Stride Length (SL), Stride Frequency (SF), and running velocity are very basic kinematic descriptor for running. SL increase when the velocity increase across the submaximal running velocity (Cummins, 2013). A stride is defined when the movements from a discrete event on one side to the very next same discrete event of the same side. For example, the movement between the time of a right foot contact to the time of the next right foot contact. Stride frequency is state that how quickly a stride is completed and represented using units of Strides/s. According to Daniels (2005), many Olympic runner are running at least 10% slow pace than 5000m runner but have the same amount number of SFs of 91-93 Strides min -1.
The recommended SL and SR is different depend on individual, the recommendation is based on all running distance, elite runner have at lease 90 Strides per mins, its seem to be doubtful that this SF is optimal for every runner at every speed (Lieberman,2015). But of course, the proper way to find the recommend SR and SL is to do it on a formula depends on body height, Leg length and the speed.
There a lot factor that can affect an individual SR and SL, some study shows that treadmill tend to have shorter stride length while running at faster velocity or speed versus on over ground (Elliott, 1976). However, the relationships between SL, SR and velocity have not been directly compared to over ground and treadmill.
Another factor that can affect the SL and SR is the height of the body, the taller the person are able to take longer stride than a short person. A previous research has shown that the SL used during the run is an important predictor of run times, and triathlon performance which the better the performer, maintained the longer and more consistent SL (Landers, 2011).
Another factor is leg stiffness, the musculoskeletal system alters the mechanical behavior of the spring system, where when the step frequency is control while running. The impact of the ground contact time specifically appears to be strong and direct determinant of leg stiffness.
On Stride Rate (SR), the mean of SR is 0.28 on 1.5m/s, because there a consistent number that everyone in the group is 0.26, for example Alex, Jermin and Jeremy. Like a study shown that Height do actually affect each individual person SR and SL (Landers, 2011). Because Alex and Jermin have the same height and same legs length, so they have to same result. In case of Jeremy because he has a very huge body mass, which can also have affected SR and SL if a person has a heavy body weight but the factor only affects a little bit.
On 2.5m/s we have the mean of 0.36, the fastest is Jing Xuan and the slower SR is having 3 person which is Yen Zen, Tommy and Jian Yong. On the speed of 3.5m/s the fastest is Tok Zhen Xian 0.33. we can actually see that the leg length does actually affect on each individual, for example Jing Xuan’s leg length is 80cm, that’s means she can finished her SR in the speed on 2.5m/s because her leg is shorter than guys, which result in she finished her step faster.
On Stride Length, we can see that the mean changes drastically in 3 different speed. Because then the speed of the treadmill getting faster, the length between the leg changing Is getting further and further away. For example, Tok Zhen Xian, he is the tallest guy in the group, so when he run at the speed of 3.5m/s, his stride length is 2.93. The reason is his leg is longer than other person, its takes longer than for his length exchange while running on the treadmill.
The study has suggested that increase stride rate affects impact peak, kinematic and kinetics. It will be take as considered as a mechanism with influence injury risk and recover of runner. Study shows that when hips, knee, and ankle as step rate is increase, Stride length will decrease at a constant speed.