Effect of Rest Interval Length on Oral Swallowing Pressure During Effortful Swallowing Exercises in Healthy Adults: A Crossover Design.

Evidence supporting the prescription of effortful swallowing (ES) as a rehabilitation exercise remains lacking. This study aimed to evaluate the effect of rest interval length between sets on oral swallowing pressure during ES exercises in healthy adults. This study was a randomized trial of participants using a crossover design. Forty-three healthy adults (25.0 ± 3.7 years; 32 women and 11 men) without swallowing difficulties were recruited and participated in all four conditions (rest intervals between sets: 0-, 1-, 3-, and 5-min intervals) in a random order. The exercise constituted five sets, each comprising 10 ES repetitions. ES was performed with saliva swallows. The rest interval between each repetition was fixed at 10 s, and the oral swallowing pressure during ES was measured using a tongue pressure measuring device. Oral swallowing pressures were significantly lower in the fifth set than in the first set at the 0-min rest condition. In the comparison by condition, oral swallowing pressures were significantly higher in the 5-min than in the 0-min rest conditions in the fourth set and in the 3- and 5-min rest conditions than in the 0-min rest condition in the fifth set. A rest interval of appropriate length between sets during ES exercises may consistently maintain the targeted high swallowing pressures during the exercises. Further studies using more diverse equipment and targeting older patients and those with dysphagia are required to determine the effect of the rest interval length between sets on the degree of exercise intensity to improve the swallowing-related muscle strength.