On Saturdays after wrapping up working with clients and hanging out at IFAST, I usually spend lunch with Rufus (AKA Grant Gardis), Lance, and the interns chatting over fajitas and a margarita. Conversation is always varied and will cover a full spectrum from relationship advice to high-level sports training and sciency stuff.
Rufus had to leave, so we skipped Mexican food this past Saturday, but I was lucky to have a conversation with my buddy, former IFAST intern, former IFAST employee, photographic memoried and current standout physical therapy student Eric Oetter. I try to touch base with him regularly just to see how he’s doing and to see what they’re currently studying in his classes. It’s a great way for me to keep up on the basic sciences as Emory’s program appears to be outstanding in that capacity.
Recently, Eric attended a lecture by Randy Trumbauer, PhD regarding his research in brain-derived neurotrophic factor (BDNF). If you don’t know anything about BDNF, John Ratey, MD refers to it “nourishes neurons like fertilizer” in his book SPARK. It is present in the brain, more specifically the hippocampus, an important area for memory and learning.
The research that was presented was more specifically regarding the BDNF Val66Met allele.
[Allele – an alternative form of a gene.]
An interesting point of the research on the Val66Met allele of BDNF, which is present in about 25% of the population, is that it has been shown to REDUCE motor learning and motor map reorganization following motor task training (think learning any physical activity).
The Val66Met allele of BDNF is also implicated in depressive and anxiety disorders per Trumbauer’s presentation. Research also indicates that those with the Val66Met allele demonstrate a significantly higher anticipatory stress response.
The influence of genetics on skilled or sports performance, rehab from musculoskeletal or neurologic injury, and young athlete development certainly presents some very interesting questions. Here’s some thoughts from our conversation this Saturday afternoon…
After suffering a stroke, traumatic brain injury, or spinal cord injury, does the Val66Met allele impact a patient’s outcome in regard to recovering motor abilities? It would certainly seem that it may. The limited ability to develop new neurons and new connections in the brain or spinal cord after an insult could certainly limit recovery potential. This may account for the broad variations in recovery seen by patients suffering neurologic injuries.
Does the Val66Met allele impact one’s abilities to learn or demonstrate new motor skills in athletes? This is a conversation (actually several conversations) that I’ve had with Rufus recently regarding young athlete development. Take 100 kids and watch them play or exercise. There are certainly broad variations in performance. Is this the genetic component that influences or limits ultimate performance and separates the pros from the rest of us?
If such a genetic variation is a limiting factor, can we impact the potential negative consequences in regard to motor performance? Perhaps, yes. Hypoxic conditions and exercise can certainly increase BDNF secretion, and Eric noted per Trumbauer’s presentation, they are doing amazing things with patients with incomplete spinal cord injuries via acute intermittent hypoxic conditions.
On another interesting level, if there is an allele that limits performance by reducing motor learning and mapping the motor cortex of the brain, is there an allele that does the opposite? Is there a variation that makes learning motor skills and improving brain maps easier? Eric and I have discussed this many times. Take the highest level athletes you’ve ever seen or worked with. While there are many who present with a top-notch work ethic, there are also many who never train, occasionally practice, and yet demonstrate amazing physical skills and abilities. We’ve always said that these athletes are “just wired differently.” Perhaps this sheds light on such “wiring.”
If you’ve read books like The Sports Gene, then you’re very aware of the impact of genes on performance. For instance, a variant of the alpha-actinin-3 gene (ACTN3) in fast-twitch muscle fibers appears to be important for speed. Variations in a sodium channel-alpha subunit (SCN9A) affects our ability to experience pain by altering nociceptive inputs. One of 27 variations of SCN9A can make you less sensitive or more sensitive to noxious stimuli. (here’s a large study covering pain perception variation and SCN9A expression in a variety of conditions) Catechol-O-methyl transferase (COMT) is an enzyme that breaks down neurotransmitters in the brain like dopamine, epinephrine, and norepinephrine. Variations of the COMT gene influence cognition and memory as well as one’s sensitivity to pain, expression of anxiety and catastrophizing.
Implications and thoughts
Injury prediction, rehab potential, and human performance are multifactorial and incredibly complex. Threat perception, nociception, processing capabilities, and output capacity are all genetically influenced. We and our behaviors are products of our gene expression, but we are not our genes as how they are expressed is modifiable. Any sensory input is an influence on processing and output. The challenge is to determine the on/off switch and apply the correct inputs into the nervous system. While there are certainly commonalities amongst humans this concept is individualized.
If you’re a trainer, therapist, or coach, perhaps you should consider the thought above the next time one of your patient’s or athletes complains of what you feel is an unreasonable level of pain or physical limitation. These perceptions and limitations are individualized.
The current biopsychosocial model may not only apply to pain or disease but human performance as well. Still thinking about it.
Looking at the impact of genetics on human performance reminds me of reading about the old Soviet sport school programs where they utilized early identification of athletes and developed them utilizing a long-term, multi-year program. It would appear they were (and the concept still is) way ahead of the US athlete development programs on a much deeper, scientific level. We need long-term developmental programs for our younger athletes. Certainly, all our kids won’t be superstars but with a properly organized, long-term program their chances of improvement are much greater. The most likely result is a better human regardless of the sports-related outcome.
How does someone have one of the worst possible injuries for an NFL running back and yet come back in less than a year to have one of the greatest seasons of all time? A great team of doctors, therapists, trainers, and coaches coupled with a perfect storm of genetics and environment. Adrian Peterson may represent this scenario to a level we haven’t seen before. Always remember that human performance is multifactorial. The process, progress, and performance will always be individualized. Don’t set expectations based on the outlier.