The frequency domain of ground reaction forces during running in patients with low back pain: comparing with healthy control group

Walking and running frequency domain analysis of ground reaction forces are associated with injuries. Comparison of frequency domain analysis of ground reaction forces could be useful in rehabilitation of low back patients. The objective of this study was to investigate frequency domain of ground reaction forces during running in patients with low back pain compared to healthy control ones.

This study was a semi-experimental. The statistical sample of the present study include forty males that divided into a healthy control group (n=20) and a group of patients with low back pain (n=20). A foot scan system (sampling rate: 300 Hz) was used for measuring ground reaction forces in ten regions of the foot during running. Independent sample t-test was used for statistical analysis. Alpha level was set at p<0.05.

The frequency content with power 99.5% in the Toe 1 region in low back patients group was significantly greater that that healthy group by 50% (P=0.017). Also, the frequency content with power 99.5% in the Toe 1-5 region in low back patients group was significantly lower than that healthy group (P=0.007). Number of essential harmonics in forth metatarsal in low back patients group was greater than that healthy ones (P=0.049).

Patients with low back pain had lower running speed than that healthy ones and therefore lower values of most of the components of the frequency may be due to the guarded gait mechanism in these patients. This altered running speed and lower frequency content is suggestive of a lower mechanical efficiency of running in patients with low back pain.