oooohhhh . . . interesting lighting, very effective
how are you doing these?
remote flash?
second shot looks obviously like there's a remote down bottom left on far side of track, possibly using the onboard flash (or a gun set low) as the near tree faces are lit but not enough power for the rider
but on the 1st shot . . . I'd guess the remote flash is mid height on the left but also one high vertically above (just slightly to right) too, plus onboard flash?
simple slave or fancy triggers?
tell us your secrets!
looks like some planning went into these shots