Swimmer breathing during front crawl. The front crawl or forward crawl is a swimming stroke usually regarded as the fastest of the four front primary strokes. As such, the front crawl stroke is nearly universally used during a freestyle swimming competition, hence freestyle is used metonymically for the front crawl.wimmer breathing during front crawl. The front crawl or forward crawl is a swimming stroke usually regarded as the fastest of the four front primary strokes. As such, the front crawl stroke is nearly universally used during a freestyle swimming competition, hence freestyle is used metonymically for the front crawl.