User Guide

Getting Started

CurlBro is a free, client-side workout builder that runs entirely in your browser. There is no account to create, no subscription, and no data ever leaves your device. Every workout you build, every log you save, and every setting you configure stays stored locally in your browser using localStorage.

The app is designed around evidence-based resistance training principles drawn from peer-reviewed research by Brad Schoenfeld, Renaissance Periodization (RP), Jeff Nippard, the NSCA, and Stronger By Science. Whether you are a beginner stepping into a gym for the first time or an experienced lifter looking for smarter programming tools, CurlBro gives you the building blocks to create balanced, effective workouts.

Your First Workout in Five Steps

1. 1
   Open the Build tab This is your workout builder. You start here with an empty canvas. Tap the workout name at the top to rename it, or CurlBro will auto-generate a name based on the primary muscle groups you choose.
2. 2
   Choose a workout split (optional) Select a split like Push, Pull, Legs, Upper, Lower, or Full Body. This tells CurlBro which muscle groups to expect, enabling gap analysis that flags muscles you have not covered yet. You can skip this step and build a freeform workout instead.
3. 3
   Add exercises Tap the Add Exercise button to open the Exercise Picker. Search by name, filter by category (compound, isolation, stretch, mobility, cardio), or use smart context filters based on your current body state. Tap an exercise to add it to your workout.
4. 4
   Configure sets, reps, and rest Expand any exercise card to adjust the number of sets, the rep target, weight, rest period between sets, and optional notes. CurlBro pre-fills sensible defaults based on your training goal setting and whether the exercise is a compound or isolation movement.
5. 5
   Save or start your workout When you are happy with your workout, save it to your library for future use, or tap Start Workout to begin an active session with set tracking and rest timers.

Navigating the App

CurlBro has five main tabs, accessible from the bottom navigation bar. You can also swipe left and right on the main content area to navigate between adjacent tabs.

• Build — Create and edit your current workout draft. This is where you add exercises, set parameters, and organize your routine.
• Library — Browse your saved workouts and the 16 built-in templates. Saved workouts persist across sessions. Templates are always available and cannot be deleted.
• Active — Your in-progress workout session. Appears when you start a workout. Track sets, log weights and reps, and use the built-in rest timer.
• Log — View your workout history. Each completed session is saved here with detailed statistics including total volume, completion percentage, and duration.
• Settings — Configure your training goal, default sets and reps, rest timer durations, export preferences, and manage your data.

Exercise Database

CurlBro includes a curated and growing exercise database organized across six categories. Every exercise has been selected for its training value and includes detailed metadata: primary and secondary muscles targeted, equipment required, movement pattern, difficulty level, recommended rep ranges for both hypertrophy and strength goals, superset candidates, complementary exercises, and substitutes.

Exercise Categories

Muscle Groups

CurlBro tracks exercise coverage across all major muscle groups. When you build a workout, the app analyzes which muscles are being targeted as primary movers and which are working as secondary stabilizers.

Exercise Metadata

Each exercise in the database includes the following attributes, which CurlBro uses to power its intelligent features like conflict detection, superset suggestions, and gap analysis:

• Movement pattern — Categorizes how the exercise moves (e.g., hip hinge, vertical push, horizontal pull, squat, isolation). Used for pattern-level conflict detection.
• Force type — Push, pull, or isometric. Used for push/pull balance analysis.
• Equipment — All required equipment (barbell, dumbbell, cable machine, etc.). CurlBro supports over 40 equipment types including machines, free weights, bodyweight, and cardio equipment.
• Workout position — Where the exercise should ideally appear in a session (early, early-mid, mid, mid-late, late). Compounds go early; isolations go late.
• Difficulty — Beginner, intermediate, or advanced. Helps filter exercises appropriate for your experience level.
• Rep ranges — Separate recommendations for hypertrophy and strength goals, drawn from current evidence (Schoenfeld 2017 meta-analysis).
• Relationships — Each exercise lists substitutes (alternatives that target the same muscles), complements (exercises that pair well), and superset candidates (exercises suitable for back-to-back pairing with minimal rest).

Building a Workout

The Build tab is your primary workspace. Here you construct workouts exercise by exercise, configuring every parameter to match your training goals. CurlBro provides real-time feedback as you build: conflict warnings when exercise pairings are risky, gap analysis showing which muscles still need attention, and smart suggestions for complementary exercises.

Naming Your Workout

Tap the workout name at the top of the Build tab to edit it. If you leave it blank, CurlBro auto-generates a name based on the most common primary muscle group in your workout combined with the current date (for example, "Chest — Mar 5"). This automatic naming gives you a useful reference when browsing your saved workouts later.

Selecting a Split

Below the workout name, you will find the optional split selector. CurlBro supports six standard workout splits, each with defined primary and secondary muscle group targets:

• Push — Chest, shoulders, and triceps as primary targets. Traps and core as secondary.
• Pull — Back, biceps, and traps as primary targets. Shoulders, forearms, and core as secondary.
• Legs — Quads, hamstrings, and glutes as primary targets. Calves, adductors, abductors, and core as secondary.
• Upper — Chest, back, shoulders, and traps as primary. Biceps, triceps, forearms, and core as secondary.
• Lower — Same primary targets as Legs (quads, hamstrings, glutes), designed to pair with Upper in an Upper/Lower rotation.
• Full Body — All six major groups (chest, back, shoulders, quads, hamstrings, glutes) as primary. All remaining muscles as secondary.

Selecting a split enables gap analysis, which shows you in real time which primary muscles you have covered and which you still need to target. You can change or remove the split at any time without losing your exercises.

Adding and Configuring Exercises

Tap Add Exercise to open the Exercise Picker (covered in detail in the next section). Once you add an exercise, it appears as a card in your workout. Tap any exercise card to expand it and reveal the full configuration panel:

• Sets — Number of working sets. CurlBro defaults to your configured default (typically 4 for compounds, 3 for isolations), but you can adjust from 1 to 10.
• Reps — Rep target per set. Pre-filled based on your training goal (strength: lower range, hypertrophy: moderate range, endurance: higher range) and the exercise's recommended rep range data.
• Weight — Optional weight in pounds or kilograms. Leave blank for bodyweight exercises or if you prefer not to pre-plan weights.
• Rest — Rest period between sets in seconds. Defaults are based on your settings: compounds typically get 90–180 seconds, isolations get 45–90 seconds. These follow NSCA rest period guidelines for different training goals.
• Notes — Free-text field for form cues, tempo prescriptions, or any personal reminders. Notes appear during active sessions alongside the exercise.

Reordering Exercises

Drag exercises up and down to reorder them. Exercise order matters: compound movements should generally come before isolation work (NSCA Essentials, 4th ed., Chapter 22), and exercises requiring the most neuromuscular precision should be performed when you are freshest. CurlBro's conflict detection will warn you if you place exercises in a suboptimal order that could increase injury risk.

Removing Exercises

Swipe left on any exercise card to reveal the delete action, or tap the remove button when the card is expanded. Removing an exercise updates the gap analysis and conflict checks immediately.

Saving to Library

When your workout is ready, tap Save to store it in your library. Saved workouts persist across browser sessions. You can load, edit, duplicate, and delete saved workouts at any time. Each saved workout tracks its creation and last-modified timestamps.

Exercise Picker & Smart Filters

The Exercise Picker is where you browse and search the full exercise database. It opens as a full-screen panel with a search bar at the top and filter options below. CurlBro uses Fuse.js for fuzzy search, so you do not need to type exact exercise names — close matches and partial terms work well.

Category Filters

At the top of the picker, category filter chips let you quickly narrow the exercise list by type:

• Strength — Shows compound and isolation exercises. This is the default view and covers the core of most workouts.
• Warm-up — Shows dynamic stretches, mobility drills, and cardio warm-up exercises. Perfect for building a warm-up sequence before your main workout.
• Cool-down — Shows static stretches and mobility exercises. These are designed for post-workout recovery and flexibility development.

Context-Aware Smart Filters

CurlBro's most powerful feature in the Exercise Picker is its context-aware filtering system. These filters use information from the Body State Input panel (available on the Build tab) to intelligently recommend or exclude exercises based on your current physical state.

Body State Input

Before opening the Exercise Picker, you can optionally record your current body state. This involves two inputs:

• Muscle soreness — Rate soreness for each muscle group on a four-level scale: None, Mild, Moderate, or Severe. This data persists between sessions so you only need to update what has changed.
• Recent activities — Log any recent physical activity outside of gym training: running, cycling, swimming, hiking, sports, or yoga. You can specify whether the activity happened yesterday, today, or is planned for tomorrow. Each activity type is mapped to the muscle groups it impacts (for example, running impacts quads, hamstrings, glutes, and calves).

Smart Filter Types

When body state data is present, CurlBro generates smart filter chips that appear in the Exercise Picker:

• Avoid sore Chest — Excludes exercises that primarily target a muscle group you have marked as moderately or severely sore. Mildly sore muscles are still included but flagged.
• Post-run recovery — If you logged a run yesterday, this filter surfaces dynamic stretches and mobility exercises targeting the muscles impacted by running (quads, hamstrings, glutes, calves).
• Pre-hike warm-up — If you have a hike planned for tomorrow, this filter shows warm-up exercises for the muscle groups you will need, helping you prepare the day before.
• Light day — Filters to lower-intensity exercises only. Useful when you want to train but your body needs a reduced workload. Excludes heavy compound movements in favor of machine work, isolations, and mobility.

Recovery Badges

When smart filters are active, exercise cards in the search results display colored recovery badges indicating how appropriate each exercise is given your current body state. Green badges indicate fully appropriate exercises, amber badges flag exercises that target muscles with mild soreness (proceed with caution), and exercises targeting severely sore muscles are excluded entirely from the results.

Pre-built Templates

CurlBro ships with pre-built workout templates organized into four tiers. Every template has been designed using evidence-based programming principles from the scientific literature (Schoenfeld, RP, Nippard, NSCA). Templates are bundled with the app and are always available — they cannot be accidentally deleted.

When you open a template, you get a complete, ready-to-use workout with exercises, sets, reps, and rest periods already configured. You can start training immediately, or tap Copy to Builder to customize the template to your preferences.

Programming Principles Behind the Templates

All templates follow these evidence-based principles:

• Compound exercises first — Exercises with the highest neural demand and heaviest loading are placed early in the session when the lifter is freshest (NSCA Essentials, Ch. 22).
• Isolation and machine work last — Lower systemic fatigue exercises finish the session, allowing targeted volume accumulation without compromising safety.
• Rep ranges matched to exercise type — Compounds: 5–8 reps (strength-hypertrophy overlap). Accessories: 8–12 reps (hypertrophy). Isolations: 12–15 reps (hypertrophy-endurance).
• Rest periods by exercise type — Compounds: 120–180 seconds. Accessories: 60–90 seconds. Isolations: 45–60 seconds.
• Shoulder health built in — Face pulls and rear delt work are included in every push and upper-body session, per recommendations from Greg Nuckols and RP.
• Beginner-friendly machines — The Easy Machine tier uses only machines, cables, and bodyweight to eliminate the technique barrier and make the gym less intimidating for new lifters.

Conflict Detection

One of CurlBro's most distinctive features is its exercise conflict detection system. As you add exercises to your workout, CurlBro checks every pair of exercises against a database of 33 known conflicts, each backed by peer-reviewed research. When a conflict is detected, you see an inline warning explaining the risk and suggesting alternatives.

Severity Levels

Conflicts come in two severity levels:

Conflict Categories

The conflicts are organized into evidence-based categories:

1. Spinal compression stacking — Combining exercises that impose peak lumbar compressive forces (squats + deadlifts, good mornings + any heavy spinal loading). Based on McGill (2016) cumulative load research.
2. Shoulder impingement stacking — Horizontal pressing before overhead pressing, or multiple overhead press variations in one session. Based on Cools et al. (2008) and Kolber et al. (2010) rotator cuff fatigue research.
3. Elbow joint stress accumulation — Stacking multiple heavy bilateral curl or heavy tricep extension exercises. Protects the distal bicep tendon, ulnar collateral ligament, and lateral epicondyle.
4. Lumbar stabilizer pre-fatigue — Performing high-demand lumbar stabilizer exercises (deadlift, barbell row, good morning) before other exercises that also require maximal lumbar stability. Based on Willardson (2007).
5. Rotator cuff and scapular stabilizer fatigue — Heavy overhead pressing before pull-ups or chin-ups, where the same stabilizers are needed for safe performance.
6. Knee joint stress accumulation — Multiple heavy knee-extension exercises (squats + leg extensions, hack squats + leg extensions) that accumulate patellofemoral compressive forces.
7. Grip and forearm fatigue — Forearm isolation work (wrist curls) before heavy pulling exercises (deadlifts, rows, pull-ups) that depend on grip integrity for safety.

How Conflicts Are Matched

CurlBro uses three matching strategies to detect conflicts:

• ID-based — Exact exercise pairs. For example, conventional_deadlift + barbell_back_squat. These are specific, research-backed pairings.
• Pattern-based — Movement pattern pairs. For example, any two hip_hinge exercises, or any two vertical_push exercises. These catch broader categories of conflicts.
• Tag-based — Logical groupings defined by exercise properties. For example, "heavy axial spinal load" maps to any exercise that imposes significant lumbar compression.

Gap Analysis

When you select a workout split, CurlBro enables gap analysis — a real-time visualization of which muscle groups your workout covers versus which ones the chosen split expects you to train. This helps you build balanced workouts that do not leave any target muscles behind.

How It Works

Each workout split defines a set of primary and secondary muscle groups (see the "Selecting a Split" section above). As you add exercises to your workout, CurlBro checks each exercise's primary and secondary muscle targets against the split's expected coverage. The result is a status display for each muscle group:

• Covered — At least one exercise in your workout targets this muscle group as a primary mover. You are good to go.
• Secondary only — The muscle is being trained as a secondary stabilizer but not as a primary target. You may want to add a direct exercise for full development.
• Missing — No exercise in your workout targets this muscle group. If it is a primary target for your split, consider adding coverage.

Example: Push Day Gap Analysis

A push day expects chest, shoulders, and triceps as primary targets. If you have added a bench press (chest) and a lateral raise (shoulders) but no tricep exercise, the gap analysis would show:

This visual feedback helps you catch gaps before you save or start the workout. In this example, you would want to add a tricep exercise (like tricep pushdowns or overhead extensions) to complete the push day coverage.

Supersets, Tri-sets & Circuits

CurlBro supports exercise grouping — linking two or more exercises together so they are performed back-to-back with no rest between them. This is one of the most effective techniques for increasing workout density (more work in less time) without sacrificing training quality.

Group Types

• Superset (2 exercises) — Two exercises performed consecutively with rest only after both are completed. Most effective with antagonist pairs (e.g., bench press + barbell row) where one muscle group rests while the other works.
• Tri-set (3 exercises) — Three exercises performed in sequence. Often used for shoulder training (overhead press + lateral raise + rear delt flye) or arm work (barbell curl + skull crusher + hammer curl).
• Giant set / Circuit (4+ exercises) — Four or more exercises in a row. Used for conditioning, pump-focused finishers, or time-efficient full-body sessions.

Creating Groups in CurlBro

To group exercises, select two or more exercise cards in the Build tab and tap the Group action. CurlBro assigns a shared group identifier to the selected exercises and visually links them with a colored accent border and a group label. The group label automatically updates based on the number of exercises: "Superset" for two, "Tri-set" for three, and "Circuit" for four or more.

During Active Sessions

Grouped exercises are navigated as a unit during active workout sessions. When you reach a superset, CurlBro presents the exercises in sequence: complete one set of Exercise A, then immediately proceed to one set of Exercise B. The rest timer starts only after you have completed sets of all exercises in the group. This matches how supersets are intended to be performed — the rest is between rounds, not between exercises within a round.

Superset Suggestions

Each exercise in the CurlBro database includes a list of superset candidates — exercises that pair well for back-to-back performance. These suggestions prioritize antagonist pairings (opposing muscle groups) and non-competing movements, following the evidence that antagonist supersets maintain performance levels comparable to straight sets while significantly reducing total training time (Weakley et al., 2017).

Active Workout Session

The Active tab is where your workout plan becomes reality. When you start a workout (either from a saved workout in your Library or directly from the Builder), CurlBro creates an active session that guides you through each exercise with set tracking, weight logging, and an automatic rest timer.

Session Flow

Here is the typical flow of an active workout session:

Set Tracking

For each exercise, CurlBro displays a row of set indicators based on the planned number of sets. Tap a set to expand it and log:

• Weight — The weight used for this set. CurlBro remembers the last weight you entered and pre-fills subsequent sets, since most lifters use the same weight across working sets.
• Reps — The number of reps completed. Pre-filled with the planned rep target but adjustable if you hit more or fewer reps than planned.
• Completed — Mark the set as completed. Incomplete sets are tracked separately in your log for accurate volume analysis.

Rest Timer

After you complete a set, the rest timer starts automatically. The countdown is based on the rest period configured for that exercise (typically 120–180 seconds for compounds and 45–90 seconds for isolations). You can:

• Skip — Dismiss the timer and proceed immediately to your next set if you feel ready.
• Extend — Add additional time if you need more recovery, common after heavy compound sets near maximal effort.

The timer uses your device's notification system when available, giving you an audible alert when rest is complete so you can focus on recovery without watching the screen.

Navigating Between Exercises

The Active tab displays your current exercise or exercise group prominently. Navigate forward and backward through your workout using the navigation controls or by swiping. The progress indicator at the top shows how far through the session you are.

For grouped exercises (supersets, tri-sets, circuits), all exercises in the group are displayed together. You cycle through sets within the group before moving to the next group or standalone exercise.

Two-Step Save Process

Finishing a session is a deliberate two-step process:

1. Finish — Tap the Finish button to end the session and stop the timer. This marks the session with a completion timestamp but does not yet create a log entry.
2. Save — After finishing, tap Save to create a permanent workout log entry. This records all your set data, weights, reps, and the total session duration. The save has built-in duplicate prevention, so you will not accidentally create two log entries for the same session.

This two-step process gives you a moment to review your session data before committing it to your log. You can also discard the session if it was just a test run.

Workout Log

The Log tab stores your complete workout history. Every session you save creates a detailed log entry that includes every exercise performed, every set logged, all weights and reps recorded, and summary statistics for the session.

Log Entry Details

Each log entry shows:

• Duration — Total time from session start to finish, in minutes.
• Total volume — Calculated as the sum of (weight × reps) across all completed sets. This is the standard volume metric used in training research for tracking progressive overload (Schoenfeld 2017).
• Completion percentage — The percentage of planned sets that were completed. A session with 23 of 24 sets completed shows 96%. This metric helps you identify when you are overreaching (consistently low completion) or ready to increase volume.
• Exercise breakdown — Tap any log entry to see the full exercise-by-exercise breakdown with individual set data.

Converting Logs to Workouts

You can convert any past log entry back into a workout template. This is useful for repeating a session that worked well — tap the convert button on a log entry, and CurlBro creates a new saved workout in your library with the same exercises, sets, reps, and rest periods. Any weights you logged are preserved, giving you a ready-to-use template based on your actual performance.

Import & Export

CurlBro supports a text-based import and export format that makes it easy to share workouts with friends, save them outside the app, or generate them using an AI assistant like ChatGPT.

Export Format

When you export a workout, CurlBro generates a human-readable text representation. Each exercise appears on its own line with sets, reps, and rest period:

Workout: Push Day
Split: push

Barbell Bench Press  4x7  @180s rest
Incline Dumbbell Press  3x10  @120s rest
Dumbbell Shoulder Press  3x10  @120s rest
Cable Lateral Raise  3x15  @60s rest
Cable Flye  3x12  @60s rest
Tricep Pushdown  3x12  @60s rest
Overhead Tricep Extension  3x12  @60s rest
Face Pull  3x15  @45s rest

If you have the "Include tips" export setting enabled, beginner tips and form cues are appended below each exercise for reference.

Import Format

You can import workouts by pasting text in the same format. CurlBro's parser is flexible — it handles minor variations in formatting. The core grammar for each exercise line is:

Exercise Name  SETSxREPS  @RESTs rest

The parser matches exercise names against the database using fuzzy search, so exact names are not required. If a match cannot be found, the exercise is skipped with a warning message telling you which line failed.

AI-Generated Workouts

CurlBro publishes an LLM-friendly exercise catalog at /exercises.json and detailed import instructions at /llms.txt. These files are designed to be consumed by AI assistants (ChatGPT, Claude, etc.) to generate workouts in CurlBro's import format. The workflow:

1. Give your AI assistant the CurlBro exercise catalog URL or paste the contents of llms.txt.
2. Describe the workout you want (e.g., "Create a push day focusing on upper chest with 30-minute time constraint").
3. The AI generates a workout in CurlBro's text format.
4. Paste the generated text into CurlBro's import panel.
5. CurlBro parses the text, matches exercises against the database, and creates a workout ready to edit or start.

Sharing with Friends

The export text is designed to be easily sharable. Copy it to your clipboard and send it via text message, email, or social media. Your friend can paste it into their CurlBro import panel to load the same workout. Since CurlBro is a free web app with no accounts, there are no sharing restrictions — anyone can import any workout text.

Settings Reference

The Settings tab lets you configure CurlBro's defaults to match your training style. All settings persist in your browser's local storage.

Training Goal

Choose between Strength, Hypertrophy, or Endurance. This affects the default rep ranges when adding exercises. Strength uses lower rep ranges (e.g., 1–5), hypertrophy uses moderate ranges (e.g., 6–12), and endurance uses higher ranges (e.g., 12–15+). Based on Schoenfeld's 2017 meta-analysis on rep range dose-response.

Default Sets — Compound Exercises

The default number of sets pre-filled when you add a compound exercise. Default: 4 sets. Adjust based on your training volume preferences and recovery capacity.

Default Sets — Isolation Exercises

The default number of sets pre-filled when you add an isolation exercise. Default: 3 sets. Isolations typically need fewer sets than compounds for adequate stimulus.

Rest Timer — Compound Exercises

Default rest period in seconds for compound movements. Default: 120 seconds. NSCA guidelines recommend 2–5 minutes for strength-focused compound work and 1–2 minutes for hypertrophy.

Rest Timer — Isolation Exercises

Default rest period in seconds for isolation movements. Default: 60 seconds. Shorter rest periods for isolations maintain metabolic stress, which is one of the three primary mechanisms of hypertrophy (Schoenfeld 2010).

Include Tips in Export

When enabled, exported workout text includes beginner form tips and cues below each exercise. Useful when sharing workouts with less experienced training partners. Default: enabled.

Reset Settings

Restores all settings to their default values without affecting your saved workouts or logs.

Clear All Data

Permanently deletes all saved workouts and workout logs from your browser. This action cannot be undone. Pre-built templates are not affected since they are bundled with the app.

Privacy & Data

What CurlBro Stores

• Your saved workouts and their exercise configurations
• Workout log entries (completed sessions with set data)
• App settings (training goal, default sets, rest timer preferences)
• Body state data (muscle soreness levels and recent activities)
• Cookie consent preference

What CurlBro Does Not Store

• No personal information (name, email, age, etc.)
• No authentication credentials or account data
• No data on any server or cloud service
• No tracking data beyond anonymous Google Analytics (with explicit consent)

Analytics and Cookies

CurlBro uses Google Analytics to understand aggregate usage patterns (which features are popular, how long sessions last, etc.). Analytics data collection is disabled by default and only activated if you explicitly accept cookies via the consent banner. This implementation follows Google Consent Mode v2, which ensures that no analytics or advertising data is collected or stored until consent is granted.

You can review and change your cookie preferences at any time from the Settings tab under "Manage Cookies." Revoking consent immediately stops all analytics data collection.

Data Portability

Since all data is stored locally, you control it completely. Export your workouts as text to back them up externally. If you clear your browser's localStorage or switch devices, your data will not carry over — export any workouts you want to keep before clearing browser data.

Tips & Best Practices

Make the most of CurlBro with these evidence-based training tips. Each recommendation is grounded in the same scientific literature that powers CurlBro's programming tools.