We recently published a paper in the Journal of Clinical Densitometry (Dengel et al., 2020) on body composition measures in over 590 NCAA Division I collegiate male and female track and field athletes. There is a wealth of information in the article and I encourage you to read it if you want a more detailed look at the data in this blog posting. In the first blog post, we discussed the male data that was part of the article, and this blog will focus on the female data that was contained in the article.
As many of you are aware track and field is a very unique sport in that it is made up of a number of events (i.e., shot put, sprints, long distance, pole vault, etc.) that require a specific set of skills. In addition, a number of track and field events favor athletes that have a very distinct body type and composition. In general, most track and field athletes try to maximize their fat to muscle ratio, however, the optimal total mass for each event is highly variable. For example, some events like shot put may favor athletes with large amounts of total mass as well as lean muscle mass while events such as distance running may want to limit to the total body mass. Unfortunately, by trying to limit overall total mass, distance runners may actually put their bone health at risk. Therefore, it is not only important to monitor fat and muscle masses but also monitor bone health, which may be compromised when athletes try to limit their total body mass. Dual X-ray absorptiometry (DXA) is the perfect tool to examine body composition in this population since it allows for the determination of fat and lean muscle masses as well as bone mineral density (BMD). DXA also allows for assessment of regional composition which is important in events that focus on a particular part of the body such as jumpers and throwers where asymmetries may develop due to training loads placed on the different regions of the body.
The article (Dengel et al., 2020) we recently published is unique in that it contains data from male and female collegiate track and field athletes from all of the events. So let’s look at the female track and field athletes that were scanned from 4 different NCAA Division I Universities and were classified into one of seven categories: Jumpers (i.e., long jump, triple jump, high jump) (n=30); Long Distance Runners (i.e., 5,000, 10,000 meters and 3,000-meter steeplechase) (n=110), Middle Distance Runners (i.e., 800 and 1500 meters) (n=24), Multi-Event Athletes (n=9), Pole-Vaulters (PV; n=27), Sprinters (i.e., 100, 200 400 meters, and 100, 110 and 400-meter hurdles) (n=96), and Throwers (i.e., shot put, discus, javelin) (n=20). Multi-Event Athletes were individuals who competed in the heptathlon (i.e., 100-meter hurdles, long jump, shot put, high jump, 200 meters, javelin, and 800 meters). All DXA scans were done between September and December.
Physical characteristics of female collegiate track and field athletes (Table 1).
The physical characteristics (i.e., age, height, weight, and body mass index [BMI]) of the female athletes by event are compared in Table 1. Since these were all collegiate track and field athletes their age was similar across events. In looking at just weight, as you would expect throwers were heavier than their counterparts. Based on standard body mass index (BMI) categories sprinters, middle- and long-distance runners, jumpers, pole-vaulters, and multi-event athletes would be classified as normal (BMI: 18.5-24.9 kg/m2). Throwers, on the other hand, would be classified as obese (BMI: 25.0-29.9 kg/m2). The throwers being classified as obese is unsurprising and illustrates the problem with using BMI as a way to classify athletes, especially those athletes that are large and carry a lot of muscle mass. We saw the same issue in male throwers being classified obese when using BMI.
Total body composition measures of female collegiate track and field athletes (Table 2).
In Table 2 the total body composition averages by event for the track and field athletes are presented. When these track and field athletes are classified by total percent body fat (%fat), female throwers would be considered overweight (%fat: 31-36%) while female sprinters, middle- and long-distance runners, jumpers, pole vaulters and multi-event athletes would be classified as good (%fat: 16-23%) (Jeukendrup & Gleeson, 2019). None of the female track and field athletes were considered athletic (%fat: 8-15%) (Jeukendrup & Gleeson, 2019). This was exactly what we saw in the male track and field athletes when we examined their percent fat values by event. It is important to note that these classifications were based on two-component body composition methods (i.e., hydrostatic weighing and skinfolds), while the current study’s values were produced from a three-component body composition method (i.e., DXA). A two-component model of body composition has to assume the mass of the bones while a three-component model of body composition actually measures the mass of the bones. This improves the accuracy of the three-component method of body composition over the two-component method of body composition but also illustrates why there are differences between the two methods. Table 2 also contains the total weight of the bones (BMC: bone mineral content) for our female track and field athletes. Not surprising is the fact that female long-distance runners had a lower total BMC in comparison to their track and field counterparts, while throwers had a significantly greater total BMC than their counterparts. Again, we found these same trends for total BMC in our male track and field athletes. This illustrates the problem with assuming that the mass of bones for athletes or anyone is the same. There are a number of different factors that can affect the mass of bones [BMC] and therefore assuming everyone has the same BMC can lead to error in accuracy in percent fat when using a two-component method to measure body composition.
Total and regional measures of bone mineral density for female collegiate track and field athletes (Table 3).
Mean total and regional measures of BMD for the sample are presented in Table 3. BMD is the amount of bone mineral in bone tissue. While BMC and BMD sound like the same thing, they are really two different measurements of bone. For example, two athletes, who weigh the same, but are different in regards to height, may have identical BMC values for their total body or for a particular region. However, the shorter athlete may have a higher total BMD when compared to the taller athlete at the same weight. BMD is often used clinically to assess the risk of osteoporosis. While a very low BMD doesn’t predict a fracture, it may indicate if an individual is at a greater risk for a fracture. The data presented in Table 3 shows that the total BMD measurements for long-distance runners were significantly lower than BMD values for other track and field athletes. Throwers had significantly greater total BMD values compared to other female track and field athletes except for sprinters and multi-event athletes. For most regional (i.e., spine, pelvis, leg, and arm) measures of BMD, throwers had significantly greater BMD values, while long-distance runners had significantly lower regional BMD values than their track and field counterparts. These same trends in both total and regional BMD were observed in our male track and field athletes.
What does it all mean?
As this blog posting points out there are some significant total and regional body composition differences across events for female track and field athletes. These differences may be due to the unique demands of each event. When you combine the data presented in this blog post with our previous blog post concerning body composition in male track and field athletes you have a very complete picture of both male and female NCAA Division I collegiate track and field athletes. The data provide a guide for coaches and trainers when evaluating both male and female track and field athletes. As complete as this article is regarding body composition in track and field athletes, one should not consider this the end to the discussion on body composition in male and female track and field athletes. There still is room to expand upon this study by examining seasonal changes in body composition in this athletic population. This may prove to be very interesting given that a lot of long-distance athletes also compete in cross-country in the fall and transition into indoor track during the winter and outdoor track in the spring, while some athletes only compete in the winter indoor and spring outdoor track seasons. Following these different athletes with different schedules will provide trainers and coaches with more information to make adaptions to training for a competitive season for track and field athletes by event.
For those who want more detailed information, I refer you to the original paper (Dengel et al., 2020), which this blog post is based on. I also urge you to read the companion blog post on NCAA Division I collegiate male track and field athletes. If you have questions regarding this blog post or the original paper (Dengel et al., 2020), that this blog post is based on please contact the corresponding author Dr. Don Dengel (e-mail: firstname.lastname@example.org).
Dengel DR, Keller KA, Stanforth PR, Oliver JM, Carbuhn A, Bosch TA: Body composition and bone mineral density of division 1 collegiate track and field athletes, a consortium of college athlete research (C-CAR) study. Journal of Clinical Densitometry 23(2):303-313, 2020.
Jeukendrup A, Gleeson M. 2019 Sport Nutrition. 3rd ed. Champaign, IL: Human Kinetic; 2019.
About the Author
Donald Dengel, Ph.D., is a Professor in the School of Kinesiology at the University of Minnesota and is a co-founder of Dexalytics. He serves as the Director of the Laboratory of Integrative Human Physiology, which provides clinical vascular, metabolic, exercise and body composition testing for researchers across the University of Minnesota.