by Juli Huddleston
For 99% of the world’s population, running a marathon is merely a twinkle in the eye. For the select, elite, crazy 1% of the population who have completed this 26.2 miles “race”, it is a life-changing event- a satisfying, bragging-rights accomplishment- and an excuse to eat two dinners and have an extra dessert.
When an individual decides they want to attempt the marathon challenge, they face months (or sometimes years) of physiological changes before successfully crossing the finishing line. During marathon training, or any long-distance endurance activity, the body will adapt to become the most efficient system possible. This means improving utilization of oxygen for maximum metabolic performance. If this sounds overwhelming, don’t worry! The Tufts President’s Marathon Challenge (PMC) can help anyone who wishes to undergo training and complete a marathon.
Tufts PMC is the “largest known collegiate marathon program in the US”, as stated by the John Hancock Center on Physical Activity and Aging at Tufts University. It was started in 2003 by current Tufts President Lawerence Bacow. Don Megerle, coach of the PMC team since 2004, has coached, motivated, and cheered-on 200 Boston marathon runners each year. Any Tufts student, staff, alumni, or friend of Tufts can sign up for a spot on the PMC team (online at www.tuftsmarathonchallenge.com). Training runs start in September and continue over a 23-week program that ends on Patriots Day, the date of the Boston Marathon. Everyone can train with the PMC team, however only 200 bib numbers (given to the team under contract by The Boston Athletic Association) are given out. Student runners raise $1,000 and all other PMC runners raise $2,500 each for a bib number. The bib numbers are assigned according to academic standing and dedication to training. All money raised goes towards Tufts University.
Since its inauguration, the PMC team has raised over $2.3 million for nutrition, fitness and health research and programs at Tufts University. Last year, over $428,000 was raised by the team, as stated on the Tufts PMC website. The majority of the money went towards childhood obesity research at the Friedman School of Nutritional Science and Policy conducted by Christine Economos. The rest went to the Personalized Performance Program on Tufts Medford campus. This program is run under the Sports Medicine Department at Tufts and teaches students how to be individual and group exercise trainers.
Training Your Body:
Physiological changes that occur during endurance training are not necessarily visible. Coach Megerle notes most changes he sees among the PMC runners are mental and psychological in nature, as members improve their fitness and realize their potential. Underneath the “runners high” however, the body is working hard to improve performance. According to Sjodin & Svedenhag, in their article Applied Physiology of Marathon Running, three factors combine to determine an individual’s running ability. These include maximum oxygen uptake, efficient oxygen use, and amount of oxygen needed. Genetics determines to what degree these three factors may improve, which means that each individual has an upper limit to training.
Anaerobic Threshold and Energy Use:
The highest predictor of marathon performance is anaerobic threshold, as explained by Sjodin & Svedenhag. This is the body’s change in macronutrient fuel source with increased intensity of activity. At lower levels of exercise, the body will use fat stores as its main form of energy; as the intensity of exercise increases, the body will utilize carbohydrate stores more than fat. A high anaerobic threshold means the body can continue to use metabolic pathways that require oxygen (aerobic pathways) for longer and at higher intensities. This is called being in a steady-state. Once the anaerobic threshold is reached, the amount of oxygen a person breathes in is not enough to maintain aerobic pathways for energy production and alternative fuel sources must be used. Physically speaking, the person is “out of breath”. This is called the anaerobic state; it is less efficient and cannot be maintained for long periods of time. Therefore, an individual’s anaerobic threshold determines the speed that that person can run at for long distances.
A study by Ramsbottom et al. entitled Training induced physiological and metabolic changes associated with improvements in running performance, looked at physiological changes during endurance training in undergraduate male athletes. After participating in a short-term steady-state endurance program, the subjects improved their maximum oxygen uptake and oxygen uptake per second. This allowed the students to use oxygen more efficiently in order to maintain an aerobic state for longer periods of time and at higher intensities. Thus, their anaerobic threshold was increased. This was demonstrated by each student improving their pre-training 5k running pace.
Glycogen stores (sugar in the form of glucose in the muscle) provide energy to the body during all activity. These stores are limited, however, and will deplete during long bouts of exercise; they must be replaced by the next best fuel source, fat. Not surprisingly, Sjodin & Svedenhag report that marathon runners have a higher turnover to fat metabolism at higher intensities compared with other runners. Marathon runners are able to utilize fat stores better in order to slow depletion of glycogen stores.
Marathon Physiology Research at Tufts:
During the 2008-09 PMC training season, several PMC runners participated in a pilot research study looking at body weight change during marathon training, headed by Doctoral student Mary Kennedy of the Friedman School. This study measured height and weight and compiled survey data on training and eating habits as well as individual motivation for running. The study included 64 individuals from the PMC team, the Arthritis Foundation, Liver Foundation, and Community Running Club marathon teams in Boston. The abstract for Kennedy’s pilot study will be presented at the American College of Sports Medicine conference this June.
Opposite to common assumption, marathon runners typically maintain or increase their body weight throughout training. This observation has many theoretical explanations, such as gaining lean mass (which weights more than fat), increased carbohydrate stores in the form of glycogen, increased fluid intake, and increased caloric consumption to balance increased energy expenditure during training. Kennedy’s study results and future research on this subject will hopefully add to the limited evidence on this subject.
Improving General Health through Training:
Kennedy has run 11 marathons herself, including the Boston Marathon with the PMC team in 2006. She has also been a marathon coach for the Arthritis Foundation’s Joint in Motion Charity Team since 2004. “I love to help people gain the confidence to complete a marathon, both physically and emotionally” she says. Kennedy comments that everyone can benefit from marathon training. The physiological changes that occur not only help with marathon performance; they make everyday activities easier, too. Kennedy concludes that if a marathon is a goal of yours then you should consider joining the PMC team. “The team offers a good atmosphere and a ton of support to help you accomplish your goal safely and successfully,” she says.
Over 930 PMC runners have crossed the finish line of one of the most prestigious marathons in the world. Comparing this to the size of the Tufts community, the odds of being in the 1% of the world’s population who can call themselves marathon runners are increased tenfold! According to Coach Megerle, once you go through marathon training with the PMC team, “you can do anything!”