No abstract

In patients with central neurological disorders, gait is often limited by a reduced ability to push off with the ankle. To overcome this reduced ankle push-off, energy-storing, spring-like carbon-composite Ankle Foot Orthoses (AFO) can be prescribed. It is expected that the energy returned by the AFO in late stance will support ankle push-off, and reduce the energy cost of walking. In 10 patients with multiple sclerosis and stroke the energy cost of walking, 3D kinematics, joint power, and joint work were measured during gait, with and without the AFO. The mechanical characteristics of the AFO were measured separately, and used to calculate the contribution of the AFO to the ankle kinetics. We found a significant decrease of 9.8% in energy cost of walking when walking with the AFO. With the AFO, the range of motion of the ankle was reduced by 12.3°, and the net work around the ankle was reduced by 29%. The total net work in the affected leg remained unchanged. The AFO accounted for 60% of the positive ankle work, which reduced the total amount of work performed by the leg by 11.1% when walking with the AFO. The decrease in energy cost when walking with a spring-like energy-storing AFO in central neurological patients is not induced by an augmented net ankle push-off, but by the AFO partially taking over ankle work.

Our results suggest that patient energy cost might be reduced by the proper choice of Ankle Foot Orthosis stiffness.

The aim of this study was to assess the functional effects and mechanical contribution of Ankle Foot Orthoses (AFO) prescribed to overcome drop-foot gait. We hypothesized that poor functional effects of the AFO relate to insufficient mechanical contribution of the AFO during the swing phase, or unwanted constraining of the ankle during the stance phase. In seven patients with Stroke or Multiple Sclerosis, we determined changes in energy cost of walking resulting from wearing an AFO, as a measure of the functional effects. In addition, an instrumented gait analysis was performed, and the mechanical AFO properties were measured, to calculate the mechanical contribution of the AFO. The AFO was sufficiently stiff to effectively support the foot in swing, without hampering the ankle during stance. For the whole group, there was a significant improvement in walking speed and energy cost (12%). However, the AFO had no functional benefit in terms of a reduced energy cost of walking for three patients, who coherently demonstrated no pathological plantar flexion during swing without their AFO. We conclude that functional benefit from the AFO was only found when the mechanical AFO characteristics met the need to support the patients' mechanical deficiencies.

No abstract

No abstract

27Quantitative assessment of an athlete's individual wheelchair mobility performance is one prerequisite 28 needed to evaluate game performance, improve wheelchair settings and optimize training routines. 29Inertial Measurement Unit (IMU) based methods can be used to perform such quantitative 30 assessment, providing a large number of kinematic data. The goal of this research was to reduce that 31 large amount of data to a set of key features best describing wheelchair mobility performance in 32 match play and present them in meaningful way for both scientists and athletes. To test the 33 discriminative power, wheelchair mobility characteristics of athletes with different performance levels 34 were compared. 35The wheelchair kinematics of 29 (inter-)national level athletes were measured during a match using 36 three inertial sensors mounted on the wheelchair. Principal component analysis was used to reduce 37 22 kinematic outcomes to a set of six outcomes regarding linear and rotational movement; speed and 38 acceleration; average and best performance. In addition, it was explored whether groups of athletes 39 with known performance differences based on their impairment classification also differed with 40 respect to these key outcomes using univariate general linear models. For all six key outcomes 41 classification showed to be a significant factor (p<0.05). 42We composed a set of six key kinematic outcomes that accurately describe wheelchair mobility 43 performance in match play. The key kinematic outcomes were displayed in an easy to interpret way, 44 usable for athletes, coaches and scientist. This standardized representation enables comparison of 45 different wheelchair sports regarding wheelchair mobility, but also evaluation at the level of an 46 individual athlete. By this means, the tool could enhance further development of wheelchair sports in 47 general. 48

Ankle Foot Orthoses (AFOs) to promote walking ability are a common treatment in patients with neurological or muscular diseases. However, guidelines on the prescription of AFOs are currently based on a low level of evidence regarding their efficacy. Recent studies aiming to demonstrate the efficacy of wearing an AFO in respect to walking ability are not always conclusive. In this paper it is argued to recognize two levels of evidence related to the ICF levels. Activity level evidence expresses the gain in walking ability for the patient, while mechanical evidence expresses the correct functioning of the AFO. Used in combination for the purpose of evaluating the efficacy of orthotic treatment, a conjunct improvement at both levels reinforces the treatment algorithm that is used. Conversely, conflicting outcomes will challenge current treatment algorithms and the supposed working mechanism of the AFO. A treatment algorithm must use relevant information as an input, derived from measurements with a high precision. Its result will be a specific AFO that matches the patient's needs, specified by the mechanical characterization of the AFO footwear combination. It is concluded that research on the efficacy of AFOs should use parameters from two levels of evidence, to prove the efficacy of a treatment algorithm, i.e., how to prescribe a well-matched AFO.