Evidence for practice.

Inactivity coupled with muscle wasting and weakness often puts elderly persons at high risk for serious life-threatening falls, the most common cause of injury-related death in persons over 75 years of age. Paul LaStayo, PT, PhD, CHT, a Foundation PODS II and NIFTI recipient, and colleagues reported important findings from their research project that was funded by the National Institute on Aging and supported by the Foundation for Physical Therapy and Arizona Proposition 301 Biotechnology Funds. The purpose of this project was to determine if a chronic eccentric exercise training (ie, negative work) intervention could limit or even reverse sarcopenia (muscle wasting) and related impairments and functional limitations in elderly people. This project addresses the question, "Is high-force eccentric exercise training well tolerated by the elderly, and will it result in improved muscle size, strength, balance, and fall risk?"

Twenty-one frail elderly subjects (mean age, 80 years) experienced 11 weeks of lower-extremity resistance training. The experimental eccentric (ECC) group (n=11) performed negative work while exercising on a high-force eccentric ergometer powered by a 3-hp motor that drives the pedals in a backward rotation while the resistance is gradually increased. The active control group performed traditional (TRAD) (n=10) lower-extremity resistance exercises (weight training). Muscle fiber cross-sectional area and strength, balance, stair-descending abilities, and fall risk were assessed prior to and following the intervention.

The ECC group completed the study and reported the eccentric training (negative work) to be relatively effortless and had minimal and transient muscle soreness. Both groups experienced a significant increase in muscle fiber cross-sectional area (ECC=60%, TRAD=41%). Only the ECC group had significant improvements in strength (60%), balance (7%), and stair descent (21%) abilities. The Timed Up & Go task improved in both groups, but only the ECC group went from a high to low fall risk.

These results are important to physical therapists because they demonstrate that eccentric training (negative work) can improve muscle structure and function in those with limited exercise tolerance. Because low energy expenditure is coupled with high-force production in eccentric training (negative work), this intervention may be useful for a number of patients that are otherwise unable to achieve high muscle forces with traditional resistance exercise.

Dr LaStayo received a PODS II doctoral scholarship in 1999 and a NIFTI fellowship in 2000 from the Foundation. For further information see the following: LaStayo PC, Ewy GA, Pierotti DD, Johns RK, Lindstedt S. The positive effects of negative work: increased muscle strength and decreased fall risk in a frail elderly population. J Gerontology A Biol Sci Med Sci. 2003;58: M419-M424.