Aging: Risk, Dose and Density

Let’s review some critical points before moving on.

I’ve
been making the point, based on the aging research, that experienced senior
athletes are most likely to improve or maintain their endurance performance by
focusing on aerobic capacity and muscular strength. Such training is high
intensity. That presents the possibility of injury since older athletes are
more “fragile” than they were when younger.

There
isn’t just one way to train, however, that works for all senior athletes. The
research is drawing general conclusions based on a wide sample. Not everyone
has the same needs. The newer you are to your sport, for example, the more
likely you are to improve or maintain your performance by simply putting in
lots of training time. For the experienced athlete such training is of less
value. High intensity is likely to be more beneficial, albeit risky, for these
athletes. There are other considerations besides experience.

Your
unique individual situation must always be considered when designing a training
plan. This should take into account your age, previous training, body weight,
health, sensitivity to training stress, risk of injury, time available for
training, the goal event, training partners and much more. Then there are the
environmental factors where you live and train to consider, such as altitude,
terrain, weather, training venue availability and on and on. Even if aerobic
capacity and strength training are right for you physiologically, some of these
factors may interfere with such training.

Aerobic
capacity training may also not be your limiter. The other determiners of
endurance performance are lactate threshold and economy. Let’s do a quick
review of all three so you can draw a conclusion as to which you most need to
address in your training. The best way to determine your training needs for
each of these is to be tested for VO2max and ask the technician for a comparison of your data relative to other athletes of various ages. Such tests are often available at
medical clinics; universities; health clubs; running, bike and triathlon shops;
and are often offered as a service by coaches. Expect to spend at least US$150
for such a test.

Here
is a very brief summary of each (click on the links to read more details to help
determine what your major limiter may be).

• Aerobic capacity (VO2max) – how much oxygen
  your body is capable of utilizing at maximal aerobic effort to produce energy.
  The higher this is, the greater your potential for high performance. In
  experienced athletes, this responds best to workouts that are done at or
  slightly below VO2max.
• Lactate threshold – at what percentage of
  VO2max do you begin to “redline” due to increasing acidity. May also be
  referred to by the tester as anaerobic threshold, functional threshold, maximum
  lactate steady state, and other names. Be sure to ask for a definition. The
  higher the LT percentage is relative to VO2max, the better your endurance
  performance is likely to be. An LT between 80 and 90% of VO2max is common in fit athletes of all ages. Again, similar to aerobic capacity, in experienced
  athletes the most affective training to elevate LT is to do workouts at or
  slightly below LT.
• Economy – how efficiently you use
  oxygen (a proxy for energy) to produce movement. As economy of movement
  improves, you race faster or use less energy at any given submaximal effort.
  It’s very difficult to improve economy in highly experienced athletes, but high
  intensity has been shown to be effective (Gunnarsson).

In
previous posts (here, here, and here) I’ve discussed these three
endurance performance markers and their likelihood to be at the root of a
performance decline as you get older. I’m of the opinion that a great portion
(most?) of your loss over time is largely due to things you have some degree of
control over.

But back to testing… If
you’d rather not spend the money (I couldn’t blame you) you may just
want to accept that you fit the description of the experienced senior athlete
found in most of the research I’ve been reviewing. In that case you could draw
the conclusion that aerobic capacity is your major limiter and address it in
your training. More than likely, that’s what you would find out through
testing.

So
why not the other two? In the above posts I made the case that economy is
likely not the limiter for most senior athletes as many years of training for a
given sport has a tendency to refine and optimize one’s movement patterns. The
same goes for lactate threshold as it’s been shown to be at a higher percentage
of older athletes’ aerobic capacities than that of young athletes. That leaves
aerobic capacity. Several studies have shown this to be the one we geezers have
the greatest need to improve. It appears to decline for many reasons – some mix
of age- and training-related causes.

Then
there’s the matter of muscle loss that typically comes with aging and may also play a role in the decline of
your race results over a long period of time. Less muscle means less power. And
that means slower speed.

This
brings us back to what can be done to slow the losses, maintain current levels
or even improve aerobic capacity and muscle mass – again, assuming these are
limiters for you. I’ve previously proposed two solutions that both involve
high-intensity training: aerobic capacity intervals (or fartlek, hill reps, hard group workouts, etc) and weight lifting. Heavy
resistance strength training (Vale) and high-intensity aerobic capacity training
(Pritzlaff, Pritzlaff) have been shown to stimulate the production of anabolic
hormones – such as testosterone, estrogen, growth hormone and insulin-like
growth factor – at a greater rate than low-intensity training while also being
more effective for performance gains in well-trained athletes (Laursen). Such
hormones build and remodel the tissues necessary for improvements in your
aerobic capacity and muscle strength. They keep you "young."

Let’s again take a look at the risk associated with such training. High-intensity training
increases the possibility of injury due to great stress. So if you are to train
as I’m proposing here, some how you must decrease the risk. The way to do this
is to be both cautious with training load starting points, and conservative
with their increases. This comes down to what sport scientists call “dose” and
“density.”

Dose has to do with how hard a
given workout is – its duration and intensity. Duration may not be a problem
for you (although it often is for runners who may need to consider cross training on easy, recovery days). Most senior athletes I’ve known have gravitated toward doing long, rather
slow workouts. If you’re like most senior athletes, high intensity likely gets
little attention in your workouts which further increases your chances of an
injury if you bump up the training zones suddenly. To keep your risk of injury
manageable it’s important that you be conservative with high-intensity
workloads, especially when doing workouts such as aerobic capacity intervals
and heavy resistance training. That means knowing what your limits are and
staying well below them. Stop the interval session when you know you have one or
two good reps left in you. Don’t try to beat your 1-repetition max in the
weight room on your last set.

That’s
dose. Let’s examine density.

Density describes how frequently you
do these risky workouts. The more frequent the challenging workouts are done, the
greater the density and the higher your risk. Allow plenty of time between hard
sessions. When you first start training this way that may mean one such workout
in a week. That gives you six days of low-intensity to fully recover. As the
season progresses and your body slowly adapts, you may be able to make these workouts more dense,
meaning fewer recovery days between them. The older you are, the less dense
your training should probably be. A 50-year-old can typically handle more
density than a 70-year-old. The same goes for dose.

For triathletes this does not mean do multiple high-intensity aerobic capacity sessions in each sport. A senior triathlete when first starting such a training regimen may only do one such workout for the entire week. It's then best to use it for your weakest sport. Over time, more aerobic capacity sessions may be added to the week. The triathlete must also consider the risk associated with such training in each sport. For example, high-intensity swim training has a lower dose-density risk than running.