Schuermans J, Van Tiggelen D, Palmans T, Danneels L, Witvrouw E. Deviating running kinematics and hamstring injury susceptibility in male soccer players: Cause or Consequence? Gait & Posture 2017, 57:270-277.
This study looked at the association between running mechanics and hamstring injuries in both a retrospective and prospective design. The authors documented the motions of the pelvis and trunk in addition to the usual lower extremity measurements. The subjects were 30 male soccer players between the ages of 18 and 35 who had a history of hamstring injury during the previous 2 years, but presently had no symptoms. They added 30 matched control subjects without hamstring injury.
The retrospective component of the study involved documenting the running kinematics during a sprint of the previously injured group compared to the injured group. The prospective aspect was to monitor the 30 uninjured players for 1.5 years to see who got injured. Three-dimensional bone segment data was collected during a maximum speed sprint. Data processing occurred following accepted procedures to allow the comparisons. The leg movement was divided to create 3 distinct phases: forward leg swing, stance, and backward leg swing.
The prospective analysis revealed no significant difference in the leg, pelvis, and trunk kinematics between the controls and the previously injured players. Of the 30 control subjects, 29 completed the study. Four of the 29 suffered a hamstring injury during the study period. When the running data from those 4 subjects was compared to the other 25 using a curve analysis procedure, differences were identified. The injured players showed increased anterior tilting of the pelvis throughout all 3 phases, but it became statistically significant during the backswing. The trunk motion of the injured players demonstrated a more laterally bent position during the forward swing, and more trunk motion during the backward swing. Finally the pelvis–thorax coordination was less stable with more fluctuations when compared to the uninjured subjects.
The importance of this article is the evidence that trunk control (or core stability as described by some) is related to hamstring injuries. By inference, it suggests part of the reason that these injuries are often difficult to resolve and commonly recur. If the movement / control of the trunk is a causative factor, then this must be addressed in rehabilitation. It also indicates that training and conditioning programs to prevent hamstring tears and other lower extremity injuries should be designed so that control of the trunk is an integral part of the training movements.
At Gray Institute®, the Principle of 3D drives what we do. Traditional hamstring strengthening exercises where the knee is flexed against resistance are considered “far from function,” and therefore not a choice for training and rehabilitation movements. Flexing the knee against resistance works the hamstring muscles in only 1 plane. These movements are done with the pelvis and trunk either not moving or even stabilized by the exercise apparatus. Anatomy tells us that the hamstring is designed to lengthen and shorten in all 3 planes at the hip as well as the knee.
Functional Muscle Function at Gray Institute® goes beyond the anatomical model. If the hamstrings attach to the pelvis, then they control the pelvis. This means from a Chain Reaction® standpoint, the hamstrings create and control motion of the lumbar spine as well as further up into the thoracic spine. So if the hamstrings influence the thorax, then it should not be surprising that this research study showed that the thorax would influence the hamstring muscles. The human machine is a bi-directional Chain Reaction®.
From a practical standpoint, rehabilitating and training the hamstring muscles for running or any other sport should use the trunk as a driver to lengthen and load the hamstring muscles. Using the Performance System within 3DMAPS® (3D Movement Analysis & Performance System) – specifically, pivots in 3 planes of motion – will produce both top-down and bottom-up drivers for the hamstrings. This type of training prepares the hamstring muscles to decelerate and accelerate motion as part of an integrated system with the other muscles of the lower extremity, trunk, and upper extremities. These movements based on the Principles of Applied Functional Science® are never “far from function!”