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ResourcesGuides1RM CalculatorTDEE CalculatorMacro Calculator (Lifters & Runners)ACWR CalculatorAbout

Training library

Guides for lifters who run.

Plain-English explanations of the training science behind Mass in Motion: how to manage lifting and running load together, read your recovery, dial in pace, and set the numbers that drive your program. No fluff, no AI-written filler.

Hybrid

Hybrid Athlete Training Plan: Weekly Lift and Run Schedules

Copyable weekly schedules for lifting and running together: 3 full-body lifts with 2 runs, an upper/lower split with 3 runs, or 4 lifts with 4-5 runs, plus the sequencing and load rules behind them.

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Hybrid

Concurrent Training

Can you build muscle and run at the same time? What the interference effect really means and how to program both so each keeps progressing.

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Hybrid

Lifting & Running the Same Day

Which to do first, how many hours to leave between them, and why order and spacing change your results when you train both in one day.

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Strength

RPE & RIR

Autoregulate your lifting to how strong you actually are on the day: how the scales work, how they relate to percentages, and why it beats fixed numbers.

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Strength

Conjugate-Style Training

Rotate max-effort, dynamic-effort, and repetition work to get stronger without grinding limit sets every week, and why it suits athletes who run.

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Running

Running for Lifters: How to Start Without Losing Strength

How lifters can start running without sacrificing hard-earned muscle or squat strength: run frequency, Zone 2 vs intervals, leg day spacing, and gradual mileage progression.

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Running

Zone 2 Running for Lifters

How easy Zone 2 running should feel, how often lifters should do it, where to place easy runs around leg training, and when to add faster work.

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Running

Running Pace Zones

Why easy runs should make up most of your weekly volume, how race-predicted pace targets are set, and what each training zone is actually for.

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Running

Marathon Training for Lifters

Build the miles without surrendering your strength: mileage ramps, protecting your lifting, and coordinating the taper.

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Recovery

What Is a Good HRV for Athletes?

Why there is no universal good HRV number, how to read your own baseline, and how HRV combines with resting heart rate, sleep, and training load into a daily recovery score.

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Recovery

Why Is My HRV Low? Training, Sleep, Stress and Illness

Why your heart rate variability (HRV) is low: training load, sleep loss, psychological stress, dehydration, alcohol, illness, and how to adjust your training.

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Recovery

Should You Change Your Workout Based on Your Recovery Score?

How to interpret low wearable recovery scores, when to train as planned, when to modify volume, and how to combine HRV with warm-up feedback.

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Recovery

ACWR & Managing Load

The acute-to-chronic workload ratio explains why athletes get hurt when they spike volume too fast, and how to ramp safely across lifting and running.

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Recovery

How to Use the ACWR Calculator

A step-by-step walkthrough of the free ACWR calculator: what to enter for each day, how the effort-times-minutes load works, and how to read your ratio.

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Recovery

Deload Weeks

When to take a planned easy week, what to actually reduce, and how backing off at the right time lets your fitness finally surface.

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Recovery

Sleep Hygiene & Circadian Rhythm

Science-backed strategies to optimize sleep quality: circadian light timing, ideal bedroom temperature, pre-bed heat therapy, nutritional timing, and sleep-supporting supplements.

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Recovery

Macros for Hybrid Athletes: Protein, Carbs & Fat

A practical macro guide for athletes who lift and run: protein targets, when carbs matter most, how to use fat, and how to scale intake with training volume.

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Tools

1RM Calculator

Estimate your one-rep max from any set with the Epley formula, then read the training percentages behind max-effort, hypertrophy, and speed work.

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Tools

TDEE Calculator for Weight Loss, Maintenance & Muscle Gain

Find your Total Daily Energy Expenditure and a calorie target for fat loss, maintenance, or muscle gain, plus how steps and mileage change the number and how to adjust from your weekly weight trend.

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Tools

Macro Calculator for Lifters and Runners

Turn your calorie target into protein, carbohydrate, and fat targets with a training focus for hybrid athletes: strength, endurance, hybrid, fat loss, lean gain, or high-mileage fueling.

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Tools

ACWR Calculator

Calculate your acute-to-chronic workload ratio (ACWR) from your last 7 days of training to prevent overtraining and manage injury risk.

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Basics

What Is Mass in Motion?

The short version of what the app is, who it is for, and how lifting and running live in one adaptive system.

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Basics

How Mass in Motion Tracks Training Load

How the app keeps lifting load, running load, combined workload, recovery trends, and the demands of the next session in context.

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Basics

How It Works

How the app builds and adjusts your plan: the principles and guardrails behind it, and why it is algorithm-driven rather than AI-generated.

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One app for the lift and the run

Recovery-aware programming that plans your lifting and running together. Join the update list for launch news and founder pricing.

Want to train on it now? Beta testers get the build before launch. Four questions, about thirty seconds.

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