Thanks for your query.Based on the facts that you have posted it appears that you have incontinence
of urine from childhood.and you had a habit of doing some exercise to control the same.
You are worried about damage to your sphincter.However this is theoretically impossible to damage sphincter.
You have to undergo some radiological tests like I.V.P. to rule out any congenital abnormality in urinary system
You can try to get financial help from some charity organisations to get investigation done .