1C70 Feasibility Study

Inclusion Criteria: * Person is at least 18 years old. * Person is a unilateral transtibial amputee with stabilized residual limb. * Person is a K3 ambulator based on Medicare Functional Classification Level (MFCL) . * Person has at least 6 months experience in walking with a prosthesis. * Person is using an energy storage and return (ESR) foot as their primary everyday foot * Person has a foot size between 22 and 30. * Person weights with a prosthesis between 50 and 125 kg (foot size 26 - 30), or between 45 and 100 kg (foot size 22 - 25). * Person wears a prosthesis daily and ≥ 8 hours/day. * Person is able to walk at least 500 m without having to make a break. * Person is willing and able to independently provide informed consent. * Person is willing to comply with study procedures. Exclusion Criteria: * Person is pregnant. * Person is using a hydraulic foot as their primary everyday foot. * Person is using a sport foot (e.g., Fillauer AllPro, Ottobock Challenger, Össur Flex-Foot Cheetah) as their primary everyday foot. * Person is using an ESR foot with an integrated vacuum pump (e.g., Ottobock 1C62 Triton Harmony). * Person has conditions that would prevent participation and pose increased risk (e.g., unstable cardiovascular conditions that preclude physical activity such as walking). * Person falls ≥ once a week due to the reasons that are not related to prosthesis (e.g., problems with vestibular system). * Person is not available for study visits during planned study…