Seay JF, Van Emmerik REA, Hamill J. Influence of Low Back Pain Status on Pelvis – Trunk Coordination During Walking and Running. Spine 2011, 36: E3070-E3079.
This article looked at the coordination between kinematic motion of the pelvis and trunk. They investigated this coordination in all three planes during walking and running at different velocities on a treadmill. They were interested to discover if the coordination patterns changed as a result of low back pain (LBP). There were 3 groups: current history of LBP, resolved LBP, and no history of LBP.
To measure the coordination patterns they used a data analysis technique from the dynamical systems approach to studying movement called relative phase. This looks at the relationship between two body parts that are moving together. If the two parts move in the same direction they are considered in-phase, while if they move opposite the coordination is anti-phase. In perfect in-phase coordination the angular relationship is 0 degrees. Perfect anti-phase is 180 degrees. Often the coordination is not perfectly either 0 or 180 degrees. This means that one part would be leading the other.
From a functional movement standpoint, practitioners of Applied Functional Science® (AFS) would be interested in how much motion occurs in each of the three planes in running compared to walking. Also of great interest is the question: Which bone segment is leading the movement in the opposite direction? During walking, the motion of the pelvis is considered the primary driver, with the trunk rotation in the opposite direction (anti-phase) being a biomechanical response to the leg movement. Is this the same for running? Also, what happens when the speed of either walking or running increases?
The primary finding of this research was that both the current LBP group and the resolved LBP group demonstrated a different pattern of coordination compared to the no LBP group. The LBP groups showed more in-phase coordination during part of the walking or running cycle. This occurred in each of the three planes, although statistically the findings are more complex. Biomechanically, this reduces the amount of relative joint motion that occurs in the spinal joints during anti-phase motions, which is consistent with what the authors termed “guarded gait.”
The rest of this blog will focus on the changes in ROM for the control group between walking and running in the transverse plane only. During walking as the speed of walking increased the pelvis rotation increased. Increases in pelvis rotation allow the leg to reach forward thereby increasing stride length. The rotation of the trunk was always less that the pelvis regardless of the walking speed. During running pelvis rotation increased as the speed of running increased (similar to walking), but the overall range of motion was not substantially greater. The big change in running occurs in the trunk rotation in the transverse plane. The amount of trunk rotation increased approximately 200% at the higher running speeds.
The major increase in transverse plane trunk motion during running raises another question about coordination: How important is the trunk as a primary driver of running? The results of this study, combined with other research, force us to look at which motion (trunk or pelvis) reverses first if they are not perfectly anti-phase. Some results indicate that the trunk motion reverses first. This suggests the importance of the trunk in activating muscles and generating forces required to run efficiently. Should training for improved running performance emphasize trunk rotation to increase speed?
From a functional performance training perspective, Dr. Gary Gray has encouraged all movement professionals to look at the motions of the pelvis and the trunk in each of the three planes in order to understand the biomechanics of any activity. At Gray Institute®, if the pelvis and trunk move in the same direction, then that is called in-synch (in-phase). If they move opposite, then that is referred to as out-of-synch (anti-phase). Locomotion requires a lot of out-of-synch motion, while many sports activities are made up primarily of in-synch pelvis-trunk coordination. This guides the design of our training and rehabilitation programs.
In the Analysis Movements of 3DMAPS® (3D Movement Analysis & Performance System), the drivers (lunging leg and swinging arms) are rotating in three-dimensional space in an in-phase coordination pattern. The movements can be easily tweaked to create anti-phase coordination. To increase the authenticity of our movements, the majority of our programs should match the pelvis–trunk coordination of the activity the patient / client desires to perform. However, the training / rehab AFS Principle of “starting with success” might dictate that we start in-phase and transition to anti-phase (or vice versa). Also, emphasizing one of the drivers (leg or arms) more than another can change whether the pelvis or the trunk is leading the motion. The global movements of 3DMAPS® affords the movement specialist with the flexibility to create the segmental Chain Reaction® that the patient / client needs.