title: Short-term unilateral resistance training affects the agonist-antagonist but not the force-agonist activation relationship.
abstract: In this study we investigated the contribution of neural adaptations to strength changes after 4 weeks of unilateral isometric resistance training. Maximal and submaximal isometric knee extension contractions were assessed before and after training. Surface electromyography (EMG) data were collected from the agonist and antagonist muscles and normalized to evoked maximal M-wave and maximal knee flexor EMG, respectively. The interpolated twitch technique (ITT) was also used to determine activation at maximum voluntary force (MVF). MVF increased in the trained (+20%) and untrained (+8%) legs. Agonist EMG at MVF increased in the trained leg (+26%), although activation determined via the ITT was unchanged. In both legs the position of the force-agonist EMG relationship was unchanged, but antagonist coactivation was lower for all levels of agonist activation. Strength gains in the trained leg were due to enhanced agonist activation, whereas decreased coactivation may have affected strength changes in both legs.
authors.affiliation: School of Sport, Exercise and Health Sciences, Loughborough University, Leicestershire, Ashby Road, Loughborough, Leicestershire LE11 3TU, UK. Tillin@roehampton.ac.uk
authors.forename: Neale A
authors.initials: NA
authors.lastname: Tillin
authors.forename: Matthew T G
authors.initials: MT
authors.lastname: Pain
authors.forename: Jonathan P
authors.initials: JP
authors.lastname: Folland
mesh_terms: D004558:Electric Stimulation / Q000379:methods; D004576:Electromyography / Q000379:methods; D006801:Humans; D007537:Isometric Contraction / Q000502:physiology*; D008297:Male; D053580:Muscle Strength / Q000502:physiology*; D055070:Resistance Training / Q000379:methods*; D013997:Time Factors; D055815:Young Adult