title: Daily L-leucine supplementation in novice trainees during a 12-week weight training program.
abstract: OBJECTIVE
  To investigate the effects of daily oral L-leucine ingestion on strength, bone mineral-free lean tissue mass (LTM) and fat mass (FM) of free living humans during a 12-wk resistance-training program.
  
  
  METHODS
  Twenty-six initially untrained men (n = 13 per group) ingested either 4 g/d of L-leucine (leucine group: age 28.5 ± 8.2 y, body mass index 24.9 ± 4.2 kg/m2) or a corresponding amount of lactose (placebo group: age 28.2 ± 7.3 y, body mass index 24.9 ± 4.2 kg/m2). All participants trained under supervision twice per week following a prescribed resistance training program using eight standard exercise machines. Testing took place at baseline and at the end of the supplementation period. Strength on each exercise was assessed by five repetition maximum (5-RM), and body composition was assessed by dual energy X-ray absorptiometry (DXA).
  
  
  RESULTS
  The leucine group demonstrated significantly higher gains in total 5-RM strength (sum of 5-RM in eight exercises) and 5-RM strength in five out of the eight exercises (P < .05). The percentage total 5-RM strength gains were 40.8% (± 7.8) and 31.0% (± 4.6) for the leucine and placebo groups respectively. Significant differences did not exist between groups in either total percentage LTM gains or total percentage FM losses (LTM: 2.9% ± 2.5 vs 2.0% ± 2.1, FM: 1.6% ± 15.6 vs 1.1% ± 7.6).
  
  
  CONCLUSIONS
  These results suggest that 4 g/d of L-leucine supplementation may be used as a nutritional supplement to enhance strength performance during a 12-week resistance training program of initially untrained male participants.
authors.affiliation: Carnegie Faculty of Sport and Education, Leeds Metropolitan University, Leeds, UK.
authors.forename: Theocharis
authors.initials: T
authors.lastname: Ispoglou
authors.forename: Roderick F G J
authors.initials: RF
authors.lastname: King
authors.forename: Remco C J
authors.initials: RC
authors.lastname: Polman
authors.forename: Cathy
authors.initials: C
authors.lastname: Zanker
mesh_terms: D015502:Absorptiometry, Photon; D000284:Administration, Oral; D000328:Adult; D015415:Biomarkers / Q000097:blood; D001823:Body Composition / Q000187:drug effects; D015992:Body Mass Index; D019587:Dietary Supplements; D004311:Double-Blind Method; D004334:Drug Administration Schedule; D002149:Energy Intake; D006801:Humans; D007930:Leucine / Q000008:administration & dosage*; D008297:Male; D053580:Muscle Strength / Q000187:drug effects*; D010465:Perception; D055070:Resistance Training; D013997:Time Factors; D014891:Weight Lifting; D055815:Young Adult
chemical_list: D015415:Biomarkers; D007930:Leucine