https://speedendurance.com/2011/04/18/training-for-400m-balancing-speed-and-special-endurance-lactate/
https://speedendurance.com/category/400-meters/
http://www.ustfccca.org/assets/symposiums/2012/PDFs/Grigg-Ron-400-meter-training.pdf
https://speedendurance.com/2011/04/18/training-for-400m-balancing-speed-and-special-endurance-lactate/
https://speedendurance.com/category/400-meters/
http://www.ustfccca.org/assets/symposiums/2012/PDFs/Grigg-Ron-400-meter-training.pdf