Medical Express

ISSN (print): 2318-8111

ISSN (online): 2358-0429

Author's Articles

2 result(s) for: Alberto Souza de Sá Filho

Involvement of beta absolute power in motor areas after hand immobilization: An EEG study

Dionis Machado; Jadna Helena dos Santos França; Silmar Teixeira; Victor Hugo do Vale Bastos; Maurício Cagy; Alberto Souza de Sá Filho; Sérgio Machado; Bruna Velasques; Pedro Ribeiro


Abstract PDF

OBJECTIVE: The purpose of this study was to analyze changes in beta band absolute power in cortical areas, before and after a condition of hand immobilization for 48 hours.
METHOD: Fifteen healthy volunteers, aged between 20 and 30, were submitted to EEG assessment before and after immobilization, while performing a motor task triggered by a visual stimulus.
RESULTS: Statistical analysis revealed that hand immobilization caused changes in cortical areas. Significant increases in beta band absolute power were found after hand immobilization at electrodes Fp2, C3 and P4. In contrast, at electrode C4 a decrease in beta band absolute power occurred after hand immobilization.
CONCLUSION: Predominant hand immobilization, even for 48 hours, is sufficient to cause cortical changes that affect movement planning. Such changes may represent a cortical strategy to supply cortical changes in contralateral hemisphere due to immobilization. Further studies are necessary to understand cortical changes due to hand immobilization and movement planning, especially considering how much time of immobilization is necessary to promote such changes.

Keywords: Beta band, Hand immobilization, Neural plasticity, Electroencephalography.

Analysis of Reliability of Peak Treadmill Running in Maximum Progressive Effort Test: Influence of Training Level

Alberto Souza de Sá Filho; Wendel Alves; Thiago Gottgtroy Miranda; Eduardo Portuga; Sérgio Machado


Abstract PDF

OBJECTIVE: To determine the reliability (stability) of the peak velocity measurement (VPeak) derived from the incremental maximal effort test, as well as to establish the possible influence of the level of training on these responses.
METHOD: Thirty-eight male volunteers made two visits (3 - 5 days apart) to the training center where the study was conducted and performed maximal progressive running tests. The protocol consisted of increments of 0.5 km.h-1/min, starting at a running speed comfortable for each participant (7-9 km.h-1). All subjects were encouraged to achieve the maximum possible performance in both tests, with final voluntary exhaustion being the criterion for interruption.
RESULTS: The intra-class correlation coefficient presented excellent consistency of measurements (ICC = 0.975 - p = 0.001). The typical relative error of the measurement was 2.6% for the stability of the measurement of VPeak. Moreover, there were no significant differences between the individual coefficients of variation for measures 1 vs. 2 (p > 0.05). Graphical representation of Bland-Altman demonstrated a homogeneous distribution of the measurement error for all dependent variables.
CONCLUSION: Determination of VPeak exhibited excellent levels of reliability with small measurement errors. There was no influence of the training level on the reliability responses.

Keywords: Reliability; VO<sub>2Max</sub>; Aerobic Exercise; Aerobic Performance.