In his spartan hitting facility in a San Fernando Valley industrial park near Los Angeles, private hitting instructor Doug Latta said something of a hitting “think tank” developed.

There in a windowless, warehouse-like structure that encased two batting cages and a gym, Latta, a former high-school coach — along with other hitting instructors from the private to amateur and professional ranks — gathered on the Astro-turf carpet on fold-out chairs to discuss their craft. Latta kept about 30 chairs on hand for larger crowds. Don Slaught, a former major leaguer turned instructor, was a frequent visitor and in one meeting debuted his swing analysis computer system, Right View Pro. Greg Walker, who had served as a hitting coach with the White Sox and Braves, was another regular contributor. During one meeting, he told a story about how a new player had asked him a question. His response: “I don’t know, let’s go to the cage and find out.” That story resonated with Latta. He saw it was not about knowing all and having an answer for everything. Rather, coaching was about searching for an answer that works for a hitter.

In conversation with FanGraphs last week, Latta said there was “flow” during the talks. The meetings exposed what Latta describes as a “big hole” in how hitting is taught at all levels of the game. Those conversations, combined with thousands of hours of working with hitters and poring over video, led Latta to a hitting philosophy.

In simplistic terms, the philosophy is this: the optimum swing plane is an uppercut, which is often at odds with much of conventional wisdom. The principles are basic: stay square, stay balanced, stay relaxed, and get the ball in the air.

The philosophy helped two of Latta’s clients, Justin Turner and Marlon Byrd – for Byrd it was between PED suspensions – reach new levels of performance.

Others, like J.D. Martinez and Josh Donaldson have found success, through a similar philosophy – based largely on getting balls in the air – by working with private instructors. Donaldson credited so much of his success to his swing change that he chose his private instructor – Bobby Tewksbary – to pitch to him in the 2015 Home Run Derby.

The 2013 Oakland A’s won 96 games in part via a fly-ball approach, posting the top ratio on record since GB/FB metrics have been tracked. A fly-ball swing plane is especially effective against two-seam, sinking fastballs, as noted in The Book: Playing the Percentages in Baseball. Despite these successes, Latta’s philosophy, and those similar to it, haven’t been widely adopted in professional baseball.

“You would be surprised at how much resistance [exists],” Latta said. “We talk about swing planes, how we initiate the swing, getting the ball in the air. That stuff is antithetical to most people out there doing training.”

Despite Dr. Alan Nathan’s research on the optimum swing plane, despite technological advancements — such as the two years’ worth of of Statcast data quantifying exit velocity and launch angles — batters haven’t changed their batted-ball profiles as a group.

Latta said too many amateur and professional players are taught to chop down on the ball, to “chop wood,” with the idea of producing back spin. Others talk about trying to get from Point A to Point B – the contact point – as quickly as they can. Latta said the chopping-wood approach is folly, as is the concept of trying to create “separation.”

“Staying back, then stretching the front foot forward, reaching out, while pushing the hands back … everyone talks about this separation, but the next move you see the body is no longer connected,” Latta said. “Now you are creating a path that is flat through the zone, [the barrel] will be perpendicular to the path of the pitch… energy is exhausted across the hitting plane instead of through the hitting plane.”

While there are different optimum swing paths for different types of hitters, we know more offense is generated through fly balls than ground balls.

In 2016, there were 3,079 doubles, 463 triples and 5,422 home runs via fly balls. When elevating the ball, batters hit .241 with a .715 slugging mark and a wRC+ of 139. In 2016, there were 988 doubles, 47 triples and zero home runs (as you might expect) via ground balls. Hitters batted .238 and slugged .258 on ground balls with a wRC+ of 27.

The National League’s MVP recorded a 0.67 GB/FB ratio last season, the fourth-best fly-ball ratio among qualified batters.

See Kris. Kris swings up. Kris is good. Swing up like Kris. pic.twitter.com/juWaJGyMzz — Chad Longworth (@clongbaseball) January 26, 2017

I asked Latta if he could change most hitters’ fly-ball tendencies.

He respond with a confident, emphatic one-word answer: “Absolutely.”

He has proof.

In the same facility where the “think tank” of hitting instructors gathered, in the same space where he has hosted curious major-league executives and hitting coordinators, he revamped the swings of Byrd and Turner.

Turner met Byrd when the former was playing as a reserve for the Mets in 2013. Byrd had spent the previous offseason rebuilding his swing with Latta, which I reported back in 2013. Byrd had serendipitously met Latta while looking for a place to hit near his offseason home after the 2012 season. After a winter of regular work with Latta, Byrd hit a then career-best 24 home runs with a career-best 132 wRC+.

Byrd went from an extreme ground-ball hitter earlier in his career, averaging nearly two ground balls to every fly ball from 2010 to -12, to posting a ratios of 1.06 in 2013, 0.92 in 2014, 1.17 in 2015 and 0.71 in 2016 in his brief tenure with the Indians before he was hit with a PED suspension.

“He was fast,” Latta said of a younger Byrd. “All his life, told to hit ball on the ground.” While Byrd’s improvement is viewed with suspicion due to his PED ties, he did benefit from changes to his swing path.

So in the winter of 2013-14, Turner, who lives in Southern California, began making a regular commute to Latta’s facility in search of a better swing. Since Turner broke into the majors in 2009, through the 2013 season, he’d produced a .260/.323/.361 slash line and 92 OPS+. His 162-game average for home runs? Five.

Said Turner to MLB.com: “It wasn’t something that just happened overnight. We did it five days a week for four months, trying to fix [my swing] and get to where I can repeat it.”

In Latta’ two nylon-netted cages, they began with flip drills. “Lots of flips,” Latta said. They advanced to a slider machine as spring training approached. Latta said they “built up” to live pitching, mastering adjustments before taking the next step. A key concept is finding a balance point, Latta says, to “create a launch from a good body-balance [position].” And it’s from that position, Latta says, where “the barrel is going to stay on the same path as the pitch for a longer time, it will always result in a natural upper cut.”

The following season, Turner produced a .340/.404/.493 slash line with the Dodgers in 322 plate appearances, producing a career-best 158 wRC+. Was it a fluke? Hardly. In 2015, Turner hit a career-best 16 home runs and produced a .294/.370/.491 slash line and 142 wRC+. Last season, Turner continued to hit, posting a career-best 27 home runs and a 124 wRC+.

While with the Orioles and Mets early in his career, Tuner’s GB/FB ratio hovered between 2.00 and 1.45 per season. In 2015, it fell to an an even 1.0 mark; last season, to 0.9.

Consider some video evidence of the Old Turner from 2012:

And the New Turner in 2016:

The relationship between fly balls and power is strong. Consider the batted-ball tendencies of J.D. Martinez as an Astro in 2012 and 2013. Martinez posted GB/FB ratios of 1.64 and 1.30 in those season, respectively. In his breakout 2014 season with the Tigers, after changing his swing plane, Martinez posted a 1.1 ratio, then a 0.79 rate in 2015, and 1.17 last season. After sub-100 wRC+ marks in 2012 and 2013, Martinez has posted marks of 154, 137 and 142 in three consecutive seasons.

What’s interesting about the improvement from Byrd, Donaldson, Martinez, Turner — and, to a lesser extent, Matt Joyce’s breakout — is they followed a similar formula: they worked with outside, independent hitting coaches and they began to lift pitches and drive pitches more often. This is what Joyce told me last season after he went from a non-roster invitee to making the team, and later earned a two-year deal with he A’s this offseason:

“You read things about Donaldson and Tewksbary, they are trying to get you on plane with the ball and stay on that plane… Ideally you want to create the most bat-speed as possible, get your swing on the same plane (as the pitch), and stay in the zone on the path to the ball as long as possible.”

Said Latta: “Most people labor under the idea that everything at the big leagues is the best it can be and there is nothing better than that… There is a lot of stuff out there that needs to change.”

Not all major-league hitters, or organizations, adhere or adopt to this philosophy of hitting down on the ball, as Eno Sarris reported back in 2015, but Latta says far too many amateur and professional players he encounters – he works with 24 professional hitters – are taught to swing down.

So why aren’t we seeing more fly balls? Why aren’t we seeing more adopt the philosophies shared by Latta?

Latta summarized much of it through one word: “Fear.”

One of his clients, a Double-A player, called him fighting back emotion because of the pressure being applied from his minor-league coaches to use a conventional approach versus an uppercut swing plane. Latta notes young players are at “the mercy” of a coaching staff. Latta says there are errant organizational hitting philosophies.

“Even executives – not even in the coaching ranks – have opinions,” Latta remarked. “Do you know how dangerous that is?” Latta said as an outsider, as a private instructor, he has the advantage of not having to fear for his job if he deviates from an organizational philosophy.

Moreover, the term “uppercut” carries a negative connotation with young players who have been taught to hit with a level swing, to chop down at the pitch, to get from Point A to Point B as quickly as possible. Swings are also very personal and prized.

“It’s gotta be done at the grass-roots level,” Latta said. “Everything they hear from 5 years old and up, you take a step back and say ‘This is why there is big a disconnect.’

“The generation of [amateur] hitters I’m teaching now are going to hit [pitches] in triple digits. It’s the reality. Triple digits are here… Any inefficiency in the swing is going to be more pronounced. We have to be more efficient.”

Part of the issue is hitters have not had the same tools to quantify their swings and skills like pitchers. Pitchers have had PITCHf/x since 2008. While HITf/x provided some insights, the industry has only two years of more comprehensive Statcast data, and perhaps some small advancements were made in the second year of the Statcast Era.

Consider this chart created by Bill Petti for this Sarris piece on the power of suggestion in December. There were slightly more optimum launch angles last season:

Latta said it’s incumbent on players to be curious and intellectual about the craft.

One of my favorite stories from last spring was talking to then Pirates’ non-roster invitee Cole Figueroa – who made the team – about his beliefs in swing philosophy. Figueroa is now working in the Tampa Bay front office.

He recounted a story about how when he had been in a different major-league camp earlier in his career. He’d heard a prominent player and the club’s hitting coach discussing how to create backspin through a chopping-wood approach. Figueroa approached him later in the clubhouse, and the roster hopeful explained to the positional-player regular how he had it all wrong.

“Figueroa said this idea of backspin was a myth, the swing plane he was using was not optimal. He explained what he really wanted to do is hit the ball as squarely as possible with a slight upper cut… He had the science to prove it: a Dec. 2014 study by University of Illinois professor, Dr. Alan Nathan, showed spin has little effect on batted ball distance.”

So why aren’t more hitters aware of this or listening to those who are? Why were more balls not being hit into the air in 2016?

“You see a Donaldson, you see a Turner, you hear people talking a little more. Now you can quantify [quality of contact)… But it’s still a small movement,” Latta said. “The results speak for themselves, but you are taking on 100 years of thought.”