Strength in Numbers #192
Vertical jump testing is a widely recognized measure of lower-body power and overall athleticism. While commonly associated with sports like basketball and volleyball, recent research has explored its relevance to baseball pitchers, particularly concerning throwing velocity and potential injury risks.
At Louisiana Tech, we have a baseball science undertaking that is growing in knowledge about how the physical body and the process metrics in training influence statistical performance. Now, we are looking at health—what physical and competitive features drive up the load and potentially drive down throwing arm strength?
Research has confirmed that absolute vertical jump power increases velocity, but can a bigger engine cause more damage to the arm?
What happens if we put in more horsepower and our braking system is not matched up?
What happens if we become too explosive to sustain the rate of force applied from the ground, which is then absorbed and transferred up the chain until we reach the throwing arm?
If you are working to improve your vertical jump, read this article to ensure your safety on the bump.
More Vertical = More Velocity? The Hidden Risks for Pitchers
Several studies have investigated the correlation between lower-body power, as assessed by vertical jump performance and pitching velocity in baseball. The underlying premise is that a pitcher’s ability to generate force from the lower body contributes significantly to the kinetic chain, ultimately influencing the speed of the pitch. Enhanced lower-body strength and power can lead to more effective energy transfer through the torso and upper extremities, culminating in higher throwing velocities.
Our Velocity Program Monitoring and Adjustments Course discusses factors that truly help promote velocity enhancement. When it comes to the vertical jump, improving it will give young athletes velocity gains. In contrast, older athletes will lose velocity if they do not maintain their stretch-shortening abilities.
Up until 22 years old, the point where our elasticity tends to decline, it is a good rule of thumb to be able to jump 1.5x your age so that you set the lower body power goal appropriately for jump height in inches that will translate to a greater intersection of force, lean mass, and jumping velocity. Yup, exploding off the ground requires all three factors, and we can measure jump metrics using a force plate.
Like a pitching coach tracks ball flight characteristics, force plates provide deep insights into how the center mass loads and explodes based on how the lower limbs interact with force plates beneath the feet. The information tells us about the neuromuscular performance of the lower limbs and helps shape training interventions.
Here are some of the key force plate measures that are captured with each jump:
- Concentric Impulse: This represents the total force multiplied by the time the force is applied during the jump’s upward (concentric) phase, influencing jump height.
- Peak Force: The maximum force generated during the jump indicates an athlete’s maximal strength capacity.
- Rate of Force Development (RFD): Measures how quickly force is produced, reflecting explosive strength.
- Eccentric Rate of Force Development: The speed at which force is generated during the downward (eccentric) phase, crucial for effective energy storage and subsequent force production. We see the end of the eccentric phase when the athlete stops at the bottom of the vertical jump.
- Reactive Strength Index-Modified (RSI-mod): Calculated by dividing jump height by the time taken to achieve take-off (contraction time), RSI-mod evaluates an athlete’s explosive capabilities or twitchiness in getting high off the ground in the least amount of time
- Absolute Power: This measure is in watts, the rate of work or the force produced by the athlete multiplied by the velocity of take-off. Some formulas, like the Sayers formula, estimate vertical jump power from jump height and body mass. Ultimately, we want athletes to increase their lean mass and jumping ability to boost velocity.
The video below explains why absolute jump power is essential in raising fastball velocity. At the time, we did not understand the risks associated with raising horsepower without harnessing arm strength.
Vertical Jump Testing and Elbow Injury Risk
While the direct relationship between vertical jump performance and elbow injuries in pitchers has not been extensively documented, research looking at concentric impulse (the time application of force), eccentric rate of force development (how quickly athletes apply deceleration force), and average vertical jump force has been shown to associate with UCL surgery risk.
No clear mechanism of injury was identified, which inspired our work at Louisiana Tech to evaluate what’s going on at the elbow three-dimensionally when pitching in relation to jump performance.
There is a broader context linking lower-body mechanics to upper-extremity health. Pitchers who lack adequate lower-body strength and power may compensate by overusing their arm and shoulder muscles, increasing the risk of overuse injuries, including those to the elbow. I have personally researched what happens to forearm muscle function when pitchers lose lower-body power.
Now, the question is, what happens when the athlete sees a surge in lower body power?
That’s where I am sharing our research that is hot off the press.
Jump Power is Correlated with Rate of Torque Development for Elbow Varus Torque
We have lived in a world where we believe that maximum elbow torque is evil and that jumping to the moon is what we want to get our athletes to throw at maximum velocity. The reality is that as velocity increases, jump power increases, and as jump power increases, maximum elbow torque to resist stress on the UCL may not elevate. Still, the rate of torque imparted on inner elbow muscles and the UCL increases.
In a nutshell, greater lower body power elevates the loading speed on the inner elbow, and with bigger jump gains comes a greater responsibility to monitor athletes with the ArmCare.com platform and protect them from injury.
Another way to think about this is if your arm is a touring vehicle like an Escalade, adding a little rocket fuel by gaining lean mass and jumping higher and faster off the ground can turn the elbow into a Ferrari and raise torque from 0 to 60 in less time. Arm strength monitoring has been primarily a focus for players and baseball coaches. Still, this data is critical for strength coaches and therapists who actively prescribe training to build a bigger engine.
Understanding this connection, assessing and enhancing lower-body power through vertical jump testing can be integral to a comprehensive injury prevention strategy. However, it cannot operate in isolation from evaluating the throwing arm function.
Implications for Advancing Vertical Jump Power While Preventing Arm Injuries
Incorporating both vertical jump and throwing arm assessments into a pitcher’s training regimen offers several benefits:
- Performance Enhancement: Improving lower-body power can increase pitching velocity, as a strong foundation allows for more efficient force transfer throughout the pitching motion. If throwing velocity rises and the strength velocity ratio decreases, we have issues, as the athlete’s engine is more powerful, while the contractile performance of the arm is not adequate, which means stretching of passive tissues, like the UCL. With lower body power translating to velocity enhancement, high-speed loading of the inner elbow can occur.
- Injury Prevention: By bolstering lower-body strength, pitchers can reduce undue stress on the shoulder and elbow, potentially decreasing the likelihood of overuse injuries. This one is a double-edged sword. If we know that increased lower body power can increase the rate of loading on the UCL, it can be problematic for the risk of injury. However, if we do not optimize lower body power, reducing stride length can put an athlete at risk as it can significantly increase forearm muscle fatigue.
Conclusion
Vertical jump performance is a valuable indicator of lower-body power, crucial for a baseball pitcher’s throwing velocity and mechanical consistency.
While previous research shows how the elbow muscles can fatigue at a greater rate with reduced ground reaction force, current research shows us that we need to monitor athletes’ throwing arms who see increased lower body power, especially in a short period.
No question, it feels amazing to dunk a basketball and throw cheese, but with all that jet fuel and no parachute, you are asking for way more bump from your jump. So make sure your arm is ready for take-off and raise your Strength-Velocity Ratio and ArmScore!
Get up there but be aware….and as I always say….
STRENGTH MATTERS MOST,
Ryan
Ryan@armcare.com
