CrossFit Injury Rate Study

Interesting study of CrossFit injury rates (Hak PT, Hodzovic E, Hickey B. The nature and prevalence of injury during CrossFit training. J Strength Cond Res. 2013 Nov 22.). The study reported on an on-line survey so it was probably quite slanted in the results.

An online questionnaire was distributed amongst international CrossFit online forums. Data collected included general demographics, training programs, injury profiles and supplement use. A total of 132 responses were collected with 97 (73.5%) having sustained an injury during CrossFit training. A total of 186 injuries were reported with 9 (7.0%) requiring surgical intervention. An injury rate of 3.1 per 1000 hours trained was calculated.




Keto Diet and Performance

tl;dr – Don’t expect to do keto, be in a large deficit,
and expect to see performance gains on glycolytic activites.

A good video on lifting and the keto diet. Covers other aspects of performance from the perspective of a real clinician and what he sees in his patient population who does keto. Very truthful even if not totally pro keto at moments (overall it is very supportive of keto so no need to be afraid of watching).


STRRIDE-AT/RT – Exercise Study

I was considering dropping CrossFit in favor of a strength program when I came across an interesting study which compared Aerobic Training (AT) to Resistance Training (RT) for impact on Metabolic Syndrome (MS). (September 15, 2011, Volume 108, Issue 6, Pages 838–844. Comparison of Aerobic Versus Resistance Exercise Training Effects on Metabolic Syndrome (from the Studies of a Targeted Risk Reduction Intervention Through Defined Exercise – STRRIDE-AT/RT. Lori A. Bateman, Cris A. Slentz, PhD, Leslie H. Willis, MS, A. Tamlyn Shields, MS, Lucy W. Piner, MS, Connie W. Bales, PhD, RD, Joseph A. Houmard, PhD, William E. Kraus, MD.)

AT/RT induced a significant improvement in the MS z score (p = 0.004) and AT alone exhibited a trend toward improvement (p <0.07). However, RT alone failed to significantly alter the MS z score.

My conclusion is to stick with CrossFit and work in the resistance training as often as reasonable as an accessory to CrossFit.

Another view of the same data (J Appl Physiol (1985). 2015 Jun 15;118(12):1474-82. The effects of aerobic, resistance, and combination training on insulin sensitivity and secretion in overweight adults from STRRIDE AT/RT: a randomized trial. Abou Assi H, Slentz CA, Mikus CR, Tanner CJ, Bateman LA, Willis LH, Shields AT, Piner LW, Penry LE, Kraus EA, Huffman KM, Bales CW, Houmard JA, Kraus WE.). Conclusion:

AT/RT resulted in greater improvements in insulin sensitivity, β-cell function (disposition index), and glucose effectiveness than either AT or RT alone (all P < 0.05). Approximately 52% of the improvement in insulin sensitivity by AT/RT was retained 14 days after the last exercise training bout. Neither AT or RT led to acute or chronic improvement in sensitivity index. In summary, only AT/RT (which required twice as much time as either alone) led to significant acute and sustained benefits in insulin sensitivity.

Yet another look at the same data (Am J Physiol Endocrinol Metab. 2011 Nov;301(5):E1033-9. doi: 10.1152/ajpendo.00291.2011. Epub 2011 Aug 16.
Effects of aerobic vs. resistance training on visceral and liver fat stores, liver enzymes, and insulin resistance by HOMA in overweight adults from STRRIDE AT/RT. Slentz CA, Bateman LA, Willis LH, Shields AT, Tanner CJ, Piner LW, Hawk VH, Muehlbauer MJ, Samsa GP, Nelson RC, Huffman KM, Bales CW, Houmard JA, Kraus WE.) concluded:

AT was more effective than RT at improving visceral fat, liver-to-spleen ratio, and total abdominal fat (all P < 0.05) and trended toward a greater reduction in liver fat score (P < 0.10). The effects of AT/RT were statistically indistinguishable from the effects of AT. These data show that, for overweight and obese individuals who want to reduce measures of visceral fat and fatty liver infiltration and improve HOMA and alanine aminotransferase, a moderate amount of aerobic exercise is the most time-efficient and effective exercise mode.

Yet another view (Arch Intern Med. 2004 Jan 12;164(1):31-9. Effects of the amount of exercise on body weight, body composition, and measures of central obesity: STRRIDE–a randomized controlled study. Slentz CA1, Duscha BD, Johnson JL, Ketchum K, Aiken LB, Samsa GP, Houmard JA, Bales CW, Kraus WE.):

In nondieting, overweight subjects, the controls gained weight, both low-amount exercise groups lost weight and fat, and the high-amount group lost more of each in a dose-response manner. These findings strongly suggest that, absent changes in diet, a higher amount of activity is necessary for weight maintenance and that the positive caloric imbalance observed in the overweight controls is small and can be reversed by a modest amount of exercise. Most individuals can accomplish this by walking 30 minutes every day.

Note none of the results were comparable to the effect on the metabolic syndrome from the Low Carb High Fat diet.

Strength Training – Starting Strength

I’ve started doing the Starting Strength program by Mark Rippetoe. The program is described in Rippetoe’s book, Starting Strength: Basic Barbell Training 3rd Edition. The program is intended to be done by people who are beginners to strength training.

Starting Strength Program

The Starting Strength Program consists of a linear progression where the weight you lift is increased every single time you lift. The program is performed 3 times per week.

I did the program starting at bar weight and am now increasing by 5 lbs. I am expecting that the rate will slow down. I do the lifts twice a week on the day before my CrossFit rest days (which are Thursdays and Sundays). I am lifting on Saturdays and Wednesdays in my home gym.

The Lifts

There are four lifts which are performed in alternating patterns. The four lifts are:

  • Back Squat
  • Bench or Overhead Press (on alternating days)
  • Deadlift

Back Squat

CrossFit places the bar high on the back. Starting Strength places the bar lower on the back.

Bench Press

This is just what you remember from your high school gym.

Overhead Press

This is rarely performed at my CrossFit box. We are usually told that any S2OH (shoulder to overhead) movement is allowed and that usually means a push press or a jerk press.


We do the deadlift at my CrossFit from time to time but not often enough to progress in the lift.

Hiring a Coach

It’s very smart to get good at lifting form before attempting heavy weights. This is necessary to avoid injuries. Starting Strength has a couple of ways of getting help with your form.

My Videos

Here’s my Starting Strength videos on YouTube. Don’t use my lifts as examples. I am still learning.


Learning the Lifts – Mirror Neurons

I really hate to memorize stuff. More than that I really hate to memorize stuff related to physical activity. Even more than that I hate to memorize weight lifting moves.

But I need to improve. I need to remember what the basics of each lift are. And there are not all that many to learn. Sure it takes years to learn the specifics of the move but the general idea is another thing.

This brings me to another concept, that of Mirror Neurons. They are the part of the brain that allows us to watch someone do something and be able to see ourselves doing that same thing. I think mine are pretty much broken.

I can watch someone do something and appreciate their athleticism. But I don’t see myself doing that same motion when I watch someone else. I think that I am seriously broken. And I think it’s a lifetime defect, not just a recent defect.

I am looking for ways to improve this. I looked for flashcards on the Olympic lifts but I can’t find any. Maybe I can make some flashcards of my own?

I’ve watched hours of videos on CrossFit YouTube channel. Same thing. I can appreciate what they do but I just don’t feel the same motions in myself when I watch them.

Plan of Attack

Lacking any other plan, here’s what I am going to do. This is based on my coaches who said I need to tape myself to see how I am doing particular movements. I am going to watch each of the CrossFit Foundational videos and record myself doing the same moves and compare the two videos. Maybe I can empathize enough with myself to fix myself.

If you have a better idea how to tackle this, let me know.

Exercise Equipment

Cast Iron Kettlebells



Power Cage

Hyper/Back Extension Ab Bench

I got more out of my first time on one of these benches than four trips to the Chiropractor.

Pullup Bar


Keto and CrossFit

It has been claimed that a Ketogenic diet is not compatible with CrossFit. The reasons most commonly given include:

  1. Some athletes who tried “low carb” have complained about performance losses
  2. CrossFit used to do Paleo and now does Zone
  3. CrossFit requires topped off Glycogen stores
  4. There are no high level athletes who consume a Ketogenic diet
  5. Ketogenic diet results in hormonal imbalances

I’d like to look at these claims one at a time.

Performance Losses on Low-Carb

Performance is a thing which is really hard to define. For CrossFit one definition of performance may be defined as the time to complete a particular combination workout such as Fran:

Three rounds, 21-15- and 9 reps, for time of:
95-pound Thruster

This is a very specific workout consisting of two movements. A Thruster is an Olympic weight lifting move down with a barbell loaded to 95 lbs total. Pull-ups are a body weight exercise with a form that is [more or less] particular to CrossFit.

The event is for time – faster is better.

The workout consists of 21-reps of the Thrusters followed by 21-reps of pullups are followed by 15 reps then 9 reps of each movement. The total time is considered the athlete’s “Fran time”.

Fran is picked as a representative set of movements and there are numerous other “benchmark” workouts (WODs) named after women (like hurricanes) and fallen warriers (the hero WODs).

These workouts allows a person to test and retest their performance over time. As a person gains strength and endurance their times will decrease (barring injury of course).

Judging Claims of Performance Losses

The claim, then, could be made that a low carb diet made someone’s Fran time longer. However, since Fran isn’t performed often it is hard to judge a diet based on Fran times and there are no studies offered of that particular metric. None of the athletes I’ve spoken with provided specific metrics for before and after the diet. Unlike other things in CrossFit which can be measured this claim is often more anecdotal than evidence based. This is important given CrossFit’s commitment to measurement as a gauge of improvement. From the man himself Greg Glassman: Understanding CrossFit:

the three most important and interdependent facets of any fitness program, can be supported only by measurable, observable, repeatable facts; i.e., data

Turns out that there actually is a specific study of this very subject. A randomized control trial (gold standard of science) was done at the James Madison University and took a mix of trained and untrained individuals and compared a group put on a Low Carb diet to another group who were not on a Low Carb diet (James Madison University. A low-carbohydrate ketogenic diet combined with six weeks of crossfit training improves body composition and performance. Rachel M. Gregory).  (Link to the complete study).

[2018-07-05 – Link to interview with Rachel on Keto for Normies podcast sheds additional light on the selection criteria.]

This study was done for the Masters Degree thesis of Rachel M Gregory in the Spring of 2016. Credit goes to BoxRox for uncovering this paper. The subjects of the study were:

Twenty-seven non-elite CrossFit subjects (mean ± SD age = 34.58 ± 9.26 years) were randomly assigned to a LCKD (males, n = 3; females, n = 9) or control (CON) (males, n = 2; females, n = 13) group.

LCKD (Low Carbohydrate Ketogenic Diet) was instructed to consume an ad libitum diet and restrict carbohydrate intake to less than 50 grams per day (<10% of total energy) and CON (Normal Diet) maintained usual dietary intake.

All subjects participated in four CrossFit training sessions per week during the 6 weeks.

The participants were measured through DEXA scans to determine body composition before and after. The results were:

Compared to the CON (Control) group, the LCKD (Low Carbohydrate Ketogenic Diet) group significantly decreased weight (0.18 ± 1.30, -3.45 ± 2.18 kg), BMI (0.07 ± 0.43, -1.13 ± 0.70 kg/m2), percent body fat (%BF) (0.01 ± 1.21, -2.60 ± 2.14%), and fat mass (FM) (0.06 ± 1.12, -2.83 ± 1.77kg), respectively. There was no significant difference in lean body mass (LBM) change between or within groups. We found no significant difference in total performance time change between the CON group and the LCKD group; however, both groups significantly decreased total performance time (CON: -41.20 ± 43.17 sec.; LCKD: -55.08 ± 44.29 sec.).

So the Low Carb group:

  • Lost more weight (about a lb a week)
  • Lost more body fat (as a percent)
  • Lost more fat mass (as lbs)

That’s not a surprise since the effectiveness of the ketogenic diet is well established. In fact, the control group actually gained a small amount of weight and body fat (the fat both as mass and a percentage). If you want to go CrossFit to lose weight, this study says it’s not going to happen. That matches the observations of some of the people I have gotten to know at CrossFit and fits other studies showing exercise doesn’t contribute much to weight loss (Diet Plus Exercise Equals Diet).

Since many and perhaps even most people get into Crossfit with the purpose of lowing weight this is a significant eye-opening finding. Six weeks of hard CrossFit with your old diet isn’t going to make you skinny.

But, Surely the Keto Dieters Performance Was Worse, Right

What is significant is the performance differences. The Low Carb group decreased their performance times (faster times) than the control group although the times were not statistically significant (because there were wide variations in both groups). The time difference (average) was 14 seconds better in the Low Carb group than the control group.

Since the scientific evidence doesn’t support performance differences how can I account for the claims of local athletes that they lost performance while on Low-Carb? The answer may be in what sort of diet these athletes were actually on.

The “Official” CrossFit Diet Used to be Paleo

Most of the athletes were on Paleo diets (Flexible Dieting: Why CrossFit Athletes are Ditching Paleo, June 23, 2016). The Paleo diet is usually a lower carb diet than the standard American Diet but it is not necessarily low carb.

For most people, the Paleo diet may not  be low enough carb to transition to fat adapted. I’ve taken a look at fat adaptation here. For example, if an athlete consumes too much fruit they may never become fat adapted. The fat adaptation process can take anywhere from weeks to months and in the transition it is widely known that performance can be lower. Additionally, cheating may result in a reset out of the ketogenic state which can take some time to re-enter. Basically, it’s a complete lifestyle change choice.

Robb Wolf states that Paleo diet:

is comprised of lean meats, seafood, fruits, vegetables, roots, shoots, tubers, nuts, and seeds.

In contrast, the Ketogenic diet excludes all fruit, many vegetables, roots, tubers and limits nuts and seeds. Each of the Paleo elements that are excluded in the Ketogenic diet are higher in carbohydrates. A Paleo person could eat potatoes and a Ketogenic person does not.

Since both diets exclude processed carbohydrates and grains they both lead to weight loss due to a net reduction in carbohydrates. Some of the people who eat Paleo also eat low enough amounts of carbohydrates to be in ketosis. Most probably don’t reach ketosis. To be in ketosis is to be fat fueled.

Failure to reach ketogenic levels is failure to access fat as the alternative fuel system.

Reference article

Glycogen as fuel

It is widely known that Ketogenic diets result in less glycogen stores in the liver and muscles. Glycogen is an energy source which can be used in intense workouts. So it would seem like having less glycogen would be a detriment in these intense sorts of workouts.

What this doesn’t take into account is that ketogenic athletes have an available fuel source that glycotic athletes lack quick access to – fat. The 6 ozs or so we have of glycogen have something like 600 calories worth of energy in them. The 30+ lbs of fat we typically have has over 100,000 calories of energy available. At least over a longer haul being fat adapted seems like a smart strategy.

For endurance athletes, being keto adapted has been well established as a benefit – see the FASTER study (Metabolism, March 2016. Metabolic characteristics of keto-adapted ultra-endurance runners. Volek, et. al.).

Peak fat oxidation was 2.3-fold higher in the LC group (1.54 ± 0.18 vs 0.67 ± 0.14 g/min; P = 0.000) and it occurred at a higher percentage of VO2max (70.3 ± 6.3 vs 54.9 ± 7.8%; P = 0.000). Mean fat oxidation during submaximal exercise was 59% higher in the LC group (1.21 ± 0.02 vs 0.76 ± 0.11 g/min; P = 0.000) corresponding to a greater relative contribution of fat (88 ± 2 vs 56 ± 8%; P = 0.000).

As to the glycogen stores:

Despite these marked differences in fuel use between LC and HC athletes, there were no significant differences in resting muscle glycogen and the level of depletion after 180 min of running (−64% from pre-exercise) and 120 min of recovery (−36% from pre-exercise).

Given that the glycogen stores in the Low Carb group were half of those in the high carb group just how relevant is the glycogen sparing effect? If two people go out to eat and one has $5 and the other had $15 and they both leave with $2.50 in their pocket could you say that the person who got less food was cash sparing? The energy comes from somewhere.

Also, the FASTER study was done at a lower %VO2max, ie, it was on a three hour endurance test, not a Crossfit 20 minute workout.

But is fat as quickly accessible as Glycogen?

Turns out fat is also very quickly accessible in these high-level fat adapted athletes. The FASTER study (Volek, et. al) compared the rte of fat and carbohydrate oxidation for the same 150 minute treadmill run. HC is High Carb and LC is Low Carb.

It is worth taking note that this study was done at a relatively low %VO2max level of effort. This contrasts with Crossfit workouts which are often done at higher intensity levels.

No Ketogenic Athletes

Given the public excommunication of Robb Wolf within CrossFit it’s not much of a surprise that there are not many top athletes who say they follow a Paleo or Ketogenic diet. That would hardly earn them the endorsement of top CrossFit personalities.

Also, these are people who would risk their health for the sake of winning (CrossFit and Steroids. Just How Juiced Is CrossFit? by John Romano | 10/16/15). If they think they can beat out the next guy by a second or two on Fran they will.

But this raises the question. Suppose it is determined that a ketogenic diet does affect performance by some small amount. A top athlete is dealing with very small percentages between herself and the next gal and is willing to risk their health. Is that the case for the average box-goer?

Also, given the very high level of training that goes into making a top CrossFit athlete they probably have a lot of wiggle-room in diet. They are burning it all off. But how many of us who do a 20 minute WOD a few days a week are doing anything like what these athletes are doing? And why should we follow their diets if we are not doing the same intense workout program?

Diet of the World’s Most Fit Woman

Digging around on the Interwebs for the diet of Katrin Davidsdottir, the winner of the 2015 CrossFit Games turns up this (This Is What the ‘Fittest Woman on Earth’ Eats Every Day  How does your diet stack up? by EMILY ABBATE August 10, 2015):

I’ve got to have my eggs, otherwise my day starts off wrong,” she says. “In an effort to get more fat in my diet for fuel, I eat half of the avocado and then the cream in my coffee.

On a good day, when she gets to eat lunch, it’ll be chicken salad and the other half of the avocado. On the days she doesn’t? “I’ll eat as soon as I finish training, and leave practice drinking coconut water with a scoop of chocolate protein powder and a serving of fruit. For dinner, I try to eat lots of dark green stuff-spinach, kale, broccoli. For protein I’ll have chicken. For dinner, which would come soon after that late lunch, I try to eat a portion of salmon for its healthy fats and vitamin D.”

Other than the single serving of fruit her diet is ketogenic. And given her workout schedule that’s not a whole lot of carbohydrates. Note that was back in 2015 (Robb Wolf’s split from CrossFit was about 2009) so this is long after that split.

So at least the world’s most fit woman eats a diet very much like a ketogenic diet, even if she doesn’t call it that.

Keto and Hormones

I am going to do a followup article on this subject.


How Much Muscle Can I Put On?

Yes, you can build muscle on a Low Carb Diet (Are dietary carbohydrates required for building muscle?).

Good article for anyone interested in starting an exercise program. Ask The Ripped Dude: ”How Much Muscle Can I Put On Naturally?”

Resources List (from the above article)

Replacing Fat with Muscle

Bayesian Bodybuilding (How can you gain muscle while losing fat & more) cites an interesting study of muscle composition (Am J Clin Nutr. 1982 Jul;36(1):131-42. Biochemical composition of muscle in normal and semistarved human subjects: relevance to anthropometric measurements. Heymsfield SB, Stevens V, Noel R, McManus C, Smith J, Nixon D.). In this paper they dissected dead bodies to determine their body composition. Of particular interest was the Protein composition and water during semi-starvation.

Here’s a calculator for Genetic Muscular Potential (YOUR Drug-Free Muscle and Strength Potential: Part 2). This is useful to know what your current condition is as well as what is possible with the most training possible.

The units are not American (lbs, inches) but are Metric (kg, cm).

I put in my numbers:

  • Height: 5′ 10.5″ = 197 cm
  • Wrist Circumference: 15.24 cm
  • Ankle Circumference: 21.6 cm

Genetic Muscular Potential Results

  • Maximum Lean Body Mass: 79 kg = 174 lbs
  • Bodyweight at Maximum Muscular Potential: 89.8 kg = 198 lbs

The Calculator goes on to tell you how far from goal you are presently. The results came back as:

  • Current body fat percentage: 19.7% (seems too low)
  • Current Lean Body Mass: 66.3 kg = 146 lbs
  • Fat mass I should lose: 5.5 kb = 12 lbs
  • Lean mass I could gain: 12.7 kg = 28 lbs

Those 28 lbs of potential lean mass would be over many years of weightlifting.