Jen Widerstrom is coach of The Oxygen Challenge 4 alongside Karina Smirnoff.Those who remember the remix of American Gladiators might recognize Jen as the pink-haired Phoenix, but these days, she is more widely known for her role as personal trainer on NBC’s hit series The Biggest Loser. Before she inspired millions to get moving, Widerstrom was a Division I hammer thrower at the University of Kansas. After completing her degree in sports administration, she became certified by the National Academy of Sports Medicine with an emphasis in nutrition, balance training, cardio performance, resistance training and neuromuscular stretching. She is also a certified fitness nutrition specialist and a CrossFit level-1 trainer.Beyond the gym, Widerstrom is dedicated to helping others through philanthropic endeavors, and she supports causes such as the Movember Foundation and the Breast Cancer Research Foundation. Widerstrom volunteers at orphanages and schools throughout Rwanda, Kenya and Malawi, helping children find self-confidence through sports and play, and she has gone on several goodwill military tours overseas to help raise morale. Widerstrom has appeared on numerous shows such as Dr. Oz, Live With Kelly and Ryan, The Talk, Today and Larry King Now. She has also appeared on the cover of Oxygen twice, and her book Diet Right for Your Personality Type (Penguin Random House, 2017) quickly became a best-seller and is now available in paperback.