Effect of tongue exercise on protrusive force and muscle fiber area in aging rats.
OBJECTIVE
Age-related changes in tongue function may contribute to dysphagia in elderly people. The authors' purpose was to investigate whether aged rats that have undergone tongue exercise would manifest increased protrusive tongue forces and increased genioglossus (GG) muscle fiber cross-sectional areas.


METHODS
Forty-eight young adult, middle-aged, and old Fischer 344/Brown Norway rats received 8 weeks of tongue exercise. Protrusive tongue forces were measured before and after exercise. GG muscle fiber cross-sectional area was measured in exercised rats and was compared with cross-sectional areas in a no-exercise control group.


RESULTS
A significant increase in maximum tongue force was found following exercise in all age groups. In addition, a trend for increased GG muscle fiber cross-sectional area and a significant increase in variability of GG muscle fiber cross-sectional area was identified postexercise.


CONCLUSIONS
The findings of this study have implications for treatment of elderly persons with dysphagia using tongue exercise programs. Specifically, increases in tongue force that occur following 8 weeks of progressive resistance tongue exercise may be accompanied by alterations in tongue muscle fiber morphology. These changes may provide greater strength and endurance for goal-oriented actions associated with the oropharyngeal swallow and should be investigated in future research.
Connor
Nadine P
NP
University of Wisconsin Clinical Science Center, Room K4/711, 600 Highland Avenue, Madison, WI 53792-7375, USA. connor@surgery.wisc.edu
Russell
John A
JA
Wang
Hao
H
Jackson
Michelle A
MA
Mann
Laura
L
Kluender
Keith
K
D000375:Aging; D000704:Analysis of Variance; D000818:Animals; D008297:Male; D018485:Muscle Fibers, Skeletal / Q000166:cytology*; D053580:Muscle Strength; D010805:Physical Conditioning, Animal; D051381:Rats; D011916:Rats, Inbred F344; D014059:Tongue / Q000166:cytology / Q000502:physiology*