Average ball velocities differed between all three motions. The traditional throw down recorded an average ± standard deviation velocity of 29.9 ± 2.8 meters per second (m/s), ranking second fastest, just behind the pitch out’s 31.4 ± 2.6 m/s. Throwing from a kneeling position produced the slowest ball velocity of the three motions, 27.7 ± 2.2 m/s.
Figure 4-1. Ball velocity of the three throwing positions.
In the study, pop time was defined as the moment the ball was caught to the ball being leaving the catcher’s hand. Knowing the ball velocity and distance to second base, the time needed for the ball to travel to second base was calculated. Together, the total time to second base was determined. Observable differences were displayed between the traditional thrown
0 10 20 30 40
Throwing from the knees Traditional throw down Pitch out
Velocity (m/s)
*
down and throwing from the knee positions when pop time was analyzed. The traditional throw down recorded the slowest pop time of 0.79 ± 0.1 seconds, but with a time of 2.10 ± 0.1 seconds was the second fastest for the total time to second base. The pitch out clocked the second
quickest pop time, 0.77 ± 0.1 seconds, and produced the quickest overall time to second base of 2.02 ± 0.2 seconds. Throwing from a kneeling position generated the fastest pop time out of the three positions, however, it recorded the slowest total time to second base. The total time to second base for the pitch out demonstrated significant differences when analyzed with the two other positions. Nonetheless, the pop times of the traditional throw down and pitch out did not exhibit any differences. Although pop times for the traditional throw down and pitch out were slower than that of throws from the knees, with a significantly faster ball velocity allowed the two throwing motions to reduce the overall time to second base.
Figure 4-2. The total time to second base from the time the ball is caught to leaving the catcher’s
hand (pop time) and the time needed for the ball to travel 38.795 meters to second base (ball velocity).
The stride lengths of the traditional throw down and pitch out measured 1.22 ± 0.1 meters and 1.2 ± 0.1 meters, respectively. The traditional throw down’s stride length was 70.1% ± 2.0%
of the catcher’s height. The stride length for the pitch out in relation to the catcher’s height was 68.9% ± 2.0%. As the catcher progressed to the stride and arm cock phase of the throwing motion, the traditional throw down exhibited the highest average shoulder external rotation angle of 138.4 ± 12.8 degrees. The pitch out and throwing from the knees exhibited angles of 137.5 ± 11.9 and 135.1 ± 12.9 degrees, respectively. Shoulder extension for the traditional throw down and pitch out had observable differences, with the former having a higher shoulder extension of 21.7 ± 10.7 degrees and the latter of 20.2 ± 10.9 degrees. Differences were additionally observed
0
in the trunk lateral tilt to the left. Throwing via the traditional throw down demonstrated the most lateral trunk tilt. The pitch out recorded an average of 18.3 ± 5.2 degrees for trunk tilting to the left. Throwing the ball to second base from the kneeling position showed 11.5 ± 5.7 degrees of trunk lateral tilt.
Table 4.1
Comparison of Joint Kinematics Between Three Throwing Positions
Throwing from Elbow Extension Velocity (°/s) 1904.9 ± 234.9 2047.4 ±
219.5 2007.3 ±
In the arm acceleration phase of the throwing motion, only elbow extension and trunk rotation velocities exhibited significant differences. When the velocity of elbow extension was measured, the traditional throw down was faster than the other motions in the study, with an average velocity of 2047.4 ± 219.5 degrees per second. The pitch out recorded the second highest average elbow extension velocity of 2007.3 ± 202.9 degrees per second, and the knee averaging the slowest velocity of 1904.9 ± 234.9 degrees per second. Rotation velocities of the trunk from fastest to slowest ranks as follows: throwing from the knees, traditional throw down, and finally the pitch out, with velocities of 360.5 ± 40.9, 300.8 ± 39.3, and 288.7 ± 44.5 degrees per second, respectively.
0 100 200 300 400
Throwing from the knees
Traditional throw down Pitch out
Angular Velocity (° /s)
*
Figure 4-3. Trunk angular velocity measurements for the three throwing positions.
Differences were not observed for shoulder internal rotation velocity and trunk extension. As the ball was released, the pitch out and knee positions significantly differed in trunk forward tilt angles, with the kneeling throw demonstrating 8.9 ± 4.2 degrees of forward tilt. Shoulder internal rotation and elbow extension angles were similar and yielded no differences.
Note. Observed differences p <.05 Table 2
Correlation Between Joint Kinematics and Throwing Motions Parameters Throwing from the
knees Traditional throw down Pitch out
Velocity Ball Time Pop Ball Velocity Pop Time Ball
Figure 4-4. Relationship between traditional throw down kinematic parameters and ball velocity.
R2 = 0.672.
Figure 4-5. Relationship between pitch out kinematic parameters and ball velocity. R2 = 0.624.
The kinematics was further analyzed for influences on ball velocity and pop time with p < .05.
The traditional throw down reported an R-value of 0.820 and R2 of 0.672 for ball velocity. The pop time’s R-value and R2 for ball velocity are 0.835 and 0.696, respectively. Shoulder
abduction, elbow max extension, and shoulder external rotation positively correlated with ball velocity. Conversely, forward tilt of the trunk and elbow extension velocity negatively correlated with the traditional throw down’s ball velocity. Analyzing pop time, shoulder external rotation and lateral tilt of the trunk to the left were positively correlated. While angles of the shoulder abduction, elbow flexion, trunk forward tilt, and elbow extension velocity negatively correlated with pop time.
Throwing to second base via the pitch out produced an R-value of 0.790 and R2 of 0.624 for ball velocity, and an R-value of 0.801 and R2 of 0.642 for the pop time. Shoulder external rotation, shoulder abduction, and elbow extension displayed positive correlation, while trunk tilt to the left and elbow extension velocity negatively correlated with the pitch out’s ball velocity.
Pop time exhibited positive correlations with shoulder external rotation and trunk lateral tilt to the left. Negative correlation between the pitch out and pop time were observed for shoulder internal rotation and elbow extension velocity.
From the kneeling position, seven parameters had statistically significant correlations with the ball velocity and pop time when p < .05. The reported R-value and R2 values for ball velocity were 0.446 and 0.199, respectively. The pop time had an R-value of 0.750 and R2 of 0.562. Of the seven parameters, shoulder max external rotation, abduction, internal rotation velocity, and trunk angular velocity were positively correlated with the ball velocity. However, when the shoulder internal rotation angle, elbow flexion angle, and elbow extension velocity increases, the ball’s velocity will see a decreased value due to the negative correlation observed.
Pop time displayed a positive relationship with shoulder external rotation, trunk tilt to the left, and trunk angular velocity. Nevertheless, shoulder internal rotation, elbow flexion, and elbow extension velocity negatively impacted the pop time.