Written By Sam Smith

Can you predict the competitive success of CrossFit athletes based on the measurement of lean body mass ratios and forced expiratory volume? OPEX Head Coach Sam Smith sheds some light on his findings and research in the subject.

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Society places great stock in the art of measuring one’s future success. SAT, ACT scores and IQ tests are supposed to correlate with one’s ability to be successful in school. Logic holds that if you do well in one, you must do well in the other. While there’s nothing inherently wrong with these indirect measurements of success they are still an indirect method. The only way to validate these indirect measurements findings is to collect more relevant data.

We at OPEX have been collecting our own data to develop specific indirect measurements of success in the sport. One of these such measurements involves the usage of a InBody body composition machine. This machine uses 3 different pieces of information to drive accurate readings:

1. Direct Segmental Multi-Frequency Bioelectrical Impedance Analysis (DSM-BIA): Views the human body as five cylinders: left arm, right arm, left leg, right leg and the trunk. InBody provides independent measurements for each cylinder to provide accurate measurements for the entire body.

2. 8-Point Tactile Electrode System with Thumb Electrodes: When measuring impedance with electrodes, contact resistance occurs. InBody accounts for contact resistance by strategically placing electrodes to accurately measure impedance in the body.

3. Multiple Frequencies: Electric currents penetrate differently, depending on the frequency. Some frequencies are better suited for measuring body water outside the cell, while others can pass through cell membranes to measure total body water. InBody uses multiple currents at varying frequencies to provide the most precise body water analysis.

These pieces of technology give out a reading that includes: intra and extra cellular water, lean body mass, upper and lower body amounts, total fat mass, dry mass, proportional lean mass, total weight, and gives the person their Basal Metabolic Rate.

After collecting thousands of readings over the last 6 years, we’ve condensed our data into 100 readings from competitive level athletes in the sport (Games Athletes, Regional Athletes, and top 100 in the Open for both Male and Female). 

The first metric we look at is the ratio between upper body lean mass and lower body lean mass. These values are given to the athlete on an InBody print out that includes all the other data points mentioned above. The upper body lean mass includes: Left Arm, Right Arm, and Trunk. The lower body lean mass incudes: Left and Right Leg. We take these two values and divide the upper lean mass value versus the lower lean mass value to get a score. The numerical number we have seen as a baseline for great distribution of lean mass relative to the demands in the Sport of Fitness is: 2.0.

To create a clear understanding of what and how this is calculated, here’s an example:

Athlete A has 109.83 pounds of LBM in their upper region (Left Arm, Right Arm, Trunk). Athlete A also has 54.39 pounds of LBM in their lower region (Left Leg, Right Leg). Thus, 109.83 (Upper LBM) / 54.39 (Lower LBM) = 2.02 (Ratio)

Based off our own in-house research, we have seen a trend of those who reach higher levels of success have an Upper to Lower Body LBM ratio of 2.0 or greater. The reason why this is important is due to the demands on the body that CrossFit creates. It is not uncommon for an individual competitor to have to do over 100 upper body dynamic contractions in a workout, rest 2 days, repeat the same effort and aim for improvement.

To give a concrete example, last year’s CrossFit Open workout 17.4 had 55 Handstand Push Ups (HSPU) as the last movement in the 13-minute chipper-style workout. If someone scored within the top 100 in the South Region on that workout, they would have averaged at least 50 HSPU for the females and at least 55 HSPU for the males. It was not uncommon for individuals to “re-do” that workout 2-3 days later and aim for a higher score. That would leave people performing over 100 HSPU, potentially 150+ if they did it 3 times, within a 72-hour period. Under metabolic stress, psychological stress and cardiovascular stress, that’s a lot of work and load placed upon the pressing muscles, as they are the primary drivers in the HSPU. Along with a well-built aerobic system to increase their speed of recovery between the intensive workouts, the leaner mass someone has surrounding the neck, shoulders, scapula, triceps, the better able they would be to handle that volume of repetitions.

From a mechanical model perspective, if we had two athletes who had these specific anthropometrics:

Athlete 1: 6’0, 225 pounds, 195.3 pounds of LBM, with a wingspan LONGER than his height

Vs.

Athlete 2: 5’7’’, 175 pounds, 152.8 pounds of LBM, with a wing span SHORTER than his height

Now let’s compare these frames with a HSPU. Athlete 1 would NEED great lean mass around the upper chest/neck/shoulders/scapula/triceps to SUPPORT the added lean mass he must work with in addition to the added range of motion his body would have to travel each repetition due to his longer wing span (aka, arm length). If Athlete 1 had less LBM in his upper quarter, his system would arguably not be able to support his structure along with the volume of repetitions needed to succeed in the sport.

As a side note, cases where we see highly competitive athletes in the sport who have a wing span LONGER than their total height (IE- Tennil Reed, 6th place at the 2017 Crossfit Games) they also have extremely strong and robust pressing and pushing abilities to counteract their added range of motion. A few numbers to highlight this point, Tennil, who weighs 160 pounds and is 5’6’’, can Close Grip Bench Press 220#, Strict Press 145# for 3 reps, and can perform over 70 strict HSPU in 5 minutes.

The main takeaways here are:

1. We have been monitoring Upper to Lower Body Lean Mass and have seen correlations over time of 2.0 or greater with those who have had success in the sport.

2. From a mechanical perspective, it would be prudent, given the demands of the sport (as mentioned above), those who have longer wingspans, relative to total body height, will need more lean mass in their upper quarter to potentially stay competitive with those who have shorter wingspans.

Our second metric is the ratio of Lean Body Mass (LBM) divided by FEV6 (Forced Expiratory Volume, 6 seconds). This ratio is looking at how much lean mass must be fueled relative to lung volume. The FEV6 measurement is the amount of air exhaled in a forced breath that last for 6 seconds. We use a nSpire PiKo-6 Electronic FEV1 / FEV6 Meter device. With regards to accuracy in measurement, this piece of equipment has a “4% or 0.1 L accuracy, whichever is greater.”

We use the 6 second value (FEV 6) to get an accurate representation of how much lung volume someone has available to them. The closer an athlete is to the lowest levels we have seen (i.e.- 23-24 lbs of LBM/liter), the better off they will be, relatively speaking, not absolutely. The separating value we look for is 30 lbs. of LBM/liter. Empirically, we’ve found that having a value of 30 or less sets an athlete up well with enough oxygen to support the LBM they have. If someone was to have a value above 30, say 38, we would then say they have too much LBM relative to their lung volume. Thus, we would have to improve their muscles’ ability to use O2 by becoming more efficient due to less availability.

You can also think of it as, there is less room for error due to less total volume of O2 available. Therefore, they will need to accumulate lots of contractions that stay below the threshold. Without getting to complex, think: keeping them below THEIR “redline” and able to continually cycle through those movements for extended periods of time. If these athletes get too close or go over their ventilator threshold, they will: start to slow down significantly in cycle rate, get “hot” temperature wise and will have to start breaking up sets more than necessary to prevent failing repetitions. These are all indirect measures of the athlete starting to burn too much sugar (from a physiological perspective) and is now moving away from MAINLY using aerobic metabolism as the primary fuel source. Thus, the work is now becoming “unsustainable” and entering “into fatigue” based sets/training.

An additional tool that needs to be practiced and implemented in various progressive states with those who have a score above 30 is practicing increased rate of breathing.

To give an indirect account of measurement (as we are assuming they can get O2 to the muscle WELL, which isn’t guaranteed), if someone has to do a 10-min piece of work, and we tell them to increase their breaths per min by 10 at 2.5 liters per breath (a conservative amount), that’s 100 extra breaths, and 250 liters, of oxygen they are getting within that 10-min piece of work. For an athlete who has limited oxygen available to their muscles, an extra 100 breaths could be the difference between qualifying or not qualifying for regionals.

As I mentioned above, the idea of increased rate of breathing needs to be practiced and implemented in various progressive states. A prudent way of slowly introducing this into your training and building a greater connection with your breathing as you exercise would be to start with cyclical modalities. For Example:

5-7 sets for play and learning:
1 min Assault Bike @ 75-90% (Building pace)
1 min Walk

IE-
1st set: 60 RPM
2nd set: 62 RPM
3rd set: 64 RPM
4th set: 66 RPM
5th set: 68 RPM
7th set: 70 RPM (90ish % effort for the individual)

Each set you will increase your pace by 2-3 RPM. All the while focusing on your breathing. As you increase the cadence, make a conscious effort to increase your rate of breathing by 3-5 breaths per min. I wouldn’t get too caught up in the fine details as you begin this journey. Focus more so on consciously breathing and increasing it as the pace increases. FEELING the control, you gain OVER the piece of work by using your breath to dictate the direction of eat set.

It’s important to mention, there is a negative connotation with increasing your rate of breathing (IE- you’ll accumulate more CO2, you’ll increase anxiety, etc.). We at OPEX have NOT found this to be true in CrossFit. We cannot speak on this in other sports or disciplines, but within our world and what we’ve seen over the last decade, increased rate of breathing has been a performance “enhancer” for majority of the athletes we’ve worked with. It goes without saying, no other sport has the open system, chaotic demands, that fitness has and the infinite variations in the types of contractions imposed upon the individual. More O2 in = More potential O2 to the working muscles.

We’ve also seen an increase in confidence in athletes as they move through pieces of work due to “controlling” the workout with their breathing. As the “intensity” or “speed” of the contractions increases, rate of breathing needs to accommodate for this. Once athletes become more attuned to their breathing and ACCEPTING of this higher rate, they will have a greater sense of control over the workout versus the workout controlling them.

Standard Measuring Procedures for above mentioned tests:

InBody: Their website: https://inbodyusa.com/pages/technology
(for more information on product and purchasing)

When collecting Inbody readings, we want repeatability and consistency for each test we run:

1. Same time of day on the same day each week or month (depending on how frequent someone tests)

2. Same amount of food and liquid before the test each time

3. Preferably NO caffeine before taking the test

4. Preferably a bowel movement before taking the test

5. For Females, 19th-21st of their cycle

6. Socks, shoes, watches, wrist bands, jackets should be off (shorts, shirt, bare minimum on is best)

Piko6: The model we use: https://www.quickmedical.com/nspire/piko-6-peak-flow-meter.html
(for more information on product and purchasing)

When collecting FEV readings:

1. Utilize disposable cardboard mouthpiece attachments

   1. Demonstrate for the athlete how to take in a FULL breath of air originating in the diaphragm before exhaling as strong as they can finishing in a bent over position

   2. Remind them that the reading accounts for 6 seconds so continue exhaling (as some people will probably stop too early)

   3. Give them 3 attempts to acquire their best result (give them as much rest as they need between efforts. For those who’ve never done it before, they’ll probably get their best score on the last one as they quickly figure out how to maximize their inhalation and exhalation. For those who have done it before, they’ll probably get their best score on the first one)

In closing, having a greater understanding of where your client sits regarding their upper and lower lean mass proportion will help provide an additional measurement of what needs to be prioritized in their program relative to their goals. In conjunction, looking at an athlete’s lung volume relative to their lean mass will also give insight into how efficient they will have to be with oxygen utilization and if specific mechanisms need to be implemented into their program design.

We are continually collecting data and presenting what we find to improve our athlete’s performance in CrossFit and to be at the forefront in Scientific Research within the sport.

CrossFit® is a registered trademark of CrossFit, Inc. OPEX Fitness’s uses of the CrossFit® mark are not endorsed by nor approved by CrossFit, Inc., and OPEX Fitness is in no way affiliated with nor endorsed by CrossFit, Inc.