The goal of this study is to evaluate the effectiveness of using a regular menstrual tampon or a Uresta pessary to reduce urine leakage associated with running-induced stress urinary incontinence (RI-SUI) in females aged 18 and older. Secondly, the study aims to assess whether either intervention mitigates transient changes in pelvic morphology that occur following a single running bout. Lastly, we aim to evaluate whether participants continue using either intervention during running over the 4-week period following their in-lab participation. The hypotheses are:

Hypothesis 1: Among females with RI-SUI, both a tampon and pessary used during a single running bout will reduce urinary leakage symptoms, with greater symptom reduction observed when using the pessary.

Hypothesis 2: Participants will report high satisfaction and perceived symptom improvement with both the tampon and pessary, with higher satisfaction and greater improvement reported for the pessary.

Hypothesis 3: Both the tampon and pessary will reduce pelvic floor strain incurred by the end of the run, as evidenced by less bladder neck descent, levator plate lengthening, and levator hiatus area increasing relative to that observed when no tampon or pessary is used.

Hypothesis 4: A greater proportion of participants will report continued use of the pessary compared to the tampon over the 4-week post-lab period, with higher frequency of use and fewer reported discontinuations.

We will perform within-subject comparisons against baseline values to determine the effect of each intervention on RI-SUI symptoms and pelvic organ support.

Participants will complete a baseline questionnaire to collect demographic information and assess incontinence severity. They will then attend three laboratory visits within a 10-day period. At each visit, bladder volume will be standardized to between 100 and 200mL, then the participant will undergo three-dimensional (3D) transperineal ultrasound imaging conducted in a standing position. Following imaging, participants will complete a treadmill protocol consisting of 25-minutes running at a moderately difficult pace (rated at 13 - 14 on the Borg Perceiver Rate of Exertion scale), followed by 5 minutes of running at a higher intensity pace. During the run, participants will be asked at 5 minute intervals whether they experienced any urine leakage and to report their perceived amount of leakage. The ultrasound image protocol will be repeated immediately after the run.

Participants will be allowed to keep the pessary and will be contacted 4-weeks after the final visit to evaluate whether or not they continued use of a tampon or the pessary, and, if so, we will ask them to report their satisfaction with the intervention(s) they used.

More than 30% of females experience urinary incontinence (UI) during exercise. For many women, urine leakage during exercise can become a barrier to staying active, leading them to modify their exercise routine or avoid triggering activities altogether. Beyond the physical inconvenience, urinary incontinence can affect self-esteem, social participation, and mental health. Helping women stay active without embarrassment or fear of leakage has both physical and psychological benefits.

The pelvic floor muscles (PFMs) and associated connective tissues play a critical role in continence control. These structures support the pelvic organs and help maintain their positioning such that the urethra is optimally compressed during increases in intra-abdominal pressure. Dysfunction of the PFMs and connective tissues will cause the bladder to descend during weight-bearing activities, and the urethra, no longer in its optimal position, may remain open - resulting in urine leakage. This form of UI, known as stress urinary incontinence (SUI), is commonly experienced as urine leakage during tasks such as coughing, laughing, and physical activity. High-impact movements like running, jumping, and inclined walking are known to increase the loads experienced by the pelvic floor, making SUI especially common during these types of activities.

Intravaginal products such as tampons and pessaries (reusable medical devices placed in the vagina) are recommended to help manage UI during everyday activities such as coughing and sneezing. However, their effectiveness during physical activities - such as running or brisk walking - remains unclear. This study aims to determine whether a standard menstrual tampon and/or a bladder support (Uresta) pessary can reduce urine leakage during running and/or brisk walking in active females. A secondary objective is to assess whether these devices mitigate the descent of the bladder that we have observed in females after running or brisk walking. Lastly, we aim to assess continued device use over a 4-week period following all laboratory visits.

By evaluating the effectiveness of accessible, non-invasive devices, this research may offer immediate, low-barrier strategies to help active women self-manage urinary incontinence - empowering them to maintain their physical activity routines and support their long-term health.

Inclusion Criteria:

• Age >18 years of age
• Participate in any exercise or sport modality involving running or brisk walking
• Experiences urine leakage during running or brisk walking
• Speak and read English or French

Exclusion Criteria:

• No urine leakage in the first laboratory assessment (baseline / no intervention)
• Currently pregnant or have been pregnant in the previous 6 months
• Had or have had cardiac, pulmonary, metabolic and/or neurological conditions
• History of incontinence surgery
• Hysterectomy
• Symptoms consistent with urgency incontinence only
• Experience pain with tampon use or during gynecologic examinations

Data will be shared to investigators who contact the researchers and request access.

Information will be available beginning 1 month after publication with no end date.

No data sharing agreement necessary. Data will be made available to researchers wishing to perform secondary analyses or include the data in systematic reviews or meta-analyses.