Abstract
This study examined the effects of constant or variable external resistance training
on neuromuscular adaptations in the lower limbs of older men. 37 subjects (age 65±4 year)
were quasi-randomly assigned to the constant or variable training group, or a non-training
control group. Training consisted of a 20-week medium-intensity, high volume resistance
training program. Maximum bilateral concentric and isometric force production of the
leg extensors as well as repetitions-to-failure test were performed pre-, mid- and
post-training. Vastus lateralis muscle cross-sectional area was assessed by ultrasound
and lean leg mass was assessed by dual-energy x-ray absorptiometry. Both training
groups significantly increased force production of the leg extensors (variable: 26 kg,
95% CI=12–39, P<0.01; constant: 31 kg, 95% CI=19–43, P<0.01) and VL cross-sectional
area (variable: 1.5 cm2, 95% CI=0.03–3.1, P=0.046; constant: 3 cm2, 95% CI=1.2–4.8, P=0.002). However, only the variable training group significantly
improved repetitions to failure performance (704 kg, 95% CI=45–1 364, P=0.035). Only
the variable resistance training group improved fatigue-resistance properties, which
may be an important adaptation to maintain exercise and functional capacity in older
individuals.
Key words
force production - hypertrophy - neural adaptation - quadriceps
