Marathon Challenge

PBS Airdate: October 30, 2007

NARRATOR: The Boston Marathon, the most famous road race in America: for some, the ultimate test of endurance. There's pain, suffering and success.

But where does that ability to endure come from? What's the physiological difference between those that can run over 26 miles and those that can only watch in awe?

Can an average person, standing on the sidelines, be transformed into an athlete crossing the finish line?

NOVA intends to find out.

XENIA (Team NOVA/Child Psychiatrist) : Well, I'm not engaged in any physical activity, currently.

MIC (Team NOVA/Physical Therapist) : Basically, walking.

SAMA (Team NOVA/Hotel Sales) : Like, the maximum I do is bowling.

MELISSA (Team NOVA/Fundraiser) : So we're talking 26 times what I've ever been able to accomplish.

LARRY (Team NOVA/Psychotherapist) : I had a heart attack 12 years ago.

CAROL (Team NOVA/School Administrator) : I have the motivation, I have the energy—don't quite know how I can do it, still, kind of, physically.

DANIEL (Team NOVA/Academic Advisor) : That somebody with HIV can actually go out and train and run in a marathon...

NARRATOR: Chosen from hundreds of applicants, these are the participants in a real-life experiment.

JONATHAN (Team NOVA/Entrepreneur) : I do feel like I am on some new, latter day, public television version of Survivor .

NARRATOR: They come from all walks of life but share a common dream to run the Boston Marathon. Can they do it? Could you?

Marathon Challenge , right now on NOVA.

NARRATOR: The track at Tufts University, near Boston, in the heart of summer: it's Team NOVA's first day together, with 40 weeks of training ahead, all in preparation for the next Boston Marathon.

MELISSA: Really, when someone says to me, "Don't worry. Do what you're told. We'll train you to run the marathon," it really feels to me like somebody is saying, "Come on over tonight. I'll teach you Japanese, and you'll be fluent by tomorrow." It feels that truly impossible.

CAROL: I don't know what I'm doing. I can't run half a mile. I can't even run half a block!

JANE (Team NOVA/Teacher) : You know this is big, but you don't realize how big it is, and the more you get into it, it's like, aahh!

XENIA: It feels like just stepping on the track means that there's no turning back at this point.

NARRATOR: NOVA wants to know if, in nine months, a group of sedentary non-athletes can be transformed into marathoners. But we don't expect them to do it alone. Miriam Nelson, a Tufts professor, exercise physiologist, and a marathoner herself will help out.

MIRIAM NELSON (Tufts University) : It seems to me that they have a long way to go, but that they are sort of primed and ready.

NARRATOR: The day-to-day responsibility will rest on Don Megerle, a Tufts coach.

DON MEGERLE (Tufts University) : I said to them up there, "Your bad days are my bad days, you know? Your problems are my problems. You don't know that now, but you'll get to know that."

When you watch them move around as a group, they're not...it's not an athletic group. No one came in as, you know, buff, ready-to-go runners, no one like that. They're pretty much dog meat, you know? I can't say that.

NARRATOR: Also helping with the transformation is Uta Pippig, a three-time Boston Marathon winner. For her, running isn't just a sport, but a way of life.

UTA PIPPIG (Take the Magic Step, LLC) : What I believe is their biggest challenge, to be able to have fun, be excited, keep the excitement that they do something very special for their body and for others who see that. They have the spirit already. I could see this, the desire, "I want to do this."

NARRATOR: They've come for different reasons. Some are battling time.

MIC: I'm 37. I want to prove that I can still run a marathon.

RAY (Team NOVA/Computer Technician) : It wasn't an easy thing to realize that you're 50.

JANE: And I'm glad you're going to let me show the world that 60 ain't so old.

NARRATOR: Others are trying to overcome health problems.

LARRY: I had an unexpected heart attack when I was 43.

DANIEL: I've been HIV-positive for 13 years.

VERA (Team NOVA/Student) : I lost about, like 85 pounds, so...

NARRATOR: While Vera just lost weight, Betsey has gained.

BETSEY (Team NOVA/Hospital Administrator) : I'm overweight more than I'm under-fit.

NARRATOR: She's hoping that marathon training will help her lose the 70 pounds she put on while recovering from surgery.

BETSEY: So this, for me, felt like it was a way to really take control of my life again, and in a group process. So this really felt like it was the only way I was going to be able to do it.

NARRATOR: Some members are seeking a way through tumultuous times. Sama is grieving over the death of her mother in a hit and run accident.

SAMA: Well, I am having a very difficult time, still, dealing with my mother's loss. I just, like, don't show it all the time, but when I talk about it I don't feel well.

NARRATOR: And some of the team, like Jonathan, just feel out of shape, despite being constantly on the go.

JONATHAN: I am on the go a lot—in seats: in car seats, airplane seats, conference room tables, restaurant seats. My job largely involves seats.

NARRATOR: To make sure the runners get off their seats safely, NOVA collects some baseline health information.

First up is the DEXA, a scanner that uses low-level radiation to determine body composition, a ratio of lean to fat. Some fat is healthy, and your body needs it, just not too much.

For 40-year-olds, body composition of about 20 percent for men and about 24 percent for women is considered good.

Betsey's result is over 45 percent. She's nearly half fat.

But even people who don't look overweight can be over-fat.

MIRIAM NELSON: What we see often now is somebody that is ideal body weight but overly fat. And this happens all the time because they're simply sedentary and they haven't used their muscles, so they've accumulated body fat. They actually, with an ideal body weight, can be overly fat and under-muscled.

NARRATOR: As it turns out, almost all the women on the team are technically obese.

One is 28-year-old Sama. She doesn't appear to be particularly heavy, but her body composition came in close to Betsey's, suggesting a very sedentary life.

SAMA: The maximum I do is bowling, and so I consider that physical.

NARRATOR: If bowling really is Sama's only exercise, the next test will show the consequences.

ROGER FIELDING (Tufts University) : Okay, just lift your shirt up for me right there.

NARRATOR: As Sama runs on a treadmill, her exhaled breath is captured by a mouthpiece and then analyzed for oxygen content, revealing how much oxygen she's using.

MEDICAL TECHNICIAN: In about 30 seconds, I'm going to increase that incline and the speed, okay?

NARRATOR: The goal is to find the maximum rate that Sama's body can consume oxygen, her "VO 2 max."

ROGER FIELDING: VO 2 max is really the measure of the person's body's ability to extract and utilize oxygen during exercise. And it's the best measure we have of a person's cardiovascular or aerobic fitness.

NARRATOR: Here's why: to run, your leg muscles must continually contract and relax. The source of the movement lies deep inside each muscle cell where tiny proteins grab and release each other. But each grab and release requires energy. This energy comes mainly from fat and carbohydrate, mixed with oxygen.

ROGER FIELDING: Basically, the muscles break down fat and carbohydrate to make energy, and in that process, we burn and consume oxygen.

NARRATOR: So, to keep running, Sama's body must move large amounts of oxygenated blood from her lungs all the way to those tiny filaments inside each muscle cell.

MIRIAM NELSON: When we measure somebody's VO 2 max, it's a very interesting number, because it is really complicated and there are a lot of different factors.

So it's how well the heart is beating; it's how well the vessels are expanding, how elastic they are; how many capillaries there are to bring the oxygenated blood to the muscles. So it's one number that shows us an overall good health of the entire cardiovascular system.

ROGER FIELDING: Stop. Slow it down. Stop right here.

NARRATOR: Sama's VO 2 max is better than one would expect from her DEXA. She's at the low end of "fair."

ROGER FIELDING: So, as you become more fit and do more training, we would expect this, the VO 2 max value, to go up, increase.

NARRATOR: That puts her in the middle for Team NOVA.

MIRIAM NELSON: I'm really amazed at how low some of the VO 2 maxes were.

JANE: It's hard to breathe with that on.

ROGER FIELDING: It is, yeah. It's a little dry.

MIRIAM NELSON: The fitness level was almost at, sort of, a cardiac rehab level.

ROGER FIELDING: Your fitness level is a little bit less than we would expect from someone in your age range.

NARRATOR: Elite distance runners achieve double or even triple the scores of Team NOVA, even when they stop training, suggesting some innate ability.

But Team NOVA finds some of that as well.

Fifteen years ago, Jonathan ran, in college. But now he just plays the occasional game of tennis and jogs a bit, which doesn't explain this.

ROGER FIELDING: He reached Stage 6, which is a very high fitness level. We see very few people that get up to this Stage 6 level.

NARRATOR: He has the highest VO 2 max of the group by far: about the level this lab sees when it tests professional hockey players and endurance athletes.

ROGER FIELDING: It's clear that there's a strong genetic component embedded in what a person's baseline aerobic capacity is, and some people start at a higher baseline than other people. I think that's part of what we're seeing.

MEDICAL TECHNICIAN: That's it. We're just going to cool you down now.

JONATHAN: That's why they call it the O 2 max.

MEDICAL TECHNICIAN: You got it.

NARRATOR: While Jonathan seems to have won the genetic lottery when it comes to athletic potential, other members of Team NOVA aren't so lucky.

Betsey has fought hard to be included on the team, though NOVA's been advised that she should lose her extra 70 pounds before attempting any marathon training.

MEDICAL TECHNICIAN: Nice work, that's good. Good job.

NARRATOR: But Betsey is determined.

Then there's a rare event. Almost before it starts, the doctors call a sudden end to the test.

MEDICAL TECHNICIAN: Stop the test. Okay, we're going to stop. We're going to stop it now.

NARRATOR: The monitor has picked up some irregular heartbeats, a possible sign of heart disease or even an oncoming heart attack.

ROGER FIELDING: So we stopped the test because you had a couple of extra beats that started happening in your heart during the test. And it was enough that we wouldn't want to proceed with the test, so that's why we stopped.

NARRATOR: It's a red flag that could disqualify Betsey from Team NOVA.

ROGER FIELDING: One-seventy over 86.

NARRATOR: For her, that would be devastating.

Betsey has been struggling to get her life back on track, after the breakup of her marriage and undergoing a major surgery, removing a tumor near her spine.

BETSEY: Two years ago, my life came crashing down. So for me, I really see this as an opportunity to kind of triumph over that. I fought this hard to get here, and I just want to see it through. We'll see. It's never over 'til it's over, I guess.

NARRATOR: Betsey must undergo further testing to see if it's safe for her to train, while the rest of Team NOVA hits the road.

Training these would-be marathoners will rely on a carefully laid out schedule: short runs on their own during the week, with a big group run each weekend, of increasing length.

Months from now, the final training run will be 20 miles. The starting point today is just two. For people who rarely exercise, it's a long way. And for Sama, it feels especially long.

SAMA: It was very difficult, and it was very challenging, and I felt very unfit. Well, I knew that, but I didn't realize how unfit I am.

DON MEGERLE: She said, "I've been cheating." And I said, "On what?" She said, "On myself." I said, "What have you been doing?" She said, "I'm smoking again." I said, "Sama..."

You can't continue the training she's going to do and smoke. You can't.

MIRIAM NELSON: A chronic smoker is going to have diminished lung capacity. And lungs are obviously really important, because your respiration goes up with exercise. So, one of the first things that anybody needs to do is to stop smoking, to be as healthy as possible.

NARRATOR: Sama promises Don this time, she's really quitting.

In the third week of training, Team NOVA is rejoined by Betsey.

BETSEY: Morning!

NARRATOR: She's received the "all clear" from her cardiologist, though her weight keeps her at the back of the pack.

BETSEY: Everybody has to start somewhere, but I feel like I'm not too far behind.

NARRATOR: Team NOVA has 12 members now, but the coaches expect as many as half will drop out.

MIRIAM NELSON: When you are looking at taking people that are totally sedentary for the most part, some of whom are actually overweight, a number of whom also have a number of health issues that are going on, maybe a third, maybe even a half might not make it, mostly because of injuries.

NARRATOR: Already some team members are in doubt.

Melissa is suffering from shin pain, sometimes called shin splints. Sometimes the pain is caused by mild irritation to the shin bones, but in Melissa's case, it's more serious.

MELISSA: Remember I was complaining about shin splints last week? I have a stress fracture. No running for about six weeks.

TEAM NOVA MEMBERS: Wow!

MELISSA: I know. So I'm a little panicked about getting left behind.

NARRATOR: Bones usually break from a single blow. But a stress fracture comes from repeated minor trauma, the kind of high-impact pounding that happens in running.

It's an injury found in animals that race: horses, greyhounds and humans.

MELISSA: I never fell; I've never been a runner, so I don't know where the stress fracture came from, except...

NARRATOR: Complicating Melissa's situation is her Type I diabetes, which may double the time it takes to heal.

MELISSA: While my large blood vessels are fine, it's the microscopic blood vessels that are feeding the bones down there, and that's were the damage first occurs when you are diabetic, so it just takes longer.

NARRATOR: Melissa's not the only one with problems. Xenia, a doctor herself, was nervous from the start about getting hurt.

XENIA: I'm afraid of injury. I'm afraid that my knees might go. That's probably my biggest fear.

NARRATOR: Now Xenia's knees aren't going, but like Melissa, she's got severe shin pain, though a bone scan shows a different result.

XENIA: Well, he actually said there wasn't a stress fracture, he didn't see one.

DON MEGERLE: So no stress fracture?

XENIA: Yeah.

DON MEGERLE: Very good, very positive.

XENIA: That's good! I'm very excited about that.

NARRATOR: With no clear diagnosis, Xenia is prescribed rest and some intensive physical therapy.

But the issues facing Team NOVA aren't all physical. For the first two months, as the team runs together on weekends, one member is completely M.I.A.

DON MEGERLE: Hi, Jonathan, we just finished our third team training run this morning. It was pretty hot for the runners but they're doing quite well.

Hey, Jonathan, Don Megerle calling. We hope to have you with us next week.

We just had a run out here on the Mystic Lakes with the NOVA team. So I know you plan on being with us next Sunday. We'll see you then, Jonathan.

NARRATOR: Finally, after 9 weeks, Jonathan makes it to a group run.

MELISSA: Welcome back. We missed you!

JONATHAN: Thank you.

NARRATOR: The CEO of a fast-growing company, Jonathan is a father of five, in the middle of a messy divorce.

JONATHAN: I suppose that's the profile that I represent in this, to a certain degree, is people who just can't do it, just can't pull themselves together, because they've got too much going on. And I definitely am in that category.

NARRATOR: Jonathan's reappearance coincides with a big day for Team NOVA, the longest run to date, five miles.

On hand is marathon royalty, three-time Boston champ, Uta Pippig.

DON MEGERLE: We have Uta with us today.

UTA PIPPIG: Five miles, it's the longest run for most of you today. You can do it, but start a little bit slower if you want.

NARRATOR: For this run, Melissa's still on the sidelines, but Xenia has been given the okay to try a shorter distance.

XENIA: I don't know why I'm so afraid. One, I think I just don't want the pain to come back, but, two, I'm like, can I really do three miles at this point?

DON MEGERLE: Xenia, no pain running three miles? That was, that was huge. So I'm excited about that.

NARRATOR: Once again Jonathan surprises, easily finishing the five miles.

For some, like Carol, it's a struggle.

CAROL: I just remember at one mile, it was hard. And thinking that...five miles? I just didn't know I could make it.

NARRATOR: But she did make it. And so did everybody else.

UTA PIPPIG: Today, unbelievable. I was so surprised about their improvement.

NARRATOR: So in nine short weeks, what's happened? What's changed?

The runners' hearts are more efficient, filling up faster between beats and pumping more blood with less energy. They might even be slightly bigger.

MIRIAM NELSON: Certainly the heart is working a bit better. But by far, the majority of the changes are happening with the vessels, the plumbing of the body.

NARRATOR: Arteries and veins have become more elastic, easing blood flow. And down at the level of the muscle cell itself, there are more tiny capillaries, meaning faster delivery of oxygen.

Even inside the cell, energy production has been ramped up by mitochondria, the structures that transform fat, carbohydrate and oxygen into energy.

ROGER FIELDING: As you become more and more trained, the muscle actually starts making more mitochondria and also making them larger so that they can actually process and break down more fuels for energy.

NARRATOR: So in nine weeks, from their hearts to the tiniest enzymes in their cells, these bodies were transformed.

MIRIAM NELSON: The human body is an amazing organism. And what we see is that when you don't use things, you lose that body tissue.

The first day that you go out and exercise, you are healthier than the day before, because the body all of a sudden realizes, "I've got to use those muscles. I have to make them stronger. I have to make them fitter. I have to make them so that I can cover more ground." So it's a survival mechanism that our body is responsive to the demands that we put upon it.

NARRATOR: But for some body parts, the demand can prove too much. It's estimated that every mile run puts over 110 tons of force on our bones and joints.

As the team moves into longer and longer runs, the injuries start to mount.

MIC: It hurts.

NARRATOR: Carol is soon hobbled by hip and knee problems.

CAROL: Is it like joint? Is it muscles? Is it ...? I don't know. I have no idea. This feels like it's going to like pop out of...like, not go forward, so...

NARRATOR: Melissa has been on the sidelines for months as a result of her stress fracture.

MELISSA: It's about time!

NARRATOR: She's finally been cleared to see if her shins are better by attempting a short run. At first, things look good.

MELISSA: To do a mile run, no pain, so far, in my legs, gives me hope.

NARRATOR: But a second short run leads to more shin pain.

MELISSA: That's bad.

NARRATOR: When a bone scan the next week reveals multiple stress fractures in both her legs, Melissa is officially out.

MELISSA: I wasn't not able to do it because I just couldn't get myself up in the morning to do the runs, or it was too cold to go outside. It's 'cause I broke. And that just...I never expected that that would be the reason I couldn't run the marathon.

NARRATOR: Team NOVA's lost one member, but has a new recruit to take the spot. Steve DeOssie is an ex-NFL lineman, most recently for the New England Patriots. He now works as a sports commentator on television and radio.

RADIO DJ: They're second in the league in points allowed, period, end of story.

STEVE DEOSSIE (Team NOVA/Sports Commentator) : Hold on, hold on, I'm with you on this argument.

I am designed and built specifically to run five yards and hit something with a lot of violence.

NARRATOR: At nearly 300 pounds, he's an unlikely marathoner, but that makes him perfect for Team NOVA.

STEVE DEOSSIE: Coach...

DON MEGERLE: Good morning, Steve. I want you to meet some of your new teammates. I want you to meet Steve DeOssie.

STEVE DEOSSIE: How are you?

Why am I doing this? When I thought about it, I realized it was so ridiculous, that it was actually intriguing. It's sort of a situational comedy.

NARRATOR: As a pro athlete, Steve went to the Superbowl. But as a marathoner, he won't be setting any records. He's ill-suited to the task, right down to his muscles.

STEVE DEOSSIE: I didn't sweat like that since the SATs, unbelievable.

NARRATOR: Everyone is born with a mix of two different types of muscle fiber. One contracts faster and with more force in short bursts of activity. It's found in greater proportion in the muscles of sprinters, and weightlifters, power athletes like Steve.

The other fiber type has less power but more endurance. Biopsies have shown it can make up almost 90 percent of the skeletal muscle of an elite marathoner like Uta Pippig.

Steve may not have the right muscle type, but Uta still sees promise.

UTA PIPPIG: He does a good job, guys. He really does a good job. Shoulders down, can you see? Arms easy, he has a relaxed step.

STEVE DEOSSIE: Thank you, sir.

DON MEGERLE: He's doing all right, DeOssie. He really is.

NARRATOR: Steve's embrace of endurance running raises the question, are we all born to run?

Some human features seem just right for the job like the springy arch of the human foot. Hairless skin and abundant sweat glands provide exceptional cooling. We also have large muscular butts which prevent us from tipping too far forward.

Humans don't run fast. Sometimes even squirrels can outrace us. But in a warm climate, over distance, we can outrun dogs, antelope, and even horses, which will all overheat.

In our evolutionary past, that may have been a killer advantage.

DANIEL E. LIEBERMAN (Harvard University) : Early humans were so good at running in the middle of the day that they were able to run animals to exhaustion and to heat stroke. And then, at that point, the animal's already dying. It takes no technology to kill that animal, so you can safely and effectively, and fairly easily, have access to meat.

NARRATOR: We may be built for running and hunting in the heat of the savannah, but that's a long way from Boston in winter.

In early December, after five months of training, Team NOVA is faced with its first 10-mile run. They're joined by the Tufts Marathon Challenge, a charity group led by University President Larry Bacow.

Ten miles is farther than most anyone on Team NOVA has ever run. For one person, it lands on the anniversary of a life-changing event. This week, 14 years earlier, Daniel thought he just had a bad flu.

DANIEL: I pretty much figure that's when I became HIV-positive, so I pretty much consider that my benchmark, that first week in December, 14 years ago. And here I am running 10 miles, pretty awesome.

NARRATOR: Not everyone makes it through the run smoothly.

SAMA: My knee hurts, and I don't think I'm over my cold yet.

NARRATOR: Sama's knee is in trouble. In fact she won't run again for months.

As Boston grows colder, winter means bad memories for Larry. Fourteen years earlier, he suffered a heart attack while shoveling snow. Larry was relieved when his cardiologist okayed his training.

LARRY: ...especially finding out that I can run in cold weather, which was a scary spot for us, 'cause it was in cold weather that I had the heart attack.

NARRATOR: But fears are understandable. On rare occasions, people have had heart attacks and even died during marathons.

MALISSA WOOD (Massachusetts General Hospital) : The risk for dying during exercise is one out of 50,000. So it's higher than the risk of dying when you're just standing around in a sedentary fashion.

NARRATOR: Malissa Wood is a cardiologist who studies the effects of marathoning on the heart. And she's found how well the heart fares during the race depends on how diligently the runner has trained.

MALISSA WOOD: If the individual has not trained their heart adequately, the heart really starts getting tired. In people that have trained adequately for the marathon, their hearts look fine.

NARRATOR: Most heart attacks aren't caused by just tired and stressed heart muscle, but by blocked coronary arteries, often associated with poor diet and lack of exercise.

MALISSA WOOD: People that are sedentary are more likely to have these blockages in their arteries. And with adopting a healthy lifestyle, exercising, we think that those blockages actually decrease in size, or become much less prone to rupture. So people who do exercise regularly are much less likely to experience sudden death during exercise.

NARRATOR: Having been given the all clear by his doctor, it turns out that running is one of the best things Larry can do for his heart, even when it's cold outside.

Winter's been less kind to Sama, who's been nursing an injured knee.

SAMA: I didn't run from the first week of December to the second or third week of February. I missed all the runs. I have to tell you that every single run is actually hard for me. I have to push myself.

NARRATOR: Now, she's just returned from the week-long trial of the man accused of killing her mother in a hit and run accident in Kentucky.

SAMA: My mom died suddenly and tragically, so there was too many months with, like, you know, between shock and anger and denial, and I think now it's, like, time to start missing her.

NARRATOR: Sama chose to train for the marathon as a tribute to her mother. But with her weak physique and joint problems, there are growing doubts about whether she'll make it to the starting line.

The team's first run was two miles. By the fall they were at five; December, 10; and now, in late winter/early spring, the team has moved up to 12 to 16 miles on the weekend, many on the Boston Marathon course itself.

Runs of this length aren't about improving aerobic fitness. Those benefits were largely achieved through the earlier training.

MIRIAM NELSON: When we look at the gains from July to December, when they ran the 10-mile run, I believe that probably 90 percent of the fitness gains, in terms of VO 2 max, changes such as that, happened in that time period for most of the NOVA team.

Then what you have is changes in the soft tissue, so the ligaments, tendons and muscles sort of getting tougher, so it can withstand the time that you're, literally, on your feet pounding the pavement.

NARRATOR: Even Jonathan, able to coast through the early runs, has found some new respect for the distance.

So you ran in new shoes today?

JONATHAN: I did. Bad idea. Ow! What the hell? This is a lesson—from Mother Marathon—in respect, and I hear her.

MIRIAM NELSON: But I think an even bigger component is the sort of mental toughness that you gain from those long training runs. That really is important for the race day.

NARRATOR: Mental toughness is a must for runners to endure the physical beating the marathon provides.

But if the goal is good health, is all this suffering really necessary?

MIRIAM NELSON: Do you have to run a marathon to be healthy? And...the reality is that you don't. For many people, that goal is important to get them kick-started. But for most of the population, getting out and exercising three to six times a week is what we need. So many people can get fit and healthy by not necessarily running a marathon.

NARRATOR: None of the NOVA runners are marathoners yet, but they're already much fitter.

On a second round of tests, their VO 2 max scores go up dramatically, with most rated "excellent" or "superior."

Studies show, if they can maintain these levels, it could have a profound effect on the runners' long-term health and lifespan.

ROGER FIELDING: So, it turns out that the people who have higher VO 2 max values actually have a much lower risk of developing things like cardiovascular disease, high blood pressure, high cholesterol...and even their risk of developing Type II diabetes is reduced. So, the higher your VO 2 max, the overall better your health will be.

NARRATOR: Though all the runners seem to be healthier, that doesn't necessarily mean they're skinnier.

The new DEXAs show little change in weight or percentage of body fat. All of the women are still overweight, and most have not shed any pounds.

One big exception is Betsey.

BOOT CAMP INSTRUCTOR: We're going to do jumping jacks, so circle up.

NARRATOR: When Betsey joined the team she was 70 pounds overweight. With diet and a boot camp exercise program on top of her marathon training, she's lost 45 pounds and become the fastest female runner on the team.

With all that, it seems like the pounds should just melt away. But they don't.

BETSEY: I really thought it would just kind of come together very easily. And it's work. Every week, it's work.

NARRATOR: Part of the problem is that running doesn't consume as many calories as one might hope, not even the 26.2 miles of the actual marathon.

MIRIAM NELSON: People might be surprised at how little energy you need to expend to actually run a marathon. For my size runner, around 115 pounds, it's only about maybe 2,600 calories to 3,000 calories—only about twice as much energy as I need in the day to just maintain my body weight.

NARRATOR: When it comes to losing weight, diet trumps exercise.

MIRIAM NELSON: Diet may even be more important than the exercise for the active weight loss component. But for weight maintenance and for the prevention of weight gain, physical activity—and a fairly high volume of physical activity—is absolutely crucial.

NARRATOR: But runners still have to eat, especially since muscle cells can't get enough energy from body fat alone. They need a fresh supply of carbs, too.

This becomes clear three weeks before the marathon, in the longest training run: 20 miles. It turns out, for Larry, that's two miles too many.

LARRY: It started about mile 18, when I just sort of ran out of gas. Then I had all these people, these upbeat people around me, telling me to keep going. You know, Uta's chirping along next to me, "You can do it! You can do it!"

NARRATOR: Was that a good thing or a bad thing?

LARRY: Well, it helped. It helped.

NARRATOR: So, what's feeling bad?

LARRY: My entire body. I just feel like my...just feel like my energy level, you know, the meter just went all the way to the ground.

MIRIAM NELSON: Larry really had a lot of problems, and, to be frank, I was worried about him, because of his history and just because even under...anybody under those circumstances....He was pale and a little light-headed.

NARRATOR: But it's not Larry's heart that's causing problems, it's his appetite. He hasn't been eating quite enough before and during his long training runs.

MIRIAM NELSON: His fuel sources were spent, and that's what was getting to him. He just had no reserves.

NARRATOR: The fuel we run on is a chemical cocktail containing both fat and carbohydrate.

ROGER FIELDING: Even very lean people have a very large reserve of fat that we can burn for energy, and a very limited reserve of carbohydrate or sugars stored in the muscle.

NARRATOR: The carbs are stored in the muscle and liver, in a compound called glycogen.

ROGER FIELDING: You want to exercise for an hour or 90 minutes, there's plenty of glycogen in the muscle to do that thing. But, if you want to go out and run a marathon, that's four or five or six hours for some people. That's when you're really going to get into a situation where the stores of glycogen in the muscle can become nearly empty by the end of that activity.

NARRATOR: Larry exhausted his glycogen reserves, and in running terms, "hit the wall."

With the Boston Marathon looming, the possibility of hitting the wall is just one of the fears hanging over Team NOVA. Another is hot weather. Though April is usually cool in Boston, some years the temperature spikes into the '80s, making an already grueling course that much tougher.

But when the big day arrives, it becomes clear that heat will not be an issue.

The night before, a nor'easter with high winds and heavy rains blows through New England.

The Boston race, the oldest marathon in the country, has never been cancelled because of weather. But this time, it comes close. At 5 a.m., the decision is made: the race is on.

Twenty-six miles west of Boston is the staging area for the start of the race in Hopkinton.

Before they can start, non-elite runners like Team NOVA must wait hours in the rain and cold.

SAMA: It's really muddy, and it's horrible, but I'm excited.

XENIA: I can't wait to get started. My anxiety is so big.

STEVE DEOSSIE: I have no idea what I'm doing out here.

DON MEGERLE: Adios. Goodbye. Be good now, be good.

NARRATOR: The Boston Marathon has several starting guns.

At 9:25 a.m., it's the wheelchair division; next, the elite women runners; at 10, the elite men and some of the 20,000 qualifiers—runners with a fast enough time in a previous marathon. Only then does Team NOVA move into the starting corrals.

RAY: We're going to do this.

JANE: I know.

STEVE DEOSSIE: Can you guys hear the Abba on my iTunes coming through? Because I don't want to come off like I'm listening to Abba or Broadway show tunes or anything like that.

UTA PIPPIG: Xenia! Sama! Are you all relaxed? Yay!

SAMA: We can do it!

NARRATOR: Finally, at 10:30 a.m., 40 weeks of preparation are put to the test.

UTA PIPPIG: Go for it, guys! Good luck!

NARRATOR: The Boston Marathon course, stretching across eight towns and cities, is considered one of the toughest in the world. The first part of the course is downhill: punishing for the legs and a temptation to run too fast in all the excitement.

At the nine-mile mark, Coach Don awaits his runners, but feels upbeat about the team's start.

DON MEGERLE: They were looking like they were going to a dance before the start of the run, honest to God. Hopefully, they're coming by with some expressions of joy as opposed to discomfort or pain or anything like that.

Doing good. You're doing good. It's a piece of cake!

STEVE DEOSSIE: Oh, yeah, for you maybe!

NARRATOR: Also there to greet the runners is the lone member of Team NOVA that failed to make it to the starting line, Melissa.

MELISSA: I'm very excited for the team, and I'm so impressed that they all made it, but it's really hard not to be among them.

SAMA: I'm feeling great!

CAROL: I'm fine. I'm fine.

NARRATOR: On the second half of the course, runners begin to pay the price for early mistakes.

DANIEL: I went out too fast.

DON MEGERLE: Are you slowed down now?

DANIEL: I'm hurting. I'm going very slow now.

NARRATOR: The first four NOVA runners are headed for a climb, several miles of grueling hills, culminating in the notorious Heartbreak Hill in Newton, 20 miles into the race. It's a spot where plenty of past competitors have hit the wall.

When the NOVA runners reach the top, they get some final advice.

UTA PIPPIG: Short steps, short steps.

Tuck behind someone!

Good job! Come on.

Stay relaxed.

DANIEL: I feel like I'm there. I'm going to make it. I know I will. Uta, thank you! I love you!

NARRATOR: From here, it's all downhill. Still, for exhausted runners, the last six miles are almost always the hardest.

Coach Don is waiting nervously at the finish line. A little less than four hours after the start, almost two hours behind the winners, Jonathan appears. His parents are in the stands to cheer him on.

JONATHAN'S PARENTS: Is that Jon? There he is! Hey!

JONATHAN'S MOTHER: I think it's great!

MIRIAM NELSON: Well done. Well done! That's fabulous!

NARRATOR: The other three NOVA frontrunners are about a half hour behind.

RAY'S FAMILY: Raymond! Raymond!

You did it!

DANIEL: I could take a nice big drink and a couple of hip replacements. Emotionally? Good, very good. I just completed a marathon.

NARRATOR: Back on the course, things aren't going well for Steve, though he's spurred on by his daughter. His Achilles tendon is acting up. Pushed too far, an Achilles tendon can actually snap during a race.

In the training runs Betsey's time has always been better than Steve's, but not today. A urinary tract infection is taking its toll.

BETSEY: We're going to go for it. It's now or never, right?

NARRATOR: Farther back is Sama, struggling through the same injuries that prevented her from ever running more than 16 miles.

Behind her is Vera, who's had to walk since the halfway mark. She has a sharp pain in her left foot that will later turn out to be a piece of glass.

For Vera, Sama and the remaining NOVA team, running or walking, it's now just about finishing.

JANE: Otherwise, I have no aches or pain.

NARRATOR: Five and half hours into the race, with parts of the course opening up to traffic, for the rest of Team NOVA the struggle ends, as one by one, they come home.

JONATHAN: All right, Xenia! Go, go!

NARRATOR: It's a remarkable achievement for Team NOVA: 13 entered training, 12 made it to the starting line and all of them finish.