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Power to (All) the People

     I once sat in a class on power development being taught by a “master trainer,” who posed a seemingly innocent question: “Who needs power?”  The obvious answers surfaced, such as athletes and physical laborers.  When I chimed in with “seniors,” the instructor stared at me with a combination of disbelief and snide condescension.  He then asked me, “So, you would do a kettlebell swing with grandma?”  “Absolutely,” I responded, “because seniors lose a disproportionate amount of fast-twitch fibers and the ability to quickly react to a missed step to avoid falling.”  He refused to agree with me, which is fine, but I wanted to make the point to the dozens of uninitiated trainers in the room eagerly soaking in this guy’s “wisdom.”

     I could have continued building a case for why older people need power training in their programs but I didn’t want to monopolize the class.  Instead, I’ll finish my thoughts here.  Let’s consider some specific changes that occur from the ages of 30-70(1,2):

  • Muscle mass and strength decrease by 25%-30%.  In addition, Type II fibers are lost in a disproportionate amount.  Consequently, power decreases.
  • Nervous system function declines; there is a decrease in the number of total brain cells, motor unit size, and conduction velocity while synaptic delay and reaction time increase.
  • Bone density decreases between 10%-30% (women lose the most).
  • Cardiovascular capacity decreases, including the following: VO2 max, stroke volume, anaerobic power.

 

     Habits and lifestyle choices will certainly impact the severity of the decrements listed above.  The good news is that training can help offset these changes! 

74-year old Ernestine Shepherd, Guiness World Records' oldest female bodybuilder.

     However, decreases in sensory system functioning are not really trainable and they do have a significant impact on movement production.  A few examples(3):

 

  • Sensory receptors decrease, especially on the bottom of the feet, making seniors less able to take in critical information when walking or even in quiet stance.  (Big, orthopedic shoes designed for comfort and stability will mask even more sensory information)
  • Loss of 40% of vestibular hair and nerve cells in the ears, which help to sense changes in inner ear fluid (reducing kinesthetic awareness and accurate orientation in the environment).
  • Vision changes, especially in depth perception, prevent accurate assessment of the environment, increasing the likelihood of missteps and falls.

    

     Considering the vast physiological and sensory changes listed above, it becomes easier to understand how trips, falls, and overall performance declines occur in our senior population.  Therefore, movements specialists have a responsibility to not only teach them movement safety and competency, but to also progress them along the speed-power continuum.  Many trainers tend to take a more conservative, gentle approach with older clients (read: a slow tempo) as injury prevention is a prime consideration.  While I agree that we don’t want to do harm to our clients we also have to minimize their chances of getting hurt when in the real-world by practicing rapid force production.  As long as they are progressed properly there is no reason why these clients can’t become more powerful.  Even those who have physical limitations can simply speed up the tempo of whatever exercises they are able to do, resulting in increased force production and the ability to summate forces more quickly.

Some tips for implementing power training:

 

  • Increase strength.  The power equation (Power = Force x Velocity) tells us that by increasing the amount of force produced, power output will increase.
  • Increase the tempo (velocity) of each phase of a movement (concentric, eccentric) until both phases can be performed quickly and accurately.
  • Incorporate sensory cues prior to producing a rapid movement.  Just as crossing a street requires a visual stimulus (green light) to initiate the appropriate response (begin walking), have your clients respond to a stimulus (i.e. eye blink, ball bounce, hand gesture) before squatting, lunging, pulling, or pressing.

     To me, the most salient example of why power training is so important relates to walking pace.  Research has been done on the timing of traffic lights to allow pedestrians to safely walk from one curb to the other in an intersection.  New Haven, CT, East Boston, MA, and Los Angeles, CA are among some of the cities that have lights timed to allow a person to cover an intersection while walking at a pace of 1.22m/s (4 ft/s)(4).  However, over 96% of subjects involved in multiple studies walked slower than 1.22m/s, putting them at risk every time they crossed the street(5).  In my hometown of New York City, I cringe when I see impatient cars bearing down on slow walkers, hoping for a safe outcome for the pedestrian.  I use that image to fuel my work with my over-60 clients.  They don’t need to move quickly all the time but that ability needs to be at their disposal when necessary.

     If we keep in mind the demands of real-world situations we can better prepare our clients to be successful at those tasks.  Empower them by incorporating power into their programs.

Keep on Movin’

-CA

 

References:

 

1 Gabbard, C.P. (2008). Lifelong Motor Development (5th ed.). San Francisco, CA: Pearson Benjamin Cummings.
2 Brooks, G.A., Fahey, T.D., & Baldwin, K.M. (2005). Exercise Physiology: Human Bioenergetics and Its Applications (4th ed.). New York, NY: McGraw Hill.
3 Shumway-Cook, A., & Woollacott, M.H. (2007). Motor Control: Translating Research into Clinical Practice (3rd ed.). Philadelphia, PA: Lippincott Williams & Wilkins.
4 Hoxie, R.E, & Rubenstein L.Z. (1994). Are Older Pedestrians Allowed Enough Time to Cross Intersections Safely? Journal of the American Geriatric Society. 42, 241-244.
5Langlois, J.A., Keyl, P.M., Guralniik, J.M., Foley, D.J., Marottoli, R.A., & Wallace, R.B. (1997). Characteristics of Older Pedestrians Who Have Difficulty Crossing the Street. American Journal of Public Health, 87(3), 393-397.

3 comments

  1. jay says:

    Hi Carolyn, your argument makes sense and i know you are mainly dealing with physical training and i know you mentioned habits and lifestyle. however, i don’t think you elaborate enough on the most important aspect of diet and nutrition as the fuel to create this power. for me, any workout routine begins and ends with fuel. and i think if this aspect isn’t addressed in conjunction with exercise there is potential for harm because most of the ill informed will just go pick up a dumbbell (weights) and think they are on the road to health and strength. as i stated earlier, I understand your focus but i don’t think the subjects can be separated, especially with seniors, most of whom have depleted so many of the bodies nutrients that the body starts shutting down on itself. I believe power begins in the mind. And understanding how diet and nutrition create that power is too important not to discuss.

    thank you

  2. Ted Recitas says:

    Excellent post and I cannot agree with you more.

    It is imperative that trainers, coaches, movement specialist, therapist…etc., understand the application of power and how that fits within a training program. More importantly, that movement velocity is part of skill development and that skill development is part of movement education. We, the professionals listed above, need to educate the performer so that the performer can increase the velocity of their movement through force application. Thereby, increase their power output.

    Again Excellent read with a plethora of salient and practical points

    T

    1. carolynappel says:

      Thanks for your comment, Coach T. You are right that we have a responsibility to educate our clients about the whys and hows of moving more quickly. It’s not just some esoteric training idea that we try out in the lab of the gym but a real-world need that gets called upon every day.

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