Hip To Shoulder Separation Increases Pitching Velocity And Reduces Injury
If you want to add velocity to your fastball and reduce your risk of injury, hip to shoulder separation is a must. Hip to shoulder separation is the transmission of the pitching delivery. It connects the lower half to the upper half and transfers freakish amount of horsepower between the two systems. It is an absolute vital component of healthy high velocity pitching. If you haven’t already, go back and read the article on back leg drive to learn how the drive leg helps to power hip to shoulder separation. This article will focus more on the trunk and shoulders role in hip to shoulder separation rather than the back leg drive and pelvis. Separating the hips from shoulders is the elite biomechanics movement that separates low velocity throwers from high velocity throwers and the timing of it plays a vital role in injury prevention, the stretch shortening cycle and velocity enhancement.
Stretch Shortening Cycle
The stretch shortening cycle is an eccentric ‘stretching’ action before a quick concentric ‘shortening’ action. The prior eccentric stretching (preload of the muscle) has been shown to enhance the performance of the final concentric phase in comparison to an isolated concentric action. For example, jump height improves 18–30% in adults when utilizing a countermovement compared to a jump with no countermovement. Fast stretch shortening actions promote greater movement speed via elastic energy usage, stretch reflex contributions and a greater level of neural excitation from the preceding stretch. In pitching, hip to shoulder separation allows the stretch shortening cycle to occur as the trunk and arm cock back to store elastic energy through the core and throwing arm. As the back leg drive accelerates the athlete down the mound and powers the pelvis open into front foot strike, the trunk and arm are loading in the opposite direction to store as much elastic energy as possible to enhance trunk rotation velocity. Think of it like a rubber band stretching before being fired to release the energy stored through the stretch. If you can picture that, you begin to understand how important hip to shoulder separation is to maximizing your throwing velocity.
“Separation between pelvis and trunk rotation creates stretch in the core, causing tension on the trunk and hip muscles. This stretch-shortening cycle is considered one of the most important elements in the generation of power and transfer of energy to the throwing arm and ball. - Relationship of pelvis and trunk kinematics to ball velocity in professional baseball pitchers.” (1)
Velocity Enhancement
Hip to shoulder separation is a key pitching velocity enhancement. The stretch shortening cycle assists in creating higher levels of trunk rotation velocity. Trunk rotation velocity is highly correlated to higher pitching velocity. Greater hip to shoulder separation allows for a larger rotation arc through which the trunk can build rotational velocity. The trunk accounts from anywhere between 50-80% of your velocity depending on the study. Hip to shoulder separation is the key biomechanics component to maximize the use of your trunk in the pitching delivery.
“Hip shoulder separation is related to trunk rotation velocity, and ultimately pitch velocity.” (7)
“High Velocity Pitchers rotate their upper trunk to a greater degree during the early phases of the pitching motion and subsequently generate greater trunk angular velocities and Pitching Velocity.” (8)
One study found that just by adding hip to shoulder separation in youth pitchers they increased their pitching velocity by 2-3 mph. (3)
“Adding separation of the hips and shoulders alone added an average 2.6 0.5 mph. The importance of hip and shoulder separation to pitch velocity relates to the ‘‘summation of speed’’ principle, that is, the greatest transfer of force occurs when the subsequent segment begins rotating at the moment at which the prior segment reaches maximal angular velocity; therefore, proximal trunk rotation ideally begins at the moment of maximal angular velocity of the pelvis, which explains the critical importance of the core musculature for high-velocity pitching.” (3)
Injury Prevention
Not only does hip to shoulder separation increase pitching velocity, but it is also very important for reducing your risk of injury. That’s right, you get the best of both worlds. One study found that professional pitchers put the least amount of rotational torque on their throwing arm compared to college and high school pitchers. Less torque on their arms despite throwing harder. They concluded this was because they, “rotated their trunks significantly later in the pitching cycle” (hip to shoulder separation) and this timing of their trunk rotation allowed for a more efficient transfer of energy through the trunk to the throwing arm.
“High rotational torques during baseball pitching are believed to be linked to most overuse injuries at the shoulder. This study investigated the effects of trunk rotation on shoulder rotational torques during pitching. A total of 38 pitchers from the professional, college, high school, and youth ranks were recruited for motion analysis. Professional pitchers demonstrated the least amount of rotational torque among skeletally mature players, while exhibiting the ability to rotate their trunks significantly later in the pitching cycle, as compared to other groups. It was concluded that the timing of their rotation was optimized as to allow the throwing shoulder to move with decreased joint loading by conserving the momentum generated by the trunk. These results suggest that a specific pattern in throwing can be utilized to increase the efficiency of the pitch, which would allow a player to improve performance with decreased risk of overuse injury.” - Effects of upper trunk rotation on shoulder joint torque among baseball pitchers of various levels. (2)
Summary
Hip to shoulder separation is the “X” factor in the pitching delivery. Elite high velocity pitchers are better at separating their pelvis and trunk than low velocity pitchers. Not only does it allow you to throw harder, but it also reduces your risk of injury. You need to be using biomechanics drills, strength and conditioning, movement and mobility work in your training to maximize this movement in your pitching delivery.
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References
Dowling, Brittany, et al. "Relationship of pelvis and trunk kinematics to ball velocity in professional baseball pitchers." 40th American Society of Biomechanics (ASB) annual meeting. 2016.
Aguinaldo, Arnel L., Janet Buttermore, and Henry Chambers. "Effects of upper trunk rotation on shoulder joint torque among baseball pitchers of various levels." Journal of Applied Biomechanics 23.1 (2007): 42-51.
Sgroi, Terrance, et al. "Predictors of throwing velocity in youth and adolescent pitchers." Journal of shoulder and elbow surgery 24.9 (2015): 1339-1345.
Nicol C, Avela J, Komi P. The stretch-shortening cycle: a model to study naturally occurring neuromuscular fatigue. Sports Med. 2006;36:977–99.
Flanagan EP, Comyns TM. The use of contact time and the reactive strength index to optimize fast stretch-shortening cycle training. Strength Cond J. 2008;30:32–8.
Komi PVP. Stretch-shortening cycle: a powerful model to study normal and fatigued muscle. J Biomech. 2000;33:1197–206.
Bullock, Garrett S., et al. "THE RELATIONSHIP OF RANGE OF MOTION, HIP SHOULDER SEPARATION, AND PITCHING KINEMATICS." International Journal of Sports Physical Therapy 15.6 (2020): 1119.
Luera, Micheal J., et al. "Differences in Rotational Kinetics and Kinematics for Professional Baseball Pitchers With Higher Versus Lower Pitch Velocities." Journal of Applied Biomechanics 36.2 (2020): 68-75.