^ Yes, the reduction in bat speed is fairly small. However, this tends to bust the myth that the weighted swings on-deck will result in faster bat speeds at the plate. The important difference appears to be that the batter's
timing is adversely affected (not that his bat swing speed changes only slightly).
I'm willing to bet that the video was somewhat staged so that it could slickly packaged -- it was meant to be representative of what has been seen in the lab. I'm curious tho' -- when bat speeds are talked about is it consistent? Are they
always talking about the tip of the bat where the linear (or tangential) speed is the greatest or is it measured at one of the "sweet spot" nodes where the ball is usually struck?
if training with a weighted racket slows down your swing speed, what can i do to increase my swing speed. does this also mean that any training with traditional weights (eg. dumbells) for my arm will also harm my swing speed, since according to the video, it will produce more slow twitch muscle fibers.
It's a bit more complex (& confusing) than that. The categories, slow twitch and fast twitch, are broad and refer to relative
contraction time of the muscle fibers. I may be wrong about this, but I believe that contraction time and speed of motion are not necessarily the same thing.
Our skeletal muscles are actually comprised of 3, possibly even 4,
muscle fiber types -- type I (slow), type II-a (medium fast), type II-x (fast), and possibly type II-c. Some mammals also posses type II-b (very fast) fibers. Note that slow twitch fibers, which are used for endurance & aerobic activity, do not grow appreciably in size. This can be confirmed by looking at the physique of long distance runners who have a very % of slow twitch fibers (particularly in their legs). These would tend to be developed with very low weight loads and very high repetitions.
For tennis, I suspect we may need
some slow twitch fibers. However for the burst endurance and for the explosive energy needs in tennis, we probably recruit a high % of both type II-a and type II-x fast-twitch fibers. It is possible that we might also possess type II-c fibers which can be trained or utilized as slow or fast twitch muscle fiber.
I also suspect that for different swing speeds and different swingweights, we would employ varying percentages of the 3 (or 4) muscle fiber types. I will try to get more into all of this stuff in another post.
Did you look into the
OU training that I mentioned in my previous post? With this training, you might try shadow swinging with your regular fame without strings for the underload phase. This would represent a 5-6% reduction in weight and a bit less air drag (due to the absence of the stringbed). Alternately, you could swing a lighter racquet -- one that has a swingweight that is 10-15% less than you regular playing racket. Not sure if these underload swings would be done with or without a ball -- I would think that it would be best to do these as shadow swings (no ball).