Updated: May 5, 2022
Ulnar collateral ligament (UCL) reconstruction or repair, also known as Tommy John surgery, is a rising issue in baseball at all levels. I wrote about UCL reconstruction and repair here, but I want to discuss some staggering statistics. In Major League Baseball, 10% of professional players had undergone UCL reconstruction surgery in 2012. That number jumped to 13% in 2018 per Leland, et al. Another study by Rothermich, et al. showed that 2.5% of Division 1 college baseball players underwent UCL reconstruction in the prior year. That equates to 0.86 surgeries per program. So, a vast majority of programs had at least one Tommy John surgery in the prior year at the Division 1 college level. These are large numbers.
Baseball has come a long way over the last few years, but these studies looked at the 2017 and 2018 seasons. All of our information on training, workload, and other metrics should be limiting injuries. Instead, we are seeing an increase in injuries. Part of that can be due to players simply getting better. Players are throwing harder at younger ages which puts stress on the arm in ways we never saw before. However, it is irresponsible to ask players to throw with less velocity, as throwing harder is a surefire way to advance your career.
We have actually seen an overall decrease in shoulder injuries over the years, but elbow injuries continue to increase. Shoulder strengthening has come a long way, and most pitchers are doing some form of shoulder exercise, but few focus on their elbow. The elbow is supported by the biceps, triceps, and other muscles from above and the forearm muscles from below. It may be time to look more in-depth at strengthening protocols for those muscles, as they seem to play a role in elbow stability.
Before we dive too far into the rationale behind training the forearm musculature, it is important to understand the anatomy of the region. Here is an excellent image of the muscles surrounding the UCL courtesy of drahmadsportsmedicine.com
Notice how closely the UCL relates to the five muscles that are on the left side of the image? These are collectively known as your wrist flexors and pronators. They are responsible for bending your wrist towards your palm side, as well as rotating your palm down. This is a very important motion in throwing a baseball. Let’s take a look at each of these 5 muscles briefly:
Palmaris longus - This muscle is very small and absent in a portion of the population. It is also the muscle commonly harvested for UCL reconstruction surgery. It is minimally responsible for grip strength and is not a very important muscle, so we do not need to consider it here.
Flexor digitorum superficialis - This muscle helps flex our fingers (except for our thumb) as well as our wrist. It is one of the most important muscles that actually inserts into your fingers for bending.
Pronator teres - This muscle is slightly responsible for flexing your elbow, but its main purpose is pronation. Pronation is the motion of turning your palm downwards. The pronator teres actually only travels part of the way down the arm and does not reach the wrist. However, it is still important for UCL stability based on its location.
Flexor carpi radialis - This muscle flexes the wrist and creates some radial deviation. This refers to tilting your wrist towards your thumb and is not a crucial motion, but still important. This is one of the two most important muscles for flexing your wrist. It inserts into the bones of your second digit.
Flexor carpi ulnaris - This muscle flexes the wrist and creates ulnar deviation. This refers to tilting your wrist towards your pinky finger can can be somewhat important for throwing breaking pitches. This is the other most important muscle for flexing your wrist. It inserts into the bones of your pinky.
Now we have a basic understanding of the muscles surrounding the UCL and you can see their importance in wrist motion and elbow pronation. They are also important because they originate from the humerus, which is the bone of your upper arm. Imagine trying to bend your elbow to the side as shown below courtesy of physicaltherapyct.com
The primary resistance to this motion is your UCL, located on the inside of your elbow. However, those muscles that we previously discussed also cross along the joint space of your inner elbow, meaning they provide some resistance as well. Imagine doing this motion with your arm completely relaxed and then trying it again while making a fist as hard as you can. Engaging those muscles to make a fist creates significant active restraints to the gapping motion, providing support for the UCL.
Research using cadaver elbows showed that the UCL ruptured with a force of 34 Nm (Ahmad, et al.). This is important to note because research shows that pitching can exert forces of 40-120 Nm on the elbow (Van Tright, et al.). This means that something else must be supporting the elbow during pitching, otherwise everyone would tear their UCL as soon as they threw. It is thought that the forearm muscles provide much of that stability.
How to measure Grip Strength
If we know that the forearm muscles are important in preventing elbow stress, then how can we use that information practically? We first need to measure grip strength to get some sort of baseline. After all, if someone is three times as strong with their grip, that probably bodes well for their muscles providing support.
One strategy for measuring grip strength is to see how long you can hold a weight. You can choose a weight and hold it for as long as possible. This allows you to re-test yourself down the road and see if you have improved. Unfortunately, I believe that this is a flawed metric for baseball players. Baseball is a power-based sport, meaning that your effort comes in short bursts. Prolonged holding of a weight is testing endurance, which is probably not as important of a measure for baseball players.
Another option is testing your maximal grip strength. This involves using a piece of equipment known as a dynamometer. There are many versions of dynamometers, but this is one:
The machine will measure the maximal amount of force you used while squeezing as hard as possible. This provides an accurate measure for your grip strength, which I think is more closely aligned with baseball.
An interesting twist that you can put on measuring grip strength and eventually exercise is your use of your thumb. If you remember from the anatomy of the forearm muscles, none of them actually act on your thumb. Our thumbs are the most complicated finger and they have several muscles to control them, but none of them originate near the UCL. If you are testing your grip strength, perform the test as shown above then take a break to let your arm recover. After a minute or two, do the same test with your thumb resting on the side of the dynamometer so that it is not helping in any way. Your force may be lowered, but this is probably a more accurate metric of the muscles around your UCL.
How to train Grip Strength for Baseball Players
Now that we know how to assess grip strength, the next step is to train it. There are several options for training the forearm muscles.
The first option relates to the first assessment I proposed, where you hold a weight as long as possible. Exercises such as farmer’s carries involve holding a weight and walking for as long as you can tolerate. As I mentioned before, I think that this exercise enhances muscle endurance, so it is not optimal for protecting the UCL in baseball. I do think these exercises can be incorporated into a training program, but I do not think that they are the most important forearm exercises available.
Another option is to simply lift heavy weights. If you are familiar with powerlifters, you will see them deadlift with straps on their wrists and hands. These straps provide support because they are physically unable to hold the weight that they are lifting. They are training their backs and hips, so they do not want to use lighter weight, which would be necessary without straps. Most exercises only take a couple of seconds, which is a similar stimulus to a baseball pitch. If you are able to deadlift heavy weights, then you are working the forearm muscles rapidly with significant load. Unfortunately, some people are not strong enough to work their forearms appropriately, and you are limited in the amount of times you can lift heavy weights due to fatigue and workload.
Isolated forearm exercises are another possibility. Wrist curls with dumbbells have been around for a long time because they are effective. You are only training your forearm muscles, so you can use as much weight as they can handle. This mistake I often see with these exercises is that people will not use enough weight and will perform 15-20 repetitions with mini