Edwards pointed out that Beach Body programs contain explicit statements warning exercisers to check with their doctors and not overdo it. They are encouraged to take the fitness test that comes with their program that can help them evaluate whether or not they are ready. If they're not, they can ask for a refund, he said.
He added that Beach Body instructors demonstrate several different versions of the exercises within the workouts to accommodate the less fit and those struggling with problems like bum knees and sore backs.
Experts said problems can arise when exercisers try to do too much, too soon.
Dr. Stephen Fealy, an orthopedic surgeon with the Hospital for Special Surgery in New York, said he started seeing a spike in HIITs-related injuries two years ago. Now, at least one patient a week who has overdone it limps into his office.
Rather than traumatic injuries like broken bones and stress fractures, he said, high-intensity exercisers tend to rack up muscle sprains and tendon strains, particularly of the calf, chest and shoulder, the result of overusing explosive movements and heavy weights.
"I think these programs are quite good, but if someone goes from couch to full throttle without any preparation, there's a good chance they're going to get hurt," he said.
As for reports of cases like Lombardi's rhabdomyolysis or other serious medical consequences, Cedric Bryant, the chief science officer for the American Council on Exercise in San Diego, noted that they have been few and far between.
"Most people naturally back off before they get to that point because they don't have the capacity to push themselves that far," he said. "Because most people starting out are less than fit, they may perceive they are really going for it but, physiologically, they have to stop long before they can get into this kind of trouble."
Bryant said anyone can do some kind of damage to their body if they jump into any sort of fitness routine without proper training, but people like Lombardi -- who claimed to be in decent shape before he tried the workout -- are at greater risk for doing serious harm because they can physically perform at a level that someone who is out of shape and overweight can't.
Richard Joe, who owns a Cross Fit gym on the Upper East Side of New York City, said the goal of Cross Fit is to be able to complete the workouts, which can be super intense, but not from day one.
"The best way to do Cross Fit is to work with an experienced coach who can help you set reasonable goals for you to gradually work towards," he said.
Bryant said he is a fan of high-intensity workouts because they can be time- and budget-conscious -- and because they often get results where other workouts may not. He did, however, stress how important it is for newbies to "listen to their body" and work their way into a HIITs program by doing some moderately paced exercise for a month or two.
"You must be smart enough to respect your physical boundaries," he said.
Lombardi, who said he's done with heavy lifting programs, agreed.
"I don't blame the workout -- but I do want people to know this can happen," he said.
Have you tried a HIITs style program? What was your experience? Feel free to sound off in the comments section below.