The Impact of Curved Track Training on Road Runners: Unveiling Imbalances and Injury Risks

While in Iten, Kenya, known as the Home of Champions, I observed the weekly speed sessions of Kenyan athletes on the Kipchoge track in Eldoret. These sessions typically involve a warm-up run towards the track after disembarking from local taxis about 2km away.

Once gathered on the track, the athletes would commence their speed session, which typically included intervals ranging from 200m to longer 3000m runs. Notably, all runs were conducted in the same direction, following an anti-clockwise route around the track.

Athletic track specifics

Let’s delve into the specifics of a standard athletic track constructed according to the IAAF’s standard dimensions. For the purpose of this discussion, we’ll focus on lane 1, which is where most athletes run during their speed sessions. Lane 1 measures exactly 400m in length, with two straight sections of 84.39m each. The remainder of the lane consists of curves with a radius of 36.50 meters. Consequently, athletes run in a straight line for 168m of each lap and for the remaining 230m, they run while curving to the left. This implies that only 42% of the speed session is executed in a straight line, while the remaining 58% is performed at an angle.

Consequently, approximately 58% of the speed training for these road runners involves running at an angle to the left. This repetitive movement pattern ingrains a connection between fast running and rotation towards the left in the brain. Now, let’s explore the differential muscle function between running straight forward and running on a curve to the left.

Curve running and muscle function

To understand the difference in muscle function between running straight forward and running on a leftward curve, let’s perform a simple exercise. Stand with your left leg in front and your right foot positioned behind, leaning slightly forward as if frozen in the running phase. Your right arm will be extended forward, while your left arm remains behind. Notice how both your feet, pelvis, and shoulders face forward in this stance.

Now, while maintaining this position, rotate your body to the left as if running along a leftward curve. Observe how your pelvis and shoulders rotate towards the left. If you look down at your left foot, you will notice it facing inward in relation to your pelvis and shoulders, while your right foot faces outward. In this position, the internal rotators of the left hip, such as the TFL (Tensor Fasciae Lata) and Gluteus Medius and Minimus, are contracted, while the external rotators, including the Gluteus Maximus and Biceps Femoris (a large hamstring muscle), are elongated. Consequently, during the weight-bearing phase with the left leg, the leg is twisted, causing elongation and disablement of the Gluteus Maximus and Biceps Femoris on a spiral plane.

Now, switch your stance with the right leg forward and repeat the rotation to the left. You will notice that your right foot and leg rotate outward. In this case, the opposite occurs: the Gluteus Maximus and Biceps Femoris are shortened, while the TFL and Gluteus Medius and Minimus are lengthened.

Furthermore, observe the movement of your arms as you pretend to run around the curve. Your right arm moves forward more forcefully and extends further, while your left arm moves backward with greater intensity. Consequently, there is a significant drop of the left shoulder while navigating the curve. All these rotations indicate a notable imbalance, especially when the body is subjected to high-intensity and frequent work in these patterns.

The autonomic nervous system and fascia protection

During high-intensity activities, the autonomic nervous system remains vigilant in protecting the body from harm. When the body assumes a position that may be perceived as dangerous, the brain utilizes immobilization of the fascia as a protective measure. If an athlete exerts excessive effort in these unconventional patterns, the brain will lock the fascia in the leftward rotation position to support the body. This creates a state where the muscles are held in a shortened but “functional” position, facilitating easier coping for the body.

This scenario might be acceptable for track athletes whose running primarily occurs on curves. However, for road runners who predominantly run in straight lines and occasionally navigate curves in both directions, this imbalance may start to manifest, particularly during fast straight-line or left-curve runs. With certain muscles trapped in an elongated position, unable to adequately shorten, chronic injuries can easily arise.

During my time at the track in Kenya, I recorded numerous videos of runners sprinting on the short straight section during their speed sessions. Surprisingly, more than half of these runners exhibited left rotation, even though they were running straight ahead. The brain had already established an association between speed and rotation. These athletes are at risk. How often have you witnessed an elite athlete, in the final 5km of a marathon when sudden bursts of speed are required, drop their left shoulder, followed by a visible decline in performance due to a minor injury? A body stuck in a rotational pattern is a body seeking trouble.

Regrettably, it would be far more beneficial for roadrunners to conduct all their speed training in a straight line. Identifying a straight road and marking off sections for interval training is not a challenging task. By adopting this approach, many chronic injuries could be avoided.

Let us do a few simple tests and see if you are at risk?

Do the following basic tests to determine if your body is already locked in rotation towards the left. You can use a digital goniometer app on your phone to do the exact measurements. They are mostly free to download and is a lot of fun.

Test 1 – Testing for the range of movement of the hip internal rotators

Lie in the prone position. Ask a friend to hold your left hip in position by pushing downwards on the left buttock. Bend the left knee and then allow the leg to drop inwards. The normal range of movement is 45°. Measure the range for the left and the right leg and compare.

Test 2 – Testing for the range of movement of the hip external rotators

Lie in the supine position. Bend your hip and knee to 90° and then ask a friend to rotate the foot outwards. Normal range for this movement is 30°. Measure the range for the left and the right leg and compare.

Test 3 – Testing for shoulder mobility.

You are locked in rotation to the left if you are tighter when doing this test with your left hand at the top and right hand at the bottom as shown in the picture.

If any of these tests show shortening, your body is already locked in rotation towards the left. You need fascia release to restore your mobility and you should not be doing your speedwork on the track.

Trauma and bad habits cause injuries

When we conduct full-body assessments on athletes dealing with chronic recurring injuries or those who have hit a performance plateau, we consistently find that the root causes can be traced back to unresolved emotional or physical trauma, as well as detrimental habits.

Releasing old trauma isn’t overly difficult, but it’s the persistence of these bad habits that keeps feeding the injury and makes it challenging for therapists to restore balance and alignment.

During my time in Kenya, I made a conscious decision to intervene and prevent at least half of the athletes I worked with from training on the track. Many of them exhibited signs of a locked shoulder or hip, which are directly linked to running the curve to the left. One common issue resulting from this running pattern is a left hamstring injury—a familiar sight when top runners clutch their left thigh as they transition from the curve to the straight section.

Ignoring the cause-and-effect relationship can trap you in a cycle of chronic injury indefinitely.