I'm really not keen on the crop here. For me I would have liked to have seen a tighter crop around the main part of the bow.
White background is definately stock though.
The image has a cut out appearance and would have been much better with some type of definitive background. While the title suggests the subject, the image is more oriented towards the archer and glasses rather than the bow sight. It might have been better to take the image from the front of the bow and emphasize the bow sight using a DOF fade. As a fitness image, it doesn't quite work.
I wish the whole arrow were included in this shot, I think it feels a little decapitated. Cool idea for a shoot, though, fits the challenge really well.