"As a general rule, each person has a duty to use ordinary care and 'is liable for injuries caused by his or her failure to exercise reasonable care in the circumstances.' " (Parsons v. Crown Disposal Co. (1997) 15 Cal.4th 456, 472, citing Rowland v. Christian (1968) 69 Cal.2d 108, 112, 70 Cal. Rptr. 97; Civ. Code, 1714.) In the context of active sports, however, the scope of this duty is limited by the assumption of risk doctrine. (Calhoon v. Lewis (2000) 81 Cal.App.4th 108, 115.) In Knight v. Jewett (1992) 3 Cal.4th 296, the Supreme Court considered the proper application of the assumption of risk doctrine in light of its adoption of comparative fault principles in Li v. Yellow Cab Co. (1975) 13 Cal.3d 804, 119 Cal. Rptr. 858. (Knight, at pp. 299-300.) The court "distinguished between (1) primary assumption of risk-'those instances in which the assumption of risk doctrine embodies a legal conclusion that there is "no duty" on the part of the defendant to protect the plaintiff from a particular risk'-and (2) secondary assumption of risk-'those instances in which the defendant does owe a duty of care to the plaintiff but the plaintiff knowingly encounters a risk of injury caused by the defendant's breach of that duty.' Primary assumption of risk, when applicable, completely bars the plaintiff's recovery. The doctrine of secondary assumption of risk, by contrast, 'is merged into the comparative fault scheme, and the trier of fact, in apportioning the loss resulting from the injury, may consider the relative responsibility of the parties.' Whether primary or secondary assumption of risk applies 'turns on whether, in light of the nature of the sporting activity in which defendant and plaintiff were engaged, defendant's conduct breached a legal duty of care to plaintiff.' The test is objective; it 'depends on the nature of the sport or activity in question and on the parties' general relationship to the activity' rather than 'the particular plaintiff's subjective knowledge and awareness . . . .' " (Cheong v. Antablin (1997) 16 Cal.4th 1063, 1067-1068, citing Knight, supra, 3 Cal.4th at pp. 308, & 313-315.) In Knight, the court held the primary assumption of risk doctrine barred a woman from recovering for personal injuries she sustained in a touch football game. The court concluded "that a participant in an active sport breaches a legal duty of care to other participants-i.e., engages in conduct that properly may subject him or her to financial liability-only if the participant intentionally injures another player or engages in conduct that is so reckless as to be totally outside the range of the ordinary activity involved in the sport." (Knight, supra, 3 Cal.4th at p. 320.) The court explained that "although defendants generally have no legal duty to eliminate (or protect plaintiff against) risks inherent in the sport itself, it is well established that defendants generally do have a duty to use due care not to increase the risks to a participant over and above those inherent in the sport." (Id. at pp. 315-316.) The Knight court also explained that "vigorous participation in certain sporting events likely would be chilled if legal liability were to be imposed on a participant on the basis of his or her ordinary careless conduct. . . . Even when a participant's conduct violates a rule of the game and may subject the violator to internal sanctions prescribed by the sport itself, imposition of legal liability for such conduct might well alter fundamentally the nature of the sport by deterring participants from vigorously engaging in activity that falls close to, but on the permissible side of, a prescribed rule." (Knight, supra, 3 Cal.4th at pp. 318-319.) An activity falls within the primary assumption of risk doctrine if it " ' "is done for enjoyment or thrill, requires physical exertion as well as elements of skill, and involves a challenge containing a potential risk of injury." ' " (Calhoon v. Lewis, supra, 81 Cal.App.4th at p. 115; Bjork v. Mason (2000) 77 Cal.App.4th 544, 550; Record v. Reason (1999) 73 Cal.App.4th 472, 482.)