Time course of changes in torque and neuromuscular parameters during a sustained isometric forearm flexion task to fatigue anchored to a constant rating of perceived exertion.
J Musculoskelet Neuronal Interact
; 22(4): 455-464, 2022 12 01.
Article
in En
| MEDLINE
| ID: mdl-36458383
ABSTRACT
OBJECTIVE:
This study examined the time course of changes in torque and electromyographic (EMG) and mechanomyographic (MMG) responses during a sustained isometric task anchored to a constant perception of exertion (RPE).METHODS:
Twelve college-aged men performed an isometric forearm flexion task to failure anchored to RPE=7 (OMNI-RES scale). The amplitude (AMP) and frequency (MPF) of the EMG and MMG signals from the biceps brachii were recorded. Repeated measures ANOVAs were used to examine differences for the normalized (%MVIC) torque and neuromuscular parameters.RESULTS:
The time to task failure (TTF) was 678.0±468.1s. Torque decreased significantly (p<0.001, ηp2=0.774) across time and all subjects reduced torque to zero. Post-hoc comparisons indicated that the torque values from 20-100% TTF were less than the value at 10% TTF. There were no significant (p>0.05) changes from 10-100% TTF for the EMG and MMG parameters.CONCLUSION:
We hypothesize that RPE was maintained by various mechanisms throughout the task group III/IV afferent neurons, adequate blood flow, and a combination of reduced contractile efficiency, collective afferent feedback (group III/IV afferents) from muscles involved with forearm flexion, and motivation that resulted in an initial decrease, plateau, and final decline in torque to zero, respectively.Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Physical Exertion
/
Forearm
Limits:
Adult
/
Humans
/
Male
Language:
En
Journal:
J Musculoskelet Neuronal Interact
Journal subject:
FISIOLOGIA
/
NEUROLOGIA
/
ORTOPEDIA
Year:
2022
Document type:
Article
Affiliation country: