AUTHOR=Watanabe Kohei , Holobar Aleš , Mita Yukiko , Kouzaki Motoki , Ogawa Madoka , Akima Hiroshi , Moritani Toshio 

TITLE=Effect of Resistance Training and Fish Protein Intake on Motor Unit Firing Pattern and Motor Function of Elderly

JOURNAL=Frontiers in Physiology

VOLUME=Volume 9 - 2018

YEAR=2018

URL=https://www.frontiersin.org/journals/physiology/articles/10.3389/fphys.2018.01733

DOI=10.3389/fphys.2018.01733

ISSN=1664-042X

ABSTRACT=We investigated the effect of resistance training and fish protein intake on the motor unit firing pattern and motor function in elderly.  Fifty healthy elderly males and females (69.2 ± 4.7 years) underwent 6 weeks of intervention.  We applied the leg-press exercise as resistance training and fish protein including Alaska pollack protein (APP) as nutritional supplementation.  Subjects were divided into four groups: fish protein intake without resistance training (APP-CN, n=13), placebo intake without resistance training (PLA-CN, n=12), fish protein intake with resistance training (APP-RT, n=12), and placebo intake with resistance training (PLA-RT, n=13).  Motor unit firing rates were calculated from multi-channel surface electromyography by the Convolution Kernel.  A greater improvement in the motor function, i.e., chair-stand test, was observed in APP-RT compared with PLA-RT at 6W (p < 0.05).  Changes in the motor unit firing pattern were mainly noted within motor units with a low-recruitment threshold in APP-RT and PLA-RT at 3 and 6W (p < 0.05), but not in APP-CN or PLA-CN (p > 0.05).  Time courses of changes in the results of the chair-stand test and motor unit firing rate were different between APP-RT and PLA-RT.  These findings suggest that, in the elderly, the effect of resistance training on the motor unit firing rate is observed in motor units with a low-recruitment threshold, and additional fish protein intake modifies these changes in motor unit firing patterns and the motor function following resistance training.