The Fusion Ortix 2021 is the first shoe highlighted in the “Every Runner’s Rights” campaign. We believe every runner has unique feet. At Karhu, we don’t dictate how our shoes should fit. Using state-of-the-art 3D foot imaging machines, Karhu builds its shoes off real runners’ foot scans. In order to be the best fitting shoe for optimal comfort, the Fusion 2021 is created from millions of foot scans analyzed by the research and development team.

Comfort & Propulsion

The Fusion Ortix 2021 functions as a high cushion daily trainer with more forefoot protection, a shortened fulcrum, and the addition of a propulsion unit. The midsole combination of the fulcrum and propulsion unit gives the Fusion a plush and energetic ride with a fast transition. The Fusion 2021 is ideal for more neutral footed runners seeking a cushioned, durable ride while logging daily miles or when picking up the pace during higher intensity efforts.


In the spirit of “Every Runner’s Rights,” female runners have the right to their own fit. Women’s and men’s foot scans were compared and significant differences in data points were discovered. The two most notable differences in measurements were at the instep and forefoot volumes. By creating a gender-specific footwear last and adjusting the fit, Karhu proudly introduces a women’s running shoe construction called HeraFit.


In order to accomodate more foot shapes, the Fusion is now offered in HiVo (high volume) which provides extra room in the upper for toes to spread. After the successful introduction of HiVo on the Ikoni 2020, it’s now time for the Fusion to receive an additional fit option. The HiVo version is more than just a “wide” as it accounts for feet with higher insteps and greater instep girths, and it works for people who prefer more room in the forefoot.

KARHU meaning “bear” in Finnish, is a leading running brand, and has provided technical running and outdoor gear for 100 years. With an authentic heritage in athletics and a deep connection to the outdoors, KARHU follows the Finnish principles of design simplicity and running purity. KARHU shoes have been worn on the feet of the greatest Finnish runners, including Paavo Nurmi and five Boston Marathon champions.