@misc{10481/91613,
year = {2023},
month = {12},
url = {https://hdl.handle.net/10481/91613},
abstract = {Most of the existing research has focused on jump plyometrics, where landing reaction
forces must be dissipated among lower limb articulations. In contrast, the investigation of resisted
plyometrics without jumping, devoid of such landing forces, remains relatively limited. This study
aimed to (i) investigate the impact of resisted plyometrics without jumping at two knee flexion
angles (60 and 90 degrees) on vastus muscle activity relative to limb dominance and (ii) assess
strength, power, and work during the concentric–eccentric phases of these exercises. Thirty-one
healthy participants underwent quantification of lower limb muscle amplitude, strength, power, and
work during resisted plyometrics without jumping from both 60º and 90º knee flexion positions.
After anthropometric evaluations, participants used a dynamometer with a load equal to 80% of
body weight while wireless surface electromyography electrodes recorded data. Statistical analyses
utilized paired t-tests or nonparametric equivalents and set significance at p ≤ 0.05. Results showed
significantly higher muscle activity in the vastus medialis (VM) (dominant: 47.4%, p = 0.0008, rs = 0.90;
nondominant: 54.8%, p = 0.047, rs = 0.88) and vastus lateralis (VL) (dominant: 46.9%, p = 0.0004,
rs = 0.86; nondominant: 48.1%, p = 0.021, rs = 0.67) muscles when exercises started at 90º knee
flexion, regardless of limb dominance. Substantial intermuscle differences occurred at both 60º
(50.4%, p = 0.003, rs = 0.56) and 90º (54.8%, p = 0.005, rs = 0.62) knee flexion, favoring VM in the
nondominant leg. Concentric and eccentric strength, power, and work metrics significantly increased
when initiating exercises from a 90º position. In conclusion, commencing resisted plyometrics
without jumping at a 90º knee flexion position increases VM and VL muscle activity, regardless of
limb dominance. Furthermore, it enhances strength, power, and work, emphasizing the importance of
knee flexion position customization for optimizing muscle engagement and functional performance.},
publisher = {MDPI},
keywords = {Plyometric},
keywords = {Electromyography},
keywords = {Dynamometry},
title = {Impact of Starting Knee Flexion Angle on Muscle Activity and Performance during Plyometrics without Jumping},
doi = {10.3390/s24010044},
author = {Torres Banduc, Maximiliano A. and Chirosa Ríos, Ignacio Jesús and Chirosa Ríos, Luis Javier and Jerez Mayorga, Daniel Alejandro},
}