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Force decline during fatigue is due to both a decrease in the force per individual cross‐bridge and the number of cross‐bridges
Author(s) -
Nocella Marta,
Colombini Barbara,
Benelli Giulia,
Cecchi Giovanni,
Bagni M. Angela,
Bruton Joseph
Publication year - 2011
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1113/jphysiol.2011.209874
Subject(s) - bridge (graph theory) , structural engineering , forensic engineering , materials science , medicine , engineering
Non‐technical summary Prolonged muscle activity leads to a reduction of mechanical power and force output which is commonly indicated as muscular fatigue. The development of fatigue during repetitive stimulation of a skeletal muscle consists of an initial phase during which force decreases by 10–15%. This is followed by a second phase where force remains almost constant and finally a phase during which force drops precipitously to low levels. We show here that the initial fall in force is due to a reduction of the force generated by the individual molecular force generator, the cross‐bridge, whereas in subsequent phases the force decrease is caused by a reduction in the number of molecular force generators. These results increase our understanding of muscular fatigue mechanisms.