Google has added mobile readiness to their list of criteria for ranking websites for their search results. This means that mobile friendly sites will get better placement than equivalent sites that are just designed for desktops.
Fortunately, RunSignUp was the first race registration site that was built mobile-ready. So your race pages should only see improvements in search results.
You can test your website here – https://www.google.com/webmasters/tools/mobile-friendly/.