High impact exercises, such as jumping, are strongly associated with high prevalence of urinary incontinence (UI) in women and young athletes.  This study has the objective of test the hypothesis that women with UI have lower activation of the pelvic floor muscles (MAP) when compared to women without UI in response to vertical jump

The cross-sectional study with a functional kinetic based on data from 35 adult women. The women were divided into two groups, with and without UI, according to the International Consultation on Incontinence Questionnaire - Short Form (ICIQ-SF). Surface Electromyography (EMG) acquisition of the MAP was obtained during the vertical jumping countermovement exercise at the time when the women touched the ground with their feet. For the analysis of the signals, the software Miotec Suite Version 1.0 was used and the fourth-order Butterworth analog filters (20 Hz High Pass Filter, 500 Hz Low Pass Filter) and 60 Hz Filter (nortch) slot for the extrinsic interference of the collection and its harmonics. Comparisons between volunteers with and without UI were made. The chi-square  test  was  used  to  evaluate  the  categorical  variables,  while  the  test-t  student  for independent samples or the Mann-Whitney U test was used to test the differences between  the means of the groups. The Student's t-test for paired samples or the Wilcoxon test was used to analyze the differences between group means at two different moments.

Thirty-five women selected by eligibility criteria were categorized into two groups: women without UI (n = 22) and women with UI (n = 13).  The descriptive statistics of the participants categorized in continence and urinary incontinence with general homogeneous characteristics, the median (IQR) of the participants' age was 27 (21-36) years, 37.1% were incontinent, 22.9% were sedentary and 36.4 % had high visceral fat.  The comparison of the EMG activity of the PFM in pre-activity through the analysis of the MVC, pre-jump, during the jump and post jump (Figure 1), between the groups with continence and without urinary incontinence. The difference between the maximum voluntary contraction (MVC) found in the continents was an average of 71.8 (± 29.8) and in the incontinent participants, 48.4 (± 34.1), p = 0.042. The normalized analysis of the PFM's EMG data of the continents  and incontinent women when analyzed in pre-activity and post-jump presented strong statistical differences (p <0.001) and (p = 0.0002) respectively. However, when comparing the data between the groups, no statistically significant differences were found (p> 0.05).

The hypothesis of this study was based on the assumption that in response to the impact caused by the vertical jump, women with urinary incontinence would present a lower activation of the PFM when compared to the continent women. However, we found an annulment of our hypothesis, that is, we demonstrated that the activation of these muscles was similar in the groups. According to our knowledge, this was the first study that analyzed the activation of PFM during the vertical jump between women with and without UI. The impact on the ground during physical activities has been associated with the loss of urine in female athletes. There is a biological plausibility that points to a direct relation of the urine loss due to the increase of the intra-abdominal pressure during physical activities; however, our study contradicts this theory, since we found the same values of muscle activation in both groups during the movement.

This study contributed to the knowledge about the activity of the PFM during the vertical jump while body movement translates impact. We observed that in spite of the high activation of the PFM that occurs in the pre-activity and the post-jump, when in comparison between the EMG behavior and the continents and incontinent groups, there are no differences. This may indicate that other mechanisms may be involved in urinary incontinence during impact activities. Future studies are needed to identify the participation of accessory muscles in vertical jump activity as they play an important role in maintaining continence during impact activities.

Moser H, Leitner M, Baeyens JP, Radlinger L. Pelvic floor muscle activity during impact activities in continent and incontinent women: a systematic review. International urogynecology journal. 2017
Luginbuehl H, Naeff R, Zahnd A, Baeyens JP, Kuhn A, Radlinger L. Pelvic floor muscle electromyography during different running speeds: an exploratory and reliability study. Archives of gynecology and obstetrics. 2016;293(1):117-24