How to Use

BringHIIT — Randomized, Science-Backed Workouts

BringHIIT is an app that takes the thinking out of training. It runs in your browser on any device, and with one tap it generates a complete workout tailored to your equipment, your time, and your energy level. Every session is different. You just show up and execute.

You tell the app what you have and what exercises you like. It builds randomized circuits combining strength, conditioning, and cardio—with automatic weight progression, rest timers, and intensity targets. No planning. No decisions. Just effort.

What You'll Achieve

Stick with this system for 12-24 months and you can realistically expect:

Domain Where You'll Land What That Means
Strength Top 10-20% of adults Carry all the groceries in one trip. Help friends move without faking a back injury. Open every jar. Feel capable and powerful in your body.
Body Composition Top 10-20% Look great naked. Clothes fit better. Visible muscle definition. The mirror becomes your friend.
Cardiovascular Fitness Top 15-25% Take the stairs without thinking. Play with your kids without gasping. Hike without being the slow one. Sustained energy all day.
Work Capacity Top 15-25% Shovel the driveway, move furniture, handle physical labor—then do it again tomorrow. Your body just handles things.
Metabolic Health Significantly improved Lower resting heart rate (your heart works less for the same output). Healthy blood pressure. Better insulin sensitivity, favorable cholesterol. Reduced risk of the diseases that kill most people.

These aren't elite athlete levels—they're realistic outcomes for consistent training. Compared to the general population (including all the people who don't exercise), you'll be notably fit, strong, and healthy. You'll move through the world differently. Physical tasks become easy. You'll have energy left over at the end of the day.

Fine print: These results assume your diet is at least somewhat reasonable. You can't out-train a daily habit of fast food, candy, and sugary soda. You don't need to be perfect—just don't actively work against yourself.

What this system won't produce
  • Elite powerlifting totals
  • Competitive bodybuilding physiques
  • Marathon-level endurance
  • Sport-specific peak performance

If those are your goals, you need specialized programming. This system optimizes for broad, sustainable fitness—being strong, conditioned, lean, and healthy for life.

You Just Focus on Effort

Here's what makes this different: you don't need to understand programming, periodization, or progression schemes. You don't need to plan anything. You don't need to decide what to do today.

The app handles:

You just show up and try hard. That's it.

When you consistently hit your targets, weights go up automatically—to increments that match your actual equipment. No spreadsheets. No calculations. No "what percentage of my max should I use today?" No decision fatigue.

This matters more than most people realize. Decision fatigue kills workout consistency. "What should I do today?" becomes "maybe I'll figure it out tomorrow." With BringHIIT, you hit Generate and go. The thinking is done.

For beginners especially: you don't need to learn programming theory before you can train effectively. Just execute what the app gives you, push yourself appropriately, and the system handles your progression over weeks and months. Focus on learning the movements and giving honest effort—that's enough.

How It Works

1. Build Your Exercise Pool

Add the exercises you want to do, organized into categories you define. Only have dumbbells? Only add dumbbell exercises. Can't overhead press? Don't include it. Your pool, your rules.

2. Configure Your Equipment

Tell the app exactly what you have: specific dumbbell weights, barbell setup, kettlebells, treadmill limits, conditioning equipment. Progression respects your actual gear—no theoretical increments you can't load.

3. Generate a Workout

Choose how many exercises per category, hit Generate, and get a complete session: exercise selection, rep targets, intensity assignments (RIR for strength, RPE for conditioning), calculated weights, round structure, and rest periods. Session duration is randomized within your configured range—even your workout length stays fresh. See time estimates before you start. Save your favorite configurations as presets for one-tap access.

4. Execute with Guidance

Built-in rest timers with audio cues. One-tap rep logging. Between-round celebrations. Optional treadmill finisher absorbs remaining time so sessions end exactly when planned—or skip it if you prefer.

5. Progress Automatically

The app tracks every set. Hit your rep targets consistently? Weight increases automatically to the next increment you actually have. You focus on effort—the algorithm handles progression math.

See the full feature breakdown

Exercise Configuration

  • Completely custom categories (push/pull/legs, upper/lower, equipment-based—whatever fits your philosophy)
  • Accessory categories with smart rotation: Mark categories as "accessories" (like biceps, triceps, shoulders, abs). Instead of training all accessories every workout, choose how many to include per session—the system rotates through them so all get trained over time. Perfect for managing workout length while ensuring balanced accessory coverage.
  • Bodyweight toggle for equipment-free exercises
  • Per-exercise progression thresholds (heavy compounds at 6 reps, isolation at 12, etc.)

Equipment Settings

  • Specific kettlebell weights you own
  • Specific dumbbell weights (or ranges with increments)
  • Barbell max load and plate increments
  • Treadmill incline/speed limits
  • Metric or imperial units
  • Multi-equipment exercises: Link one exercise to multiple equipment types—a goblet squat can use kettlebells OR dumbbells. The system merges available weights so you get smaller progression jumps without buying more gear.

Intensity Ranges (All Adjustable)

Parameter Default Notes
Strength RIR 1-3 Hard effort, never to absolute failure
Conditioning RPE 7-10 Scaled to your capacity
Conditioning duration 20-120 sec Per piece
Running duration 60-180 sec Or toggle off entirely
Rest between exercises 20-40 sec Short—you're switching muscle groups
Rest between rounds 60-120 sec Full recovery
Session duration 45-60 min Randomized within your range

Smart Features

  • Workout presets: Save your favorite configurations (exercise counts per category, accessories per workout, treadmill setting, tired mode) and load them with one tap. Up to 10 presets.
  • Duration estimation: Warns if your configuration exceeds target time
  • Optional walking substitution: Auto-replace running with incline walking on heavy leg days (configurable threshold)
  • Pre-workout setup screen: See everything before starting; adjust weights if needed
  • Tired Mode: Bad sleep? Reduce intensity, cap volume, extend rest—still train (all Tired Mode adjustments are configurable)

Tracking

  • Pre-workout: energy level, sleep quality (suggests Tired Mode if both low)
  • Post-workout: notes, session rating
  • Dashboard: days since last workout, streaks, weekly volume by category

Your Data

  • Minimal account (username only; email for 2FA verification, not stored)
  • No IP logging, no tracking, no behavioral data
  • Data stored in a Norwegian data center, protected by some of the strictest privacy laws in the world
  • Full export (CSV/JSON): workout history, exercises, configuration
  • Import configurations for backup restoration or sharing

Smart Randomization (Not Chaos)

The workouts are randomized—but not randomly thrown together. There's an important distinction:

Random where it creates novelty:

Structured where it matters:

Think of it like a chef who knows the fundamentals but improvises the details. The meal is always balanced and nourishing—but never boring.

Over weeks and months, this creates natural periodization. Some sessions land harder (RIR 1 across the board, longer conditioning pieces). Some lighter (RIR 3, shorter bursts). You can't predict it, which keeps you engaged—but the system ensures everything adds up to balanced, progressive training.

You're not following randomness. You're following a program that randomizes what can be randomized while protecting what must be consistent.

Why Randomization Works

The best workout is the one you actually do.

Research shows approximately 50% of people who start exercise programs quit within six months. The failure isn't physical—it's psychological. Boredom, monotony, and decision fatigue kill consistency.

Randomization solves this:

You might think a "random" workout can't be optimal. Here's the thing: over weeks and months, it doesn't matter. Your body adapts to cumulative stress, not any single session. A suboptimal workout you complete beats a perfect workout you skip.

The research on variety and adherence

Sylvester et al. (2016) conducted an RCT with 121 previously inactive adults and found high-variety training produced significantly greater adherence than low-variety alternatives (p = 0.02). The relationship was mediated by perceived variety—people who felt they were doing varied training stuck with it longer.

Dominski et al. (2021) systematically reviewed 34 studies with 7,000+ participants in high-intensity functional training and found high intrinsic motivation driven by enjoyment, challenge, and novelty. Participants reported exercising because it was genuinely engaging—not because they felt obligated.

Why Mixed-Modal Training Works

Mixed-modal training combines strength, conditioning, and cardio in the same session. You might have heard this causes an "interference effect"—that combining modalities compromises both.

Modern research disagrees.

A 2022 meta-analysis of 43 studies found no significant difference in strength or muscle gains between concurrent training and strength-only training. You can build strength, improve conditioning, and enhance body composition in the same program without meaningful compromise.

The research on concurrent training

For years, trainers warned that combining strength and endurance training would compromise both. This belief stemmed from a 1980 study using extreme protocols (11 training sessions per week).

Schumann et al. (2022) analyzed 43 studies with over 1,000 subjects and found no significant difference in maximal strength (SMD = -0.06, p = 0.45) or muscle growth (SMD = -0.01, p = 0.92) between concurrent training and strength-only training. Only explosive power showed modest interference (SMD = -0.28)—and even that disappeared when training sessions were separated by 3+ hours.

Wilson et al. (2012) analyzed 21 studies and confirmed that for recreational trainees, combining modalities produces excellent results across all domains. Running causes slightly more interference than cycling due to eccentric muscle damage, but practical effects are negligible for non-elite populations.

Why Autoregulation Works

Your strength fluctuates daily by up to ±18% based on sleep, stress, nutrition, and fatigue. A fixed program prescribing "80% of your max" ignores this reality.

This app uses autoregulation: intensity targets based on how you feel that day. RIR (Reps in Reserve) for strength movements, RPE (Rate of Perceived Exertion) for conditioning. Research shows this approach produces equal or better results than fixed percentages—with lower injury risk.

Understanding RIR and RPE

RIR (Reps In Reserve) — For Strength Exercises

Answers: "How many more reps could you have done with good form?"

RIR Meaning What It Actually Feels Like
3 Could do 3 more Solid effort. You're working, breathing harder, but clearly have more in the tank. Conversation is possible between sets.
2 Could do 2 more Genuinely challenging. The last rep required focus. You're glad to rack the weight, but you know two more were there.
1 Could do 1 more Hard. Really hard. The last rep was a grind. One more might be possible but it would be ugly and slow. You're relieved it's over.
0 Failure Cannot complete another rep with acceptable form. The bar isn't moving or your form has completely broken down.

A note for beginners: RIR takes practice to judge accurately. When you're new, everything feels hard, and RIR 3 might feel like near-failure. That's normal. Start conservative—if you think you're at RIR 2, you might actually have 3-4 reps left. As you gain experience, your self-assessment improves. The app's progression system is forgiving; it will adjust over time based on your logged performance.

How to use it: When the app shows "RIR 2" for bench press, do reps until you feel like two more quality reps would be possible—challenging but not desperate. If you stop at 8 reps, you should finish thinking "I could have gotten 10, but it would have been tough."

RPE (Rate of Perceived Exertion) — For Conditioning

A 1-10 scale measuring overall effort:

RPE Meaning Feel
6 Light Conversational, sustainable indefinitely
7 Moderate Short sentences, breathing elevated
8 Hard Few words only, breathing heavy
9 Very hard Can barely speak, approaching max sustainable
10 Maximum All-out, cannot maintain

Why conditioning uses RPE: Conditioning exercises (bike, rower, burpees) don't have discrete reps—you're working for time. RPE captures subjective intensity of sustained effort.

The research on autoregulation

Hickmott et al. (2022) conducted a systematic review and meta-analysis finding that autoregulated training produced a near-significant advantage over fixed percentages (SMD = 0.21, p = 0.09), with subjective methods (RIR/RPE) showing a small effect favoring autoregulation (SMD = 0.30) in interventions lasting 8+ weeks.

Zourdos et al. (2016) validated the RIR-based scale, showing experienced lifters accurately gauge effort (r = -0.88 between velocity and RPE), while novices improve with practice.

Tired Mode

Bad sleep. Stressful week. Feeling run down. Rather than skip (breaking your habit), Tired Mode lets you train appropriately:

What Changes Normal Tired Mode
Strength intensity Your RIR range +1 RIR (easier)
Conditioning intensity Your RPE range -1 RPE (easier)
Maximum rounds Your range Capped lower
Rest periods Your range Extended
Running Normal Incline walking

All Tired Mode adjustments are configurable—set your own thresholds for how much the system backs off.

You still train. You maintain the habit. You recover. You come back stronger.

FAQ

I'm a complete beginner. Is this for me?

Yes—with one caveat. You should learn basic movement patterns first (how to squat, hinge, press, pull with decent form). The app assumes you know how to perform the exercises you add to your pool. If you're brand new, consider a few sessions with a trainer or following beginner tutorials for fundamental movements, then use this app to program your ongoing training.

The good news: you don't need to understand programming, periodization, or progression theory. Just execute what the app gives you and focus on honest effort. The system handles the complexity.

I'm an experienced lifter. Will this challenge me?

Yes. The intensity ranges (RIR 1-3 for strength, RPE 7-10 for conditioning) are appropriate for any level. Experienced lifters will simply use heavier weights. The autoregulation means the system scales to your capacity. You can also tighten the ranges (e.g., RIR 1-2 only) for more aggressive programming.

How is this different from CrossFit?

Similar philosophy (mixed-modal, constantly varied), different execution. This app gives you individual programming based on your equipment and preferences—not class-based workouts designed for groups. There's no competitive element, no prescribed WODs, and intensity is autoregulated rather than "as fast as possible." You also control exactly which exercises appear.

Won't random workouts lead to muscle imbalances?

Over time, no. You control the category structure and exercise counts per workout. If you include 2 push exercises and 2 pull exercises per session, you'll accumulate balanced volume across weeks—even though individual sessions vary. The randomization is constrained by your configuration.

What if I want to focus on specific goals?

Adjust your configuration. Want more leg work? Add more leg exercises per round. Want minimal conditioning? Set conditioning count to 0-1. Want pure strength? Extend rest periods, reduce conditioning, tighten RIR to 2-3. The system is flexible—you shape it to your priorities.

How do accessory categories and rotation work?

Accessory categories (like biceps, triceps, shoulders, abs) work differently from main categories. Instead of including all accessories in every workout—which would make sessions too long—you choose how many accessories to include per workout, and the system rotates through them.

Example: You have 4 accessory categories (Biceps, Triceps, Shoulders, Abs). Setting "Per workout: 2" means:

  • Workout 1: Biceps + Triceps
  • Workout 2: Triceps + Shoulders
  • Workout 3: Shoulders + Abs
  • Workout 4: Abs + Biceps
  • ...and the cycle continues

Why this matters:

  • Shorter workouts: Don't need to hit every accessory every session
  • Complete coverage: All accessories get trained over a few workouts
  • Fresh stimulus: Each workout has a slightly different accessory focus
  • Flexibility: Set 0 for no accessories (pure compound focus), or match your accessory count for all-inclusive sessions

The "Accessory Focus" shown on your workout preview tells you which accessories are included that day. You can save different configurations as presets—maybe "Quick" with 2 accessories and "Full" with all of them.

How long are the workouts?

You set your target duration range (default 45-60 minutes). Each workout randomly selects a target within that range for variety. The app estimates time based on your configuration and warns if you'll exceed it. The optional treadmill finisher absorbs remaining time, so sessions end exactly when planned.

Do I need a full gym?

No. Add only exercises you can do with your equipment. Home gym with just dumbbells and a pull-up bar? Add those exercises. Full commercial gym? Add whatever you want. The app adapts to your constraints.

Can one exercise use different equipment types?

Yes—for exercises where the equipment is interchangeable. A goblet squat works identically with a kettlebell or dumbbell. Lunges, Romanian deadlifts, floor presses, farmer's carries—all can use either.

Why this matters: Equipment often has big weight jumps. Kettlebells might go 16→20kg (a 25% increase). But if you also have an 18kg dumbbell, the system uses it as a stepping stone. Smoother progression without buying more gear.

This is especially useful for home gyms with mixed collections. Your random assortment of kettlebells and dumbbells becomes a cohesive weight ladder.

What about rest days and recovery?

The app doesn't prescribe training frequency—that's up to you. Most people do well with 3-5 sessions per week with rest days between. The dashboard shows "days since last workout" to help you stay accountable. If you're consistently fatigued, train less frequently or use Tired Mode more often.

Can I skip exercises I don't like?

Yes—don't add them to your pool. You only see exercises you've chosen to include. Hate burpees? Don't add burpees. The system never forces exercises on you.

How does progression work exactly?

Each exercise has two configurable thresholds: a rep threshold (the average reps you need to hit) and a sessions to progress count (how many consecutive successful sessions before weight increases). When you meet the rep threshold for the required number of sessions, the weight increases to your next available increment.

Key point: progression always respects your actual equipment. If you have dumbbells at 10kg, 12.5kg, and 15kg, you progress through those exact weights—not theoretical 1kg jumps you can't load. The system knows what you have and works within those constraints.

Heavy compounds like deadlifts might use a threshold of 6; isolation work like curls might use 12. You configure each exercise based on how you want to train it.

Is my data private?

Yes. We store only your username. Email is used for 2FA verification during signup and isn't retained. No IP logging, no tracking, no behavioral data collection.

Your data is stored in a Norwegian data center, protected by some of the strictest privacy laws in the world (GDPR plus additional Norwegian regulations).

You can export everything (workouts, exercises, configuration) anytime.

Training Tips

Pacing conditioning pieces (the ramp-up principle)

Your aerobic system needs time to activate. When you start a conditioning piece, your body relies on anaerobic energy—which feels powerful but runs out fast.

The trap: Going all-out feels easy at first. But you're accumulating oxygen debt. Around 40-60 seconds, you hit a wall.

For short pieces (20-40 seconds): These are genuinely anaerobic. Go hard from the start.

For longer pieces (60-120 seconds): Pace yourself.

  1. First 15 seconds: Start 1-2 RPE below target (feels too easy)
  2. Middle: Build as breathing settles
  3. Final third: At or slightly above target RPE

For a 90-second piece at RPE 8:

  • 0-20s: RPE 6-7
  • 20-60s: Build to RPE 8
  • 60-90s: Hold or push above

This isn't sandbagging—you'll maintain higher average output and recover faster for the next round.

Why short rest between exercises is fine

Research shows 3-minute rest produces better strength gains than 1-minute rest—but that assumes you're resting between sets of the same exercise.

In a circuit (push → legs → pull → conditioning), each muscle group recovers for 3-5+ minutes while you work other areas. The 20-40 seconds between exercises is just transition time. Your muscles get plenty of recovery.

Why we cap at RIR 1 (never to failure)

Research shows similar muscle-building outcomes when stopping 1-3 reps short of failure. Benefits of avoiding failure:

  • Reduced injury risk on compound movements
  • Faster recovery between sessions
  • Lower nervous system fatigue
  • Ability to train more frequently

Save "grinding" reps for occasional testing, not regular training.

Research References

Full citations

Concurrent Training & Interference:

  • Schumann, M., Feuerbacher, J.F., Sünkeler, M., Freitag, N., Rønnestad, B.R., Doma, K., & Lundberg, T.R. (2022). Compatibility of concurrent aerobic and strength training for skeletal muscle size and function: An updated systematic review and meta-analysis. Sports Medicine, 52(3), 601-612. https://doi.org/10.1007/s40279-021-01587-7
  • Wilson, J.M., Marin, P.J., Rhea, M.R., Wilson, S.M.C., Loenneke, J.P., & Anderson, J.C. (2012). Concurrent training: A meta-analysis examining interference of aerobic and resistance exercises. Journal of Strength and Conditioning Research, 26(8), 2293-2307. https://doi.org/10.1519/JSC.0b013e31823a3e2d

Exercise Variety & Adherence:

  • Sylvester, B.D., Standage, M., McEwan, D., Wolf, S.A., Lubans, D.R., Eather, N., Kaulius, M., Ruissen, G.R., Crocker, P.R.E., Zumbo, B.D., & Beauchamp, M.R. (2016). Variety support and exercise adherence behavior: Experimental and mediating effects. Journal of Behavioral Medicine, 39(2), 214-224. https://doi.org/10.1007/s10865-015-9688-4
  • Dominski, F.H., Serafim, T.T., Siqueira, T.C., & Andrade, A. (2021). Psychological variables of CrossFit participants: A systematic review. Sport Sciences for Health, 17(1), 21-41. https://doi.org/10.1007/s11332-020-00685-9

Autoregulation & RIR/RPE:

  • Hickmott, L.M., Chilibeck, P.D., Shaw, K.A., & Butcher, S.J. (2022). The effect of load and volume autoregulation on muscular strength and hypertrophy: A systematic review and meta-analysis. Sports Medicine - Open, 8(1), 9. https://doi.org/10.1186/s40798-021-00404-9
  • Zourdos, M.C., Klemp, A., Dolan, C., Quiles, J.M., Schau, K.A., Jo, E., Helms, E., Esgro, B., Duncan, S., Garcia Merino, S., & Blanco, R. (2016). Novel resistance training-specific rating of perceived exertion scale measuring repetitions in reserve. Journal of Strength and Conditioning Research, 30(1), 267-275. https://doi.org/10.1519/JSC.0000000000001049

Rest Periods:

  • Schoenfeld, B.J., Pope, Z.K., Benik, F.M., Hester, G.M., Sellers, J., Nooner, J.L., Schnaiter, J.A., Bond-Williams, K.E., Carter, A.S., Ross, C.L., Just, B.L., Henselmans, M., & Krieger, J.W. (2016). Longer interset rest periods enhance muscle strength and hypertrophy in resistance-trained men. Journal of Strength and Conditioning Research, 30(7), 1805-1812. https://doi.org/10.1519/JSC.0000000000001272

The best program is the one you'll actually do. BringHIIT makes that easy—by making every session genuinely interesting.