Abstract
BACKGROUND AND AIMS: This study investigated whether high-velocity high-power training (POW) improved lower extremity muscle power and quality in functionally-limited elders greater than traditional slow-velocity progressive resistance training (STR). METHODS: Fifty-seven community-dwelling older adults aged 74.2+/-7 (range 65-94 yrs), Short Physical Performance Battery score 7.7+/-1.4, were randomized to either POW (n=23) (12 females), STR (n=22) (13 females) or a control group of lower extremity stretching (CON) (n=12) (6 females). Training was performed three times per week for 12 weeks and subjects completed three sets of double leg press and knee extension exercises at 70% of the one repetition maximum (1RM). Outcome measures included 1RM strength and peak power (PP). Total leg lean mass was determined using dual-energy X-ray absorptiometry to estimate specific strength and specific PP. RESULTS: During training, power output was consistently higher in POW compared to STR for knee extension (approximately 2.3-fold) and leg press (approximately 2.8-fold) exercises (p<0.01). Despite this, PP and specific PP of the knee extensors increased similarly from baseline in POW and STR compared to CON (p<0.01), and no significant time-group interaction occurred for PP of the leg extensors. However, gains in leg press specific PP were significantly greater in POW compared to both STR and CON (p<0.05). Total leg lean mass did not change within any group. CONCLUSIONS: A short-term intervention of high-velocity power training and traditional slow-velocity progressive resistance training yielded similar increases of lower extremity power in the mobility-impaired elderly. Neuromuscular adaptations to power training, rather than skeletal muscle hypertrophy, may have facilitated the improvements in muscle quality. Additional studies are warranted to test the efficacy of power training in older individuals with compromised physical functioning.