a partner can increase motivation, persistence, and therefore performance when the subject is paired with a superior workout partner, including if that partner is virtually present. While any type of grouping tends to improve exercise motivation, several studies show that conjunctive pairings lead to the greatest performance improvement. For example, time spent on a stationary bike is recorded based on the first partner to drop out, rather than having partners simply cycling beside each other (coactive). This has been shown with exercise games, aerobic activity, and competitive races. Differences in partner age and weight do not appear to influence the Kohler effect. References Collaboration