Four weeks of high cadence training alter brain cortical activity in cyclists

ABSTRACT

Exercise at different cadences might serve as potential stimulus for functional adaptations of the brain, because cortical activation is sensitive to frequency of movement. Therefore, we investigated the effects of high (HCT) and low cadence training (LCT) on brain cortical activity during exercise as well as endurance performance.

Cyclists were randomly assigned to low and high cadence training. Over the 4-week training period, participants performed 4 h of basic endurance training as well as four additional cadence-specific exercise sessions, 60 min weekly. At baseline and after 4 weeks, participants completed an incremental exercise test with spirometry and exercise at constant load with registration of electroencephalogram (EEG).

Compared with LCT, a greater increase of frontal alpha/beta ratio was confirmed in HCT. This was based on a lower level of beta activity during exercise. Both groups showed similar improvements in maximal oxygen consumption and power at the individual anaerobic threshold.

Whereas HCT and LCT elicit similar benefits on aerobic performance, cycling at high pedalling frequencies enables participants to perform an exercise bout with less cortical activation.     

Development of raw acceleration cut-points for wrist and hip accelerometers to assess sedentary behaviour and physical activity in 5–7-year-old children

ABSTRACT

This study validated sedentary behaviour (SB), moderate-to-vigorous physical activity (MVPA) and vigorous physical activity (VPA) accelerometer cut-points in 5–7-year-old children. Participants (n = 49, 55% girls) wore an ActiGraph GT9X accelerometer, recording data at 100 Hz downloaded in 1 s epochs, on both wrists and the right hip during a standardised protocol and recess. Cut-points were generated using ROC analysis with direct observation as a criterion. Subsequently, cut-points were optimised using Confidence intervals equivalency analysis and then cross-validated in a cross-validation group. SB cut-points were 36 mg (Sensitivity (Sn) = 79.8%, Specificity (Sp) = 56.8%) for non-dominant wrist, 39 mg (Sn = 75.4%, Sp = 70.2%) for dominant wrist and 20 mg (Sn = 78%, Sp = 50.1%) for hip. MVPA cut-points were 189 mg (Sn = 82.6%, Sp = 78%) for non-dominant wrist, 181 mg (Sn = 79.1%, Sp = 76%) for dominant wrist and 95 mg (Sn = 79.3%, Sp = 75.6%) for hip. VPA cut-points were 536 mg (Sn = 75.1%, Sp = 68.7%) for non-dominant wrist, 534 mg (Sn = 67.6%, Sp = 95.6%) for dominant wrist and 325 mg (Sn = 78.2%, Sp = 96.1%) for hip. All placements demonstrated adequate levels of accuracy for SB and PA assessment.     

Utilizing microfluidics to synthesize polyethylene glycol microbeads for F?rster resonance energy transfer based glucose sensing

Here, we utilize microfluidic droplet technology to generate photopolymerizeable polyethylene glycol (PEG) hydrogel microbeads incorporating a fluorescence-based glucose bioassay. A microfluidic T-junction and multiphase flow of fluorescein isothiocyanate dextran, tetramethyl rhodamine isothiocyanate concanavalin A, and PEG in water were used to generate microdroplets in a continuous stream of hexadecane. The microdroplets were photopolymerized mid-stream with ultraviolet light exposure to form PEG microbeads and were collected at the outlet for further analysis. Devices were prototyped in PDMS and generated highly monodisperse 72 ± 2 μm sized microbeads (measured after transfer into aqueous phase) at a continuous flow rate between 0.04 ml/h—0.06 ml/h. Scanning electron microscopy analysis was conducted to analyze and confirm microbead integrity and surface morphology. Glucose sensing was carried out using a Förster resonance energy transfer (FRET) based assay. A proportional fluorescence intensity increase was measured within a 1–10 mM glucose concentration range. Microfluidically synthesized microbeads encapsulating sensing biomolecules offer a quick and low cost method to generate monodisperse biosensors for a variety of applications including cell cultures systems, tissue engineering, etc.     

Neurophysiological correlates of interference control and response inhibition processes in children and adolescents engaging in open- and closed-skill sports

Background:Accumulating evidence suggests that sports participation promotes the development of inhibitory control,but the influences of the sports category and inhibition type still remain unclear.The categorization of sports based on the open-skill(externally paced)and closed-skill(self-paced)continuum allows for the integration of the environment as a factor contributing to sports-related benefits for inhibitory control.Methods:Cross-sectional data from different studies were combined(n=184)to examine the association between open-and closed-skill sports and cognitive control processes related to interference control and response inhibition.Participants(aged 9-14 years)filled in 7-day physical activity recall protocols and completed a Stroop Color-Word or a Go/NoGo task.The N200,N450,and P300 components of event-related potentials elicited by these tasks were recorded using electroencephalography.Results:Partial correlations supported the belief that time spent in open-skill sports was related to higher performance on inhibition trials.Additionally,path analyses revealed an association between this sports type and a greater negativity in the N200 and N450 amplitudes in both the full sample and group-level analyses.In contrast,no relation was found between sports type and P300 amplitude.Conclusion:The findings suggest that only the engagement in open-skill sports is associated with more effective conflict monitoring and higher performance on tasks demanding inhibitory control.