Programming Resisted Sprints on the 1080 Sprint: Setting Speed Limits and the Impact on Sprint Kinetics

The 1080 Sprint is a machine that can be used to train a variety of athletic movements, such as resisted sprints, assisted sprints, jumps, and change of direction activities. A key feature of the 1080 Sprint is the setting where you can manually set the desired velocity of the movement: for example, when performing a resisted sprint, you can set the maximal velocity that the athlete can accelerate to at 4.0 m/s. Or, if performing an assisted sprint, you can set the speed at 9.0 m/s and it will tow the athlete to this speed and then stay at that pace.  

The benefit of training athletes at specific velocities is to strategically overload the kinetic qualities of force and power. As observed in Figure 1 below, there is an inverse linear relationship between force and velocity, and a parabolic (u-shaped) relationship between power and velocity. If you run with a heavy sled, you won’t be going anywhere fast but you will be creating a lot of force. If you make that sled a little lighter, your force output will decrease but you will be moving faster and creating more power.  

Understanding these interactions allows coaches to prescribe resisted sprint training to strategically target the kinetic demands of specific sprint phases.  

The 1080 Sprint traces above illustrate how changing the resistance impacts sprint kinetics. The 20m sprint (red) with 1kg shows the highest velocities, but the lowest force and power outputs. As resistance increases—progressing from 10kg (green) to 20kg (black) and 30kg (yellow)–velocity decreases while force and power outputs increase. The highest force and power outputs are seen in the 30kg (yellow) sprint, showing how heavier resistance shifts the athlete along the force-velocity curve, prioritising force development. It is important to note that the speed limit setting was not applied to these sprints—they are shown purely for demonstration purposes. 

Speed Limit (Velocity Decrements)

In my first article for SimpliFaster, about profiling and programming on the 1080 Sprint, I touched briefly on this speed limit setting. This article is a deeper dive into how I use the speed limit with resisted sprints and then analyse the velocity, force, and power outputs. I will also explain the advantages and disadvantages of using this setting compared to using the traditional load (kg) setting.  

To those not familiar with the 1080 Sprint’s speed limit setting, when performing resisted sprints it functions as a braking system, intermittently engaging to restrict the athlete’s speed. Rather than applying constant resistance, the system activates when the athlete exceeds the set velocity, momentarily braking until the speed drops back below the limit, at which point the resistance eases off. With this intermittent braking application, you will find that there are slight fluctuations above the speed limit during the run, as the braking mechanism continuously adjusts to maintain the target velocity range. 

To those not familiar with the 1080 Sprint’s speed limit setting, when performing resisted sprints, it functions as a braking system, intermittently engaging to restrict the athlete’s speed, Share on X

In my current role, I’m limited to using the 1080 Sprint indoors on just 20 meters of synthetic turf. Previously, however, I was able to use the 1080 Sprint both indoors and outdoors, incorporating resisted and assisted sprints. Despite having less space now, I still see notable improvements in athletes’ acceleration. 

What Is Velocity Decrement?

I will be using this term a lot throughout this article, so first I should define it. Velocity decrement (Vdec) refers to a reduction in an athlete’s sprinting velocity to a predetermined percentage of their maximum velocity. For example, an athlete with a max velocity of 10.0 m/s running with a 50% Vdec will be restricted to 50% of their max velocity, or 5.0 m/s. Other examples can be seen below in Figure 5.  

Key Principles for Using the Speed Limit Setting

The load you decide to program will depend on the stage of the sprint you want to target, and the velocity decrement you will then observe. Two previous articles by George Petrakos can guide you in your programming, with a first part on sled load prescription and second part on programming resisted sprints.  

For me, there are two key principles I use when using the Vdec setting on the 1080 Sprint. 

1. I want the athlete to reach the target velocity before the end of the run—The athlete needs to reach the desired velocity before completing the run to take advantage of the Vdec setting. For example, if my 10.0 m/s athlete is running 15m with 30kg (heaviest setting on the 1080 Sprint Version 1), in addition to a 30% Vdec applied to the run, there is a good chance he won’t hit 7.0 m/s before the end of the 15m—meaning, he will not reap the benefits of the speed limit setting. To address this, I choose a weight that allows the athlete to achieve their target velocity before the end of the run. A general rule of thumb I use is that I want the athlete to hit the desired velocity at the halfway point of the run. So, for a 5m acceleration it would between the 2-3m mark, for a 10m accel at the 5m mark, and a 15m run at the 7-8m mark and so on.  
2. I want minimal disruption to sprint technique when the speed limit kicks in—I want to avoid technical disruptions when the athlete hits the desired velocity. This issue can occur when a light load is paired with a large velocity decrement, for example 5kg with a 70% Vdec. In this case, the athlete explodes out the start due to the lighter resistance but will experience a sudden jolt as the speed limit kicks in, which has a high chance of disrupting their technique. To prevent this, I select a load that allows a smooth transition from the initial weight through to the desired velocity, allowing the athlete to maintain consistent mechanics throughout the sprint.  

What Is the Benefit of Using the Speed Limit Setting? 

You may be asking: why would I choose to use the speed limit setting if a certain load on the 1080 Sprint will cause the velocity reduction I want? 

1. For large groups of athletes who have not yet undergone load-velocity profiling, it is difficult to determine the exact load needed to achieve a specific Vdec. If their maximum velocities are known, however, the speed limit setting on the 1080 Sprint allows for individualisation to each athlete.
2. Athletes may accelerate beyond the desired velocity if the prescribed load is too light, meaning the athlete is training outside the intended velocity zone.
3. The external load is insufficient to achieve large velocity decrements (e.g. >60% Vdec). In this case the speed limit setting provides an effective solution to ensure athletes work within the velocity range. 

Case Studies: Three Sprints with Three Different Interventions

Without further delay, let’s dive into the comparisons of the sprint kinetics of three interventions, each utilising different Vdec settings:  

• Large Vdec of 65% over 5 meters. 

• Moderate Vdec of 50% over 10 meters. 

• Small Vdec of 30% over 15 meters. 

Analysing these three interventions provides insight into how velocity restrictions influence sprint kinetics, specifically velocity, force, and power, and shows how resisted sprint training can be tailored to target specific performance adaptations. 

Analysing these interventions provides insight into how velocity restrictions influence sprint kinetics—specifically velocity, force, and power—and shows how resisted sprints can be tailored to target specific adaptations. Share on X

5m Comparisons 

The version 1.0 of the 1080 Sprint machine is limited to a maximum resistance of 30kg, which is not heavy enough for some of my powerful rugby athletes to achieve velocity decrements greater than 50%. For these athletes, combining the 30kg resistance with the speed limit setting allows me to achieve the velocity loss, and the subsequent force and power outputs I’m after.  

Below you will find a comparison 12 professional rugby players. They ran a contrast of a 5m accel with 30kgs, followed by a 3–4-minute rest, and then a 5m accel with the 30kg plus their 65% Vdec speed limit set. They did this twice through, for a total of 4 runs. From this, I averaged their two runs from each protocol and the group results are below. 

The average 65% Vdec of the 12 players equalled 2.9 m/s, and in the right-hand column of the table you will find the percent difference between the two protocols. 

Table 1. Comparison of two 5m accelerations: one using 30kg of resistance and the other 30kg and a 65% Vdec applied. 

From the results, you can see the athletes completed the 5m/30kg protocol faster, and hit higher velocities, compared to the 5m/30kg/65%Vdec protocol. Whilst the average velocity in the 5m/30kg/65%Vdec protocol did not reach 2.9 m/s (as is to be expected over such a short distance with heavy resistance), you can see that the peak velocity was 22.6% lower compared to the 5m/30kg protocol. As previously discussed, the speed limit setting on the 1080 Sprint functions like a dynamic braking system that intermittently activates. This is evident as the peak velocity of 3.1 m/s slightly exceeds the set speed limit, demonstrating how powerful athletes re-accelerate beyond the limit before the system engages to bring them back within the target velocity. 

The force and power outputs demonstrate the other key differences between the two protocols. Average force was 9.3% higher (416 N vs. 379 N), peak force increased by 30.9% (763 N vs. 559 N), and peak power was 14.5% greater (2221 W vs. 1834 W). By contrast, average power was similar, with only a 1.4% difference between the two protocols. 

In summary, the 5m/30kg/65%vdec protocol resulted in higher force and peak power production, which makes it an effective tool for coaches and athletes wanting to overload the early acceleration phase.  

10m comparisons (with 0-5m and 5-10m splits)

Below, you will find individual data from four professional rugby athletes. The athletes completed two protocols on two different days. 

In the first session, they completed three 10m accelerations with a 15kg load and a speed limit set at 50% of each athlete’s Vdec. In the second session, I used the same format but increased the load to 20kg while maintaining the same speed limit. I selected these two loads to compare the initial acceleration phase (0–5m) sprint kinetics and observe whether the acceleration mechanics were impacted when the speed limit initiated on the lighter load (15kg). I can say now that I did not see—and the athletes did not feel—differences in technique between the 15kg and 20kg loads and the transition from load (kg) to the load plus the speed limit looked smooth. 

I then compared these two protocols to previous power profile data I have from each athlete. I took the load (kilogram) that elicited the same 50% Vdec during the 5-10m split to see which protocol resulted in higher force and power outputs. The results can be seen below.  

Table 2. 10m comparison data from 4 pro rugby athletes. 

There is a fair bit of data involved, so let me help you through the first example: 

• Athlete #1’s 50% Vdec was set at 4.2 m/s.  

• In the column headings, you have the three different 10m protocols.  

• The 15kg/50% Vdec, 20kg/50% Vdec, and the load protocol (which for Athlete #1 was with 24kg).  

The athlete accelerated faster with the 15kg and 20kg load, which is to be expected as there was less resistance on the 1080. Yet when looking at the sprint kinetics, the heavier 24kg load resulted in higher force and power outputs during the initial 5m phase. Remember this for later, as you will see a pattern emerge.  

When comparing the 5-10m split, the time to completion is all the same, as are the average velocities—you can also see that the peak velocity in the first two protocols was limited due to the 50% Vdec speed limit that was applied. Moving on to the average and peak force, they are similar with 100 watts separating the average power between the three. You will then notice a spike in peak power in the two 50% Vdec protocols. This is common when the speed limit kicks in, and the athlete has to work against this velocity limit to maintain their velocity.  

To summarise, in the first 5m split, the protocol using only the load (kg) produces higher force and power outputs compared to the lighter load combined with the 50% speed limit. However, in the final 5m split, the average and peak force, as well as average power outputs, are relatively similar across all protocols. The key distinction is a larger spike in peak power observed in the 50% Vdec protocols. You will see this trend was consistent across the rest of the athletes. 

If time constraints prevent you from completing a full load-velocity profile for your athletes, I recommend setting a resistance of 15kg for lighter athletes and 20kg for heavier athletes, combined with their individual 50% Vdec. This approach offers a practical and time-efficient alternative to train your athletes within the desired velocity zone while achieving an effective training stimulus. 

If time constraints prevent you from completing a full load-velocity profile for your athletes, I recommend setting a resistance of 15kg for lighter athletes and 20kg for heavier athletes, combined with their individual 50% Vdec. Share on X

A final note—I have not yet combined the 50% Vdec protocol with the load that naturally limits an athlete to 50% of their max velocity, but I would take an estimated guess and suggest you would get the best of both worlds. During the early acceleration phase, athletes would create higher levels of force and power due to the heavier load, and then as the speed limit setting kicks in, you will have the increase in peak power production. Whether the overall effect (ala faster acceleration) of a load-only protocol versus a speed limited protocol are similar or different remains to be seen, however. 

Comparison of 15m runs with 5kg and a 30% Vdec

The data shown is of an international level (Tier 1) rugby player and is a comparison of his 2 x 15m accelerations. The 1080 was set with 5kg on the cord, with one of the 15m runs also having a 30% Vdec speed limit set, which in his case was 6.2 m/s. I chose 5kg for this athlete to follow the two principles I mentioned at the start of the article:  

• I want the athlete to reach the target velocity before the end of the run. 

• I want minimal disruption to sprint technique when the speed limit kicks in.  

If I could do this exact set-up again, I would have put 3-4kg on the cord so he arrived one to two metres earlier at the desired velocity.  

Below is a summary of the athlete’s splits, with the percentage difference between them. 

 Table 3. Comparison of 15m runs from International-level rugby athlete. 

In the first 10m of the sprint, the differences between the two protocols are minimal, as the athlete is primarily influenced by the 5kg load with the velocity limit yet to take effect. You may notice in the 5-10m split that the peak velocity value in the Vdec protocol is 9% lower, at 6.37 m/s. This tells me that the athlete achieved the desired speed, and the speed limit is starting to kick in.  

Now pay close attention, as the magic is about to happen—in the final 5m the benefits of the Vdec protocol are seen, with force and power outputs increasing by 50-68% to sustain his velocity. Despite his speed being limited, the athlete finishes only 0.03 seconds slower in the Vdec protocol, showing this speed limit protocol’s effectiveness at increasing force and power production while the athlete is still running at higher velocities. The 1080 traces directly below show the athlete speed-limited during the last 5m, in addition to the large spikes seen in their force and power output. 

These protocols, performed >15m, are what I refer to as “Transition Phase” protocols. In rugby, my athletes typically reach 70% of their maximum velocity by the 10m mark. This signifies that my athletes are transitioning from the acceleration phase to the max velocity phase. I use these lightly loaded Vdec protocols to target this transition. Yes, I am aware that sprinters experience the transition phase much later in their runs, but for rugby athletes, as a rule of thumb, anything past 10m could be argued as the beginning of their transition phase. 

Conclusion

Using the speed limit setting on the 1080 Sprint has advantages over the load only protocols. By using predetermined velocity decrements, athletes can train within their individual velocity zones, resulting in higher force and power outputs, most notably in the heavier (e.g. 65% Vdec) and lighter (30% Vdec) protocols. This approach also allows coaches to tailor individual sessions to athletes without completing a load velocity profile, which can be time consuming in larger groups. However, the limitation with using the speed limit setting arises when the optimal load (kg) for each athlete is uncertain. An example of this can be seen in 10m protocols where the 15kg and 20kg loads used alongside a Vdec resulted in lower force and power outputs during the early (0-5m) acceleration phase.  

By using predetermined velocity decrements, athletes can train within their individual velocity zones, resulting in higher force and power outputs, says @jonobward. Share on X

For those of you curious about training in different velocity zones, and the impact this has on performance, I published a research paper with the Australian Strength and Conditioning Association (ASCA) on this topic. I had three groups of professional rugby players each completing a different resisted sprint training protocol. You can read the paper here, and the key takeaway was specificity: you improve performance over the distance you train, and using the appropriate sled loads is crucial to achieving the desired adaptations. 

References 

1. Cross MR, Brughelli M, Samozino P, Brown SR, Morin JB. Optimal Loading for Maximizing Power During Sled-Resisted Sprinting. Int J Sports Physiol Perform. 2017 Sep;12(8):1069-1077. doi: 10.1123/ijspp.2016-0362. Epub 2017 Jan 4. PMID: 28051333.