Geometrically accurate biological flow simulation: applications to pine cone pollination and graptolite hydrodynamics

Abstract

Objective: Restoration of stand-up motion in patients with complete paraplegia utilizing multichannel functional electrical stimulation, and analysis of the restored motion. Design: Nonrandomized control trial. Setting: General community, a referral center, institutional practice, and ambulatory care. Patients: Twelve volunteer samples were used for the collection of normal data. Two complete paraplegics received treatment for the restoration of stand-up motion. Main Outcome Measures: The electromyogram, joint angle, and floor reaction force were investigated during standing-up with arms crossed in front of the chest, and hands-assisted standing-up using parallel bars. The maximum knee joint torque during standing-up without hands-assists was calculated using a three-segment link model. Standing-up motion in complete paraplegics was restored, and then analyzed using the three-dimensional floor reaction force and the hip, knee, and ankle angles. Results: Main muscles used to stand up were the quadriceps, tibialis anterior, and paraspinal muscles. Hands-assists reduced the muscle activity and the vertical floor reaction force. Peak muscle activity was less during hands-assisted standing-up, except for the rectus femoris and the iliopsoas muscle. The maximum knee joint torque during standing-up was 1.6Nm/kg for both knees. Two complete paraplegics were able to stand up smoothly from a wheelchair based on stimulation data obtained from normal subjects. The characteristic pattern during standing-up was knee flexion preceding extension. Conclusion: Stand-up motion was restored utilizing electromyogram data and knee joint torque data from normal subjects.