Abstract
PurposeA lack of fatigue-related muscle contractile property changes at time of perceived physical exhaustion and greater central than peripheral fatigue detected by twitch interpolation technique have recently been reported in cancer survivors with fatigue symptoms. Based on these observations, it was hypothesized that compared to healthy people, myoelectrical manifestation of fatigue in the performing muscles would be less significant in these individuals while sustaining a prolonged motor task to self-perceived exhaustion (SPE) since their central fatigue was more prominent. The purpose of this study was to test this hypothesis by examining electromyographic (EMG) signal changes during fatiguing muscle performance.MethodsTwelve individuals who had advanced solid cancer and cancer-related fatigue (CRF), and 12 age- and gender-matched healthy controls performed a sustained elbow flexion at 30% maximal voluntary contraction till SPE. Amplitude and mean power frequency (MPF) of EMG signals of the biceps brachii, brachioradialis, and triceps brachii muscles were evaluated when the individuals experienced minimal, moderate, and severe fatigue.ResultsCRF patients perceived physical “exhaustion” significantly sooner than the controls. The myoelectrical manifestation of muscular fatigue assessed by EMG amplitude and MPF was less significant in CRF than controls. The lower MPF even at minimal fatigue stage in CRF may indicate pathophysiologic condition of the muscle.ConclusionsCRF patients experience less myoelectrical manifestation of muscle fatigue than healthy individuals near the time of SPE. The data suggest that central nervous system fatigue plays a more important role in limiting endurance-type of motor performance in patients with CRF.
Highlights
Fatigue and physical impairments are prevalent in cancer survivors [1]
The degree of peripheral fatigue is often determined by electrical stimulation in which one or more supermaximalintensity electrical pulses are applied to a muscle or the nerve going into the muscle and measuring the evoked twich force response
During voluntary exercise the failure to maintain the required force depends on peripheral fatigue occurring distal to the point of stimulation and on central fatigue resulting from a failure to activate the muscle voluntarily [6]
Summary
Fatigue and physical impairments are prevalent in cancer survivors [1]. Cancer-related fatigue (CRF) is a major factor that limits physical abilities in these individuals. During voluntary exercise the failure to maintain the required force depends on peripheral fatigue occurring distal to the point of stimulation and on central fatigue resulting from a failure to activate the muscle voluntarily [6]. A lack of fatigue-related muscle contractile property changes at the time of perceived physical exhaustion has recently been reported in cancer survivors with fatigue symptoms [8]. CRF patients exhibited greater central than peripheral fatigue when performing a typical submaximal-level muscle contraction till self-perceived exhaustion (SPE) and task failure [9]. CRF patients felt exhausted and could no longer continue muscle activity, the muscle was still able to produce force by an external input (electrical stimulation), indicating that muscle fatigue was less at the time of SPE [9]. Evidence of less prominent myoelectrical manifestation of muscle fatigue at the time of SPE in CRF measured by standard myoelectrical fatigue parameters has not been demonstrated
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
