Errors in Force Generation and Changes in Controlling Patterns Following Agonist Muscle Fatigue

2009 ◽  
Vol 25 (4) ◽  
pp. 293-303 ◽  
Author(s):  
Yi-Ming Huang ◽  
Ya-Ju Chang ◽  
Miao-Ju Hsu ◽  
Chia-Ling Chen ◽  
Chia-Ying Fang ◽  
...  
Keyword(s):  
Muscle Fatigue ◽  
Constant Error ◽  
Antagonist Muscle ◽  
Activation Level ◽  
Before And After ◽  
Agonist And Antagonist ◽  
Common Drive ◽  
The Common ◽  
Possible Cause ◽  
Related Increase

The purpose of this study was to evaluate whether agonist muscle fatigue changed the coactivation time and the co-contraction magnitude of the agonist and antagonist muscle, and if the agonist muscle fatigue produced bias (constant error: CE) and inconsistency (variable error: VE) of the force. Subjects are 10 healthy people and one person with impaired proprioception. EMG and force for fast (0.19 ± 0.06 s) and slow (1.20 ± 0.44 s) targeted isometric dorsiflexions were recorded before and after fatigue of the dorsiflexors. The results revealed that the coactivation time increased after fatigue only in the slow contractions but the co-contraction magnitude did not change. The postfatigue increment of the CE was greater in the fast contractions than in the slow ones. We conclude that the postfatigue compensatory strategy can reduce the fatigue-induced bias. The change of muscles activation level after fatigue might be under the influence of the common drive. Impaired proprioception is a possible cause of the fatigue-related increase in bias and inconsistency.

A comparison of the effects of agonist and antagonist muscle fatigue on performance of rapid movements

1997 ◽  
Vol 76 (1) ◽  
pp. 41-47 ◽  
Author(s):  
Slobodan Jaric ◽  
Sa?a Radovanovic ◽  
Sladjan Milanovic ◽  
Milo? Ljubisavljevic ◽  
Radmila Anastasijevic
Keyword(s):  
Muscle Fatigue ◽  
Antagonist Muscle ◽  
Agonist And Antagonist

scholarly journals Comparison of Agonist and Antagonist Muscle Fatigue on Coactivation and Force Production

2019 ◽  
Vol 51 (Supplement) ◽  
pp. 319
Author(s):  
Cameron S. Mackey ◽  
Jesus A. Hernandez-Sarabia ◽  
Micheal J. Luera ◽  
Alejandra Barrera-Curiel ◽  
Jason M. DeFreitas
Keyword(s):  
Muscle Fatigue ◽  
Force Production ◽  
Antagonist Muscle ◽  
Agonist And Antagonist

Changes in movement final position associated with agonist and antagonist muscle fatigue

1999 ◽  
Vol 80 (5) ◽  
pp. 467-471 ◽  
Author(s):  
Slobodan Jaric ◽  
Suzana Blesic ◽  
Sladjan Milanovic ◽  
Sasa Radovanovic ◽  
Milos Ljubisavljevic ◽  
...  
Keyword(s):  
Muscle Fatigue ◽  
Final Position ◽  
Antagonist Muscle ◽  
Agonist And Antagonist

Efforts to Improve Appropriate Trauma Activation for Patients Transferred to a Level 1 Trauma Center From Outside Hospitals

2020 ◽  
Vol 86 (5) ◽  
pp. 467-475
Author(s):  
Sara Seegert ◽  
Roberta E. Redfern ◽  
Bethany Chapman ◽  
Daniel Benson
Keyword(s):  
Injury Severity ◽  
Trauma Centers ◽  
Activation Level ◽  
American College Of Surgeons ◽  
Before And After ◽  
Trauma Response ◽  
Level 1 ◽  
Transferred Patients ◽  
Trauma Activation ◽  
Level 1 Trauma Center

Trauma centers monitor under- and overtriage rates to comply with American College of Surgeons Committee on Trauma verification requirements. Efforts to maintain acceptable rates are often undertaken as part of quality assurance. The purpose of this project was to improve the institutional undertriage rate by focusing on appropriately triaging patients transferred from outside hospitals (OSHs). Trauma physicians received education and pocket cards outlining injury severity score (ISS) calculation to aid in prospectively estimating ISS for patients transferred from OSHs, and activate the trauma response expected for that score. Under- and overtriage rates before and after the intervention were compared. The postintervention period saw a significant decrease in overall overtriage rate, with simultaneous trend toward lower overall undertriage rate, attributable to the significant reduction in undertriage rate of patients transferred from OSHs. Prospectively estimating ISS to assist in determining trauma activation level shows promise in managing appropriate patient triage. However, questions arose regarding the necessity for full trauma activation for transferred patients, regardless of ISS. It may be necessary to reconsider how patients transferred from OSHs are evaluated. Full trauma activation can be a financial and resource burden, and should not be taken lightly.

Neck muscle fatigue and spatial orientation during stepping in place in humans

2005 ◽  
Vol 99 (1) ◽  
pp. 141-153 ◽  
Author(s):  
Micaela Schmid ◽  
Marco Schieppati
Keyword(s):  
Muscle Fatigue ◽  
Afferent Input ◽  
Neck Muscle ◽  
Median Frequency ◽  
Optoelectronic System ◽  
Neck Proprioception ◽  
Before And After ◽  
Spatial Reference Frame ◽  
Stepping In Place ◽  
Neck Muscle Fatigue

Neck proprioceptive input, as elicited by muscle vibration, can produce destabilizing effects on stance and locomotion. Neck muscle fatigue produces destabilizing effects on stance, too. Our aim was to assess whether neck muscle fatigue can also perturb the orientation in space during a walking task. Direction and amplitude of the path covered during stepping in place were measured in 10 blindfolded subjects, who performed five 30-s stepping trials before and after a 5-min period of isometric dorsal neck muscle contraction against a load. Neck muscle electromyogram amplitude and median frequency during the head extensor effort were used to compute a fatigue index. Head and body kinematics were recorded by an optoelectronic system, and stepping cadence was measured by sensorized insoles. Before the contraction period, subjects normally stepped on the spot or drifted forward. After contraction, some subjects reproduced the same behavior, whereas others reduced their forward progression or even stepped backward. The former subjects showed minimal signs of fatigue and the latter ones marked signs of fatigue, as quantified by the dorsal neck electromyogram index. Head position and cadence were unaffected in either group of subjects. We argue that the abnormal fatigue-induced afferent input originating in the receptors transducing the neck muscle metabolic state can modulate the egocentric spatial reference frame. Notably, the effects of neck muscle fatigue on orientation are opposite to those produced by neck proprioception. The neck represents a complex source of inputs capable of modifying our orientation in space during a locomotor task.

scholarly journals Implementation and Evaluation of a Communication Strategy to Control Ragweed Pollen

2016 ◽  
Vol 5 (1) ◽  
pp. 87
Author(s):  
Celine Plante ◽  
Audrey Smargiassi ◽  
Francine Hubert ◽  
Sophie Goudreau
Keyword(s):  
Fold Increase ◽  
Ambrosia Artemisiifolia ◽  
Communication Strategy ◽  
Ragweed Pollen ◽  
Communication Intervention ◽  
Effective Measure ◽  
Land Owners ◽  
Before And After ◽  
Logistic Regressions ◽  
The Common

The common ragweed (<em>Ambrosia artemisiifolia</em>) is widespread in southwestern areas of Quebec, Canada. It is known to release large quantities of pollen from July through September, triggering allergic reactions such as rhinitis and generating significant costs for public health. The objective of this study was to implement and evaluate a communication intervention aimed at decreasing ragweed pollen. Selected lands with potential ragweed presence were visited twice, before and after the intervention, on three seasons in the East of the Montreal Island, Quebec. At the first visit done in 2010, 2011, and 2012, ragweed plots were located and measured; at the second visit in 2012, the measures were redone. Various numbers of communications were sent to owners of ragweed-infested lands that included explanations of health impacts of ragweed pollen and the importance of mowing. Mixed logistic regressions were used to test the effect of the number of communications on the mow. In the group that received four notices, a statistically significant three-fold increase in the proportion of land owners that had cut ragweed plots (OR = 3.20; 95 %CI: 1.16-8.84) was noted, compared to the group that received only one notice. For owners of vacant lands, the effect was somewhat more pronounced (OR = 3.82; 95%CI: 1.23-11.67). Nonetheless, the change from one to three communications showed no increase of mowing. In conclusion, the results of the present study suggest that communications and reminders of the importance of ragweed cut to landowners could be an effective measure to limit ragweed pollen.

Reversal of muscle fatigue during 16 h of heavy intermittent cycle exercise

2004 ◽  
Vol 97 (6) ◽  
pp. 2166-2175 ◽  
Author(s):  
H. J. Green ◽  
T. A. Duhamel ◽  
S. Ferth ◽  
G. P. Holloway ◽  
M. M. Thomas ◽  
...  
Keyword(s):  
Oxygen Consumption ◽  
Muscle Fatigue ◽  
Intermittent Exercise ◽  
Low Frequency ◽  
Quadriceps Muscle ◽  
Stimulation Frequency ◽  
Peak Oxygen Consumption ◽  
Force Frequency ◽  
Reduction In Force ◽  
Before And After

This study examined the effects of extended sessions of heavy intermittent exercise on quadriceps muscle fatigue and weakness. Twelve untrained volunteers (10 men and 2 women), with a peak oxygen consumption of 44.3 ± 2.3 ml·kg−1·min−1, exercised at ∼91% peak oxygen consumption for 6 min once per hour for 16 h. Muscle isometric properties assessed before and after selected repetitions (R1, R2, R4, R7, R12, and R15) were used to quantitate fatigue (before vs. after repetitions) and weakness (before vs. before repetitions). Muscle fatigue at R1 was indicated by reductions ( P < 0.05) in peak twitch force (135 ± 13 vs. 106 ± 11 N) and by a reduction ( P < 0.05) in the force-frequency response, which ranged between ∼53% at 10 Hz (113 ± 12 vs. 52.6 ± 7.4 N) and ∼17% at 50 Hz (324 ± 27 vs. 270 ± 30 N). No recovery of force, regardless of stimulation frequency, was observed during the 54 min between R1 and R2. At R2 and for all subsequent repetitions, no reduction in force, regardless of stimulation frequency, was generally found after the exercise. The only exception was for R2, where, at 20 Hz, force was reduced ( P < 0.05) by 18%. At R15, force before repetitions for high frequencies (i.e., 100 Hz) returned to R1 (333 ± 29 vs. 324 ± 27 N), whereas force at low frequency (i.e., 10 Hz) was only partially ( P < 0.05) recovered (113 ± 12 vs. 70 ± 6.6 N). It is concluded that multiple sessions of heavy exercise can reverse the fatigue noted early and reduce or eliminate weakness depending on the frequency of stimulation.

Failure of normal development of central drive to ankle dorsiflexors relates to gait deficits in children with cerebral palsy

2013 ◽  
Vol 109 (3) ◽  
pp. 625-639 ◽  
Author(s):  
Tue Hvass Petersen ◽  
Simon F. Farmer ◽  
Mette Kliim-Due ◽  
Jens Bo Nielsen
Keyword(s):  
Cerebral Palsy ◽  
Frequency Domain ◽  
Frequency Domain Analysis ◽  
Response To Therapy ◽  
Typically Developing ◽  
Control Subjects ◽  
Children With Cerebral Palsy ◽  
Common Drive ◽  
The Common ◽  
Central Drive

Neurophysiological markers of the central control of gait in children with cerebral palsy (CP) are used to assess developmental response to therapy. We measured the central common drive to a leg muscle in children with CP. We recorded electromyograms (EMGs) from the tibialis anterior (TA) muscle of 40 children with hemiplegic CP and 42 typically developing age-matched controls during static dorsiflexion of the ankle and during the swing phase of treadmill walking. The common drive to TA motoneurons was identified through time- and frequency-domain cross-correlation methods. In control subjects, the common drive consists of frequencies between 1 and 60 Hz with peaks at beta (15–25 Hz) and gamma (30–45 Hz) frequencies known to be caused by activity within sensorimotor cortex networks: this drive to motoneurons strengthens during childhood. Similar to this drive in control subjects, this drive to the least affected TA in the CP children tended to strengthen with age, although compared with that in the control subjects, it was slightly weaker. For CP subjects of all ages, the most affected TA muscle common drive was markedly reduced compared with that of their least affected muscle as well as that of controls. These differences between the least and most affected TA muscles were unrelated to differences in the magnitude of EMG in the two muscles but positively correlated with ankle dorsiflexion velocity and joint angle during gait. Time- and frequency-domain analysis of ongoing EMG recruited during behaviorally relevant lower limb tasks provides a noninvasive and important measure of the central drive to motoneurons in subjects with CP.

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