To Step or Not to Step is the Question?

To Step or Not to Step is the Question?

The False Step (Plyo- Step)

Long have sport coaches and strength coaches, and strength coaches and strength coaches argued over should athletes take a step back or not to take a step back when starting out of an athletic stance and sprinting linearly. I know I have spend a generous amount of time discussing this topic with coaches and interns which is why I was excited when I came across A Comparison of Three Different Start Techniques on Sprint Speed in Collegiate Linebackers by Cusick et al. in the latest NSCA Journal. We can all agree that the ability to accelerate over short distances is key to athletic success in field sports. We can also agree that the difference a tenth of a second makes in field sports is huge. What we cannot seem to agree with is the idea of taking a False Step (FS) to propel ourselves forward out of an athletic stance is advantageous.

For an athlete to initiate a forward movement from a stationary standing position (athletic stance), the center of mass must be positioned in front of the body (anteriorly) to the base of support (feet). This allows the athlete to have good path for the correct ground reaction force vector upon their first step. An athlete can achieve this in one of two ways: Leaning forwards thereby shifting the center of mass forward, or the athlete can displace the support area behind the center of mass (placing one foot backward = FS). What research shows us is that the time taken to achieve the backwards step does not exceed the time required to shift the center of mass forward. This means that the FS can elicit performance improvements over short distances when compared with a no FS movement.

We know that the efficiency of the acceleration phase has been linked to the execution of the first step, in terms of both horizontal and vertical forces and the temporal characteristics of the ground contact. So when looking at table 1 from Frost and Cronin et al. we can see that the FS has a higher vertical force and lower horizontal peak force than the other two starts. Now why is that even relative when the name of the game when sprinting is to cover as much ground horizontally (distance) over the quickest amount of time. Well in the first initial movement not step the higher horizontal peak force is associated with increased ground contact time which is counterproductive during the first step. While the increased vertical peak force in the first step is helpful to the athlete in increasing their hip flexion allowing for a better thigh drive and more force production with the first true step forward (see figure 1). Table 2 shows us the ground contact time, time to peak force, and time from peak force to take-off all of which are lower with the FS than the other two. The evidence does not lie the FS is far superior when starting in an athletic stance.

TABLE 1. Mean (SD) first step kinetics for each starting style (all participants).*

Vertical                                          Horizontal

StartImpulse (m_s21) Peak force (% BW) Mean force(% BW)

 

Impulse(m_s21)

 

Peak force(% BW)

 

Mean force(% BW)

 

False0.85 (0.32)1.92 (0.28)1.21 (0.19)†1.07 (0.19)†0.89 (0.16)0.51 (0.11)

Parallel0.82 (0.37)1.82 (0.29)1.09 (0.20)1.41 (0.28)0.93 (0.15)0.50 (0.10)

Split0.83 (0.31)1.88 (0.29)1.22 (0.19)†1.10 (0.17)†0.91 (0.16)0.51 (0.10)

*BW = body weight. †Significantly different than the parallel start (p 0.05). *Reproduced from Frost and Cronin et al.

 

 

Figure 1:

 

The false (A), parallel (B), and split (C) starting styles. The false and parallel starts were initiated with a backward step and forward lean, respectively. *Image taken from Frost and Cronin et al.

 

TABLE 2. Mean (SD) temporal characteristics of the first step for each starting style (all participants).*

Vertical                                           Horizontal

StartGCT (ms)TPF (MS)TPF-TO (ms)TPF (ms)TPF-TO (ms)

False213 (19)†122 (18)†91 (9)†147 (16)†67 (8)†

Parallel287 (37)187 (31)100 (13)203 (38)84 (23)

Split218 (22)†126 (20)†92 (18)†148 (24)†70 (21)†

*GCT = ground contact time, TPF = time to peak force, TPF-TO = time from peak force to take-off. †Significantly different than the parallel start (p , 0.05). *Reproduced from Frost and Cronin et al.

 

While this research is a great tool to help strength and conditioning professionals communicate the proper use of the FS to sport coaches, it is not an end all be all. Example is: if I line up 10 athletes I can assume with confidence that 9 out of those 10 with take the FS without me teaching them a thing. I would then attempt to tell the one athlete that it is okay to take a step back to sprint forward. If upon review of his mechanics he is faster with the non-FS I will not force him to take a FS. Not every technique is perfect for everyone the FS included. My attention with this post was to bring awareness to the fact that the FS is not really a False Step but rather a quick repositioning of the foot around the hips to allow the athlete to produces greater forces to step them up for a better first true step. This is no different than teaching your athletes to move their feet into the correct positioning upon cutting. This is why I ask that we refer to the FS as a plyo-step in the future.

We also need to realize that in field sports and court sports an athlete will rarely be starting from an athletic stance. I would suggest that reviewing and teaching the plyo-step be done as an entry level skill when trying to teach athletes to reposition their feet around their hips to aid in acceleration. When teaching speed and agility work always review where the athletes force vectors are going, and analysis them biomechanically not on the time it takes to complete a drill with cones and you will set up your athletes for success on the playing field.

No one way is an absolute, live and learn!

References:

Cusick, Jason L. , Robin J. Lund, and Travis K. Ficklin. "A Comparison of Three Different Start Techniques On Sprint Speed in Collegiate Linebackers." Journal of Strength and Conditioning Research 28.9 (2014): 2669-2672. Print.

Frost, David M., and John B. Cronin. "Stepping Back to Improve Sprint Performance: A Kinetic Analysis of The First Step Forwards." Journal of Strength and Conditioning Research 25.10 (2011): 2721-2728. Print.