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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

Time course of FD and CV in the VL (red) and VM (blue) muscles during 20% and 60% MVC.Data are presented as median (circles), interquartile range (rectangles), and range (vertical lines) normalized with respect to their initial values. The time axis is divided in ten epochs. For the 20%MVC the epoch length is 3 s, being 30 s the duration of the contraction, while for the endurance 60%MVC contraction the epoch length is 10% of the total endurance time.
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pone.0123921.g002: Time course of FD and CV in the VL (red) and VM (blue) muscles during 20% and 60% MVC.Data are presented as median (circles), interquartile range (rectangles), and range (vertical lines) normalized with respect to their initial values. The time axis is divided in ten epochs. For the 20%MVC the epoch length is 3 s, being 30 s the duration of the contraction, while for the endurance 60%MVC contraction the epoch length is 10% of the total endurance time.

Mentions: The average time course of FD and CV during 20% and 60% MVC is shown in Fig 2. Significant negative slopes for FD and CV were observed during the sustained 60% MVC compared with the lower-intensity contraction, in particular in the VM muscle.


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)

Time course of FD and CV in the VL (red) and VM (blue) muscles during 20% and 60% MVC.Data are presented as median (circles), interquartile range (rectangles), and range (vertical lines) normalized with respect to their initial values. The time axis is divided in ten epochs. For the 20%MVC the epoch length is 3 s, being 30 s the duration of the contraction, while for the endurance 60%MVC contraction the epoch length is 10% of the total endurance time.
© Copyright Policy
Related In: Results  -  Collection

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

pone.0123921.g002: Time course of FD and CV in the VL (red) and VM (blue) muscles during 20% and 60% MVC.Data are presented as median (circles), interquartile range (rectangles), and range (vertical lines) normalized with respect to their initial values. The time axis is divided in ten epochs. For the 20%MVC the epoch length is 3 s, being 30 s the duration of the contraction, while for the endurance 60%MVC contraction the epoch length is 10% of the total endurance time.
Mentions: The average time course of FD and CV during 20% and 60% MVC is shown in Fig 2. Significant negative slopes for FD and CV were observed during the sustained 60% MVC compared with the lower-intensity contraction, in particular in the VM muscle.

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