50mm f/1.8 and 85mm f/1.8 lenses focus reasonably fast, and are pretty useful for indoor court sports like volleyball. Outdoor sports are pretty varied; high scholl football is pretty easy to shoot if it's played under daylight conditions, as many Junior Varsity gamers are played. At night, under the lights, the most critical camera setting is probably your ISO level--crank it UP!!! TO 1600 or 3200, most of the time. If all you have is a 50mm lens, that'll allow you to shoot pass plays and short rushing scores from the back line of the end-zone...a 50mm is fine for that,in fact.
Soccer is tricky...the ball moves up and down and across the field faster than in probably any other sport...but you can get shots on the goal from the end line with even a 50mm lens....but you have to be down there and standing there, ready. Be in the right spot for the lens you have!!!
I dunno...there's a huge, huge emphasis on ultra-telephoto sports photos among the higher-level practitioners of the modern era, and a love for the 300/2.8 and 400/2.8, but many people prefer sports shots with a little bit more context, and literally more "background" behind the athletes...especially for things like yearbook photos and local newspaper shots. Some very famous, and powerful sports shots have been made with shorter lenses, like Roger Bannister's famous 4-minute mile shot, where he passes the pack and they all look winded and stupefied...that was shot from like 10 feet away with a 28mm wide-angle...or Gary Winogrand's famous NFL shot of the Dallas Cowboys, probably done with a Leitz 24mm and his Leica M3, in which all 22 players are in the frame!!
On a crop-body, a 50mm is a 75mm FOV equivalent, and it's FAST....f/1.8...jack the ISO up and work what you got...positioning is more important that the gear, it really is. When a receiver catches a pass in the coffin corner and you're standing near the goal-posts on the end line, your 50mm is going to record the catch AND some of the stadium crowd behind it, and maybe the rally squad jumping up and down...a perfect shot for a yearbook or school newspaper type of photo.