BY LON KILGORE
From: CrossFit Journal
The stereotypical media portrayal of aging is a person who complains of joint pain, demonstrates a restricted range of motion and moves with a slow, unsteady gait.
A well-documented correlation can be found among age, gait speed and stability: As we age, speed and stability go down (7,14). This is not in reference to athletic performance of older athletes but to walking and simple standing tasks among the general public. One part of the stereotype is seemingly supported by science.
As for range of motion in well-seasoned joints, again the literature is replete with papers that present a correlation between advancing age and reduction in flexibility (10,12). It appears that another part of the age-related stereotype is underpinned by science.
Stereotypical aging characters in books and scripts often use colorful colloquialisms to call attention to the presence of pain and how they feel about it. In the scientific literature, the association between aging and pain is present (8), but some interesting physiological and psychological quirks and inconsistencies bear more consideration than given here. Overall, the stereotypical presentation of joint pain appears to be supported by data, at least in part.
This is where it gets tricky. Stereotypes are literary and theatrical devices used to portray characters without a great deal of exposition. In the real world, stereotypes are less useful. Yet the “old” stereotype pervades society.
So does evidence suggest biology will cause us to get slower over time? Do we, as an unavoidable consequence of aging, have to retreat to smaller and smaller ranges of motion? And is pain an inevitable part of aging?
Fast on Your Feet
The wealth of data on age-related declines in movement speed is derived from observational studies of average people at various stages of life. The most common studies don’t track the same group over a lifespan; they take single snapshots of different groups at different ages and compare among them. This approach is the most common because its costs are lower and data can be provided quickly and within the span of a researcher’s career. With adequate controls and proper design, the results can be quite informative, but these results will show correlation and association between variables, not causation.
What we know: Older populations seem to walk slower than younger populations. This observation is usually manifested as a reduction in preferred walking speed from 1.53 meters per second in young adults to 1.47 meters per second in 40-year-olds to 1.44 meters per second in 60-year-olds to 1.22 meters per second in 80-year-olds (19).
Does this decrement have to occur? Probably not. Most of these papers ask the subjects to walk at their “preferred” walking speed. So this is an assessment of perception and desired work rate, not physiological capacity. Some researchers have measured maximal walking speed over a few meters’ distance. Many fewer papers have investigated maximal movement speed in the aged.
In one of these few studies, Kulmala and co-workers determined the maximal running speed of adults of varying ages (26, 61 and 78 years old) across a 5.7-meter data-capture area. They found that the younger adults had flying-sprint velocities of 9.3 meters per second, the 61-year-olds could speed along at 7.9 meters per second, and the 78-year-olds maxed out at 6.6 meters per second (15). That’s a 15 percent drop from 26 to 61 years old and another 16 percent drop from 61 to 79—29 percent total lifetime drop in maximal running speed from 26 to 78 years of age. We seem to get slower with age but are still capable of significant running speed.
Just as the Kulmala paper suggests, older individuals can still move quite quickly, and these findings aren’t restricted to the laboratory. Track-and-field results show that older and very old individuals are quite capable of moving fast. The fastest 60-meter sprint time in the world for 60-64-year-olds so far in 2018 is 7.60 seconds, and for 75-79-year-olds it’s 8.56 seconds. These velocities are similar to those reported by Kulmala; however, competitive velocities are calculated from a standing start, not the flying data capture used in the research, so the competitors had higher peak velocities at the end of the race.
We do need to note that an age-related decay is present, but it is definitely not to the inevitable and ominous levels implied in stereotypes. In fact, a small study compared sedentary aged individuals to recreationally active aged individuals and masters athletes in respect to maximal gait speed and found that you can retain more of your base movement speed if you are active (9). One caveat noted in that study: You actually have to work on retaining speed; you can’t be “recreationally active.” The researchers noted that the recreationally active group was no faster than the sedentary group, while the masters athletic group was over 17 percent faster than those who were sedentary and those who were recreationally active.
It is a certainty that you will move slower over time if you remain sedentary. It is possible that—even if you are physically or recreationally active, as recommended by popular initiatives—you might suffer exaggerated slowing. What seems to change the rate of decay is training for fitness—working progressively to develop strength, endurance and mobility. Yes, slowing with age is unavoidable, but the degree of speed decay is dependent on maintenance or regaining of fitness. It is absolutely never too late to begin or restart fitness training.
But what about the decrement in movement speed seen in aging athletes? It seems that getting slower is unavoidable.
A number of biological factors partially explain why we get slower. Muscular atrophy and sarcopenia lead to the loss of functional muscle mass beginning at around age 45 (13). Changes in structure and reduced neural function also contribute to decrements (17). These, and other occurrences, are associated with the reduction in physical capacity so frequently reported with aging. But these sources of loss can be mitigated by time in the gym (23).
Out of Range
Range of motion is important. Can we move parts of our bodies where we need to in order ambulate effectively? If we have a restricted range of motion, we are limited in our ability to interact with and move within our environment.
In this aspect, the stereotype is extreme, but the data suggests that while loss of range of motion does occur over the lifespan (18,21), the loss is likely less profound than one might expect. In fact, the loss does not appear to be large at all, with reports suggesting declines as low as 0.3 percent and up to 0.8 percent per year after 40, with some joints—(such as the shoulder and hip) more affected than others (such as the knee).
If we consider Sehl’s estimation of biological-function decay at 0.66 percent per year after age 30 as indicative of the rate of joint-function loss over time, we can begin to see that biology is robust and persistent over the lifespan (20). The loss in range of motion probably has contributing factors—likely lack of use and a sedentary lifestyle. The loss of range of motion in the sedentary occurs a little faster and to a greater extent than loss of biological function. How can we say lack of movement is a contributor? Because significant data tells us that if we move joints, or, better yet, train those joints in the quest for fitness, then we can increase range of motion (2,6). While we can’t reverse aging, we certainly can prevent excess loss of movement capacity.
Pain in the Ass
For a 60-year-old, I train a lot, and I get training-induced aches and pains. I have chronic pain that can be traced to early and late-adulthood orthopedic injuries and many more insults from a weird life. If a researcher queried me about how my pain level compared to that of my younger years, he or she would conclude that I’m probably a masochist and have been so since my teens. Working toward my limits in physical performance has always, always carried with it transient pains, adaptation to and reduction in pain, and then more training-induced pain. I am not alone in this by any means; trainees and athletes of all ages everywhere have this experience.
Pain, as a concept, has to be defined. What one person describes as “mild discomfort” another calls debilitating. Some people consider training-induced pain to be indicative of homeostatic disruption that will drive adaptation, some consider that pain indicative of injury, and some consider the pain to be an actual injury. We have to make sure everyone is operating on the same definition.
If we consider sensitivity to pressure-induced pain in experimental conditions, it appears as though age lowers the threshold to pain perception. Several studies have reported that older populations report pain at lower input compared to younger populations (4,5,8,16). While much more data is available on this topic using myriad research models with wide-ranging results, it appears that as a member of the sedentary public ages, the neural network acquires a lower pain threshold. Lower levels of input create a higher pain response. Perceiving pain at a lower threshold can affect behavior; for example, by causing fear and avoidance of circumstances that are associated with pain (24). Pain can stop us from moving if we let it.
But we also see—as we did with movement speed and range of motion—that exercise has a positive effect on reported pain. Back pain is very common globally (11). As such, it receives a huge amount of attention clinically and scientifically. A very recent meta-analysis of a spectrum of common interventions to reduce the prevalence of back pain found that exercise alone reduced back pain more than any other non-pharmaceutical intervention (22). We can see a similar positive effect on reported knee pain (1).
So if older individuals report pain when they would not have in their younger lives, and if exercise will aid in reducing the prevalence of pain, it might be tempting to push older trainees for their own good. Of course, we should by no means think the data gives us license to push older individuals deep into the dark abyss of pain. Rather, it is evidence that a trainer can’t treat a well-aged couch potato fresh off the sofa the same way he or she would treat a younger new trainee. The same goes for a trainee who was athletic 20 years ago but is trying to get back into shape after two decades of sedentarism. Older trainees perceive pain differently, and scaling and progression have to be customized to each.
Trainers need to recognize that older trainees do not have the same pain-perception characteristics as younger trainees or even the trainer him- or herself. Attention must be paid to verbal and non-verbal pain cues from the older trainee to ensure appropriate loading, progression and happiness. Modify and adapt; don’t quit.
Slowing the Effects of Time—and Inaction
With regard to speed of movement, range of motion and pain, all can be modified by training. Disuse is a powerful force in aging, one that amplifies the negative effects of inevitable biological diminishment.
We can maintain a tremendously large portion of our younger function if we simply train regularly and progressively. If we choose the couch, the end result is reduction in speed and range of motion accompanied by an increase in perceived pain. To me it seems a silly and self-defeating choice. But this is precisely the option millions of older adults select.
As we age, we tend to sit down more and do less and less. The percentage of people considered to be active enough to derive health benefits is low. Only 29 percent of the young-adult population is considered physically active to the point of gaining or maintaining endurance- and strength-related health benefits (3). But remember that “recreationally active” appears insufficient to maintain movement velocity over a lifespan.
If we look deeper at the data, at exercise habits over a lifetime, we see that as the public ages, those who actually exercise or play sports stop. That low 29 percent participation rate drops to about 23 percent by about 45 years of age. It plunges to about 15 percent around age 70 and further falls to under 9 percent as people reach their 80s. This decision to stop training or playing has a profound effect and accelerates age-related functional decay.
When we plot losses in biological function, movement speed and range of motion, and the growth of the inactive segment of the population, you can see that choosing to be sedentary is likely a large contributor to loss of movement speed (see graphic). Remember I’m showing an association here, not causality, as that data does not exist.
Fight the Stereotype
What we should take away from this discussion is that noticeable slowing with age is driven in part by biology but is significantly affected by the choice to spend time on the couch. Similarly, while some loss in range of motion with age is inevitable, the degree of loss is magnified by sedentarism.
It is fairly simple to break out of the stereotype: We just need to avoid retreating into inactivity with the passing years. The global perception of the aged as doddering and low functioning is less a necessary fact and more a self-fulfilling prophecy when inactivity is added to the mix.
What are the limits of aged performance? How much of our age-related functional decay can be avoided? No one knows, but we should endeavor to find out, not necessarily as part of scientific inquiry but as part of our own self-care into antiquity. When we lose physical function, we become dependent. The longer we maintain our physical fitness, the longer we remain independent.
While not a panacea for illness and injury, exercise—exercise that starts with the smallest of steps and progresses to a robust retention of strength, endurance and mobility—can push the onset of dependency back toward the absolute end of life. A current retiree, a soon-to-be-retiree, and those who will at some point retire will greatly enhance quality of life by becoming physically active and then moving on to progressive exercise.
From one aging individual to another, fight the stereotype. Fight it by choosing to be active and avoiding a self-induced functional deficit that only grows and becomes more profound with the passing years. Choosing the couch has long-lasting ramifications on our independence.
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About the Author: Professor Lon Kilgore is a longtime contributor to the CrossFit Journal and the fitness industry in general. He might be best known for his work with Mark Rippetoe as concept originator, co-author, illustrator, and book designer for “Starting Strength” and “Practical Programming” (first and second editions). He also co-created the Basic Barbell Training and Exercise Science specialty seminars offered through CrossFit in the mid-2000s. After a 20-year professorial career in higher academia, he currently creates and delivers vocational-education courses through the Kilgore Academy and works as a writer and illustrator.
Cover image: iStockphoto.com/Ljupco