As the speed increases the legs converge toward the center line. The Belgian Sheepdog tends to single track.
Notice the position of the tail, it should be an extension of the top line. This photo shows nice flexibility in the front and read, nice extension without being hard driving.
Notice the tail position, this is also acceptable. The tail tends to rise as the they reach full speed and the excitement increases. It can be carried slightly above the top line.
The tail comes off the topline level then rises toward the end. This is typical, the standard wording states, “When in action he raises it and gives it a curl, which is strongest towards the tip, without forming a hook.”