Following
Part I, let's look at the different phases of windmill pitching with special attention to a few instances where strength and conditioning coaches can really benefit a softball pitcher's capacity and technique.
If you are unfamiliar with the windmill sequence, please review
Part I, so this information doesn't come out of left field.
Wind up –
-Variable
-Load/prep of the back leg to drive off rubber
Stride to Lead Foot Contact –
-Drive off rubber with back leg, propelling the body in a straight line toward home plate

This movement is very explosive and results in pitchers reaching stride lengths between 80 and 100 percent of the body height. Full hip extension on the back leg is required for maximal power and lumbar stability.
-Pitching arm will travel from 6 o’clock to 12 o’clock (between 160-180 degrees of flexion/abduction)

In this position, thoracic mobility are scapular stability are critical, as well as multi-segmental extensibility across the anterior functional fascial lines (see: Anatomy Trains).
-Body turns toward third base
-Lead leg lands with knee slightly flexed (around 30 degrees)
Here, single leg strength and joint stability are required for efficient energy transfer from the stride leg into the upper body.
One way I explain the consequence of joint instability to young athletes is using a "sand pit" analogy. Movement with joint instability is like testing vertical jump in a sand pit. Performance is inhibited (can't jump as high) because the sand gives out underneath the feet. Jump performance improves on solid ground because the interaction between the feet and ground is stable. If any joint "gives out" during the push of the rubber or during landing of the stride leg, maximal velocity will never be obtained and an overuse injury is likely to appear.
-Lead foot lands internally rotated (around 30 degrees) toward the third base side
-At lead foot contact, pitching arm will be at 12 o’clock
-Lead arm points toward home plate
Delivery to release –
-Pitching arm travels from 12 o’clock to release very close to the plane of the body
Core stability, thoracic mobility and proper scapular loading will allow the arm to "track" correctly toward the target (catcher). From 12 o'clock to release, the shoulder and elbow endure the largest distraction forces throughout the delivery. Biceps activity peaks during this phase as it contributes to the stability to both joints.
-Elbow may be slightly flexed and elbow/wrist position will vary at release depending on the pitch thrown
-Lower trunk will rotate (20-45 degrees) toward home plate up to point of release

During the delivery, the upper and lower torso separate. This dissociation leads to a stretch and subsequent stretch-reflex contributing to pitch velocity. The pec major is the primary engine which flexes the arm in this movement; however, its power is determined by the muscular teamwork behind and below.
-Back leg slides (must maintain ground contract) in straight line toward lead leg
Follow through –
-Pitching arm (elbow/wrist) action is variable
-Back leg completes its slide, with the back foot contacting the lead foot
-Lower trunk completes its rotation toward home plate

Similar to other rotational movements, the trunk rotates into a stiff front leg. Once again, the pelvis and torso do not move as one unit. As you can see in the photo above, the pitcher's shoulders have rotated beyond her pelvis after releasing the ball which may help reduce stress to the pitching arm.
-Pitcher should finish “tall” into lead leg
-Pitcher will adjust back leg in order to prepare to field a batted ball
Coming up, I will review the most common pitching-related injuries, proposed mechanisms, assessments, restoration and preservation strategies. These future posts will include specific tests, corrective exercises, coaching-eye exercise corrections (notice the difference) and training strategies for youth, adolescent and elite level pitchers.