On this episode of The Project Endure Podcast, Joe Rinaldi sits down with Sim Williams — endurance athlete, former boxer, Army veteran, husband, and father — for a deeply reflective conversation about loss, legacy, and the quiet strength required to keep going when life gets hard. Sim opens up about the personal losses that shaped his recent endurance pursuits, including his grandmother's battle with colon cancer and the sudden passing of his dog, Maverick, and how those experiences fueled his motivation during the 24 Hours of Stairs challenge. He shares how grief, responsibility, and love for his family helped him access a deeper level of mental resilience. Joe and Sim explore the lasting impact of mentors, with Sim reflecting on his grandmother's influence on his early fitness habits, faith, and values, and the idea that people live on through the way they shape us. The conversation also dives into identity, feeling like an imposter, and authenticity in a saturated fitness world, as well as the hardest decision Sim made on purpose—walking away from competitive boxing—and how that choice led him through military service, marriage, and eventually endurance running. From marriage and partnership to mental toughness and perseverance, this episode is an honest reminder that endurance is built not just through physical effort, but through purpose, connection, and the willingness to keep showing up. Give this episode a listen as we dive deep into Sim's life and learn about what persistence, perspective and endurance mean to him.

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