Comparison

FlexPro Grip vs TheStack Baseball

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

FlexPro Grip

This app works with a specialized device to create customized training programs for baseball pitchers. It measures baseline strength and endurance to improve pitching performance, reduce injury risk, and accelerate recovery. Track your progress with saved workout history.

Highlights
  • Customized training protocols
  • Strength, endurance, and RPD testing
  • Objective data measurements
  • Injury risk reduction
  • Performance enhancement
  • Workout history tracking
Features
Read full description

OVERVIEW: The FlexPro Grip app is to be used along with the FlexPro Grip device. Designed primarily for baseball pitchers, the FlexPro Grip app provides customized training protocols to be performed on the FlexPro Grip device to improve the strength, endurance and explosiveness of the muscles and tendons from your fingertips through your elbow that most impact pitching performance. There is no guesswork. All data measurements are objective. The result: reduce the chance of tearing your UCL improve your spin rate increase your pitch movement throw harder enhance your command last longer in games recover faster after you throw accelerate your rehab if you are recovering from a UCL injury / forearm strain HOW APP WORKS: The app first guides you through a Strength, Endurance, and / or Rate of Force Development test to measure your baseline levels. Then, the app prescribes you with customized training protocols that specify the amount of force to apply, hold times, and the number of sets, reps, exercises to perform to help you make rapid gains in both your health and pitching performance. All workouts are saved to your History so you can track your progress at any time. NO MEDICAL ADVICE: The protocols are intended to provide recommendations but do not constitute medical advice. As with any form of sports or physical training, seek professional medical advice prior to initiating use.

About

TheStack Baseball

Enhance your baseball performance by increasing bat speed through dynamic, personalized training programs. Track your progress, connect with other players and coaches, and optimize your workouts for maximum gains. Requires a Stack Bat to begin.

Highlights
  • Dynamic training programs
  • Personalized speed trainer
  • Track speed and metrics
  • Connect with other players
  • Team monitoring for coaches
  • Variable inertia speed training
Features
Read full description

Biohack your Bat Speed so that you can swing faster & play better. From the team that brought you the Award-Winning Stack System loved by over 45,000 golfers, Dr. Sasho MacKenzie has now applied his years of speed research to create the most effective way to increase your bat speed. Players, Coaches, and Organizations across all levels of baseball can now systematically gain bat speed to hit the ball harder, farther, and have more success at the plate. What’s Inside TheStack Baseball App: * Dynamic Training Programs Customized variable inertia speed training (precision overload and overspeed) - the most efficient way to increase your bat speed. The App responds to your progress and continuously optimizes your training. The algorithms that power dynamic programming come from years of research by leading sports scientist, Dr. Sasho MacKenzie and insights from over 25 million swings from The Stack System golf’s solution. * Your Own Personal Speed Trainer Be guided through scheduled workouts while tracking Stack weight, rest, recovery, and performance gains. This information allows future workouts to be adjusted behind the scenes, so your training is optimized to maximize bat speed gains. * Track Speed, Share Metrics Seamless connection to the Stack Sensor, which is integrated into the TheStack Bat. Train anywhere, anytime. Track key performance metrics such as Stack Speed, Distance Potential, Bat Speed and Grit Score. Easily share your progress and gains. * Connect to Others Easily connect and follow other Stackers' progress and keep each other on track with your training. If you’re a Coach, add your whole team and monitor progress. *** To start speed training, you will need a Stack Bat. Terms of Use: http://www.apple.com/legal/itunes/appstore/dev/stdeula

Screenshots

FlexPro Grip3 screens
TheStack Baseball4 screens

Verdict

The call

The clearest difference is review sentiment: FlexPro Grip at 67% against TheStack Baseball's 0%. FlexPro Grip also leads on ads (none vs shown) and update cadence (weekly vs every 2 months). TheStack Baseball's advantage is rating (4.9 vs 4.1). On price, ratings volume, in-app purchases and device support there is nothing between them.

Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS

CostPrice · In-app purchases · Ads · Monetization

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

ReceptionRating · Positive reviews · Number of ratings

TheStack Baseball holds the better App Store score, 4.9 against 4.1. Both are backed by a comparable volume of ratings — 26 and 53 respectively. Written reviews complicate that: 67% of FlexPro Grip's written reviews are positive against 0% of TheStack Baseball's, so the app with the better star average is not the one people write more warmly about.

UpkeepUpdate frequency

FlexPro Grip ships an update weekly, TheStack Baseball every 2 months. The most recent releases landed on September 10, 2026 and September 16, 2026 respectively.

Scorecard5 real differences · 5 level
FlexPro Grip versus TheStack Baseball: the parameters behind the verdict, then further details
ParameterFlexPro GripTheStack Baseball
PriceFreeFree
Rating4.1 (26 ratings)4.9 (53 ratings) — better
Positive reviews66.7% of reviews — better0.0% of reviews
Number of ratings2653 — better
Update frequencyWeekly — betterEvery 2 months
AdsNo — betterYes
In-app purchasesNoNo
MonetizationFree — betterAd-supported
DevicesiPhone, iPodiPhone, iPod
Requires iOS15.115.0 — better
Further details — not scored
Size93 MB121 MB
Age rating4+4+
DeveloperFlexProGripThe Stack System Baseball GP, Inc.

Customer experience

FlexPro Grip

All ratings26 ratings
Positive76.9%
Neutral0.0%
Negative23.1%
Written reviews9 reviews
Positive66.7%
Neutral0.0%
Negative33.3%

TheStack Baseball

All ratings53 ratings
Positive98.1%
Neutral1.9%
Negative0.0%
Written reviews1 reviews
Positive0.0%
Neutral0.0%
Negative100.0%

In-app purchases

None

FlexPro Grip

No in-app purchases

None

TheStack Baseball

No in-app purchases

Questions

Is FlexPro Grip free?
FlexPro Grip is free to download, with no in-app purchases.
Is TheStack Baseball free?
TheStack Baseball is free to download, with no in-app purchases.
Which has better reviews, FlexPro Grip or TheStack Baseball?
TheStack Baseball is rated higher. FlexPro Grip averages 4.1 out of 5 from 26 ratings, while TheStack Baseball averages 4.9 from 53 ratings.
Do FlexPro Grip or TheStack Baseball have ads?
TheStack Baseball shows ads; FlexPro Grip does not.
Which is updated more often, FlexPro Grip or TheStack Baseball?
FlexPro Grip ships an update weekly, and TheStack Baseball every 2 months. Most recently, FlexPro Grip was updated on September 10, 2026 and TheStack Baseball on September 16, 2026.

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