There was a consistent appearance 01 the lateral to medial jumps as a significant
factor correlated to high throwing velocity in each of the throwing techniques for both left
and right handed throwers (Tables 3-6). This was the first study to our knowledge 10
correlate throwing velocity to a unilateral jump in the frontal plane, which mimics the
action of the stride.
The importance of the stride was noted in a biomechanical study of the throwing
motion by Stodden et al. (2006) who notcd that the stride functions as the initial factor to
generate and transfer force of momentum up through the kinetic chain by initiating linear
momentum of the body towards the intended target. This need for linear velocity has
been reported with other throwing activities. Top lcvcljavelin throwcrs exhibited both
longer strides and higher approach velocities (Bartlctt et al. 1996) while Salter et al.
(2006) demonstrated that 87.5% of ball release speed for a cricket bowler can be
attributed to run-up velocity, angular velocity of the bowling arm, vertical velocity of the
non-bowling arm, and stride length.
This correlation between lateral to medial jump scores and throwing velocity is
congruent with the information provided by MacWilliams et al. (1998) which stated
increased ground reaction forces created by the trail leg in the direction towards the target
were highly correlated with ball velocity. Theoretically, the increase in momentum
would allow baseball players to transfer more energy through the kinetic chain from the
trunk. to the throwing arm, and tinally to the ball to produce increased ball velocities.
59
While the ability to generate momentum is important. one must be careful to not
artiticially produce linear momcntumlowards the intended target. MacWilliams ( 1998)
notcd that while the correlation of ground reaction force to throwing velocity was high
(r2=0.82) some subjects demonstrated the reverse trend with what the authors called
"overthrowing". The authors noted that the athletes must integrate the powerful leg drive
as a natural part of their throwing motion due to its complexity. lfpeak ground reaction
forces occur too early during the throwing motion. throwing velocity is reduced (Elliot et
al. 1988). MacWilliams et al. (1998) found that the forces were gradually built up and
peaked just prior to the le3d foot making contact with the ground. The need to crc3te
momentum towards the target is taught by some pitching coaches who stress the
involvement of the lower body by emphasising the need to "push" or 'drive" towards
the target as part ofa well-integrated pitching motion (Empey 2002).
Thc specificity of the lateral to medial horizontal jump may be the primary reason
that it correlated to high throwing velocity. The intuition ofa pitchers stride towards the
target is also Strength and conditioning coaches apply the principal of specificity to
athletes who desire the abili ty !O improve a specific task. The specificity principal
implies that to become better at a particular skill the training must involve the skill by
replicating the biomechanical movements (Young et al. 2001). Traditional bilateral tesls
such as vertical, horizontal jumping and running speed in the sagittal plane did not
signific3ntly correlate to high throwing velocity in the current study. These results agree
60
\jth the lindings oiSpamol (1 9'J7) who did not ri nd any correlation between ~ither
running speed (60 yard dash) or lower body power (vertical jump) and throwing velocity.
The correlation between throwing velocity and lateral to medial jumps suggest
that there is a high degree of specificity in regards to power in a specific direction and
plane of movement. The poor carryover from tra ining in one plane of motion and testing
in another has been shown by King and Cipriani (2010) who reported reduced
improvements in vertical jump scores of subjects that trained exclusively wilh frontal
plane plyometric exercises compared to those that trained in the sagittal plane. Young et
at. (2001) also found low transferability between linear speed and agility.
The results of this study also demonstrated that body weight played a significant
role in throwing velocity for right handed throwers from the stretch position (table 3) and
left handed throwers with a shuffle approach (table 6). These findings are congruent with
those from Werner et al. (2008). Increased body weight increases the total amount of
energy that can be ultimately transferred to the ball allowing for higher throwing velocity.
In each case that body weight was a significant factor it was also coupled with the lateral
to medial jump which indicates increased amounts 01 body mass must be accompanied by
the appropriate amounts of power. Added body mass in the fonn offat would be
beneficial as it can be assumed that it would decrease the latera! to medial jump scores.
Inc reased distance from a lateral to medial jump coupled with increased body weight
would again account for increased amounts of kine tic energy in the direction of the target
allowing for high throwing velocity scores
61
rnrowing a baseball with high velocity requires a complex combination of
kinematics and kinet Ics that must be in place In order to optimize the athlete"s abi lity to
transfer energy to the baseball. However if these molor patterns arc in place due to years
of practice the results of this study lead us to believe that increased levels of power in the
frontal plane result in higher throwing velocity scores. Future studies will have to
determine if increases in the athlete"s ability tojump further in the frontal plane will
translate into higher levels of throwing velocity.