Strength in Numbers #190
The early season is the danger zone for ulnar collateral ligament (UCL) sprains—the injury that leads to Tommy John Surgery.
Therefore, the critical time is now.
To follow up on our recent article about skyrocketing Tommy John Surgery cases, this week’s newsletter takes a deeper dive into the science of four Fs: finger flexion force fatigue.
In summary, the UCL bears the brunt of the stress of pitching, when the surrounding muscles are not strong enough to protect it.
There are endless theories about why TJ surgeries are at an all-time high, but few people are looking deep enough into the research to find real solutions.
Let’s change that!
Discover how understanding and addressing 4Fs can be a game-changer for arm health.
Not All Pitchers Overstress Their UCL
A recent article indicated that pitchers with higher elbow torques (and higher throwing velocities) had lowered middle finger pinch strength, indicating less effective medial elbow stabilizing strength by the flexor digitorum superficialis, a key stabilizer of the UCL.
Within an individual, higher throwing velocities are typically associated with greater medial elbow torque, which is force that puts load on the UCL.
Research done at ASMI showed an approximate relationship: every 1 MPH increase is roughly equal to 1 unit of torque increase within a pitcher.
Although, ironically, comparing pitchers, there is NO association between velocity and medial elbow torque. That means two pitchers who throw 100 mph could have completely different forces on the elbow.
Of course, we don’t have a crystal ball, but with the ArmCare.com platform, you can measure strength and determine how athletes fatigue, and in connection with previous studies, this is a good predictor of an increased risk for injury.
When we see declines in strength and function, this warrants programming adjustment.
Testing Grip Strength Is NOT Enough
It’s an easy generalization to say the forearm muscles protect the UCL from damage. However, the research doesn’t fully support testing full handgrip strength to predict injury risk.
One article does show that full handgrip strength declines with altered biomechanics, but overall, grip strength is not as sensitive as testing the finger strength.
In another study on 213 pitchers, hand grip strength did not differentiate between injured and non-injured pitchers, which further validates the importance of testing finger flexor strength.
Then, in a study investigating strength losses in dynamic elbow stabilizers, full handgrip was not different between pitchers with high and low medial elbow torques and it was not sensitive to pitch counts.
The problem with using full hand-grip testing is that it’s not sensitive enough to pick up on the specific strength of the muscles that protect the UCL.
One confounding variable associated with full handgrip testing is how muscle irradiation can mask the true strength of the forearm. The influence of maximal contraction of shortened and contracted muscles away from the forearm can raise its strength under a state of fatigue.
Additionally, by using handgrip dynamometers, athletes can also provide extra neural drive to the forearm by contracting the triceps, lats, glutes, quads, and other muscles that could artificially raise the actual strength of the dynamic stabilizers of the forearm.
Based on the research and the issues addresses above, testing specific finger-flexion function is a better means to determine fatigue and the potential for UCL injury.
THE FLEXOR DIGITORUM SUPERFICIALIS (FDS) TEST TO REDUCE TJ SURGERY RISK.
A recent article indicated that pitchers with higher elbow torques (and higher throwing velocities) had lowered middle finger pinch strength, indicating less effective medial elbow stabilizing strength by the flexor digitorum superficialis, a key stabilizer of the UCL.
The flexor digitorum superficialis (FDS) is the forearm muscle that has been shown to contribute most to medial elbow stability since it’s situated directly over the UCL.
Therefore, we need to focus on testing the strength of this muscle group to evaluate fatigue and individualize throwing programs and training to reduce the risk of Tommy John Surgery.
The FDS TEST TO REDUCE TJ SURGERY RISK.
ArmCare’s protocol for assessing forearm finger force fatigue includes the following:
- Three-Finger Baseball Grip: Near maximal external shoulder rotation, the flexor digitorum superficialis (FDS), and other flexor pronator mass muscles contract to protect the UCL and shield it from tensile overload that causes excessive strain. Since the device is gripped like a baseball, it targets the forearm strength potential in a similar fashion to how the finger flexors are activated in delivering a throw. This is a more representative test feature than other forms of forearm strength evaluation.
- Half Kneeling Position: This knocks out the legs and therefore the glutes, quads and hamstrings are not able to contract maximally during the test to artificially amp up FDS contraction.
- 90-90 Arm Position: The arm is in a provocative position that may indicate potential blood flow reduction to the forearm that has been seen in previous research. Additionally, this position reduces activation of the lats, pecs, biceps and triceps, and therefore, FDS strength changes in this position are more sensitive to diagnose fatigue and could signify a neurovascular problem.
This video is from our new ArmCare Specialist Course that explains how to properly perform ArmCare’s baseball grip strength test to determine finger flexor force fatigue.
In part two of this series, we are going to lay out situations, examples, and an integration plan on how to assess finger flexor strength throughout the training and competitive season and what signals you have to watch out for as it relates to minimizing risk and the frequency of Tommy John Surgeries performed each year.
Know your 4Fs!
Ryan
Ryan@armcare.com
