title: Strength training at high versus low external resistance in older adults: effects on muscle volume, muscle strength, and force-velocity characteristics.
abstract: Muscle adaptations can be induced by high-resistance exercise. Despite being potentially more suitable for older adults, low-resistance exercise protocols have been less investigated. We compared the effects of high- and low-resistance training on muscle volume, muscle strength, and force-velocity characteristics. Fifty-six older adults were randomly assigned to 12 weeks of leg press and leg extension training at either HIGH (2×10-15 repetitions at 80% of one repetition maximum (1RM)), LOW (1×80-100 repetitions at 20% of 1RM), or LOW+ (1×60 repetitions at 20% of 1RM, followed by 1×10-20 repetitions at 40% of 1RM). All protocols ended with muscle failure. Leg press and leg extension of 1RM were measured at baseline and post intervention and before the first training session in weeks 5 and 9. At baseline and post intervention, muscle volume (MV) was measured by CT-scan. A Biodex dynamometer evaluated knee extensor static peak torque in different knee angles (PT(stat90°), PT(stat120°), PT(stat150°)), dynamic peak torque at different speeds (PT(dyn60°s)(-1), PT(dyn180°s)(-1), PT(dyn240°s)(-1)), and speed of movement at 20% (S20), 40% (S40), and 60% (S60) of PTstat90°. HIGH and LOW+ resulted in greater improvements in 1RM strength than LOW (p<0.05). These differences were already apparent after week 5. Similar gains were found between groups in MV, PT(stat), PT(dyn60°s)(-1), and PT(dyn180°s)(-1). No changes were reported in speed of movement. HIGH tended to improve PT(dyn240°s)(-1) more than LOW or LOW+ (p=0.064). In conclusion, high- and low-resistance exercises ending with muscle failure may be similarly effective for hypertrophy. High-resistance training led to a higher increase in 1RM strength than low-resistance training (20% of 1RM), but this difference disappeared when using a mixed low-resistance protocol in which the resistance was intensified within a single exercise set (40% of 1RM). Our findings support the need for more research on low-resistance programs in older age, in particular long-term training studies and studies focusing on residual effects after training cessation.
authors.affiliation: Physical Activity, Sports and Health Research Group, Department of Kinesiology, Faculty of Kinesiology and Rehabilitation Sciences, Katholieke Universiteit Leuven, Tervuursevest 101, 3001 Leuven, Belgium. Electronic address: evelien.vanroie@faber.kuleuven.be.
authors.forename: Evelien
authors.initials: E
authors.lastname: Van Roie
authors.forename: Christophe
authors.initials: C
authors.lastname: Delecluse
authors.forename: Walter
authors.initials: W
authors.lastname: Coudyzer
authors.forename: Steven
authors.initials: S
authors.lastname: Boonen
authors.forename: Ivan
authors.initials: I
authors.lastname: Bautmans
mesh_terms: D000368:Aged; D000375:Aging / Q000473:pathology / Q000502:physiology*; D001696:Biomechanical Phenomena; D005260:Female; D006801:Humans; D006984:Hypertrophy; D008297:Male; D008875:Middle Aged; D018763:Muscle Fatigue / Q000502:physiology; D053580:Muscle Strength / Q000502:physiology*; D018482:Muscle, Skeletal / Q000473:pathology / Q000502:physiology; D055070:Resistance Training / Q000379:methods*; D019415:Torque
keywords: Elderly; Muscle fatigue; Muscle hypertrophy; Resistance training; Training load