Relative variability in muscle activation amplitude, muscle oxygenation, and muscle thickness: Changes with dynamic low-load elbow flexion fatigue and relationships in young and older females

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.

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Comparison between muscle activation measured by electromyography and muscle thickness measured using ultrasonography for effective muscle assessment

Journal of Electromyography and Kinesiology ◽

10.1016/j.jelekin.2014.07.002 ◽

2014 ◽

Vol 24 (5) ◽

pp. 614-620 ◽

Cited By ~ 14

Author(s):

Chang-Yong Kim ◽

Jong-Duk Choi ◽

Suhn-Yeop Kim ◽

Duck-Won Oh ◽

Jin-Kyung Kim ◽

...

Keyword(s):

Muscle Activation ◽

Muscle Thickness

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Individual Responses for Muscle Activation, Repetitions, and Volume during Three Sets to Failure of High- (80% 1RM) versus Low-Load (30% 1RM) Forearm Flexion Resistance Exercise

Sports ◽

10.3390/sports3040269 ◽

2015 ◽

Vol 3 (4) ◽

pp. 269-280 ◽

Cited By ~ 4

Author(s):

Nathaniel Jenkins ◽

Terry Housh ◽

Samuel Buckner ◽

Haley Bergstrom ◽

Kristen Cochrane ◽

...

Keyword(s):

Resistance Exercise ◽

Muscle Activation ◽

Low Load

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

Perceptual and Motor Skills ◽

10.2466/pms.2002.94.3c.1157 ◽

2002 ◽

Vol 94 (3_suppl) ◽

pp. 1157-1167 ◽

Cited By ~ 2

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.

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Strength training the free limb attenuates strength loss during unilateral immobilization

Journal of Applied Physiology ◽

10.1152/japplphysiol.91331.2008 ◽

2009 ◽

Vol 106 (3) ◽

pp. 830-836 ◽

Cited By ~ 50

Author(s):

Jonathan P. Farthing ◽

Joel R. Krentz ◽

Charlene R. A. Magnus

Keyword(s):

Strength Training ◽

Muscle Activation ◽

Muscle Thickness ◽

Strength Loss ◽

Peak Torque ◽

Ulnar Deviation ◽

Before And After ◽

Cross Education ◽

The Right ◽

Arm Strength

The objective was to determine if strength training the free limb during a 3-wk period of unilateral immobilization attenuates strength loss in the immobilized limb through cross-education. Thirty right-handed participants were assigned to three groups. One group ( n = 10) wore a cast and trained the free arm (Cast-Train). A second group ( n = 10) wore a cast and did not train (Cast). A third group ( n = 10) received no treatment (control). Casts were applied to the nondominant (left) wrist and hand by a physician. Strength training was maximal isometric ulnar deviation (right hand) 5 days/wk. Peak torque (dynamometer), electromyography (EMG), and muscle thickness (ultrasound) were assessed in both arms before and after the intervention. Cast-Train improved right arm strength [14.3 (SD 5.0) to 17.7 (SD 4.8) N·m; P < 0.05] with no significant muscle hypertrophy [3.73 (SD 0.43) to 3.84 (SD 0.52) cm; P = 0.09]. The immobilized arm of Cast-Train did not change in strength [13.9 (SD 4.3) to 14.2 (SD 4.6) N·m] or muscle thickness [3.61 (SD 0.51) to 3.57 (SD 0.43) cm]. The immobilized arm of Cast decreased in strength [12.2 (SD 3.8) to 10.4 (SD 2.5) N·m; P < 0.05] and muscle thickness [3.47 (SD 0.59) to 3.32 (SD 0.55) cm; P < 0.05]. Control showed no changes in the right arm [strength: 15.3 (SD 6.1) to 14.3 (SD 5.8) N·m; muscle thickness: 3.57 (SD 0.68) to 3.52 (SD 0.75) cm] or left arm [strength: 14.5 (SD 5.3) to 13.7 (SD 6.1) N·m; muscle thickness: 3.55 (SD 0.77) to 3.51 (SD 0.70) cm]. Agonist muscle activation remained unchanged after the intervention for both arms [right: 302 (SD 188) to 314 (SD 176) μV; left: 261 (SD 139) to 288 (SD 151) μV] with no group differences. Strength training of the free limb attenuated strength loss in the immobilized limb during unilateral immobilization. Strength training may have prevented muscle atrophy in the immobilized limb.

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

Applied Physiology Nutrition and Metabolism ◽

10.1139/h09-020 ◽

2009 ◽

Vol 34 (4) ◽

pp. 609-615 ◽

Cited By ~ 42

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.

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Force production and muscle activation during partial vs. full range of motion in Paralympic Powerlifting

PLoS ONE ◽

10.1371/journal.pone.0257810 ◽

2021 ◽

Vol 16 (10) ◽

pp. e0257810

Author(s):

Tanise Pires Mendonça ◽

Felipe José Aidar ◽

Dihogo Gama Matos ◽

Raphael Fabrício Souza ◽

Anderson Carlos Marçal ◽

...

Keyword(s):

Range Of Motion ◽

Muscle Activation ◽

Isometric Force ◽

Full Range ◽

Pectoralis Major Muscle ◽

National Level ◽

Force Production ◽

Muscle Thickness ◽

Pectoralis Major ◽

Post Exercise

Paralympic Powerlifting is a sport in which the strength of the upper limbs is assessed through bench press performance in an adapted specific bench. It is therefore essential to optimize training methods to maximize this performance. The aim of the present study was to compare force production and muscle activation involved in partial vs. full range of motion (ROM) training in Paralympic Powerlifting. Twelve male athletes of elite national level in Paralympic Powerlifting participated in the study (28.60 ± 7.60 years of age, 71.80 ± 17.90 kg of body mass). The athletes performed five sets of 5RM (repetition maximum), either with 90% of 1RM in full ROM or with a load of 130% 1RM in partial ROM. All subjects underwent both exercise conditions in consecutive weeks. Order assignment in the first week was random and counterbalanced. Fatigue index (FI), Maximum Isometric Force (MIF), Time to MIF (Time) and rate of force development (RFD) were determined by a force sensor. Muscle thickness was obtained using ultrasound images. All measures were taken pre- and post-training. Additionally, electromyographic signal (EMG) was evaluated in the last set of each exercise condition. Post-exercise fatigue was higher with full ROM as well as loss of MIF. Full ROM also induced greater. EMG showed greater activation of the Clavicular portion and Sternal portion of pectoralis major muscle and lower in the anterior portion of deltoid muscle when full ROM was performed. Muscle thickness of the pectoralis major muscle increased post-exercise. We concluded that training with partial ROM enables higher workloads with lower loss of muscle function.

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Fused Ultrasound And Electromyography-Driven Neuromuscular Model To Improve Plantarflexion Moment Prediction Across Walking Speeds

10.21203/rs.3.rs-1136552/v1 ◽

2022 ◽

Author(s):

Qiang Zhang ◽

Natalie Fragnito ◽

Jason R. Franz ◽

Nitin Sharma

Keyword(s):

Prediction Accuracy ◽

Muscle Activation ◽

Control Strategies ◽

Muscle Thickness ◽

Semg Signal ◽

Prediction Ability ◽

Imaging Results ◽

Speed Mode ◽

Neurological Injuries ◽

Walking Speeds

Abstract Background: Improving the prediction ability of a human-machine interface (HMI) is critical to accomplish a bio-inspired or model-based control strategy for rehabilitation interventions, which are of increased interest to assist limb function post neurological injuries. A fundamental role of the HMI is to accurately predict human intent by mapping signals from a mechanical sensor or surface electromyography (sEMG) sensor. These sensors are limited to measuring the resulting limb force or movement or the neural signal evoking the force. As the intermediate mapping in the HMI also depends on muscle contractility, a motivation exists to include architectural features of the muscle as surrogates of dynamic muscle movement, thus further improving the HMI's prediction accuracy. Objective: The purpose of this study is to investigate a non-invasive sEMG and ultrasound (US) imaging-driven Hill-type neuromuscular model (HNM) for net ankle joint plantarflexion moment prediction. We hypothesize that the fusion of signals from sEMG and US imaging results in a more accurate net plantarflexion moment prediction than sole sEMG or US imaging. Methods: Ten young non-disabled participants walked on a treadmill at speeds of 0.50, 0.75, 1.00, 1.25, and 1.50 m/s. The proposed HNM consists of two muscle-tendon units. The muscle activation for each unit was calculated as a weighted summation of the normalized sEMG signal and normalized muscle thickness signal from US imaging. The HNM calibration was performed under both single-speed mode and inter-speed mode, and then the calibrated HNM was validated across all walking speeds. Results: On average, the normalized moment prediction root mean square error was reduced by 14.58 % (p = 0.012) and 36.79 % (p < 0.001) with the proposed HNM when compared to sEMG-driven and US imaging-driven HNMs, respectively. Also, the calibrated models with data from the inter-speed mode were more robust than those from single-speed modes for the moment prediction.Conclusions: The proposed sEMG-US imaging-driven HNM can significantly improve the net plantarflexion moment prediction accuracy across multiple walking speeds. The findings imply that the proposed HNM can be potentially used in bio-inspired control strategies for rehabilitative devices due to its superior prediction.

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A novel gravity-induced blood flow restriction model augments ACC phosphorylation and PGC-1α mRNA in human skeletal muscle following aerobic exercise: a randomized crossover study

Applied Physiology Nutrition and Metabolism ◽

10.1139/apnm-2019-0641 ◽

2020 ◽

Vol 45 (6) ◽

pp. 641-649 ◽

Cited By ~ 2

Author(s):

Nicholas Preobrazenski ◽

Hashim Islam ◽

Patrick J. Drouin ◽

Jacob T. Bonafiglia ◽

Michael E. Tschakovsky ◽

...

Keyword(s):

Blood Flow ◽

Aerobic Exercise ◽

Messenger Rna ◽

Muscle Activation ◽

Peak Oxygen Uptake ◽

Work Rate ◽

Muscle Oxygenation ◽

Flow Restriction ◽

Acetyl Coenzyme A Carboxylase

This study tested the hypothesis that a novel, gravity-induced blood flow restricted (BFR) aerobic exercise (AE) model will result in greater activation of the AMPK–PGC-1α pathway compared with work rate-matched non-BFR. Thirteen healthy males (age: 22.4 ± 3.0 years; peak oxygen uptake: 42.4 ± 7.3 mL/(kg·min)) completed two 30-min work rate-matched bouts of cycling performed with their legs below (CTL) and above their heart (BFR) at ∼2 weeks apart. Muscle biopsies were taken before, immediately, and 3 h after exercise. Blood was drawn before and immediately after exercise. Our novel gravity-induced BFR model led to less muscle oxygenation during BFR compared with CTL (O2Hb: p = 0.01; HHb: p < 0.01) and no difference in muscle activation (p = 0.53). Plasma epinephrine increased following both BFR and CTL (p < 0.01); however, only norepinephrine increased more following BFR (p < 0.01). PGC-1α messenger RNA (mRNA) increased more following BFR (∼6-fold) compared with CTL (∼4-fold; p = 0.036). VEGFA mRNA increased (p < 0.01) similarly following BFR and CTL (p = 0.21), and HIF-1α mRNA did not increase following either condition (p = 0.21). Phosphorylated acetyl-coenzyme A carboxylase (ACC) increased more following BFR (p < 0.035) whereas p-PKA substrates, p-p38 MAPK, and acetyl-p53 increased (p < 0.05) similarly following both conditions (p > 0.05). In conclusion, gravity-induced BFR is a viable BFR model that demonstrated an important role of AMPK signalling on augmenting PGC-1α mRNA. Novelty Gravity-induced BFR AE reduced muscle oxygenation without impacting muscle activation, advancing gravity-induced BFR as a simple, inexpensive BFR model. Gravity-induced BFR increased PGC-1α mRNA and ACC phosphorylation more than work rate-matched non-BFR AE. This is the first BFR AE study to concurrently measure blood catecholamines, muscle activation, and muscle oxygenation.

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