The thought that lingers through this fast break toward a shot clock in college basketball is: why turn it off at all?

The Atlantic Coast Conference will have a 30-second clock, except for the last four minutes of regulation and the last four minutes of any overtime; the Big East and Southwest will have a 45-second clock, except for the final five minutes of regulation and all of overtime. The Sun Belt clock clicks off the last four minutes of regulation.

All these experiments are well-intended. But will they totally accomplish what most players and fans want? I doubt it, for after all the recent shot-clock tinkering very little has changed. Most of college basketball still will be two games in one 40-minute time frame: about 35 minutes of action and about five minutes of keepaway.

Game-long stallball, sustained drowsiness such as Maryland and North Carolina State subjected us to in the ACC tournament last year, has been eliminated. Hooray! But Dean Smith still will run his four-corners delay, as he always has. And for about as long.

That's not the problem. My concern is that the less-inventive coaches who have intruded on the game in the last several years, who have screeched the action to a halt, as a jockey would a thoroughbred at the eighth pole, still can. In the proper hands, keepaway is valuable and interesting strategy. But too many coaches misuse it, grasp it not as a way to score in a clever manner but to transfer pressure from themselves to the players.

On balance, however, the variety of new shot-clock rules are useful. They offer evidence, good and bad, for the NCAA to consider before national legislation is adopted. Independents and such conferences as the Big Ten still play the old-fashioned way, with no shot clock. And Southeastern Conference teams, bless 'em, will be under a 45-second clock the entire game this season.

International rules have included a game-long 30-second clock for years. There will be a three-point play, from a distance as yet undetermined, after the '84 Olympics in Los Angeles.

Until J. Dallas Shirley argued otherwise, with his usual thorough documentation and force, I thought the ACC's 19-foot range for three points was too short. Nineteen feet? Some of us fairly fat and 40 can hit from 19 feet, so isn't that giving too much of a reward for too common a skill?

Shirley says no, and he only helped devise and fine-tune most of the rules basketball has known.

The Southern Conference has used 22 feet as the boundary for its three-point play the last two years and found it too far, Shirley said. Very likely, it very soon will move the limit to just inside 20 feet.

Southern Conference teams made only 31 per cent of their shots from beyond 22 feet. With such a percentage in mind, defenses could sag nearly as much as they now do--and defeat the intent of the three-point legislation.

Probably, it's just coincidence. But the last two times there has been labor unrest in the National Football League another league has sprouted. The late, unlamented World Football League kicked off in '74 about the time NFL players were walking out of training camps.

With the possibility of a strike or lockout and the near certainty of some player-owner bitterness beyond repair, the United States Football League is starting to blossom. Players should rejoice, for it gives them more leverage against management, another option besides Canada and less lucrative manual labor.

Some of the USFL's proposals are appealing. Territorial rights, where a team can sign any collegian in a certain area of the country, is not among them. That offers the chance for the pros to influence where a player attends school. College recruiting is dirty enough already.

Won't someone in the USFL pretty please give George Allen a team? He's too good to keep on the sidelines forever. A Washington matchup against the Redskins would be the best idea since crab-flavored potato chips.

Mitch Kupchak will learn soon, perhaps this week, whether additional surgery on his injured knee is needed. That Dec. 16 fall was about as serious as possible, with a broken bone and cartilage and ligament damage. If surgery is necessary, it will be a Tommy John-like technique, borrowing a ligament from another part of his body to repair the knee.

"No season ever ends the same," he said in Philadelphia Sunday after watching his Lakers lose Game 2 of the NBA championship series to the 76ers. "I go out and bust myself up, and somebody puts me back together again."

He was referring to two back operations, one of them while an undergraduate at North Carolina, and the knee mess that leaves his career in doubt.

Smiling, Kupchak considered himself lucky to have been on teams that made the NBA's final series three of his five pro years. His second season, '77-'78, the Bullets won the championship; his third season, he was limited to the point where a June back operation was necessary and the Bullets finished second to Seattle.