Robert and Stuart (Last Updated On: July 9, 2009) Robert and Stuart perform a side leaning tricep extension on a stability ball during an STS rehearsal. Leaning on the stability ball causes the working arm to naturally stay in the correct vertical position. Post navigation Meet DensieCore Pushup Leave a Reply Cancel replyYour email address will not be published. Required fields are marked *Comment Name * Email * Save my name, email, and website in this browser for the next time I comment. This site uses Akismet to reduce spam. Learn how your comment data is processed.