{"id":288,"date":"2025-11-15T08:13:40","date_gmt":"2025-11-15T07:13:40","guid":{"rendered":"https:\/\/snaprace.app\/blog\/?p=288"},"modified":"2025-11-15T08:13:43","modified_gmt":"2025-11-15T07:13:43","slug":"caitriona-jennings-breaks-the-100-mile-world-record-in-2025-keys-to-ultramarathons-and-how-to-prepare","status":"publish","type":"post","link":"https:\/\/snaprace.app\/blog\/en\/caitriona-jennings-breaks-the-100-mile-world-record-in-2025-keys-to-ultramarathons-and-how-to-prepare\/","title":{"rendered":"Caitriona Jennings Breaks the 100-Mile World Record in 2025: Keys to Ultramarathons and How to Prepare"},"content":{"rendered":"\n

Modern running history is written with heroic feats. On the weekend of November 8, 2025<\/strong>, the ultradistance world witnessed one of those feats when Irish athlete Caitriona Jennings<\/strong> won the Tunnel Hill 100 Mile<\/strong> in Illinois with a time of 12 hours, 37 minutes and 4 seconds<\/strong>, pulverising the women\u2019s 100\u2011mile world record set by Camille Herron in 2017.<\/p>\n\n\n\n

Caitriona Jennings\u2019 100\u2011mile world record<\/h2>\n\n\n\n

Jennings, from Donegal, Ireland, and aged 45, arrived in Illinois with an impressive r\u00e9sum\u00e9: she holds the Irish national records for 50 km (3:16:33)<\/strong> and 100 km (7:43:01)<\/strong>, won the 2022 European 50 km title and has finished in the top ten of the demanding Comrades Marathon<\/strong> several times. She also ran the London 2012 marathon in 2:36. However, she had never tackled a 161 km race.<\/p>\n\n\n\n

The Tunnel Hill 100 Mile<\/strong> is run on a 50\u2011mile (80.5 km) course that runners complete twice. The route is a compact gravel trail on a disused railway and is renowned for its speed. The race is certified by USATF and the IAU; in fact, several world records have been set on this course. Jennings held an almost metronomic pace, averaging 7:34 min\/mile (4:42 min\/km)<\/strong> with minimal variation until kilometre 120, and finished fourth overall, nearly four hours ahead of the next woman.<\/p>\n\n\n\n

The silver medal on the day also went to a woman: American Anne Flower<\/strong> broke the 50\u2011mile world record<\/strong>, stopping the clock at 5:18:57<\/strong>. Flower, an emergency physician, has won races like Leadville 100, Silver Rush 50 and Javelina 100 K in the last two years. In the men\u2019s competition, Phil Young claimed victory in 12:03:27, followed by Reese Slobodianuk (12:05:38) and Rob King (12:16:09).<\/p>\n\n\n\n

Who is Caitriona Jennings<\/h3>\n\n\n\n

In addition to her national titles, Jennings is known for her ability to stay strong in the face of great challenges. This year she set the Irish 50 km record with 3:16:33<\/strong> and continues to hold the country\u2019s best 100 km mark. Her victory in Illinois not only confirms her versatility but shows that age is no barrier in ultrarunning: at 45, she has achieved a performance that until recently seemed unattainable.<\/p>\n\n\n\n

Why Tunnel Hill is the ideal course for records<\/h2>\n\n\n\n

The Tunnel Hill 100<\/strong> takes place on the Tunnel Hill State Trail<\/strong>, an unpaved track built on a former railway line. Its flat profile and compact gravel surface reduce impact and allow runners to maintain a steady rhythm. The route consists of a double out\u2011and\u2011back<\/strong> with a short passage through an old railway tunnel. It is sanctioned by USATF and the IAU<\/strong>, and some consider it both a road and a trail race because of its surface. This design, combined with well-organised aid stations, means many athletes go <\/p>\n\n\n\n

there in search of personal bests.<\/p>\n\n\n\n

Anne Flower\u2019s 50\u2011mile record and other marks<\/h2>\n\n\n\n

Anne Flower\u2019s<\/strong> performance at the Tunnel Hill 50 Mile<\/strong> deserves its own section: her time of 5:18:57<\/strong> improved the previous world best by more than twelve minutes. The American averaged around 3:58 min\/km<\/strong> and proved that speed also plays a role in extreme distances. This double women\u2019s record joins other historic achievements on the same circuit and reopens the debate about the limits of human endurance.<\/p>\n\n\n\n

How to prepare for an ultramarathon: training and nutrition strategies<\/h2>\n\n\n\n

Ultramarathons require more than thousands of kilometres: they demand careful planning of nutrition, hydration and physiological adaptation<\/strong>. The International Society of Sports Nutrition<\/strong> has an official position statement on nutrition in ultramarathons<\/a> that summarises the science\u2011based guidelines:<\/p>\n\n\n\n