Urinary incontinence (UI) makes a decline in the quality of life. A previous study showed that the pelvic floor muscles (PFM) exercise has been validated for the prevention of UI. These exercises, on the other hand, involve problems such as difficulty for the individual to realize the PFM contraction. For these reasons, the exercise is generally conducted with feedback such as visual feedback (FB). In our previous studies, the possibility of a new PFM exercise method using local vibration stimulation (VB) was examined, and it was confirmed that higher effects were obtained with the combined use of vibration stimulation compared to regular exercise. However, the difference in effectiveness between the VB method and the visual feedback (FB) method is unknown. In this study, we examined the effects of VB and FB method, as well as the effects of a combination of the two methods. Our hypothesis was that both exercise with VB and with FB would increase the effect of exercise over only PFM contraction exercise, although no difference between the two exercises. In addition, the combination of the two would produce a higher exercise effect.

This study was laboratory based cross sectional study. Ten healthy men participated in this study (Age; 23.7 ± 0.9 y.o., Height; 171.8 ± 5.9 cm, Body weight; 63.1 ± 7.1 kg, Body Mass Index; 21.4 ± 2.0 kg/ m2 [mean ± SD]). Each participant performed four conditions; only exercise (control), exercise with VB (VB), exercise with FB (FB), and exercise with VB and FB (combination). The measurement item was maximum voluntary contraction (MVC) of the PFM, which we measured using surface electromyography under the pre- and post-exercise. The participants performed 6 sets of 10-second contraction of the PFM as an exercise task. The exercises were performed in the sitting position on the original cushion with VB function and FB function using pressure sensor. The MVC was measured three times, and the average values were used for the analysis. Post-exercise PFM activities were normalized to pre-exercise status under each condition. Data analyses were performed using SPSS Statistics for Windows version 27.0 (IBM Japan Co. Ltd., Tokyo, Japan). The collected data was presented as median (min-max). The differences among the condition were analyzed using Kruskal-Wallis test and the Bonferroni post hoc test. In addition, the effect size (r) and power were calculated using G*power 3.1.9.7 software (Heinrich-Heine-University Düsseldorf, version 3.1.9.4, Düsseldorf, Germany). The significant level was set at 0.05. The study protocol complied with the principles laid down in the Declaration of Helsinki and was approved by our University Committee on Ethics in Research (approval number: E-2005).

The ratio of muscle activity (post-exercise / pre-exercise) between four exercise condition were summarized in Figure 1. The value was 0.96 (0.65-1.31) for control, 1.15 (1.00-2.24) for VB, 1.36 (0.75-2.37) for FB, and 1.32 (1.12-2.49) for combination. Statistically significant differences were shown in control and combination, and moderate to large effect sizes were observed for VB, FB and combination compared to the control condition.

This is the first study to show the difference between the effects of exercise using VB and FB. Moreover, we examined the effects of exercise when VB and FB were combined. The main finding of this study was that both VB and FB might increase the effect of exercise when used in addition to exercise, but there is no significant difference in effect between the two. Further, the use of a combination of these feedbacks could enhance the effect of exercise even more. In fact, all participants in this study showed an increase in muscle activity after exercise when it was exercise with combination condition.
The ability to transfer, or generalize, practiced motor tasks has long been known to be better in individuals who received FB during exercise than in those who did not. In addition, it is known that VB in combination with skeletal muscle contraction enhances the exercise effect through a mechanism named tonic vibration reflex, and we have reported in a previous study that local VB may increase the exercise effect when applied to PFM exercises. The results of this study also suggest that the effects of exercise were found to be supportive of these effects. For clinical application, however, it is necessary to consider that the participants in this study were healthy males.

The results of this study show that using VB and FB in regular PFM exercise enhances the effectiveness of the exercise. Although the use of these two types of feedback could be effective on the own, it is possible that a combination of VB and FB could be used to achieve a higher exercise effect.

Makoto K, et al.: The Acute Effect of Pelvic Floor Muscle Exercise with Local Vibration, Rigakuryoho Kagaku 34(5): 581–585, 2019 (Japanese).
Burns PA, et al.: A comparison of effectiveness of biofeedback and pelvic muscle exercise treatment of stress incontinence in older community-dwelling women. J Gerontol, 1993, 48: M167-M174.
Cochrane DJ, et al.: Changes in joint angle, muscle-tendon complex length, muscle contractile tissue displacement, and modulation of EMG activity during acute whole-body vibration. Muscle Nerve, 2009, 40: 420- 429.

Continence 2S2 (2022) 100472
DOI: 10.1016/j.cont.2022.100472