Validity is a complicated concept, but is related to the “truthfulness of the measure.” For practitioners, there are two important parts, 1) Is this actually measuring what it claims to be measuring? and 2) Is this relevant to performance in my clients and athletes? This study aimed to answer those two questions in a sample of NCAA Division-1 female rowers.
First, we wanted to see if the MADE App could measure Fat-Free Mass with the same accuracy as underwater weighing. In our sample of 16 athletes, Fat-Free Mass measured using the MADE App (58.5±4.3 kg) was not different than underwater weighing (57.8±4.6 kg) (p=.10).
Fat-Free Mass measured using the MADE App was also strongly correlated with underwater weighing (r=.94). Like we talked about in our previous post (https://mymadeapp.com/blog/can-we-predict-athletic-performance-anaerobic-power/), correlations can range from -1.0 to +1.0, with values close to zero indicating a weak relationship. Values above 0.80 are described as “strong,” and other researchers describe correlations above 0.90 as “nearly perfect.”
With such strong agreement, the MADE App was able to measure Fat-Free Mass within about 1.7 kg (SEE=1.68). What does that mean? For our female users the MADE App can measure Fat-Free Mass with “IDEAL” accuracy when compared to the other methods. Below is a chart from the 2001 “Methods Recommendations on Body Composition” from the American Society of Exercise Physiologists. Let’s see how the MADE App stacks up.
Each athlete performed a graded exercise test on a treadmill with gas exchange measured with a metabolic cart for determining VO2MAX.
VO2MAX was expressed relative to Fat-Free Mass from the MADE App and underwater weighing (ml/kgFFM/min). Rowing performance was determined from timed- trials over both 2-kilometer (2K) and 6-kilometer (6K) distances on an indoor rowing ergometer.
Fat-Free Mass measured using the MADE App was moderately correlated with 2K (r=-0.59) and 6K time (r=-0.46). These correlations were similar to the correlations between Fat-Free Mass measured using underwater weighing and performance as measured using 2K (r=-0.61) and 6K time (r=-0.43).
Aerobic Performance is commonly measured using VO2MAX, which is a number the describes the maximum rate that your body can “take up” and use oxygen at the tissues to regenerate ATP (energy) to keep you moving during exercise. This can be measured as the total amount of oxygen used, expressed relative to a person’s body weight, or expressed relative to a person’s Fat-Free Mass.
When it is expressed relative to a person’s Fat-Free Mass, this can serve as a measure of “training status” because it can show how much oxygen the muscle is able to use to regenerate ATP. Below is the near-perfect correlation between VO2MAX expressed relative to Fat-Free Mass in our athletes using the MADE App and using underwater weighing.
No differences were found when comparing the strength of the correlations between the different methods. What does this mean for you? Whether you use the MADE App or Underwater Weighing, both measures are equally correlated with aerobic performance.
Deciding what technique you should use to measure body composition in you and your athletes can be tough, but it doesn’t have to be. If the MADE App can measure Fat-Free Mass, Aerobic Performance, and Training Status with the same accuracy as the underwater weighing, why not give it a shot?
These results are being presented at the 2020 National Strength and Conditioning Association Annual Meeting. We will post more details and a full link to then abstract when it is posted on their Conference Website.