I'm certainly no batting expert and I was having difficulty with Consultant's description of the tire drill. I thought I knew what "swing thru" meant but I couldn't visualize how that worked with a tire strapped to the trunk of a tree.
So, I did a little Googling and found this:
The Baseball Drill Book - Google Books Result
by Bob Bennett, American Baseball Coaches Association - 2004 - Sports & Recreation - 320 pages
166 TIRE DRILL Focus To complete the swing and develop power through resistance. ... Procedure The hitter works on making the tire spin by driving the bat ... The image of the page was blocked on my gov't computer, so I tried
Amazon. I was able to see there that the author suggests building a contraption with poles and concrete and 2 tires.
It made me realize that Bob was really saying to
hang a tire from the branch of a tree.