Abstract
This study compared traditional (TP) and daily undulating (DUP) periodization on muscle
strength, EMG-estimated neural drive and muscle architecture of the quadriceps femoris
(QF). 10 non-athletic females (24.4±3.2 years) performed 14 weeks of isometric training
for the QF exercising 1 leg using TP and the contralateral leg using DUP. Intensities
varied from 60% to 80% of MVC and the intensity zones and training volume were equated
for each leg. Knee extension MVC, maximal voluntary QF-EMG activity and vastus lateralis
(VL) muscle architecture were measured in both legs before, after 6 weeks and after
14 weeks of training using dynamometry, surface EMG and ultrasonography. Isometric
MVC and maximal QF-EMG remained unaltered after 6 weeks of training, but were significantly
(P<0.05) enhanced after 14 weeks in both legs (MVC: TP 24%, DUP 23%; QF-EMG: TP 45%,
DUP 46%). VL-architecture remained unchanged following 6 weeks of training, but VL-muscle
thickness (TP 17%, DUP 16%) and fascicle length (TP 16%, DUP 17%) displayed significant
(P<0.05) enlargements after 14 weeks in both legs. Importantly, these temporal neuromuscular
alterations displayed no significant differences between the training legs. Therefore,
periodization may not act as a key trigger for neuromuscular adaptations.
Key words
muscle plasticity - quadriceps femoris - EMG - ultrasonography