title: Short rest interval lengths between sets optimally enhance body composition and performance with 8 weeks of strength resistance training in older men.
abstract: OBJECTIVE
  To determine if 8 weeks of periodized strength resistance training (RT) utilizing relatively short rest interval lengths (RI) in between sets (SS) would induce greater improvements in body composition and muscular performance, compared to the same RT program utilizing extended RI (SL).
  
  
  METHODS
  22 male volunteers (SS: n = 11, 65.6 ± 3.4 years; SL: n = 11, 70.3 ± 4.9 years) were assigned to one of two strength RT groups, following 4 weeks of periodized hypertrophic RT (PHRT): strength RT with 60-s RI (SS) or strength RT with 4-min RI (SL). Prior to randomization, all 22 study participants trained 3 days/week, for 4 weeks, targeting hypertrophy; from week 4 to week 12, SS and SL followed the same periodized strength RT program for 8 weeks, with RI the only difference in their RT prescription.
  
  
  RESULTS
  Following PHRT, all study participants experienced increases in lean body mass (LBM) (p < 0.01), upper and lower body strength (p < 0.001), and dynamic power (p < 0.001), as well as decreases in percentage body fat (p < 0.05). Across the 8-week strength RT phase, SS experienced significantly greater increases in LBM (p = 0.001), flat machine bench press 1-RM (p < 0.001), bilateral leg press 1-RM (p < 0.001), narrow/neutral grip lat pulldown (p < 0.01), and Margaria stair-climbing power (p < 0.001), compared to SL.
  
  
  CONCLUSIONS
  This study suggests 8 weeks of periodized high-intensity strength RT with shortened RI induces significantly greater enhancements in body composition, muscular performance, and functional performance, compared to the same RT prescription with extended RI, in older men. Applied professionals may optimize certain RT-induced adaptations, by incorporating shortened RI.
authors.affiliation: Division of Biokinesiology and Physical Therapy, Clinical Exercise Research Center, University of Southern California, 1540 E. Alcazar St., CHP-149, Los Angeles, CA, 90089, USA.
authors.forename: Matthew G
authors.initials: MG
authors.lastname: Villanueva
authors.forename: Christianne Joy
authors.initials: CJ
authors.lastname: Lane
authors.forename: E Todd
authors.initials: ET
authors.lastname: Schroeder
mesh_terms: D000368:Aged; D054874:Athletic Performance; D001823:Body Composition; D006801:Humans; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000254:growth & development / Q000502:physiology; D055070:Resistance Training / Q000379:methods*; D055948:Sarcopenia / Q000628:therapy*