Many women themselves or their friends describe loss of urine with coughing or sneezing on occasion, but it's usually only a problem with a bad cold or severe allergies. A recent Norwegian study has looked at how prevalent a problem this is. Incontinence was associated with heavier body weight, with poor ability to contract pelvic floor muscles and with previous gynecological operations excluding hysterectomy. There was no convincing case of spontaneous remission. From the study, the authors conclude that in women aged 50-74 years, about one in five will need treatment of some sort.
Urinary incontinence is a chronic condition with little tendency to go away without treatment.
A retrospective study of female olympians. The bottom line is that while some loss of urine with straining is prevalent in many women, even trained athletes, impact from sports probably does not contribute at all to causing stress incontinence in later life.