Comment from James FitzGerald at Optimum Performance Training

We were fortunate enough to receive an interesting and insightful set of comments from James FitzGerald of Optimum Performance Training (OPT) about our post on the Work Capacity Curve. If you don’t know who James is and what OPT is about you should check them out, they’ve done some amazing work in the health and fitness area and training athletes of every caliber and walk of life. Below is our response to his comments.

First off, thank you for your comments! I’ll try to answer it as best I can (italicized comments are from James).

not sure how in regards to “work” how 1 push up is a score of 3200 and i HSPU is a score of 1500, as well a 2 legged squat scoring 6000 and a pistol on one leg scoring 4000.

So based on our estimates (or what we’ve been able to find in the literature or from other references) work for 1 push-up, in terms of movement of center of mass (COM) is approximately the same as the work for 1 handstand push-up (HSPU). Similarly for 1 vs. 2 leg squat. The values you mentioned represent the total work per round for each movement. (5 HSPU vs 10 Pushups — results in 1500 vs 3200).

to me in just “knowing what it feels like” – there are levers and loading that is NOT included in your explanation of how to determine “work” done in these movements – if its COM and distance covered – this makes sense in measuring those things that can be measured like chin up and thruster (possibly…) –

This is absolutely true, the work calculations we provide do not directly capture this information. Someone may be perfectly capable of doing push-ups, but unable to perform a HSPU. In this case, strictly based on work estimates and no other information, these movements would be deemed “equivalent” in terms of their overall level of difficulty or what they say about a person’s overall ability to do work.

Of course this really isn’t the case. What we would expect (reflected in our analysis of athletes data) is that a person who is capable of performing (more) HSPU’s should, in principle, be able to perform more regular push-ups (or movements involving similar major muscle groups) than a person who is not able to do (or can only do a few) HSPUs. There is definitely a skill/technique component with HSPU’s, so this may not always be the case. However, on average we would expect that the person capable of performing (more) HSPU’s to be able to perform more work faster when HSPU’s or any related movements are involved. So in terms of comparative analysis these things will still play out.

Things like movement difficulty can be directly captured by looking across a population of similar individuals (in terms of height, weight, age, gender) and evaluating the effect of a particular movement on work output/time.

but in running, rowing, double unders, muscle ups, KBS, TGU, power snatch, squat snatch, power clean (or power clean slight squat, power clean full squat, power clean no squat) the movements cannot be simplified into weight over distance as everyone is different and EACH REP is different – therefore the movements if picked cannot be used to estimate “relative” work

I agree, to an extent. Our aim with these types of movements is to obtain a general estimate of work. For example, with the Olympic lifts we can approximate the length of the bar path based on an athlete’s height and use this to estimate work. There is a fair amount of research published on this, and we use this information in our work estimates. That being said, technique is going to play an enormous role. Just because someone is 5’9’’ and weighs 210 lbs doesn’t mean they can move a bar as efficiently or as explosively as Ilya Ilin. Additionally, if you were to take a look at the distribution of limb lengths amongst the population of people who were 5’9’’, Ilya’s would likely be very different. Thus, as before, a person who is able to move more efficiently will be able, in general to do more work faster. So for population based analyses we are able to make statements about how these movements affect an athlete’s performance on a given workout.

As far as some of the other movements you mentioned (and other similar ones), we generally rely on average distance travelled, or pace of the run/row, etc. So, for example, the skill associated with something like double unders is certainly going to play an important role in calculating work output. Someone who is very efficient at this movement may only jump about 2 inches at each skip, by comparison someone who isn’t as efficient may be jumping upwards of a foot (and missing a bunch reps as well). In our calculations of something like this we take the “average” (loosely speaking here) and assume that most people will jump about 6 inches per skip. As above efficiency in movement plays itself out in a person’s ability to complete more work (e.g. more double unders) faster as compared to their peers.

i just simply remember what it took to complete 21 rounds of Mary as my PR, and weeks prior did 32 rds of Cindy – and honestly (of course based on training this can make a difference and I am open to that) – Mary kicked the shit out of me – so if power was SIGNIFICANTLY lower, don’t you think there would be the feeling of less work done over that time of 20 min…

I think that this will vary on an individual-by-individual and workout-by-workout basis (21/32 rounds is just ridiculous by the way :)). I can honestly say the most painful variant Cindy I’ve ever done was back at Sections in 2010, it was with a 20 lbs weight vest (I think)… I can’t remember the exact number of rounds I did but I think it was somewhere around 17 (I’ll try to find my results). At the time my Cindy PR was around 24 rounds. The amount of work for the weighted Cindy is about 225,000 ft-lbs and unweighted is about 300,000 ft-lbs and I have to say I’d take unweighted over weighted any day. My point is that though there is probably a correlation between amount of work done and how painful a workout is, I don’t think that this is necessarily the case across the board.

the chart on lowered work output over time has been around since the 50′s when the milers needed an upgrade in their prescription and the German movement of intervals took precedent – therefore requiring some insight into why someone who sprints for 2 min cannot keep this pace for 20 min – but to argue work within that time frame over time for a chaotic, unknowable system is truly admirable, but very tough to do…

I’d be very interested in reading up about this, if you happen to have any recommendations/ references it’d be greatly appreciated! In terms of modeling the work output over these time durations, yes there is absolutely a great deal variation and noise, both from our estimates of work, as well as the various complexities affecting an athlete’s performance on a given workout on a given day. What we do see is that as an athlete enters more workouts, general and systematic trends begin to appear. It’s these trends that we’re interested in studying and providing feedback on.

I hope these generally answer your questions. We’re always looking for better ways of capturing and analyzing athletes performances and we would love to get your thoughts about any ideas you might have about how to do this. Thank you again!


Site Overview Part 1

Greetings everyone from the team at Science Behind Sweat!! This post has been a long time coming and will hopefully provide you with an adequate update of various features on the site. Recently we’ve made a lot of changes to improve functionality and give people better information on the drivers of their fitness. In particular, we’ve modified work output calculations, developed new analytics (soon to be widely released!), and have added and will be adding a host of other updates and features. Today I’d like to talk about the specifics of our work output calculations so people can better interpret what they’re seeing when they look at their Work Capacity chart and Fitness Scores. Ultimately, we want you to have a full understanding of all of our features and how they feed into our analytics but for now we begin by laying the foundation.  So let’s start with calculating work output.

Work output

One of the key goals of CrossFit is to maximize an athlete’s ability to do work over broad time and model domains. From a practical standpoint, this could mean anything from shoveling snow off your driveway to battling renegade ninja’s or carrying Uncle Lou to bed after he’s had one too one too many wine spritzers.

How do we take these varying daily activities or exercises like squats, dead-lifts, pull-ups, bosu-ball squats (= terrible idea) and meaningfully quantify them?  To do this we have to calculate or at least estimate the amount of work it takes to perform all the movements in each activity or exercise in terms of foot-pounds (ft-lbs) of force.  Once all work estimates are calculated for each movement, we can then figure out the total work done.

As an example, let’s take your average statistician (aka, myself).

Build: Height: 6’1”, Weight: 215 lbs.

Workout: Cindy.  This is a 20-minute AMRAP (as many rounds as possible); 1 round = 5 pull-ups, 10 push-ups, 15 squats.  I have to do as many rounds as I can in 20 minutes.

Work Estimate (per movement):

1 pull-up = 570 ft-lbs x 5 = 2850 ft-lbs

1 push-up = 320 ft-lbs x 10 = 3200 ft-lbs

1 squat = 400 ft-lbs x 15 = 6000 ft-lbs

1 round of Cindy = 12,050 ft-lbs

With my PR (personal record) for Cindy being 27 rounds the total work done is 325,350 ft-lbs or 12,050 ft-lbs x 27.

This feeds into our analytics in two important ways…

1) We can break down activities into key movements and calculate work estimates for a variety of different workouts while also tracking the amount of time it takes to complete a workout.

2) We can plot work output vs. time to get an idea of your ability to do work over broad time and model domains.

In our next post, we’ll talk about the work capacity chart which will draw on some concepts that we discussed in this blog.  Please don’t hesitate to provide feedback, post comments on Facebook, or send us an email with any questions.

Remember we are here to help you train smarter!!