Hajime no Ippo is a sports anime based on the long running manga (861 chapters and counting). The story primarily follows Makunouchi Ippo and his rise through the Japanese pro boxing featherweight class. The series is very straightforward and lacking complexity or depth, but that is part of the reason the manga has been able to continue so long. You could honestly start the series at a random episode and probably enjoy it just as much as if you had started from the beginning.
What Hajime no Ippo has is excellent pacing. Largely the story alternates between fights and training, with a few break episodes tossed in. The pace is very steady, with very few climaxes and troughs.
The first series is 76 episodes long. If you're into sports or fighting series, Ippo might be worth a shot. There is also a second, 26 episode long, series and rumors of a third.