scholarly journals Cardiovascular and nitric oxide response after maximal voluntary isometric contraction in adolescents with and without Down Syndrome

2022 ◽  
Vol 11 (1) ◽  
pp. e50011125342
Author(s):  
Geiziane Leite Rodrigues Melo ◽  
Milton Rocha Moraes ◽  
Weldson Ferreira Abreu ◽  
Rafael Reis Olher ◽  
Lysleine Alves Deus ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Down Syndrome ◽  
Isometric Contraction ◽  
Maximal Voluntary Isometric Contraction ◽  
Leg Press ◽  
Óxido Nítrico

Este estudo teve como objetivo comparar as respostas cardiovasculares e de óxido nítrico (NO) à contração isométrica voluntária máxima (CIVM) com diferentes grupos musculares (leg press [LEP] e preensão manual isométrica [IHG]) de adolescentes com e sem síndrome de Down (SD). Alem de comparar a força IHG absoluta e relativa entre os grupos. Onze adolescentes com SD (14,1 ± 1,0 anos) e dez sem SD (13,7 ± 1,25 anos) realizaram duas sessões experimentais de exercícios LEP e IHG: 1) sessão de familiarização e 2) 3 tentativas x 5 segundos de contração na CIVM com 3- intervalo mínimo de descanso. A pressão arterial (PA), a frequência cardíaca (FC) e o NO foram coletados em repouso, imediatamente após a sessão de exercício e 10 minutos após o exercício. A dosagem de NO na saliva foi realizada pelo método colorimétrico de Griess. Não houve diferenças para respostas cardiovasculares e NO entre os grupos para CIVM. No entanto, o SD teve uma resposta cardiovascular menor, mas não significativamente, em repouso e após os testes de CIVM do que aqueles sem SD. O grupo SD apresentou maior concentração de NO em repouso, recuperação e após IHG quando comparado ao grupo não SD (P <0,05). Além disso, adolescentes com SD apresentaram menor nível de força de IHG absoluta e relativa quando comparados àqueles sem SD (P = 0,001). Indivíduos com SD apresentam menor resposta cardiovascular em repouso e após testes de CIVM e maior resposta de NO após o exercício quando comparados ao grupo sem SD.

Cardiovascular and nitric oxide response after maximal voluntary isometric contraction in adolescents with and without Down Syndrome v1

2021 ◽  
Author(s):  
Geiziane Leite Rodrigues Melo ◽  
Dahan Cunha Nascimento ◽  
Weldson Abreu ◽  
Rafael Olher ◽  
Lysleine Deus ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Down Syndrome ◽  
Isometric Contraction ◽  
Cardiovascular Response ◽  
Exercise Session ◽  
Isometric Handgrip ◽  
Maximal Voluntary Isometric Contraction ◽  
Post Exercise ◽  
Muscle Groups ◽  
Familiarization Session

Background This study was designed to compare the cardiovascular and nitric oxide (NO) responses to maximal voluntary isometric contraction (MVIC) with different muscle groups (leg press [LEP] and isometric handgrip [IHG] exercise) of adolescents with Down syndrome (DS) and age-matched non-DS peers. We also aimed to compare the absolute and relative IHG strength between groups. MethodsEleven adolescents with DS (14.1 ± 1.0 years) and ten without DS (13.7 ± 1.25 years)participants performed two experimental sessions of LEP and IHG exercises: 1) familiarization session and 2) 3 attempts x 5-sec contraction at MVIC with 3-min rest interval. Blood pressure (BP), heart rate (HR) and NO were collected at rest, immediately post-exercise session, and 10-min post-exercise. Results There were no differences for cardiovascular and NO responses between groups for MVIC test using different muscle groups. However, DS group displayed a lower but not significantly cardiovascular response at rest and after MVIC tests than controls. Furthermore, DS group displayed a higher NO- concentration at rest, recovery and after IHG when compared to controls (P< 0.05). In addition, DS adolescents displayed a significantly lower level in absolute and relative IHG strength when compared to controls (P = 0.001). Conclusions Individuals with DS display a lower cardiovascular response at rest and after MVIC tests than controls and higher NO response after exercise.

scholarly journals Reliability of Motor Unit Behavior during a Maximal Voluntary Isometric Contraction of the Knee Extensors

2019 ◽  
Vol 51 (Supplement) ◽  
pp. 340-341
Author(s):  
Ryan J. Colquhoun ◽  
Patrick M. Tomko ◽  
Mitchel A. Magrini ◽  
Sydnie R. Fleming ◽  
Matthew C. Ferrell ◽  
...  
Keyword(s):  
Motor Unit ◽  
Isometric Contraction ◽  
Knee Extensors ◽  
Maximal Voluntary Isometric Contraction

Simultaneous potentiation and fatigue in quadriceps after a 60-second maximal voluntary isometric contraction

1991 ◽  
Vol 70 (2) ◽  
pp. 726-731 ◽  
Author(s):  
R. W. Grange ◽  
M. E. Houston
Keyword(s):  
Isometric Contraction ◽  
Recovery Period ◽  
Lactate Concentration ◽  
Fold Increase ◽  
Quadriceps Muscle ◽  
Muscle Performance ◽  
Light Chains ◽  
Maximal Voluntary Isometric Contraction ◽  
Muscle Lactate ◽  
Isometric Twitch

Potential mechanisms of fatigue (metabolic factors) and potentiation (phosphate incorporation by myosin phosphorylatable light chains) were investigated during recovery from a 60-s maximal voluntary isometric contraction (MVC) in the quadriceps muscle of 12 subjects. On separate days before and for 2 h after the 60-s MVC, either a 1-s MVC or electrically stimulated contractions were used as indexes to test muscle performance. Torque at the end of the 60-s MVC was 57% of the initial level, whereas torques from a 1-s MVC and 50-Hz stimulation were most depressed in the immediate recovery period. At this time, muscle biopsy analyses revealed significant decreases in ATP and phosphocreatine and a 19-fold increase in muscle lactate. Conversely, isometric twitch torque and torque from a 10-Hz stimulus were the least depressed of six contractile indexes and demonstrated potentiation of 25 and 34%, respectively, by 4 min of recovery (P less than 0.05). At this time, muscle lactate concentration was still 16 times greater than at rest. An increased phosphate content of the myosin phosphorylatable light chains (P less than 0.05) was also evident both immediately and 4 min after the 60-s MVC. We conclude that the 60-s MVC produced marked force decreases likely due to metabolic displacement, while the limited decline in the twitch and 10-Hz torques and their significant potentiation suggested that myosin phosphorylation may provide a mechanism to enhance contractile force under conditions of submaximal activation during fatigue.

scholarly journals Acute Neuromuscular Electrical Stimulation (NMES) With Blood Flow Restriction: The Effect of Restriction Pressures

2020 ◽  
pp. 1-9
Author(s):  
Paul Head ◽  
Mark Waldron ◽  
Nicola Theis ◽  
Stephen David Patterson
Keyword(s):  
Blood Flow ◽  
Electrical Stimulation ◽  
Isometric Contraction ◽  
Perceived Exertion ◽  
Neuromuscular Electrical Stimulation ◽  
Muscle Thickness ◽  
Ratings Of Perceived Exertion ◽  
Experimental Conditions ◽  
Maximal Voluntary Isometric Contraction ◽  
Flow Restriction

Context: Neuromuscular electrical stimulation (NMES) combined with blood flow restriction (BFR) has been shown to improve muscular strength and size better than NMES alone. However, previous studies used varied methodologies not recommended by previous NMES or BFR research. Objective: The present study investigated the acute effects of NMES combined with varying degrees of BFR using research-recommended procedures to enhance understanding and the clinical applicability of this combination. Design: Randomized crossover. Setting: Physiology laboratory. Participants: A total of 20 healthy adults (age 27 [4] y; height 177 [8] cm; body mass 77 [13] kg). Interventions: Six sessions separated by at least 7 days. The first 2 visits served as familiarization, with the experimental conditions performed in the final 4 sessions: NMES alone, NMES 40% BFR, NMES 60% BFR, and NMES 80% BFR. Main Outcome Measures: Maximal voluntary isometric contraction, muscle thickness, blood pressure, heart rate, rating of perceived exertion, and pain were all recorded before and after each condition. Results: The NMES 80% BFR caused greater maximal voluntary isometric contraction decline than any other condition (−38.9 [22.3] N·m, P < .01). Vastus medialis and vastus lateralis muscle thickness acutely increased after all experimental conditions (P < .05). Pain and ratings of perceived exertion were higher after NMES 80% BFR compared with all other experimental conditions (P < .05). No cardiovascular effects were observed between conditions. Conclusion: The NMES combined with 80% BFR caused greater acute force decrement than the other conditions. However, greater perceptual ratings of pain and ratings of perceived exertion were observed with NMES 80% BFR. These acute observations must be investigated during chronic interventions to corroborate any relationship to changes in muscle strength and size in clinical populations.

scholarly journals Effect of Hip Abduction Maximal Voluntary Isometric Contraction on Lumbar Motion and Power Output During the Back Squat

2018 ◽  
Vol 6 (1) ◽  
pp. 1
Author(s):  
Christopher F. Kelly ◽  
Adam M. Gonzalez ◽  
Robert W. Spitz ◽  
Katie M. Sell ◽  
Jamie J. Ghigiarelli
Keyword(s):  
Isometric Contraction ◽  
Power Output ◽  
Maximum Deviation ◽  
Lateral Flexion ◽  
Maximal Voluntary Isometric Contraction ◽  
Lumbar Flexion ◽  
Back Squat ◽  
Squat Exercise ◽  
Hip Abduction ◽  
Lumbar Motion

Background: Post-activation potentiation (PAP) is a neuromuscular phenomenon that has been shown to augment muscular force generating attributes as well as neural and sensory recruitment. While PAP has demonstrated to acutely enhance muscular performance during high-intensity activities, the effect of PAP on lumbopelvic kinematics under load remains unknown. Objectives: The purpose of this study was to examine the potential PAP effect of a hip abduction maximal voluntary isometric contraction (MVIC) on lumbar motion and power output during the barbell back squat.  Methods: Nine resistance-trained men (22.9±2.3 y; 85.0±13.8 kg; 174.3±5.1 cm) performed a set of 5 repetitions of the barbell back squat using 80% one-repetition maximum with and without a hip abduction MVIC prior to performance.  Experimental and control trials were randomized and counterbalanced among participants.  MVIC was carried out via manual long-lever hip abduction.  During the back squat exercise, lumbar motion analysis was performed using wireless motion-sensor technology, and power output was assessed via an accelerometer.  Results: No significant differences were observed between trials for lumbar flexion range of motion (ROM) (p=0.32), lumbar flexion maximum deviation (p=0.32), lumbar lateral flexion ROM (p=0.81), lumbar lateral flexion maximum deviation (p=0.98), lumbar rotation maximum deviation (p=0.70), average peak power (p=0.98), or average mean power output (p=0.99) during the squat protocol.  Conclusions: Implementation of a manual long-lever hip abduction MVIC prior to the back squat exercise did not significantly alter lumbar motion or augment power output in resistance trained males. 

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