Assessing movement biomechanics is important for understanding healthy locomotion, injury or disease progression, and recovery. However, laboratory- or clinic-based studies fail to capture the ecological factors of real-world activity. Advancements in wearable sensors provide an opportunity to capture movement biomechanics in these settings. This study demonstrates the capacity of a wearable system to measure patellar and Achilles tendon kinetics via tensiometry as well as knee and ankle kinematics via inertial measurement units (IMUs) while walking across varied terrains, including level ground, sloped pavement, and stairs. The wearable system successfully captured time-varying tendon loading over the walking gait cycle. Both patellar and Achilles tendon loading showed distinct sensitivities to changes in slope and stairs. Importantly, these tendon loading patterns correspond well with prior measurements of knee extension and ankle plantarflexion moment profiles obtained via traditional motion analysis. This represents a significant advancement over studies that relied on traditional complex, immobile equipment to obtain comparable results. The portability of the wearable system may allow for objective assessments of human performance, injury risk, functional adaptation due to injury, and treatment response in real-world environments.