The Stack System 4+

Guided speed training for golf

The Stack System, LP

Designed for iPhone

    • 4.9 • 2.2K Ratings
    • Free
    • Offers In-App Purchases

iPhone Screenshots


TheStack App provides customized variable inertia speed training, which is the most efficient way for a golfer to increase their clubhead speed. The algorithms that power the customized dynamic programming come from years of experimental research by leading sport scientist, Dr. Sasho MacKenzie. TheStack App functions as your own personal trainer by guiding you through scheduled workouts while tracking your rest, recovery, and performance gains. This information allows future workouts to be adjusted behind the scenes, so your training is optimized to maximize clubhead speed gains.

Within a training session, TheStack App provides clear images on how to arrange TheStack hardware into one of the 30 possible weight settings for your next set. Configuring TheStack to a specific weight only takes a few seconds and can easily be accomplished while the automated rest timer counts down on screen. Within a training set, take advantage of the optional Voice Entry technology and dictate the speed of each rep into the app after each swing. The Stack System altogether unlocks variable inertia speed training, validated in the lab and proven on the PGA Tour, directly to you. To start, you will need TheStack hardware ( and a Speed Radar (read about options on our website).

How the TheStack App Works

BASELINE SESSION: Just like working with a personal trainer, golfers will be guided through a detailed intake session. Qualitative data will be gathered on perceived strengths and weakness related to generating clubhead speed. Golfers will also be piloted through a series of swing speed tests to generate a force-velocity profile of their current swing. This data informs A.I. algorithms, which create custom programming options.

PROGRAMS: Following the Baseline Session, the app will provide a list of customized programming options. The list is rank ordered starting with the program that will have the greatest likelihood of increasing your clubhead speed over a 6 to 10 week period (18 to 24 training sessions).

TRAINING: While completing a Training Session, within a selected Program, the app seamlessly guides you through a sequence of configuring a specific stack weight, prompting for a speed entry, and displaying a countdown rest timer. You can interact with the App hands-free during a Training Session by using our Voice Entry technology. The App tracks key performance Metrics such as Distance Potential, which is based on speed data, as well as Grit Score (read more on our website), which is based on your rest and recovery data. You can easily share your progress and gains to your favorite social media platform.

PROGRESS CHECK: After you finish a training Program, the App will re-assess you with a Progress Check and reformulate your next Program. Data captured along the way will improve the intelligence of TheStack algorithms through A.I. techniques.

PRE-ROUND SPEED PRIMING: Pre-round speed priming is designed to be used before a competitive round to potentiate your neuromuscular system. It both maximizes your speed potential for that day as well as allows you to attain your preferred on-course speed with less perceived effort.

This session can also be used if you choose to interrupt your current speed training program with a competitive tournament. Pause your program and complete this session before or after your round.

Terms of Use:

What’s New

Version 1.20

* Improved video downloading process
* Fix some unit conversion display issues
* Various bug fixes & enhancements

Ratings and Reviews

4.9 out of 5
2.2K Ratings

2.2K Ratings

Seanjoon ,

Chasing Speed

From one casual weekend golfer who is about to turn 60 years old to all of you we can golfers. This is the product of the century. It truly works. I have a pretty good golfer with a 7.5 index planning at a pretty tough golf course but always lagging driver distance. I started this program about eight weeks ago with a driver speed of 89 mph. An average driver distance of 235 yards. Now my driver speed is 102 miles an hour with my potential yardage of 284 yards. That is 50 yards theoretically but in real life I got 30 yards my buddies are teeing off the white tees and I’m turning off the blue and out driving them where we used to be about the same.

Studzit ,

A golf gem

The Stack is a Golf Gem! It helps you improve on a weekly basis so that when you’re practicing and training you can swing at faster speeds and then when you’re in gametime mode, the distance is there when you need it! Sasho does a great job of helping you understand when rest is needed so that you do not injure yourself. As a right handed, I found that in between the major weight changes swinging left-handed is a good way to stay warmed up. All in all, I would highly recommend this app and I look forward to the improvements two months from now!

cag331 ,

Almost perfect

So far so good - I have only done a handful of sessions so far, but I’ve already added a couple mph to my estimated driver speed. The only complaint I have: please please please give us the ability to listen to music/podcasts/etc. Every time the app gives you a spoken prompt, whatever you are listening to is stopped and you have to manually restart it. Please make it like a navigation app where whatever is playing gets quieter or pauses and then goes back to normal after the prompt.

App Privacy

The developer, The Stack System, LP, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy.

Data Linked to You

The following data may be collected and linked to your identity:

  • Health & Fitness
  • Contact Info
  • User Content
  • Identifiers
  • Usage Data
  • Diagnostics

Privacy practices may vary, for example, based on the features you use or your age. Learn More


  • Family Sharing

    Some in‑app purchases, including subscriptions, may be shareable with your family group when Family Sharing is enabled.

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