Progress Tracking via Body Composition

By Katy Meassick, MA, RD, CSSD, LDN, ATC

Being able to track progress and show validation of a service or product is a key component in almost any facet of work. This statement is especially true for both nutrition and strength practitioners and programs where numbers or photos can clearly exhibit development. One common way to track progress within strength and nutrition is measuring body composition changes. Assessing body composition gives insight into how the athlete’s body is responding to programming over time, if they’re being compliant on their own, and allows practitioners to adjust programs accordingly over time.

Importance of Measurement

When looking at just a number on the scale, what is actually behind it? Body weight can be a great way to monitor weekly progress, but it doesn’t tell the whole story and should not be the lone tracker of habit change and program progress. Dangers could arise while only using body weight as a measure for weight gain, weight loss, or strength programs. In conjunction with strength-based information like bar speeds and GPS statistics, body composition measurements can help round out the data to show a bigger picture. Validated fitness markers can help any practitioner build a better performance plan. With the addition of lean body mass, athletes could see an increase in durability, endurance, power, and strength. On the other hand, uninformed weight loss could be counterproductive. An athlete may be achieving overall weight loss, but what is actually being lost? Losing muscle and bone mass could be predictors of future performance and injuries; while gaining undesirable fat mass could be a predictor of overall health and performance status.

Which modality is right for you?

There are several modalities on the market that provide different levels of measurement.  Review of current program procedures is a great starting place to see which technique could improve the process and fit well within the program. Initial cost, maintenance, practitioner training requirements, and ease of use are all points that should be considered prior to investing in a new modality.

Skinfold calipers are a great entry point for adding body composition measurements to a program. They are lower cost, convenient and transportable, and can be of low inconvenience to the athlete. This method has been validated for athlete outcomes when practitioner training and practice ultimately lead to precise and accurate measurements. When using skinfold measurements to predict percent body fat, it is important to choose equations that are representative of the population being measured and assure equipment is calibrated. Repetition of accuracy is difficult when measuring a high number of athletes, so it’s ideal to have a couple staff members proficient in taking standardized measurements.

Bioelectrical Impedance Analysis (BIA) and Ultrasound are non-invasive methods of measurement. BIA is the measurement of total body water which is converted to fat free mass determined by passing an electrical current through the body, measuring the tissue resistance to the current. BIA is convenient and non-invasive, and tools can vary widely in cost and what they measure. It also may not be sensitive to small changes; sometimes as a practitioner, we need to show those small changes. Body water content plays a major role in the results of BIA. Adding in a hydration status marker such as urine specific gravity may assist in consistent results, though may cause the testing period to be cumbersome.

The ultrasound method is a higher cost tool than previous mentioned modalities. The tool has a short testing period and is also capable of compartmental measurements, which could be helpful in a post-surgical rehabilitation setting. As a newer modality, the measurements are not yet standardized and, in most cases, a trained technician may be necessary.

The BodPod is one of the most widely used and known modality amongst collegiate programs. It uses air-displacement to calculate body composition based on assumption of value constants for fat mass and fat-free mass densities. Although a quick measurement period of 3-5 minutes, the BodPod requires the athlete to prepare for the test by being fasted of food, water, and exercise along with dressing in spandex and tying up hair. Movement outside the machine can also impact the result of the test. All controllable factors should be noted and repeated during the next test. If these standardized methods are achieved, the BodPod has been shown to have a high reliability resulting in accurate data measurements. Many athletes have been introduced to the machine and its methods which is helpful. Furthermore, the test is easy to run, and results are also easy to interpret.

All above modalities are two-compartment models, they measure and compare fat and fat-free mass. Another method, DEXA (dual energy x-ray absorptiometry), provides a third compartment in bone mineral content. The measurement of bone density allows for a larger picture of the athletes’ overall health. The bone density capability allows for screening of osteoporosis and osteopenia. The DEXA is highly accurate and non-invasive. One commonly cited hesitation with using DEXA machines revolves around radiation; however, contrary to popular belief, the radiation levels that the machine does emit are extremely low. Each state has its own set of radiation protocols, some may require a radiological technician which could be a hurdle to some programs. This modality does need larger space with a closed door and comes with a higher price tag. Compared to the prior mentioned modalities, the DEXA provides results that allow for comparison of limbs, great for injury rehabilitation monitoring.

Each modality has its pros and cons, finding the right fit for your program may require collaboration with other departments and analyzing the benefits of each method. Collaborating with and consulting the members within your respective sports medicine, nutrition, strength and conditioning, and administrative departments may be ideal for helping select the right modality to best suit the needs of your athletes. It can come down to money, but showing the long-term investment, how healthcare of athletes is evolving, along with potential areas for athlete programming improvements are all great ways to increase awareness and interest.

Frequency of Testing

Frequency of testing is impacted by number of athletes, number of trained practitioners, availability of modality, and availability of athletes. Every athlete should have a baseline test, it would be best to capture this when the athlete first joins the team. Testing incrementally throughout the season is ideal. Incremental measurements help monitor athletes’ progress as well as spot any potential issues, like changes in bone density or high rates of muscle loss. Four measurements throughout a season can help determine rates of muscle loss and allow for time to make appropriate nutrition interventions. Muscle and weight loss during a season do not have to be an accepted trend as body composition measurements can help guide seasonal programming to help keep muscle intact and thereby increase durability.

Working with athletes during a body weight change? The focus should be on an overall body composition change. It’s ideal to retain as much lean mass on a weight loss athlete as possible and regular body composition measurements can ensure muscle retention is as high as possible. The same can be said for an athlete trying to quickly gain a lot of weight, as rapid weight gain can be harmful to overall health and joint health. Precise, regular measurements can provide monitoring to ensure the athlete is building muscle at an acceptable rate.

Additionally, monitoring an athlete’s return to play can be useful during rehabilitation from a surgery or significant injury. Having the baseline test is key to ensuring the athlete’s lean body mass returns within range of initial measurement. For example, if rehabbing from an ACL reconstruction, comparing right to left limbs can be useful in conjunction with quad and calf muscle girth measurements. Skinfold calipers, ultrasound, and DEXA would be ideal for these comparisons. BodPod and BIA could ensure the athlete’s total lean mass has returned to baseline. Number of measurements during rehab, again, is determined by the program’s allowance. Ideally, measuring monthly would give great insight to how the athlete is responding to the rehab program.

All in all, the frequency of measurements is dependent on the program and its needs. Some programs may test at the start and end of the season and twice in the off-season – making it a four time of year testing protocol. Others might test four times during the playing season. Any amount of measurement can provide valuable insight to programming.

Final Thoughts

No matter the modality or the measurement frequency, adding body composition testing to your program can provide better understanding to the athlete’s response towards the programs in place. It is valuable to monitor an athlete’s progress during any body weight change; the focus should be on overall composition change. Each modality has its pros and cons, but all provide benefits. Along the side of monitoring body weight change, regularly measuring body composition can guide a more effective program, both in nutrition and strength and conditioning. When interpreting results, it is important to remember how vulnerable some athletes can be when it comes to their body weight and body composition. Body composition measurements should be treated as medical information and used for program guidance. It is important to discuss result distribution, amongst the performance team, prior to adding testing into a program. Administration should be on board for all protocols and athletes should have final say on the sharing of any numbers. Properly communicating the benefits and protocol to the athlete, prior to measuring, is best practice. Finally, after each testing session, a results discussion amongst the performance staff can be helpful to identify any potential issues and examine success stories.


This article was written by a Collegiate and Professional Sports Dietitian Association Registered Dietitian (RD).  To learn more about sports nutrition and CPSDA, go to www.sportsrd.org


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