The effects of dorso-lumbar motion restriction on energy use and center of mass movement during running.

The effects of restricting dorso-lumbar spine mobility on oxygen consumption in runners was investigated, as was vertical movement of the body's center of mass. Thermoplastic casting material was fashioned into a rigid orthosis and used to restrict spinal motion during running. Volunteers ran on a treadmill at 2.78 m/sec, under normal conditions and with spinal motion restricted. Oxygen consumption was assessed via a Douglas bag set-up. Separately, vertical movement of the center of mass was assessed with a Panasonic recorder. RESULTS: Casted running resulted in an increase in oxygen consumption (p < 0.01). Casted running resulted in less vertical movement of the body's center of mass (p < 0.01). CONCLUSIONS: Spinal mobility has statistically significant effects on the energy used during running and on the vertical movement of the center of mass. A running style that causes the body to use more energy is inefficient and can lead to earlier onset of fatigue. It can make the runner more prone to overuse injuries. We hypothesize that less movement of the center of mass vertically can affect stride length, lead to more strides being used to cover a specific distance and thus could contribute to earlier onset of fatigue and overuse injury. More research needs to be done on this topic.

The effects of dorso-lumbar motion restriction on EMG activity of selected muscles during running.

The effects of restricting dorso-lumbar spine mobility on electromyographic activity of the erector spinae, quadriceps femoris, hamstrings and gastrocnemius muscles in runners was investigated. Thermoplastic casting material was fashioned into a rigid orthosis and used to restrict spinal motion during running. Volunteers ran on a treadmill at 2.78 m/sec, under normal conditions and with spinal motion restricted. Surface electromyographic data was collected during both sets of trials. Normal electromyographic data was also compared with previous authors to determine similarity with their electromyographic data. RESULTS: Casted running resulted in an increase in erector spinae (p < 0.01) and quadriceps femoris (p = 0.02) electromyography activity. Total stride time and swing time of gait were decreased during casted running (p < 0.01), indicating a shift towards shorter and thus more frequent steps to run the same distance. The normal electromyographic data collected was in agreement with previously reported work. CONCLUSIONS: Neurological control over muscle and the fascia surrounding it is responsible for joint movement and load transfer. Experimentally restricting spinal motion during running demonstrated an increase in erector spinae and rectus femoris electromyographic activity. This lends support to the hypothesis that decreased spinal mobility may be a contributing factor to overuse muscle injuries in runners.

The effects of dorso-lumbar motion restriction on the ground reaction force components during running.

PURPOSE: The effects of restricting dorso-lumbar spine mobility on ground reaction forces in runners was measured and assessed. METHODS: A semi-rigid cast was used to restrict spinal motion during running. Subjects ran across a force platform at 3.6 m/s, planting the right foot on the platform. Data was collected from ten running trials with the cast and ten without the cast and analysed. RESULTS: Casted running showed that the initial vertical heel strike maximum was increased (p < .02) and that the anterior-posterior deceleration impulse was increased (p < .01). The maximum vertical ground reaction force was decreased in casted running (p < .01), as was the anterior-posterior acceleration impulse (p < .02). There was a trend for increased medial-lateral impulse in the uncasted state, but this was not statistically significant. CONCLUSIONS: Spinal mobility and fascia contribute to load transfer between joints and body segments. Experimentally restricting spinal motion during running results in measurable and repeatable alterations in ground reaction force components. Alterations in load transfer due to decreased spinal motion may be a factor contributing to selected injuries in runners.