The Leukemia & Lymphoma Society's Team In Training program (abbreviated "TNT") began back in 1988. Bruce Cleland formed a team that raised funds to run the New York City Marathon in honor of Cleland's daughter Georgia, a leukemia survivor. The team of 38 runners raised $322,000 for LLS's Westchester/Hudson Valley chapter. Team In Training has since grown into the world's largest endurance sports training program. Cleland was honored by Runner's World magazine in 2004 as one of their "Heroes of Running" for his role in establishing TNT.

Over the past 20 years, more than 380,000 participants have trained with the TNT team to compete in marathons, half marathons, triathlons, 100-mile century bike rides, and hiking adventures. The program offers hands-on training with certified coaches, weekly group runs, team training and social events, and mentors for fundraising support.

The Team In Training Gel-Ready Race Number Belt is an especially popular accessory for TNT participants or marathon runners. It can be used as a running belt or a triathlon belt which features lace locks to easily attach a race number, as well as ten elastic loops to keep gel packets handy. In keeping with their mission, Team In Training donates 10 percent of all sales to the Leukemia & Lymphoma Society's cancer research fund.