Posture, Kinematics, and the Adductor Magnus Muscle in Hamstring Function

Today’s episode features András Hegyi, a final-stage Ph.D. student working at the Neuromuscular Research Center at the University of Jyväskylä in Finland.  His Ph.D. work focuses on regional and inter-muscular hamstrings EMG activity in different hamstring exercises and in running. Hegyi's recently published thesis can be found at University of Jyväskylä. Hegyi is interested in improving biomechanical methodologies to assess hamstrings to further understand hamstring muscle function and injury mechanisms. We’ve done some great episodes on hamstring injury prevention in the past, such as episode 161 with Jake Schuster and 158 with JB Morin.  This show is another fantastic addition to that series as András is a wealth of knowledge on the topic, being well versed on what the research yields in regards to many aspects of training and hamstring development, as well as what is functionally asked of the hamstrings in sprinting and sport. When it comes to hamstrings and injury prevention, a common question is: “What exercises should I do in the gym to help this process”?  An important aspect of the gym and sprinting is that the way these elements “hit the hamstrings” is quite different.  It is important to know what we can, and can’t do in the weightroom to create robust athletes. In this episode, András goes into hamstring strain mechanisms, Nordic hamstrings and variations, different gym exercises that hit different aspects of the hamstring musculature, sprinting and it’s role in injury prevention.  He also shares his thoughts on training the adductor magnus as a synergist of the hamstring.  Another important point covered is the importance of individual muscle activation differences in sprinting versus what we see in the gym, which has big implications on how we are training and assessing athletes. Today’s episode is brought to you by SimpliFaster, supplier of high-end athletic development tools, such as the Freelap timing system, kBox, Sprint 1080, and more. View more podcast episodes at the podcast homepage. Key Points András’ background as an athlete and researcher Primary reasons for a hamstring strains from a physiological and biomechanical perspective Dynamics of isometric exercises and muscle-tendon activity Thoughts on if a Nordic hamstring is actually an eccentric exercise Nordic hamstring training and rotational elements of the hamstring The diver and glider exercises for hamstring health How doing a Nordic hamstring with flexed versus extended hips changes the training effect of the movement Anterior pelvic tilt and effect on the hamstring during a Nordic hamstring The role of sprinting in injury prevention Training for the adductor magnus and it’s role in hip extension and hamstring injury prevention   “The magnitude of fiber stretch is a good predictor of strain injury” “When we stretch a muscle to failure, highly activated muscle absorbs more energy than passive muscle” “The hamstrings must absorb a lot of energy in the late swing phase of running” “The muscle cannot tolerate the same amount of stretch when it is fatigued” “Increased hamstrings activity decreases the magnitude of fiber stretch in the late swing phase” “A big anterior pelvic tilt stretches the (hamstring more) and it typically increases with fatigue” “(In a Nordic hamstring) there is actually a shortening behavior of the fascicles first, then there it’s kind of isometric, and the eccentric only happens at the peak knee flexion torque” “Eccentrics help you to absorb more energy in the late swing phase of running” “When the hips were flexed to 90 degrees, then we reached much higher knee flexion torque; but interestingly the hamstrings activation was much lower, and what this means is that we have more inhibition in the hamstrings and the passive force was higher.  With flexed hips, we have more of an eccentric component,