For the first time, the UFC has published an official concussion protocol for fighters.

The UFC Performance Institute released Tuesday a digital journal titled "A Cross-Sectional Performance Analysis and Projection of the UFC Athlete." The 484-page study uses data collected between 2017 and 2019 as reference material for mixed martial arts coaches and fighters. The resource, likely the most comprehensive study on MMA ever produced, includes the UFC's return-to-sport protocol following concussions or traumatic brain injuries (TBIs).

The journal is the second volume of findings from the UFC Performance Institute (UFC PI), a facility adjacent to the UFC headquarters in Las Vegas that houses MMA training, medical and nutrition resources as well as strength and conditioning workouts. The UFC PI opened in 2017, and its first volume of research was published in 2018.

"The goal is we really want to support the ongoing development and performance behaviors and activities in the MMA gyms in the combat community globally," said Duncan French, the UFC's vice president of performance. "We are slowly aggregating our own insights and our information here in the Performance Institute, and we want to share that. We don't want the PI to become an ivory tower where the information is only retained for a discrete 600 roster of fighters."

Perhaps most notable in the UFC PI's new journal is the five-stage concussion protocol for fighters to return to action.

The UFC's return-to-sport protocol is similar to the NFL's concussion protocol, beginning with up to two days of rest, then advancing into two stages of no-contact workouts. The UFC wants fighters to use the concussion assessment tool -- essentially a questionnaire about symptoms -- called the SCAT5. As symptoms improve, fighters can go from no-contact workouts -- aerobic and strength exercises, as well as technique drills -- to moderate contact workouts, including MMA drills with "little risk of any head contact," such as grappling positional routines.

The final stage includes a return to live sparring, and the UFC PI recommends starting with one sparring session per week with no more than three rounds of five minutes, then "progressively add rounds over the course of four weeks until you reach two full sparring sessions of five rounds in each session." Returning to full contact requires clearance by a physician.

The UFC is unique compared to contact team sports because fighters are independent contractors and return home after competition to their local coaches and doctors. But it is the promotion's hope that this published concussion protocol becomes standardized in MMA all over the world.

"For brain injuries like concussion, even if you are feeling symptom-free, a fighter should go through all stages of a return-to-sport protocol to ensure a full brain recovery," the journal reads. "Further, resuming activity too quickly, especially in contact sports like MMA, not only increases the risk of subsequent musculoskeletal injuries and longer recovery times but also further concussions (e.g., second-impact syndrome) which can lead to chronic neurological conditions, permanent disability and death."

Other sections of the journal -- which is split up into strategy; offseason; training camp; fight week and competition; and postfight and recovery parts -- details how fighters should manage concussion symptoms and how nutrition can affect symptoms. A standardized assessment of concussion study in the journal shows that male UFC fighters experience concussion symptoms that are more than six times worse than the general population, and female UFC fighters experience concussion symptoms more than seven times worse than average.

"Now, we need to do more work to understand how we can potentially support the ladies if they do have a concussion," French said. "Because that method, that approach to return to play following a concussion in females might need to be different."

In addition to all the data published on concussions, the journal offers advice for fighters on choosing which weight class they compete in, how those weight classes win fights and proper methods of weight cutting, considering multiple variables such as travel.

From a competition standpoint, the UFC PI's data shows that statistically, fighters who throw more strikes than their opponents win in every weight class. And there were 5% more knockouts and 8% more submissions in the UFC's smaller cage (25 feet) compared to its bigger cage (30 feet) between 2017 and 2019. Only 39% of fights in the smaller Octagon went to decision, compared to 51% in the bigger Octagon.

"We truly now feel [this journal] is the most contemporary and comprehensive reference material in MMA," French said. "It's almost like a textbook. We want people to use it as a point of reference."