## 4 Discussion
### Limitation  
While this study adds a unique understanding to current research, it is acknowledged that there are some limitations to the work. It is pertinent to note that all previous investigations into SA by [PERSON] et al. (2016); [PERSON] et al. (2016); [PERSON] et al. (2017); [PERSON] (2018) and [PERSON] (2018) used an optical measurement system (Optojump-next system) to quantify SA. However, the present research project was the first to calculate SA from kinematic data and apply the SA formula. This will make it difficult to directly compare data from other research papers, but comparing tendencies should be possible.  
One limitation that needs to be considered is the weekly running distance mean, which was 33.0 km with a large standard deviation of 20.3 km within the group. Furthermore, there was a significant difference in the mean training volume between male and female runners, namely 40 km and 24 km per week, respectively. [PERSON] et al. (2018) found a significant difference in lower extremity segment kinematics between higher and lower-mileage runners. This needs to be considered when interpreting results from a heterogeneous group.  
The accuracy of identifying gait events through known kinematic correlations could cause minor errors without the use of force plate data. Additionally, some debate exists regarding the accuracy of certain algorithms for predicting gait events. Several kinematic events have been employed to identify the different phases of stance running gait ([PERSON] et al., 2018). To improve the accuracy of the study, the use of a treadmill with an internal force plate or overground running onto force plates may improve the experiment design.  
Treadmills have been found to alter kinematics in comparison to over-ground running. Moreover, it should be noted that SR increases when running on a treadmill in comparison to over-ground running ([PERSON] et al., 2018). [PERSON] et al. (2018) found no significant difference between both over-ground and treadmill running. However, verbal cueing to alter running gait has been seen to transfer from treadmill running to over-ground running ([PERSON] et al., 2018). Future studies should consider over-ground running for training and assessing participants to allow more accurate measurements of SR manipulation on SA.  
A disadvantage of this study was that a single bout of gait re-training was implemented to alter participants' SR. During the study, some participants reported awkwardness while attempting to coordinate their desired SR. It was noted that motor skill acquisition varied between participants, with some needing more coaching and time to adapt to a running pattern. The use of real-time, gradually faded feedback 6-week protocol for running gait re-training would be a more effective intervention ([PERSON] et al., 2018). The use of over-ground running gait re-training and mobile monitoring to alter SR would be valuable in the experiment to improve participant learning.  
As participants used their own running tops, shorts and footwear, this study did not investigate the effect of shoes on the step angle and rate. Also, it was fully recognised that this study had a small sample size, especially when comparing two groups between genders. In addition, we did not record limb lengths and dominance sides, as these were considered a factor. Hopefully, a future study will consider these limitations.