A full length composite plate to be used as part of an outsole assembly in an article of footwear is disclosed. The full length composite plate comprises a composite material that has a certain percent elongation. The full length composite plate can include a heel cup for heel stability and improved traction. The full length composite plate also can include two angled portions along an arch region that provide arch support, as well as two flattened edges along the arch region to minimize or eliminate buckling. The forefoot region can be relatively flatter than the arch and heel regions, and notches are preferably included along a portion of the forefoot to increase flexibility.