John Cook says that when he was hired to coach track and field at George Mason University four years ago, his job was to take that athletic program "from nowhere to somewhere." At the time the school had no track facilities to speak of, and few quality athletes.

Today GMU has a $600,000, eight-lane track with four runways for the pole vault and jumping events. And in May it expects to open its new, $4 million field house with a 200-meter track, basketball, tennis and volleyball courts and baseball and softball diamonds.

In addition to improving its facilities, GMU has improved the quality of the athletes it has been attracting. The school now has a track team capable of gaining national attention.

Most notable among the track athletes is Emanuel (Skeeter) Jackson, a 20-year-old junior who recently became the first George Mason athlete to qualify for national competition in an indoor field event by recording a triple jump of 51 feet, 10 inches--good for second place in the East Coast Championships.

Jackson is an excellent illustration of how Cook is leading the Mason program "somewhere."

In the spring of 1978, Jackson, then a junior at Stafford (Virginia) High School, drew attention from coaches throughout the country with his all-around athletic ability. He was a wide receiver on the football team, a guard on the basketball team and a jumper on the track and field team.

"But before Skeeter's senior year, he hurt his knee and had it operated on," recalled Cook. "Other schools lost interest in him. We checked with his doctor, who said the knee would be fine, and that was all we needed to hear. We offered him a scholarship while he was still in a cast."

Jackson completed his high school athletic career with eight varsity letters in three different sports.

Though he did not play high school baseball because it interfered with track, during the summers he played American Legion ball well enough to interest professional scouts. The Baltimore Orioles signed him in 1981 and he spent last summer in Bluefield, W. Va., playing center field in the Rookie League (collegiate rules allow college athletes to play a sport professionally as long as they do not compete in that sport on the college level).

"I didn't want to hear too much about him playing baseball," admitted Cook, who was afraid of losing his prized performer to the pros or--worse--to a baseball injury. Cook felt the same concerns when Jackson caught the eye of George Mason basketball coach Joe Harrington while playing pickup games in the gym.

But the Orioles released Jackson during the winter, and he says he has been playing considerably less basketball, with "no regrets."

"I've been concentrating on my jumping by doing weight training and speed work," said Jackson. He is a physical education major and competes in the triple jump, long jump and high jump. "Within the next year, I guess I'll have to specialize in one jump and concentrate on it. That's my best chance of qualifying for the Olympics in 1984."

Choosing one jump may not be easy since Jackson has been outstanding in all three:

* While a freshman, he set a high-jump record of 7 feet, 1 1/4 inches in the Rutgers Invitational Meet.

* Last year he was state collegiate indoor champion in both the high jump and the long jump and was outdoor champion in the triple jump.

* This year, Jackson made athletic history at GMU with his indoor triple jump of 51 feet, 10 inches--also a Virginia intercollegiate record.

"We have a problem in that sometimes we try to do too much with him, he's so good," said Cook. "His best long jump is 24 feet, 3 inches. No one on the East Coast has gone over 25 feet; and 25-2 would qualify him for nationals. He could do it.

"The triple jump has three variables. If you improve a foot in each, that's three feet. He's done 51-10, and 54 feet is world class. If he builds his strength . . . .

"He hasn't high-jumped in a meet this spring, but he's gone over 7 feet in practice and he's already done higher competitively."

This weekend Jackson will represent George Mason in the highly competitive Penn Relays at Philadelphia's Franklin Field, participating in both the high jump and long-jump events.