This is been my suspicion all along. I would almost be willing to bet that an outside agent was at work here: for example, possible environmental contamination, excessive use of aspirin to deal with the pain, contaminated or unauthorized supplements. The doctors who have been put in charge of this investigation will need to look beyond the workout regimen.
Did other factors affect stricken Hawkeyes? | Hawk Central
I posted an article about a case of rhabdomyolysis in 7 DI swimmers that occurred last year (I think).
First,
rhabdomyolysis can occur with absolutely nothing other than strenuous exercise. In the case of the swimmers, they maintained that they were well hydrated, and denied drug/alcohol use or the use of dietary supplements. It's not always likely in young, fit athletes, but it
can happen.
However, there are other factors that can cause rhabdomyolysis including
Hyponatremia: Low sodium levels. There are two possibly relevant cases here. Hypovolemic hyponatremia is when your water and sodium levels are low, which would be due to water and electrolyte loss during exercise. The second is exertional hyponatremia, where you lose sodium through sweat, but actually take in too much water during exercise, and dilute whatever sodium you have in your body.
Hypokalemia: Low potassium levels. This can be caused by dehydration, vomiting, or the use of diuretic pills (water pills). I suppose overhydration can also lead to this. Any of us who've worked out a lot before know that vomiting isn't uncommon.
Note: Both can be caused by the use of 'water pills' or other diuretics, which people do use for weight loss.
Influenza A or B, other viral or bacterial infection: The flu can affect your muscles. There have been cases of exertional and non-exertional rhabdomyolysis in patients with influenza A, as well as H1N1. If you've had the flu, you know the muscle fatigue that can go along with it. Overworking muscles in this state could lead to rhabdomyolysis, I suppose.
Note: The usage of certain medications to treat these could, I suppose, also aggravate muscle damage.
Extremes in body temp: hypothermia or hyperthermia, the latter of which can be caused by a fever or simply working in a hot environment.
Drug/alcohol use: Since the tests came back negative for illegal substances, this is unlikely.
Supplements such as creatine or diuretics used for weight loss:
Environmental conditions (besides heat): Air quality could, I guess, affect your muscles.
As the OP mentioned, excessive aspirin use can also lead to this condition, as can the use of antihistamines and caffeine. I'm not sure about ibuprofen or acetaminophen use.
TL;DR: Basically, this could be nothing but the result of strenuous exercise. However, it could have been helped along with any number of other factors, from lack of rest, to alcohol use, to supplements, to viral infection, or some else.