title: Blood flow-restricted strength training displays high functional and biological efficacy in women: a within-subject comparison with high-load strength training.
abstract: Limited data exist on the efficacy of low-load blood flow-restricted strength training (BFR), as compared directly to heavy-load strength training (HST). Here, we show that 12 wk of twice-a-week unilateral BFR [30% of one repetition maximum (1RM) to exhaustion] and HST (6-10RM) of knee extensors provide similar increases in 1RM knee extension and cross-sectional area of distal parts of musculus quadriceps femoris in nine untrained women (age 22 ± 1 yr). The two protocols resulted in similar acute increases in serum levels of human growth hormone. On the cellular level, 12 wk of BFR and HST resulted in similar shifts in muscle fiber composition in musculus vastus lateralis, evident as increased MyHC2A proportions and decreased MyHC2X proportions. They also resulted in similar changes of the expression of 29 genes involved in skeletal muscle function, measured both in a rested state following 12 wk of training and subsequent to singular training sessions. Training had no effect on myonuclei proportions. Of particular interest, 1) gross adaptations to BFR and HST were greater in individuals with higher proportions of type 2 fibers, 2) both BFR and HST resulted in approximately four-fold increases in the expression of the novel exercise-responsive gene Syndecan-4, and 3) BFR provided lesser hypertrophy than HST in the proximal half of musculus quadriceps femoris and also in CSApeak, potentially being a consequence of pressure from the tourniquet utilized to achieve blood flow restriction. In conclusion, BFR and HST of knee extensors resulted in similar adaptations in functional, physiological, and cell biological parameters in untrained women.
authors.affiliation: Lillehammer University College, Lillehammer, Norway; stian.ellefsen@hil.no.
authors.forename: Stian
authors.initials: S
authors.lastname: Ellefsen
authors.affiliation: Lillehammer University College, Lillehammer, Norway;
authors.forename: Daniel
authors.initials: D
authors.lastname: Hammarström
authors.affiliation: Innlandet Hospital Trust, Lillehammer, Norway;
authors.forename: Tor A
authors.initials: TA
authors.lastname: Strand
authors.affiliation: Lillehammer University College, Lillehammer, Norway;
authors.forename: Erika
authors.initials: E
authors.lastname: Zacharoff
authors.affiliation: Innlandet Hospital Trust, Lillehammer, Norway;
authors.forename: Jon E
authors.initials: JE
authors.lastname: Whist
authors.affiliation: Innlandet Hospital Trust, Lillehammer, Norway;
authors.forename: Irene
authors.initials: I
authors.lastname: Rauk
authors.affiliation: Lillehammer University College, Lillehammer, Norway;
authors.forename: Håvard
authors.initials: H
authors.lastname: Nygaard
authors.affiliation: Lillehammer University College, Lillehammer, Norway;
authors.forename: Geir
authors.initials: G
authors.lastname: Vegge
authors.affiliation: Innlandet Hospital Trust, Lillehammer, Norway;
authors.forename: Marita
authors.initials: M
authors.lastname: Hanestadhaugen
authors.affiliation: Lundberg Laboratory for Orthopaedic Research, Department of Orthopedics, The Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden; and Center for Health and Performance, Department of Food and Nutrition and Sport Science, University of Gothenburg, Gothenburg, Sweden.
authors.forename: Mathias
authors.initials: M
authors.lastname: Wernbom
authors.affiliation: Norwegian School of Sport Science, Oslo, Norway;
authors.forename: Kristoffer T
authors.initials: KT
authors.lastname: Cumming
authors.affiliation: Innlandet Hospital Trust, Lillehammer, Norway;
authors.forename: Roar
authors.initials: R
authors.lastname: Rønning
authors.affiliation: Norwegian School of Sport Science, Oslo, Norway;
authors.forename: Truls
authors.initials: T
authors.lastname: Raastad
authors.affiliation: Lillehammer University College, Lillehammer, Norway;
authors.forename: Bent R
authors.initials: BR
authors.lastname: Rønnestad
mesh_terms: D019412:Anatomy, Cross-Sectional; D001706:Biopsy; D002452:Cell Count; D005260:Female; D015870:Gene Expression; D006728:Hormones / Q000097:blood; D006801:Humans; D007150:Immunohistochemistry; D007866:Leg / Q000502:physiology; D008279:Magnetic Resonance Imaging; D018485:Muscle Fibers, Skeletal / Q000502:physiology; D053580:Muscle Strength / Q000235:genetics* / Q000502:physiology*; D018482:Muscle, Skeletal / Q000033:anatomy & histology / Q000166:cytology / Q000502:physiology; D012333:RNA, Messenger / Q000032:analysis / Q000096:biosynthesis; D012039:Regional Blood Flow / Q000502:physiology*; D055070:Resistance Training / Q000379:methods*; D014111:Tourniquets; D055815:Young Adult
chemical_list: D006728:Hormones; D012333:RNA, Messenger
keywords: gene expression; heavy-load strength training; low-load blood flow-restricted training; muscle fiber; muscle strength and mass