, s = 32.9 s). Elite SUP had significantly better static and dynamic postural control when compared to the other groups. This study demonstrates the anthropometric, physiological and musculoskeletal values representative of elite and recreational SUP. SUP appears to be associated with increased levels of aerobic and anaerobic fitness, increased static and dynamic balance and a high level of isometric trunk endurance

Fatiguing Effects of Indirect Vibration Stimulation in Upper Limb Muscles- pre, post and during Isometric Contractions Superimposed on Upper Limb Vibration

© 2019 The Authors. Published by the Royal Society under the terms of the Creative Commons Attribution License http://creativecommons.org/licenses/by/4.0/ , which permits unrestricted use, provided the original author and source are credited.Whole-body vibration and upper limb vibration (ULV) continue to gain popularity as exercise intervention for rehabilitation and sports applications. However, the fatiguing effects of indirect vibration stimulation are not yet fully understood. We investigated the effects of ULV stimulation superimposed on fatiguing isometric contractions using a purpose developed upper limb stimulation device. Thirteen healthy volunteers were exposed to both ULV superimposed to fatiguing isometric contractions (V) and isometric contractions alone Control (C). Both Vibration (V) and Control (C) exercises were performed at 80% of the maximum voluntary contractions. The stimulation used was 30 Hz frequency of 0.4 mm amplitude. Surface-electromyographic (EMG) activity of the Biceps Brachii, Triceps Brachii and Flexor Carpi Radialis were measured. EMG amplitude (EMGrms) and mean frequency (MEF) were computed to quantify muscle activity and fatigue levels. All muscles displayed significantly higher reduction in MEFs and a corresponding significant increase in EMGrms with the V than the Control, during fatiguing contractions (p < 0.05). Post vibration, all muscles showed higher levels of MEFs after recovery compared to the control. Our results show that near-maximal isometric fatiguing contractions superimposed on vibration stimulation lead to a higher rate of fatigue development compared to the isometric contraction alone in the upper limb muscles. Results also show higher manifestation of mechanical fatigue post treatment with vibration compared to the control. Vibration superimposed on isometric contraction not only seems to alter the neuromuscular function during fatiguing efforts by inducing higher neuromuscular load but also post vibration treatment.Peer reviewedFinal Published versio