title: Evidence of muscular adaptations within four weeks of barbell training in women.
abstract: We investigated the time course of neuromuscular and hypertrophic adaptations associated with only four weeks of barbell squat and deadlift training. Forty-seven previously untrained women (mean±SD, age=21±3years) were randomly assigned to low volume training (n=15), moderate volume training (n=16), and control (n=16) groups. The low and moderate volume training groups performed two and four sets, respectively, of five repetitions per exercise, twice a week. Testing was performed weekly, and included dual X-ray absorptiometry and vastus lateralis and rectus femoris B-mode ultrasonography. Bipolar surface electromyographic (EMG) signals were detected from the vastus lateralis and biceps femoris during isometric maximal voluntary contractions of the leg extensors. Significant increases in lean mass for the combined gynoid and leg regions for the low (+0.68kg) and moderate volume (+0.47kg) groups were demonstrated within three weeks. Small-to-moderate effect sizes were shown for leg lean mass, vastus lateralis thickness and pennation angle, and peak torque, but EMG amplitude was unaffected. These findings demonstrated rapid muscular adaptations in response to only eight sessions of back squat and deadlift training in women despite the absence of changes in agonist-antagonist EMG amplitude.
authors.affiliation: Human Performance Laboratory, Texas Tech University, Lubbock, TX, USA. Electronic address: matt.stock@ttu.edu.
authors.forename: Matt S
authors.initials: MS
authors.lastname: Stock
authors.affiliation: Human Performance Laboratory, Texas Tech University, Lubbock, TX, USA.
authors.forename: Kendra D
authors.initials: KD
authors.lastname: Olinghouse
authors.affiliation: Center for Rehabilitation Research, Texas Tech University Health Science Center, Lubbock, TX, USA.
authors.forename: Alexander S
authors.initials: AS
authors.lastname: Drusch
authors.affiliation: Human Performance Laboratory, Texas Tech University, Lubbock, TX, USA.
authors.forename: Jacob A
authors.initials: JA
authors.lastname: Mota
authors.affiliation: Human Performance Laboratory, Texas Tech University, Lubbock, TX, USA.
authors.forename: Jennah M
authors.initials: JM
authors.lastname: Hernandez
authors.affiliation: Human Performance Laboratory, Texas Tech University, Lubbock, TX, USA.
authors.forename: Chibuzo C
authors.initials: CC
authors.lastname: Akalonu
authors.affiliation: Neuromuscular Research Laboratory, Utah State University, Logan, UT, USA.
authors.forename: Brennan J
authors.initials: BJ
authors.lastname: Thompson
mesh_terms: D000222:Adaptation, Physiological / Q000502:physiology*; D000293:Adolescent; D000328:Adult; D015992:Body Mass Index; D004576:Electromyography; D005260:Female; D006801:Humans; D007537:Isometric Contraction / Q000502:physiology*; D053580:Muscle Strength / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology*; D052097:Quadriceps Muscle / Q000502:physiology; D012737:Sex Factors; D019415:Torque; D014891:Weight Lifting / Q000502:physiology*; D055815:Young Adult
keywords: Motor unit; Resistance training; Vastus lateralis