Flexibility for Intensity Dosing in Lingual Resistance Exercises: A Large Randomized Clinical Trial in Typically Aging Adults as Proof of Principle

Abstract

Objective: The objective of this study was to determine the effect of intensity dosing during tongue exercise on tongue pressure generation, adherence, and perceived effort. Design: This was a five-site, prospective, randomized clinical trial. Outcome measures were obtained across multiple baselines, biweekly during exercise, and 4-weeks post-intervention. Setting: The general community at each study site. Participants: Typically aging adults between 55–82 years of age with no history of neurological or swallowing disorders. Eighty-four volunteers completed the study. Interventions: Participants were randomly assigned to one of four exercise groups: (a) maximum intensity/no biofeedback, (b) progressive intensity/no bio-feedback, (c) maximum intensity/biofeedback, and (d) progressive intensity/ biofeedback. Half of the participants completed a maintenance exercise program. Outcome Measures: Maximum isometric pressure (MIP), regular effort saliva swallow pressure, adherence, and the Borg Rating of Perceived Exertion Scale. Results: All exercise protocols were efficacious for gains in MIP (large effect sizes; Cohen’s d). Group 3 made gains in regular effort saliva swallow pressure (medium effect size). There was a significant change in perceived exertion for regular effort saliva swallow pressure at 8 weeks. Tongue pressure gains were maintained at 1 month, regardless of maintenance group status. Mean adher-ence across groups was high. Conclusions: All groups improved pressure generation. Intensity dosing differ-ences did not affect strength gains, adherence, or detraining. Regular effort saliva swallow pressure may be most responsive to maximum intensity with bio-feedback. The findings suggest flexibility in approach to tongue exercise proto-cols. Tongue muscles may differ from limb muscles in terms of dose response and neuroplasticity principles.