Strength and Longevity
By: Barbell Logic Team
There is a popular facet of exercise research that has to do with predictors of longevity. People want to know if they are at risk for life-threatening conditions or the precipitous decline that often precedes terminal aging- or health-related developments. And they want to know what achievable results they might be able to pursue to make them less at risk. To that end, researchers have developed several fitness tests attempted to show some connection between relatively simple tasks performed and all-cause mortality. Below we take a closer look at some of these popular at-home Am-I-Going-to-Die-Soon tests and how they might relate to things you can do in the gym.
Strength and Longevity (Tests)
There is a popular facet of exercise research that has to do with predictors of longevity.
Longevity in these cases means the relationship between the test and your likelihood to encounter all-cause mortality in a specified time. All-cause mortality is precisely that: death from all causes. It is a term often used in research papers that want to examine a variable and its relationship to non-specific causes of death. There is a health-related aspect to all-cause mortality as healthy people are less likely to develop terminal syndromes at younger ages than their less-healthy counterparts—syndromes like those that form Dr. Sullivan’s Sick Aging Phenotype, metabolic syndrome, systemic inflammation, sarcopenia, osteopenia, frailty, polypharmacy.
There is also a presumed functional component to all-cause mortality. People are living longer now than ever before in human history. One of the concerns of aging adults is their functionality into old age. Presumably, if there were a physical measure that could predict all-cause mortality, it might relate to the inevitable physical decline of aging. While this is a presumed connection, it is a powerful one. Fear of dying young may be a preoccupation for many middle-aged people and seniors, but existing in a state of complete dependence can’t be far behind on the fear factor scale.
People want to know if they are at risk for life-threatening conditions or the precipitous decline that often precedes terminal aging- or health-related developments. And they want to know what achievable results they might be able to pursue to make them less at risk. To that end, researchers have developed several fitness tests attempted to show some connection between relatively simple tasks performed and all-cause mortality. They are popular as a kind of longevity guessing game you can play with yourself. The nice thing about these tests is that if you fail, you can do something about it. The tests themselves, and certainly the way they are popularly portrayed in the media, do not tell you “how” to improve or even why the test might be (or might not be) useful. So, let’s take a look at some of the popular at-home Am-I-Going-to-Die-Soon tests and how they might relate to things you can do in the gym.
The Sitting-Rising Test (SRT)
The Sitting-Rising Test is an attempt to incorporate a lot of primary fitness markers into two functional outcomes: The ability to sit on the floor and the ability to get up from sitting on the floor. Along with cardiorespiratory fitness, “Body composition, muscle strength and power, flexibility, and postural stability are…relevant for proper health and function” and together may provide a comprehensive assessment for functionality and, therefore, all-cause mortality. (de Brito, Ricardo, de Arau´jo, Ramos, Myers, and de Arau´jo, “Ability to sit and rise from the floor as a predictor of all-cause mortality,” European Journal of Preventive Cardiology, 0(00) (2012).)
For the SRT, a person stands barefoot on a flat surface. A doctor or evaluator instructs the person, “Without worrying about the speed of your movement, try to sit and then to rise from the floor, using the minimum support that you believe is needed.” Your ability to sit and rise can each earn you a maximum of five points. You lose points for using supports: If you place a hand or forearm on the floor or your knee, you lose a point. Same if you use a knee on the ground or the side of your leg as supports. The evaluator can also deduct half-points for losses of balance or unsteady movement. (The authors of the above study have a video explaining the SRT evaluation process, you can watch it here.)
The theory of the SRT is that a low score on the test reveals a person’s more-difficult-to-measure low levels of strength and cardiorespiratory fitness. The logic of this comes from a presumption that people with lower strength and cardiorespiratory fitness are more likely to die from nonspecific causes than people with higher levels of fitness. One often-cited study showed an association between a low SRT score and a “>6-fold higher all-cause mortality in men and women.” We are not commenting on the data itself, but the study does a good job of acknowledging its limitations and mostly holds the SRTs value in “screening, functionally classifying, and risk stratifying large samples of subjects.” (Id.) The test is easy to perform, requiring little space and no special equipment.
The Push-up Test
Earlier this year, there was some popularity surrounding the findings of one study that seemed to link cardiovascular health to your ability to perform push-ups. This study aimed was to test an “office-based objective measurement that clinicians can use to assess the association between fitness and cardiovascular disease risk.” This study collected data from ten years of physical exams and medical records of male firefighters in Indiana, each of whom had a baseline and periodic fitness tests that included their ability to do push-ups:
“For push-ups, the firefighter was instructed to begin push-ups in time with a metronome set at 80 beats per minute. Clinic staff counted the number of push-ups completed until the participant reached 80, missed 3 or more beats of the metronome, or stopped owing to exhaustion or other symptoms (dizziness, lightheadedness, chest pain, or shortness of breath).” (Yang, Christophi, Farioli, et al., “Association Between Push-up Exercise Capacity and Future Cardiovascular Events Among Active Adult Men,” JAMA Netw Open, 2(2):e188341 (2019).)
The study then compared baseline push-up tests against incidents of cardiovascular disease among the firefighters over ten years.
Men in the cohort who performed 10 or fewer push-ups were statistically more likely to have cardiovascular events. According to the authors, “The findings suggest that higher baseline push-up capacity is associated with a lower incidence of CVD events. Although larger studies in more diverse cohorts are needed, push-up capacity may be a simple, no-cost measure to estimate functional status.” They also found, however, that the same statistics did not hold for men who could do 31-40 push-ups who had higher rates of CVD than those who could do 21-30. Like the SRT test, there’s more to fitness than you can measure with a simple performance test like this one.
The Muscle Power Test
This test expands on the SRT test. The SRT’s validity rests on the premise that simple, functional assessments incorporate things like cardiorespiratory fitness and strength. The researchers decided to test “Muscle Power” using an upright row as a predictor of all-cause mortality. Taking the basic functional test and replacing it with more direct measurements of “muscle power.”
This study concluded that muscular power (differentiated from basic strength measures) above the median for men or women, correlated with a lower likelihood of premature death in the six years following the study for a 3878 “non-athlete adults aged 41 to 85 years old.” The study’s lead author says, “Rising from a chair in old age and kicking a ball depend more on muscle power than muscle strength, yet most weight-bearing exercise focuses on the latter. . . . Our study shows for the first time that people with more muscle power tend to live longer.” (Public release, “Ability to lift weights quickly can mean a longer life,” European Society of Cardiology (April 2019).)
While we could comment on the methods of measuring power using an upright row, the point here is that there is a continued interest in functional testing to show longevity. In this case, the researchers seem to presuppose the value of power over strength for functionality. Or, perhaps following their findings, they decided that because they found a correlation, the functionality of power must be greater than strength alone. Unfortunately, they didn’t test the participants’ base strength levels as a control, which might have given more insight into what mechanism gets you from displaying power to functional fitness and a reduced risk of all-cause mortality.
The authors presented this study to the European Society of Cardiology. You can read the public release from the European Society of Cardiology and find the authors’ abstract here. Interestingly, the authors suggest ways of “training to increase your muscle power”:
- Choose multiple exercises for the upper and lower body
- Choose a weight with the load to achieve the maximal power (not so easy to lift and not so heavy that you can barely lift it)
- Do one to three sets of six to eight repetitions moving the weight as fast as possible while you contract your muscles (slow or natural speed in returning to initial position)
- Rest for 20 seconds between each set to sufficiently replenish the energy stores in your muscles to start the new set
- Repeat the above for the other exercises (biceps curl, etc.)
Also, how to make progress:
- Start with six repetitions in each set and when the exercise becomes easy, try to increase to eight
- If it becomes easy again, increase the weight and go back to six repetitions
- If you are unable to complete the repetitions with the proper technique, avoid “cheating” and go back to fewer repetitions or less weight. This is important to prevent injuries.
(Id.) The outline of advice shown here and in many of these other types of health and fitness tests show a lack of understanding of training in general for physical improvement, regardless of the statistical validity of the studies’ findings. While the studies might show a correlation between the sitting and rising, your ability to do push-ups, and the performance of a lift, it is reaching for the researchers to then conclude that becoming more flexible or improve your muscular endurance for a specific task, or improve your power production improves your longevity. This assumption is still reasonable given the basic premise of these studies (that improved functionality leads to less all-cause mortality), but that premise itself stands with or without these studies.
The authors go from reaching to a leap of conceit, however, when they also give out training advice based on their studies. The path of efficient, effective physical improvement comes from more fundamental principles than those comprised in an outcome-determinative functional test. So, below let’s consider each of these tests, what they measure and how you can improve your functionality in way that would translate to each of them without limiting yourself to the test itself (i.e., how you get more functional while also improving your ability to sit and stand, do push-ups, and produce power?)
Hint: It Pretty Much Starts With Strength
If we generalize the functional aspect of each of these tests, we can examine the adaptations they might represent and discuss how those adaptations relate to training. A principle of adaptation is that stress drives physical change. Any functional test is measuring some aspect of a person’s physical competence, aspects that can be changed through training, applying the concepts of stress-recovery-adaptation. Outcome-based observations—how well you can sit or stand, how many push-ups you can perform, or how much power you can produce—are simply measurements of some more basic physical capacity.
Balance and Body Control
Each of the tests above test different physical adaptations. The sitting-rising test measures a person’s ability to control their body in space: Balance. Balance is a state in which your center of mass stays vertically over your base of support. Your ability to maintain balance is a combination of sensory input, how you process that input (your sensory perception), and muscular output. The test is specifically designed to measure your ability to not fall over; each time you put down a hand or limb for support you are increasing your base of support beyond the minimum amount needed.
Balance is both a trainable skill and related to your muscular control. Keeping your balance comes from the combination of sensory input with your learned experience. As with any skill, balance improves with practice. Also, more skeletal muscle mass means better balance as you age. If you can practice keeping your balance and improve the strength of the muscles that you need to do so, you can improve a functional outcome in a balance test.
Enter the squat. “[B]asic barbell exercises that use lots of muscle mass over a long range of motion while standing on the ground in a balanced position, thereby allowing the use of heavy weights that develop the ability to generate high amounts of force while balancing the load and controlling the position of both the load and the body in space.” (Rippetoe, “Practical Programming for Strength Training” 3d ed.) No lift or movement uses more coordinated muscle mass over as long of a range of motion and with as much loadable capacity as the barbell squat. The squat requires you to control your center of mass at increasingly heavier weights as you lower yourself from standing into a deep squat position with nothing to keep you from falling over but your motor control. Barbell training is a skill that incorporates and improves the skill of balance by increasing the loading, changing your center of mass slightly as you do so and making the whole operation a little bit more difficult every time you lift.
Strength and Muscular Endurance
The push-up test is a test of muscular endurance. Except for the person who can only do a single one, the push-up test is at least partially a test of muscular endurance. Each repetition is a sub-maximal effort, repeatable but for the build-up of muscular fatigue. Though we tend to separate muscular endurance from strength training, we really shouldn’t.
Consider what is necessary for someone who can do only one push-up to change that maximal effort into one of muscular endurance. If that person doubled the amount of force he could generate against the floor, then what was once a maximal effort event is not a 50% effort event. At 100% effort, the limiter was purely force production, but at 50% he will be limited by fatigue. Strength affects muscular endurance by reducing the amount of force necessary for each submaximal contraction, relative to the individual’s maximal strength.
Though there would not be a one-to-one relationship between changes in your bench press PR and the number of push-ups you can do, the amount of force you exert doing push-ups is some sub-maximal percentage of your bench press. (Or a sub-maximal expression of your combined bench press and overhead press ability.) While the improvements to your general strength will have diminishing effects the more push-ups you can do, those in the high-risk category of the test (<10 push-ups) are still in the realm of the test being an expression of strength.
Strength and Power
The muscular power test was intended to measure your ability to produce force quickly. Muscular power is the amount of force you can produce over time. For a maximum-effort deadlift, you have to produce a lot of force, but the lift happens slowly. We can calculate the amount of work done on the barbell as the amount of force applied to the barbell times the distance it travels, from the time the plates leave the floor to the lockout position. In a true one-rep maximum event, the amount of force used to move the barbell will be very similar to the bar’s gravitational potential energy (how much it weighs). So, work is primarily a measure of force production and the range of motion of the lift. But what if the weight on the bar is light and you move it quickly? If we take the amount of work performed and divide it by the amount of time it took to move the barbell from the ground to the lockout position, then we have measured the amount of power displayed in the lift.
In comparison to our 1RM deadlift attempt, a successful power clean will move through the same range of motion much more quickly. The power clean is not pulled with a constant force. Instead, it will continue to accelerate through the first pull (which has a similar range of motion as the deadlift). This change in velocity means that a relatively light clean (compared to your deadlift) can have a significantly higher net impulse that carries it to the rack position.
If we accept the assumption that greater potential to produce power leads to better longevity outcomes, then we must answer the question of how do we improve our ability to demonstrate muscular power. The study authors above suggest you “choose a weight for maximum power.” That’s much easier said than done when you do not train in a lab while standing on a force plate. There is also no time component for their recommendations. Presumably, they would prefer exercises like the power clean (or upright row) over the “slow lifts” like heavy squats and deadlifts. But they are leaving out half of the power equation.
Power is force times distance over time. For a given range of motion, you can demonstrate more power by either producing more force or moving the weight more quickly. The problem with moving weights quickly is that there is an important neuro-muscular component to this. How quickly you recruit muscle fibers to produce maximum force varies from person to person, and this efficiency is not really trainable. Either you are explosive, or you aren’t.
But we are really adept at improving our ability to produce force. You improve your mechanical force by increasing the number of contractile fibers in your muscle tissue through basic strength training. Think about it this way. Who has a bigger potential power clean: the person with the 225# deadlift or the person with a 405# deadlift? The authors of the muscular power study seem to conflate the ability to demonstrate power with an actual demonstration. These are not the same thing. Training for strength will improve your ability to produce force and therefore power without having to mimic the exercise used in the study.
None of this article is meant to call into question the validity of the studies mentioned or even to argue that strength is the secret fountain of youth and immortality. Instead, we are making the argument for logical training based on a particular goal. We find, time and again, that all physical goals benefit from strength on the most basic levels. Whether your goal is to look good, be more functional, or live longer, if you aren’t strength training you aren’t giving yourself the best foundation for progress.