Index Finger Muscle Fatigue and Pistol Firing Failure

2019 ◽  
Vol 61 (7) ◽  
pp. 1066-1076
Author(s):  
Kai Nestler ◽  
Ulrich Rohde ◽  
Alexander Witzki ◽  
Stephan Waldeck ◽  
Benjamin Becker ◽  
...  
Keyword(s):  
Muscle Fatigue ◽  
Index Finger ◽  
Repetitive Firing ◽  
Maximum Voluntary Isometric Contraction ◽  
Task Failure ◽  
Single Action ◽  
Before And After ◽  
Trigger Mode ◽  
New Perspective ◽  
Marksmanship Training

Objective: The aim of this study was to analyze finger strength and effects of muscle fatigue on the ability to shoot. Background: The finger and hand muscles of soldiers are subject to high loads. For example, the trigger pull of military pistols can amount up to 58 N (≈6 kg) and could cause muscle fatigue in the trigger finger. For soldiers, however, maintaining the ability to shoot is essential for self-defense and survival. Method: The marksmanship training of 30 German soldiers (15 female) ages 18 to 40 years was evaluated. Three consecutive exercises with a total of 60 rounds were fired from target ranges of 5 and 10 m, equally using a single-action and double-action trigger mode. Maximum voluntary isometric contraction of the index finger (MVCIF) was measured before and after each of the three firing exercises. Results: Shooting reduced MVCIF in female (88.2 ± 15.8 N to 67.3 ± 17.7 N, p < .001) and male soldiers (145.8 ± 21.7 N to 112.7 ± 26.6 N, p < .001). Of the 30 subjects, 23 were unable to shoot due to fatigue, including 15 of 15 female soldiers. The higher MVCIF was at rest, the less commonly ( r = .73, p < .001) and the later ( r = 0.82, p < .001) task failure occurred. Two intermissions of approximately 6 min did not suffice for a significant recovery. Conclusion: Excessive trigger pull weight causes muscle fatigue of the index finger and can ultimately lead to task failure during pistol marksmanship training. Short breaks are insufficient for the recovery of finger muscles. Application: This study presents a new perspective on ideal trigger pull weight, which should be carefully considered by manufacturers to allow repetitive firing and simultaneously ensure safe handling.

Comparison of neuromuscular adjustments associated with sustained isometric contractions of four different muscle groups

2013 ◽  
Vol 114 (10) ◽  
pp. 1426-1434 ◽  
Author(s):  
Daria Neyroud ◽  
Jennifer Rüttimann ◽  
Anne F. Mannion ◽  
Guillaume Y. Millet ◽  
Nicola A. Maffiuletti ◽  
...  
Keyword(s):  
Muscle Fatigue ◽  
Upper Limb ◽  
Voluntary Contraction ◽  
Voluntary Activation ◽  
Knee Extensors ◽  
Elbow Flexors ◽  
Plantar Flexors ◽  
Task Failure ◽  
Before And After ◽  
Muscle Groups

The extent and characteristics of muscle fatigue of different muscle groups when subjected to a similar fatiguing task may differ. Thirteen healthy young men performed sustained contractions at 50% maximal voluntary contraction (MVC) force until task failure, with four different muscle groups, over two sessions. Per session, one upper limb and one lower limb muscle group were tested (knee extensors and thumb adductor, or plantar and elbow flexors). Changes in voluntary activation level and contractile properties were derived from doublet responses evoked during and after MVCs before and after exercise. Time to task failure differed ( P < 0.05) between muscle groups (220 ± 64 s for plantar flexors, 114 ± 27 s for thumb adductor, 77 ± 25 s for knee extensors, and 72 ± 14 s for elbow flexors). MVC force loss immediately after voluntary task failure was similar (−30 ± 11% for plantar flexors, −37 ± 13% for thumb adductor, −34 ± 15% for knee extensors, and −40 ± 12% for elbow flexors, P > 0.05). Voluntary activation was decreased for plantar flexors only (from 95 ± 5% to 82 ± 9%, P < 0.05). Potentiated evoked doublet amplitude was more depressed for upper limb muscles (−59.3 ± 14.7% for elbow flexors and −60.1 ± 24.1% for thumb adductor, P < 0.05) than for knee extensors (−28 ± 15%, P < 0.05); no reduction was found in plantar flexors (−7 ± 12%, P > 0.05). In conclusion, despite different times to task failure when sustaining an isometric contraction at 50% MVC force for as long as possible, diverse muscle groups present similar loss of MVC force after task failure. Thus the extent of muscle fatigue is not affected by time to task failure, whereas this latter determines the etiology of fatigue.

scholarly journals PARE0007 PATIENT AND PUBLIC INVOLVEMENT IN CLINICAL TRIAL DESIGN

2020 ◽  
Vol 79 (Suppl 1) ◽  
pp. 1289.1-1290
Author(s):  
S. De Souza ◽  
R. Williams ◽  
E. Johansson ◽  
C. Zabalan ◽  
T. Esterine ◽  
...  
Keyword(s):  
At Risk ◽  
Lived Experience ◽  
Public Involvement ◽  
Clinical Trial Design ◽  
Patient And Public Involvement ◽  
Face To Face ◽  
Before And After ◽  
Extensive Consultation ◽  
New Perspective ◽  
The Eu

Background:Patient and public involvement (PPI) is gaining increasing recognition as important in ensuring research is relevant and acceptable to participants. Rheuma Tolerance for Cure (RTCure) is a 5 year international collaboration between academia and industry; focusing on earlier detection and prevention of rheumatoid arthritis (RA) through the use of immune-tolerising treatments.Objectives:To bring lived experience and insight into scientific discussions; and to evolve collaboration between lay representatives and academia/industry.Methods:9 Patient Research Partners (PRPs) from 5 European countries were recruited via the EULAR PARE Network and institutions within the RTCure Consortium (8 PRPs with RA and 1 ‘at risk’). They were asked to enter into a legal agreement with the Consortium. PRPs participated in teleconferences (TCs) and were invited to attend face-to-face (F2F) meetings at least annually. Requests for input/feedback were sent from researchers to PRPs via the project’s Patient Engagement Expert [SK].Results:PRP involvement has given researchers and industry partners a new perspective on patient priorities, and focused thought on the ethics of recruitment for and participation in clinical trials of people ‘at risk’ of developing RA. PRPs have helped define the target populations, given their thoughts on what types of treatments are acceptable to people ‘at risk’ and have aided the development of a survey (sent to EULAR PARE members) regarding the use of animal models in biomedical research. Positive informal feedback has been received from researchers and industry regarding the contribution of PRPs to the ongoing project (formal evaluation of PPI in RTCure will be carried out in 2020 and at the project end in 2022).Challenges:Legal agreements- Many PRPs refused to sign the Consortium’s complex PRP Agreement; feeling it unnecessary, incomprehensible and inequitable. After extensive consultation with various parties (including EULAR and the Innovative Medicines Initiative) no similar contract was found. Views for its requirement even varied between legal experts. After 2 years of intense discussion, a simple non-disclosure agreement was agreed upon. Ideally any contract, if required, should be approved prior to project onset.Meeting logistics- Other improvements identified were to locate the meeting venue and accommodation on the same site to minimise travel, and to make it easier for PRPs to take breaks when required. This also facilitates informal discussions and patient inclusivity. We now have agreed a policy to fund PRPs extra nights before and after meetings, and to bring a carer if needed.Enabling understanding– Future annual meetings will start with a F2F meeting between PRPs and Work Package Leads. Researchers will be encouraged to start presentations with a summary slide in lay language. Additionally, an RTCure Glossary is in development.Enabling participation– SK will provide monthly project updates and PRP TCs will be held in the evening (as some PRPs remain employed). PRPs will be invited to all project TCs and F2F meetings. Recruitment is underway to increase the number of ‘at risk’ PRPs as their viewpoint is vital to this study.Conclusion:Currently PPI in RTCure is an ongoing mutual learning process. Universal guidance regarding what types of contracts are needed for PPI would be useful. Communication, trust and fruitful discussions have evolved through F2F meetings (both formal and informal) between PRPs, academia and industry. It is important that all parties can be open with each other in order to make PPI more meaningful.Acknowledgments:This work has received support from the EU/EFPIA Innovative Medicines Initiative 2 Joint Undertaking RTCure grant number 777357.Disclosure of Interests:Savia de Souza: None declared, Ruth Williams: None declared, Eva Johansson: None declared, Codruta Zabalan: None declared, Tom Esterine: None declared, Margôt Bakkers: None declared, Wolfgang Roth: None declared, Neil Mc Carthy: None declared, Meryll Blake: None declared, Susanne Karlfeldt: None declared, Martina Johannesson: None declared, Karim Raza Grant/research support from: KR has received research funding from AbbVie and Pfizer, Consultant of: KR has received honoraria and/or consultancy fees from AbbVie, Sanofi, Lilly, Bristol-Myers Squibb, UCB, Pfizer, Janssen and Roche Chugai, Speakers bureau: KR has received honoraria and/or consultancy fees from AbbVie, Sanofi, Lilly, Bristol-Myers Squibb, UCB, Pfizer, Janssen and Roche Chugai

scholarly journals Task failure from inspiratory resistive loaded breathing: a role for inspiratory muscle fatigue?

2003 ◽  
Vol 90 (3-4) ◽  
pp. 405-410 ◽  
Author(s):  
Markus Rohrbach ◽  
Claudio Perret ◽  
Bengt Kayser ◽  
Urs Boutellier ◽  
Christina M. Spengler
Keyword(s):  
Muscle Fatigue ◽  
Inspiratory Muscle ◽  
Task Failure ◽  
Loaded Breathing ◽  
Inspiratory Muscle Fatigue

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.

China’s Soft Power in Pakistan: The Representation of the China–Pakistan Economic Corridor in Local Newspapers

2021 ◽  
Vol 13 (04) ◽  
pp. 5-18
Author(s):  
Zahid Shahab AHMED ◽  
Ahsan HANIF ◽  
Baogang HE
Keyword(s):  
Soft Power ◽  
News Coverage ◽  
Belt And Road Initiative ◽  
Local Newspapers ◽  
Newspaper Reporting ◽  
Before And After ◽  
Belt And Road ◽  
New Perspective ◽  
The Belt And Road

This article conducts a case study of China’s influence on Pakistan by collecting and analysing news coverage from two prominent English and Urdu newspapers in Pakistan for a five-year period between 2013 and 2018. It compares the changes in newspaper reporting before and after the launch of the China–Pakistan Economic Corridor (CPEC) in 2015. Analysis has shown a significant increase in positive reporting on the CPEC and China. The case of Pakistan is representative of its recognition of China’s soft power in a developing country, thus offering a new perspective on China’s goodwill vis-à-vis the Belt and Road Initiative.

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.

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.

scholarly journals Comparison of Latanoprost/Timolol with Carbonic Anhydrase Inhibitor and Dorzolamide/Timolol with Prostaglandin Analog in the Treatment of Glaucoma

2014 ◽  
Vol 2014 ◽  
pp. 1-5 ◽  
Author(s):  
Kenji Inoue ◽  
Shoichi Soeda ◽  
Goji Tomita
Keyword(s):  
Visual Field ◽  
Fixed Combination ◽  
Open Angle Glaucoma ◽  
Field Testing ◽  
Mean Deviation ◽  
Single Action ◽  
Before And After ◽  
Group 2 ◽  
Concomitant Medications ◽  
Medication Changes

Purpose.We retrospectively reviewed medical records of glaucoma patients to investigate how switching medications may affect intraocular pressure (IOP) management. Three concomitant medications were changed to two medications: one combination drop and one single-action drop. Associated adverse effects were also examined.Subjects and Methods.A total of 112 patients with primary open-angle glaucoma or ocular hypertension were examined. All patients were concomitantly using a prostaglandin (PG) analog, aβ-blocker, and a carbonic anhydrate inhibitor (CAI). Fifty-five patients began using latanoprost (PG analog)/timolol (β-blocker) fixed-combination (LTFC) drops and a CAI (group 1), and 57 patients began using dorzolamide (CAI)/timolol fixed-combination (DTFC) drops and a PG analog (group 2). The IOP was measured every 6 months for 2 years following medication changes. Changes in visual field mean deviation (MD) and medication discontinuations were also examined.Results.There were no significant differences in IOP or MD values before and after medication changes in either group. The proportion of medication discontinuations, uncontrolled IOP, and adverse reactions was similar in both groups.Conclusion.Switching patients from multiple single-action medications to combination medications was not associated with changes in IOP, visual field testing results, or adverse event frequency.

scholarly journals Sex in Stencil Novels Case Study: Readers' Reception of Enny Arrow's Stencil Novel in Surakarta

2021 ◽  
Vol 04 (01) ◽  
Author(s):  
Ariska Puspita Anggraini ◽  
Keyword(s):  
Data Analysis ◽  
Psychological Factors ◽  
Reception Theory ◽  
The Novel ◽  
Social Psychological ◽  
Modern Humans ◽  
Erotic Literature ◽  
Before And After ◽  
New Perspective

The phenomenon of sex has always been novel in every era. In Indonesia, for example, Enny Arrow’s stencil novel has been circulating, which has been named as a legend of Indonesian erotic literature. Along with the development of technology, the existence of stencil novels was replaced by DVDs or VCDs, which then continued with the emergence of various sites providing access to pornography. This difference in phenomena certainly makes the meaning of sex for each individual different. This research will analyze the meaning of sex in the stencil novel by Enny Arrow in the eyes of millennial men. The data analysis will focus on social psychological factors using Normand Holland’s literary reception theory. From the data analysis, it can be concluded that there are different views on sexual relations before and after reading the novel. This research is expected to provide a new perspective on the picture of sexuality for modern humans.

Navicular Drop Before and After Fatigue of the Ankle Invertor Muscles

2013 ◽  
Vol 18 (6) ◽  
pp. 36-39 ◽  
Author(s):  
Fredrick Anthony Gardin ◽  
David Middlemas ◽  
Jennifer L. Williams ◽  
Steven Leigh ◽  
Rob R. Horn
Keyword(s):  
Muscle Fatigue ◽  
Correlation Coefficients ◽  
Standing Position ◽  
Medial Longitudinal Arch ◽  
Intra Class Correlation ◽  
College Age ◽  
Navicular Drop ◽  
Main Effect ◽  
Before And After ◽  
Good Internal Consistency

Context:Navicular drop is widely believed to be an indicator of elevated susceptibility to pronation-related injuries, which may be increased by fatigue in the muscles that dynamically support the medial longitudinal arch.Objective:The purpose of this study was to evaluate navicular drop before and after fatigue of the ankle invertor muscles among individuals with different foot types.Participants:20 male and 16 female recreationally active, college-age volunteers (20.03 ± 1.48 years of age).Methods:Navicular drop was measured before and after inducing fatigue in the ankle invertor muscles. Participants’ foot types were classified as high-arch, neutral, or low-arch.Results:There was no interaction between foot type and trial, and no main effect for trial. A main effect for foot type was significant (p = .001). Intra-class correlation coefficients for prefatigue and postfatigue measurements indicated good internal consistency.Conclusion:Our fndings failed to provide any evidence to support the existence of a relationship between ankle invertor muscle fatigue and static measurements of change in navicular height from a sitting to standing position.

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