Firth

An easy aerobic session that builds the engine everything else sits on, and lets you absorb the hard days.

Grade: Recovery · Zone 2 · Aerobic (25 min)

The workout

• Primer: 5 min easy walk → very light jog or spin
• Base: 25 min very easy @ 60% HRmax · the gentlest session of the whole cycle
• Breathe: 10 min slow nasal breathing · 4 s in, 6 s out, flat on your back
• Flow: 10 min soft stretching · whatever still feels tight

Why we programme this

Zone 2 is the least glamorous and most important work a hybrid athlete does. Held at a truly easy intensity it grows mitochondria, sharpens fat oxidation and thickens the aerobic base that every threshold run, sled and carry draws from. It also clears fatigue rather than adding to it, so tomorrow's hard session lands on fresh legs. Skip it and your ceiling stops rising no matter how many hard days you stack.