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RESEARCH PRODUCT

Electromyostimulation Training Effects on Neural Drive and Muscle Architecture

Marie GuetteYves BallayAlain MartinJulien Gondin

subject

Malemedicine.medical_specialtyKnee extensorsmedicine.diagnostic_testElectromyographybusiness.industryVastus medialisReproducibility of ResultsPhysical Therapy Sports Therapy and RehabilitationMuscle activationElectromyographyAnatomyIsometric exercisemusculoskeletal systemElectric StimulationMuscle hypertrophyPhysical medicine and rehabilitationHumansMedicineOrthopedics and Sports MedicineFranceMuscle SkeletalTraining programbusinessMuscle architecture

description

GONDIN, J., M., GUETTE, Y. BALLAY, and A. MARTIN. Electromyostimulation Training Effects on Neural Drive and Muscle Architecture. Med. Sci. Sports Exerc., Vol. 37, No. 8, pp. 1291–1299, 2005. Purpose: The purpose of the study was to investigate the effect of 4 and 8 wk of electromyostimulation (EMS) training on both muscular and neural adaptations of the knee extensor muscles. Methods: Twenty males were divided into the electrostimulated group (EG, N 12) and the control group (CG, N 8). The training program consisted of 32 sessions of isometric EMS over an 8-wk period. All subjects were tested at baseline (B) and retested after 4 (WK4) and 8 (WK8) wk of EMS training. The EMG activity and muscle activation obtained under maximal voluntary contractions (MVC) was used to assess neural adaptations. Torque and EMG responses obtained under electrically evoked contractions, muscle anatomical cross-sectional area (ACSA), and vastus lateralis (VL) pennation angle, both measured by ultrasonography imaging, were examined to analyze muscular changes. Results: At WK8, knee extensor MVC significantly increased by 27% (P 0.001) and was accompanied by an increase in muscle activation (6%, P 0.01), quadriceps muscle ACSA (6%, P 0.001), and VL pennation angle (14%, P 0.001). A significant increase in normalized EMG activity of both VL and vastus medialis (VM) muscles (69 and 39%, respectively, P 0.001) but not of rectus femoris (RF) muscle was also found at WK8. The ACSA of the VL, VM, and vastus intermedius muscles significantly increased at WK8 (5–8%, P 0.001) but not at WK4, whereas no changes occurred in the RF muscle. Conclusion: We concluded that the voluntary torque gains obtained after EMS training could be attributed to both muscular and neural adaptations. Both changes selectively involved the monoarticular vastii muscles. Key Words: STRENGTH GAINS, EMG ACTIVITY, MUSCLE ACTIVATION, HYPERTROPHY, KNEE EXTENSORS

https://doi.org/10.1249/01.mss.0000175090.49048.41