Hagler used to isolate himself at the very tip of Cape Cod (near his hometown Brockton, Massachusetts) in a remote beach hotel. He would wake up at 3 AM every morning and do sprints of up to 6-8 miles on the beach at Cape Cod in heavy combat boots- half of it running backwards. Sprints are a great way to build up your endurance and body. Sprinters maximally contract their muscles, which requires a lot more work than a slow, staggered, constant run. Not to mention, your testosterone and hormones are released in greater amounts with short maximal energy bursts. During the winter, it was said to be one of the coldest places on Earth due to the heavy wind. Marvin would actually be screaming due to the pain of the cold and the pain in his legs and lungs. Then he went into "solitary" till six in the evening. At six, he went to the gym they'd set up alongside the pool at a hotel nearby. Your body tends to burn even more calories in the cold, as your energy expenditure increases. Therefore, this could be part of the reason why Hagler was extremely lean. There, they would perform a circuit of jumping rope, heavybag, speedbag, and situps (where they'd do several rounds each), but one strict rule was adhered to: three minutes work, one minute rest, for all of it. This mimics that of a typical boxing match and will get Hagler ready for his matches. After that they would do their sparring routine. Marvin had to have several sparring partners in camp with him because he used them up with such regularity. "Marvin don't ease up on you," said longtime sparring partner and world champion Buster Drayton. There's no play when it comes to Marvelous Marvin; "he comes to work". This is another great way to get him ready for his matches. Marvin would spar with three to four sparring partners, where he went two rounds each before moving on to the next fresh partner. This dramatically improved his conditioning and taught him to remain in great position even while he was tired. Drayton also said that his sparring partners would leave the ring with the insides of their mouths so chewed up from Hagler's blows that they couldn't even eat dinner that night. After that, he would rest, eat, and watch film of himself and his opponents. The workouts were open to the public, so he'd remove his gear, toss a nod to the audience, and return to the self-imposed solitary confinement. Those working with him in camp have said that he wouldn't even socialize, because he wanted to remain so focused on his goals. He stayed in his room, and could be seen frequently sitting alone on his balcony staring out at the Cape water for long periods at a time. Marvin made sure that he worked out 7 days a week and got atleast 100 rounds of sparring in every week, but most importantly, he was always fast asleep by 8 PM to get his 7 hours before his 3 AM run.