Why Your Workout App Needs a Custom Exercise Library (And What to Look For)

Every serious athlete has hit the same wall. You open your workout tracking app, search for the exercise you are about to do, and find nothing. Or you find something with the right name but the wrong structure: the app wants you to enter sets and reps and a load, and what you are actually doing is a 90-second hold on a static skill with a band around your waist for added resistance.

So you either log something inaccurate, or you skip logging altogether. Both outcomes break the tracking record you have been building.

This is not a niche problem. It affects any athlete whose training does not fit cleanly into the sets-and-reps-and-barbell template that most fitness apps were originally built around. That includes climbers, calisthenics athletes, yoga practitioners, Olympic weightlifters using specialty equipment, powerlifters training with variations that standard libraries do not recognize, and endurance athletes who cross-train with strength work in unusual ways.

The limitation is not the absence of an exercise name in the library. It is the absence of a way to define what metrics that exercise actually uses.

What makes a custom exercise library genuinely useful

A shallow custom exercise feature lets you add a name. You type “Campus Board 4-finger pocket,” save it, and now it exists in the app. The problem: it still forces you to log it as sets and reps with a load, because that is the only template available. The name is custom; the data structure is not.

A deep custom exercise feature lets you define which metrics the exercise uses. For a campus board exercise, you might want: number of moves, finger pocket size (as a difficulty descriptor), RPE, and a session note. For a yoga pose, you want: hold time in seconds, ROM if applicable, and RPE. For an assisted calisthenics hold, you want: band resistance (entered as a negative load), hold time, and RPE.

The difference between these two approaches is the difference between a naming system and a tracking system. One gives you a record of what you did. The other gives you a record of how you performed, which is the thing that reveals progress.

When evaluating whether a workout app’s custom exercise feature is worth using, the key question is: can you define the metrics, or just the name?

Workout Lab’s custom exercise feature

Workout Lab allows subscribers to create custom exercises with any combination of the metrics the app supports: load, reps, time, distance, ROM, and RPE. You choose which metrics apply to each exercise. A new exercise can be built around any subset of these, in any combination.

This makes it possible to log genuinely different types of movement with the precision they require. The exercise appears in your history and analytics the same way built-in exercises do: trend lines, RPE tracking, progress over time. The custom exercise becomes a first-class data record, not a workaround.

Setup examples for five athlete types

The following are concrete setups showing how different athletes would use a custom exercise library to track their specific training needs.

Powerlifter: specialty bar variations. A powerlifter using a safety squat bar, a hex bar for deadlifts, or a football bar for pressing needs to log these as distinct exercises from their standard bar counterparts — the strength development is movement-specific and should be tracked separately. A custom “Safety Bar Squat” exercise using load and reps as metrics, identical in structure to a standard barbell squat, keeps the records clean and allows the athlete to see a separate estimated 1RM trajectory for each bar variation. A custom “Belt Squat” logged the same way creates a trackable progression for the exercise rather than lumping it vaguely into “quad work.” Athletes who track multiple bar variations will want to read the article on why tracking your workouts matters for the framework that makes this data useful over time.

Calisthenics athlete: static holds and progressions. A calisthenics athlete working toward a planche needs to track their planche lean hold time, their support hold time in tuck planche, and their band-assisted full planche hold. Each is a different exercise with hold time as the primary metric. A custom “Tuck Planche Hold” using the Time metric (seconds) and RPE creates a continuous progress record. As the athlete advances to straddle planche, they create a new exercise for that variation. The progression from one variation to the next is visible in the data as distinct exercises, making the skill development timeline clear. For more on how to structure bodyweight tracking more broadly, how to track bodyweight workout progress covers the full methodology.

Rock climber: campus board and fingerboard work. Climbing-specific strength training involves exercises that standard apps do not have and cannot readily approximate. A fingerboard hang uses hold time as the primary metric, with the edge size and body position as context. A custom “Two-Arm Fingerboard Hang (20mm)” using Time (seconds), load (bodyweight plus or minus added weight), and RPE captures the key variables. Campus board work involves number of moves, difficulty (can be captured in a note or as a custom difficulty rating), and RPE. None of these map naturally to a sets-and-reps structure. Custom exercises with the right metrics make them trackable.

Yoga practitioner: pose holds and ROM tracking. A yoga practitioner might want to track three or four key poses across their practice: a hip-opening pose like pigeon (hold time per side, RPE), a balance pose like Warrior III (hold time per side), and their forward fold ROM (centimeters, measured consistently at the same time of day). Each becomes a custom exercise: “Pigeon Pose” with Time and RPE; “Warrior III” with Time; “Forward Fold” with ROM and RPE. Over twelve weeks, these create an actual progress record for the practice. More on the full approach to yoga measurement is covered in how to track yoga progress.

Endurance athlete: cross-training strength work. An endurance athlete using strength training to support their running or cycling often does exercises at lower loads and higher reps than typical strength training prescriptions, and may also track strength endurance exercises by time rather than reps (wall sits, single-leg holds for stability). A custom “Single-Leg Wall Sit” tracked by Time and RPE creates a progress record for a movement that is specifically relevant to running mechanics but does not exist in standard exercise libraries. A custom “Banded Clamshell” tracked by reps and RPE captures hip stability work with the resistance variant that is actually used. These exercises can coexist in the same app as the endurance athlete’s running distance and pace logs, with all data in one place rather than split between specialized apps.

What to look for in a workout app’s custom exercise feature

If you are evaluating apps based on their custom exercise capabilities, these are the characteristics that determine whether the feature will actually serve you:

Metric definition at the exercise level, not the app level. The app should let you choose which metrics each custom exercise uses, not apply a single template to all exercises.

Custom exercises in analytics and trends. A custom exercise that does not appear in the app’s progress charts and history views is just a name in a list. The tracking value comes from seeing the trend over time, the same way you would see it for a built-in exercise.

Sync between devices. Custom exercises that exist only on one device are fragile. If the app is cloud-synced, your custom library persists across phones and reinstalls.

Subscriber-tier access. Most serious apps gate custom exercises behind a paid tier, which is reasonable. Workout Lab’s custom exercise feature is available to subscribers on the monthly (€3.99/month), yearly (€24.99/year), or lifetime (€49.99) plans.

The comparison article on Workout Lab vs Strong, Hevy, and Fitbod covers how custom exercise depth compares across the major tracking apps if you are in the process of evaluating options.

Custom exercises as the long game

The real value of a custom exercise library compounds over time. In the first week, adding a custom exercise is a minor inconvenience compared to logging something inaccurate. By week twelve, you have twelve weeks of clean data on that exercise: a trend line, a consistent RPE record, and a visible progression from where you started.

Every athlete who trains in ways that standard exercise libraries do not cover is either logging inaccurate data or not logging at all. Both outcomes undermine the tracking habit. Custom exercises with the right metric structure solve that problem completely, and they solve it in a way that benefits you indefinitely as long as you continue training.

Tracking any exercise accurately is better than tracking it inaccurately and dramatically better than not tracking it at all. The Workout Lab for every athlete article covers how this philosophy extends across different training disciplines. The key is having an app that adapts to your training rather than requiring your training to adapt to the app.