You’re going to need to ask

You’re going to need to ask the coaches how they’re viewing the footage. Dropbox does have a player but the quality is low res. .MTS files can be viewed with Media Player, but you probably should combine the files in an NLE and render out an MP4. I shoot lacrosse games and before transferring the footage to the contractor, convert them into an MP4 at a relatively low bit rate, around 4 Mbps in Adobe Premiere Pro. That keeps the size of the files manageable.

You might want to take a look at Hudl, http://www.hudl.com/ an online coaches viewing platform.