R. Lucia Riddle is the Owner of Sister Strength, LLC, a fitness company devoted to the wellness, cardio/strength training and physical conditioning needs of women 50 years of age and older. Riddle is a National Academy of Sports Medicine (NASM) Certified Personal Trainer (CPT) and holds NASM’s Weight Loss Specialist (WLS) certification.

Until March 31, 2012 she served as vice president – federal government relations with the Principal Financial Group ®.  In that capacity she directed the federal legislative and regulatory strategy for issues affecting the company, ranging from health care to tax policy to financial services. In addition, she served on the company's Law Department Management Committee and its Corporate Planning Group. Riddle holds an MBA from Drake University, is a Fellow of the Life Management Institute {FLMI}, and holds designations from America’s Health Insurance Plans and the International Claims Association.

Riddle serves on the Board of Directors of Pruve Systems, Inc. and is audit chair of TD&P Consulting Inc., both  privately held firms  based in Silver Spring, Md. In addition, she serves on the boards of Arena Stage, the National Caucus and Center on Black Aging, Inc. and Pathfinder International. She is an Emeritus Trustee of the Smithsonian National Museum of African Art, the Des Moines Art Center, and UnityPoint Des Moines Hospital System. She also is a member of the Executive Leadership Council, the Capital City Chapter of The Links, Inc.; Alpha Kappa Alpha Sorority, Inc.; and Sigma Iota Epsilon, an honorary business fraternity.

In 2008 and 2012, Riddle was named by Savoy Professional magazine as one of the "Top 100 Most Influential Blacks in Corporate America." The prestigious list showcases leaders with exemplary accomplishments, influence in their companies and communities and an ability to inspire others. In 2011, Riddle also received the President’s Award from the Washington Government Relations Group.  She is the 2022 recipient of the Washington Heads of Office Legacy Award.