That sounds reasonable, and would apply over several seasons as well. In other words, within a given season, the deadlift volume would drop as speed work picks up, and from season to season the deadlift volume would go down as the athlete becomes faster.
Regarding increased strength with less relative increase in bodyweight, I think this has to due with the fact that the deadlift doesn’t really have an eccentric phase. The lowering is more of a controlled drop (for some people, not that controlled), similar to olympic lifting. The deadlift seems to be one of the few lift where I’m stronger concentrically than eccentircally, simply because of the mechanics of the lift.
The power in sprinting comes primarily from the pulling muscles on the back of the body, although the whole body is involved, just like deadlifts. However, the greater specificity is relative. All weightlifting is general to sprinting.
A couple years ago we had a thread going on the relationship between pulling exercises and sprinting where Charlie raised many of these points.
The word specific should not really come into the discussion, I think it is a question of exposure. Which exercise recruits a muscle in a way that will be more beneficial to sprinting. I thought the erector spinea did not play a part either, but remember that to have a high hip carriage and optimal knee drive and hip extension, the ES have to hold your torso like a pillar. Also they aid in applying force at toe off. by rotating the pelvis forward when the hip is held stationary causing the leg to move backward . Any slight movement in the pelvis will cause a relatively large displacement of the foot. Med ball throws will train the ES also.
Always remember that all weightlifting is general to sprinting as flash said, so its not a questions of specific training. Its about general strengthening and CNS loading.
I don’t agree that this is a hard and fast rule. I have done plenty of of deep squats (well past parallel) and I’ve never had sore hamstrings. The soreness is always concentrated in my quads and hip extensors.