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.

 

 

 

Fat Burning – Running vs Cycling

In a previous post I took at look at the exercise intensity which produced the maximum fat oxidation rates (Maximal Fat Oxidation Rates in an Athletic Population). A study took a look at the fat oxidation rates which happen when exercise is performed at the FATmax rate with cycling and running.

There was a significant difference in the rate of fat oxidation between the two (Juul Achten, Michelle C Venables, Asker E Jeukendrup. Fat oxidation rates are higher during running compared with cycling over a wide range of intensities. Metabolism, Volume 52, Issue 6, June 2003, Pages 747-752.).

Maximal fat oxidation was 28% higher when walking [ed: did they mean running?] compared with cycling, but the intensity, which elicits maximal fat oxidation, is not different between these 2 exercise modes.

These are interesting results. Although both exercises were done at the same intensity level (as measured by heart rate) they resulted in different amounts of total fat oxidation.

This leads me to conclude that although cycling and running can be both done at the MAF heart rate they are not equal for fat oxidation rates.

What About Rowing?

It would be interesting to see what the fat oxidation rate at FATmax is for rowing (ROW) and other modes. Turns out there’s a study for that too. (Egan B, Ashley DT, Kennedy E, O’Connor PL, O’Gorman DJ. Higher rate of fat oxidation during rowing compared with cycling ergometer exercise across a range of exercise intensities. Scand J Med Sci Sports. 2016 Jun;26(6):630-7. The study found that:

…FATox is higher during ROW compared with CYC exercise across a range of exercise intensities matched for energy expenditure…

The details show:

Despite similar oxygen consumption, rates of fat oxidation (FATox ) were ∼45% higher during ROW compared with CYC (P < 0.05) across a range of power output increments.

The crossover point for substrate utilization occurred at a higher relative exercise intensity for ROW than CYC (57.8 ± 2.1 vs 42.1 ± 3.6%VO2peak , P < 0.05).

Putting the Pieces Together

  • Rowing is ~45% better than cycling.
  • Running is ~28% better than cycling.
  • Rowing should be ~17% better than running.

Mechanism to Explain Differences

The degree to which an exercise engages muscles determines the maximum fat oxidation. Rowing has more muscle involvement than running which has more muscle involvement than cycling.

 

 

 

FATmax Training Results

In principle, training at FATmax (Maximal Fat Oxidation Rates in an Athletic Population) should result in significant loss of body fat and the resulting improvement in body composition. However, it is something of a surprise just how few studies have been performed to determine the effectiveness of this type of training. A meta-analysis (A. J. Romain, et.al. Physical Activity Targeted at Maximal Lipid Oxidation: A Meta-Analysis. (J Nutr Metab. 2012; 2012: 285395.) took a look and only found 15 total studies of this subject which fit their criteria. These studies were relatively small but the results were encouraging.

This meta-analysis confirms the conclusions of the individual studies, that are very low intensity training targeted at the level of maximal fat oxidation significantly decreases body weight, fat mass, waist circumference and total cholesterol. On the average, the effects of this variety of training are thus well confirmed, and their average magnitude is more precisely described.

Study Limitations

Only 5 studies include a control (nonexercising) group. There were also no longer term studies.

Volume of Training

Interestingly, some studies demonstrated an important average weight loss (8 kg over two months) with a protocol based on 90 min/day exercise at the level of maximal lipid oxidation. This could suggest that large weekly volumes of exercise training may be much more efficient than those used usually (i.e, 3 × 45 min/week).

Loss of Visceral Fat

The study called out a reference paper (Ohkawara K, et.al. A dose-response relation between aerobic exercise and visceral fat reduction: systematic review of clinical trials. Int J Obes (Lond). 2007 Dec;31(12):1786-97. ) which indicated that there is a dose response between aerobic exercise and loss of visceral fat.

… at least 10 METs x h/w in aerobic exercise, such as brisk walking, light jogging or stationary ergometer usage, is required for visceral fat reduction, and that there is a dose-response relationship between aerobic exercise and visceral fat reduction in obese subjects without metabolic-related disorders.

 

Running Slow

I’ve taken my MAF training to a certain point where I am running a lot more than I was before but still not for very long. I’d like to be able to run the whole time – except perhaps on really steep hills like the Lincoln Brick hill.

I think the problem is that when I start running I am going too fast and my heart rate climbs too quickly. I need to work on running slower. I probably need to do this work on a track to avoid hills (I live in SW PA where it is very hilly nearly everywhere).

Here’s a video of the Niko Niko method which is very similar (Niko Niko uses a low intensity steady state training at a heart rate just below the bottom of the MAF range).

The key points in this video are:

  1. Be conscious about small steps and pitch. The woman in the video is taking steps where her shoes don’t go past the other shoe.
  2. Keep your back straight. Don’t lean forward into the run.
  3. Relax your shoulders. Your arms should move naturally.
  4. Breathe naturally.
  5. Slightly raise your chin and look far ahead of you.
  6. Be conscious about forefoot landing. Don’t land on your heels.
  7. Do not kick the ground.

There is a MAF video by Sherpa Herb along similar lines.

I am going to start working on this. I’ve been doing about three days a week with an hour or more each time so I feel like my consistency has held up.

Low Carb High Intensity Interval Training Performance

Here’s a new study that looked at the Low Carb diet and High Intensity Interval Training performance (Lukas Cipryan, Daniel J. Plews, Alessandro Ferretti, Phil B. Maffetone, and Paul B. Laursen. Effects of a 4-Week Very Low-Carbohydrate Diet on High-Intensity Interval Training Responses. J Sports Sci Med. 2018 Jun; 17(2): 259–268.).

The purpose of the study was to examine the effects of altering from habitual mixed Western-based (HD) to a very low-carbohydrate high-fat (VLCHF) diet over a 4-week timecourse on performance and physiological responses during high-intensity interval training (HIIT).

Eighteen moderately trained males (age 23.8 ± 2.1 years) consuming their HD (48 ± 13% carbohydrate, 17 ± 3% protein, 35 ± 9% fat) were assigned to 2 groups. One group was asked to remain on their HD, while the other was asked to switch to a non-standardized VLCHF diet (8 ± 3% carbohydrate, 29 ± 15% protein, 63 ± 13% fat) for 4 weeks.

Participants performed graded exercise tests (GXT) before and after the experiment, and an HIIT session (5x3min, work/rest 2:1, passive recovery, total time 34min) before, and after 2 and 4 weeks. Heart rate (HR), oxygen uptake (V̇O2), respiratory exchange ratio (RER), maximal fat oxidation rates (Fatmax) and blood lactate were measured. Total time to exhaustion (TTE) and maximal V̇O2 (V̇O2max) in the GXT increased in both groups, but between-group changes were trivial (ES ± 90% CI: -0.1 ± 0.3) and small (0.57 ± 0.5), respectively.

Between-group difference in Fatmax change (VLCHF: 0.8 ± 0.3 to 1.1 ± 0.2 g/min; HD: 0.7 ± 0.2 to 0.8 ± 0.2 g/min) was large (1.2±0.9), revealing greater increases in the VLCHF versus HD group. Between-group comparisons of mean changes in V̇O2 and HR during the HIIT sessions were trivial to small, whereas mean RER decreased more in the VLCHF group (-1.5 ± 0.1). Lactate changes between groups were unclear.

Adoption of a VLCHF diet over 4 weeks increased Fatmax and did not adversely affect TTE during the GXT or cardiorespiratory responses to HIIT compared with the HD.

I have a lot of respect for Phil Maffetone and Paul Larson. Both are long time advocates of Low Carb Athletics. Phil Maffetone coached Mark Allen to multiple wins at Kona Ironman (Mark Allen Interview: A look back at working with Phil Maffetone and what it means for today’s triathlete).

 

 

MAF at One Month-ish

I did a second MAF baseline yesterday. There was more running than the last MAF baseline. Here’s the first MAF baseline (Heart Rate Training (HRT) – Part 7). I re-crunched my data from the first MAF test. Here’s the heart rate from Strava (I only had the Samsung Watch at the time). I can see I was lower on the heart rate range than now.

Here’s the heart rate data from yesterday – the Polar Strap data.

I only had two points where I went over my MAF rate and that was for a very short time.

Here is the same data from my watch (for apples-apples comparison):

I don’t trust the glitches on both of the watch charts. Not sure what the glitch was, but other than that the data is pretty comparable on both.

Performance Increase?

The idea of MAF is that you will see a performance increase. Here’s the two MAF benchmark split times.

The two mile, three mile, and for mile splits were all about 30 seconds faster so I am making good progress in improving my aerobic fitness.

 

Nerding Out on Data

I like Strava for tracking my MAF runs but it doesn’t work well for me with my Polar Chest Heart Rate Strap (HR-7). So, I’ve switched to Polar Beat/Flow for the HR-7 strap since it’s easier to read the heart rate while running. I still use Strava along with Samsung Health. The watch sends data to Samsung Health and Samsung Health sends data to Strava. I still don’t like the result since the heart rate data gets blocky. Here’s an example:

So how did I get the data?

This is the fore-warned nerdy part. I’ve written a Python script. If you don’t know Python skip the rest of this post since I can’t support the code. If you care, the Python code is here on GitHub. Again, I can’t support the code. It uses libraries that are here.

After running the pyStravaParse code. I then open the CSV file (spreadsheet format) in LibreOffice (a Microsloth EXCEL clone). I can’t support your spreadsheet choice either.

The data looks like:

Time (secs) Lat Lon Elev Heart_Rate (bpm) HRmax (bpm) HRmin (bpm)
0 39.908913 -79.71205 323.7 93 122 112
2 39.908913 -79.71205 323.7 93 122 112

HRmax and HRmin are hard coded as string constants at the start of the code. They are based on your MAF number. They could be replaced by 180-age and 190-age.Data_Time is offset in seconds.

I then select the Time, Heart_Rate, HRmax and HRmin columns like this:

Select Insert, Chart.

Choose Chart Type – XY (Scatter) then Next.

For Data Range you should already be OK if you selected data above. The select Next.

For Data Series you should already be OK. Then select Next.

For Chart Elements enter your title, etc as below. After entering in the titles, select Finish.

You should get a result like this.

To edit the chart double click in the chart. Then right click on one of the numbers on the heart rate axis. You should then see.

Select Format Axis. Then enter your own heart rate range numbers. I selected Minimum of 80 and left the maximum at 140.

You should get something like this.

I also like to move the legend to the bottom and move the graph up a bit.

Not a bad result but it’s easy to see the blockyness of the data. The Polar strap does better. I don’t have data for that same run since I bought the Polar strap later but here’s a recent image.

Not bad!

 

MCT Oil and Athletic Performance

I read a post by a guy in a Facebook group who claims MCT oil increases his athletic performance. I questioned him and he wrote:

However, when the body fat percentage gets low, you need the fats for energy to fuel your workouts. You have to reach steady state of fat in and fat/ketones out. I don’t think I could do my noon workout without my two cups of BPC in the morning. That’s my fuel…

When I asked if it was the MCT oil or the caffeine he replied:

… it’s the fat. Caffeine does not give you the ketones that allow me to lift heavy and do 30-45 mins of elliptical. Although, when I was very fat, my body provided the fat ketones. So in a sense I’m agreeing with you. There comes a time when you need that MCT fat that the liver turns into ketones as a priority.

Unfortunately the science doesn’t back up the claims.

Study #1

Miriam E. Clegg. (2010). Medium-chain triglycerides are advantageous in promoting weight loss although not beneficial to exercise performance. International Journal of Food Sciences and Nutrition, 61:7,653-679.

Results indicate that MCT feeding is ineffective in improving exercise performance and future work should focus on the health benefits and applications of MCT.

Study #2

Damien J. Angus, Mark Hargreaves, Jane Dancey, and Mark A. Febbraio. Effect of carbohydrate or carbohydrate plus medium-chain triglyceride ingestion on cycling time trial performance. Journal of Applied Physiology. Volume 88 Issue 1. January 2000. Pages 113-119 .

These data demonstrate that carbohydrate ingestion during exercise improves 100-km TT performance compared with a sweet placebo, but the addition of MCT does not provide any further performance enhancement.

Study #3

A E Jeukendrup, J J Thielen, A J Wagenmakers, F Brouns, W H Saris; Effect of medium-chain triacylglycerol and carbohydrate ingestion during exercise on substrate utilization and subsequent cycling performance. The American Journal of Clinical Nutrition, Volume 67, Issue 3, 1 March 1998, Pages 397–404.

…ingestion of MCT had a negative effect on performance…

compared with placebo ingestion, MCT ingestion had no effect on total rates of fat or carbohydrate oxidation, nor did it affect exogenous or endogenous carbohydrate utilization. The negative effect of MCT ingestion was associated with increased gastrointestinal complaints (ie, intestinal cramping). These data suggest that large amounts of MCTs (85 g) ingested during prolonged submaximal exercise may provoke gastrointestinal problems leading to decreased exercise performance.

Study #4

Jeukendrup, A. E., A. J. M. Wagenmakers, F. Brouns, D. Halliday and W. H. M. Saris. Effects of carbohydrate (CHO) and fat supplementation on CHO metabolism during prolonged exercise. Metabolism 45(7): 915-921: 1996.

It is concluded that 29 g MCT co-ingested with CHO during 180 minutes of exercise does not influence CHO utilization or glycogen breakdown.

Other Studies

Another study found that MCT Oil increased liver size by adding fat to the liver (MCT Oil and Liver Size).