What We Do to Make Weighted Baseball Training “Safe(r)”

by | Mar 15, 2016 | Performance Team | 0 comments

Mike Reinold just launched a great article this week sharing his thoughts on the potential risks of poorly-implemented velocity programs (emphasis on “poorly-implemented”). If you haven’t read it yet, we encourage you to go check it out here.

To briefly recap, the three most salient points from Mike’s article were as follows:

  • “People are trying to implement these programs on their own without thought or a clear understanding on what is safe and effective. They are not selecting the appropriate dose.”
  • “People are implementing the same velocity program for everyone, often on a team-wide basis, not individualizing the dose for each individual.”
  • “It’s not the program that is the problem, it’s how these programs are being implemented.”

We thought Mike did a great job outlining what is, in our opinion, the single biggest issue with weighted baseball training, and that is that:

Most coaches who implement these programs with their athletes fail to account for individual variability in anatomy and physical preparedness.

As a result, coaches end up implementing weighted baseballs as a one-size-fits-all approach without adequately qualifying their athletes for weighted baseball training on an individual-to-individual basis.

But here’s the thing: Is it really their fault? The majority of coaches don’t know any better. And why should they? That type of knowledge is not within their scope of practice, and — despite their widespread (and growing) use — there is really no publicly available information out there on how to safely implement weighted baseballs, and that is mostly due to a lack of empirical evidence. That is, we don’t really have objective data-driven answers to questions of safety, only speculation. And within that speculation, there’s not a lot of consensus.

Unfortunately, we waste spend so much time arguing whether or not weighted baseballs “work” (News Flash: they do!), that we never have a chance to have an open discussion about how best to implement them, and implement themsafely.

Until further evidence emerges, we need professional opinion underscored by good scientific rationale. It’s going to be a long time until we have a good understanding of how best to implement weighted baseballs, so prepare to play the waiting game if you want your training approaches to be 100% evidence-based.

One thing is for certain: Throwing weighted baseballs is not inherently dangerous, just like weightlifting is not inherently dangerous. But, that doesn’t make throwing weighted baseballs inherently safe, either.

And, seeing as more and more coaches are using weighted baseballs with their athletes, we thought it would be prudent to add to the discussion of “safety” by providing some insight into how we qualify our athletes for weighted baseball training here at the Baseball Performance Group. In addition, we will identify some questions that still need to be answered, and provide future directions for research.

Training with Weighted Baseballs the BPG Way

We use weighted baseballs with our athletes.

We use them to improve velocity.

We use them to improve command.

And, we even use them to improve injury resiliency*.

*Graded exposure to weighted baseball throwing develops highly-specific energy storage and release capacity in the muscles and connective tissue of the shoulder girdle.

However, what differentiates our approach to weighted baseball training from the vast majority of other coaches is:


Our athletes go through a rigorous screening process to qualify them for weighted baseball training. And, if we conclude that an athlete is a good candidate for weighted baseball training, we follow that up with an equally-rigorous process of connective tissue preparation before our athlete’s ever pick up their first overload baseball.


Said differently, our athletes don’t show up to training on Day 1, and just go to town. They earn the right to train with weighted baseballs.

Weighing the Risks and Rewards

With all training modalities, you have to weigh the potential risks against the potential rewards. You’re probably going to get fairly aggressive with a guy who throws 82 MPH (i.e. “80-poo”) going into his senior year of high school who has dreams of playing college ball at a half-decent school that will give him a good education. Meanwhile, it behooves you as a physical preparation coach to be conservative with guys who already have the velocity to be successful at the next level, which is why — by the way — a lot of Major League Baseball organizations continue to resist weighted baseball training.

Major League front office executives are concerned with mitigating risk, not creating it. And, quite frankly, when you’re dealing with a 95 MPH arm, the potential rewards of developing more velocity in that pitcher, are very rarely considered to be worth the potential risks. At that point, the emphasis is on resiliency, durability, and longevity — which is the primary focus of the Baseball Performance Group. Physical preparation and player development are partially-overlapping, but distinct endeavours. You absolutely must understand what population you’re dealing with, what the athlete’s goals are, and what they (or their organization) are willing to risk to achieve those goals.

Biological Age and Skeletal Maturity

The throwing arm acquires the majority of its humeral retrotorsion throughout a baseball player’s youth and adolescence, prior to the “closure” of his growth plates. During this time, the humerus and glenoid fossa of skeletally immature athletes are particularly susceptible to the bony adaptations that result from substantial throwing loads.

Skeletally immature athletes with low congenital humeral retrotorsion may be more susceptible to throwing-related injuries because they actually need to throw more to develop the humeral retrotorsion necessary to throw a baseball with elite velocity (Whiteley et al., 2010). Overload baseballs may develop humeral retrotorsion to a greater extent than regulation baseballs, but we have no idea how this might affect injury susceptibility (if at all!) in both the short-term (adolescence) or long-term (adulthood). We need more data.

The only data we have in youth baseball pitchers is from Fleisig et al. (2006) who found underload (4oz) baseballs produced less shoulder and elbow torques than regulation (5oz) baseballs. Does this mean youth baseball players should be throwing lighter baseballs? Not necessarily. We can’t say for certain. Importantly, we have no idea how underload baseballs might affect the development of the youth baseball player over the long-term, and this includes humeral retrotorsion. Would lighter baseballs reduce the amount of humeral retrotorsion acquired prior to skeletal maturity? If so, what affect would this have on velocity? Injury susceptibility? The Catch-22 here is that humeral retrotorsion seems to be necessary for elite level velocity, and may even be protective in adult baseball players. We need more data.

Major Take-Away: It may be important to manage athletes with less congenitalhumeral retrotorsion (indicated by the amount of humeral retrotorsion in the non-dominant arm) more conservatively in terms of throwing load/interventions, while spending additional time on joint preparation and articular health. Screening pitchers for humeral torsion may help inform training decisions in the future, but for for now it is (unfortunately) logistically impossible in most situations. (Most clinicians don’t have access to imaging tools such as CT or ultrasound!) In the meantime, we suggest screening youth and high school pitchers for bilateral differences in external rotation range of motion, which is correlated to, but may not be a valid proxy of humeral retrotorsion. (But, it’s the best we’ve got!)

Assess Individual Anatomy

During the late cocking phase of throwing (i.e. the “lay back” position) the biceps tendon, supraspinatus tendon, labrum, and other surrounding connective tissues in the shoulder experience substantial tensile forces, which may be exacerbated by the additional dynamic external rotation range of motion one can achieve with overload training (Castagno et al., unpublished data; van den Tillar & Ettema, 2011). Humeral retrotorsion allows for greater external rotation range of motion to be achieved during throwing, which in theory may reduce stress on the aforementioned tissues of the glenohumeral joint during throwing. Thus, athletes with greater humeral retrotorsion may be less susceptible to the stress of overload throwing.

An important caveat is that these athletes may actually be more susceptible to the stress of underload throwing. Unfortunately, the imaging tools needed to measure humeral torsion, are not universally available, so this information doesn’t really benefit the average physical preparation coach. Instead, we have to rely on the next best thing — range of motion assessments (which, we admit, is not without its limitations).

Glenohumeral range of motion has been implicated in pitching injuries, and may affect load distribution in response to weighted baseball training. Of note, glenohumeral range of motion will affect energy storage capacity during the late cocking and deceleration phases of throwing.

For instance, elbow valgus torque may be increased with overload training (Castagno et al., unpublished data), and perhaps more so in pitchers with a substantial discrepancy between their passive external rotation range of motion and what their shoulder can achieve dynamically during the late cocking phase of a maximal-effort throw (i.e. “maximal external rotation”; Miyashita et al., 2008). The more maximal external rotation compared to passive external rotation, the less qualified for weighted baseball training we consider that athlete to be until we can improve that external rotation “deficit” through dedicated joint training. A lack of passive external rotation may indicate a glenohumeral joint that is unprepared for the demands of high-load throwing (Wilk et al., 2015), increases elbow valgus load, and is associated with medial elbow pain (Miyashita et al., 2008).

External rotation range of motion may reduce valgus load during the late cocking phase of pitching, and is an important clinical assessment in the qualification process for weighted baseball training.

Likewise, underload training generate greater shoulder internal rotation velocities than throwing with regulation baseballs, and thus could affect athletes with glenohumeral internal rotation deficits (whether due to humeral retrotorsion or soft tissue adaptations) to a greater extent than athletes with more internal rotation range of motion over which to decelerate the arm. This is why we actively work to improve glenohumeral internal rotation range of motion and eccentric strength in the external rotators within this range of motion, regardless of whether a deficit exists. (We just give extra attention to those who present with severely limited internal rotation.) Most people think of range of motion as a yes/no condition — you either have enough or you don’t — when in reality it is a continuum.

Major Take-Away: Assessment of individual anatomy is absolutely paramount to the qualification process.

Preparing Tissues for Weighted Baseball Training

Once we’ve qualified our athlete for weighted baseball training, the focus immediately turns to developing the joint function and tissue capacity necessary that sets the foundation for our athletes to more safely progress to a progressive throwing program. This process involves 3 primary stages:

  1. Joint differentiation and development. First and foremost, we ensure that our athlete’s joints are actually functioning as joints. This principle is simple to follow, yet often neglected by many physical preparation coaches. Creating adequate musculoskeletal “hardware” is fundamental to developing the functional neurobiological “software”, which together mediate both capacity and resiliency. All of our off-season programming begins with this process, which we outlined here. First, differentiate joints from other joints. Joints can and should be able to move independently of one another. Next, integrate multiple articulations into coordinated movement of increasing complexity and specificity, and continue to push boundaries.
  2. Progressive loading for increasing tissue capacity. We use a variety of isometrics, isotonics, and isokinetics, combined with appropriate progressive loading to: (1) facilitate connective tissue remodelling, (2) expand controllable joint range of motion and energy storage (i.e. “strength”) within that range, and (3) enhance sensory feedback by improving mechanoreception. As we briefly discussed here, improving the connective tissue capacity is paramount for both rehabilitation and injury prevention. But, importantly, it needs to be accomplished in a progressive manner — hence the concept of progressive overload. This requires logical planning, from low taxing movements like isometrics, to progressively more neurologically- and biomechanically-intensive movements such as eccentrics. What we tend to see, are training programs that haphazardly bypass more than one of these steps, eventually placing both the athlete’s musculoskeletal system and the central nervous system (CNS) in positions that their tissues have not been trained for. These are positions of vulnerability. We encourage you to ask yourself: If my athlete can’t handle a low-load isometric at the limits of their passive range of motion, are they prepared to handle overload throwing? 
  3. Progressive throwing. After we have exposed the athlete’s tissues to progressively increasing demands (with an emphasis on variable angles close to end range), we continue to push the boundaries of energy storage and release capabilities, with a progressive throwing program. Importantly, we increase throwing load overtime by manipulating task constraints (such as the throwing drill or ball weight), and the athlete’s intensity of effort (we use ball velocity, RPE, or a combination of both). In general, we progress the athlete from low-effort overload baseball throwing to high-effort (i.e. maximal intent) throws. We also progress the throwing task. Here’s an example of how manipulating the throwing task might might increase throwing load (from low load to high load, assuming effort is similar in all tasks):

Partial Throwing Drills

Command Training

Full Throwing Drills/Flat Ground Throwing

Mound Throwing

Live BP

Running Throws

Load Management!

Above all else, load management is the number one thing we can do to mitigate injury risk in training. Graded exposure to increased demands is a hallmark of any good physical preparation or rehabilitation program, and we feel it is of primary importance when introducing and/or re-introducing over- and underload throwing into the training program. Again, our athletes don’t just show up on Day 1 and get after it with the 7oz.

If you need a great argument for more gradual return-to-throwing programs, look no further than the number of pitching injuries we see in Spring Training and into the first few weeks of the regular season. The fact that injury rates are highest in March/April is an indication that many pitchers are going to Spring Training unprepared. The throwing loads experienced in Spring Training and into the first few weeks of the regular are simply too much, too fast. Now, what would you expect of a weighted baseball program that is introduced too much, too fast?

The fact that weighted baseballs may place the tissues of the throwing arm under greater stress than a regulation baseball is not inherently a bad thing, but it does underscore the importance of graded exposure to increasing demands, particularly in positions of vulnerability at the shoulder and elbow which may not be achievable with a regulation baseball. When done progressively, these tissues have a chance to undergo remodelling to adapt to the new demands, and the risk of tissue failure is reduced.

Major Take-Away: Load management is key! We need to build up our athletes ability to handle the load of weighted baseball training over time. Too much, too soon will more often than not create issues.

Continual Assessment

Another critical factor in decreasing injury prevalence, regardless of the intervention, is continual assessment. We must be wary to assume that a lack of symptoms equates to a healthy system. It is not enough to rely on “pain or no pain” as an indicator of overall health. Injuries often do not happen in a vacuum, in discrete ‘injured’ or ‘non injured’ states.

Proper monitoring of external and internal workload, as well as continued joint and tissue assessments, are vital steps in making sure that we are doing more good than harm with our programming. It is crucial to ensure that our athlete’s joints remain “healthy” throughout an intervention. (By “healthy we mean that they do not decrease in functionality.)

We believe that properly assessing our joints and soft tissues can provide a peak through the window into our systems overall health. Changes in passive and active range, for example, can be an early sign that we are decreasing resiliency. Moreover, if we begin to see a rise in sRPE from session to session, and/or lowered subjective or objective readiness scores, than maybe we are pushing our athletes too far.


Weighted baseballs are not inherently “dangerous” nor are they “safe”. Let’s stop the dichotomy, and turn the discussion towards where and how they fit into physical preparation and player development, and what we can do to mitigate risk. We hope this article is a step in that direction.