EEG Measures of Cortical Activity with Different Types of Acute Resistance Exercise Workouts.

PURPOSE: To date no study has examined the influence of different types of resistance exercise workouts on EEG cortical activity in the brain. The purpose of this study was to uncover topographical characteristics of cortical activity during different resistance exercise (RE) bouts comprised of different combinations of the acute program variables. METHODS: Four resistance training protocols were chosen based on their differential interaction with force production: high power (PWR, 6×3 squat jumps at 30% of 1RM); high force (FORCE, 6×3 squat at 95% of 1RM); high volume (oL, 6×10 at 80% of their 1RM); and a control day (CTRL, 6 sets of unracking an empty bar). To control for the rate of adaptation, only highly trained male subjects (years of training: 6+/-1 yrs; squat 1RM: 174+/-26 kg; age: 22+/-3 yrs; body mass: 84.76+/-9.86 kg; n = 7) were included in this study. Cortical activity was measured using an Ag-AgCl electrode-cap, a 40-channel monopolar digital amplifier, and an expanded International 10-20 electrode placement. Linked-ears reference, a ground scalp electrode, and eye electrodes were used to account for electrical artifacts (facial contractions). Movement artifacts were removed using a spatial filter. A 32-bit analog-to-digital converter was used to digitize signals at a sampling rate of 1000hz. High and low frequency bandpass was set at DC and 100hz respectively and signals were low-pass filtered at 50hz using an Infinite Impulse Response (IIR) recursive filter set to a roll-off of 12dB/oct. Pearson product-moment correlation coefficients were determined for selected pair wise variables. One-way and univariate analyses of variance (ANOVA) with repeated measures and Fisher's LSD post-hocs were used to detect significant mean differences. Significance level in this study was set at a 0.05 alpha level. RESULTS: Digital EEG techniques provided visual maps of the motor related cortical potential activity (MRCP) during each repetition of exercise. MRCP alterations were observed in all RE protocols when compared to CTRL, but our findings were not confined to the motor cortex. Each protocol was accompanied by specific yet characteristic MRCP patterns. As expected, the CTRL protocol was accompanied by little activity that was diffusely spread. Integral mapping showed activity increases in PWR, FORCE, and oL. These changes were primarily seen in prefrontal, central, posterior parietal, and occipital cortical regions, although the magnitude and temporal characteristics of activity appeared to vary. Therefore, the primary finding of this investigation was that, as assessed by high density EEG, cortical activity during maximal exertion resistance exercise incorporating large amounts of muscle mass in highly trained males is specific to the physical characteristics of movement and global in nature. CONCLUSIONS: In the present study, the visual maps of motor related cortical potential suggest that the differing domains of resistance exercise are characterized by unique topographical characteristics. PRACTICAL APPLICATIONS. The finding that different exercise domains are stimulated by unique cortical output signifies the importance of the acute program variables to physical development in trained men. Based on the images we were able to produce, it is possible that the concept of the size principle is reflected in distinct patterns at the level of the motor cortex. The role of the central nervous system in the control of physiological function cannot be underestimated, and this study should be placed appropriately within the context of this evolving area of research. [ABSTRACT FROM AUTHOR]