Running with an exotendon reduces compressive knee contact force

Area of Science:

• Biomechanics
• Human Movement Science
• Sports Engineering

Background:

• Exotendons are designed to reduce the energetic cost of running by coupling the legs.
• The impact of exotendon use on joint contact forces, particularly in the lower extremities, remains largely uninvestigated.

Purpose of the Study:

• To determine if using an exotendon affects hip, knee, and ankle joint contact forces during running.
• To quantify changes in compressive and shear forces at these joints.

Main Methods:

• Muscle-driven simulations were employed using experimental data from seven participants.
• Simulations analyzed running at 2.7 m/s with and without an attached exotendon.
• Compressive and shear contact forces at the hip, knee, and ankle were computed.

Main Results:

• Running with an exotendon resulted in an 8.4% reduction in peak knee compressive contact force.
• This reduction was primarily attributed to decreased forces in the quadriceps muscles.
• No significant changes were observed in peak hip or ankle joint contact forces (compressive or shear).

Conclusions:

• The exotendon, while not designed for this purpose, can reduce peak knee compressive forces during running.
• The device alters gait mechanics to decrease both energetic cost and knee joint loading.
• Further research could explore optimizing exotendon design for joint force mitigation.