Cardio-Metabolic Profile of BJJ
Grappling, like most combat sports, is best described in fitness terms as a “repeat sprint sport.” However, what contributions of strength, power, endurance, and capacity apply? What’s an average heart rate for grappling sessions? How many calories per hour and how much recovery does it cost?
As part of my conditioning coach certification with BioForce / 8-Weeks Out, I received a Morpheus heart rate monitor (HRM). On the Morpheus challenge page they aptly write:
“More sets. More reps. More weight. More intensity. More training. That’s how our culture tells us to get in shape and stay healthy. But the reason this approach is so limiting and ultimately fails is because training is only one piece of the fitness puzzle.”
That’s especially true of combat athletes. We always want to do more. We’re the grinders, the mat rats, the social outliers, etc.
One of the best features of Morpheus is that the HRM can be worn for virtually any sport, unlike optical devices (Oura, Whoop, Apple Watch, Garmin, etc.). It is also more accurate than those types of devices, particularly at high heart rate ranges — something I’ll be testing later.
The platform itself is fascinating and informative while still having a clean interface and being easy to use. My first objective was to collect some data and develop a profile for what an “average BJJ practice” looks like in terms of heart rate zones.
Of course, this comes with the huge disclaimer that exact numerical values are specific to my heart, my gym, my training, my fitness, etc. However, there should be a general profile that can be developed in terms of estimating recovery cost, calories per hour, etc.
The average recovery cost was -13.3% / training session, or about 9% / hour. That makes a lot of sense because I tend to hit a wall at about 9-10 training hours per week.
That’s still a fairly volatile figure because as we all know, not all training sessions are created equal. Not even all “drilling” sessions / styles are equal in intensity, let alone “live” rounds.
Nevertheless, as expected, you can see in the graph below that my heart rate tends to ramp up quickly in the warm up, stay fairly low during the drilling (middle) section of class, and escalates quickly during sparring / positional training (end).
One should also notes that the specific beats-per-minute (bpm) thresholds for Morpheus’s Recovery, Conditioning, and Overload Zones changes slightly session-to-session based on recovery status, but your overall fitness will indicate a general benchmark.
For me, this looks like:
Recovery Zone: 96+ bpm
Conditioning Zone: 150+ bpm
Overload Zone: 170+ bpm
Max HR: 193 bpm (clocked, not estimated)
The structure of the training session also makes a difference. The graph above is taken from a regular “class” structure — which is mostly drilling. Below you can see the HR log for an “open mat” structure — which is mostly sparring.
You may be saying to yourself,
“That’s all well and good Austin, but how can I use this to help my training?”
I’m glad you asked! Bear with me for a minute…
Activity Tracking and Calorie Expenditure:
The usefulness or accuracy of tracking / counting calories is a topic for another day. However, suffice to say that collecting data to get an idea of your training habits and intensity (energy expenditure) is useful for any training program.
Neither Garmin or Cronometer have a “BJJ” listed as a sport, though Cronometer lists boxing and wrestling, while Garmin lists Mixed Martial Arts. Depending on the selected intensity of each, you’d have an estimated energy output of 370 - 989 calories / hour with the average being ~569 calories / hour. My data from Morpheus indicated 796 calories / hour — a 40% increase from what the other platforms listed.
Note: Part of the reason for inaccuracy in these values is that they are metabolic rather than work output estimates. That is, they include your the energy you’d have consumed just existing. One’s relative fitness also impacts the level of output (HR) you can sustain in a more energy (calorie) efficient manner.
However, Morpheus’s data is consistent with my Garmin, and other fitness watches, when my actual HR is taken into account. A moderate (strength or endurance) session may see ~500 calories / hour while keeping HR pegged at 70% or more is likely in the 700 - 800 range.
Really Nerdy and Really Useful:
Above is a plot of correlations (relationship, r) between metrics I tracked over 17 BJJ training sessions. The big hitter here is the recovery cost of each BJJ sessions (M.Recovery.Cost.BJJ). Essentially, this is how much “damage” my body took during a given training session. As mentioned earlier, it comes out to about 9-10% per hour of training.
If you’re rusty on your statistics terminology, see my "Data Availability and Disclosures” document!
Obviously a higher average heart rate correlates to more calories per hour. It’s interesting that the contributions of Recovery Zone and Overload Zone to Average HR balance each other out. However, this is not the case in terms of Recovery Cost.
This is more clear when we increase the statistical confidence interval. The key takeaway here is that the relationship between intensity and recovery demand is not linear.
Bottom Line: The harder you train, you can’t just recover more, you need to recover harder (more seriously and intentionally) as well!
The Big and Small Pictures:
We all ought to know that the less recovered we are, the harder it is to perform well. The more we try to force that outcome, the greater our risk of injury.
I’ve tried all kinds of gimmicks and equations to try and estimate the intensity of a grappling session. I’ve also tried gamifying recovery by similar means. Nothing has really stuck. RPE isn’t reliable — something I’ll cover in a later post.
I’m too good at lying to myself. I want to train, hard. I want to train, every day. The reality is that doing both is impossible. The “magic” of the Morpheus platform is recognizing that not all workouts effect your recovery score the same — some decrease it, some increase it, and to varying degrees.
What’s Next:
The $125 overhead cost for Morpheus is a fairly low barrier to entry, particularly considering the cost of injury or over-training layoffs you may otherwise experience.
The next step for me is actually following the recommended “time in zone” that Morpheus provides each week based on your training and recovery habits.
I’ll also have a lot of data analysis coming out with health, performance, and subjective vs. objective measures that I’ve been collecting for the past couple months.