Page 41 - Maximizing the efficacy of ankle foot orthoses in children with cerebral palsy

Joint kinematics will be assessed in the laboratory, using a three-dimensional mo- tion analysis system (OptoTrak, Northern Digital, Waterloo, Canada), while the subject walks on a 10m walkway at a self-preferred comfortable speed. Marker clusters will be attached to the feet, shanks, thighs, pelvis and trunk. To determine anatomical coordi- nate systems, anatomical landmarks will be palpated according to Cappozzo et al.[51]. Joint kinetics will be calculated by assessment of the ground reaction force, using an integrated force plate (OR6-5-1000, AMTI, Watertown, USA).
At baseline, all subjects will be measured walking bare foot and with shoes-only. An additional condition (old AFO-footwear combination) will be included for children who have (suitable) old orthoses. Follow-up recordings will be made while walking with the new FRO-footwear combination. Six trials, with the subject stepping on the force plate, will be completed for each condition (i.e. three trials for each leg). Data on joint kine- matics, and kinetics around the hip, knee and ankle will be averaged. Spatio-temporal parameters, such as step length [m], step width [m] and cadence [steps·min-1] will also be calculated.
Effect modifiers
As potential effect modifiers, the following outcome measures will be assessed: de- mographic variables, disease characteristics, personal and family characteristics, level of functional mobility and physical fitness (explained below).
Physical fitness
Physical fitness will be measured by means of an aerobic and anaerobic exercise test on a bicycle ergometer. The aerobic test will be performed according to the protocol described by Balemans et al.[52] and aerobic fitness will be defined as oxygen uptake over the 30 seconds with the highest sustained load (VO2peak) [ml·kg·min-1]. Anaerobic power will be determined using the 20 seconds Wingate Anaerobic cycling Test (20s-WAnT), a sprint test against a constant breaking torque[53]. Anaerobic fitness will be defined by the mean anaerobic power over 20 seconds (P20mean) [W·kg-1] and by the highest power output within the 20 seconds, the peak anaerobic power (P20peak) [W·kg-1]. Measurement
procedures, equipment and protocols for both tests will be as described by Balemans et al.[52].
II
The AFO-CP protocol
Gait biomechanics
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