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When we look at the biomechanics of running in triathletes and marathoners, there are different body loads compared to walking and sprinter (speed) runners, which are a normal activity. We all know external factors (floor, slope, etc.) and material factors such as shoe selection. However, the most important part in running biomechanics is that the knee-hip-pelvis-head-spine-arms are affected as a chain, starting from the contact of the foot with the ground. The reverse is also possible. Any small angle change from top to bottom affects running technique, loads on all joints and running performance. This is also associated with injuries.
The knee flexes 45 degrees in the stance phase of running and extends up to 25 degrees in the pushing phase. In the swing phase, the knee is bent (flexed) 90 degrees in running and 105-130 degrees in sprinting. During the entire movement, the Quadriceps-Hamstring muscles work together by contracting eccentrically and concentrically.
Speed is one of the most important factors affecting running. As the running speed increases, the heel strike decreases, and the area of the foot that touches the ground moves from the back foot to the front foot. Long-distance runners have less speed than sprinters. In long-distance runners, the movement continues in a fluid state with the phase of falling on the midfoot and loading towards the forefoot, pushing from the toe.
As running speed increases, pelvis movement increases, body rotation increases, trunk forward tilt increases, body center of gravity changes, hip bends more, running has more stride length.
On the contrary, long-distance runners have less stride. For long-distance runners, running with the upright position of the trunk does more harm than good. As can be seen in the picture, a landing occurs on the heel in an upright posture. Therefore, the load on the knees, hips, pelvis, spine and shoulders increases, causing injury in various joints due to intermittent (frequent, little) loads. When running with the spine upright, more effort is required to leap forward and performance decreases.
In triathlon athletes, core (abdominal-back) muscles are important in all 3 areas, but they are of primary importance in running. Many scientific studies have shown that core muscle weakness disrupts the whole body biomechanics in running and causes lower extremity injuries. Isolated and combined movements of the lumbo-pelvic muscles, trunk lateral flexors and hip muscles can be achieved with current core exercises. (* current core exercises ??)
We know the effects of core muscles on performance or injury in many sports disciplines. In the article of my master’s thesis, which I am proud to have had published in the Journal of Exercise Therapy and Rehabilitation in March 2020, before the Tokyo 2020 Olympic and Paralympic Games, we proved that strengthening the core muscles or supporting them externally with kinesiotape, elastic corset, increased sport-specific performance and reduced pain.
Of course, strengthening the arm muscles is also very important. Considering the long-distance runners’ performance and oscillations, the arms are static-dynamic, open kinetic and closed in order to prevent arm-shoulder-neck pain after training or a race, to ensure that the arms are kept close to the body, to prevent the arms from swinging (to prevent swinging and causing trunk rotation) must be kinetically strengthened. Again, in this example, there are special exercises other than the classic ones.
As the running speed increases, it is seen that the center of gravity decreases with more pelvic movement and trunk bending forward (flexion), at the same time, there is a wider stride length with more bending (flexion) of the hip.
Activation of the Gluteus medius and Tensor fascia lata muscles is recommended to prevent rotation of the pelvis. Of course, during the recovery phase after training, these muscles, like all body muscles, need to be relaxed and relieved with special techniques. Thus, iliotibial band syndrome can also be prevented.
In order to increase running performance in triathletes and to allow more work with less energy, the body is in a forward inclined position of about 15 degrees, the arms are kept as close to the body as possible, while landing on the midfoot and sweeping the ground while giving the load to the forefoot, taking support from the big toe. Again, it is recommended to perform a pushing phase with a forward leap. In the continuation of the movement, if the knee is bent and the foot approaches the hip in a circular manner, the movement takes place in a fluid manner.
Even though it takes time to make such changes in the running technique, small mistakes can be corrected by getting help from a professional team, using special athlete performance analysis systems or watching the run with video analysis, accompanied by a trainer, and correcting the technique. Therefore, performance is increased and injury protection is provided.
Proprioceptive sensory training and neuro-kinetic exercise in modifications can be made for the correct technique after the analyses.
1-) Kerr B, Beauchamp L, Fisher V, Neil R. Footstrike patterns in distance running. Biomechanical aspects of sport shoes and playing surfaces Calgary, Canada: University Printing. 1983:135-42.
2-) Novacheck TF. The biomechanics of running. Gait & posture. 1998;7(1):77-95.
3-) Scott SH, Winter DA. Internal forces of chronic running injury sites. Medicine and Science in Sports and Exercise. 1990;22(3):357-69.
4-) Fredericson M, Cookingham CL, Chaudhari AM, Dowdell BC, Oestreicher N, Sahrmann SA. Hip abductor weakness in distance runners with iliotibial band syndrome. Clinical Journal of Sport Medicine. 2000;10(3):169-75.