Clark is a member of the Brooks Inspire Daily (ID) program. Brooks I.D. stands for Inspire Daily. These two simple words guide the principles of the program. Brooks I.D. is made up of over 800 members who are active in their running communities and share a passion for the Brooks brand. They are runners who are winners in their own right: Winning their age divisions, accomplishing their personal goals, pushing their own limits, and, by extension, encouraging others to do the same. They are coaches, mentors, and leaders.

In 1976 Clark started running, for fitness, and ran his first race ever, the Mercer Island Half Marathon, in 1978.  Also in 1978 he completed his first marathon.  Now, he credits 25 finished marathons, some pretty some not, and completed his Five Marathons in Six Weeks last October.