relation/transfer of training tests and 40 yard dash

If muscular mass and power was built for a time leaving speed relatively neglected, how would the results coming from the reemphasizing of speed vary from what would have been obtained with a more modest weights program used with sprinting over the entire period?

Isn’t weight work and tempo without much sprinting or reactive work what is primarily done during an injury period? Is this muscle functional or are the weights done mainly for CNS purposes during this time?