In addition to reckless and intentional action that results in injury, amateur coaching decisions, recommendations, and strategies can lead to injuries and can be considered elements of avoidable risk, constituting a breach of duty based on the expectations of the participants (Fitzgerald 2005). Breach can also occur, of course, through the intentional or reckless behavior of sports participants that shows a disregard of the basic rules and expectations of the sport beyond mere negligence (Saywer 1997; Abramson et al. 2010). Sports physicians may also be found in breach of their medical duties if pre-participation screenings are not thorough enough (Kane & White 2008). Heat illnesses, as might be expected at this point, almost never constitute a breach of duty, as it is wholly within the participant's power to assess and respond to their condition during any activity, whether an organized sports activity or otherwise. Likewise, spinal cord injuries and concussions could possibly result from a breach of duty, as in a tackle occurring in a generally non-contact sport such as baseball, but again a case-by-case assessment of such injuries is necessary, and the extent of the injuries themselves cannot constitute evidence of any breach, recklessness, or intentionality in the injurious act.

Assumption of Liability and Risk

The most profound and far-reaching element of legislation and case law regarding sports injuries is the desire to encourage the active participation in sports activities, and it is for that reason that ordinary standards of care and negligence have been deemed legally insufficient standards of liability, with the participants themselves assuming liability for any and all inherent and foreseeable risks that might arise out of their participation (Sawyer 1997; Kane & White 2008). In most cases, the assumption of risk is implied in participation...

This is referred to in law as the primary implied assumption of risk, and generally prevents liability for injuries from being attached to other enthusiastic and non-reckless participants in the sporting activity (Abramson et al. 2010).
This also makes it abundantly clear why heat stroke and exhaustion are solely the responsibility of each individual participant in a sport; just as someone performing maintenance on their home assumes responsibility for their exposure to the elements, so does a sports participant. Though spinal cord injuries and concussions are perhaps more serious and less expected -- and less preventable -- injuries, in contact sports such as football and soccer the potential for such injuries should be evident to every participant, and their participation in these sports implies their assumption of risk that these injuries might arise out of normal game play.

References

Abramson, a.; Smith, J. & Waldsmith, R. (2010). "The law of assumption of risk in sporting activities." Sports injury lawyer.

Fitzgerald, T. (2005). "The inherent risk doctrine, amateur coaching negligence, and the goal of loss avoidance." Northwestern University Law Review (2005) 99(2), pp. 889-930.

Kane, S. & White, R. (2008). "Medical Malpractice and the Sports Medicine Clinician." Clinical orthopaedics and related research 467(2), pp. 412-9.

Lazaroff, D. (1990). "Torts & (and) Sports: Participant Liability to Co-Participants for Injuries Sustained during Competition." University of Miami entertainment and sports law review pp. 191-225.

Sawyer, T. (1997). "Torts, Negligence, Duty, and Sports Injuries." The Journal of Physical Education, Recreation & Dance 74(4),…