MONTE CARLO, Monaco (AP) _ Jackie Joyner-Kersee will lose her heptathlon world record at the end of the year because of a design change to the javelin.

The world governing body of track and field said Monday that a new javelin with a slightly different center of gravity _ allowing it to land more frequently on its tip _ will go into use beginning April 1.

Joyner-Kersee set the world record of 7,291 points at the 1988 Seoul Olympics. The javelin is one of the seven events in the heptathlon.

The new world record will go into the books Jan. 1, 2000, and will come from the best performance with the new javelin, which will not go as far as the old implement.

The current women's javelin record of 262 feet 5 inches, set by Petra Felke of East Germany on Sept. 9, 1988, also will be erased.

The IAAF made a similar change to the men's javelin in 1986, wiping out Uwe Hohn's throw of 343-10. However, Daley Thompson's decathlon record of 8,847 points _ set with the same javelin _ was allowed to stand.

``In effect, there will be new records,'' said Giorgio Reineri, an IAAF spokesman. ``It is not a political decision, it's a technical decision.''

Joyner-Kersee was not immediately available for comment.

Joyner-Kersee, who retired last year, won two Olympic gold medals in the heptathlon and one in the long jump.

Asked why the IAAF elected to keep Thompson's decathlon record, Reineri said, ``I think they (the technical committee of the IAAF) believed what was done 13 years ago was a mistake.''

Reineri said the marks of Joyner-Kersee and Felke would be noted in IAAF records ``as coming under different conditions.''