A Combined Muscle Model and Wavelet Approach to Interpreting the Surface EMG Signals From Maximal Dynamic Knee Extensions

Forrester, Stephanie E.; Pain, Matthew T. G.
February 2010
Journal of Applied Biomechanics;Feb2010, Vol. 26 Issue 1, p62
Academic Journal
This study aimed to identify areas of reduced surface EMG amplitude and changed frequency across the phase space of a maximal dynamic knee extension task. The hypotheses were that (1) amplitude would be lower for eccentric contractions compared with concentric contractions and unaffected by fiber length and (2) mean frequency would also be lower for eccentric contractions and unaffected by fiber length. Joint torque and EMG signals from the vasti and rectus femoris were recorded for eight athletic subjects performing maximum knee extensions at 13 preset crank velocities spanning ±300°·s-1. The instantaneous amplitude and mean frequency were calculated using the continuous wavelet transform time-frequency method, and the fiber dynamics were determined using a muscle model of the knee extensions. The results indicated that (1) only for the rectus femoris were amplitudes significantly lower for eccentric contractions (p = .019) and, for the vasti, amplitudes during eccentric contractions were less than maximal but this was also the case for concentric contractions due to a significant reduction in amplitude toward knee extension (p = .023), and (2) mean frequency increased significantly with decreasing fiber length for all knee extensors and contraction velocities (p = .029). Using time—frequency processing of the EMG signals and a muscle model allowed the simultaneous assessment of fiber length, velocity, and EMG.


Related Articles

  • Interdependence of torque, joint angle, angular velocity and muscle action during human multi-joint leg extension. Hahn, Daniel; Herzog, Walter; Schwirtz, Ansgar // European Journal of Applied Physiology;Aug2014, Vol. 114 Issue 8, p1691 

    Purpose: Force and torque production of human muscles depends upon their lengths and contraction velocity. However, these factors are widely assumed to be independent of each other and the few studies that dealt with interactions of torque, angle and angular velocity are based on isolated...

  • INCOMPLETE POSTURE ADJUSTMENT DURING RAPID ARM MOVEMENT. Yamasaki, Hiroshi; Hoshi, Fumihiko; Fujisawa, Hiroyuki; Nagasaki, Hiroshi // Perceptual & Motor Skills;Jun2009, Vol. 108 Issue 3, p915 

    It is not well understood how posture (nonfocal joints) is stabilized during rapid joint movements. Interaction torque arising at the joints due to the movement of the adjacent joints will disturb the nonlocal joint unless it is compensated by muscle torque. The aim of this study was to clarify...

  • Mechanomyographic and Electromyographic Responses During Fatiguing Eccentric Muscle Actions of the Leg Extensors. Camic, Clayton L.; Housh, Terry J.; Zuniga, Jorge M.; Bergstrom, Haley C.; Schmidt, Richard J.; Johnson, Glen O. // Journal of Applied Biomechanics;Apr2014, Vol. 30 Issue 2, p255 

    The purpose of the current study was to examine the patterns of responses for torque, mechanomyographic (MMG) amplitude, MMG frequency, electromyographic (EMG) amplitude, and EMG frequency across 30 repeated maximal eccentric muscle actions of the leg extensors. Eleven moderately trained females...

  • Gymnasts and non-athletes muscle activation and torque production at the ankle joint. Albuquerque Goulart, Natália Batista; Pieta Dias, Caroline; de Aguiar Lemos, Fernando; Geremia, Jeam Marcel; Oliva, João Carlos; Vaz, Marco Aurélio // Brazilian Journal of Kineanthropometry & Human Performance;2014, Vol. 16 Issue 5, p555 

    Artistic Gymnasts (AG) execute specific movements that require substantial movement control and force production at the ankle joint. This high demand might change the neuromechanical properties of the ankle joint muscles in these athletes compared to non-athlete girls (NAG). The aim of this...

  • Relationship between joint passive stiffness and hip lateral rotator concentric torque. Leite, Diego X.; Vieira, Jean M. M.; Carvalhais, Viviane O. C.; Araújo, Vanessa L.; Silva, Paula L. P.; Fonseca, Sérgio T. // Brazilian Journal of Physical Therapy / Revista Brasileira de Fi;set/out2012, Vol. 16 Issue 5, p414 

    Background: Adequate passive stiffness of the hip joint can prevent the occurrence of excessive transverse plane lower limb movement during functional activities. Strength training of the hip lateral rotator muscles can be used to increase the stiffness of this joint. However, the relationship...

  • Influence of Knee Joint Position on Co-contractions of Agonist and Antagonist Muscles during Maximal Voluntary Isometric Contractions: Electromyography and Cybex Measurement. Zhang Qi // Journal of Physical Therapy Science;2007, Vol. 19 Issue 2, p125 

    The article presents a study which investigated the effect of using different angles of knee joint on the activation level of agonist and antagonist muscles during isometric efforts. The study employed 10 healthy subjects that were subjected to electromyographic activities and isometric torque...

  • Deliberate utilization of interaction torques brakes elbow extension in a fast throwing motion. Hore, Jon; Debicki, Derek; Gribble, Paul; Watts, Sherry // Experimental Brain Research;May2011, Vol. 211 Issue 1, p63 

    We tested the hypothesis that in fast arm movements the CNS deliberately utilizes interaction torques to decelerate (brake) joint rotations. Twelve subjects performed fast 2-D overarm throws in which large elbow extension velocities occurred. Joint motions were computed from recordings made with...

  • Biomechanics of Off-Center Monoarticular Exercises With Lever Selectorized Equipment. Biscarini, Andrea // Journal of Applied Biomechanics;Feb2010, Vol. 26 Issue 1, p73 

    We have developed a 2-D analytical biomechanical model for monoarticular open kinetic-chain exercises with lever selectorized equipment, and different relative placement between the joint center of rotation (J) and the center of rotation (C) of the resistance input lever ("off-center"...

  • The Effect of Hip Bracing on Gait in Patients with Medial Knee Osteoarthritis. Wallace, David; Barr, Christa // Arthritis (20901984);2012, p1 

    Objective. Impaired hip motion has been associated with heightened medial knee joint loading in patients with knee osteoarthritis (OA). A hip external rotation strap designed to pull the femur into external rotation and abduction may serve as one protective mechanism. The primary aim of our...


Read the Article


Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics