Comparison of Frequency Spectrum of Running Ground Reaction Forces in Children with Forward Head Posture and Healthy Controls

Running related injuries have different causes. The objective of the present study was to investigate the frequency spectrum of ground reaction forces during stance phase of running in children with forward head posture and healthy controls.

A total of 28 male children were divided into two groups of healthy controls (n=16) and forward head posture (n=12). Two Kistler force platforms (sampling rate: 1000 Hz) were used to record the ground reaction forces during barefoot running. Independent sample t-test was used for statistical analysis. The significance level was set at 0.05.

Findings indicated that running speed in children with forward head was lower than that in the control group (P<0.001). The number of essential harmonics to reach 95% of total energy of the vertical ground reaction force signal in dominant limb in the healthy group was greater than that of forward head group (medium effect size; P=0.001). The frequency content with 99.5% power of the number of essential harmonics of free moment in the forward head group was greater than that of the control group (large effect size; P=0.005). Other components of running ground reaction force frequency content were not statistically different between the two groups (P> 0.05).

Due to lower walking speed in children with forward head posture, lower frequency content indicated lower center of gravity sway. Also, these lower walking velocity and frequency content demonstrated lower mechanical efficiency in children with forward head posture.