Here is an interesting study published in Pediatric Physical Therapy. One hundred seventy six children in the child welfare system underwent gross motor skill evaluations, physical examinations and case workers were interviewed. The results indicated the following
significantly lower gross motor skills for children in foster care versus kinship care
children who were abused or neglected also received lower gross motor scores
overall the mean gross motor score for children in the child welfare system was lower that children in the general population.
Reference: Hanson. H. et al. Factors Influencing Gross Motor Development in Young Children in an Urban Child Welfare System Pediatric Physical TherapyWinter 2011 - Volume 23 - Issue 4 - p 335–346 doi: 10.1097/PEP.0b013e3182351fb5