Faculty Collaboration Database

Fatigability of the knee extensor muscles during high-load fast and low-load slow resistance exercise in young and older adults. Exp Gerontol 2021 Oct 15;154:111546

Date

09/08/2021

Pubmed ID

34492255

Pubmed Central ID

PMC8572584

DOI

10.1016/j.exger.2021.111546

Scopus ID

2-s2.0-85114770518 (requires institutional sign-in at Scopus site)   5 Citations

Abstract

Resistance exercise training is a cornerstone in preventing age-related declines in muscle mass and strength, and fatigability of limb muscle is important to this adaptive response. It is unknown, however, whether fatigability and the underlying mechanisms differ between different resistance exercise protocols in young and older adults. The purpose of this study was to quantify the fatigability of the knee extensors and identify the mechanisms in 20 young (22.2 ± 1.3 yr, 10 women) and 20 older adults (73.8 ± 5.4 yr, 10 women) elicited by a single session of high- and low-load resistance exercise. One leg completed a high-load protocol with contractions performed as fast as possible (HL-fast, ~80% 1 Repetition Max, 1RM), and the contralateral leg a low-load protocol performed with slow contractions (LL-slow, ~30% 1RM, 6 s concentric, 6 s eccentric). Each exercise involved four sets of eight repetitions. Before and immediately following each set, maximal voluntary isometric contractions (MVC) were performed, and voluntary activation and contractile properties quantified using electrical stimulation. The reduction in MVC was greater following the LL-slow (20%) than the HL-fast (12%, P = 0.004), with no age or sex differences. Similarly, the reduction in the amplitude of the involuntary electrically-evoked twitch was greater in the LL-slow (14%) than the HL-fast (7%, P = 0.014) and correlated with the reduction in MVC (r = 0.546, P < 0.001), whereas voluntary activation decreased only for the LL-slow protocol (5%, P < 0.001). Thus, low-load resistance exercise with slow contractions induced greater fatigability within the muscle than a more traditional high-load resistance protocol for both young and older men and women.

Author List

Delgadillo JD, Sundberg CW, Kwon M, Hunter SK

Author

Chrisopher Sundberg in the CTSI department at Medical College of Wisconsin - CTSI

MESH terms used to index this publication - Major topics in bold

Aged
Female
Humans
Isometric Contraction
Knee
Male
Muscle Fatigue
Muscle, Skeletal
Resistance Training