Types of Stress Urinary Incontinence

Hypermobility, (“Hyper” means too much and “mobility” refers to movement) can result from childbirth, previous pelvic surgery or hormonal changes. Hypermobility occurs when the normal pelvic floor muscles can no longer provide the necessary support to the urethra. This may lead to the urethra dropping when any downward pressure is applied, resulting in involuntary leakage.
Normal functioning anatomy
A weakening of the muscles supporting the urethra causes the urethra to drop during physical activity, resulting in urine leaking. 
Intrinsic sphincter deficiency, or ISD refers to the weakening of the urethral sphincter muscles or closing mechanism. As a result, the sphincter does not function normally regardless of the position of the bladder neck or urethra.