Uncover the complexities of California's 'primary assumption of risk' doctrine. Know when you can—and can't—take legal action for injuries in sports and high-risk activities.

By Mark Kiefer, Esq.

It is that time of year when the intrepid come out of winter hibernation and declare that it is time they get some exercise! It is all well and good until Joey enrolls in a martial arts class only to get his block knocked off like a Rock’em Sock’em Robot. Then Joey wants to sue the pants off someone (his coach, the dojang, the one who knocked his block off), but how far will Joey get?

You may know the General Rule: all persons have a duty to use due care to avoid injury to others and may be held liable if their careless conduct injures another person. California Civil Code, Section 1714. But in 1992, in a touchstone opinion that has been repeatedly cited to limit recovery by plaintiffs like Dojo Joey, the California Supreme Court announced, “In some situations, however, the careless conduct of others is treated as an ‘inherent risk’ of a sport, thus barring recovery by the plaintiff.” Knight v. Jewett (1992) 3 Cal.4th 296, 316. This rule is known as “primary assumption of the risk” in sports.

It turned out to be such a good idea that the Judicial Council of California Advisory Committee on Civil Jury Instructions came up with not one but three jury instructions concerning sports (CACI 470-472) in 2003 and 2013 and topped that off with another concerning risky occupation (CACI 473) in 2017. The rule now protects co-participants, instructors, trainers, coaches, facility owners and operators, and event sponsors.

“Assumption of Risk” Has Been Around a While

But this was not a new idea. In 1929, leading legal light and future U.S. Supreme Court Justice Benjamin Cardozo addressed the claim of a man who hurt his bum in a fall on “the Flopper,” a Coney Island amusement park attraction where one tried to keep one’s balance while standing on a moving belt (yes, this was the decade of the 1920s). Ruling in favor of the venue, the unsympathetic Justice wrote, “The timorous may stay at home.” Murphy v. Steeplechase Amusement Co. (1929) 250 N.Y. 479. He might just as well have written, “Rub some dirt on it and walk it off.”

In the Knight v. Jewett case cited above, friends were playing a touch football game during the 1987 Super Bowl. An overzealous male player knocked a female player down and stepped on her hand. The Court said, “In the heat of an active sporting event like baseball or football, a participant’s normal energetic conduct often includes accidentally careless behavior.” Knight v. Jewett (1992) 3 Cal.4th 296, 318.

The rule is not limited to classic sports; the rule has reached into the world of cheerleading. When a cheerleader was not caught by her fellows, the Court wrote: “It is not unusual for modern cheerleaders to perform gymnastic stunts which may catapult a cheerleader many feet into the air. What goes up, must come down. This includes cheerleaders. Whenever gravity is at play with the human body, the risk of injury is inherent.” Aaris v. Los Virgenes Unified School Dist. (1998) 64 Cal.App.4th 1112, 1114-1115.

What is “Inherent Risk”?

The test for inherent risk has been articulated this way: “A risk is inherent in a sport if its elimination (1) would chill vigorous participation in the sport, and (2) would alter the fundamental nature of the activity.” Sanchez v. Hillerich and Bradsby Co. (2002) 104 Cal.App.4th 473

Certainly, one would want to encourage mechanical bull riding. In a very recent and exciting opinion, one California Court said, “[a]lthough no published California appellate opinion has yet addressed the inherent risks of riding a mechanical bull, courts in other jurisdictions have…Based on these cases from other jurisdictions, the evidence in the summary judgment record, and common sense, we hold mechanical bull riding is a type of activity covered by the primary assumption of risk doctrine: it is done for the thrill, requires physical exertion as well as skill, and carries a risk of injury. Like riding a horse, riding a mechanical bull has certain inherent and obvious risks, most notably falling or being thrown from the device.” Murillo v. Diego (2023) 2022 WL 4232040 (Court of Appeal, Second District, Division 5; not certified for publication).

Are There Exceptions to Assumption of Risk?

But liability may still attach if someone acts to artificially and unnecessarily increase the inherent risk in the activity: a jockey was instructed to ride an injured horse on an unsafe, rocky track and in a direction opposite from that in which horses are normally ridden. The horse stumbled on the track and fell, injuring the jockey. Tan v. Goddard (1993) 13 Cal.App.4th 1528, 1531. Summary judgment should not have been granted where there was an issue of whether a swim coach’s failure to instruct a student on shallow-water diving increased the risk inherent in the sport of competitive swimming and caused the diver to break her neck. Kahn v. East Side Union High School Dist. (2003) 31 Cal.4th 990, 1018.

Charlie & Lucy – Assumption of Risk?

Considering the above, how would you decide on the following case? Lucy tees up a football for a kick. Charlie Brown runs up to kick the football. But just as he is about to kick the football, Lucy snatches it away. Charlie Brown flies up and crashes to the ground. Did Charlie Brown assume a risk inherent in playing football (with Lucy), or did Lucy artificially and unnecessarily increase the risk? We think that, like Joey at his martial arts dojo, the answer just depends.


Mark Kiefer, Special Counsel at BG+W Mark Kiefer is Special Counsel at Bradley, Gmelich + Wellerstein LLP. His practice focuses primarily on defending medical, legal, and other professionals in malpractice litigation. His experience in the healthcare industry also includes skilled nursing facilities, home health care, detox centers, emergency medical transport, and sexual misconduct matters.

Mark also has experience in premises liability, construction accidents, construction defects, toxic/environmental torts, product liability, transportation/trucking cases, business litigation, and a wide range of general civil liability matters. He has handled catastrophic personal injury and wrongful death claims involving significant exposures. Mark has trial experience and has both published and unpublished cases at the appellate and California Supreme Court level, including the landmark decision in Wilson v. Parker, Covert & Chidester (2002) 28 Cal. 4th 811, a case that is frequently cited in this area of the law. He is involved as a pro bono arbitrator for the Los Angeles Superior Courts.

Prior to joining BG+W, Mark was the Co-Managing Partner of the Los Angeles office of a statewide litigation firm. He served on the firm’s Board of Directors and was Co-Chair of the Firm’s Healthcare practice group. He is AV® Peer Review Rated by Martindale-Hubbell.