The Positive Effects of Negative Work: Increased Muscle Strength and Decreased Fall Risk in a Frail Elderly Population

TLDR

The study aimed to determine whether chronic eccentric (negative work) training could prevent or reverse sarcopenia and its functional limitations in frail elderly individuals. Twenty‑one frail elders (mean age 80) completed 11 weeks of lower‑extremity resistance training, with 11 participants performing high‑force eccentric work on an ergometer and 10 performing traditional weight training, while muscle fiber cross‑sectional area, strength, balance, stair descent, and fall risk were assessed before and after the intervention. Eccentric training produced a 60 % increase in muscle fiber CSA versus 41 % in the control group, and led to significant gains in strength, balance, stair descent, and a shift from high to low fall risk, whereas the traditional group showed improvements only in muscle CSA and the timed up‑and‑go task.

Abstract

The objective of this study was to determine if a chronic eccentric training intervention, i.e., negative work, could limit or even reverse sarcopenia and its related impairments and functional limitations. Is high-force eccentric training tolerable by elderly people and will it result in improved muscle size, strength, balance, and fall risk?21 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. The active "controls" 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 this intervention.All ECC subjects who started the negative work intervention completed the study and reported the training to be relatively effortless; they experienced 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 experienced significant improvements in strength (60%), balance (7%), and stair descent (21%) abilities. The timed up and go task improved in both groups, but only the ECC group went from a high to a low fall risk.These data demonstrate that lower extremity resistance exercise can improve muscle structure and function in those with limited exercise tolerance. The greater strength increase following negative work training resulted in improved balance, stair descent, and fall risk only in the ECC group. Because low energy cost is coupled to high force production with eccentric exercise, this intervention may be useful for a number of patients that are otherwise unable to achieve high muscle forces with traditional resistance exercise.