'with flying start, worth ~ 0.75s ( that is usual number used in a relay )'
Wrong the fastest ever relay split was 42.9 do you think MJ was never in faster than 43.65 shape for a relay
-> 51.64
knock off something for the wind & fatigue upto the bell ( very little as it was such a slow race, little more than a 400 time trial ) & i reckon he is in
~ 51-flat
The wind alone is worth .64 and the fatigue something similar. Add .5 for start deduct .64 x 2 and you are close to 50 flat. Add on that it was colder than ideal for a sprint and all best 400m times are run in middle lanes and he is dipping 50
For those who think 50.89 is not that impressive after such a slow race find a faster finish in any 5km race. There can't be many which is why he is double Olympic Champio and nearly got the WC double. It's not luck!