PURPOSE: The aim of this study was to investigate the coordination among reaching kinematics, ground reaction forces and muscle activity in standing in children with severe spastic diplegia wearing dynamic ankle-foot orthoses (DAFOs)and compare the results to age matched non-disabled children. RELEVANCE: Assessment and evaluation are essential because children with spastic diplegia, classified at level III-IV according to GMFCS (Gross Motor Function Classification System), often recieve DAFOs as an adjunct to physiotherapy in order to improve sitting, standing and walking. PARTICIPANTS: All children with spastic diplegia using DAFOs in a county in northern Sweden and had regular follow-ups of their ortohoses, were invited. Six participants at GMFCS level III-IV formed the study group and six age- and sex-matched children with normal motor development served as a control group. METHODS: Bilaterally ground reaction forces and the ankle muscle activity aswell as the reach hand kinematics were investigated by the means of two AMTI forceplates, surface electromyography (EMG)and two-camera optoelectronic system (ELITE). Kinematic, EMG and forceplate signals were recorded simultaniously. The children reached for a cup filled with candy while standing on two forceplates. Reflective markers were placed on the hand and cup. In this study, standing support provided by the parent on the pelvis or by contact of the non-reach hand on the table was necessary during the standing task. ANALYSIS: Because of the small participant number and the heterogeneity of the group with pronounced difficulties in locomotion, the results are presented on group as well as on subject level. RESULTS: Children with severe spastic diplegia, wearing DAFOs, demonstrated that movement quality of upward and forward reach velocity differed regarding temporal phasing and amplitudes of velocity peaks compared to the controls. Furthermore, children with severe spastic diplegia, wearing DAFOs, lacked a coordinated muscle activity pattern and make use of postural adjustments characterized by co-activation of agonist and antagonist muscles. However, the controls demonstrated coordinated muscle activity and an interplay of the ground reaction forces on reach and non-reach side. CONCLUSIONS: In conclusion DAFOs appear to provide some benefit for children with spastic diplegia GMFCS, level III-IV, by the use of postural adjustments for balance control during a reaching movement in standing. An intervention study would be of interest, to assess whether DAFOs could be valuable in the learning of processes considering postural adjustments , since postural control is a result of both maturation and learning. IMPLICATIONS: Children with severe spastic diplegia wearing DAFOs can despite different support conditions practice reaching while standing and thereby promote motor learning of postural adjustments to improve the ability to use the hands in daily standing activities.