title: Time Course of Resistance Training-Induced Muscle Hypertrophy in the Elderly.
abstract: Extended periods of resistance training (RT) induce muscle hypertrophy. Nevertheless, to date, no study has investigated the time window necessary to observe significant changes in muscle cross-sectional area (CSA) in older adults. Therefore, this study investigated the time course of muscle hypertrophy after 10 weeks (20 sessions) of RT in the elderly. Fourteen healthy older subjects were randomly allocated in either the RT (n: 6) or control group (n: 8). The RT was composed of 4 sets × 10 repetitions (70-80% 1 repetition maximum [1RM]) in a leg press machine. The time course of vastus lateralis muscle hypertrophy (CSA) was assessed on a weekly basis by mode-B ultrasonography. Leg press muscle strength was assessed by dynamic 1RM test. Our results demonstrated that the RT group increased leg press 1RM by 42% (p ≤ 0.05) after 10 weeks of training. Significant increases in vastus lateralis muscle CSA were observed only after 18 sessions of training (9 weeks; p ≤ 0.05; 7.1%). In conclusion, our training protocol promoted muscle mass accrual in older subjects, and this was only observable after 18 sessions of RT (9 weeks).
authors.affiliation: 1Faculty of Physical Education, University of Campinas, Campinas, Sao Paulo, Brazil; 2School of Physical Education and Sport, University of Sao Paulo, Sao Paulo, Brazil; 3College of Physical Education, University of Brasilia, Brasilia, Brazil; and 4Department of Physical Education, Center of Biological and Health Sciences, Federal University of Sao Carlos, Sao Carlos, Sao Paulo, Brazil.
authors.forename: Manoel E
authors.initials: ME
authors.lastname: Lixandrão
authors.forename: Felipe
authors.initials: F
authors.lastname: Damas
authors.forename: Mara P T
authors.initials: MP
authors.lastname: Chacon-Mikahil
authors.forename: Claudia R
authors.initials: CR
authors.lastname: Cavaglieri
authors.forename: Carlos
authors.initials: C
authors.lastname: Ugrinowitsch
authors.forename: Martim
authors.initials: M
authors.lastname: Bottaro
authors.forename: Felipe C
authors.initials: FC
authors.lastname: Vechin
authors.forename: Miguel S
authors.initials: MS
authors.lastname: Conceição
authors.forename: Ricardo
authors.initials: R
authors.lastname: Berton
authors.forename: Cleiton A
authors.initials: CA
authors.lastname: Libardi
mesh_terms: D000368:Aged; D005080:Exercise Test; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D053580:Muscle Strength; D009929:Organ Size; D052097:Quadriceps Muscle / Q000000981:diagnostic imaging* / Q000254:growth & development* / Q000502:physiology; D055070:Resistance Training; D013997:Time Factors; D014463:Ultrasonography