Hi Phil
Analytic study of elite 400m performances from both genders over an extensive period of time has revealed that an ideal, evenly run competition performance should be based on the average 100m split of the required finishing time.`
These splits show slight variation which may be further amended to suit the training status/capabilities of the individual/developing athlete.
The first three ideal splits are: 98-101% of average split; 104-106%; 101-103%. The final split is tolerated rather than scheduled and there is a marked falling away of percentage as the tiring athlete attempts to hold the performance together the best s/he can and, if the planned percentage targets are adhered to, normally results in 92-93% of the average split.
Example:
Michael Johnson: 43.18WR -Average split (rounded up fractionally) = 10.8
WR performance actual splits:
First 100m = 11.1 (c 98%)
Second 100m = 10.12 (c 106%)
Third 100m = 10.44 (c 103%)
Fourth split = 11.52 (c 93%)
Based on the above, I usually advise developing 400m runners to aim for percentage splits of 100% (brisk start with caution, aim to be in good condition at 300m); 105% (challenge, rather than attack the back straight); 103% (relax on the bend, take a mental breather!); 92-93% (don’t fight your technique, relax and make do with what you have left in the tank!!)
For a 50 second performance this breaks down as: 50/4 = 12.5
[12.5; 11.9; 12.1; 13.5]
Persevering with the average splits for the first 3x 100m allows the athlete to develop anaerobic status over an extended period of time and eventually to have more in the tank for the final straight, which is where the greatest improvement in performance time will be achieved.
I hope this is of use/interest to developing coaches and athletes alike!