Baseball: Relationship between upper body strength and bat speed

This study investigated the relationship between upper body strength and bat speed in high school players [1].

Study: The authors set out to examine the relationship between measures of upper body strength  and bat speed.  They took 30 high school players and split them into the players whom hit for more power (home runs) (n=14) and those whom were considered mediocre hitters (n=16).  They tested each player for the following:

Bench press 1 repetition maximum
Isokinetic Testing at 3 speeds: low, middle, and high
Bench press power using a load of 30 kg, peak power and peak velocity were measured

Results:  The results of this study are a little tricky to report so bear with me, so I will report them in a list like fashion to try and avoid confusion.

1RM was found to be moderately and significantly correlated to group B bat speed (mediocre hitters)
Swing speed, bench power, and fast isokinetic chest press under per kilogram of body weight showed significantly larger values in group A vs group B
Group A weighed significantly heavier than group B
There was a 10 kg difference in 1RM bench press in group A vs group B in absolute terms (not taking body weight into account).  When relative strength was taken into account (body weight) the difference disappeared.
In terms of bench power, there was a relative difference.  Meaning, group A could move the weight faster per bodyweight verses group B.

This is where it gets confusing, the authors report this:

“Bat swing speed showed significant correlations with the 1RM BP, isokinetic chest press, and bench power in the absolute values but only did so with isokinetic chest press (1.2 m·s⁻¹) in the relative values.”(Miyaguchi, K., & Demura, S., 2012)

“On the other hand, in the relative bench power values, there was a significant and marked difference (ES: 4.75) between group A (12.8 W) and group B (11.0 W). “(Miyaguchi, K., & Demura, S., 2012)

Was the bench press power in relative values significant or not?

Looking at the author’s table and values of 12.8 and 11 W it seems like they may have meant in absolute terms.  As the table with relative values indicated a nonsignificant relationship.

What to make of all this:   Well, it definitely appears that strength plays some sort of a role in hitting a baseball far.  This study  presents the results in a somewhat confusing manner and which is not reader friendly.   Overall, it appears general strength plays a role in developing power as a hitter but there are many other factors which play a role.  I think the results from this study highlight this factor.  Not only is it important to develop a good base level of strength, but it is important to develop the ability of the muscles and nervous system to fire faster.  This is supported by the fact that group A not only was stronger in absolute terms, but could move the weight faster per kg of body weight during the fast isokinetic test.  The author’s conclude that the bench press is an important exercise for baseball players.  In my opinion, I don’t necessarily believe this to be true.  There are many ways you can develop upper body strength, and ways in which are probably safer for the shoulder.  This comes down to individual comfort level with the bench press.  Some guys never really feel comfortable doing the exercise, in this case it would be much better to utilize something like a weighted push up which allows more free motion of the shoulder blades.  If an athlete feels comfortable with the lift, then by all means utilize it.

1.  Miyaguchi, K., & Demura, S. (2012). Relationship Between Upper-Body Strength and Bat Swing Speed in High-School Baseball Players. Journal of Strength and Conditioning Research, 26(7), 1786-1791. doi:10.1519/jsc.0b013e318236d126