Effects of once- versus twice-weekly eccentric resistance training on muscular function and structure in older adults: a randomised controlled trial

Abstract

Adherence rates to current twice-weekly strength training guidelines are poor among older adults. Eccentric-only training elicits substantial improvements in muscle function/size so the aim of this study was to compare the effects of once- versus twice-weekly eccentric training programmes on muscle function/size in older adults. Thirty-six participants (69.4 ± 6.0 yr) were randomised into non-active control, once-, or twice-weekly training groups. Lower-limb muscle power, strength, and size were assessed at baseline, mid-, and post-eccentric training. Training was performed for 12 min per session at 50% of maximum eccentric strength. Significant increases in power (13%), isometric (17–36%) and eccentric (40–50%) strength, and VL muscle thickness (9–18%) occurred in both training groups following 12 weeks. Minimal muscle soreness was induced throughout the 12 weeks and perceived exertion was consistently lower in the twice-weekly training group. One weekly submaximal eccentric resistance training session over 12 weeks elicits similar improvements in neuromuscular function compared to the currently recommended twice-weekly training dose. Given the substantial improvements in neuromuscular function and previously reported low adherence to current twice-weekly training guidelines, eccentric training may be pivotal to developing a minimal-dose strategy to counteract neuromuscular decline. The trial was registered retrospectively on 24/01/2024 with ISRCTN (trial registration number: ISRCTN68730580).

Submaximal eccentric resistance training increases serial sarcomere number and improves dynamic muscle performance in old rats

“…Since eccentric contraction-induced muscle damage is more prevalent with increasing contraction intensity (25), and old rats take longer to recover from damage (19), sarcomerogenesis was likely blunted due to accumulation of muscle damage and insufficient recovery between each training session. The present study aimed to determine whether a submaximal (60% of maximum torque) eccentric training stimulus would better increase SSN and improve mechanical function in old rats, as suggested by studies on humans using loads equivalent to 50-80% of 1-repetition maximum (14)(15)(16)26).…”