If you strafe, you move perpendicular to view direction. If you combine strafe and jumps (the idea is this: jump, change view direction to perpendicular to jump

If you strafe, you move perpendicular to view direction. If you combine strafe and jumps (the idea is this: jump, change view direction to perpendicular to jump direction and then strafe => jump+strafe => you'd move faster in the original direction).