Explosive-type Strength Training in the Elderly

Abstract

The age-related decline in muscle power and explosive force capacity (i.e. contractile rate of force development RFD) is as stronger predictor for incidence of falling, motor impairment, self-reported functional status and balance capability in community-dwelling old adults than maximal muscle strength per se. It was therefore recently suggested to develop strength training programmes aimed at maximising maximal muscle power and RFD by implementing explosive concentric movements with training loads of 40–60% of 1RM. However, older individuals often perform weight-bearing motor tasks close to their maximum capability (i.e. 1RM) and above especially during unexpected tasks such as reversing an impending fall. PURPOSE: To investigate the effect of 12-week, twice a week, heavy-resistance strength training (75–80 % of 1RM) with fast-to-explosive execution of the movements on maximal voluntary contraction (MVC), explosive force characteristics (RFD and impulse), muscle power and functional performances in two age-groups of community-dwelling elderly women (TG60, TG80, age-groups 60 and 80, respectively). METHODS: Elderly women from two age-groups, 60 (62.7 2.2 years, n=40) and 80 (81.8 2.7 years, n=25) were randomized (matched) into two training and two control groups (TG60, n=20; TG80, n=12) (CG 60, n=20; CG80, n=13). MVC, RFD and impulse were obtained during a maximal isometric unilateral leg press manuevre. Mechanical performance was assessed as jump height, (JH) and peak power (Ppeak) in a standardized countermovement jump (CMJ) and as mean power (Prigmean). in the Nottingham single-legged power rig. Functional motor performances were i) five-repeated chair rise, ii) 10-m walking test at self selected and maximal speed, and iii) Physical Performance Test (PPT). RESULTS: RFD, impulse, MVC, P peak', JH and Prigmean increased with training in both age-groups. The gains in RFD (50.5%), impulse (41.9%) and MVC (28.1%) for TG 80 were of such a magnitude that the difference observed pre intervention with the age-group 60 was abolished after training. Chair-rise and PPT improved in TG80 and only chair rise in TG60, whereas no improvements occurred in self-selected and maximal 10-meter gait speed. CONCLUSIONS: The present findings indicate that heavy-resistance strength training performed with explosive movement characteristics is highly effective in inducing adaptive neuromuscular changes in selected physiological variables and functional performances commonly associated with risk of falls and disability in aged individuals. This training modality seems to be safe and suitable for healthy women even in the 8th decade of life.