Recently I took individual photos for my son’s high school swim team. Set up the photo shoot at the end of the evening’s team practice in an outdoor pool after sunset. I placed 2 off-camera flash strobes with radio triggers on light stands on opposite sides of the pool area, equal distant to the selected center swimming lane. I then had each swimmer swim the lane using the butterfly stroke or breast stroke.
The butterfly stroke provides the best visual of the swimmer as they swim straight at the camera, head coming straight up to breath and arms swinging up out of the water from the rear to the front.
The breast stroke provides a head forward perspective too but the arms are underwater providing no visual presence to the shot.