Exploring ankle joint physiologic functional stiffness is crucial for improving the design of prosthetic feet that aim to mimic normal gait. We hypothesized that ankle joint stiffness would vary among the different activities of daily living and that the magnitude of the stiffness would indicate the degree of energy storage element sufficiency in terms of harvesting and returning energy. We examined sagittal plane ankle moment versus flexion angle curves from 12 healthy subjects during the daily activities. The slopes of these curves were assessed to find the calculated stiffness during the peak energy return and harvest phases. For the energy return and harvest phases, stiffness varied from 0.016 to 0.283 Nm/kg° and 0.025 and 0.858 Nm/kg°, respectively. The optimum stiffness during the energy return phase was 0.111 ± 0.117 Nm/kg° and during the energy harvest phase was 0.234 ± 0.327 Nm/kg°. Ankle joint stiffness varied significantly during the activities of daily living, indicating that an energy storage unit with a constant stiffness would not be sufficient in providing energy regenerative gait during all activities. The present study was directed toward the development of a complete data set to determine the torque-angle properties of the ankle joint to facilitate a better design process.
Level of Clinical Evidence
To read this article in full you will need to make a payment
Purchase one-time access:Academic & Personal: 24 hour online accessCorporate R&D Professionals: 24 hour online access
One-time access price info
- For academic or personal research use, select 'Academic and Personal'
- For corporate R&D use, select 'Corporate R&D Professionals'
Subscribe:Subscribe to The Journal of Foot and Ankle Surgery
Already a print subscriber? Claim online access
Already an online subscriber? Sign in
Register: Create an account
Institutional Access: Sign in to ScienceDirect
- Estimating the prevalence of limb loss in the United States: 2005 to 2050.Arch Phys Med Rehabil. 2005; 89: 422-429
- Available at)http://www.cdc.gov/nchs/Date accessed: March 19, 2014 (
- Revisiting transtibial amputation with the long posterior flap.Br J Surg. 2001; 88: 683-686
- Active functional stiffness of the knee joint during activities of daily living: a parameter for improved design of prosthetic limbs.Clin Biomech (Bristol, Avon). 2014; 29: 1193-1199
- Chronic low back pain in traumatic lower limb amputees.Clin Rehabil. 2005; 19: 81-86
- A comparison of traditional prosthetic training versus proprioceptive neuromuscular facilitation resistive gait training with transfemoral amputees.Prosthet Orthot Int. 2002; 26: 213-217
- Kinematic and kinetic comparisons of transfemoral amputee gait using C-Leg and Mauch SNS prosthetic knees.J Rehabil Res Dev. 2006; 43: 857-870
- Prototype design and realization of an innovative energy efficient transfemoral prosthesis.in: Proceedings of the 210 3rd IEEE RAS & EMBS International Conference on Biomedical Robotics and Biomechatronics. University of Tokyo, Tokyo, Japan2010
- Biomimetic-based smart rehabilitation technology: application of biomimetics in the design of medical devices.in: Bar-Cohen J. Biomimetics: Nature Based Innovation. CRC Press, Boca Raton, FL2012: 445-460
- The human ankle during walking: implications for design of biomimetic ankle prostheses.J Biomech. 2004; 37: 1467-1474
- Effects of window size on ankle joint stiffness calculation during quiet standing: how the rule changes the result.J Biomech. 2012; 45: 2301-2305
- The role of joint stiffness in quiet standing and gait initiation in healthy, young adults.in: The 3rd Asian Pacific Conference on Biomechanics, Tokyo, Japan. 2007
- Modeling effects of muscle fatigue on unilateral postural control.J Appl Biomech. 1996; 12: 173-184
- Analysis of mechanical and metabolic factors in the gait of congenital below knee amputees: a comparison of the SACH and Seattle feet.Am J Phys Med. 1992; 71: 272-278
- Energy expenditure during ambulation in dysvascular and traumatic below-knee amputees: a comparison of five prosthetic feet.J Rehabil Res Dev. 1995; 32: 111-119
- Prosthetic weight acceptance mechanics in transtibial amputees wearing the Single Axis, Seattle Lite, and Flex Foot.IEEE Trans Rehabil Eng. 1997; 5: 283-289
- Kinematic and kinetic variations of below-knee amputee gait.J Prosthet Orthot. 2002; 14: 2-10
- The condition for dynamic stability.J Biomech. 2005; 38: 1-8
- The major determinants in normal and pathological gait.J Bone Joint Surg Am. 1953; 35: 543-558
- The influence of walking speed on mechanical joint power during gait.Gait Posture. 1997; 6: 171-176
- Temporal, kinematic, and kinetic variables related to gait speed in subjects with hemiplegia: a regression approach.Phys Ther. 1994; 74: 872-885
- Energy generation and absorption at the ankle and knee during fast, natural and slow cadences.Clin Orthop Relat Res. 1983; 175: 147-154
Published online: March 30, 2018
Financial Disclosure: This study was funded by the Ohio Department of Development, State of Ohio (TECH 09-001), which provided funding in support of the Rapid Rehabilitation and Return to Function for Amputee Soldiers project.
Conflict of Interest: None reported.
© 2017 by the American College of Foot and Ankle Surgeons. All rights reserved.