Which motions are the usual ones that tear an acl? What motions should I avoid?

ACL tears. In competitive sports, twisting motions are the most common precipitators of an acl tear--cutting, changing direction, sudden stops against force. Playing soccer causes as many injuries of this type as football. Young women are particularly at risk since their estrogen hormones make the ligaments looser.
Hyper extension of - -a loaded knee is one situation, the other is getting clipped with a rotational injury (internal) to the knee. This can lead to the “ terrible triad” injury. Tears of the MCL, then the medial meniscus followed by an ACL tear.