Blog

Power is essential for athletic performance, underpinning movements such as sprinting, jumping, and change of direction2. I’m fortunate to have access to both the 1080 Sprint and Keiser machines, allowing me to track my players’ power outputs in real time. The athletes who rank highest in relative and absolute power on these machines are also the same ones who leave defenders grasping at air or who dominate collisions.  

In my squad of 40+ professional rugby players, the 10 who have played at the international level consistently rank near the top in power output, making it clear that to compete at the highest level, elite physical qualities are just as crucial as technical skill. The inverse is also true. Without disrespecting the athletes, it’s evident that those who lack the necessary physical qualities—whether due to genetics or a poor attitude toward physical development—will struggle to reach the next level. No matter how skilled they are, they need a certain level of power and strength for elite competition.  

Maximising power output requires an understanding of the relationship between force and velocity. Cormie et al.3 describe power as the product of force and velocity, meaning that improvements in either quality will improve power output. The force-velocity curve tells us that that as movement velocity increases, the capacity to produce force decreases—which emphasizes the need for a training approach that develops both maximal strength and high-speed force production3. We also need to consider that the ability to generate force quickly is controlled by the neuromuscular system’s capacity to recruit motor units, synchronise firing patterns, and optimise muscle-tendon interactions.  

Let’s take for example two international level rugby players on my team. Athlete #1 squats 200kg like it is nothing and has a 1RM Bench Press of 180kg. Athlete #2 has a 1RM squat of 180kg  and maxes out on bench at 150kg. We can safely say Athlete #1 is stronger. Yet if you ask all the players in the squad who they hate to tackle, it is Athlete #2. His ability to go from zero to 100% is superhuman. When he gets the ball, he is able to use all his force in the shortest amount of time. So whilst ‘gym strong’ is cool, the transfer to the field can be limited if we don’t train correctly. 

Targeting Power in Training 

The stretch-shortening cycle (SSC) is a critical factor in power development. This mechanism, present in plyometric and ballistic movements, allows stored elastic energy from an eccentric contraction to be utilised in the subsequent concentric phase, increasing overall force production4. Most land-based sports rely heavily on SSC efficiency, making it a fundamental component of power training practices. 

Training methods aimed at improving power typically involve a combination of resistance training, ballistic exercises, plyometrics, and weightlifting movements. Each modality influences power production differently: 

• Traditional, free weight strength training increases maximal force output. 

• Ballistic exercises reduce the deceleration phase and promote rapid force production. 

• Plyometrics optimise neuromuscular efficiency through the SSC.  

More recent innovations, such as pneumatic resistance systems, introduce a unique method of developing power by providing consistent resistance across the movement, eliminating the effect of inertia and momentum, which impacts free weight resistance training modalities7. 

Keiser Fitness is probably the most well-known producer of pneumatic fitness machines in the USA, and these are the machines that I use with my team. 

The Role of Gravity and Inertia in Pneumatic Resistance 

A key distinction between pneumatic machines and free weights is the way resistance is applied. In traditional resistance training, gravity directly influences the resistance (i.e., dumbbell, barbell, or weight stack), meaning that inertia and momentum play significant roles in movement execution. When lifting free weights or using weight stacks, the mass must be accelerated against gravity (overcoming the inertia), and momentum can increase as the lift progresses. This momentum can reduce the effort required later in the movement and necessitates an extended deceleration phase at the top of the lift to control the load. 

Pneumatic resistance, on the other hand, is independent of gravity because the resistance is generated by compressed air rather than mass. This eliminates the inertia and momentum effects seen when lifting free weights, allowing for a more consistent application of force throughout the movement. Without the need to decelerate as significantly at the end of the lift, athletes can maintain higher velocities for longer through the exercise, which create unique neuromuscular and velocity-specific adaptations6,9. The low-mass and low-inertia resistance of pneumatic systems also allows for greater velocities in the early portion of movement, whereas free weights are limited here due to their inherent inertia6,7,9.   

Although pneumatic resistance has unique benefits, I don’t program it in the off-season since some players don’t have access to the machines, and it’s good to mix things up when they go home. I also don’t include training with pneumatic resistance in the preseason—in this 6-8 week block we have 4-6 gym sessions per week, plus running, off-feet conditioning, and rugby sessions. Instead, I keep the Keiser tools in my deck of cards to play later. 

When I do bring the method in, it’s either on a lower body day—contrasted with a heavy lift, some jumps, or in some cases a tri-set—or on a power day (two days before game day). On power days, I’ll typically pair the Keiser Squat with jumps (vertical emphasis) and the Keiser Runner with sleds or the 1080 (horizontal emphasis). 

Most of my athletes love the Keiser machines because they require minimal technical skill and provide live feedback. If I’m using GymAware on barbells and asking players to clean or high pull, technique plays a big role in power output. Sometimes athletes start chasing numbers and their technique becomes questionable. That’s where the Keiser is great, it levels the playing field by taking technique out of the equation; in my opinion, this makes it a safer option for building weight room competition. 

Pneumatic Resistance vs. Other Training Modalities 

Pneumatic resistance offers several practical benefits, particularly due to the ability to maintain constant resistance regardless of movement speed. This feature decreases the deceleration phase commonly associated with free weight training, allowing for the development of high-velocity movements over a long range5,9. Additionally, pneumatic systems minimise momentum effects, which are prevalent in traditional resistance training and can decrease force output and neuromuscular activation at certain phases of the lift6. If you think about a barbell high pull, the hardest part is getting the bar off the floor and building momentum through the first and second pull. Once at the end of that second pull, momentum takes over, and at that point your arms are just guiding the bar. 

That’s where the Keiser Squat is different. Frost et al.5 found that peak movement velocities were significantly higher with pneumatic systems compared to free weights, especially at lighter loads. The key difference? With a Keiser, you accelerate throughout almost the entire movement because momentum isn’t doing the work for you. 

Another study, this time comparing pneumatic and flywheel resistance training in professional handball players8, found both training modalities significantly improved power, throwing speed, and torque. Flywheel training, however, led to slightly greater hypertrophy due to its eccentric overload. The authors did state that the advantage of pneumatic training was that it improved performance without the additional fatigue incurred by flywheel training, which they suggest is useful when wanting to improve performance whilst limiting fatigue. 

Practical Applications for Coaches 

The integration of pneumatic resistance into training programs is promising, as research shows pneumatic resistance results in greater velocity and power outputs at lighter loads6 compared to free weights. As a coach, this is generally an area we call speed strength, as shown in Figure 2.  

Load Selection

Before programming a Keiser training block, I always run a load-power profile with my athletes. I typically incorporate this into a bye week or the first session of a new block to establish individualised training loads. 

For larger athletes, the profile on the Keiser Squat consists of 3 reps at 175lbs, 200lbs, 225lbs, 250lbs, and 275lbs, while the biggest players start at 225lbs and progress up to 300lbs or 325lbs. Lighter athletes typically begin at 150-175lbs and finish between 225-250lbs. The load at which an athlete achieves peak power generally becomes their working resistance for that training block. Sometimes I will program lighter loads to work the speed strength quality. 

When profiling on the Keiser Runner, the athletes still execute 3 reps but each start with a resistance of 150lbs and increase in 20lb increments. In my experience, most athletes reach their peak power between 190lbs and 210lbs, so there’s no need for larger 25lb jumps or excessive loading, such as 300 lbs, which wouldn’t be practical for this movement. 

I use this profiling method because it is efficient for large squads, especially when limited to one Keiser Squat or Runner. While the Keiser system does offer an automated force-velocity profiling tool, which gives the athlete their optimum resistance for power, it does take 2-3 minutes to complete. In contrast, my method allows me to run five athletes through a set in the same time it would take to complete a single profile on the machine, making it a practical and effective alternative. 

Squat Height 

I use a half-squat height, as most actions in rugby that require fast velocity contractions—think accelerating, sprinting, and jumping—occur at shallower joint angles rather than in parallel or deep squat positions.  

Sets & Reps

When programming on the Keiser Squat or Keiser Runner, I typically stick to 3-4 sets, as I find that beyond this, the quality of power output declines noticeably. In terms of reps, I consider 3 to be the minimum and often use the percentage drop-off method to regulate volume and maintain power output. One of the key advantages of Keiser machines is they provide feedback for every rep. On the A300 system (which is what I have), the display screen shows the best power score and then tracks each subsequent rep as a percentage of that max output. This allows for real-time performance monitoring and precise control over fatigue. 

Video 1. Athlete performs 3 reps on the Keiser A300 Squat system. 

Video 2. Live feedback on the data screens from the Keiser Squat. 

I’ve experimented with both 10% and 20% drop-off thresholds in programming. With a 10% drop-off, athletes typically complete 5-8 reps before their output falls below 90% of their best effort. However, when using a 20% drop-off (where the athlete stops once they reach 80% of peak power), some athletes have performed 15-20 reps, which is a significant volume! Because of this, I generally prefer 10% drop-offs to maintain high-intensity efforts without excessive fatigue. 

Exercise Flow 

With my group of professional rugby players, I use a combination of free weights, pneumatic resistance, and plyometrics to target the strength speed > power > speed strength > speed qualities. I program Olympic lifts (cleans and high pulls) between 60-80% 1RM to focus on rate of force development (RFD) and strength speed, followed by Keiser Squats/Runner at a resistance that elicits max power, and then plyometrics (which for this block is continuous hurdle jumps (50cm) with minimal ground contact time). 

I tend to program this as a tri-set, with 1-2 minutes rest between each exercise. I know there are some coaches out there who may find it best to just focus on one lift and juice it for what it’s worth, but my athletes and I love the feeling of surfing the velocity curve—and by the time athletes get to the jumps after cleaning and performing a set of explosive squats, they feel elastic! 

Creating Competition to Improve Power 

I cannot say that the improvements seen on a Keiser Squat or Runner transfer directly to the rugby field. All I can do is try and move the needle to improve my athlete’s relative power. One way I do this is by creating competition among my group of athletes. In Figure 2, you will see a table that is posted in the gym next to the Keiser Squat. Players can compare themselves to their teammates, and this provides external motivation. This table also keeps athletes accountable and serves as internal motivation. 

Generally, my backs will have better relative scores (watts per kilogram) compared to my forwards, whilst my forwards will have better absolute scores. For my backs, who weigh between 76-103kg, I consider anything over 40 w/kg as gold standard. My forwards, who weigh between 98-130kg, I consider anything over 37 w/kg as gold standard. This is not a pure science, just based on my observations. I will point out I have a forward, weighing 117kg, who has a relative score of 50. This guy is a coach’s dream.  

Case Study – Keiser Squat Technique and Influence on Peak Power

A common question my athletes ask is, “Which technique is best for maximising power?” While I had my suspicions, I wanted a science-backed answer—so I decided to run a test. 

I assessed 14 professional rugby players on the Keiser Squat to determine how different techniques influenced peak power output. Each athlete performed squats at a calibrated half-squat height, using a resistance that elicited their peak power (PMax) based on prior load-power profiling. The three techniques tested were: 

• Continuous rebound for 3 reps. 

• 3-second pause at the bottom for 3 reps. 

• 3-second pause at the top for 3 reps. 

To eliminate order effects, techniques were performed in a randomised sequence. 

This is what I found (also shown in Figure 3): 

• Continuous rebound: 3328 W ± 128 (95% CI: 3052-3603 W) 

• 3-second pause at the top: 3328 W ± 134 (95% CI: 3039-3617 W) 

• 3-second pause at the bottom: 3079 W ± 126 (95% CI: 2807-3351 W) 

A quick analysis confirmed that technique significantly influenced peak power (p = 0.003). The continuous rebound and 3-seond pause at the top produced nearly identical results (p = 1.00), while the 3-second pause at the bottom resulted in significantly lower power output (p = 0.04) compared to the other two methods. 

The key takeaway is that when looking to maximise power output on the Keiser Squat, both the continuous rebound and 3-second pause at the top methods are equally effective. The pause at the bottom, while potentially valuable for developing concentric power, led to a decrease in power due to the loss of elastic energy typically present in a continuous movement. 

Keiser Runner Technique

The Keiser Runner was designed to bridge the gap between the gym and the track (or, in my case, the gym and the rugby field). The machine allows for athletes to build what I term “specific power” due to the angle of force application and the way it mimics the acceleration phase of the sprint. 

There are two main ways to set up in the machine: 

1. Both feet in the pedals (as shown in the first video). 

1. One foot in the pedal, the other on the floor acting as a wedge for stability. 

Video 3. Athlete using the Keiser Runner with both legs involved in the exercise. 

Video 4. Athlete performs 1-leg exercise using the Keiser Runner. 

Two things to note when using the Keiser Runner: 

First, I always use the 1-leg option with my squad because it consistently produces higher power scores. The added stability from “wedging” yourself between the shoulder pads and the ground allows for greater force production. More stability equals more output—just like how bench pressing on a solid bench generates more force than pressing on a Swiss ball. 

Second, proper setup is crucial. Without it, athletes won’t limit their power output and it may reinforce poor mechanics. Here’s what I mean: 

• A “short” setup is when the shoulder pads are too low, forcing a folding of the hips, and this subsequently limits full hip extension.

• A “tall” setup is when the shoulder pads are too high. While this setup may look ideal at first, once the athlete starts pumping their legs, the hips drop forward, the lower back extends, and power output decreases. 

• The optimal setup happens with a near-perfect line from ankle to head. I call this a “stacked” setup, where the athlete feels “tight”, allowing for efficient power transfer with every leg drive. 

Limitations of Pneumatic Resistance Training

As much as I value pneumatic machines, they do have limitations—primarily, a limited effectiveness in developing maximal strength and hypertrophy compared to other training modalities8,9. Also, while not a major drawback, Frost et al.5 found that peak power outputs were comparable between pneumatic and free weights at higher relative loads, suggesting that both modalities are effective in developing power.  

If the goal is to maximise RFD, however, Olympic lifts provide a superior method by leveraging the inertial properties of mass7. Additionally, Balachandran et al.1 reported that while pneumatic resistance improved lower body power in older adults, plate-loaded machines demonstrated similar effectiveness, particularly for upper body strength development.  

Conclusion

At the end of the day, pneumatic resistance is just another tool in the toolbox. It’s not a magic bullet, but when used correctly, it can add a lot of value to a well-rounded program. The biggest advantages? Pneumatic resistance allows athletes to accelerate throughout almost the entire movement, eliminates momentum doing the work for them, and provides live feedback to keep them competing. That’s why I keep it in my programming, especially when I’m targeting speed-strength and power development. 

That said, it’s not the answer for everything. If I’m looking to build max strength or hypertrophy, I’ll lean on traditional free weights. If I want to develop strength-speed qualities, Olympic lifts still have their place. Pneumatic resistance shines when I need high-velocity, low-fatigue work. 

So, do I think Keiser and pneumatic resistance make athletes better rugby players? Not directly. But do they help improve the physical qualities that separate great players from good ones? Absolutely. At the elite level, small margins make a big difference, and if I can give my athletes any edge, I’m taking it. 

Ultimately, it’s about understanding what each tool does best and using it at the right time, in the right way, for the right athlete. That’s coaching. 

References 

1. Balachandran AT, Gandia K, Jacobs KA, Streiner DL, Eltoukhy M, Signorile JF. Power training using pneumatic machines vs. plate-loaded machines to improve muscle power in older adults. Exp Gerontol. 2017 Nov; 98:134-142. doi: 10.1016/j.exger.2017.08.009. Epub 2017 Aug 10. PMID: 28804046.
2. Cronin JB, Hansen KT. Strength and power predictors of sports speed. J Strength Cond Res. 2005 May;19(2):349-57. doi: 10.1519/14323.1. PMID: 15903374.
3. 3. Cormie P, McGuigan MR, Newton RU. Developing maximal neuromuscular power: Part 1–biological basis of maximal power production. Sports Med. 2011 Jan 1;41(1):17-38. doi: 10.2165/11537690-000000000-00000. PMID: 21142282.
4. 4. Cormie P, McGuigan MR, Newton RU. Developing maximal neuromuscular power: part 2 – training considerations for improving maximal power production. Sports Med. 2011 Feb 1;41(2):125-46. doi: 10.2165/11538500-000000000-00000. PMID: 21244105.
5. 5. Frost DM, Cronin JB, Newton RU. A comparison of the kinematics, kinetics and muscle activity between pneumatic and free weight resistance. Eur J Appl Physiol. 2008 Dec;104(6):937-56. doi: 10.1007/s00421-008-0821-8. Epub 2008 Oct 1. PMID: 18830619.
6. 6. Frost DM, Bronson S, Cronin JB, Newton RU. Changes in Maximal Strength, Velocity, and Power After 8 Weeks of Training With Pneumatic or Free Weight Resistance. J Strength Cond Res. 2016 Apr;30(4):934-44. doi: 10.1519/JSC.0000000000001179. PMID: 26418368.
7. 7. Keiser Corporation. (2023). Keiser Essentials: Machine details and training principles. Keiser Training Systems Manual.
8. 8. Maroto-Izquierdo S, McBride JM, Gonzalez-Diez N, García-López D, González-Gallego J, de Paz JA. Comparison of Flywheel and Pneumatic Training on Hypertrophy, Strength, and Power in Professional Handball Players. Res Q Exerc 2022 Mar;93(1):1-15. doi: 10.1080/02701367.2020.1762836. Epub 2020 Jul 15. PMID: 32669052.
9. 9. Peltonen, H., Häkkinen, K., & Avela, J. (2013). Neuromuscular responses to different resistance loading protocols using pneumatic and weight stack devices. Journal of Electromyography and Kinesiology, 23(1), 118–124.