WATTS PER KILO

Watts per kilo (W/kg) is your power output divided by your body weight. On any gradient steep enough that gravity dominates — roughly 3% and up — your climbing speed is set almost entirely by W/kg, because you are mostly lifting mass rather than fighting air.

Most of the time "W/kg" means threshold W/kg: FTP over body weight. But the same maths applies at any duration, and the picture is more interesting when you look at several:

Note how compressed the top is: the gap between a strong club rider at 4.0 W/kg and a professional at 5.8 is only about 45% — and yet on a mountain pass it is the difference between forty minutes and twenty-eight.

Add watts (the good route)

• Build volume in zone 2 — the aerobic base that everything else sits on.
• Add two quality sessions a week: sweet spot or threshold intervals early in a block, VO2 max work closer to your goal event.
• Be consistent for months, not heroic for a fortnight. Threshold responds to accumulated weeks.
• Fuel your sessions properly. Under-fuelled intervals are just expensive fatigue.

Lose mass (the careful route)

• 0.25-0.5kg a week at most, and never in the middle of a hard training block.
• Keep protein high — around 1.6-2g per kilo — so what you lose is not muscle.
• Stop before it hurts your training. A rider 2kg lighter and 15W weaker is slower uphill, not faster.
• Be honest about whether this is the right lever at all. Most riders have far more watts available than kilos.

On flat roads, in time trials, in crosswinds and in a bunch sprint, raw watts and aerodynamics win. Big riders dominate flat racing for exactly this reason. If your local riding is pancake flat, obsessing over power to weight is chasing the wrong number — total watts and a decent position will do far more for you.