TY - JOUR
T1 - The complexity of H-wave amplitude fluctuations and their bilateral cross-covariance are modified according to the previous fitness history of young subjects under track training
AU - Ceballos-Villegas, Maria E.
AU - Saldaña Mena, Juan J.
AU - Gutierrez Lozano, Ana L.
AU - Sepúlveda-Cañamar, Francisco J.
AU - Huidobro, Nayeli
AU - Manjarrez, Elias
AU - Lomeli, Joel
N1 - Publisher Copyright:
© 2017 Ceballos-Villegas, Saldaña Mena, Gutierrez Lozano, Sepúlveda-Cañamar, Huidobro, Manjarrez and Lomeli.
PY - 2017/11/1
Y1 - 2017/11/1
N2 - The Hoffmann reflex (H-wave) is produced by alpha-motoneuron activation in the spinal cord. A feature of this electromyography response is that it exhibits fluctuations in amplitude even during repetitive stimulation with the same intensity of current. We herein explore the hypothesis that physical training induces plastic changes in themotor system. Such changes are evaluated with the fractal dimension (FD) analysis of the H-wave amplitude-fluctuations (H-wave FD) and the cross-covariance (CCV) between the bilateral H-wave amplitudes. The aim of this study was to compare the H-wave FD as well as the CCV before and after track training in sedentary individuals and athletes. The training modality in all subjects consisted of running three times per week (for 13 weeks) in a concrete road of 5 km. Given the different physical condition of sedentary vs. athletes, the running time between sedentary and athletes was different. After training, the FD was significantly increased in sedentary individuals but significantly reduced in athletes, although there were no changes in spinal excitability in either group of subjects.Moreover, the CCV between bilateral H-waves exhibited a significant increase in athletes but not in sedentary individuals. These differential changes in the FD and CCV indicate that the plastic changes in the complexity of the H-wave amplitude fluctuations as well as the synaptic inputs to the Ia-motoneuron systems of both legs were correlated to the previous fitness history of the subjects. Furthermore, these findings demonstrate that the FD and CCV can be employed as indexes to study plastic changes in the human motor system.
AB - The Hoffmann reflex (H-wave) is produced by alpha-motoneuron activation in the spinal cord. A feature of this electromyography response is that it exhibits fluctuations in amplitude even during repetitive stimulation with the same intensity of current. We herein explore the hypothesis that physical training induces plastic changes in themotor system. Such changes are evaluated with the fractal dimension (FD) analysis of the H-wave amplitude-fluctuations (H-wave FD) and the cross-covariance (CCV) between the bilateral H-wave amplitudes. The aim of this study was to compare the H-wave FD as well as the CCV before and after track training in sedentary individuals and athletes. The training modality in all subjects consisted of running three times per week (for 13 weeks) in a concrete road of 5 km. Given the different physical condition of sedentary vs. athletes, the running time between sedentary and athletes was different. After training, the FD was significantly increased in sedentary individuals but significantly reduced in athletes, although there were no changes in spinal excitability in either group of subjects.Moreover, the CCV between bilateral H-waves exhibited a significant increase in athletes but not in sedentary individuals. These differential changes in the FD and CCV indicate that the plastic changes in the complexity of the H-wave amplitude fluctuations as well as the synaptic inputs to the Ia-motoneuron systems of both legs were correlated to the previous fitness history of the subjects. Furthermore, these findings demonstrate that the FD and CCV can be employed as indexes to study plastic changes in the human motor system.
KW - Alpha-motoneuron
KW - Amplitude fluctuation
KW - Complexity
KW - Cross-covariance
KW - Fractal dimension
KW - H-wave
UR - http://www.scopus.com/inward/record.url?scp=85041003423&partnerID=8YFLogxK
U2 - 10.3389/fnhum.2017.00530
DO - 10.3389/fnhum.2017.00530
M3 - Artículo
AN - SCOPUS:85041003423
SN - 1662-5161
VL - 11
JO - Frontiers in Human Neuroscience
JF - Frontiers in Human Neuroscience
M1 - 530
ER -