Tuesday, July 9, 2013

Thoughts about Crossfit, the Denominator Effect

Every year, as a member for the editorial board for the American College of Sports Medicine's Health & Fitness journal, we are asked to fill out a survey about trends in fitness.  One of the questions was on a scale of 1-10, how "hot" a trend is Crossfit.  I said Crossfit clearly is a 10.

Like many health care practitioners, I often get a skewed perspective of new fitness trends, since I primarily see patients when they get injured.  Inevitably, as new fitness trends emerge, I will start seeing a corresponding increase in injuries.  A decade ago, I started seeing yoga injuries, followed by Zumba injuries, followed by P90X injuries, and more recently Crossfit injuries.

I think it's essential to keep in mind what I call the "Denominator Effect."  What is relevant is not the total number of injuries, but rather how many injuries I am seeing, divided by the number of people participating in that activity.  Of course, as something gains in popularity, the number of injuries will go up, but I need to know the rate of injury increase.  The other major factor- for those who are NOT injured, how much benefit are they seeing.

Let me cut to chase before going into detail- I really like Crossfit.

For those not familiar with Crossfit, it is a form of high intensity training.  High intensity training is, for those who are physically ready to handle it, arguably the single best form of exercise one can perform.  The American College of Sports Medicine recommends aerobic conditioning, strength training, balance training, flexibility training, and a training plan as part of their exercise prescription, and Crossfit is a convenient way to hit all of those exercise goals.

The typical Crossfit workout starts with a well designed warm up for 5-10 minutes, followed by 15-20 minutes of weight training (focused on classic Olympic lifts or power-lifting techniques), followed by 15-20 minutes of the "Workout of the Day" (called the "WOD" in Crossfit parlance), followed by a cool down/ stretch.

The Workout of the Day often combines different calisthenic movements for time.  For example, it may include a 200 meter sprint, followed by kettle bell swings, followed by pull-ups, then repeated, with the goal of finishing as quickly as possible.

I can't speak definitively about all Crossfits, but I have had a very positive experience at Sasquatch Crossfit in Redmond, Washington- http://sasquatchcrossfit.com/index.html.

Things I liked about the Crossfit experience:
1. Attentive care: The trainers sincerely cared about their team, and focused on creating a positive experience.  I consider myself in reasonably good shape, but I had some major deficits that needed to be addressed, particularly horrible kinesthetic awareness and hip range of motion.  I was concerned about my poor form causing an injury, but the trainers took time to work with me to enhance my form, and encouraged me to perform more simple motions so that I could develop proper range.
2. Focus on full range of motion.  One of the things that the Crossfit experience taught me was the benefit of exercising through full range.  Prior to training with Crossfit, I would encourage patients (and myself) to limit themselves through shorter arcs of motion, like half squats instead of full squats.  I was wrong.  I found that by practicing full range of motion, I dramatically improved strength in the ranges I had not previously challenged.  Perhaps more importantly, my flexibility and functional range of motion dramatically improved.
3. Supportive environment.  The team philosophy is very strong.  At Saquatch CrossFit, the owner Tim is one of the trainers, and having worked with all 4 trainers, there was a consistent quality and philosophy across the trainers.  I remember doing one particularly grueling exercise (repeated lunges with a barbell), and having Tim cheer me on from the finish line and another trainer, Everett, walk next to me to correct form and provide motivation was inspiring.  While it's theoretically possible I would be able to maintain that level of intensity on my own, but realistically I don't think I have the level of pure intrinsic motivation, and the coaches really helped in making me feel like I was part of something bigger than myself.

So those are the pros.  What are the cons?
1. Not for everyone.  The workouts are challenging, so people with low baseline levels of fitness will struggle.  I routinely found my heart rate within 80-99% of my maximum, so if you have cardiac issues, I would discuss this with your physician before starting Crossfit.  If you have musculoskeletal conditions, seeing a Board Certified Sports Medicine specialist familiar with Crossfit (..... like, of course, Garrett Hyman and I at Lake Washington Sports & Spine) can help figure out how to participate safely.
2. Knowing your limits.  With some of the exercises, it can be tempting to lift as heavy as you can.  It is much more important to focus on proper form.  In fairness to all the trainers I worked with at Crossfit, they were very attentive to this issue, but I suspect some people may be tempted to lift heavy before they learn proper form and expose themselves to injury risk.  I am a beginner, so I know I can lift heavier with bad form, but that's not my goal.
3. Inherent risks with high intensity training.  All forms of high intensity training have increased risk, so I think when assessing the risk of training for Crossfit, it really needs to be compared to other high intensity modalities like Martial Arts training, Zumba, P90X, etc.  Reviewing the scientific literature, I have seen evidence for the benefits of Crossfit (e.g., http://www.ncbi.nlm.nih.gov/pubmed/23439334), but I have not seen data on the injury rate.  In my personal opinion, I think the risk is probably on the lower end of high intensity training modalities IF you listen to your trainers.  Compared to martial arts training, you don't have as high a risk of someone else injuring you, and compared to P90X, you have supervision to assess your form.
4.Deterioration of form with fatigue.  Crossfit is tiring, so it's especially important to be attentive to form as you tire yourself out.
5. Specific areas for potential injury- all can be prevented with focus on form.
    A. The low back.  Any type of loaded flexion with twisting movements can expose the back, particularly the disks, to injury.  The back is particularly vulnerable during kettle bell swings.
    B. Knees/Hips.  You are generating  force through the "kinetic chain," so if the forces are not transmitted smoothly with proper form, both knees and hips can be injured.
    C. Shoulders: As with the knees and hips, the shoulders are the base for the kinetic chain in the upper body, and therefore care must be made to transmit forces with proper form.

Overall Thoughts and Feedback for Patients:
1. Crossfit, when done with proper form under the guidance of good trainers, can be a complete package in terms of meeting the American College of Sports Medicine's recommendations for exercise.
2. It's high intensity, so it can create better results than lower intensity exercise, but also has risk of injury inherent to all forms of high intensity exercise.
3. You need to do a realistic assessment of your capabilities, both in starting Crossfit and in advancing your loads.
4. If you are unsure of your capabilities, working with Sports Medicine physicians like those at Lake Washington Sports & Spine can help in meeting your exercise goals.




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