Energy Systems 101: How Your Body Actually Fuels Strength, Speed, and Endurance

Ever wonder why you gas out during a metcon but can lift heavy with no problem?
Or why a sprinter needs a different type of fitness than a marathoner?
It’s all about energy systems.
And if you want to be a complete athlete — strong, fast, durable — you need to train all three.

The 3 Energy Systems (Simple Breakdown)

1. ATP-PC System (Alactic)

• Duration: 0–10 seconds

• Fuel Source: Stored ATP and phosphocreatine

• Use: Heavy lifts, sprints, jumps, max-effort efforts

• Training: Heavy 1–5 rep lifts, short sprints, explosive work

👉 Think deadlifting 500 pounds — pure power.

2. Glycolytic System (Lactic)

• Duration: 30 seconds – 2 minutes

• Fuel Source: Stored glycogen (carbs)

• Use: Hard conditioning, repeated sprint efforts, moderate reps

• Training: Metcons, intervals, hard circuits

👉 Think a 400m sprint — painful but powerful.

3. Aerobic System (Oxidative)

• Duration: 2 minutes – forever

• Fuel Source: Oxygen and fat stores

• Use: Long steady efforts, recovery between sets, life activities

• Training: Zone 2 cardio, longer intervals

👉 Think marathon — steady grind energy.

Why You Need All Three

✅ Strong ATP-PC = lift heavy, sprint fast
✅ Strong Glycolytic = dominate hard sessions, recover faster
✅ Strong Aerobic = outlast the competition, recover day to day

Athletes who ignore one system have glaring holes in performance.

How HTC 365 Training Covers This

• Heavy days for power and ATP-PC system

• Interval/metcon days for glycolytic power

• Zone 2 and aerobic conditioning days for endurance and fat burn

Balanced energy = complete performance.

Action Steps for This Week:

✅ Lift heavy (3–5 reps) 1–2x a week.
✅ Add 1 hard conditioning session (20–30 mins).
✅ Add 1–2 aerobic base sessions (Zone 2 cardio).

Cover all 3 — even lightly — every week.

In HTC 365, we don't just build muscles — we build engines.
Start your free 7-day trial today and train all three energy systems the right way. Join HTC 365