This specific topic was covered in the latest NSCA Journal of Strength and Conditioning Research:
Keogh et al. Kinematic Alterations Due to Different Loading Schemes in Early Acceleration Sprint Performance From Starting Blocks
10% BM load (Jakalski) may be more beneficial than 20%BM load, however, more research needs to be done.
Certainly, the loads used in the video were laughable, considering RFD, technique, amortization…could go on. Rediculous. I’ve seen this done by MMA Strength Coaches also, but someone training HS boys for speed acceleration should know better.