Improving an athlete’s Rate of Force Development is like striking gold for baseball players because it directly impacts key actions like hitting, throwing, and sprinting.

What is RFD?

RFD is defined as the speed at which the contractile elements of the muscle can develop force. Higher RFDs have been directly linked with better time to peak power (TTPP), which is pure gold for improving efficiency in jumping, sprinting and throwing in other words, all things baseball.

Time to Peak Power (TTPP)

TTPP is a metric that measures the time it takes for an athlete to reach peak power output during a concentric (lifting) phase of an exercise or sport movement. It helps coaches and athletes understand how quickly force is produced and can be used to optimize training for explosive movements and power development.

A shorter TTPP generally indicates faster force production which we generally measure using VALD force plates.

Why are RFD and TTPP important?

In an explosive sport such as baseball, where the average time it takes to go from foot plant to ball release is anywhere between .150 – .250 s, acceleration is king. A quicker TTPP translates into more ground reaction forces (GRF) being transferred from foot plant to both ball release (pitching) as well as exit velocity and / or bat speed (hitting). It also contributes to a more stable base of support, enhancing a player’s overall mechanics as well as faster speed and ultimately better performance on the field with less chance of injury.

Testing… How Do We Assess It

The equation for power is:

>> Force * Velocity <<

Force = Mass * Acceleration thus the total equation for power is:

>> Mass * Accel * Velocity <<

It’s first important to note that nothing happens in isolation, and to ultimately improve the TTPP, we have to utilize all three of these training adaptations from the power equation above.

The problem is every athlete relies on different parts of the equation more than others. For example, some athletes rely more on the force / accel side of the equation (strength) while others may rely more on the velocity / side (elasticity and plyometric ability). As a result, we need to assess each athlete’s strength and elasticity (they’re ability to utilize their SSC), as well as their baseline ability to produce force quickly. We can then give them more of what they are deficient in, without taking away what they are already good at.

We perform 3 tests utilizing VALD force plates to calculate:

1. How well do they use their stretch-shortening cycle, as in how elastic are they?
2. How much force do they currently apply quickly?
3. Where on the Force / Velocity curve does the player lie? Force (strength) or Velocity (elasticity)?

I won’t be going into the testing so much in this article, but here is a brief description of the 3 testing protocols we use during our assessment:

1. EUR Test (for Elasticity) – Testing for elasticity gives us an idea of how well the athlete uses their stretch-shortening cycle (SSC). A higher score generally relates to a more velocity-based athlete. We perform two types of jumps, and compare the % difference by dividing the CMJ and Squat jump.

2. Concentric RFD @ 200 ms – Though there are multiple ways to measure the rate of force development, the time-interval sampling windows appear to be the most reliable.

It’s always best to take the RFD between 2 set time periods specific to the sport. For baseball, this is generally between .150 – .250 s (foot plant to ball release/contact).

We use a “Squat Jump in our testing protocol to avoid any eccentric movement that may skew the concentric result we are testing for. VALD allows us to set a pre-set time to calculate force, which we set to .200 s due to the specificity in the variables of pitching and hitting explained prior.

Squat jump with VALD

3. Dynamic Strength Index (DSI) – This test calculates peak force output between a strength-based exercise (iso-belt squat, and a velocity-based exercise (CMJ Jump). The results tell us a lot about which side of the equation our athlete relies more on, so we can then focus his programming on the other. For example an athlete that performs better on the iso-squat is more force -based and needs to focus more on velocity-based training in his program or vice-versa.

CMJ Jump

Iso Belt Squat

Training the Power Formula (Mass * Accel * Velocity)

A. Mass

This portion of the power equation is trained primarily through Max Strength and trains primarily force production. This involves strength training with the appropriate loads (75-90% 1RM) for reps of 3-8. We can also use what is known as accommodating resistance by using chains. By de-loading the bottom of the movement with chains, we are removing the limiting factor and utilizing more starting strength / acceleration from the bottom (start of each rep), allowing for quicker RFD and ultimately TTPP.

Bench Press w/ Chains

For more info on training force please click here.

B. Acceleration / Elasticity

Elasticity is the body’s ability to store and release elastic energy from connective tissues, namely the tendons. By building more elastic / “springy-ier” athletes, we begin to transition the reliance away from muscular-driven movement and more towards a reliance on the power of connective tissue. In other words, more force / power with less effort.

While it is trained through various methods, a two of my favorite are:

- Extensive Plyometric Exercises (focus on quick ground contact times) – These exercises focus on quick and powerful jumps and bounds, helping athletes rapidly transition from eccentric to concentric contractions, resulting in increased explosiveness.
- Med Ball Training – There are not many upper body methods that can generate force in the frontal and transverse plane better than med ball drills. (unless you have a Proteus motion machine). The rapid, forceful movements involved in medicine ball training can directly improve the velocity of throws, jumps, and other movements- all crucial for developing power.

Leg Lateral Line Hop

Med Ball Shovel Pass

For more info on training Acceleration / Elasticity please click here.

C. Velocity (Low Load Power)

Utilizing lower loads (20-30% 1RM) are effective for training velocity because they utilize heavier loads than traditional jump squats and allow for a more explosive, powerful movement with a focus on rate of force development. We like to use trap bar jumps because they help promote a more upright posture and reduced spinal stress.

Trap Bar Jumps 20% 1RM

Summary

By thoroughly assessing your athletes consistently and incorporating these methods into their routines, baseball players can improve their rate of developing force and ultimately their ability to generate power faster. The use of force plates such as the one we use from VALD help us pinpoint metrics and training to an even more granular level, giving our athletes what we believe to be a significant advantage both on the field and behind the plate.

By Nunzio Signore (BA, CSCS, CPT, NASM, FMS)

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