What are the Optimal Biomechanics of a Softball Pitch?

What are the Optimal Biomechanics of a Softball Pitch?

 

INTRODUCTION:

Even though softball is classified as a team sport with nine players taking the field, each different position on the diamond plays their own individual role in the success of the team. The game of softball cannot occur however without the position of the pitcher, placed in the centre of the diamond and controlling the pace of the game and able to dominate like no other player is able to do. Because of the nature of the game, softball is generally quite low scoring, with some teams only managing to score one or two runs for the duration of the game and this is often due to the ability and skill of the pitcher. It often takes pitchers years upon years to perfect their technique and ability to gain control over speed, direction of the pitch and spin applied to the ball. Differing to the sport of baseball where pitchers overarm throw the ball, pitchers in softball use an underarm motion, most commonly known as the “windmill pitch”. This technique can often cause stress to the shoulder joint and elbow joint as much off the final effort comes from these two joints in action. A softball pitcher may pitch as many as six 7-inning games during a weekend tournament; and often the best pitcher on a team pitches most, if not all of the games each season (Werner, Guido et al. 2005). This may result in approximately 1200-1500 pitches being thrown in a 3-day period for a windmill pitcher, as compared to 100-150 for a baseball pitcher (Werner, Guido et al. 2005). 
The softball pitch is a relatively simple motion, consisting of a step forward from the mound onto the foot on the non-pitching arm side, weight shift onto this foot, and rotation of the shoulders and trunk to a position facing the batter. The pitching arm movement follows the rotation of the trunk, and is produced by forceful shoulder flexion, medial rotation and lower arm pronation during release. Skilled softball pitchers can release the ball at a speed of 55 miles/hour, or 25 m/s. Previous studies have reported an average release speed of 25.83 m/s, and a range of 23.7 m/s to 27.7 m/s (Werner 1994)
 

MAJOR QUESTION:

The purpose of this blog is to investigate the optimal way to pitch a softball. Guided by biomechanics this blog will demonstrate how to pitch a softball consistently accurately and with good speed in order to trouble the opposing batter.  The 'windmill' softball pitch is the standard pitching technique as the rules of softball specify that the pitch must be underarm.  Maffet et al (1994) describes the windmill pitching motion in terms of six motions that correspond to intervals on a clock.  For a lateral view of a right handed pitcher please see figure one.

Figure 1: Maffet's 6 phases (1997) 

This six motion model will be adapted to our own variation in this blog and these six motions will be elaborated on and discussed using biomechanics.  Stage 1 will involve the wind up at the very beginning of the pitching motion, phase 2 6-3 o'clock, phase 3 3-12 o'clock, phase 4 12-9 o'clock, phase 5 will detail the ball release and finally phase 6 will elaborate on the follow through motion.


ANSWER:
Phase 1 - windup:

A pitcher’s initial stance should have feet shoulder-width apart, facing the direction of the batter, with both feet touching the rubber plate. In the wind up phase of the softball pitch, a crucial technical element is the pitchers contact to the ground with their back foot; which is the right foot if you are right handed (Alexander and Taylor 2012). This contact with the ground acts as a generator for the start of the momentum and the beginning of the pitching motion. Much like when an 100m runner makes contact with the ground, when the pitcher's back leg pushes off the ground it creates a reaction force; which therefore gives the pitcher momentum (Blazevich 2010). This helps increase the momentum change from linear to angular. As linear momentum is a product of both mass and velocity and is generated vertically at the beginning of the pitching technique, when the wind-up sequence is performed (Papas 2014). After the wind-up sequence transitions into the full windmill technique, the pitcher transitions into angular momentum as the hips, torso and finally shoulders rotate to complete the pitching action. This is why the beginning stage is crucial to the overall performance of the pitch, as the force generated and momentum transition increases the overall accuracy and velocity of the pitch. To optimise success, coaches should tell athletes to put greater emphasis on the "push-off" with the back leg, and use the skill cue of "feeling it in your quadriceps" to guide the pitcher to correct technique.  

Figure 3: Angular momentum change

Figure2: Linear momentum

 

 

 

 

 

 

 

 

 

 

Phase 2 - 6-3 o'clock, the forward stride:

What many beginner pitchers do not realise is that majority of the power and velocity that is produced in the pitching action does not come from the arms, but from the power within the legs and through to the hips and torso. Typically, those with longer stride lengths exhibit greater vertical forces and overall ball velocity than those with shorter stride lengths (Olivera and Plummer 2011). In the second phase (6-3 o’clock) the pitcher uses the power from the quadriceps, gluteus maximus, through to the torso during the angular momentum phase of the technique. During this phase, the length of the stride can majorly influence the overall velocity of the pitched ball as it controls the hip and trunk rotation and therefore increases the distance the ball may be accelerated (Australian Sports Commission 1998). Turning the body sideways enables hip and trunk rotation to contribute to the speed of the ball at release, as well as increasing the distance through which the ball can travel and can consequently be accelerated. When the back leg pushes off of the pitching mat, the striding leg attains vertical velocity (drives the athlete forward), which therefore manipulates the centre of mass higher and this velocity is transferred to the pitching arm and finally to the velocity of the ball. The length of the stride contributes to the overall performance of the pitch as the stability of the pelvic area is important for efficient energy transfer up the kinetic chain from the hips to the pelvis and scapula, onto the shoulder, elbow, hand and wrist for the ball release (Olivera and Plummer 2011). Therefore as shown in Figure 4, a greater stride length will transfer into an overall higher ball velocities. To guide the athlete, the coach or teacher should first teach the athlete to "push off" with their back leg then thrust their guiding leg out as far as they can. Coaches can also put markers down on the ground to push athletes to stride as far as they can to gain further speed and momentum on the pitch.

Figure 4: An example of phases 1 and 2 in sequence

Phases 3 and 4 - 3-12 o'clock and 12-9 o'clock, shoulder rotation:

As you pitch in a windmill motion the pitcher generates momentum that increases the velocity during the release.  The pitcher's shoulder acts as the fulcrum as the surrounding muscles contract putting forth effort to create some torque around the joint, the higher the velocity of the windmill the more momentum the pitch generates (Hasselbach, 2014).   Pitchers with faster shoulder rotational speeds at release were found to have lower ball velocities at release (Werner, Murray et al. 1997).  Therefore the windmilling speed of the throwing arm just prior to release of the ball should be decreased. This deceleration of the shoulder rotation may allow some of the speed of the arm motion to be transferred to the ball, thus increasing the final velocity of the ball upon release (Alexander and Haddow 1982).  Blazevich (2010) elaborates on the mechanics of a throw-like pattern.  The kinetic chain theory describes the transfer of momentum from a fulcrum (in this instance the pitchers shoulder) to the finishing point of a movement sequence, in this case the momentum (and increasing velocity) travels through the shoulder and arm until the pitch is completed. Blazevich (2010) asserts by stating "one theory is that momentum generated in the proximal segments [body segments closest to the beginning of the movement] through the production of large muscle forces is transferred to the distal segments [body segments further from beginning of the movement], much like the transfer that occurs in a fishing rod".  

Figure 5: 3 o'clock to 9 o'clock 

     
Phase 5 - Ball release:
In the fifth phase (9 o’clock – ball release) of the pitching technique a crucial component is the flexion and extension of the elbow and the flexion and extension of the wrist into the “snap” component of the pitch. As the shoulder joint rotates from the 9 o’clock position through to the ball release, the elbow transfers from being fully extended (straight) to flexed right before the ball is released. This sudden flexion transfers a quick reaction from the wrist; making the wrist “snap” (see figure 6) from being fully extended to fully flexed (Alexander and Taylor 2012). If this element of the technique occurs too quickly in the kinetic chain there will be minimal contribution by the wrist joint to the overall pitch. To counteract this, a technique change can be made with pitchers to delay the “snap” of the wrist, so the correct timing is harnessed and the ball travels at a higher velocity. A coaching cue that can be given to the pitcher is to only flex the wrist once the pitcher’s inner forearm brushes the hip of the pitching arm side. This allows the athlete to use intrinsic feedback and improve their performance without direct influence from their coach (Button, Flyger & Rishiraj 2006). Once the technique is completed, the body will have fully rotated, with the closing of the hips and shoulders in rotation so they are facing the initial direction of the pitching sequence, with weight landing on the striding leg.

Figure 6: Wrist action

The culmination of the above phases if performed correctly can result in a pitch of great speed. On average elite college softball pitchers throw 60-70mph. A 68 mph pitch has a linear velocity of 30.4m/s.  The mound is 43 feet away from home plate which is 13.1 metres of displacement, this means the batter has 0.43 seconds until the ball meets the catcher’s glove.  There is not a lot of time to decide and react as a batter, the best pitchers throw balls at speed and that move making the ball difficult to locate.  The fastball has an acceleration of 70.4m/s squared.  Knowing the acceleration and the mass of the softball the force of the pitch can be found (F=13.5N) (Hasselbach, 2014).  Pitchers like these have pitches such as a riseball, curveball, dropball amd screwball in a changeup.  Air affects the flight of all projectiles, and in this case the ball pitch is being persuaded by the magnus force.  The spin of the ball has a significant influence on the ball’s flight path and trajectory (Wu & Gervais, 2008).  As a ball spins towards homeplate there is a force acting perpendicular to the balls axis, air is flying around the ball from front to back.  Air from the top of the ball is flowing in the same direction that the ball is moving, while air from the bottom of the ball is being dragged in the opposite direction because of the friction with the balls surface.  Pitchers can manipulate the path their ball takes by taking advantage of the magnus force (Blazevich, 2014).  The sideways component of the airflow carries momentum in that direction, and since momentum is conserved, the ball must recoil with an equal but opposite momentum. This is the Magnus effect (Griffiths, Evans & Griffiths, 2005). 

Figure 7: The magnus force

Phase 6 - Follow through:
The purpose of the follow through is to decelerate the pitching arm over the greatest possible time and distance, to decrease the force and to help reduce the chance of injury. All of the pitchers weight should now be shifted to the front leg, and the back foot should slide forward to a position just behind the front foot. There should be no weight remaining on the back leg during the follow through (Alexander & Taylor, 2012). Hay (1973) also emphasises that the primary function of the pitching follow through is to reduce the speed of the body (in particular the pitching arm) in order to reduce the risk of injury. Hay (1973) also touches on the significance the follow through being performed correctly so as to not impair the application of forces to the ball and to enable the pitcher to move into a position where they are ready to field as quickly and efficiently as possible. See figure 7 for a good example of the follow through, weight has been transferred to the front foot and the back foot is off the ground.

Figure 8: A good example of the follow through 

See the below video for a demonstration of the optimal pitching technique given by Jennie finch, two time Olympic athlete.

HOW ELSE CAN WE USE THIS INFORMATION?

Injury prevention:
It became obvious to us at the beginning of this blog that the rate of injuries among softball pitchers is quite high and a lot of this can be attributed to poor pitching technique.  The biomechanics of the windmill pitch places a large demand on the shoulder joint, This demand leads to increased flexion at the elbow joint leaving the shoulder structure vulnerable to chronic injuries. This has important implications for injury prevention, strengthening and rehabilitation of the rotator cuff complex and elbow flexors (Button, Flyger & Rishiraj, 2006).   Meister (2000) states that shoulder injuries could also be a result of poor mechanics and adequate conditioning.  The information in this blog can therefore be useful in injury prevention as the use of good pitching technique can help prevent injuries.  Additionally though biomechanical analysis information of the principles will allow coaches and teachers to educate learners on how to execute the skill of pitching successfully.  


SUMMARY:

The softball pitcher is the key player on all softball teams, and the strength of the team is directly related to the skill of the pitcher. Windmill pitching in softball is an exciting and dynamic skill that requires many years of practice to perfect. Players have to practice their pitching using the correct sequence and timing of the key joint movements, as highlighted throughout this blog. Players also have to work on their strength and physical conditioning, as increased muscle strength in the muscles involved in pitching will further improve effectiveness and will aid in injury prevention as previously discussed. Within great windmill pitchers there are certain movements (biomechanical) that are necessary for all pitchers, despite this there is still some room for variability to allow for unique movements that may be useful for certain pitchers with individual styles.

REFERENCES:

Alexander, M. J. L. and C. Taylor (2012). Softball Pitching Technique. University of Manitoba, Faculty of Kinesiology and Recreation Management.

Papas, M. (2014). "On Linear Momentum and Angular Momentum." Retrieved 15/5/2015, 2015, from: http://www.revolutionarytennis.com/Rev%20Tennis/download/Linear%20and%20Angular%20Momentum.pdf.

Alexander, M. J. L. and J. B. Haddow (1982). "A kinematic analysis of an upper extremity ballistic skill: the windmill pitch." Canadian Journal of Applied Sport Sciences 7(3): 209-217.

Australian Sports Commission (1998). Biomechanical Analysis of Softball Pitching Technique. N. S. R. Centre. Sydney, Australian Sports Commission.

Blazevich, A. (2010). Sports biomechanics, the basics: Optimising human performance. A&C Black

      Button, C., Flyger, N., & Rishiraj, N. (2006). The science of softball: implications for performance and injury prevention. Sports Medicine, 36(9)

      Griffiths, I ; Evans, C ; Griffiths, N (2005) "Tracking the flight of a spinning football in three dimensions". Vol.16(10), pp.2056-2065

Hasselbach, T. (2014) "MOVESCI 330: "Biomechanics of a softball pitch". Retrieved from: https://www.youtube.com/watch?v=Kyy4DaQUdcE 

Hay, G. (1973). The Biomechanics of Sports Techniques. Prentice-Hall Inc. Eaglewood Cliffs, N.J. 

Maffet MS, Jobe FW, Pink MM, et al. (1994). "Shoulder muscle firing patterns during the windmill softball pitch." Am J Sports Med.

      Meister, K. (2000) Injuries to the shoulder in the throwing athlete. Am J Sports Med 2000; 28 (2): 265-75

      Olivera, G. D. and H. Plummer (2011). "Ground reaction forces, kinematics, and muscle activations during the windmill softball pitch." Journal of Sports Sciences 29(10): 1071-1077.

      Tom Wu & Pierre Gervais (2008) An examination of slo-pitch pitching trajectories, Sports Biomechanics, 7:1, 88-99

Werner, S. L. (1994). "Biomechanics of pitching- An analysis of the windmill pitch."  FastPitch World (July): 21.

Werner, S. L., J. A. Guido, et al. (2005). "Biomechanics of Youth Windmill Softball Pitching." American Journal of Sports Medicine 33(4): 552-560.

      Werner, S. L., T. A. Murray, et al. (1997) Report to the coaches: softball pitching at the 1996 Olympic Games www.steadman-hawkins.com.