title: Changes in agonist neural drive, hypertrophy and pre-training strength all contribute to the individual strength gains after resistance training.
abstract: OBJECTIVE
  Whilst neural and morphological adaptations following resistance training (RT) have been investigated extensively at a group level, relatively little is known about the contribution of specific physiological mechanisms, or pre-training strength, to the individual changes in strength following training. This study investigated the contribution of multiple underpinning neural [agonist EMG (QEMGMVT), antagonist EMG (HEMGANTAG)] and morphological variables [total quadriceps volume (QUADSVOL), and muscle fascicle pennation angle (QUADSθp)], as well as pre-training strength, to the individual changes in strength after 12 weeks of knee extensor RT.
  
  
  METHODS
  Twenty-eight healthy young men completed 12 weeks of isometric knee extensor RT (3/week). Isometric maximum voluntary torque (MVT) was assessed pre- and post-RT, as were simultaneous neural drive to the agonist (QEMGMVT) and antagonist (HEMGANTAG). In addition QUADSVOLwas determined with MRI and QUADSθpwith B-mode ultrasound.
  
  
  RESULTS
  Percentage changes (∆) in MVT were correlated to ∆QEMGMVT(r = 0.576, P = 0.001), ∆QUADSVOL(r = 0.461, P = 0.014), and pre-training MVT (r = -0.429, P = 0.023), but not ∆HEMGANTAG(r = 0.298, P = 0.123) or ∆QUADSθp(r = -0.207, P = 0.291). Multiple regression analysis revealed 59.9% of the total variance in ∆MVT after RT to be explained by ∆QEMGMVT(30.6%), ∆QUADSVOL(18.7%), and pre-training MVT (10.6%).
  
  
  CONCLUSIONS
  Changes in agonist neural drive, quadriceps muscle volume and pre-training strength combined to explain the majority of the variance in strength changes after knee extensor RT (~60%) and adaptations in agonist neural drive were the most important single predictor during this short-term intervention.
authors.affiliation: Arthritis Research UK Centre for Sport, Exercise and Osteoarthritis, Loughborough University, Leicestershire, UK. t.g.balshaw@lboro.ac.uk.|School of Sport, Exercise, and Health Sciences, Loughborough University, Leicestershire, LE11 3TU, UK. t.g.balshaw@lboro.ac.uk.
authors.forename: Thomas G
authors.initials: TG
authors.lastname: Balshaw
authors.affiliation: Arthritis Research UK Centre for Sport, Exercise and Osteoarthritis, Loughborough University, Leicestershire, UK.|School of Sport, Exercise, and Health Sciences, Loughborough University, Leicestershire, LE11 3TU, UK.
authors.forename: Garry J
authors.initials: GJ
authors.lastname: Massey
authors.affiliation: School of Sport, Exercise, and Health Sciences, Loughborough University, Leicestershire, LE11 3TU, UK.|Faculty of Health and Wellbeing, Collegiate Campus, Sheffield Hallam University, Sheffield, UK.
authors.forename: Thomas M
authors.initials: TM
authors.lastname: Maden-Wilkinson
authors.affiliation: School of Sport, Exercise, and Health Sciences, Loughborough University, Leicestershire, LE11 3TU, UK.
authors.forename: Antonio J
authors.initials: AJ
authors.lastname: Morales-Artacho
authors.affiliation: School of Sport, Exercise, and Health Sciences, Loughborough University, Leicestershire, LE11 3TU, UK.
authors.forename: Alexandra
authors.initials: A
authors.lastname: McKeown
authors.affiliation: School of Sport, Exercise, and Health Sciences, Loughborough University, Leicestershire, LE11 3TU, UK.
authors.forename: Clare L
authors.initials: CL
authors.lastname: Appleby
authors.affiliation: Arthritis Research UK Centre for Sport, Exercise and Osteoarthritis, Loughborough University, Leicestershire, UK.|School of Sport, Exercise, and Health Sciences, Loughborough University, Leicestershire, LE11 3TU, UK.
authors.forename: Jonathan P
authors.initials: JP
authors.lastname: Folland
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D019054:Evoked Potentials, Motor; D006801:Humans; D007537:Isometric Contraction; D008297:Male; D053580:Muscle Strength; D052097:Quadriceps Muscle / Q000000981:diagnostic imaging / Q000294:innervation / Q000502:physiology*; D011897:Random Allocation; D055070:Resistance Training
keywords: Between-individual variability; Muscle architecture; Muscle volume; Neural drive; Strength training