There is a high prevalence of urinary incontinence (UI) among female athletes and exercisers, especially in sports including high impact activities and heavy weightlifting. CrossFit and functional fitness is a popular exercise form, including a combination of heavy lifting and high impact activities at high intensities. In several recent studies, high prevalence rates of UI have been reported among female CrossFit/functional fitness exercisers. UI is defined as "the complaint of involuntary loss of urine". Stress urinary incontinence (SUI) is the most common type of UI and is defined as "the complaint of involuntary loss of urine on effort or physical exertion (e.g. sporting activities), or or sneezing or coughing". Urinary leakage during sport activities may affect athletes' and exercisers' performance, cause bother, frustration and embarrassment and furthermore lead to avoidance and cessation of sport activities. Pelvic floor muscle (PFM) training is highly effective in treating SUI in the general female population. However, evidence of the effect of PFM training in exercisers participating in high impact and heavy weightlifting activities is sparse.

The purpose of this assessor-blinded randomized controlled trial (RCT) is to assess the effect of PFM training on symptoms, bother and amount of SUI in female CrossFit/functional fitness exercisers.

BACKGROUND:

Physical activity and exercise have well-known beneficial effects on several physical and psychological health outcomes. However, it has been proposed that regular participation in physical activity and exercise may lead to greater risk of developing pelvic floor dysfunctions (PFD) in women. The pelvic floor consists of muscles, fascia and ligaments and forms a hammock-like support at the base of the abdomino-pelvic cavity. The function of the pelvic floor is to provide support to the pelvic organs (the bladder, urethra, vagina, uterus and rectum) and to counteract all increases in intra-abdominal pressure and ground reactions forces during daily activities. Additionally, the pelvic floor facilitates intercourse, vaginal birth, storage of stool and urine and voluntary defecation and urination. A dysfunctional pelvic floor can lead to urinary and anal incontinence, pelvic organ prolapse, sexual problems and chronic pain syndromes. UI is the most common PFD, defined as "the complaint of involuntary loss of urine". SUI, urgency urinary incontinence (UUI) and mixed urinary incontinence (MUI) are common subtypes of UI. In women, SUI accounts for approximately half of all incontinence types and is defined as "the complaint of involuntary loss of urine on effort or physical exertion (e.g. sporting activities), or on sneezing or coughing". UUI is defined as the "complaint of involuntary loss of urine associated with urgency" and MUI as "complaints of both stress and urgency urinary incontinence".

High prevalence rates of UI among both parous and nulliparous female athletes and exercisers have been reported in several cross-sectional studies. The prevalence rates varies between 0-80% with the highest prevalence found in high impact sports such as trampoline jumping, gymnastics and strengths sports with high increases in intraabdominal pressure (e.g. powerlifting). CrossFit and functional fitness, which are trending exercise forms, includes a combination of heavy lifting and high impact activities at high intensities. High prevalence of UI among CrossFit/functional fitness exercisers has been reported in several recent cross-sectional studies, ranging from 41-84%. Leakage during sport and exercise may affect performance and cause bother, frustration and embarrassment, and may further lead to avoidance or cessation of sport and exercise.

To date, there is level 1 evidence and grade A recommendation for PFM training alone to be first line treatment for SUI, MUI and pelvic organ prolapse in the general female population. In addition, PFM training is highly effective as primary prevention; pregnant continent women who exercise the PFM are at 62% less risk of UI in late pregnancy and 29% less risk of UI 3-6 months postpartum. Evidence of the effect of PFM training in athletes or strenuous exercisers is sparse.

In one study on female soldiers and two small case series in female athletes and exercisers, PFM training led to reduced symptoms of UI. However, none of these studies included a non-treated control group and the internal validity is therefore low. To our knowledge, only one RCT has assessed effects of PFM training on SUI in athletes. Female volleyball players (n=16) who followed a PFM training program had significant improvements of SUI compared to a control group (n=16).

Based on today's knowledge we do not know whether PFM training is effective in strenuous exposed to excessive impact and increases in intraabdominal pressure during CrossFit- and functional fitness activities. Given the high impact on the pelvic floor in these exercisers, it is presumed that they need much better pelvic floor muscle function than non-exercisers. On the other hand, these exercisers may be motivated for regular training. Strength training of the PFM, if proven effective, may be easily incorporated in their basic training regimens both as prevention and treatment strategies of SUI.

AIMS:

The aim of this RCT is to assess the effect of PFM training on symptoms, bother and amount of SUI among female CrossFit and functional fitness exercisers.

STUDY DESIGN AND METHODS:

To recruit participants, we will contact CrossFit boxes and functional fitness clubs in or near Oslo. Social media platforms (such as Facebook, Instagram) will also be used. The study is an assessor-blinded RCT evaluating the effect of PFM training on SUI in CrossFit and functional fitness exercisers. At baseline, a pelvic floor muscle assessment (resting pressure, strength and endurance) will be performed of all participants. In addition, the participants will respond to an electronic questionnaire, measuring self-reported symptoms of UI and bother. The participants will be randomly assigned to either a PFM training group (EG) or a control group (CG) with no intervention. The intervention consists of a daily home-based PFM training program with weekly follow-up by a physiotherapist. After a 16-week intervention period, all participants will perform a post-test including the same previous mentioned outcome measures.

Inclusion Criteria:

• Age ≥18
• ≥ 6 months of consistent participation in CrossFit or functional fitness training
• Participating in ≥ 3 sessions of cross-fit training per week
• Self-reported SUI and a total score on ICIQ-UI-SF of ≥ 3. A change of the ICIQ-UI-SF score of 2.5 has been identified to be the minimal important difference (MID) and 1.58 as between-treatment MID (Nystrom et al., 2015).
• No musculoskeletal injuries for the past 6 months with negative effect on training participation

Exclusion Criteria:

• Ongoing pregnancy, or planning to get pregnant during the intervention period
• History of hysterectomy or pelvic surgery to correct UI or POP
• History of musculoskeletal injuries for the past 6 months with negative effect on training participation
• Parous women who are ≤12 months post-partum