Severe acute hypoxia impairs recovery of voluntary muscle activation after sustained submaximal elbow flexion

2021 ◽  
Author(s):  
Daniel J. McKeown ◽  
Chris J. McNeil ◽  
Emily J. Brotherton ◽  
Michael J. Simmonds ◽  
Justin J. Kavanagh
Keyword(s):  
Muscle Activation ◽  
Acute Hypoxia ◽  
Elbow Flexion ◽  
Voluntary Muscle

Voluntary muscle activation varies with age and muscle group

2002 ◽  
Vol 93 (2) ◽  
pp. 457-462 ◽  
Author(s):  
Jennifer M. Jakobi ◽  
Charles L. Rice
Keyword(s):  
Muscle Activation ◽  
Age Groups ◽  
Young Men ◽  
Elbow Flexion ◽  
Muscle Group ◽  
Elbow Flexor ◽  
Elbow Flexors ◽  
Voluntary Muscle ◽  
Muscle Groups ◽  
Old Men

The consistency and the number of attempts required to achieve maximal voluntary muscle activation have not been documented and compared between young and old adults. Furthermore, few studies have contrasted activation between functional pairs of muscle groups, and no study has tested upper limb muscles. The purpose of this study was to measure and compare voluntary muscle activation of the elbow flexors and extensors in young and old men over two separate test sessions. With the method of twitch interpolation to measure activation, six young (24 ± 1 yr) and six old (83 ± 4 yr) men performed five maximal voluntary contractions (MVC) during each session for each muscle group. Elbow flexion and extension MVC was less (43 and 47%, respectively) in the old men, yet the best maximal voluntary muscle activation was similar between age groups. However, when all 10 attempts at MVC were compared, the mean activation scores were slightly less (∼5%) in the elbow extensors but were ∼11% less ( P < 0.001) in the elbow flexors of old men, compared with young men. During the second session, there was a significant improvement of 13% ( P< 0.005) in mean elbow flexor activation in the old men. There were no session differences for either muscle group for the young men. The results indicate that, for aged men, elbow flexor maximal activation is achieved less frequently compared with elbow extensors, and thus mean activation for elbow flexors is less than for elbow extensors. However, if sufficient attempts are provided, the best effort for the old men is not different from that of the young men for either muscle group.

scholarly journals Differential muscle function between muscle synergists: long and lateral heads of the triceps in jumping and landing goats (Capra hircus)

2008 ◽  
Vol 105 (4) ◽  
pp. 1262-1273 ◽  
Author(s):  
Andrew M. Carroll ◽  
David V. Lee ◽  
Andrew A. Biewener
Keyword(s):  
Muscle Function ◽  
High Speed ◽  
Muscle Activation ◽  
Reaction Force ◽  
Elbow Flexion ◽  
Capra Hircus ◽  
Triceps Brachii ◽  
Joint Work ◽  
Long Head ◽  
Lateral Head

We investigate how the biarticular long head and monoarticular lateral head of the triceps brachii function in goats ( Capra hircus) during jumping and landing. Elbow moment and work were measured from high-speed video and ground reaction force (GRF) recordings. Muscle activation and strain were measured via electromyography and sonomicrometry, and muscle stress was estimated from elbow moment and by partitioning stress based on its relative strain rate. Elbow joint and muscle function were compared among three types of limb usage: jump take-off (lead limb), the step prior to jump take-off (lag limb), and landing. We predicted that the strain and work patterns in the monoarticular lateral head would follow the kinematics and work of the elbow more closely than would those of the biarticular long head. In general this prediction was supported. For instance, the lateral head stretched (5 ± 2%; mean ± SE) in the lead and lag limbs to absorb work during elbow flexion and joint work absorption, while the long head shortened (−7 ± 1%) to produce work. During elbow extension, both muscles shortened by similar amounts (−10 ± 2% long; −13 ± 4% lateral) in the lead limb to produce work. Both triceps heads functioned similarly in landing, stretching (13 ± 3% in the long head and 19 ± 5% in the lateral) to absorb energy. In general, the long head functioned to produce power at the shoulder and elbow, while the lateral head functioned to resist elbow flexion and absorb work, demonstrating that functional diversification can arise between mono- and biarticular muscle agonists operating at the same joint.

scholarly journals Reduced Maximal Force during Acute Anterior Knee Pain Is Associated with Deficits in Voluntary Muscle Activation

PLoS ONE ◽  
2016 ◽  
Vol 11 (8) ◽  
pp. e0161487 ◽  
Author(s):  
Sauro Salomoni ◽  
Kylie Tucker ◽  
François Hug ◽  
Megan McPhee ◽  
Paul Hodges
Keyword(s):  
Knee Pain ◽  
Anterior Knee Pain ◽  
Muscle Activation ◽  
Voluntary Muscle ◽  
Maximal Force ◽  
Anterior Knee

Impaired inhibition in writer's cramp during voluntary muscle activation

Neurology ◽  
1997 ◽  
Vol 49 (4) ◽  
pp. 1054-1059 ◽  
Author(s):  
R. Chen ◽  
E. M. Wassermann ◽  
M. Canos ◽  
M. Hallett
Keyword(s):  
Muscle Activation ◽  
Voluntary Muscle ◽  
Writer’S Cramp ◽  
Writer's Cramp

scholarly journals Muscle Activation During Exercise in Severe Acute Hypoxia: Role of Absolute and Relative Intensity

2014 ◽  
Vol 15 (4) ◽  
pp. 472-482 ◽  
Author(s):  
Rafael Torres-Peralta ◽  
José Losa-Reyna ◽  
Miriam González-Izal ◽  
Ismael Perez-Suarez ◽  
Jaime Calle-Herrero ◽  
...  
Keyword(s):  
Relative Intensity ◽  
Muscle Activation ◽  
Acute Hypoxia

Effect of Task Difficulty on Muscle Activation Patterns during Rapid Single-Joint Movements

2002 ◽  
Vol 94 (3_suppl) ◽  
pp. 1157-1167 ◽  
Author(s):  
Sangbum Park
Keyword(s):  
Task Difficulty ◽  
Muscle Activation ◽  
Biceps Brachii ◽  
Elbow Flexion ◽  
Movement Initiation ◽  
Antagonist Muscle ◽  
Muscle Activation Patterns ◽  
Movement Organization ◽  
Agonist And Antagonist ◽  
Index Of Difficulty

This study investigated the effect of spatial accuracy demands on movement organization by analyzing the amplitude of the agonist and antagonist muscle activities emerging during horizontal elbow-flexion movements toward spatial targets of varying difficulties. 8 subjects performed elbow-flexion movements toward targets of 3 sizes, located at 2 distances, as rapidly and accurately as possible. For each movement, the elbow angles and the activities of biceps brachii, brachioradialis, and lateral and long heads of triceps brachii were measured. Analysis on the kinematic variables indicated that final elbow angle and peak velocity decreased with increasing index of difficulty of the task in both movement-amplitude conditions. However, movement time increased with increasing index of difficulty. The amplitude of agonist and antagonist muscle activities measured for 100 msec. before movement initiation was also shown to decrease with increasing index of difficulty. Agonist and antagonist muscle activities measured during acceleration phase displayed similar patterns with those of premovement. These results suggest that the task difficulty affects movement organization, and the control system decreases the amplitude of agonist and antagonist muscle activities with an increase in the index of difficulty to enhance the controllability of the limb.

scholarly journals Child–adult differences in muscle strength and activation pattern during isometric elbow flexion and extension

2009 ◽  
Vol 34 (4) ◽  
pp. 609-615 ◽  
Author(s):  
Bareket Falk ◽  
Charlotte Usselman ◽  
Raffy Dotan ◽  
Laura Brunton ◽  
Panagiota Klentrou ◽  
...  
Keyword(s):  
Muscle Strength ◽  
Muscle Activation ◽  
Motor Units ◽  
Elbow Flexion ◽  
Peak Torque ◽  
Electromechanical Delay ◽  
Cross Sectional ◽  
Rate Of Torque Development ◽  
Torque Development ◽  
Flexion And Extension

Muscle strength and activation were compared in boys and men during maximal voluntary elbow flexion and extension contractions. Peak torque, peak rate of torque development (dτ/dτmax), rate of muscle activation, and electromechanical delay (EMD) were measured in 15 boys (aged 9.7 ± 1.6 years) and 16 men (aged 22.1 ± 2.8 years). During flexion, peak torque was significantly lower in boys than in men (19.5 ± 5.8 vs. 68.5 ± 11.0 Nm, respectively; p < 0.05), even when controlling for upper-arm cross-sectional area (CSA), and peak electromyography activity. Boys also exhibited a lower normalized dτ/dτmax (7.2 ± 1.7 vs. 9.5 ± 1.6 (Nm·s–1)·(Nm–1), respectively; p < 0.05) and a significantly longer EMD (75.5 ± 28.4 vs. 47.6 ± 17.5 ms, respectively). The pattern was similar for extension, except that group differences in peak torque were no longer significant when normalized for CSA. These results suggest that children may be less able to recruit or fully utilize their higher-threshold motor units, resulting in lower dimensionally normalized maximal torque and rate of torque development.

Fatigue induced changes in phasic muscle activation patterns for fast elbow flexion movements

2002 ◽  
Vol 142 (1) ◽  
pp. 1-12 ◽  
Author(s):  
Daniel Corcos ◽  
Hai-Ying Jiang ◽  
Janey Wilding ◽  
Gerald Gottlieb
Keyword(s):  
Muscle Activation ◽  
Elbow Flexion ◽  
Activation Patterns ◽  
Muscle Activation Patterns ◽  
Induced Changes
Sign in / Sign up

Export Citation Format

Share Document