Evidence based research that looks into factors that contribute to muscular fatigue. Answers the questions, does age, gender, or nervous system play a role in muscular fatigue.
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Age, Physical Activity and Sex: Characteristics That Contribute To Muscular Fatigue
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Evidence Based Practice Research
Presentation
Rumy Petkov ATS
Winona State University
Winona, Minnesota
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INTRODUCTION
The diversity of measures, that have been used to quantify
fatigue, the specificity of the impairments that cause fatigue and
the lack of knowledge on the mechanism that limit performance
Due to the specificity of the impairments that occur during fatiguing
contractions, there are no general answers to such questions as:
Are older adults more fatigable than young adults?
Are women less fatigable than men?
Can the nervous system sustain an adequate activation of muscle
during fatiguing contractions?
Are there differences between muscles?
Dr. David Altchek from the Hospital for Special Surgery in New
York, “From an intuitive standpoint, the connection between tired
athletes and injuries appears obvious, however I see no
relationship between the two.”
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INTRODUCTION
This topic is crucial because…
It will produce better Athletic Training practice by understanding how
much is to much
Muscle fatigue is not the point of task failure or the moment when the
muscles become exhausted
Decline in a person's ability to exert force
Muscle fatigue, it seems,
can refer to a motor deficit
a perception or a decline in mental function
it can describe the gradual decrease in the force capacity of
muscle or the endpoint of a sustained activity
it can be measured as a reduction in muscle force
a change in electromyographic activity or an exhaustion of
contractile function
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SUMMARY OF FINDINGS
Open chain methods (Functional
Running
Squatting
Jumping
Individual/Combination
Closed chain methods
Weight training machines
Set number of repetitions at % of 1 rep max
Isokinetic Dynamometry
Experimental Design
SPSS
EMG testing
• Pearson product-moment
• Correlation Coefficient
Repeated measures Anova
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SUMMARY OF FINDINGS
Differences in fatigability between young and old
adults
Differences in fatigability between young and old
adults
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SUMMARY OF FINDINGS
Another example on the specificity of the impairments during
fatiguing contractions involves the sex difference that is often
observed during such tasks
Women are usually able to sustain a contraction for a longer
duration, especially at lower contraction intensities but not
maximal contractions
As the supply and demand of ATP is altered during the
occlusion of blood flow, the lower rate of fatigue development
observed in women during intermittent contractions may be
attributable to a sex difference in the relative contributions of
the metabolic pathways that supply ATP during fatiguing
contractions
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SUMMARY OF FINDINGS
The magnitude of the decline in voluntary activation during
fatiguing contractions ranges from minimal to substantial
These studies suggest that some of the fatigue experienced
during repetitive maximal contractions and long-duration
submaximal contractions can be caused by an inadequate
activation of muscle by the nervous system
Furthermore, the insufficiency of the activation can be
exacerbated by such conditions as a decline in the levels of
blood glucose and exercise in hot environments
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SUMMARY OF FINDINGS
Decreases in MVC torque and voluntary
activation during a fatiguing contraction
Decreases in MVC torque and voluntary
activation during a fatiguing contraction
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SUMMARY OF FINDINGS
Eccentric hamstrings strength decreased as a function of time and
after the halftime interval. This finding indicates a greater risk of
injuries at these specific times, especially for explosive
movements, in accordance with epidemiologic observations.
Fatigue can affect motor control with losses in proprioception
visualized by a significantly different arm path while throwing a
baseball. Like pain, fatigue is generally difficult to quantify because
it is a subjective measure that varies among persons.
Therefore, pitch counts, ball velocity, ball location, pitching
mechanics, and strength may be better guides in determining
fatigue.
Fatigue-induced decrease in neuromuscular function with a
corresponding increase in Tibial Translation probably contributes
to the higher incidence of ACL injuries in women.
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CLINICAL BOTTOM LINE
Task failure affords a strategy to identify the functional
significance of physiological adjustments that occur during
fatiguing contractions
Higher injury risk in the fatigued player during explosive
movements such as sprinting is consistent with the increased
fatigue effect
Fatigue should be considered in the rehabilitation process to
guide decisions on return to activities
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REFERENCES
ABC 7 Health News (2010,). Year round sports lead to overuse injuries | Retrieved September 19, 2013
Adlersberg J, Year round sports lead to overuse injuries.
http://abclocal.go.com/kabc/story?section=news/health&id=7525663. Assessed September 17,
2013
Aoki , K., Nakao, A., Adachi, T., Matsui , Y., & Miyakawa, S. (2012). Pilot study: Effects of drinking
hydrogen-rich water on muscle fatigue caused by acute exercise in elite athletes. Med. Gas Res, 2(1), 12.
Behrens M, Mau-Moeller A, Wassermann F, Bruhn S (2013) Effect of Fatigue on Hamstring Reflex
Responses and Posterior-Anterior Tibial Translation in Men and Women. PLoS ONE 8(2): e56988
Demougeot L, Papaxanthis C. Muscle fatigue affects mental simulation of action. J Neurosci.
2011;31(29):10712-20.
Dugan SA, Frontera WR. Muscle fatigue and muscle injury. Phys Med Rehabil Clin N Am. 2000;11(2):385-
403.
Edouard P, Bankolé C, Calmels P, Beguin L, Degache F. Isokinetic rotator muscles fatigue in
glenohumeral joint instability before and after Latarjet surgery: a pilot prospective study. Scand J Med Sci
Sports. 2013;23(2):e74-80.
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REFERENCES
Enoka R, Duchateau J, Muscle fatigue: what, why and how it influences muscle function. Journal of
Physiology. 586.1 (2008) pp 11–23
Escamilla R, Barrentine S, Fleisig G, et al. Pitching Biomechanics as a Pitcher Approaches Muscular Fatigue
During a Simulated Baseball Game. The American Journal of Sports Medicine. January 2007; 35: 1
Greig M, Siegler J, Soccer-Specific Fatigue and Eccentric Hamstrings Muscle Strength, National Athletic
Training Association, Mar-Apr 2009; Volume 44(2)
Humphrey L, Arbuckle R, Mease P, Williams DA, Samsoe BD, Gilbert C. Fatigue in fibromyalgia: a conceptual
model informed by patient interviews. BMC Musculoskelet Disord. 2010;11(1):216.
Pelton K, Pesca M, Fatigue and ACL Injuries.
http://www.basketballprospectus.com/article.php?articleid=2297, Assessed on September 17, 2013
Rimmer P, Muscular Fatigue: Methods for Assessing fatigue and Implications for Anterior Cruciate Ligament
(ACL) Injury. [Powepoint]. Cardiff University.
Woldstad J.C., Brace Tony, Musculoskeletal Disorders [Powerpoint]. Corvallis, Oregon: Oregon State
Engineering Program; 2007.
University of Zurich (2011, December 5). How muscle fatigue originates in the head. ScienceDaily. Retrieved
September 17, 2013
Figure 1A. -Young adults were stronger than the old adults as indicated by a greater peak torqueresults indicate that older adults are more fatigable than the younger adults when performing maximal muscular shortening and lengthening contractionswas due to changes of control of excitation-contraction coupling by Ca2+ and for the older adults only, impairment of neuromuscular propagation. Figure 1B. Each data denotes the time to failure for the one young man and one old man who were matched for strength. Older men could sustain the submaximal isometric contraction longer than young menthe rate at which fatigue developed during the submaximal isometric contraction was more gradual for the old men
There was no difference between genders with who could sustain the longest isometric contraction only when blood flow was occluded, even though force that men could exert was greater than that for the womenCommon explanation for this sex difference are the greater muscle mass activated by men and a lesser reliance on glycolytic metabolism by women.
Figure A and B. 3 sets of maximal shortening contractions and 3 sets of matched maximal isometric contractions with the knee extensor muscles. After the third trial there is a reduced MVC torque by 59 % After the third trial there is a reduced voluntary activation by 35.7% Initial values were 88.3% for the session in which shortening contractions were performedInitial values were 89.4% for the session in which isometric contractions were performed.