RE points from the original blog:
What is the value of the prestretch in sport?
As you say this is matter of return on investment given how much can be gained in time to the ball by positioning and skill vs speed, the importance of speed to team sport performance, and also how much can be gained and how readily from improving gross power output compared to prestretch. In the context of team sports, acceleration is very often in the context of a cutting movement rather than continuing straight ahead as per a “false/split step”, and cutting requires deceleration first (i.e. velocity will approach a static start first) in the sagittal, frontal and transverse planes before acceleration can occur. Cutting will also involve a lowering of the COM, and give more quad/glute emphasis in the subsequent acceleration.
As such the prestretch requirements are less related to the triceps surae and much more related to slower eccentrics from the quads, glutes, hip abductors and hip rotators, and power output to overcome inertia is critical. While relevant “prestretch” qualities of the quads and glutes will likely be addressed through many conventional training methods, the related function of the hip abductors and extensors is due to many mechanisms covered in detail in ACL injury research.
The other important point is that the attentional demands of technical and tactical execution detract greatly from the potential for conscious sprinting technique during a game or play. Changing inherent qualities to a large extent will result in the best carry over when focus on technique is difficult, and large changes are generally more achievable in gross active power output rather than prestretch mechanisms. Compared to sprint specific prestretch, gross power output from positions of lower COM is generalisable to many sporting actions from jumping to low COM lateral movement (defensive shuffle positions in basically all team sports), to stability when making a tackle (whether it involves a collision as in gridiron/rugby or not as in soccer) and others. The two big areas for gains in “game speed” will tend to be
i) Concentric power output from hip and knee extensors for propulsion in a linear, lateral, and vertical direction with a bias to slow contraction velocity as most sprints are very short.
ii) Eccentric power output from hip and knee extensors for braking in the complex context of specific postures related to hip abductors and external rotators with some contribution from trunk and foot as well. In terms of return on investment this area also has big injury prevention relevance.
The video posted on Rodriguez and Ronaldo is relevant here, note force absorption into a squatting position and subsequent acceleration from that position again for efficient slalom running, compared to the heightened impact of sagittal prestretch in sprinting.
Pre Stretch vs Pre Tension vs Pre “Jerk”
I’d make a very clear distinction between
Pre tension: Which will exist in a static block start or snatch from blocks or certain sport postures.
Pre Stretch: A significant, controlled and co-ordinated movement which contributes to efficient performance in the concentric phase, like a “repeat hang snatch with a prestretch” or a countermovement jump.
Pre-Jerk: Poorly controlled movement lacking co-ordination which subverts the essential components of the concentric and leads to alters muscle recruitment. E.g. the “rocking” hang clean with a jerk forward and a loss of the hip and knee c-ordination inherent to Olympic lifts, with lumbar extension substituted.
Hang snatches are one option, though the amplitude of hip extension vs knee extension in a hang snatch may be somewhat different to block starts. It should be noted there is nearly always some countermovement from the body when lifting from blocks although the bar may not move. Another option is a push jerk (either split or squat landing) from a pause squat. Alternating Bench/step (30-40cm) jumps and conventional vertical jumps with a weighted vest can also be useful.