78% Showed Concussion Signs: The JAMA Study That Put Power Slap on Trial
A peer-reviewed study published in JAMA Surgery examined 333 slaps from the first televised season of Power Slap and found that 44 of 56 contestants — 78% — showed at least one visible sign of concussion, and 20 of them showed signs of a second concussive impact before recovering from the first. It is the first formal medical analysis of the sport Dana White launched in 2023, and it moves the safety debate around slap fighting from opinion to published data.
The findings landed on a sport built for virality. Power Slap knockout clips routinely rack up tens of millions of views, and the format's appeal — two competitors trading undefended, full-power strikes to the face — is exactly what the researchers flagged as the danger.
What the Study Found
The research was led by neurologist Raj Swaroop Lavadi of the University of Pittsburgh, working with the VA Pittsburgh Healthcare System. The team reviewed video of 333 slaps involving 56 contestants from Power Slap's first season and scored each strike and sequence for recognized visible signs of concussion.
The headline numbers:
- 44 of 56 contestants (78%) showed at least one sign of concussion.
- 20 contestants displayed signs consistent with a second impact — taking further head trauma before recovering from an earlier blow.
- 97 of 333 slaps (roughly 30%) produced visible concussive signs.
- Contestants who showed concussion signs went on to lose the sequence about 75% of the time, linking the visible neurological signs directly to fight outcomes.
The most common signs were loss of motor coordination, slowness to stand, and a blank or vacant stare. Neuroscientist and former wrestler Christopher Nowinski, reviewing footage, documented one contestant exhibiting a "fencing posture" — a rigid, involuntary arm position that is a recognized marker of significant traumatic brain injury.
Why Slap Fighting Is Mechanically Different
Combat sports all carry head-trauma risk, but the study's authors singled out what makes slap fighting distinct. In boxing or MMA a fighter can slip, block, roll with a punch, or simply move. In a Power Slap bout, the defender must stand still, keep their hands down, wear no headgear, and absorb an opponent's full-force strike to the unprotected lower face without flinching. Every element that a trained fighter uses to reduce the force of a blow is stripped out by the rules.
That is the crux of the medical concern: the format does not just permit head trauma, it structures the entire competition around delivering it cleanly. The authors concluded that slap fighting "may induce traumatic brain injury in contestants, with potential for long-term consequences."
The Study's Own Limits
The research relied on visible signs of concussion scored from broadcast video, not on clinical diagnosis, brain imaging, or post-fight neurological exams. A vacant stare or a delayed stand-up is strong circumstantial evidence of a concussion, but it is not a confirmed medical diagnosis, and the authors were explicit about that boundary. The study establishes a pattern and a prevalence; it does not measure long-term outcomes for individual fighters, which would require years of follow-up.
That caveat matters for honest reporting. What the data shows is that concussion signs are common and, in a meaningful share of bouts, repeated. What it does not yet show is the lifetime cost.
How It Fits a Growing Safety Record
The JAMA study does not arrive in a vacuum. Questions about slap fighting's safety have followed the sport since its launch, and the concerns are documented rather than hypothetical — the death of Polish competitor Artur Walczak after a slap-fighting event remains the starkest example, covered in our report on the Power Slap death that reframed the risk debate. Medical and legislative scrutiny has been building alongside the viewership, a story we track in our piece on slap fighting reaching the level of congressional and regulatory attention, and the broader question of the format's danger is broken down in our explainer on whether Power Slap is dangerous.
For readers new to the sport itself, what Power Slap is and how it works covers the ruleset the study was measuring. The through-line across all of it is consistent: the entertainment value and the injury mechanism are the same thing.
What Happens Next
A single study will not shut down a sport with Dana White's backing and a deep, growing talent pool. But peer-reviewed prevalence data changes the terms of the argument. Athletic commissions weighing whether to sanction slap events now have a citable figure. Broadcasters and sponsors evaluating association risk have one too. And the sport's defenders can no longer answer safety questions purely with anecdote, because the other side now has a number: 78%.
Power Slap's competitors sign up knowing what the format is. The open question the JAMA study sharpens is not whether individual fighters consent to the risk — it is whether a competition engineered to land clean, undefended head trauma can be made meaningfully safer without ceasing to be the thing that made it go viral.
