We Track 20 Muscles So You Don't Overtrain

Bi-exponential recovery. Research-grade fatigue modeling. Every muscle has a status. The AI won't serve an exercise if the target muscles aren't ready.

Muscle Recovery Status Updated 2min ago
Chest
55%
Back
65%
Quads
40%
Glutes
75%
Shoulders
45%
Hamstrings
80%
Triceps
60%
Biceps
85%
Core
50%
Calves
70%

Fast + Slow Recovery

Real muscle recovery isn't a simple countdown. It follows a bi-exponential curve with two distinct phases:

Fast component (60%) — Metabolic recovery. Glycogen replenishment, lactate clearance, inflammation subsiding. 8-hour half-life for all muscles.

Slow component (40%) — Structural recovery. Muscle fiber repair, protein synthesis. Half-life depends on muscle size: large muscles 42h, medium 30h, small 20h.

Recovery After Workout
0h12h24h36h48h100%75%50%25%0%Total RecoveryFast (metabolic)Slow (structural)Time After Workout

5 Recovery States

Every muscle is classified into one of five states. The Ready zone (15-30%) is actually the sweet spot — research shows muscles respond best when slightly fatigued.

Fresh
Ready
Working
Fatigued
Overworked
Fresh
< 15%
Fully recovered. Ready to go hard.
Ready
15-30%
Optimal zone. Science says this is the sweet spot.
Working
30-50%
Active recovery range. Still trainable.
Fatigued
50-70%
Needs rest. AI deprioritizes these muscles.
Overworked
> 70%
Avoid training. Risk of overuse injury.

Intra-Session Muscle Recovery

Within a single gaming session, Killogram also tracks phosphocreatine (PC) resynthesis — the energy system that powers short bursts of effort.

If you just did heavy push-ups and die again 30 seconds later, your chest isn't ready. Instead of serving more push work, the AI inserts a recovery filler — a mobility stretch, core hold, or light cardio — to give those muscles time.

Minimum recovery: 60 seconds. Failed the last set? Bonus +30 seconds.

PC Recovery Timeline
0s
Just exercised
30s
Half recovered
60s
Ready (minimum)
90s
Fully recovered
Recovery filler examples: Child's Pose, Cat-Cow Stretch, Dead Bug, Jumping Jacks

Muscle Size Matters

Large muscles (chest, back, quads, glutes) take longer to recover structurally than small muscles (calves, forearms, abs). Killogram models this with size-dependent slow half-lives:

Large Muscles 42h half-life
Chest, Back, Quads, Glutes
Medium Muscles 30h half-life
Shoulders, Hamstrings, Triceps, Core
Small Muscles 20h half-life
Calves, Forearms, Abs, Hip Flexors

Built on Peer-Reviewed Research

Killogram's bi-exponential recovery model, size-dependent half-lives, and fatigue thresholds are derived from published exercise science research. We read the papers so you don't have to.

  • Nosaka & Clarkson (1996) — Muscle damage and recovery after eccentric exercise
  • Byrne, Twist & Eston (2004) — Neuromuscular function after exercise-induced muscle damage
  • Schoenfeld (2010) — The mechanisms of muscle hypertrophy and their application to resistance training

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