Running is a high impact sport which puts our lower body joints, bones, and soft tissues under severe stress. In spite of that, some people habitually run. Going for a long run seems to be the physical activity of choice for some people, something they enjoy the most! So then, what is it in our internal mechanism that allows us to run without compromising on our musculoskeletal health? Are we built to run at all?
If we look deeper, we will know that there are many features in the human body, evolved over the past 2 million years, which give it sustained long distance running capacity. It is believed that these adaptations were a requirement for endurance and speed in exploring and hunting.
The Trans Europe Foot race is a multi-day ultramarathon which covers about 4500 kilometers. It tests runners and running to its limits, and provides researchers an ideal opportunity to evaluate the effect of long distance running on the human body.
In studies performed, researchers followed the runners with their mobile MRI vehicle and did scans on athletes every few days. The scans showed degradation in cartilages of knee and lower joints for the first 2000 kilometers. With exception to the patellar joint, nearly all cartilage segments of knee, ankle, and the hind-foot joints showed a significant degradation within the first 1,500 to 2,500 kilometers of the race.
“Interestingly, further testing indicated that ankle and foot cartilage have the ability to regenerate under ongoing endurance running,” Dr. Schütz, leader of the research team, said. “The ability of cartilage to recover in the presence of loading impact has not been previously shown in humans. In general, we found no distance limit in running for the human joint cartilage in the lower extremities.” (http://press.rsna.org/…/me…/pr2015/schuetz/mp4/schuetz_6.mp4)
Several adaptations give humans the ability to outrun every other animal on the planet in endurance running!
- One structural feature of the human body which allows it endurance running capability, is the long spring-like tendon, called Achilles tendon that attaches short muscle fibers to leg and foot bones, basically connecting the calf muscles to the heel bone.
- Another unique feature is the existence of foot arches which act like springs during running.
- Long legs, small foot size, and slow twitch fibers in our leg muscles are some other evolutionary mechanisms that provide structural support to a running-oriented body frame.
- Sweat glands which let us cool down without having to pant, allow us to run longer without the body heat building up.
- Large swivel hips which do not do much while walking, actually help in smooth transition between strides during running. In fact our shoulders and hips are uniquely positioned on our body to aid smooth running.
High from Running
Distance running produces a short term feeling of euphoria, associated with feelings of profound contentment, elation, and well-being. Such a feeling is called a ‘Runner’s High,’ and is caused by a release of ‘Endocannabinoids’, which are lipid-based neurotransmitters responsible for exercise-induced euphoria (among other things.)
While cursorial animals (those that are specifically adapted to running) showed significantly larger amounts of endocannabinoid signaling following high intensity running, same was absent in non-cursorial mammals. This points to the fact that millions of years of evolution has made humans wired to run!
Article Credits – Arunava Chatterjee