Final answer:
The Valsalva's maneuver involves voluntary contraction of the diaphragm and abdominal muscles to increase intra-abdominal pressure, facilitating bladder emptying.
Step-by-step explanation:
An individual may choose to empty the bladder prior to the initiation of the micturition reflex by contracting the abdominal muscles as part of the Valsalva's maneuver. This maneuver involves voluntary contraction of the diaphragm and abdominal wall muscles, along with closing of the glottis, to increase intra-abdominal pressure. By doing so, more forceful bladder emptying can be achieved.