Engine, Chassis, and Springs
I have found, as I’m sure has every senior runner, that long and steep hills present an increasing challenge in races and training. Some actually like hills — I have always tolerated them at best. But now, they have become both a physical and mental barrier. When approaching a hill I try incanting an internal pep talk. That works to some degree on short hills with a moderate grade. But when a hill or series of hills goes on for 400 meters or more (sometimes much more!) I am in survival mode. I start counting steps or target landmarks just ahead. Neither of those things help all that much and when I finally crest the hill, I’m usually sufficiently wasted such that making an immediate increase in speed on the downhill is unassured.
So, I’ve been thinking about the components of our physiology that enable us to climb those hills and how these components change with age. Using a passenger car as an analogy to our running, I thought about the function of the engine, chassis, and springs that both enable and enhance our car’s ability to motor up hills.
A car’s engine is the source of power. As fuel is burned, the engine transforms chemical energy into mechanical energy, which through the transmission moves the wheels. Our running engine is essentially our cardiorespiratory system (see Chapter 6 of Senior Distance Running Essentials), which includes our heart, lungs, and the blood vessels that move oxygen and nutrients into our muscles and then extract carbon dioxide. It’s well known that maximal heart rate declines with age along with a reduced absorption of oxygen and nutrients followed by a slower removal of wastes. All of this affects our ability to push it on hills. The rate of decline has proven to be quite individual. However, research has shown that continual aerobic training with a high level of frequency, intensity, and time (F.I.T.) can decrease that rate by about 50%.
An issue we face is that when we are out of action for any period of time, this capacity falls rather quickly and is harder to regain in our senior years. Yet, the good news is by engaging in other aerobic activities such as cycling, swimming, water running, StairMaster, rowing, and elliptical at a vigorous level, we can retain much of this function ou\tside of running. So, we do what we can by factoring in F.I.T. as able.
The chassis is our car’s frame plus the suspension and brakes. The engine connects to it and the wheels and springs extend from it. In our bodies this might correlate to the combined network of bones, muscles, and nerves. How the body works is clearly more complicated than an automobile as our bodily components are much more dynamic. Yet, the function is similar: in a car the chassis provides a solid base for the moving parts; in the body, our bones, muscles, and nerves both enable and conduct movement.
In a car, regular maintenance keeps the chassis from rusting, while some components, such as the suspension and brakes may need periodic replacement. As we age, research tells us our bones thin, muscle cell quality and density declines, and transmission of signals along the nervous system slows. Again, we have an active role in retaining function. Resistance training for all parts of the body, some of it maximal, is essential. Another thing that tends to happen is a lessening of intensity and duration of training. Notice I left out frequency. Many senior runners try to train as many days as they did when younger but find they cannot train as hard or long without incurring injury. What to do?
Of the F.I.T. factors, F. is deemed the least important. If we retain a high level of effort three times a week rather than say five (I’m assuming a couple of days of lower-level training in both cases), we will retain more of our top-end capacity than if we short-shrift the intensity and duration. Consider the conundrum we face with hills: we need that top-end to attack those hills. Long, slow runs will not adequately prepare us. And if our goal is to run a credible half marathon, a bunch of six- to eight-mile runs are not going to enable us to race a strong 13 miles, which invariably includes hills. So, here again we are faced with some biological realities, yet we have some ability to mitigate the changes by keeping up with our intensity and duration.
The springs of a car not only dampen the shock of meeting the road but also increase the car’s traction to the road. This leads to a safer, more enjoyable trip as well as more efficient use of fuel. Our joints and connective tissues function this way as well, though they do so much more. When a car’s coil springs compress, the car can ride unevenly on the road leading to tire wear and damage to the suspension. In runners, an uneven distribution of weight can result in failing joints, which can then lead to hip or knee replacements.
As complex as joints are (see Chapter 4 of SDRE), it is the protective connective tissues (primarily ligaments, tendons, and fascia) as well as strong muscles surrounding these joints that allow for sustained, stable movement. When we sprain an ankle or tear an ACL, the joint is subject to forces that interfere with normal movement. And once our connective tissues are compromised, they tear more easily, leaving joints less protected. This is particularly dangerous on downhills, where the torque from gravity can magnify the ground reaction force imposed on our joints.
We might not think of water as a cushioning agent. But it plays a key role in our bodies. The water content in connective tissues varies from 25% in bone to 75% in collagen, but with age the water content in all tissues declines by as much as 10%. We can hydrate, and that helps, but there still is cross-linkage of collagen fibers (as discussed in SDRE Chapter 3) that results in reduced water retention. Dryer tissues are subject to stiffness and a greater chance for injury. “Thanks a lot,” you might say — “tell us what we can do!” For starters, stretching and flexibility exercises are important to incorporate. Foam rolling is an easy addition as well as balancing on one leg or on a BOSU ball. These activities all enhance circulation and thus help maintain hydration in our connective tissues. Finally, resistance exercises shore up the muscles surrounding joints, creating a protective sheath that also encourages water retention.
Maybe I’m stretching it to use this car analogy. Yet our bodies, much like our vehicles, can last a long time with proper care. When it comes to ascending the hills, there is regrettably no magic elixir that will take us back 30 years when we might recall gaining on the field on the hills rather than hanging on for dear life! So, once again, we do what we can to keep our bodies in shape to meet the challenges we encounter in races. And we will also be taking our cars in for regular maintenance so the engine, chassis, and springs are in good working order!