I recently purchased a Profoto B1 system to use for action portraits since you can sync to shutter speeds of up to 1/8000 of a second on Canon. To practice with it my buddy and I went out to the local outdoor basketball court and started seeing what we could come up with. Luckily it was getting closer to sunset and therefore there was some beautiful light on the backboard and trees. The sun also provided a nice backlight when cross lit with the B1.
The ability to shoot at high shutter speeds is great for action portraits as you can perfectly freeze the action outdoors and do not have to worry the dreaded black bar showing up in your frame. In the shot above the B1 is to camera left and the sun to the right, with camera settings of f/4 and 1/2000 shutter speed. There is no modifier on the B1. The sun illuminates the backboard and the right side of the arm/ball. You can see a slight color difference on the arm as the sun looks to be warmer than the B1 since it is setting.
The B1 is also very powerful compared to a speedlight. In these photos the B1 is "equaling" the setting sun. In broad daylight it can allow you to drop the bright background by a few stops depending on the modifiers you have on and how close it is to your subject. In most of these photos the B1 is about 10-15 feet away.
The best part about the B1 is that is has no cords! You don't need to find an outlet, can easily move it around, and put it places you can put other strobes. I put it on top of my tripod for extra stability since it can get a little top heavy on a light stand with no sand bags. I can't wait to do some more action shots with the B1! Funny thing is though that my favorite image from the day actually doesn't even use the B1. I dropped the white balance a bit in post to get a nice blue to make this silhouette pop. I love the crescent light on the ball! Don't get too attached to making a picture a certain way because you can miss out!