Introduction Motor control (MC) is an aspect of physical function that is directly related to neuromuscular function, which can be defined as the production of purposeful and coordinated movement (1), and effective MC relies upon successful communication between the motor nerve and muscle at the neuromuscular junction (NMJ). The effect of various methods of feeding on aspects of physical performance is well established, particularly in a sporting context, however the effects of feeding status on MC and NMJ transmission stability are less apparent. Methods 8 healthy young adults (3 male; age, 27±9 years; BMI, 23.46± 6.02 kg.m2) underwent a battery of neuromuscular assessments, pre and post ingestion of a standardised low glycaemic index mixed carbohydrate meal, normalised to body mass. Strength and power were assessed via isometric maximal voluntary contraction (MVC) of the knee extensors and accelerometery of a squat jump. Force steadiness measures were taken from isometric tracing of an oscillating target fluctuating around 25% (±4%) of their MVC, referred to as complex force tracking. Deviation from the target line was used as a measure of neuromuscular control. Needle electrodes and intramuscular electromyography were used to sample individual motor units (MU) from the Vastus lateralis (VL) during isometric contractions, and NMJ transmission stability was calculated based on the variability of consecutively occurring MU potentials emanating from the same MU (2). Fasted and fed parameters were compared using paired t-tests and significance was accepted at p<0.05. Results Isometric MVC decreased by 15% post feeding (502.25±259.75 vs. 430.79±261.22, p=0.0045), with no significant difference in the power produced from a jump squat post feed (p=0.17). Feeding significantly increased complex force tracking by 20% (39.09±25.05 vs. 29.52±9.55, p=0.035) when measured at 25% of MVC. There was no significant difference in NMJ transmission stability from fasted to fed status (p=0.135). Conclusion These results show an increased level of control in complex force tracking of the knee extensors in the fed state when compared to fasted, demonstrating an improvement in motor control. These effects do not appear to be mediated by improved nerve-muscle communication as assessed via NMJ transmission stability. Further research is needed at additional contraction levels, and in other muscles contributing to knee extensor function to conclude the effect of feeding on MC.
Future Physiology 2020 (Virutal) (2020) Proc Physiol Soc 46, PC0157
Poster Communications: Determining the effects of feeding status on motor nerve characteristics and neuromuscular performance in healthy young individuals
Sarah Miller1
1 School of Agriculture, Food Science and Veterinary Medicine, University College Dublin, Dublin, Ireland
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Where applicable, experiments conform with Society ethical requirements.