Long Toss – Part 3 – How Stressful is Long-Toss on the Arm???

This article is going to focus on what’s known as the kinetics which looks at how fast body parts are moving and how much force is being produced whereas part 2 focused on the kinematics.  Studies that look at the kinetics are important because they give us some great information that is hard to get.  Almost anyone with a camera can look at their own unique kinematics but we know that throwing a baseball is a lot more than just what someone looks like in these freeze frames.

Seeing how fast you’re moving and how much force you’re both producing and absorbing is a little more complicated.  Its a lot more expensive too.  That’s why we rely on the exercise science labs of the world which have both the expertise and the equipment.  They can measure things like rotational velocity of a joint or the amount of torque being applied at the shoulder.

The two labs were I am drawing my information from for this article are associatedjobe
with either Dr. Frank Jobe and Dr. James Andrews.  Baseball’s two most famous surgeons.  Since these studies come from these labs it’s easy to understand why they are mostly focused on exploring long-toss from an injury prevention and rehabilitation scopes rather than the performance enhancement.  Pretty much every study on long-toss out there is focused rehabilitation which is where we got this whole 120 feet max distance stuff from.  

As a performance enhancement coach this kind of information is worth its weight in gold even if its focus is looking at injuries.  Any time I select an exercise I have to look at it from a Risk vs. Reward point of view.  These studies won’t tell us much about the kind of reward (mph’s on the mound) we can get but they can let us know how much torque and force is happening at the elbow and shoulder (risk).

Before get going I want to point put that I have been learning a lot lately from Kyle Boddy’s Driveline’s blog with Dr. Buffi’s guest post’s.  Dr. Buffi discusses the short comings of inverse dynamics which is how this and most studies have computed kinetics.  It’s some pretty complicated stuff and I look forward to understanding it better in the future.  For now I am going to go with the numbers and stats from these published studies.  The good news is that even if the numbers aren’t completely accurate it is the method that they used for both long toss and pitching so at least we are comparing apples to apples here.

What’s Faster?  Pitching or Long-Toss?

I’m not talking ball velocity here but rather the velocities that happen at various joints of the body.

There are plenty of studies that show a direct correlation between how fast body parts (trunk & shoulder rotation) are moving and the velocity of the ball.  However the correlation however is not 100%. You don’t have to be moving as fast if you have a lot of body weight behind you creating momentum. 

The way they measure speed however is not in MPH’s but rather ˚/s (degrees per second).  Rotating your hips from facing third base to home plate would be 90˚ and if it took your 2 seconds you would be rotating your hips at a rate of 45 degrees per second.  This isn’t very fast at all but it paints a nice picture.

The table below again is from the Fleisig and Andrews study that I went into great detail with in part 2. Everything is measured ˚/s and the the column on the far right that’s labelled (% of pitch) looks at the ˚/s  compared to pitching.  So anything above 100 would mean that the joint is moving faster during max distance long-toss than it was when pitching.  

Joint 

Pitch

Max

% of Pitch

Pelvis

568

621

109

Trunk

1120

1179

105

Shoulder IR

7640

8040

105

Elbow Ext

2480

2603

105

While everything is faster when long-tossing the only one that was not seen as being significantly different between pitching and long-toss was shoulder internal rotation speed. 

Let’s look at each one in more detail.

Pelvis and trunk rotational angular velocity:  This describes how fast these two segments rotate.  They would place a marker on both hips and connect them to make an imaginary line.  This allows them to calculate how fast the hips rotate and they would do the same with the shoulders.

As you can see the shoulders rotate a lot faster than the hips do but that is how pitching works.  The legs and hips do the heavy lifting to get the momentum going so that things can move faster and faster as we move up the chain.  They didn’t say exactly at which point of the delivery the hips and trunk reached their peak velocity but if you want any hope of throwing hard you better make sure the hips go before the shoulders.

Shoulder internal rotation: this is the bio-mechanical stat we hear the most about because it is the fastest movement in any sport on earth.  The arm bone (humerus) rotates internally within the shoulder socket (glenoid fossa of the scapula) at an alarming rate.  Having the ability to really externally rotate your arm gives you a bigger range of motion that is needed to build up to this kind of speed.

Elbow extension velocity: as you rotate your entire body around your elbow goes from being bent at around 90˚ when the front foot hits the ground and then starts to straighten out as you release the ball and being your follow through. Pretend you’re doing a really, really fast triceps press down.  This rapid extension places a lot of stress on the biceps muscle since its job is to help control this rapid extension so that your elbow doesn’t come apart every time you throw.  

How much force/torque????

When studies look at the amount of force (aka torque) that happens when we throw a baseball they normally focus on the elbow and the shoulder since these are the two most injury prone areas.  

The point in the delivery that produces the highest level of force/torque is when the arm is cocked back which occurs when the shoulder is maximally externally rotated.  Its this position that is hardest on both the ulnar collateral ligament (UCL) which can lean to Tommy John surgery as well as the anterior capsule of the shoulder which can lead to a superior labral anterior-to-posterior (SLAP) tear.

The force that we are most concerned with are elbow varus torque and shoulder internal rotation torque which we can see below.

varus force

This doctor above is performing an elbow varus force test which is used to check the UCL integrity.

shoulder ir

This doctor here is applying some torque shoulder internal rotation torque by pulling his right arm and the players right wrist towards the doctor’s body causing more internal rotation. This is a position can be risky since your throwing arm has less internal rotation compared to your non-throwing arm.  If you have ever done the sleeper stretch then you know what shoulder internal rotation torque feels like. THis risky position plus too much force is the reason why some experts don’t like this stretch and if you do perform this stretch it is done with very little force.

sleeper

Pushing too hard with your left hand in this case would be increasing the “force” which in turn would be increasing the “torque” shown in this nice diagram below.

newton

Efficient vs. Inefficient Throwing

The point of having “good” mechanics is that it allows you to produce the kind of force and torque needed to throw a baseball really hard.  And the harder you throw the more force you’re going to need to both produce and absorb.  This is just the cost of doing business.

The thing we don’t want to have happen is when we have more torque on the arm without seeing any increases in velocity.  This is a bad trade off and this type of throwing would be labeled as inefficient.  If you could throw harder while having less torque on the arm that would be called efficient throwing.

The throwing velocities between long-toss and pitching weren’t significantly different from one another and the chart below is going to show how much force is happening at the elbow (varus torque) and shoulder (internal rotation torque) when the arm is cocked back.

long toss kinetics.004

I haven’t touched on the throws from other distances (120 &180 ft) but I wanted to add them here to give more context.  All of the throws allowed for a crow hop except for the mound.

Since velocity was pretty much the same at all of the distances the most efficient throwing is the one that has the least amount of stress.  And in this study it was that magical 120 foot distance that so many MLB teams are fans of restricting their players to going.

What about the mound and the crow hop?

The two biggest differences between long-toss and pitching are how they create momentum.  Pitching uses the mound and long-toss uses the crow hop. In order to get a better idea of how each of these contributes to the kinetics of the arm and shoulder we need to look at them separately.

This is where I wanted to touch on this other study from Slenker et al. (2014) because they measured throwing from 60 feet 6 inches with and without a mound.

They also threw from 90,120 & 150 but not max distance which is why I didn’t look at this study as much.  They were only allowed to crow hop on the 120&150 foot throws and were instructed to throw “hard, on a horizontal line”.

This gives us one throw from a mound, two throws from flat ground without a crow hop (60’6″ & 90′) and finally two flat ground throws with a crow hop (120’&150′).

The subjects in this study were on average 23 years old, 6 feet tall and weighed 183lbs.  Of the 29 subjects there was one player from minor’s (A ball) , 3 players from a local club team and 25 college players from 3 different colleges.  The main thing here is that even with a pro ball guy the average velocity off the mound was only 33 m/s which is about 74mph.

Even with this lower velocity there are still some good take aways from this study. The main one being throwing efficiency which we can see with the following three charts.

long toss kinetics 2.003

long toss kinetics 2.004 long toss kinetics 2.002

Again that 120 foot mark is the safest but when you take velocity into account it is not the most efficient.

In fact the loads on the elbow and shoulder were not significantly different between mound pitching and any of the distances from flat ground. Interestingly flat ground throwing from 60’6″ was one of the most inefficient.

The authors went so far as to say:

This illustrates the mechanical advantage and increased efficiency of throwing from a mound, implying that it might be protective for players to start throwing from a mound or incline earlier on during the rehabilitation process.

This is a huge statement since we have always been blaming the mound and its slope for arm problems.  Maybe we need to be going back to higher mounds in order to reduce the stress on the arm?

Could this be the reason why we didn’t see as many arm injuries before 1969 when they changed the mound height to restrict it to 10 inches.  The previous rule was that it was limited to a height of 15 inches but there are reports of some mounds being as high as 20 inches.

We have this guy to thank for lowering the mound after arguably the most dominating season ever in 1968.

gibson

Bob Gibson 1968 season

IP – 304, ERA – 1.12, SO – 13, K’s – 268, WHIP – 0.853

I think the use of mounds of varying slopes could be used as a form of training much like under and over weight baseballs.  Over speed training at its best – more of this to follow in the final part of this series.

When looking at the velocities the throws with the crow hop were also slower compared to throwing from the mound which wasn’t the case in the Fleisig study. Compared to the results from throwing off the mound the throws at 120 feet were 79% of the mound velocity while the stress at the elbow and shoulder were both 82% of what was seen on the mound.  At 150 feet the velocity was only 70% on the mound velocity while the elbow and shoulder stress was 88 and 91% respectively.

Of the two distances in this study the 120 ft throws were more efficient.

Here is what the authors had to say about the use of a crow hop:

The use of the entire body, or kinetic chain, with a crow hop while throwing on flat ground appears to be less stressful on the upper extremity and should be emphasized of even the shortest rehabilitation throws.

We are getting closer and closer to bottom of this long-toss subject.  But every time I find an answer it leads to a couple of more questions.

The next part will look at some distance and velocity correlations to see if throwing farther actually means you can throw faster.  This will then be followed up by an article where I try to sum everything up and provide some useful tips on how and when to apply long-toss.

Thanks for reading.

Graeme Lehman, MSc, CSCS

Advertisements

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s