ASU Hockey Collapse: Ex‑Green Beret Led Outdoor Workout; University Promises Thorough Review of Training and Medical Response

Table of Contents

1. Key Highlights
2. Introduction
3. Timeline of the workout and collapse
4. Who is Tim Ziesel and why was he on the field?
5. The athlete: Matthew Mayich — profile and condition
6. University response and the scope of the review
7. Medical context: heat illness, exertional cardiac events and sport
8. Oversight, medical staff responsibilities and NCAA guidance
9. Legal and liability considerations
10. Emergency response on college campuses: what the record shows and what was reported
11. Risk factors in young athletes and preventive strategies
12. The broader conversation about outside trainers and "military‑style" workouts
13. Community reaction, support networks and the role of social media
14. Lessons for athletic programs: prevention, policy and culture
15. What investigators will likely examine next
16. Historical and international context: sudden collapses in sport
17. Transparency, family privacy and public expectations
18. Recommendations for athletes, coaches and campus health leaders
19. Community and cultural implications
20. Where the story stands now
21. FAQ

Key Highlights

• An ex‑Green Beret who ran an outdoor, military‑style workout for Arizona State University’s hockey team says he left before freshman defenseman Matthew Mayich collapsed; university officials have launched a review of the incident.
• The trainer’s attorney described the routine as moderate, said athletic staff and medical personnel were present, and emphasized the need for an objective investigation.
• Mayich remains hospitalized after an apparent cardiac event; the situation has prompted scrutiny of training oversight, emergency preparedness and the role of outside volunteers in collegiate athletics.

Introduction

A routine preseason workout at Arizona State University on Aug. 20 escalated into a crisis when a sophomore hockey player collapsed and was rushed to the hospital with what team and family contacts describe as a cardiac event. The person who led part of that session, Tim Ziesel — a Special Forces veteran invited back by ASU coaches after running a similar drill in 2025 — has provided the first public account from someone who oversaw players at the start of the exercise. He says he departed the field about 20 minutes before the collapse.

ASU has declined to disclose details of the routine beyond confirming the student‑athlete remains hospitalized and that the university is reviewing the circumstances. That mix of limited institutional comment, eyewitness accounts, and the involvement of an outside volunteer with a military background has intensified public interest in procedures for team training, medical oversight and emergency response on college campuses. The story raises practical questions: who controls conditioning sessions, how are medical risks assessed during high‑intensity activity in warm weather, and what safeguards should be in place when non‑staff trainers work with student‑athletes?

This article reconstructs the known timeline, profiles the participants, explains the medical and policy context, examines legal and institutional responsibilities, and outlines best practices athletic programs should follow to reduce the risk of similar incidents.

Timeline of the workout and collapse

According to statements provided to The Arizona Republic and public records, the outdoor workout took place early on Aug. 20 at ASU’s Joe Selleh Track near Rural Road and Rio Salado Parkway, coinciding with the first day of fall classes. Tempe Fire Medical Rescue crews responded at 8:30 a.m. for a reported heat‑related illness; ambient temperatures were between 87 and 89 degrees at that time.

Tim Ziesel, identified by The Republic as the individual who led a portion of the session, says he completed about 45–50 minutes of exercises that included sprints, push‑ups, flutter kicks, and partner carries. He told a lawyer representing him, Buddy Rake, that later parts of the workout — involving medicine balls, for example — occurred after he had left the field. Rake said Ziesel departed before any players collapsed and did not personally observe anyone fainting or exhibiting distress.

Rake characterized the routine as moderate and asserted that head and assistant coaches and medical staff were present throughout. Approximately 20 minutes after Ziesel left, the player later identified in reports as sophomore defenseman Matthew Mayich suffered an apparent cardiac event and was transported to the hospital. He was later transferred to Barrow Neurological Institute and remained in a coma as of reporting.

ASU Athletic Director Graham Rossini declined to provide details to The Republic; university spokespeople said the institution was conducting a thorough review of the workout and circumstances surrounding the collapse. The university has not publicly named the athlete and cited privacy interests, though the player’s identity became known through reporting and public social media messages.

Who is Tim Ziesel and why was he on the field?

Tim Ziesel is a Scottsdale resident and a former U.S. Army Green Beret who has led volunteer military‑style conditioning sessions for collegiate athletes. ASU’s coaching staff invited him back for a second year after athletes responded positively to similar activities in 2025. Ziesel has led comparable sessions at other programs; an Arizona Christian University men’s basketball social post from 2022 thanked him for helping the team “learn more about what it means to be men of character, meekness, and integrity.”

Ziesel’s background includes service in the Navy and the Army, and he has publicly discussed his faith and recovery efforts after a serious motorcycle crash in 2023 that his attorney says caused long‑term cognitive and physical effects. He has spoken on podcasts about his military experiences and faith‑based outreach.

Rake, Ziesel’s attorney and former high school basketball coach, framed the workout as vigorous but not extreme, rating the conditioning as about a five or six on a 10‑point scale. He emphasized that water and medical staff were available and that the exercises complied with state and NCAA guidelines, while acknowledging the incident was “horrible” and warranted investigation.

The presence of a volunteer or outside trainer on a collegiate practice field raises questions about authorization, oversight and role delineation. Teams sometimes use guest instructors for specific skills, leadership training or nontechnical conditioning. Institutions typically require that those interactions conform to athletic department policies and be supervised by team coaches and health staff. The limited public information released by ASU leaves open whether formal authorization and supervision protocols were followed in this instance.

The athlete: Matthew Mayich — profile and condition

Matthew Mayich, a sophomore defenseman from Stoney Creek, Ontario, played junior hockey in the Ontario Hockey League with the Ottawa 67’s and spent a freshman season at Clarkson University in Potsdam, New York. He was part of a transfer class that helped ASU build a program ranked highly among transfer acquisitions in 2026. Mayich appeared in 34 games for Clarkson, scoring seven goals and eight assists in his freshman season, and was selected by the St. Louis Blues in the 2023 NHL Draft (sixth round, 170th overall). Drafted players retain NCAA eligibility while NHL teams hold signing rights.

After collapsing at the ASU track, Mayich was initially taken to a hospital and later moved to Barrow Neurological Institute, where public reporting said he remained in a coma. Family members and community supporters have organized daily prayer services; the Catholic community has led rosaries and called for privacy and support for the family. Messages from former teams and teammates circulated online, expressing concern and solidarity.

The specific medical cause of Mayich’s collapse — whether primary cardiac arrest, an exertional heat illness compounded by a cardiac event, an underlying heart condition, or another medical issue — was not publicly released by ASU or medical authorities. Health privacy laws and hospital policies commonly prevent institutions from disclosing diagnostic details without family consent.

University response and the scope of the review

ASU officials limited public disclosures to confirming that a student‑athlete collapsed during an outdoor exercise and that the university was reviewing the circumstances. Athletic Director Graham Rossini described the process on local radio as fact‑gathering rather than an adversarial investigation, saying the university was “reviewing the facts and understanding the scenario.”

ASU informed the public that medical and emergency personnel responded to the scene. Beyond that, the athletic department declined to explain the structure of the workout or who was authorized to lead conditioning sessions. Coaches and the team trainer did not respond to interview requests, and the university’s media relations office has been the main point of contact.

A thorough review of incidents like this typically examines: who organized and authorized the workout; whether the plan was documented and consistent with athletic department policy; whether medical staff were present and equipped; response time and the nature of on‑site interventions (including use of an automated external defibrillator, or AED, if cardiac arrest occurred); environmental conditions and acclimatization; and the athlete’s medical history and preparticipation clearance. The university’s stated commitment to review suggests administrators will consider these factors; however, public disclosure of findings often waits until the process concludes or the family consents.

Medical context: heat illness, exertional cardiac events and sport

When a young, otherwise healthy athlete collapses during conditioning, clinicians consider multiple possibilities: exertional heat stroke, cardiac arrhythmia or sudden cardiac arrest, structural heart disease (such as hypertrophic cardiomyopathy), electrical abnormalities (long QT syndrome, Wolff‑Parkinson‑White), myocarditis, or noncardiac causes such as vasovagal syncope. Exertion in high ambient temperatures increases risk for heat‑related illnesses; exertional heat stroke is a medical emergency characterized by central nervous system dysfunction (confusion or loss of consciousness) and core body temperature often exceeding 104°F (40°C) if untreated.

Distinguishing heat stroke from primary cardiac arrest in the immediate aftermath can be clinically challenging without access to hospital diagnostics. Emergency responders and on‑site medical personnel focus first on assessing breathing and circulation, initiating CPR and AED use if the athlete is pulseless, and rapidly transporting to definitive care. For heat stroke, immediate whole‑body cooling — ideally with cold water immersion — is the critical on‑site intervention while arranging rapid transport.

According to the report of responding Tempe Fire Medical Rescue units, the incident was treated initially as a heat‑related illness, consistent with calls to the scene and the temperature at the time. The Arizona Republic described Mayich’s event as an “apparent cardiac event,” and subsequent transfer to a neurological institute suggests the collapse produced severe neurologic consequences consistent with prolonged hypoxia or other critical injury.

Public reporting did not specify whether an AED was used at the scene, whether CPR was performed by staff or bystanders, or the precise timeline between collapse and advanced life support — each of which matters for prognosis.

Oversight, medical staff responsibilities and NCAA guidance

Collegiate athletic programs operate under institutional policies and, for many sports, under NCAA best‑practice guidelines relating to athlete health and safety. These typically include preparticipation medical evaluations, emergency action plans (EAPs) for all venues, heat‑illness mitigation strategies (hydration, acclimatization protocols, and environmental monitoring), and requirements for sports medicine staff to be present at practices and competitions.

An EAP should specify roles and responsibilities for coaches, athletic trainers, EMTs and other responders; identify location of emergency equipment, including AEDs; and define communication channels for contacting emergency medical services. Heat‑illness protocols generally recommend monitoring Wet Bulb Globe Temperature (WBGT) where feasible, modifying or canceling outdoor activity at specified thresholds, and ensuring access to rapid cooling. Many institutions have policies restricting who may lead conditioning activities and requiring supervision by credentialed athletic staff when student‑athletes exercise.

When outside volunteers participate in team activities, best practice requires clear authorization and supervision. Volunteers may bring valuable expertise, but their role should be integrated with the athletic department’s medical supervision to prevent miscommunication or gaps in duty of care. The presence of certified athletic trainers, team physicians or other licensed clinicians at workouts is a critical protective element.

ASU’s review will likely examine whether the workout adhered to EAP and heat‑illness guidance and whether the presence and roles of coaches, trainers and volunteers were clearly defined.

Legal and liability considerations

When a student‑athlete suffers a catastrophic medical event during a university‑sanctioned activity, legal issues often arise around negligence, duty of care and institutional responsibility. Liability can hinge on whether the university and staff breached standards of care reasonably expected in similar circumstances.

Key legal questions include:

• Was the workout an officially sanctioned athletic department activity or an informal gathering?
• Who authorized the outside trainer to lead the session and under what conditions?
• Were medical personnel on site and equipped to respond to cardiac or heat emergencies?
• Did coaches and staff follow written policies for environmental monitoring, hydration breaks and medical oversight?
• Were emergency action plans in place and followed?

University institutions generally have indemnification procedures and risk‑management policies to address these cases. Families may pursue civil claims if evidence suggests negligence or deviation from accepted medical and coaching standards. Conversely, thorough, well‑documented adherence to policies and rapid emergency response can mitigate institutional liability.

The trainer’s attorney emphasized the presence of coaches and medical staff and described the workout as moderate. That representation frames Ziesel as an invited volunteer who did not witness the collapse. Investigators will seek records, witness statements and timeline data to determine whether the legal duty of care was met.

Emergency response on college campuses: what the record shows and what was reported

Public reporting confirms Tempe Fire Medical Rescue arrived at the Joe Selleh Track shortly after 8:30 a.m. The presence of trained first responders at the scene is consistent with rapid escalation to emergency medical services. What is not public are crucial clinical details: whether CPR or AED use occurred on the field, the length of any pulseless interval, whether whole‑body cooling was employed, and how quickly advanced life support commenced.

Universities typically expect immediate, on‑site medical care from certified athletic trainers or campus EMS until handoff to local emergency services. Delays or confusion at this stage can be decisive for outcomes following cardiac arrest or severe heat stroke. Documenting and rehearsing emergency drills, ensuring AED availability at outdoor facilities, and clarifying chains of command reduce response times and errors.

The university’s stated review should examine audio, video and witness timelines. If protocols were followed, the review will likely affirm compliance; if not, the review will identify corrective steps.

Risk factors in young athletes and preventive strategies

While sudden cardiac arrest in young athletes is rare, it remains the leading cause of death during sport for athletes under 35. The risk rises under certain conditions: preseason conditioning, sudden increases in training intensity, environmental heat, inadequate acclimatization after time away, and unrecognized cardiac pathology. Viral myocarditis, sometimes following common viral infections, has been implicated in sudden cardiac arrest among young athletes in the months following illness.

Preventive strategies that athletic programs should employ:

• Preparticipation evaluations that identify concerning medical history or symptoms (syncope, chest pain, unexplained shortness of breath).
• Screening tools that include targeted history and physical; ECG screening is practiced variably across programs and countries, with debate regarding sensitivity and logistics.
• Structured acclimatization plans for athletes returning to intense activity after offseason or travel.
• Environmental monitoring and dynamic adjustments to practice intensity or duration based on WBGT and heat index thresholds.
• Clear hydration protocols and scheduled rest breaks.
• On‑site medical personnel for all high‑risk sessions and a standing EAP practiced regularly by staff.
• Ready access to AEDs and training for coaches and staff in CPR and AED use.
• Policies that control the use of outside volunteers and require their integration with medical and coaching staff.

Institutions that implement these measures reduce the likelihood of catastrophic events and improve survival when emergencies occur. Several high‑profile cases illustrate the impact of preparedness: immediate CPR and AED use saved lives in incidents such as the 2021 collapse of NFL player Damar Hamlin during a game, and early defibrillation is a consistent predictor of survival after sudden cardiac arrest.

The broader conversation about outside trainers and "military‑style" workouts

Teams sometimes recruit external instructors — military veterans, strength coaches, or motivational speakers — to provide character‑building sessions or alternative conditioning. Such programs can boost team cohesion and resilience. Yet these benefits require that the athletic department retain authority over content, safety protocols and medical oversight.

Military‑style conditioning often emphasizes high rep body‑weight work, running, partner carries and competitive drills. That training can be safe when scaled to athletes’ conditioning levels and conducted under medical supervision. Problems arise when intensity or environmental exposure exceeds individual capacity or when activities lack alignment with sport‑specific conditioning plans.

The case at ASU underscores why departments routinely require credentialing and written agreements for volunteer trainers. Those documents specify scope of work, supervision, emergency procedures and insurance coverage. They also ensure the team trainer and medical staff have real‑time authority to modify or stop activities and to remove athletes from drills if concerns arise.

Collegiate programs increasingly formalize policies around guest instructors to prevent situations where accountability is ambiguous.

Community reaction, support networks and the role of social media

Mayich’s collapse prompted an outpouring of support from former teams, teammates, and the hockey community. Daily prayer services attracted hundreds, and social posts from the Ottawa 67’s and friends used his nickname “Mayo” to rally messages of encouragement. These public displays reflect the close bonds within hockey communities and the broader impact of sudden injuries on small‑world athletic networks.

Social media can amplify support and also spread incomplete or speculative information. Athletic departments must balance the family’s request for privacy with the community’s desire to know what happened. Transparent and timely communication that respects medical privacy but provides factual updates can reduce rumor and misinformation.

Universities also have a role coordinating support services for athletes and teammates after traumatic events. Athletic departments commonly offer counseling, chaplaincy or spiritual care, and academic accommodations for teams affected by a serious medical incident.

Lessons for athletic programs: prevention, policy and culture

Several practical lessons emerge for college programs from the ASU incident, regardless of final findings:

• Formalize procedures for approving and supervising outside trainers. Written agreements should spell out authority, safety obligations and integration with medical staff.
• Reinforce EAPs and rehearse them publicly so coaches, trainers and athletes know their roles. Conduct post‑exercise debriefs to capture concerns early.
• Make AEDs visible and accessible at all outdoor venues, and ensure staff maintain current CPR/AED certifications.
• Embed environmental monitoring into practice planning, with objective thresholds that trigger modifications.
• Prioritize preparticipation screening and educate athletes about reporting symptoms. Normalize pulling athletes from activity for evaluation without stigma.
• Document coaching decisions, rest breaks, hydration schedules and supervision for every high‑risk session. Good documentation protects athletes and institutions.
• Cultivate a safety culture where medical staff have authority to stop or alter workouts without fear of repercussion.

Examples of institutions that have reformed practices after on‑field emergencies show these steps can materially improve outcomes. Schools that trained all sideline personnel in CPR and ensured AED availability reported faster defibrillation times and higher survival in sudden cardiac arrests.

What investigators will likely examine next

Investigators, whether from the university, athletic conference or independent reviewers, will collect evidence to reconstruct the sequence of events and identify contributors. Key items include:

• Sign‑in logs and authorization records for the workout.
• A timeline of presence/absence for coaches, trainers, volunteers, and the athlete.
• Environmental data (temperature, humidity, WBGT if available) for the time of the session.
• Medical records of the athlete’s preparticipation evaluations and any recent illnesses.
• Witness statements from coaching staff, teammates and volunteers.
• Surveillance or phone video that may capture the event and immediate response.
• Emergency medical services records and hospital documentation of prehospital interventions and in‑hospital care.

A transparent, methodical review serves both the family and the community by establishing facts and identifying improvements.

Historical and international context: sudden collapses in sport

Several high‑profile athlete collapses in recent years illustrate how rapid response saves lives and how ambiguity around causes can linger. The European Championship collapse of Danish midfielder Christian Eriksen in 2021 was due to cardiac arrest linked to myocarditis; immediate CPR and defibrillation on the field were credited with saving his life. In the United States, NFL player Damar Hamlin’s on‑field cardiac arrest in 2023 highlighted how prompt resuscitation and coordinated emergency response can produce recovery.

Universities that have experienced tragedies have sometimes revised policies and invested in medical staff and emergency equipment. Internationally, countries such as Italy have implemented wide ECG screening programs for young athletes, aiming to identify certain cardiac conditions before they become catastrophic. Those programs carry costs and false positive rates that make them controversial in some settings, but they illustrate the range of policy responses institutions consider.

Transparency, family privacy and public expectations

Balancing transparency with respect for the athlete’s medical privacy presents a dilemma for institutions. Families often request confidentiality in the immediate aftermath, while teammates, alumni and the public expect updates. Clear, compassionate statements that confirm facts without disclosing sensitive medical details can help manage expectations. Over time, families may authorize more information or the institution may release findings following review.

ASU’s promise of a “thorough review” aligns with institutional needs to document what occurred and to propose corrective steps if warranted. The university’s final report, if released publicly, could include recommendations for policy changes, staff training, or equipment upgrades.

Recommendations for athletes, coaches and campus health leaders

For athletic programs and campus health leaders seeking to reduce the risk of similar incidents, the following actions are practical and evidence‑based:

• Require documented medical clearance and symptom screening before preseason training.
• Implement an objective acclimatization protocol for new and returning athletes to reduce heat‑illness risk.
• Ensure athletic trainers or licensed medical personnel are present at all team conditioning sessions, including those involving outside trainers.
• Mandate written authorization and integration plans for guest instructors; prohibit unsupervised volunteer‑led physical conditioning.
• Maintain and regularly audit AED availability at all practice and competition sites; conduct frequent drills for EAP activation.
• Train coaching staff to recognize early signs of heat illness, cardiac distress and neurologic impairment, and to defer to medical staff decisions.
• Provide education for athletes about reporting symptoms, hydration strategies, and pacing during high‑intensity drills.
• Conduct post‑incident reviews that include psychological support for teammates and staff.

These steps require institutional commitment and resources but represent standard practice at many leading programs.

Community and cultural implications

This episode intersects with broader cultural questions about toughness, rites of passage and the role of outsider figures in building team character. Military‑style training carries symbolic weight and can foster resilience; yet conditioning must be informed by sport science and medical prudence. Athletic departments should be mindful that cultural traditions do not override medical judgment and safety standards.

The shift toward athlete welfare as a primary institutional priority has accelerated in recent years, with increased scrutiny from media, families and athletic oversight bodies. Incidents like the ASU collapse test how institutions apply those commitments in practice.

Where the story stands now

As of the latest reporting, ASU is conducting a review of the Aug. 20 workout that preceded sophomore defenseman Matthew Mayich’s collapse. The ex‑Green Beret who led part of the session, Tim Ziesel, says he left before the incident and that coaches and medical staff were present during the drills he supervised. Mayich remains hospitalized and in critical condition; his family has asked for privacy while the community continues to offer support and prayers.

The university review will determine whether procedures were followed, whether oversight was adequate, and whether changes are required to prevent recurrence. That process will shape institutional practices and inform public understanding of how collegiate athletic programs manage outside trainers, environmental risk and emergency preparedness.

FAQ

Q: Who led the workout where the ASU hockey player collapsed? A: Tim Ziesel, a former U.S. Army Green Beret, led a portion of the outdoor conditioning session. He says he completed his portion of the workout and left before the player collapsed.

Q: What happened to the athlete? A: Reports indicate that sophomore defenseman Matthew Mayich suffered an apparent cardiac event during the workout, was taken to a hospital and later transferred to Barrow Neurological Institute, where he remained in a coma as of the last public update.

Q: Did ASU have medical staff on site? A: According to statements by Ziesel’s attorney, head and assistant coaches and medical staff were present. ASU has confirmed that medical personnel responded to the incident but has not publicly detailed on‑site staffing or interventions.

Q: Was heat a factor? A: Emergency responders were dispatched for a heat‑related illness call, and ambient temperatures at the time were reported between 87 and 89 degrees. Whether heat directly caused or contributed to the collapse has not been publicly confirmed.

Q: Is the university investigating? A: Yes. ASU has stated it is conducting a review of the circumstances surrounding the workout and the athlete’s collapse.

Q: What will investigators look for? A: Reviewers typically examine authorization for the workout, supervision, presence of medical staff, emergency response actions, timing and sequence of events, environmental conditions, the athlete’s medical history, and adherence to written policies and guidelines.

Q: Can outside trainers lead official team workouts? A: Policies vary by institution. Best practices call for written authorization, integration with medical staff, and clear supervision by credentialed athletic personnel when outside trainers work with student‑athletes.

Q: What immediate actions improve survival in on‑field cardiac arrest? A: Rapid recognition, immediate high‑quality CPR, prompt AED use, and quick activation of advanced life support all increase the chance of survival. For exertional heat stroke, rapid whole‑body cooling is essential.

Q: What should athletic programs do to prevent similar incidents? A: Establish and enforce preparticipation screening, acclimatization protocols, environmental monitoring, EAPs, on‑site medical coverage, AED availability, and formal rules governing outside trainers. Regular drills and documentation are critical.

Q: How can teammates and the community support the player and family? A: Respect family privacy while offering practical support such as meals, fundraising where appropriate, messages of encouragement, and attendance at permitted memorials or prayer services. Athletic departments should provide counseling and support services for teammates.