Lower Body Strength leads to Improved Sprinting Speed (Scientific Review)
A recently published review paper from the peer reviewed journal "Sports Medicine" has confirmed what we already knew - stronger legs make better sprinters.
The review paper looked at 15 studies which in total involved 510 participants. While the strength training protocols varied (type of resistance used and duration of study were the most common variables) the statistics were solid overall in that the average improvement in sprinting speed was just over 3%.
I have a feeling that a very targeted approach to strength training that involves both heavy loading and velocity loading would have a much greater effect than leg pressing and extensions for general strength, however the paper didn't flesh that part out.
If you're interested in geeking out on the actual science and stats, here's the link to the abstract: http://www.ncbi.nlm.nih.gov/pubmed/25059334 . You can purchase a full PDF if you like also and write a bunch of paragraphs explaining the finer details of the statistics to me :)