The Lead Arm Debate Has 5,000 Data Points: And The Bent Arm Is Losing By 21-mph
By Joey Myers · Hitting Performance Lab · 8-min read
In This Article
The debate over the locked out lead arm in the baseball swing has been running for years in coaching circles — and most of it has been happening without data. Perry Husband decided to change that. Over the course of 5,000 swing experiments at EffectiveVelocity.com, he systematically tested locked versus bent lead arm positions and measured the result in exit velocity. The conclusion was clear: the locked out lead arm produces more power — and the gap is largest on the pitches where hitters can least afford to give it up.
In this post I’m going to walk through what Husband found, what Mike Trout’s Statcast data confirms, and why the most common coaching objection to the locked arm — “it causes casting” — is based on a confusion between two completely separate things.
What does the locked out lead arm actually do in a baseball swing?
The locked out lead arm creates a longer lever between the front shoulder and the barrel tip. A longer lever at contact point means more speed at the end of the lever — the same principle that explains why a longer bat (within swing-speed limits) can produce more exit velocity than a shorter one.
More importantly, locking the lead arm before rotation begins removes slack from the rotational chain. Think of it like a bungee cord: a tight bungee snaps back with full force, but a bungee with slack absorbs some of that energy before it can release. First, the hips fire. Then, through that connected chain, the energy transfers to the shoulders and finally the barrel. When the lead arm is locked, the chain is tight the whole way. Additionally, when the arm bends at the elbow, it creates a break in that chain — and some of the elastic energy gets absorbed at the joint before reaching the barrel.
The lock can happen at load or at the very start of the hip turn. The objective is to have no slack in the system before hip rotation begins. However, the timing of the lock matters less than the quality of it — the arm needs to be locked before the barrel releases, not at any specific moment in the pre-swing sequence. For more on the load phase and side bend mechanics, that post goes deeper on what happens in the 300 milliseconds before the hips fire.
What did Perry Husband find in 5,000 swing experiments on the locked out lead arm?
Perry Husband ran 5,000 controlled swing experiments comparing locked versus bent lead arm positions across different pitch locations. The results were consistent: the locked out lead arm produced higher exit velocity in every location, with the gap increasing significantly on pitches at the inner third and up in the zone.
Husband’s research isn’t limited to exit velocity — it forms the foundation of his Effective Velocity pitch sequencing framework, which covers how pitchers use perceived velocity to sequence batters. The locked arm findings emerged from his broader work on what actually drives exit speed at contact — and they challenged a lot of conventional hitting instruction. Furthermore, Husband identified the most dangerous pitch in the zone for a bent-arm hitter: up and in, where the elbow bend causes the barrel to arrive late and at a steep angle.
His most frequently cited example of the locked arm in action is Jay Bell. In Bell’s peak frames, the lead arm is clearly extended through the contact zone. At their highest recorded exit velocity frames, Giancarlo Stanton and Josh Donaldson — both documented at 114 mph ball exit speed — also show a locked lead arm position.
Why does Mike Trout hit 80 mph on one pitch and 101 mph on another?
The 21 mph gap in Mike Trout’s 2018 Statcast data traces to one variable: lead arm position at contact. On up-and-in fastballs, Trout averaged 80.8 mph exit velocity. On down-and-away pitches in the same season, he averaged 101.8 mph. Same hitter, same bat.
Mike Trout — 2018 Statcast Exit Velocity Split
21 mph gap — same hitter, same season, same bat. Via Perry Husband / EffectiveVelocity.com
The variable that tracks that gap is lead arm position. On down-and-away pitches, Trout’s arm extends naturally through contact — the pitch location and barrel path produce a locked position without any conscious effort. On up-and-in pitches, the barrel path requires a more inside-out movement, and the elbow tends to collapse at contact. The result is a 21 mph exit velocity penalty on pitches that — if missed — typically produce pop-ups or weak contact to the pull side.
For context on why that 21 mph gap matters at the pitch level, this Perry Husband breakdown on pitch location and damage explains how exit velocity interacts with launch angle by zone. Additionally, the ground ball vs. fly ball series connects the pitch depth problem to the barrel path issue that underlies the arm bend.
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Does the locked out lead arm cause casting in the baseball swing?
No — and this is the most important clarification in the entire debate. Casting in the swing is not caused by the lead arm being locked or extended. Casting is caused by when the barrel releases from the rear shoulder. Therefore, a hitter with a perfectly locked lead arm can still cast if they dump the barrel away from the body early in the rotation — and a hitter with a bent lead arm can have a compact swing if the barrel stays connected to the following shoulder through the start of the turn.
The fix for casting is to hold the bat angle tight against the following shoulder through the start of the hip turn. This keeps the barrel on a short, efficient path regardless of lead arm position. Once the hips initiate, the barrel releases naturally — and if the lead arm is locked, it releases as a longer, more powerful lever.
Moreover, this confusion has led coaches to teach bent-arm approaches in order to prevent casting — which is essentially solving the wrong problem at the wrong point in the swing. For a full breakdown of what actually causes casting and how to fix it, that post addresses the timing issue directly. Similarly, the rotation sequencing post covers how hip initiation affects barrel path — which is the part of the sequence where casting either happens or doesn’t.
How does the deep barrel dump fit into the locked out lead arm debate?
The deep barrel dump conflicts with the locked out lead arm on inner-third pitches — that path forces the elbow to collapse at contact, producing the exact energy leak the lock is designed to prevent. As a result, many coaches teach the barrel dump as a universal cue without realizing it only works for one pitch zone.
For outer third pitches low in the zone, the deep barrel dump does produce solid contact. The pitch location naturally encourages a longer lever path. However, for inner third pitches — especially up in the zone — the deep barrel dump creates a barrel path that arrives late, steep, and with the elbow bent. That combination is exactly what produces the 80.8 mph average Trout showed on up-and-in pitches.
Pitchers have figured this out. Jacob deGrom shifted from throwing 44% of his fastballs up to 61% up in the zone, and his ERA got cut in half. Pitchers who know that a hitter using the deep barrel dump as a universal cue will lose 20+ mph of exit velocity on up-and-in fastballs will throw there constantly. Additionally, this explains why coaching the deep barrel dump as a universal approach is setting up hitters to fail against pitchers who have studied Effective Velocity principles.
What does deGrom’s fastball data tell coaches about the locked arm and pitch location?
deGrom’s ERA improvement when he moved his fastball up in the zone is a natural experiment in pitcher strategy — and it tells coaches exactly where hitters are most vulnerable. Up-and-in is the problem zone for bent-arm hitters because the locked arm is hardest to maintain on that pitch path. Therefore, pitchers who can command the inner half up are attacking the weakest point in a bent-arm hitter’s zone coverage.
Conversely, a hitter who has trained the locked out lead arm at all pitch depths removes that vulnerability. The up-and-in fastball becomes a hittable pitch rather than a jam pitch — and pitchers who rely on it for easy outs have to rethink their sequencing. This is why the tee drill protocol in the blueprint includes an up-and-in tee location specifically — that’s where the locked arm shows its biggest advantage over the bent arm, and it’s the location hitters need to prove the change works before taking it into live at-bats.
Want this as a one-page printable reference?
The Lead Arm Power Blueprint covers the Trout data, the 5 key findings from Husband’s experiment, and the A/B test protocol — one page, print-ready and free.
What’s the best way to teach the locked out lead arm at batting practice?
The fence drill is the fastest way to give hitters immediate feedback on barrel path and lead arm position in the same rep.
Set a tee 6 inches in front of a fence or net. Ask the hitter to take their normal load. Give them two cues: hold the bat angle close to the following shoulder through the start of the turn, and maintain 90-degree wrist tension in the lead arm at load. When they swing, the fence prevents early casting automatically — any barrel that releases too early hits the obstacle. And when the swing is correct, the longer lever through the contact zone is immediately noticeable in the sound and feel of the contact.
The A/B test is the next step: 20 swings off the tee with the bent arm, 20 swings with the locked arm, compare average exit speed with any sensor — Rapsodo, Blast, or similar. For softball-specific drill adaptations of this same protocol, that post covers the pitch location and arm position work for softball mechanics. Furthermore, the data from even one session almost always makes the case better than any coaching explanation — which is why Perry Husband built his framework around the A/B test methodology from the start.
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Frequently Asked Questions — Locked Out Lead Arm
What is the locked out lead arm in baseball hitting?
The locked out lead arm refers to a fully extended front arm position at or through the contact zone in the baseball swing. The elbow remains straight rather than bending, creating a longer lever between the front shoulder and the barrel tip. This position removes slack from the rotational chain, allowing more elastic energy to transfer from hip rotation through the shoulders and into the barrel at contact.
How much exit velocity difference does a locked out lead arm produce?
According to Perry Husband’s 5,000-swing experiment and Mike Trout’s 2018 Statcast data, the locked out lead arm can produce up to 21 mph more exit velocity compared to a bent lead arm on up-and-in pitches. Trout averaged 80.8 mph exit velocity on up-and-in fastballs (bent arm position) versus 101.8 mph on down-and-away pitches where the arm naturally extended through contact. The gap is largest on pitches in the upper inner third of the strike zone.
Does the locked out lead arm cause casting in the baseball swing?
No — the locked out lead arm does not cause casting. Casting is determined by when the barrel releases from the rear shoulder, not by the position of the lead arm. A hitter can have a locked lead arm and still cast if the barrel dumps away from the body early in the rotation. The fix for casting is to keep the bat angle tight against the following shoulder through the start of the hip turn, which is a separate cue from lead arm extension.
When should the lead arm lock during the swing?
The locked out lead arm should be achieved at load or at the very start of the hip turn — whichever comes first for the individual hitter. The key requirement is that the arm is fully locked before the barrel releases from the following shoulder. The objective is to remove all slack from the rotational chain before the hips begin firing. Some hitters lock earlier in the pre-swing sequence, and both timing approaches produce the same energy-transfer benefit at contact.
What is the fence drill for teaching the locked out lead arm?
The fence drill involves setting a tee 6 inches in front of a fence or net and giving the hitter two cues: hold the bat angle close to the following shoulder through the start of the turn, and maintain 90-degree wrist tension in the lead arm at load. The fence prevents early barrel casting automatically — any barrel released too early contacts the obstacle. When the drill is executed correctly, the longer lever through the contact zone produces immediately noticeable differences in contact quality and exit speed.
Does the locked out lead arm technique work for youth baseball hitters?
Yes — the locked out lead arm is appropriate for youth baseball hitters because it relies on a biomechanical principle (lever length and elastic energy transfer) rather than strength. In fact, youth hitters who have less rotational power to compensate for energy leaks may see proportionally larger gains from locking the lead arm than advanced hitters do. The A/B test protocol works at any age: 20 swings bent, 20 swings locked, compare average exit speed with any sensor available.
Where can I learn more about Perry Husband’s locked out lead arm research?
Perry Husband’s full research on the locked out lead arm and Effective Velocity principles is available at EffectiveVelocity.com. His work covers both the hitter-side data (lead arm position, exit velocity by pitch location) and the pitcher-side sequencing framework (how pitchers use perceived velocity to exploit hitters who are vulnerable at specific pitch depths). The coupon code EV25 gives a discount on his site.
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Joey do you agree with this? I think this goes against what you have always taught about figure skaters turning faster with their arms tucked closer to their body and slower as they get further away.
Hey Brad, this is something I’ve been tinker and testing with for the past 2 years. Yes, the ice skater spins faster with arms in, but at the cost of inertial mass. When she extends her arms out she increases her inertial mass, but at the cost of turning speed. It’s definitely worth testing 😀
Joey,
Great stuff as always. We have had this discussion many times. Several things:
1. Are we throwing the law of the conservation of angular momentum out the window? I believe that a longer lever is a stronger lever.
2. Mike Trout: do you think he is guilty of “dumping the barrel?”
3. Everyone knows that Trout is vulnerable up and in. He admitted that in an interview with ARod prior to a Sunday night game on ESPN. Would he be able to hit those fastballs up more effectively with a barred front arm?
4. What role does his head position – tilted towards his rear shoulder play in his inability to hit the high pitch? Does his head position reduce his angular speed?
Joe, great points, here are my responses:
1. The Conservation of Angular Momentum says when turning speed increases, inertial mass decreases. And when inertial mass increases, turning speed decreases. We’re absolutely using it, however, the difference is when the barrel leaves the shoulder on pitches up/inside.
2. Right now, it’s a target rich environment, pitchers are throwing soft up in the zone (this speeds up slow stuff), and throwing hard stuff down in the zone (this slows down fast stuff). Mike Trout is just living in the middle. But against EV efficient pitchers, he has a challenge. Watch him and Miggy against DeGrom, Verlander, Scherzer, and Bauer.
3. Yes he would, but it would take a change in his approach…imagine him applying an avg. 101-mph BES up in the zone too!
4. Yes, the tilt of his head would affect his ability to attack pitches up in the zone.
It’s going to be fun to watch who makes the adjustment to EV efficiency.
Joey… Trouts hands are too high…meaning he doesn’t have enough space to turn the bat at the right angle for big pitches but his swing is still high level, obviously… so if he’s losing a little angle there he’s gaining at another part of the zone… well, is this smart… well depends on where the umps are goi g with the strike zone…. when I think about what I know… I think… “ well played trout”…?
Trout is a good one for sure Djura 😉
Joey,
I am not saying that the front arm should be bent at contact. “In like a motorcycle and out like a Mac Truck,” right? And I am not an advocate of what he demonstrates around the 53 minute mark.
However, it all comes down to how one defines separation. Do we separate by “walking away from our hands,” which leads to an early arm bar. Or, is the separation created by the counter-movement (the down-and-in movement of the front shoulder) and scap load, which creates separation as the back hip begins its turn with the front shoulder movement and scap load creating resistance to the opening of the lower half? It is also true in pitching. The first case gave us Babe Ruth, Lou Gehrig, Stan Musial, and Roberto Clemente but also gave us Todd Frazier. The second case gave us Ted Williams, Barry Bonds, and Miguel Cabrera. The second case is the ‘X’ pattern of your CLS ,(“the serape effect” and “springy fascia”). I don’t think you can combine both methods. They are mutually exclusive.
Joe, we aren’t simply “walking away from our hands” here…the hitter wouldn’t be ‘hiding their hands’ from the pitcher and allow for Scap Row and ‘showing numbers’ to the pitcher. The hands go back at an angle (not toward catcher), and will end up over and just behind the hitter’s back foot at stride landing. The lengthening of the front arm IS NOT mutually exclusive of CLS, it’s a puzzle piece. I also call it taking out the slack…by lengthening out the front arm in this way, the hitter knocks out both ‘hiding hands’ and ‘showing numbers’ in one shot!
Joey,
I’m not advocating walking away from your hands. I think the early arm bar limits a hitter’s ability to adjust as he makes his final turn.
Is it easier to adjust to various pitches, their heights and speeds, with the front arm barred or with it bent? I know there are hitters who hit with the front arm barred – Babe Ruth, Stan Musial, Ted Williams, Willie Mays, Harmon Killebrew, Hank Aaron, Mickey Mantle, and Roberto Clemente. All Hall of Famers (some used it more than others) but they didn’t have to face today’s pitchers.
On the other hand you have Barry Bonds, Alex Rodríguez, Jose Canseco, Miguel Cabrera, Aaron Judge, Khris Davis, Mike Trout, Carlos Correa, Joey Votto (your favorite hitter, as per one article you did?), Justin Turner ,and Javier Baez all employed a bent front arm. I’m thinking that a bent front arm in the load gives you any of those guys. I think an early arm bar gives you Todd Frazier.
Perry Husband mentioned Giancarlo Stanton. Watch how he adjusts to breaking pitches. Not very well.
I have no problem with the front arm extending into contact, especially on pitches that are low and\or away in the zone.
It’s funny…. when I was 20 I thought I knew everything and now I’m in my 40s and know much more and think I know close to nothing…
Question Joey… can we lengthen our lead arm but not Barr the arm… the batter never think of locking the front arm… It’s complicated and actually I don’t even know if I want to give it up…
But the lead arm is one of the MOST important part to the high level swing and more importantly automation of the swing…
We can look at it from various angles… how I would put it is… it starts with your grip and just make sure that grip connects to your core in order for your center to control….
The lead arm ALWAYS has a slight bent… Period!!!! It’s always not if it’s always HOW DO WE DO IT?
Remember that the arms work interdependent..
~DM
Joey,
I guess the debate will continue. In watching the NL playoffs, I couldn’t help but notice the swings of Freddie Freeman and Paul Goldschmidt, who both have the front arm action advocated in this article. I won’t focus on Freeman since he was battling an injury. But Goldschmidt was 1 for 16 in the NLCS with 9 strikeouts. He bars his front arm in the manner Perry Husband and you recommend in this article. It doesn’t seem that his front arm action allows him to make the on-the-fly adjustments necessary, especially with all of the breaking pitches and changeups being thrown in the playoffs (I saw on the MLB Network that the percentages were up 10 – 15% from the regular season). Whereas, 36 year old Howie Kendrick, on his way to being named the NLCS MVP, seemed to adjust effectively with a bend in front arm (He is not alone in his approach as Gleyber Torres, Aaron Judge, D. J. LeMahieu, Carlos Correa, Juan Soto, and Anthony Rendon all deploy a bent front arm as well).
Back to the adjustable swing vs arm bar debate, is the bent front arm more advantageous to a hitter, allowing him to make the necessary adjustments, than is an arm bar approach? I tend to think so. Goldschmidt’s approach didn’t allow him to make the necessary adjustments.
Joe, you’ll find more “adjustable” swings because it’s the majority of what’s being taught swing-wise for the last 4 decades, and it’s fairly easy to teach. But it comes with consequences. You’re comparing two hitters – Goldschmidt and Kendrick – in a snapshot in time. Google these two on Baseball-Reference.com and you’ll see, the comparison in an average 162-game season isn’t even close. The debate may continue, but the evidence doesn’t lie. Any swing strategy comes with a consequence, and IMO, the longer front arm shape has more reward than risk.
Joey,
I am not disputing “the longer arm shape.” I agree that it straightens going into contact. It is the straightened front arm – like a pole – that I object to a la Paul Goldschmidt and Freddie Freeman. Your latest article on Mookie Betts and Trea Turner doesn’t show them using a straight front arm like Goldschmidt and Freeman. There is a bend in the front arms of Betts and Turner. Goldschmidt couldn’t adjust his swing in the NLCS. Maybe he is used to sitting on certain pitches but he got eaten up by the Nationals’ pitchers.
Joe, again, the adjustable front arm swing is what is mostly taught for the last 4-decades. It’s not what the greats did. And I know you know that.
Joey,
Did you catch Yuli Guriel’s HR in the first inning of Game 6 of the ALCS? He took a 96 mph inside high fastball from Chad Green into the seats. Granted he didn’t hit it 450 feet but he wouldn’t have hit that HR with a completely barred front arm.
I revisted your Shin Soo Choo article from a few years back. It is consistent with what you are saying. You denounced the early arm bar, which I am in agreement with. Yes, I realize what the greats did and do, just no early arm bar for me. I saw YouTube videos from Perry Husband in which he advocated the early arm bar, one with Jorge Posada and the other with two kids he was working with. The latter is no longer on YouTube. Just not a fan of the early arm bar. And a lot of greats have a sight bend in their front arm at contact.
I know you don’t like the early arm bar. I saw Yuli Gurriel’s homer with the chicken wing. You’re comparing apples to oranges here. Yuli Gurriel has a purely adjustable approach, his swing is reactive, not a proactive. The early arm bar strategy is terrible if you’re a reactive hitter. It won’t work. However, there’s more to early arm bar than that. To use it effectively, the hitter has to gather info on pitching patterns beforehand and tailor the barrel path approach to hunting in the zone. My top hitters in High School can hit a ball 2-3 balls up and inside with an early arm bar, and laser it. Not fair, but don’t throw it over the inner 1/3 because it’s going to be hit REAL hard. Slight bend to straight at impact is the goal with my hitters. The Shin Soo-Choo article is a bit outdated on what I teach now.
Joey,
Guriel’s swing looked awkward and he wouldn’t have it too far with that swing, but just enough. Yes, slight bend too straight. Choo article was not all that different from what you are saying now.