Returning to Baseball After ACL Reconstruction

It is no secret that anterior cruciate ligament (ACL) injuries and reconstruction surgeries are very common at all levels of sports today. As a physical therapist, I rarely go more than a few days without a patient in my clinic rehabilitating from ACL reconstruction (ACLR), and many coaches have likely encountered or will encounter athletes returning from this surgery.

Though ACL injuries are infrequent in the sport of baseball, I have helped several baseball players rehab and return to play after ACLR over the past year. While most baseball coaches likely have some awareness of shoulder/elbow injuries, they may not have as much exposure or education with players returning from ACLR.

For the rehab professional, it can also be very easy to overlook the sport-specific demands of baseball players when rehabbing from ACLR.

My purpose in writing this article is to provide some insight into recent research regarding return to sport after ACLR and some points to consider when returning to baseball activities after ACLR.


Secondary ACL Injury Risk – The Research

One of the biggest issues with returning an athlete to sport after ACLR is risk of a secondary ACL injury, either in the same knee or on the opposite knee. New research indicates that this may be happening at an alarming rate.

I will list some statistics below and then will discuss why these findings matter and how we can improve on how we are returning these athletes to sport activities.

  • A 2016 study reported approximately 1.25% of high school and college athletes will have an ACL injury.
  • 6 different studies looked at athletes returning to sport after ACLR, and the average rate of a 2nd ACL injury in these studies was roughly 30% (ranging from 25-37%)!
  • In one study, 45% of re-injuries occurred in the first 2 months after returning to sport
  • Those who returned to sport within 5 months after surgery had a re-injury rate of 100%
  • Those who returned within 9 months had a 40% re-injury rate
  • Those who waited until after 9 months had a 19% re-injury rate
  • There is a roughly 50% decrease in re-injury risk for each month that return to sport is delayed up to 9 months post-op.

Remember that there are always a number of factors involved with any injury, and these include age, gender, sport(s) played, time of year, common playing surface, genetics, previous training history, previous injury history, and many more. Even without specific context, these numbers above are very alarming, and this has become a hot topic issue in the world of sports rehabilitation.

It has become common for surgeons to release athletes to return to sport activities at 6 months post-op, despite the statistics listed above. It has been a challenge for me to convince patients to avoid early return to sport when their surgeon has given them clearance, especially when strength limitations, mobility limitations, movement deficiencies, or any of the factors listed above are still present.

So the challenge, then, is how do we get better in minimizing risk for re-injury with these athletes?


Reducing Risk for Secondary ACL Injury


First, delaying return to sport is usually a great place to start. While there may be certain pressures influencing an athlete to return by a given time, much of the research listed above speaks against simply using a given time frame to determine when an athlete should return.

Many experts are now recommending waiting at least 9 months before returning to sport, with increased time often needed depending on the status of the athlete. The short-term benefits of early return often do not outweigh the long-term risk of re-injury. It is now generally accepted that there should be specific criteria met before returning, regardless of when that is achieved. What specific criteria should be used to determine when an athlete should return to sport is a topic that deserves a separate article of its own.

One of the primary reasons why I believe we see relatively high re-injury rates is that there is often poor communication between the rehab professional and the coach who inherits the athlete who may or may not be completely ready for full return to sport. Often times there are insurance limitations at play or the rehab professional discharges the athlete early with the assumption that the athlete will continue to be compliant with a home exercise program.

As a result, athletes are often discharged from formal physical therapy before they are ready for full return to sport. This leaves them with a lack of professional oversight of their rehab program if they are unable to work with an athletic trainer in their school. Many athletes, then, either do not stay compliant with their home exercise program or are not provided with proper progression of exercises, and their home program eventually fails them.

Research has shown that movement quality can decrease within a few months of stopping supervised exercise programs in uninjured youth athletes, and we have to assume the same is true in a rehabilitation population. Ultimately, unsupervised and outdated exercise programs are not adequate in getting athletes to perform at the required level to return safely to sport.

I believe part of the solution to this problem is to have greater communication between the rehab professional and either the player’s coach and/or parent to ensure that somebody is able to supervise the athlete with their exercise program.

As a coach, if you have an athlete returning from an injury, it is crucial that you get in contact with the athlete’s medical professional to ensure that you are safely and gradually returning that athlete to play. Employing or partnering with a knowledgeable strength and conditioning coach or rehab professional can be a great way to ensure that your athletes are maximizing their development and being monitored for red flags with regard to future injury risk.


Return to Baseball-Specific Activities


One of the areas in which professional supervision may be most important is when handling return to baseball-specific activities such as throwing and hitting. It is important to remember that the athlete has likely spent an extended time away from these activities.

For many athletes, this is likely a good thing for upper extremity health and provides a great window to address issues in the upper extremity kinetic chain. As a rehab professional, it is important to ensure that proper trunk and upper extremity strength and mobility are achieved and maintained, even in the early stages of rehabilitation. This will ensure that the athlete is ready for a gradual progression of throwing activities once their knee allows them.

Once the lower body is ready for returning to throwing or hitting, it is important to allow for a gradual ramp-up in volume and intensity of these activities. Excessive early volume or intensity may predispose them to injury in other areas of the body, such as the shoulder or elbow.

For a recent athlete of mine, we spent an extended period of time performing plyoball throwing drills followed by light flat ground throwing before he got anywhere near the mound just to ensure that he was able to build tolerance for throwing again. This also allowed for gradual progression of loading his surgical knee prior to performing high intensity throwing on a mound. As a coach, you cannot assume that the athlete is ready to return to max effort throwing activities just because the knee appears to be ready for it.

On that same note, specific drill work is a great way to introduce the athlete to baseball activities, but they should be performed with gradual progression of intensity and difficulty. This can allow a player to begin to feel comfortable with position-specific activities before their full return to play. Again, this is where input from an informed professional can be an excellent way to ensure that you are maximizing what you can do with the athlete without exposing them to unnecessary risk.

This is also an excellent time to assess how other parts of the kinetic chain may be impacting throwing or hitting mechanics. Athletes with ACL injury are likely to display limitations with ankle mobility, hip mobility, lower extremity strength, and possibly even trunk stability or mobility issues if these have not been areas of focus throughout their rehab process. While these areas may have been deemed adequate to perform basic strengthening exercises or running/plyometric progressions, they may provide barriers to adequate performance with throwing or hitting.


Closing Thoughts

While there is a relatively large amount of research in return to sport after ACL reconstruction, I am unaware of any that relates specifically to baseball players. I hope to see future research investigating short-term or long-term changes in throwing or hitting mechanics in athletes with previous ACLR history.

These topics discussed above are only a small number of issues that need to be taken into account when returning athletes to baseball after ACLR surgery and there are numerous others that could be discussed as well.

While I work full-time in an outpatient physical therapy clinic, I have made it my goal to partner with local programs and facilities to try to assist with topics such as this to ensure that athletes, coaches, and parents can be better educated about how to safely and effectively return to baseball activities while minimizing risk for future injuries.

For any coaches or facility owners who may read this, I encourage you to partner with a rehab professional or knowledgeable strength and conditioning professional to ensure that you are promoting proper health and wellbeing of your players.



Stanley, et al. Sex differences in the incidence of anterior cruciate ligament, medial collateral ligament, and meniscal injuries in collegiate and high school sports: 2009-2010 through 2013-2014. Am J Sports Med, 2016 Jun;44(6):1565-72. doi: 10.1177/0363546516630927.

Grindem, et al. Simple decision rules can reduce reinjury risk by 84% after ACL reconstruction: the Delaware-Oslo ACL cohort study. Br J Sports Med, 2016 Jul;50(13):804-8. doi: 10.1136/bjsports-2016-096031.

Goerger BM, et al. Anterior cruciate ligament injury alters preinjury lower extremity biomechanics in the injured and uninjured leg: the JUMP-ACL study. Br J Sports Med, 2015 Feb;49(3):188-95. doi: 10.1136/bjsports-2013-092982.

Sugimoto, et al. Compliance with neuromuscular training and anterior cruciate ligament injury risk reduction in female athletes: a meta-analysis. J Athl Train, 2012 Nov-Dec;47(6):714-23. doi: 10.4085/1062-6050-47.6.10.

Padua DA, et al. Retention of movement pattern changes after a lower extremity injury prevention program is affected by program duration. Am J Sports Med. 2012;40:300–306. doi: 10.1177/0363546511425474.

The Three Hardest Challenges of Tommy John Rehab

My elbow hurts a lot.

My arm feels really tight.

I feel great!

It was really sore the next day.

I had nothing on it – no movement and no velocity.

It started off good, then it started to hurt.

The ball was really coming out well, no pain at all!

It just feels…dead.

If you’re a pitcher who’s gone through Tommy John surgery, you’ve probably uttered all the statements above. If you’re a rehab professional, coach or parent, you’ve probably heard them too as the pitcher(s) in your life finished up their latest throwing session.

As a coach who had two Tommy John surgeries, I know that the hardest part of both of my rehabs – and they were both hard for the same reasons – was the randomness with which the arm recovers and the mental toll it takes on you. Today as a coach, I mentor young pitchers through their own recoveries and hear the same difficulties voiced regularly. Today, we’ll discuss the mental challenges of the surgery in its various forms.


First: Why The Last Part of Tommy John Recovery Is The Hardest

After about month eight or nine of the recovery the pitcher is capable of doing a lot of new things that make his arm hurt, get sore, and react in new and confusing ways. The player is also pretty much done with the formal, written throwing protocol, so months 9+ end up being up to interpretation, much like one of those make-your-own-adventure books. This is because pitchers in this last phase are:

  • Throwing nearly at or just near full-speed
  • Throwing off-speed stuff again
  • Increasing frequency of bullpens
  • Beginning simulated games against live hitters
  • Getting physically stronger and doing more demanding lifts in the weight room
  • Feeling the pull that they are almost ready

Because of this, the body is getting huge doses of new things ­­– it’s not just soft-tossing grenades anymore, the pitcher is putting the same forces through his arm that tore it in the first place. He’s mixing all his pitches, and curves, sliders and changeups all make the healing ligament react and get sore.



Workouts in the weight room are crucial to returning him to game shape and warding off future injury, but as strength returns, heavier weights cause the elbow to react and get sore, sometimes painful as well. How does a pitcher balance all these things?

This question raises many, many more questions:

How much should he lift after a hard bullpen that caused a little pain? Should some exercises be omitted, altered, or used with lesser resistance?

Should bullpen pitch count increase? If so, how much?

Should rest between pens begin to decrease? If so, how much?

How much should a pitcher throw in between bullpens?

Is long-toss okay? If so, when?

Are weighted balls appropriate? If so, when?

When can a pitcher return to a game?

When can he pitch on back-to-back days in relief?

His arm hurts a LOT – is that normal? Is it torn again? How long should I wait to throw?


The common answer to all the above is this: it depends. It’s a very unsettling answer.

There are a million variables that can’t be addressed in the written throwing protocol. There’s just too much variation and too much throttling up and down to account for it all. The experience is similar for players but also completely and painfully unique.

If the questions above seemed confusing…imagine you’re a 19 year-old kid going through this for the first time – it’s a lot.


Challenge #1: Interpreting and Coping with Types of Discomfort

There are four main feelings a pitcher will experience in his recovery:

  • Pain: that sharp, stabbing feeling.
  • Soreness: that dull, burning feeling.
  • Tightness: When the arm feels constricted and doesn’t move like normal, as if the joint is swollen or needs to “pop.”
  • Deadness: a general dull, achy, fatigued feeling in which the arm just…can’t.

Which of these is worse? Pain gets a pitcher’s attention the fastest, but all are unique. Soreness often turns to pain. Tightness turns to any of them and makes throwing very uncomfortable. Deadness is demoralizing.

Some of the best advice I ever received was from Stan Conte, former head ATC of the Los Angeles Dodgers. He basically just reminded me that my arm had holes drilled in it, and that the muscles and ligaments were sliced open before being stitched back together. He explained that it would never be “normal” again, and that weird pain, sensations and unexplainable things would happen. I just had to learn to accept some of that.

When I thought of it that way, I stopped dwelling on slight pain and the little aches and soreness – those were just from my arm being, well, a lot like an old car. Old cars make lots of weird sounds and are a little bumpier, but they still drive just fine.

Pitchers who have had a surgery – any surgery – are never going to feel fresh off the assembly-line again. When they stop believing they have to feel perfect and brand new to pitch, things mentally get a lot better.


Challenge #2: Dealing With The Randomness of Pain 


What’s extra frustrating about the recovery is that there is little reason why one day is a good day and why another day is a bad day.

Sure, when a player overdoes it or does something new, the arm usually reacts in a negative – but still normal – way. However, lots of times a player will be adequately rested and has set himself up for success in his routine…just to find lots of pain and discomfort that doesn’t add up.

This – unfortunately – is also normal. It’s especially frustrating and worrisome because a player feels helpless to prevent or predict good and bad days. The follow exchange was had between myself and one of my college pitcher clients, who I have been mentoring through the last stages of his rehab in conjunction with his school coaches. It sums this point up perfectly.



Challenge #3: Expectations That Are Set Too High

Lastly, there’s this idea that every player should be back on the mound, dominating and throwing 2-5mph harder at the 12-month mark. This just isn’t reality for most pitchers. Most pitchers will feel like their old selves again somewhere between the 14 month and 24-month mark. Even when a pitcher is back in games, he often won’t reach his previous level of statistical performance until the second competitive year back…if he does so at all.

I doggy-paddled through my first season back following each surgery, struggling to keep my head above water and not get released by the team. I posted league-average ERAs in both seasons and could not locate my off-speed stuff to save my life. I got by with good velocity and a fierce will to compete. Had I not had both of those things, my career would have ended; I would not have had enough tools to get by in pro baseball.

But in year two following both surgeries, my command of all three pitches improved dramatically, and my velocity went up another tick or two. Year two was much, much better than year one. Year one was hard.


Tommy John Surgery: It’s a Long, Hard Road.

A lot of people take for granted just how hard it is to return from Tommy John Surgery; it’s not a guarantee for any pitcher, and the mental toll is often greater than the physical. The uncertainty, randomness, pain and daily grind will challenge even the toughest of athletes. The big challenge is staying the course and trusting that tomorrow will be better…even when today wasn’t.


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Does Electrical Stimulation Speed Recovery in Baseball Players?

***Disclaimer – placing electrodes on a player (or yourself) does not come without potential risks. The potential for electrical burns and infection are a real thing that warrant, at least in our opinion, the consultation of a professional.


In recent years, there has been a major increase in the usage of EMS (electrical muscle stimulation) units in the baseball world. From the MLB to the high school ranks, it seems like everyone has jumped on the “ESTIM unit” bandwagon, claiming that their inclusion has dramatically improved their performance. Supporters often cite improved blood flow, delayed onset muscle soreness (DOMS), and a quicker return to performance as the key benefits.


How Do EMS Units Work?

EMS units work by delivering electrical pulses through multiple electrodes, which are positioned over muscle motor points or painful areas. Depending on the frequency, intensity and waveform, the target of the stimulation is either at the sensory level (lower intensity) or the muscular level (higher intensity).

The units that are important here are what most people see on social media – the ones that elicit a muscular contraction to improve peripheral fluid flow in the body. The rationale being enhanced peripheral blood flow will accelerate the removal of metabolic waste, decrease inflammation, and promote a quicker return to a player’s performance baseline. In short, it speeds the recovery process after a tough game.



What Does The Research Say About The Effectiveness of EMS Units?

Professor Nicola Maffiuletti, a leading expert on the recovery process, gave a tremendous lecture for Aspetar Sports Medicine in 2013 on EMS based on a literature review that he co-authored.

In his presentation, Maffiuletti reviewed the available research on these units, their potential mechanisms, effectiveness and practical application. Here are some of the major takeaways.

  • Only 3 of 19 studies showed that EMS was more effective than passive recovery in regards to the return of muscle strength, power, activation and contractility.
  • All the other studies were unable to detect a difference between the two in healthy active individuals, recreational sportsmen and professional athletes. EMS was found to be equally effective compared to other modalities in all but one study.
  • Voluntary contractions may be better than EMS at increasing bloodflow because people are able to contract a greater amount of muscle manually. Recruitment via EMS—even at a very high visual analogue score (how much pain you can tolerate) —can only recruit around 15% of the muscle cross-sectional area. If you have ever tried ramping up the intensity on these units, you understand that it can get pretty uncomfortable and sometimes even painful! Of that 15%, it is mostly superficial muscle fibers that are recruited. To recruit deeper fibers and increase that percentage, you would have to increase the intensity of the stimulation. This can only feasibly be accomplished by improving an individual’s tolerance via persistent exposure; something that is difficult to accomplish.
  • However, according to Maffiuletti, using higher intensities can actually create muscle fatigue: “If you increase the intensity, you are creating fatigue that is 5 times faster than a voluntary contraction.”
  • There have been many case reports of muscular dysfunction resulting from overusing EMS units. If we overuse these devices we run the potential of creating long-term issues in how the muscle fires.
  • Lactate removal is faster with active recovery than it is with EMS.
  • Perceptual recovery – defined in the studies as the point when subjective psychomotivational factors were fully restored to pre-exercise levels. Subjects were asked to quantify or rank the perceived effectiveness of recovery modalities or quantifying their perceived energy and enthusiasm. EMS has been shown to be equally or more perceptually effective as a means of recovery than passive or active recovery

Maffiuletti concluded that EMS is unlikely beneficial for improving physiological recovery compared to both passive rest (including a placebo condition in one study) and other recovery modalities. EMS is, however, likely beneficial for improving perceptual recovery compared to passive rest, and possibly beneficial for improving perceptual recovery compared to other recovery interventions.


STUDY: Effects of Three Recovery Protocols on Range of Motion, Heart Rate, Rating of Perceived Exertion, and Blood Lactate in Baseball Pitchers During a Simulation Game.

There is, however, one often cited study in the baseball community by Warren et al. that looked at three different modalities and their effect on a pitcher’s recovery in-between innings. The authors found that a Compex Unit (EMS product) improved blood lactate removal significantly while active and passive recovery did not. Moreover, the Compex group, as well as the active recovery group, reported a significantly lower rate of perceived exertion.

Removal of lactate, however, is a naturally occurring process that can take minutes to an hour or two depending on the specifics of the exercise. Lactate removal has not been a good indicator of recovery outside of those timelines. If we know that lactate and metabolite removal is mostly completed within an hour post exercise should it really be the target of any of our interventions? Using EMS in-between innings to reduce lactate concentration may have some merit to it, but we probably need more research before we start making drastic changes.


Should Baseball Players Use EMS?

There is a general lack of evidence to support the idea that EMS improves physiological recovery and return of strength or power compared to other recovery modalities (passive, rest, or otherwise).

If our goal is to improve circulation of blood and fluid flow through a muscle contraction, then EMS seems to be less effective than alternative methods in which voluntary contractions are used. Moreover, if used inappropriately – with too much frequency and intensity – EMS may cause more harm than good.

These units are, however, potentially useful in promoting perceptual recovery, a placebo effect in which the player believes he feels strong and ready to play than perhaps he really is. In the baseball world, this may be a significant factor in returning to baseline performance. If an athlete perceives that he is more prepared to throw because of the twenty minutes of stimulation, then this may warrant its inclusion from time to time. EMS units, however, can be very expensive and it’s important to consider whether a device that provides only perceived benefits is a good use of financial resources.

Do you use EMS? Leave us a comment and tell me about your experience!