Sports heroes - and news about news

''Records should be the servants not the masters of our body,'' says Sir Roger Bannister, the first runner to break the psychological barrier of the four-minute mile.

The story of this man's feat, the aftermath of his accomplishment, and his present circumstances are all investigated in a championship series of sports documentaries (''Numero Uno,'' PBS, Thursdays starting April 15 for 13 weeks, check local listings).

The Roger Bannister episode is the fourth in the 13-week series. It airs on May 6 and its emphasis on morality, its fine original footage, its clever editing, and Numero Uno cinematography will have you comparing it to the recent Academy Award winner ''Chariots of Fire.''

The initial episode in the series is the story of Japan's Taiho, a modern-day Sumo wrestling legend. The film not only gives you a sensitive picture of the man himself, but also a fascinating history of this centuries-old sport through antique Sumo prints.

Also included in the series are Australian swimmer Murray Rose; West German soccer-playing Bayern Munich; Belgian cyclist Eddy Merckx; Polish sprinter Irena Szewinska; Italian diver Klaus Dibiasi; Barbados cricketeer Gary Sobers; French skier Jean-Claude Killy; Argentine car racer Juan Maanuel Fangio; New Zealand runner Peter Snell; US discus thrower Al Oerter; and Finnish cross-country skier Veikko Hakulinen.

Written, produced, and directed by Bud and Cappy Greenspan, also responsible for ''The Olympiad,'' this series should score home runs and touchdowns with active sportsmen, armchair sportsmen, and total non-sportsmen alike. It is a clear and simple call - fine informative entertainment. Expanded news

Television news is making news itself these days.

In the midst of the three commercial networks' announcements of expanded news coverage in the late night, CBS has just revealed that its affiliates advisory board has agreed to ''defer further consideration of plans to expand the CBS Evening News.''

Thus, the longstanding dream of a one-hour evening news is definitely out for CBS, leaving NBC and ABC to carry the ball. Both networks, however, have found great affiliate resistance to network utilization of the commercially profitable 7:30-8 p.m. prime-time access half hour.

As a matter of fact, there is also some doubt as to the potential popularity of an expanded evening news with the viewers. A Roper poll just completed by Group W revealed that by a 2-to-1 margin viewers polled preferred a half-hour evening news to a one-hour program.

Meantime, however, all three networks are pushing ahead with plans for expansion of news coverage in other time periods. Insiders speculate that the spectacular growth of the 24-hour Cable News Network, together with CNN2 and the two Satellite News channels, are convincing executives that the public has an almost insatiable appetite for news - at the proper time. In addition, the considerable public curiosity about events in Poland, El Salvador, and now the Falkland Islands is tending to increase viewer interest in news still further. The success of ABC's ''Nightline'' during the Iranian crisis has made all the networks aware of the moneymaking, audience-getting potential of a hot news show.

Latest developments:

* On July 5, NBC will start airing a 1:30- 2:20 a.m. hard-news show, ''NBC News Overnight,'' Monday through Thursday and from 2-3 a.m. Saturdays (Sunday morning, that is).

* In September, from 2-5 a.m. daily, CBS will air ''Overnight.''

* In October ABC will air from midnight to 1 a.m. Tuesday through Friday a news-information show which, it is reported, will include Phil Donahue interviews. The show will follow ''Nightline.''

* In September ABC will introduce an early morning news show from 6-7 a.m. every weekday.

So, the pattern seems to be taking shape - national evening news will probably remain at a half-hour, but additional news shows in early morning and late night (or very early morning and early morning, if you will) will continue to proliferate.