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Evaluation of central and peripheral fatigue in the quadriceps using fractal dimension and conduction velocity in young females.

Beretta-Piccoli M, D'Antona G, Barbero M, Fisher B, Dieli-Conwright CM, Clijsen R, Cescon C - PLoS ONE (2015)

Bottom Line: To this aim, we analyzed FD and CV slopes during sustained fatiguing contractions of the quadriceps femoris in healthy humans.A total of 29 recreationally active women (mean age±standard deviation: 24±4 years) and two female elite athletes (one power athlete, age 24 and one endurance athlete, age 30 years) performed two knee extensions: (1) at 20% maximal voluntary contraction (MVC) for 30 s, and (2) at 60% MVC held until exhaustion.A positive correlation between FD and CV (R=0.51, p<0.01) was found during the sustained 60% MVC, probably as a result of simultaneous motor unit synchronization and a decrease in muscle fiber CV during the fatiguing task.

View Article: PubMed Central - PubMed

Affiliation: Rehabilitation Research Laboratory, Department of Business Economics, Health and Social Care, University of Applied Sciences and Arts of Southern Switzerland, SUPSI, Manno, Switzerland.

ABSTRACT

Purpose: Over the past decade, linear and non-linear surface electromyography descriptors for central and peripheral components of fatigue have been developed. In the current study, we tested fractal dimension (FD) and conduction velocity (CV) as myoelectric descriptors of central and peripheral fatigue, respectively. To this aim, we analyzed FD and CV slopes during sustained fatiguing contractions of the quadriceps femoris in healthy humans.

Methods: A total of 29 recreationally active women (mean age±standard deviation: 24±4 years) and two female elite athletes (one power athlete, age 24 and one endurance athlete, age 30 years) performed two knee extensions: (1) at 20% maximal voluntary contraction (MVC) for 30 s, and (2) at 60% MVC held until exhaustion. Surface EMG signals were detected from the vastus lateralis and vastus medialis using bidimensional arrays.

Results: Central and peripheral fatigue were described as decreases in FD and CV, respectively. A positive correlation between FD and CV (R=0.51, p<0.01) was found during the sustained 60% MVC, probably as a result of simultaneous motor unit synchronization and a decrease in muscle fiber CV during the fatiguing task.

Conclusions: Central and peripheral fatigue can be described as changes in FD and CV, at least in young, healthy women. The significant correlation between FD and CV observed at 60% MVC suggests that a mutual interaction between central and peripheral fatigue can arise during submaximal isometric contractions.

No MeSH data available.


Related in: MedlinePlus

Scatter plot of the normalized slopes of (A) FD versus CV and (B) FD versus VAD during 60% MVC.Data from the power and endurance athletes are superimposed in different colors. The R and p values of the Pearson’s correlation coefficient are indicated. Dashed red lines indicate linear regression performed on the data from healthy subjects.
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pone.0123921.g003: Scatter plot of the normalized slopes of (A) FD versus CV and (B) FD versus VAD during 60% MVC.Data from the power and endurance athletes are superimposed in different colors. The R and p values of the Pearson’s correlation coefficient are indicated. Dashed red lines indicate linear regression performed on the data from healthy subjects.

Mentions: A significant positive correlation was observed between FD and CV (R = 0.52, p<0.01; Fig 3A) and between VAD and FD (R = 0.49, p<0.01; Fig 3B) during 60% MVC.


Evaluation of central and peripheral fatigue in the quadriceps using fractal dimension and conduction velocity in young females.

Beretta-Piccoli M, D'Antona G, Barbero M, Fisher B, Dieli-Conwright CM, Clijsen R, Cescon C - PLoS ONE (2015)

Scatter plot of the normalized slopes of (A) FD versus CV and (B) FD versus VAD during 60% MVC.Data from the power and endurance athletes are superimposed in different colors. The R and p values of the Pearson’s correlation coefficient are indicated. Dashed red lines indicate linear regression performed on the data from healthy subjects.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4400165&req=5

pone.0123921.g003: Scatter plot of the normalized slopes of (A) FD versus CV and (B) FD versus VAD during 60% MVC.Data from the power and endurance athletes are superimposed in different colors. The R and p values of the Pearson’s correlation coefficient are indicated. Dashed red lines indicate linear regression performed on the data from healthy subjects.
Mentions: A significant positive correlation was observed between FD and CV (R = 0.52, p<0.01; Fig 3A) and between VAD and FD (R = 0.49, p<0.01; Fig 3B) during 60% MVC.

Bottom Line: To this aim, we analyzed FD and CV slopes during sustained fatiguing contractions of the quadriceps femoris in healthy humans.A total of 29 recreationally active women (mean age±standard deviation: 24±4 years) and two female elite athletes (one power athlete, age 24 and one endurance athlete, age 30 years) performed two knee extensions: (1) at 20% maximal voluntary contraction (MVC) for 30 s, and (2) at 60% MVC held until exhaustion.A positive correlation between FD and CV (R=0.51, p<0.01) was found during the sustained 60% MVC, probably as a result of simultaneous motor unit synchronization and a decrease in muscle fiber CV during the fatiguing task.

View Article: PubMed Central - PubMed

Affiliation: Rehabilitation Research Laboratory, Department of Business Economics, Health and Social Care, University of Applied Sciences and Arts of Southern Switzerland, SUPSI, Manno, Switzerland.

ABSTRACT

Purpose: Over the past decade, linear and non-linear surface electromyography descriptors for central and peripheral components of fatigue have been developed. In the current study, we tested fractal dimension (FD) and conduction velocity (CV) as myoelectric descriptors of central and peripheral fatigue, respectively. To this aim, we analyzed FD and CV slopes during sustained fatiguing contractions of the quadriceps femoris in healthy humans.

Methods: A total of 29 recreationally active women (mean age±standard deviation: 24±4 years) and two female elite athletes (one power athlete, age 24 and one endurance athlete, age 30 years) performed two knee extensions: (1) at 20% maximal voluntary contraction (MVC) for 30 s, and (2) at 60% MVC held until exhaustion. Surface EMG signals were detected from the vastus lateralis and vastus medialis using bidimensional arrays.

Results: Central and peripheral fatigue were described as decreases in FD and CV, respectively. A positive correlation between FD and CV (R=0.51, p<0.01) was found during the sustained 60% MVC, probably as a result of simultaneous motor unit synchronization and a decrease in muscle fiber CV during the fatiguing task.

Conclusions: Central and peripheral fatigue can be described as changes in FD and CV, at least in young, healthy women. The significant correlation between FD and CV observed at 60% MVC suggests that a mutual interaction between central and peripheral fatigue can arise during submaximal isometric contractions.

No MeSH data available.


Related in: MedlinePlus