title: Effects of a ten-second maximum voluntary contraction on regulatory myosin light-chain phosphorylation and dynamic performance measures.
abstract: The purpose of this investigation was to evaluate the role of an elevated regulatory myosin light-chain (RLC) phosphorylation on subsequent postactivation potentiation induced by a 10-second maximum voluntary contraction (MVC). With the use of a repeated measures design, data were collected from 11 recreationally active men who performed an explosive knee extension exercise with a load of 70% of their 1 repetition maximum. Muscle biopsies of their vastus lateralis were taken pre- and post-MVC. Seven subjects had elevated RLC phosphorylation (positive responders) and 4 had a decrease in RLC phosphorylation (negative responders). Percent change of force, velocity, and power measures did not differ between the 2 groups. Our results suggest that recreationally active men will not benefit from the effects of postactivation potentiation during performance with a 7-minute recovery period. Furthermore, we suggest that training status, strength, and skill level might be key determining factors for the positive benefits of postactivation potentiation during performance.
authors.affiliation: Department of Neurobiology and Anatomy, Wake Forest University, Winston-Salem, North Carolina 27157, USA. chadsmit@wfubmc.edu
authors.forename: J Chadwick
authors.initials: JC
authors.lastname: Smith
authors.forename: Andrew C
authors.initials: AC
authors.lastname: Fry
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D006801:Humans; D007717:Knee; D008297:Male; D009119:Muscle Contraction / Q000502:physiology*; D018482:Muscle, Skeletal / Q000378:metabolism*; D018994:Myosin Light Chains / Q000378:metabolism*; D010766:Phosphorylation
chemical_list: D018994:Myosin Light Chains