DALLAS - First came the knockout, the hit to the head from either an elbow or another person's head - really, he's still unsure - that left 17-year-old Tommy Lamberth lying unconscious on the club soccer tournament field.
Then came the trip to the emergency room for 13 stitches above his left eye and two soccer practices the next week.
Soon came the anxiety and panic attacks. A few years later came the discovery of an irregular spot on his brain that likely developed, his doctor said, because of repeated hits to the head as a youth soccer player.
One thing that never came? A specific concussion diagnosis.
For the former Dallas Lake Highlands soccer player and current Richardson (Texas) Pearce boys soccer assistant coach, the quick return and disregard for ensuing headaches and dizziness was the norm when his accident occurred in the early 2000s.
But medical advancements and societal education about the consequence of head injuries has since advanced, and spreading awareness about the frequency of concussions in soccer has become a priority for experts in the field.
National, state and local statistics show soccer presents some of the highest concussion rates in youth sports.
While the soccer data trails football in most studies and often in media attention, Lamberth's long-term mental health fallout and new perspective as a coach underscores the dangers, caution and progress involved with concussions in the sport.
"Concussions weren't on my radar at all growing up, and why would they be?" Lamberth said. "It wasn't something that was talked about very much. The symptoms were so generic, like headache, dizziness. It's like, well that could be anything, so how do you ever know?"
Many times during high school soccer games, Lamberth felt dizzy and lightheaded, fought headaches.
"I'm probably just dehydrated," thought Lambert, who graduated from high school in 2004. "I haven't had enough water."
It's more likely he suffered from signs of a concussion, according to research over the past 15 years.
In the latest National High School Sports-Related Injury and Surveillance Study (2017-18) - which researches the rate of injuries in high school sports practices and competitions nationally - football (31.4 percent), girls soccer (24.5 percent) and boys soccer (16.3 percent) had three of the four highest percentages of concussions in each sport's respective injury totals.
Volleyball (18.6 percent) ranked third in concussion percentage among the nine sports the study considered, but the sport's total participation and injury rate was significantly lower than football and soccer.
In Texas, the UIL's partnership with UT-Southwestern to create a statewide high school sports concussion registry (ConTex2) shows soccer (30 percent) has the highest percentage of concussions among all girls sports, according to a recent update to the medical advisory committee on data 7 percent of state high schools have voluntarily reported.
Football led with 79 percent of all reported boys' sports concussions; soccer was second at 7 percent.
An independent study this spring by The Dallas Morning News showed similar trends with total football and soccer concussions leading boys and girls' sports, respectively.
In the study, which gathered data from 71 schools who replied to public records requests by April 10, girls soccer concussions (747) almost doubled boys soccer's total (405) between 2015 and 2019. Football led all sports with 2,315 in that span.
But much like the voluntary statewide numbers supplied to the UIL, the local feedback isn't complete.
Districts did not provide information about respective team size and total participants. Some couldn't or declined to separate concussion occurrences by gender. Others didn't keep records in certain years or included an "unknown" category.
Not all concussions included in the responses occurred during UIL-sanctioned activity because any students who are athletes and suffer concussions have to participate in the return-to-play protocol.
Still, the data reflects concerns of officials.
"I think this is a red flag that we have to get the answers to," UT-Southwestern's Dr. Hunt Batjer, who's involved in the UIL's medical advisory committee and ConTex concussion studies, said of soccer. "Make the sport safer."
About a year after his on-field accident, Lamberth was enjoying a celebratory graduation dinner with family when he started to sweat. His heart raced. He felt out of breath and flushed. He needed to get up.
The scenario happened twice during the meal.
That was one of the first panic attacks Lamberth remembered. Soon they became a consistent part of his life.
It took a few years of consulting with mental health and medical professionals before he recognized a connection between the collision and ensuing onset of anxiety.
A concussion, he then learned, doesn't always end when the headaches subside.
That's a mindset many coaches in the Dallas-area have adopted in recent years.
Allen boys soccer coach Kim Fullerton emphasizes the importance of weight room training to ensure his players are strong enough to withstand physicality in games. He teaches proper heading technique - meeting the ball on the forehead, not to the top or the temple - to eliminate unnecessary force.
Frisco Wakeland girls soccer coach Jimmie Lankford pulled a player from practice a few weeks ago when she became dizzy after heading the ball. She felt fine about a half-hour later, Lankford said, but he wouldn't allow her to return until she saw a doctor.
"We couldn't determine if she was dehydrated or she just hadn't had breakfast that morning or already had a headache," Lankford said, "but she went to the doctor and was cleared, so we're just really cautious.
"I tell them, soccer is a game. It's fun. But the brain is something that's forever."
Lamberth had read about late NFL players' post-mortem diagnoses of chronic traumatic encephalopathy (CTE) - a degenerative brain disease via repeated head trauma - and their families connecting changes in mood and behavior to brain damage.
His own realization came in an examination room in early 2012, just after he unexpectedly collapsed at work. The doctor projected a copy of Lamberth's recent brain scan on the screen and pointed.
"You see this?" Lamberth remembered the doctor asking before explaining the dime-sized dark spot wasn't supposed to be there.
"That's probably from head injuries and that's probably the reason why I had a sudden on-set of anxiety and having panic attacks," Lamberth said. "You can't definitely say one way or another because there's so much we don't know, but he said he felt pretty confident they were linked together."
The feedback served as a reminder to Lamberth to protect his players as a coach.
Texas has aimed for all to do the same.
The ConTex2 study will make concussion reporting mandatory for all Class 6A schools in the 2019-2020 school year, and Batjer expects increased collection should offer more substantial analysis.
From there, Batjer hopes possible rule changes or equipment suggestions can emerge, similar to how the UIL has mandated a modern tackling certification for all football coaches as the sport's concussion issues have become mainstream discussion.
The UIL currently allows soccer players the option to wear soft, protective headgear. U.S. Youth Soccer, which governs most of the country's leagues for kids and teenagers, in 2015 banned heading for players under 11.
"We can design approaches," Batjer said. "Let's say if all the girls who escaped concussions in soccer wore helmets, well maybe there's a message there."
In the last decade, all 50 states have passed rules or laws to address concussions in youth sports.
In 2011, the Texas state legislature passed House Bill 2038, known also as Natasha's law, to require school districts to create concussion oversight teams, which include a physician, and to establish return-to-play protocols that require a physician's evaluation.
It also spurred mandatory two-hour concussion education training for all high school sports coaches and athletic trainers
Lamberth said he's learned much from the program, even after his years-long process of understanding head-injury ramifications, and has seen it influence Pearce's control.
Pearce doesn't hesitate to sit players during a game if coaches or trainers suspect a concussion. Lamberth said some players have relayed verbal clearance from doctors, but Pearce's staff requires written permission to return.
Lamberth, in most instances, takes a simple approach.
He defers every decision and interaction to the district's athletic trainers because he's too familiar with the lingering impact of not having proper caution and care.
"There's been a very big culture shift within athletics to where they are much more aware of not only concussions but the symptoms and education and the awareness of it," Lamberth said. "Things like that didn't exist when I was playing."
Visit The Dallas Morning News at www.dallasnews.com