17mm, ISO 100, 1/250, f4
During the course I've experimented with fill-in flash to freeze movement - like here as my athletic niece gets some air, or someone tries a bit of slam-dunking. The flash has been adjusted in both cases to balance the exposure for a back-lit subject.
This is similar to exposures that I worked on at Fielden (here a still life shot and a portrait of Faiz) that required the same effect with fill-in flash.
We also adjusted our camera settings so that the fill in flash fired at different times during the raising and lowering of the shutter curtain. Above, with the first shutter curtain - the flash freezes the action at the start of a longer exposure, and so the light trail appears afterwards.
This image is with the flash timed to fire with the second shutter curtain - in other words at the end of the exposure. Now the light trail is recorded before the action is frozen and so appears to trail behind - an effect that seems more logical and natural.
Just before the course I experimented with a Speedlite flash gun mounted on the camera's hot shoe.