Maximal intended velocity enhances strength training-induced neuromuscular stimulation in older adults

Abstract

The age-related attenuation in neuromuscular function can be mitigated with strength training. Current recommendations for untrained and elderly recommend performing the strength training with a controlled movement velocity (CON). However, applying maximal intended velocity (MIV) in the concentric phase of movement may augment neuromuscular stimulation and potentially enhance training adaptations. Thus, applying rate of electromyography (EMG) rise (RER) recordings, we examined the acute early phase neuromuscular response to these two contraction types in quadriceps femoris during leg extension, along with actual movement velocity, in 12 older (76 ± 6 years) and 12 young men (23 ± 2 years). Results revealed that older adults had a lower one repetition maximum (1RM) than young (33 ± 9 kg vs. 50 ± 9 kg; p = 0.001) and lower actual velocity across relative intensities of ~ 10%, 30%, 50%, 70% and 90% of 1RM for CON and MIV (all p < 0.05). Older adults also had consistently reduced RER compared to young during both conditions (old: 1043–1810 μV; young: 1844–3015 μV; all p < 0.05). However, RER was higher in contractions with MIV compared to CON for both age groups, and across all intensities (98–674%, all p < 0.05). In conclusion, despite decreased maximal strength and attenuated neuromuscular response with advancing age, our results document an augmented neuromuscular activation when repetitions are performed with MIV in the concentric phase of movement.

Effects of Eccentric Phase Velocity on Bench Press Concentric Bar Velocity in the Young and Elderly

“…The sample size calculation was performed using the software G*power (3.1.9.4, University of Kiel, Germany), based on a previous study that investigated MPV in 24 participants, including 12 elderly (76 + 6 years) and 12 young women (23 + 2 years). Considering two groups, four repeated measures, and a correlation of 0.5, to achieve a statistical power of 0.80 and a mean F-effect of 0.50, it was determined that a sample of 24 subjects was necessary [18]. The participants were recruited through advertisements on social media using non-probability sampling and were informed about the benefits and potential risks of the study through the consent form.…”

Sit-to-Stand Power Is a Stronger Predictor of Gait Speed than Knee Extension Strength

“…Indeed, muscle power is a strong predictor of all-cause mortality, physical function, and mobility outcomes in aging adults [ 20 , 21 , 22 , 23 ]. Given that power training enhances voluntary skeletal muscle activation [ 24 , 25 ], which is longitudinally associated with improvements in gait speed [ 26 ], it seems clear there is a strong, causal link between muscle power and gait performance/mobility. Indeed, similar to strength, resistance exercise-induced increases in lower-extremity power are associated with clinically meaningful changes in UGS [ 23 ], and power training is effective at increasing gait speed in both healthy and mobility-limited populations [ 27 , 28 ].…”