This study showed the kinetic parameters at 150m and 350m during a 400m race. The male subject was the 44.94 by Thomas Schönlebe and the female subject was the 48.56 by Marita Koch.
The study was from “Incidenza dell’allenamento di forza su alcuni aspetti structurali delle prestazioni dei velocisti – esperienze degli allenatori della RDT” (Harmut Müller, Atleticastudi, 1, 1987 pp 25-58).
Thomas Schönlebe won the gold medal at the 1987 World Championships in Rome where he set a new European record of 44.33 sec that still stands today. At the 1993 World Championships in Stuttgart, he earned a bronze medal in the 4x400m relay.
Marita Koch set the current 400 meter world record of 47.60 seconds at the 1985 World Cup in Canberra, AUS. This performance is highly controversial due to the alleged drug use, and many people believe it should be wiped from the record books. In comparison, USA’s Sanya Richard’s PB is 48.60!
With all the talk about reducing ground contact time, you are probably wondering what is the correlation between Ground Contact Time, Stride Length and Fatigue in the 400m?
The 2nd 100 meter segment is considered the fastest of all 4 100 meter segments in a 400 meters, with the 150 meter mark being the fastest. Conversely, the last 50 meters in a 400 meters is the slowest (unless you are Butch Reynolds!).
Thus the study used 150m and 350 meters as key markers.
Note how stride frequency does not change, but velocity, stride length and ground contact time degrades.
So there to you have it.