Reading the Muscle Heatmap: spotting imbalances before they become injuries
Most intermediate lifters think their training is balanced. The Muscle Heatmap usually disagrees, and it has the effective volume data to prove it.
Training science, practical tips, and Intrvl product updates that keep your sessions honest and performance-focused.
Most intermediate lifters think their training is balanced. The Muscle Heatmap usually disagrees, and it has the effective volume data to prove it.
You're already holding your phone between every set. A dedicated countdown turns that screen from your biggest gym distraction into a focus anchor — and puts your timer and your log in one place.
Most lifters are resting for the wrong duration and calling it intuition. The research prescribes specific windows based on training goal, and the differences are not marginal.
You logged 20 sets for chest this week. The hypertrophy research says maybe 11 of them counted. Here's how to tell the difference and audit your real weekly volume.
Intrvl 2.9 ships a refreshed neon glass UI, expanded Activity Timers, goal-aware Muscle Breakdown, a new Goals priority screen, and Safety Snapshots for local backups. Plus Weight Book layout and stability fixes.
Volume Analytics is now a dedicated screen. Persistent session snapshots make every calculation faster. History Export v1.1 ships structured volume data for coach workflows. Plus updated pricing — $39.99/year or $79.99 lifetime.
Thirty seconds per set feels like friction. Over six months it becomes the only complete record of what you actually did — and the only way to know if your training is working.
A volume analytics drill-down, a simplified main menu, and an updated history export that includes volume window comparisons for coaches.
Without data, you can't distinguish between working harder and getting stronger. Here's why guessing about progression keeps you stuck.
Share training data with your coach. Build programs on the web. Import and export custom exercises. Plus a new analytics dashboard, muscle group filters, and timer fixes.
Most AI fitness apps give you generic programs. ChatGPT and Claude can generate programs tailored to your exact goals. You just need the right format.
Most fitness apps try to do everything. Intrvl does exactly two things—time intervals with precision, track weights with speed. Here's why less is more.
Training programs can now specify warm-up sets and failure targets. Plus navigation improvements and a premium access bug fix.
Stop scrolling between sets. Intrvl captures complete workout data in seconds, keeping your phone down and your focus on lifting.
Mark warm-up and failure sets directly in your JSON programs. Your analytics stay accurate from the first import.
Interval workouts now save to your training history, the dashboard shows your habits more clearly, and the timer has a new visual design. Plus a free trial and better iCloud protection prompts.
Paper workout logs enforce focus and simplicity. Here's what they get right—and where they leave gains on the table.
165,400kg moved, 597 sets logged, 16 failure sets. Here's what Strain Score, Effective Volume, and Muscle Heatmap show about training deliberately instead of accidentally.
Discover why the original interval set timer is still a foundational part of our workout timer app, and how it evolved into an integrated gym rest timer inside our weightlifting tracker.
Accurate to the second, even if you background the app. Here's how we designed a timer you can trust.
Short rests can sabotage strength and hypertrophy. The research and how to apply it in your sessions.
Simple tweaks that keep rests accurate and workouts flowing — alerts, Live Activities, and more.