When the -ing form of a verb is used as a noun it is called a gerund. Gerunds are commonly used as the name of activities such as hiking, skiing, or running. A gerund may be used as a subject , a direct object , an indirect object , an object of a preposition , a subject complement , or an appositive.
Swimming is a healthy activity.
He gave canoeing the credit for making summer camp fun. We were impressed by her singing . Jacob's strongest talent, writing , helped him win the scholarship. The possessive form of a noun or pronoun should be used before a gerund.