scholarly journals Variability of Muscular Recruitment in Hemiplegic Walking Assessed by EMG Analysis

Electronics ◽  
2020 ◽  
Vol 9 (10) ◽  
pp. 1572
Author(s):  
Francesco Di Nardo ◽  
Susanna Spinsante ◽  
Chiara Pagliuca ◽  
Angelica Poli ◽  
Annachiara Strazza ◽  
...  
Keyword(s):  
Motor Development ◽  
Muscle Activity ◽  
Computational Procedure ◽  
Target Population ◽  
Type I ◽  
Subject Variability ◽  
Group 15 ◽  
Ankle Muscle ◽  
Gastrocnemius Lateralis ◽  
Adaptive Variability

Adaptive variability during walking is typical of child motor development. It has been reported that neurological disorders could affect this physiological phenomenon. The present work is designed to assess the adaptive variability of muscular recruitment during hemiplegic walking and to detect possible changes compared to control populations. In the attempt of limiting the complexity of computational procedure, the easy-to-measure coefficient of variation (CV) index is adopted to assess surface electromyography (sEMG) variability. The target population includes 34 Winters’ type I and II hemiplegic children (H-group). Two further healthy populations, 34 age-matched children (C-group) and 34 young adults (A-group), are involved as controls. Results show a significant decrease (p < 0.05) of mean CV for gastrocnemius lateralis (GL) in H-group compared to both C-group (15% reduction) and A-group (35% reduction). Reductions of mean CV are detected also for tibialis anterior (TA) in H-group compared to C-group (7% reduction, p > 0.05) and A-group (15% reduction, p < 0.05). Lower CVs indicate a decreased intra-subject variability of ankle-muscle activity compared to controls. Novel contribution of the study is twofold: (1) To propose a CV-based approach for an easy-to-compute assessment of sEMG variability in hemiplegic children, useful in different experimental environments and different clinical purposes; (2) to provide a quantitative assessment of the reduction of intra-subject variability of ankle-muscle activity in mild-hemiplegic children compared to controls (children and adults), suggesting that hemiplegic children present a limited capability of adapting their muscle recruitment to the different stimuli met during walking task. This finding could be very useful in deepening the knowledge of this neurological disorder.

scholarly journals Ankle Muscle Activations during Different Foot-Strike Patterns in Running

Sensors ◽  
2021 ◽  
Vol 21 (10) ◽  
pp. 3422
Author(s):  
Jian-Zhi Lin ◽  
Wen-Yu Chiu ◽  
Wei-Hsun Tai ◽  
Yu-Xiang Hong ◽  
Chung-Yu Chen
Keyword(s):  
Muscle Activity ◽  
Muscle Activation ◽  
Stance Phase ◽  
Inertial Sensors ◽  
Plantar Flexion ◽  
Intraclass Correlation ◽  
Biceps Femoris ◽  
Ankle Muscle ◽  
Foot Strike ◽  
Muscle Activations

This study analysed the landing performance and muscle activity of athletes in forefoot strike (FFS) and rearfoot strike (RFS) patterns. Ten male college participants were asked to perform two foot strikes patterns, each at a running speed of 6 km/h. Three inertial sensors and five EMG sensors as well as one 24 G accelerometer were synchronised to acquire joint kinematics parameters as well as muscle activation, respectively. In both the FFS and RFS patterns, according to the intraclass correlation coefficient, excellent reliability was found for landing performance and muscle activation. Paired t tests indicated significantly higher ankle plantar flexion in the FFS pattern. Moreover, biceps femoris (BF) and gastrocnemius medialis (GM) activation increased in the pre-stance phase of the FFS compared with that of RFS. The FFS pattern had significantly decreased tibialis anterior (TA) muscle activity compared with the RFS pattern during the pre-stance phase. The results demonstrated that the ankle strategy focused on controlling the foot strike pattern. The influence of the FFS pattern on muscle activity likely indicates that an athlete can increase both BF and GM muscles activity. Altered landing strategy in cases of FFS pattern may contribute both to the running efficiency and muscle activation of the lower extremity. Therefore, neuromuscular training and education are required to enable activation in dynamic running tasks.

A critical period for the impact of vestibular sensation on ferret motor development

2007 ◽  
Vol 16 (4-5) ◽  
pp. 179-186
Author(s):  
S. Van Cleave ◽  
M.S. Shall
Keyword(s):  
Vestibular System ◽  
Motor Development ◽  
Critical Period ◽  
Motor Behavior ◽  
Fiber Development ◽  
Type I ◽  
Behavior Development ◽  
Sham Surgery ◽  
Walking Balance ◽  
The Impact

Children with hearing deficits and hypofunctioning vestibular receptors frequently have delayed motor development. This study focuses on when the vestibular system needs to be active for normal motor behavior development and the maturation of the soleus muscle in the ferret. Both vestibular labyrinths were removed from ferrets at Postnatal day 10 (P10), P21, or P45 and the resulting data were compared with ferrets that had undergone a sham surgery at the same ages. The animals were sacrificed at P120 (young adult ferret). The resulting data from these ferrets revealed that standing and walking balance was significantly affected when the vestibular system was eliminated at or before P21. The soleus of P10 and P21 animals generally had smaller diameter muscle fibers and proportionally less type I Myosin Heavy Chain (MHC) and more type IIX MHC. The twitch contraction time of the soleus of the P21 group was significantly slower than the other groups. It appears that the vestibular system is important to motor and muscle fiber development in the ferret during the period before P21. The eyes are still closed at that age and all of the vestibular receptors are not fully mature. These findings imply a "critical period" for vestibular sensation and the development of a muscle that is important to standing balance.

scholarly journals Competition Between Cyclization and Unusual Norrish Type I and Type II Nitro-Acyl Migration Pathways in the Photouncaging of 1-Acyl-7-nitroindoline Revealed by Computations

2020 ◽  
Author(s):  
Pierpaolo Morgante ◽  
Charitha Guruge ◽  
Yannick P. Ouedraogo ◽  
Nasri Nesnas ◽  
Roberto Peverati
Keyword(s):  
Density Functional ◽  
Acyl Migration ◽  
Density Functional Theory Calculations ◽  
Computational Procedure ◽  
Quantum Yields ◽  
Type I ◽  
Type Ii ◽  
Relative Quantum ◽  
Norrish Type ◽  
Migration Pathways

The 7-nitroindolinyl family of caging chromophores has received much attention in the past two decades. However, its uncaging mechanism is still not clearly understood. In this study, we performed state-of-the-art density functional theory calculations to unravel the photo-uncaging mechanism in its entirety, and we compared the probabilities of all plausible pathways. We found competition between a classical cyclization and acyl migration pathways, and here we explain the electronic and steric reasons behind such competition. The migration mechanism possesses the characteristics of a combined Norrish Type I and a 1,6-nitro-acyl variation of a Norrish Type II mechanism, which is reported here for the first time. We also introduced a computational procedure that allows the estimation of intersystem crossing rate constants useful to compare the relative quantum yield of substituted cages. This procedure may pave the way for improved cage designs that possess higher quantum yields and a more efficient agonist release.<br>

scholarly journals The effect of hyper-pronated foot on postural control and ankle muscle activity during running and cutting movement

2020 ◽  
Vol 14 (4) ◽  
pp. 216-220
Author(s):  
Zahed Mantashloo ◽  
Heydar Sadeghi ◽  
Mehdi Khaleghi Tazji ◽  
Vanessa Rice ◽  
Elizabeth J Bradshaw
Keyword(s):  
Postural Control ◽  
Muscle Activity ◽  
Muscle Activation ◽  
Cross Sectional Study ◽  
The Body ◽  
Lateral Direction ◽  
Cross Sectional ◽  
Activation Patterns ◽  
Muscle Activation Patterns ◽  
Ankle Muscle

Objective: The aim of this study was to examine the effect of hyper pronated foot on postural control and ankle muscle activity during running and cutting movement (v-cut). Methods: In this Cross-Sectional study, 42 young physically active (exercising three times per week regularly) males participated in this study, including 21 with hyper-pronated feet and 21 with normal feet. Each participant completed a running and cutting task. Body postural control was measured using a force platform (1000Hz) which was synchronized with surface electromyography of selected ankle muscles. MATLAB software was used to process and analyze the data. One-away ANOVA was used to identify any differences between groups. Results: Differing muscle activation patterns in the surrounding ankle musculature (tibialis anterior, peroneus longus) through to reduced postural stability in the medial-lateral direction and increased vertical ground reaction forces were observed between groups. Conclusion: According to the obtained results it seems that subtalar hyper-pronation can be regarded as a factor affecting the biomechanics of cutting by changing activation patterns of the muscles surrounding the ankle, and reducing postural control of the body in medial-lateral direction, but not in anterior-posterior direction.

scholarly journals Effects on Ankle Muscle Activity of the Tilt Direction of a Balance Board

2018 ◽  
Vol 33 (3) ◽  
pp. 395-400
Author(s):  
Miho MORITA ◽  
Yukio URABE ◽  
Takuya TAKEUCHI ◽  
Noriaki MAEDA
Keyword(s):  
Muscle Activity ◽  
Ankle Muscle ◽  
Balance Board

Single low-threshold afferents innervating the skin of the human foot modulate ongoing muscle activity in the upper limbs

2013 ◽  
Vol 109 (6) ◽  
pp. 1614-1625 ◽  
Author(s):  
Leah R. Bent ◽  
Catherine R. Lowrey
Keyword(s):  
Upper Limb ◽  
Muscle Activity ◽  
Reflex Response ◽  
Cutaneous Afferents ◽  
Type I ◽  
Triceps Brachii ◽  
Median Response ◽  
Plantar Surface ◽  
Human Foot ◽  
Low Threshold

We have shown for the first time that single cutaneous afferents in the foot dorsum have significant reflex coupling to motoneurons supplying muscles in the upper limb, particularly posterior deltoid and triceps brachii. These observations strengthen what we know from whole nerve stimulation, that skin on the foot and ankle can contribute to the modulation of interlimb muscles in distant innervation territories. The current work provides evidence of the mechanism behind the reflex, where one single skin afferent can evoke a reflex response, rather than a population. Nineteen of forty-one (46%) single cutaneous afferents isolated in the dorsum or plantar surface of the foot elicited a significant modulation of muscle activity in the upper limb. Identification of single afferents in this reflex indicates the strength of the connection and, ultimately, the importance of foot skin in interlimb coordination. The median response magnitude was 2.29% of background EMG, and the size of the evoked response did not significantly differ among the four mechanoreceptor classes ( P > 0.1). Interestingly, although the distribution of afferents types did not differ across the foot dorsum, there was a significantly greater coupling response from receptors located on the medial aspect of the foot dorsum ( P < 0.01). Furthermore, the most consistent coupling with upper limb muscles was demonstrated by type I afferents (fast and slowly adapting). This work contributes to the current literature on receptor specificity, supporting the view that individual classes of cutaneous afferents may subserve specific roles in kinesthesia, reflexes, and tactile perception.

Electromyographic and Safety Comparisons of Common Lower Limb Rehabilitation Exercises for People With Hemophilia

2019 ◽  
Author(s):  
Joaquín Calatayud ◽  
Sofía Pérez-Alenda ◽  
Juan J Carrasco ◽  
Adrián Escriche-Escuder ◽  
Carlos Cruz-Montecinos ◽  
...  
Keyword(s):  
Lower Limb ◽  
Muscle Activity ◽  
Plantar Flexion ◽  
Rectus Femoris ◽  
Knee Extension ◽  
Activity Levels ◽  
External Resistance ◽  
Elastic Resistance ◽  
Ankle Plantar Flexion ◽  
Gastrocnemius Lateralis

Abstract Background Ankles and knees are commonly affected in people with hemophilia and thus are targets for prevention or rehabilitation. However, to our knowledge, no studies have evaluated muscle activity and safety during exercises targeting the lower limbs in people with hemophilia; this lack of information hinders clinical decision-making. Objective The aim of this study was to compare the tolerability of, safety of, and muscle activity levels obtained with external resistance (elastic or machine)–based and non–external resistance–based lower limb exercises in people with hemophilia. Design This was a cross-sectional study. Methods Eleven people who had severe hemophilia and were undergoing prophylactic treatment participated. In a single experimental session, participants performed knee extension and ankle plantar flexion during 3 exercise conditions in random order: elastic band–based resistance (elastic resistance), machine-based resistance (machine resistance), and no external resistance. Exercise intensities for the 2 external resistance–based conditions were matched for perceived exertion. Muscle activity was determined using surface electromyography (EMG) for the rectus femoris, biceps femoris, gastrocnemius lateralis, and tibialis anterior muscles. Participants were asked to rate exercise tolerability according to a scale ranging from “very well tolerated” to “not tolerated” and to report possible adverse effects 24 and 48 hours after the session. Results No adverse effects were reported, and exercise tolerability was generally high. In the knee extension exercise, the rectus femoris normalized EMG values during the elastic resistance and machine resistance conditions were similar; 29% to 30% higher activity was obtained during these conditions than during the non–external resistance condition. In the ankle plantar flexion exercise, the gastrocnemius lateralis normalized EMG value was 34% higher during the machine resistance condition than without external resistance, and the normalized EMG values during the elastic resistance and other conditions were similar. Limitations The small sample size and single training session were the primary limitations of this study. Conclusions Exercises performed both with elastic bands and with machines at moderate intensity are safe, feasible, and efficient in people with severe hemophilia, providing comparable activity levels in the agonist muscles.

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