###### Abstract  
In running, step rate and step angle are important, but the relationship between the two parameters is not clear in the literature. This study aimed to investigate the effect of step rate manipulation on step angle in running. A group of twenty healthy recreational runners aged between 30 and 59 years who regularly run 15-90 km per week were recruited. Kinematic data were recorded using a motion capture system while running on a treadmill. Participants maintained a self-selected speed and then altered their step rate using a metronome and completed three thirty-second trials at the preferred step rate, 10% above the preferred step rate and 10% below the preferred step rate. The results showed that the step angle is not significantly correlated with the step rate and kept at roughly 37 degrees at the preferred step rate and 10% lower than the preferred step rate but increased to 42 deg when the step rate increased to 10% of the preferred step rate. The step angles were not significantly different between the male and female or between sides. This finding provides an understanding of the association of step rate re-training on swing phase parameters. step rate; step angle; step length; running; gender +
Footnote †: journal: Medical  
during a step and the ground\" (See Figure 1). SA is an indirect indicator of swing phase biomechanics related to the vertical component of ground contact forces. A higher SA has been related to reduced ground CT and improved RE [5; 6; 7; 8]. Moreover, [PERSON] et al. [9] identified SR as an indirect factor affecting leg stiffness because of its effect on minimising CT. Therefore, it seems significant to investigate the relationship between SR manipulation and SA due to their intimate association with CT. Note: the curve is the trace of the foot, L is the step length, H is the max height reached by the foot, and \(\alpha\) the step angle. While considerable research exists regarding spatiotemporal parameters during running, there is a lack of research on the relationship between step rate and step angle, nor the report between sex differences when SR is manipulated. In comparison to men, women are nearly twice as likely to have a running injury [10]. It has been suggested that there are lower extremity differences between sex in running kinematics [11]. Only two studies have investigated the influence of sex differences on spatiotemporal step characteristics [12; 13]. However, these studies examined spatiotemporal step characteristics at a constant speed and SR or incremental running test. Hence, the importance of comparing sex differences was considered in this novel study of SR manipulation on spatial step characteristics. Prior research evaluating asymmetry between lower limbs in gait has identified significant differences in kinetic and kinematic measures [14; 15]. [PERSON] et al. demonstrated that never-injured runners had normal levels of asymmetry ranging from 3.1% up to 49.8% for kinetic forces [16]. In this current original investigation into SA utilising motion capture, we sought to identify any spatial asymmetries. The purpose of the present study was three-fold: (1) to investigate if SA has a predicable interaction with SR, (2) to establish if SA differs between genders with SR changes, and (3) to determine any spatial asymmetrical between the left and right sides. It was hypothesised that there would be a significant correlation between SA and SR, and significant SA differences were found between (a) sex and (b) lower limb symmetry. The reason for investigating step angle with varying step rates was to determine if this parameter is comparable at all step rate changes, not just increased step rates as seen with increased running speed, previously found in other studies. It is also important to measure and compare spatial parameters such as SL and SH, as these are components of SA and could provide a further understanding of the relationships between these parameters.