She ran the 100 meter in 10.96-seconds at the 1987 Cologne Grand Prix Track and Field Meet, a personal best but the mark was not even in the top 40 of all time. She continued to improve, again setting a personal best of 10.89 in the 100 meters in San Diego on June 25, 1988, but still remained shy of then American record holder Evelyn Ashford's three best times. A week before the trials she ran a tune-up race in 10.99 in Santa Monica. In the first race of the quarterfinals of the U.S. Olympic Trials, she stunned her colleagues when she sprinted 100 meters in 10.49 seconds, a new world record by a margin of 0.27s over the previous record held by Evelyn Ashford. Over the two-day trials, Griffith Joyner recorded the three fastest times for a woman at 100 meters: 10.49 in the quarter-final, 10.70 in the semifinal, and 10.61 in the final. At the same Olympic trials, she also set an American record at the 200-meter distance with a time of 21.77 seconds. The 100-meter record was by far the largest improvement in the world record time since the advent of electronic timing, and still stands. This extraordinary result raised the possibility of a technical malfunction with the wind gauge which read at 0.0 m/s - a reading at odds with the windy conditions on the day, with high wind speeds being recorded in all other sprints before and after this race as well as the parallel long jump runway at the time of the Griffith Joyner performance. All scientific studies commissioned by the IAAF and independent organisations have since found there was an illegal tailwind of between 5 m/s – 7 m/s at the time. The IAAF has not annulled the result, but since 1997 the International Athletics Annual of the Association of Track and Field Statisticians has listed it as "probably strongly wind assisted, but recognized as a world record." The fastest non-wind-assisted performance would then be Griffith Joyner's 10.61s in the final the next day. This mark was equaled by Elaine Thompson-Herah in the 2020 Olympic Final before being surpassed by Thompson-Herah at the post-Olympics Eugene Diamond League meeting in August 2021. Thompson-Herah clocked 10.54 seconds, officially the second fastest time in women's 100 m history. Following the Olympic trials, in late July 1988, Griffith Joyner left coach Kersee saying she wanted a coach