Biomaterial Database

Muscle sympathetic nerve activity during intermittent handgrip exercise. 2012

T Hachiya, and S Aizawa, and A P Blaber, and M Saito

Laboratory of Applied Physiology, Toyota Technological Institute, Nagoya 468-0511, Japan. thachiya@hotmail.com

OBJECTIVE This study evaluated whether central command plays an important role in activating muscle sympathetic nerve activity (MSNA) during short-term maximal handgrip contractions. METHODS The increase in MSNA was examined while influence of minimizing for other factors such as mechanoreflex, metaboreflex and fatigue during repetitive exercise in seven 19- to 26-year-old participants. Maximal voluntary handgrips (15-s contraction with a 45-s relaxation) were performed 10 times with a 15-s pause between alternate hands. MSNA was recorded from the tibial nerve analyzed using the burst frequency (BF) and total sympathetic nerve activity. RESULTS The BF increased with the first unit, from 14.9±1.8 bursts·min-1 at baseline to 27.7±3.4 bursts·min-1 during contraction. The increase in the MSNA during contractions remained unchanged throughout the repetitions. The BF declined to baseline during the relaxation periods. The peak grip force decreased from 333±25 N for the first grip to 216±20 N for the last contraction. The MSAN increase remained constant despite a possible reduction in mechanoreflex during exercise as indicated from decreased maximal handgrip force. CONCLUSIONS We suggested that the MSNA response was induced mainly by central command during short-term maximal handgrip contraction without metaboreflex influence and attenuated mechanoreflex input.

UI	MeSH Term	Description	Entries
D007537	Isometric Contraction	Muscular contractions characterized by increase in tension without change in length.	Contraction, Isometric,Contractions, Isometric,Isometric Contractions
D008297	Male		Males
D005260	Female		Females
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000328	Adult	A person having attained full growth or maturity. Adults are of 19 through 44 years of age. For a person between 19 and 24 years of age, YOUNG ADULT is available.	Adults
D013564	Sympathetic Nervous System	The thoracolumbar division of the autonomic nervous system. Sympathetic preganglionic fibers originate in neurons of the intermediolateral column of the spinal cord and project to the paravertebral and prevertebral ganglia, which in turn project to target organs. The sympathetic nervous system mediates the body's response to stressful situations, i.e., the fight or flight reactions. It often acts reciprocally to the parasympathetic system.	Nervous System, Sympathetic,Nervous Systems, Sympathetic,Sympathetic Nervous Systems,System, Sympathetic Nervous,Systems, Sympathetic Nervous
D015444	Exercise	Physical activity which is usually regular and done with the intention of improving or maintaining PHYSICAL FITNESS or HEALTH. Contrast with PHYSICAL EXERTION which is concerned largely with the physiologic and metabolic response to energy expenditure.	Aerobic Exercise,Exercise, Aerobic,Exercise, Isometric,Exercise, Physical,Isometric Exercise,Physical Activity,Acute Exercise,Exercise Training,Activities, Physical,Activity, Physical,Acute Exercises,Aerobic Exercises,Exercise Trainings,Exercise, Acute,Exercises,Exercises, Acute,Exercises, Aerobic,Exercises, Isometric,Exercises, Physical,Isometric Exercises,Physical Activities,Physical Exercise,Physical Exercises,Training, Exercise,Trainings, Exercise
D055815	Young Adult	A person between 19 and 24 years of age.	Adult, Young,Adults, Young,Young Adults
D018482	Muscle, Skeletal	A subtype of striated muscle, attached by TENDONS to the SKELETON. Skeletal muscles are innervated and their movement can be consciously controlled. They are also called voluntary muscles.	Anterior Tibial Muscle,Gastrocnemius Muscle,Muscle, Voluntary,Plantaris Muscle,Skeletal Muscle,Soleus Muscle,Muscle, Anterior Tibial,Muscle, Gastrocnemius,Muscle, Plantaris,Muscle, Soleus,Muscles, Skeletal,Muscles, Voluntary,Skeletal Muscles,Tibial Muscle, Anterior,Voluntary Muscle,Voluntary Muscles
D018737	Hand Strength	Force exerted when gripping or grasping.	Grasp,Grip,Grip Strength,Hand Grip Strength,Grasps,Grip Strength, Hand,Grips,Strength, Grip,Strength, Hand,Strength, Hand Grip