Toward a Universal Ethic of Human Movement (Part 1)

As I stated previously, ethics consists of the set of precepts concerned with what an individual human being should do. Yet ethical theory is scalable; different ethical standards exist for different individuals based on variations in age, circumstance, and mental and physical capabilities. One may consider a pauper generous even though he gives what would be a pittance for a rich man, or a trained soldier a coward if he flees from a battle that would justifiably frighten a child. Even killing another human warrants different consequences for young children, mentally challenged persons and fully cognizant individuals. Though we can say a child should not kill another human being, we struggle to convey the force of that sentiment to someone too young to grasp the difference between right and wrong.

Recall Aristotle’s definition of virtue: “having [the right] feelings at the right times, about the right things, toward the right people, for the right end, and in the right way.”1 Virtue is subject to a variety of conditions. It is “not the same for all,”2 but relative to each individual and her particular situation. Virtue requires correct reasoning about which situations call for a particular virtue and what action is required, and then acting with the appropriate virtue in those situations. Yet different situations call for different virtues from different individuals under different circumstances. What one individual should do in a given situation may contrast with what another individual should do.

In my essay The Ethics of Human Movement, I stated “a healthy adult between the ages of twenty and thirty-five is certainly capable of lifting his or own body weight,” a condition I applied loosely to the subsequent precepts of human movement:

  1. A human being should be able to lift his or her own body weight off the ground.
  2. A human being should be able to maintain a comfortable resting squat position for at least ten minutes.
  3. A human being should be able to travel 5000 meters (3.11 miles) in thirty-six minutes.

But what about humans with injuries, physical disabilities, or those who fall outside the age range of twenty to thirty-five? I do not expect a child or a grandmother to be as strong or fast as an adult in his physical prime. These precepts must be scaled to accommodate the variety of uncontrollable circumstances which affect individual human beings. I begin here with age since this phenomenon touches all humans and is responsible for many of the peaks and declines in individuals’ mental and physical capabilities. One way to scale these precepts of movement would be to use actual results by age from athletic competitions. This standard allows us to set criteria based on exemplars of physical virtue. It considers what is actually possible, in contrast to the abilities of the average person. Since we are examining ethics, or the standards which human beings should achieve, it makes sense to look at optimal achievement rather than mediocre, unrealized capacities. Virtue is an exemplar, not the least common denominator. But lest the following start to look too much like the benchmarks for a junior high fitness test, I will say that things really get interesting when we turn the question of scalability back onto social ethics to examine the values humans hold with respect to one another.

To begin, consider Tables 1 and 2, which express the U.S.A. Powerlifting deadlift records for men and woman in various age groups as a ratio of weight lifted to the lifter’s bodyweight.

Toward a Universal Ethic of Human Movement (Part 1)

In both men and women, strength peaks between ages twenty-four and thirty-nine, with the values in the third column of each table indicating the ratio of pound for pound strength for each age group in comparison to the twenty-four to thirty-nine age group. Thus, if top powerlifters lift 100% of their capacity between the ages of twenty-four and thirty-nine, they lift about 90% to 95% of their maximum capacity at twenty to twenty-three years old and 83% to 90% maximum capacity at forty to forty-four.

This data provides a guideline from which to extrapolate estimates for how much weight any adult human should be capable of lifting at a certain age. Since our ethical precepts for human movement offer minimum capacities, we take the smaller of the two gender values for each age group to produce Table 3, which reflects the amount of weight a human being should be able to lift off the ground relative to his or her own bodyweight over a range of ages.

Toward a Universal Ethic of Human Movement (Part 1)
*-Strength capacities after age 60 seem to level off around 40%, with the exception of a few outliers. The age ranges from 60 to 94 in Tables 1 and 2 are therefore compressed to 60+ in Table 3.

Moving to the second ethical precept for human movement, a full squat requires suitable range of motion in knee flexion (bending the knee) hip flexion (bringing the knee toward the chest), hip abduction (moving the leg away from the body’s center line), hip external rotation (turning the leg outward from the hip) and ankle dorsiflexion (bringing the top of the foot toward the shin). Table 4 lists average hip and knee range of motion by age, gender and race among 1,683 subjects. All values are measured in degrees and reflect an active range of motion, i.e. range of motion created by the individual’s own muscular activity without any application of external force.

Toward a Universal Ethic of Human Movement (Part 1)

This data supports other research indicating flexibility generally decreases from early childhood until puberty, increases throughout adolescence, levels off in adulthood and eventually decreases with age.Yet adults who remain active can minimize flexibility loss, and as Table 4 indicates, even when the activity level is not controlled, flexibility losses with age are relatively minimal.

Toward a Universal Ethic of Human Movement (Part 1)
Exemplars of human movement [7]
Though a full squat requires more range of motion than the values in Table 4, squatting puts joints through a passive range of motion. The weight of the body in a squat acts as an external force on the joints and produces a greater range of motion than the active range an individual can achieve with her own muscular strength. If a healthy adult should be capable of maintaining a full squat for ten minutes or more, this range of motion should not decrease significantly with age, especially if the individual remains active. In countries where individuals regularly squat, people maintain this ability even into old age, as evidenced by the image on the left. Given the aforementioned declines in strength with age, muscular endurance might seem the greatest limiting factor in maintaining a full squat for an extended period of time. However, a full squat is a resting position; further descent into the squat is limited mainly by the joint range of motion and contact between body parts, and less so by muscular strength (as in an isometric wall sit). Assuming the individual can achieve the requisite position, significant strength should not be required to maintain a full squat. Still, in order to account for joint wear, slight decreases in flexibility that may limit the attainment of the comfortable position and other age-related complications, I propose the following standards for range of motion.

Toward a Universal Ethic of Human Movement (Part 1)

Admittedly, research in the capacity of individuals of different ages to achieve a full resting squat position is limited. The standards in Table 5 are based on estimates derived from limited data of isolated joint movements. Further data is required to set more appropriate guidelines for this movement standard.

Continue reading Toward a Universal Ethic of Human Movement in Part 2.


  1. Aristotle. “The Nature of Virtue.” Ethical Theory, Ed. Russ Shafer-Landau, Malden, MA: Blackwell Publishing, 2007, p. 678.
  2. Ibid, p. 677.
  3. Values derived from “Men’s American Records.” U.S.A. Powerlifting. 13 July 2013. Online. 22 Sep. 2013. 2cf819ab-1d0c-4a59-adef-b997869bcd8d.
  4. Values derived from “Men’s American Records.” U.S.A. Powerlifting. 27 July 2013. Online. 22 Sep. 2013. 83016a42-d021-475b-9bb5-b0e69a9da000.
  5. Roach, Kathryn E. and Miles, Toni P. “Normal Hip and Knee Active Range of Motion: The Relationship to Age.” Physical Therapy, 1991, p. 656-665. Online. 23 Sep. 2013.
  6. Alter, Michael J. Sport Stretch. Champaign, IL: Human Kinetics, 1990. p. 20.
  7. “Asian squat.” Stretch to Win ® Institute. Image. 21 May 2011. Online. 30 Sep. 2013.