Special to Colorado Track XC by Richey Hansen
Cross Country is a sport for varied surfaces. It isn't supposed to be a track meet, nor is it a road race. Hills, tight turns, water crossings, and even hay bales can factor into the equation. But, the extent to which those obstacles are incorporated and where they are introduced, on a course can pose an inherent risk that must be considered. This is especially true when the competitors are high school athletes still progressing through various stages of development.
The current state cross country course at Norris Penrose Equestrian Center presents a few of these obstacles that, it can be argued, are fundamentally consistent with the spirit of cross country. There are steep uphills, a long downhill, two creek crossings, and a bottlenecked portion of the course. The course is meant to be challenging, but is it an appropriate competition forum for adolescent-aged individuals?
Not surprisingly, there have been many concerns expressed over the current layout of the state course.
I understand the logistical issues associated with the timing of the bottleneck for the first creek crossing and how challenging it may be to ascend Little and Big Willis after the first mile point. But the aspect that had me most concerned as a coach and that worries me as a practitioner, is the length and grade of the downhill section of the course.
From the top of Big Willis to the second creek crossing, it is a net downhill of 158 feet over 1.25 miles. The concern with this is the increase in force absorbed when fatigued. Running downhill puts an increased responsibility on the eccentric control of our stabilizers to dissipate force with each stride. Meaning, you need proper control of your foot, shin, and hip muscles when running fast downhill to make sure you can evenly distribute the force that is being absorbed. Otherwise, you risk putting an inordinate amount of impact stress on your bones, tendinous attachments, and joint cartilage. Below are a few injuries that have an increased risk of being sustained due to the profile of the current state course.
One spectrum of injuries more likely to occur in this setting would be shin splints/stress reactions/stress fractures. Stress fractures occur when the loading rate at the bone exceeds what the bone can withstand. Bones (in particular the tibia, metatarsals, and femoral neck) are susceptible to tensile loading stress during running, which can be increased when there is fatigue of the supporting muscle stabilizer system.
For instance, your shin is most likely to bend on impact in the posterior medial direction during ground contact. This can make the area of bone that is thinnest (typically in the center of that bend) the least likely spot to be able to withstand excessive tensile loads. When the calves are in a fatigued state (e.g., after running up a long hill), the tibia then has to absorb more of the force placed on it without having the supporting muscles help dissipate that force. Posterior shin splints, stress reactions, and stress fractures are the end result of this mechanism, with all three varying in intensity along the same spectrum. This same tensile loading concept can additionally be applied to the metatarsals and the femur.
(diagram courtesy of Popp, et. al)
What we see with the state course is a combination of factors that can individually increase excessive bending loads on the bones and shearing forces on the joints due to a hampered or abnormal loading response:
• Adolescent runners -- many of whom are inexperienced distance runners who have made drastic increases in their running volume preparing for their first cross country season, and who haven't yet developed efficient strength or recruitment of the muscle stabilizers
• Running at speeds that are faster than their anaerobic thresholds -- this can lead to metabolic fatigue leaving the bone more susceptible to injury
• A significant rate of decline (10% grade over a stretch in excess of 400 feet) -- which increases the amount of impact force required to be absorbed
• Significant inclines (Little and Big Willis) preceding the stretch of decline -- this causes additional metabolic fatigue, especially in the calf and hip muscles which would otherwise help to protect the tibia and femur from loading forces
In addition to bone stress injuries, other injuries with an increased risk include IT Band syndrome and hip labral tears. As the hip stabilizers fatigue (from the long uphill to long downhill transition), it becomes harder for the hip and knee to efficiently absorb the increasing impact forces. This causes a mechanical shift toward more internal rotation at the hip and an increase in valgus knee angle. This means that the hip is more likely to turn inward and cause the knee to dip across the body because the muscles resisting excessive motion in that direction are tired.
With the IT Band, this mechanical breakdown causes an overstretching of the muscles on the outside of the hip causing increased tension through the band. This then leads to compression and irritation of the bursa (a fluid filled sac on the outside of the knee) where the IT band attaches.
Additionally, the hip labrum, cartilage along the pelvis where the femoral head sits, and muscles surrounding the hip are placed under increased shearing and tension forces due to the higher impact forces. As the hip stabilizers fatigue, it is less likely for them to equally dissipate force across the joint surface.
When running on significant declines, the tissues on the front of the hip experience increased tension stress. This can lead to excessive tissue stretch due to longer stride length and more shearing force (uneven sliding between two surfaces moving in opposite directions) placed along the cartilage. Similar to bone, when the load exceeds what the tissue can tolerate, damage will occur. This can lead to tearing of the labrum, strain of the hip flexor or quad, and irritation of the hip bursa.
This is not to say that everyone who runs on the Norris Penrose course will get hurt. But, the risk of injury is much higher on a course with the current layout than it would be on a course with a more varied profile (e.g., shorter rolling hills across multiple surfaces such as grass, dirt, and crushed gravel).
One of the central ethical precepts in medical practice is "primum non nocere" meaning "first, do no harm". Meaning the doctor has to decide if the risk of the treatment outweighs the potential health benefit. Should we not follow the same principles as coaches and administrators when deciding what competitive environment we should be placing adolescent athletes in?
When I was coaching at Peak to Peak, I would assign races for athletes during the season based on how their body was feeling and what the course profile entailed. For example, if an athlete was dealing with a shin or IT band issue, they weren't running Liberty Bell during the season (asphalt and aggregate trail over a net downhill).
The goal was to optimize our ability to keep everyone training and have everyone relatively healthy for the state meet. The tough part comes when the aspects of the state course pose the very risks you are trying to have your athletes avoid. I understand it's cross country, where undulating terrain, obstacles, and course strategy come in to play. But, a long uphill immediately followed by an even longer downhill that together make up about half of the course is a concerning feature to force developmental age athletes to compete over.
Ask yourself how many of your athletes were suffering with "shin splints" prior to the state meet. Then imagine how painful it must have been to run an extended uphill then downhill fast on that injured shin. And that is only one family of injuries that can be initiated, or aggravated, on a course configuration such as we have with the state meet.
Dr. Richey Hansen conducts his practice under the business name of High Altitude Spine and Sport. You will find a wealth of additional running-related information at his website.