Lydiard recommends keeping supplemental training during the base phase inside the "alactic" zone. When looking at weight training this means an athlete will typically use close to maximal loads with reps in the 3-7 # range and allowing for full recovery. This rep scheme prevents the body from experiencing acidosis and yet still stresses the II B muscle fibers.
My question is about "core" training during the base phase. How do you approach core training if Lydiard recommends avoiding exercises that last longer than 10 seconds? Typically I do planks, bridges, crunches, twists, holds for time, etc...None of these are acceptable options during the base phase however. How do fellow Lydiard enthusiasts adjust for this?