Trial reportThe Journal of physiology2003
Motor unit recruitment and derecruitment induced by brief increase in contraction amplitude of the human trapezius muscle.
Trial report in The Journal of physiology, 2003. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 26 papers, 1 of them a synthesis that pooled it.
What it found
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The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.
Who cites it
26 citing papers in PubMed, 1 synthesis or guideline pooled it.
- Effects of Blood Flow Restriction Training on Muscular Strength and Hypertrophy in Older Individuals: A Systematic Review and Meta-Analysis.Sports medicine (Auckland, N.Z.) · 2019Pooled it
- Electromyogram and perceived fatigue changes in the trapezius muscle during typewriting and recovery.European journal of applied physiology · 2007Trial
- The influence of contraction amplitude and firing history on spike-triggered averaged trapezius motor unit potentials.The Journal of physiology · 2005Trial
- The effects of resistance exercise with blood flow restriction on muscle performance, muscle mass, and function in older adults: a systematic review.European review of aging and physical activity : official journal of the European Group for Research into Elderly and Physical Activity · 2026Review
- Analysis of motor units with high-density surface electromyography: methodological considerations and physiological significance.European journal of applied physiology · 2026Review
- The role of torso stiffness and prediction in the biomechanics of anxiety: a narrative review.Frontiers in sports and active living · 2024Review
- Electromyographic and mechanomyographic responses of the biceps brachii during concentric and eccentric muscle actions to failure at high and low relative loads.European journal of applied physiology · 2023Article
- Comparison of Physiological Effects Induced by Two Compression Stockings and Regular Socks During Prolonged Standing Work.Human factors · 2023Article
- Spatial Reorganization of Myoelectric Activities in Extensor Digitorum for Sustained Finger Force Production.Sensors (Basel, Switzerland) · 2019Article
- Model-based analysis of fatigued human knee extensors : Effects of isometrically induced fatigue on Hill-type model parameters and ballistic contractions.European journal of applied physiology · 2018Article
- High- and Low-Load Resistance Training: Interpretation and Practical Application of Current Research Findings.Sports medicine (Auckland, N.Z.) · 2017Article
- Variability in spatio-temporal pattern of trapezius activity and coordination of hand-arm muscles during a sustained repetitive dynamic task.Experimental brain research · 2017Article
- Functional connectivity between core and shoulder muscles increases during isometric endurance contractions in judo competitors.European journal of applied physiology · 2015Article
- Fatigue effect on low-frequency force fluctuations and muscular oscillations during rhythmic isometric contraction.PloS one · 2014Article
- Variation of force amplitude and its effects on local fatigue.European journal of applied physiology · 2012Article
- Active biofeedback changes the spatial distribution of upper trapezius muscle activity during computer work.European journal of applied physiology · 2010Article
- Recovery of human motoneurons during rotation.Experimental brain research · 2010Article
- Discharge behaviors of trapezius motor units during exposure to low and high levels of acute psychosocial stress.Journal of clinical neurophysiology : official publication of the American Electroencephalographic Society · 2010Article
- Experimental pain leads to reorganisation of trapezius electromyography during computer work with active and passive pauses.European journal of applied physiology · 2009Article
- Central motor control failure in fibromyalgia: a surface electromyography study.BMC musculoskeletal disorders · 2009Article
Corrections and comments
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Authors and funding
3 authors.
Funding
No grant is acknowledged in the PubMed record.
Abstract
The activity pattern of low-threshold human trapezius motor units was examined in response to brief, voluntary increases in contraction amplitude ('EMG pulse') superimposed on a constant contraction at 4-7 % of the surface electromyographic (EMG) response at maximal voluntary contraction (4-7 % EMGmax). EMG pulses at 15-20 % EMGmax were superimposed every minute on contractions of 5, 10, or 30 min duration. A quadrifilar fine-wire electrode recorded single motor unit activity and a surface electrode recorded simultaneously the surface EMG signal. Low-threshold motor units recruited at the start of the contraction were observed to stop firing while motor units of higher recruitment threshold stayed active. Derecruitment of a motor unit coincided with the end of an EMG pulse. The lowest-threshold motor units showed only brief silent periods. Some motor units with recruitment threshold up to 5 % EMGmax higher than the constant contraction level were recruited during an EMG pulse and kept firing throughout the contraction. Following an EMG pulse, there was a marked reduction in motor unit firing rates upon return of the surface EMG signal to the constant contraction level, outlasting the EMG pulse by 4 s on average. The reduction in firing rates may serve as a trigger to induce derecruitment. We speculate that the silent periods following derecruitment may be due to deactivation of non-inactivating inward current ('plateau potentials'). The firing behaviour of trapezius motor units in these experiments may thus illustrate a mechanism and a control strategy to reduce fatigue of motor units with sustained activity patterns.
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