The Boston Marathon course

Hopkinton, and the steepest drop of the whole day. You will feel fast on East Main Street because you are falling downhill in a crowd, and the bill for that comes due in Newton.

East Main gives way to West Union Street and the road keeps dropping. Sit in the pack, let the field carry you, and refuse to pass anybody this early.

More West Union, more descent, and the runners around you finally sort into something like your pace. An honest effort should still feel almost too easy here.

Union Street toward Ashland, net downhill again, but a 44 foot rise starts inside this mile and runs on past the marker. Expect the grade to change under your feet before you are done with it.

Waverly Street, and the first mile of the day that ends higher than it began. It is a small thing, easy to overreact to, worth no more than a slight shortening of stride.

Gentle downhill running on Waverly. Nothing here asks anything of you, which makes it the right place to take fluid and check your breathing.

Two train track crossings on Waverly in Framingham. Look down, quicken your feet over the rails, and pick the pace back up on the far side instead of through them.

Flat West Central Street. The road gives you no help and you need none: this is the quiet middle of Framingham and the pace should feel boring.

Barely a tilt downward as West Central runs on toward Natick. Another unremarkable mile, and unremarkable is exactly how to run it.

The road turns up for the first time in a long while, climbing into Natick. Hold your effort, let the pace slip a few seconds, and do not argue with the clock.

Central Street keeps rising through Natick. Two climbing miles back to back are the first real test of whether Hopkinton got the better of you.

The grade lets go and Central Street drops toward Wellesley. Take the free speed with light quick feet, not a longer stride.

Galen Stone Tower on Green Hall marks Wellesley College, and you will hear Wellesley well before you see it. The road is flat through here, so whatever the noise does to you, leave the effort where it was.

Halfway, off Central and onto Washington Street, with the elevation a wash. Whatever your split says, the race has not actually started yet.

Washington Street pulls upward through Wellesley. A modest climb, and the last polite one you get.

The biggest descent since the opening mile, dropping through Newton Lower Falls, and then the road tips up onto the Route 128 overpass. Quads that have been braking all morning will have an opinion about this one.

The overpass climb finishes and the road stays high. Set your posture and your attitude in this mile, because the Newton hills begin at the next marker.

Right turn at the Newton fire station and straight into Firehouse Hill on Commonwealth Avenue, 64 feet of it. Shorten the stride, lift the cadence, and let the pace go.

A genuine descent between hills on Commonwealth Avenue. Use it to breathe rather than to attack, because two more climbs are still in front of you.

The second Newton hill comes first, short and steep at 2.4 percent, and then Heartbreak begins before the mile is out. Measure everything here in effort, never in pace.

The rest of Heartbreak, then a long grind up past Boston College at the top. This is the hardest climbing mile on the course and getting through it upright is the entire objective.

Commonwealth Avenue falls away from Boston College and the running is downhill from here. It hurts more than it should, so let gravity do the work and keep your feet under your hips.

Chestnut Hill Avenue drops to Cleveland Circle and the turn onto Beacon Street, with trolley tracks to cross. Tired legs and steel rails go badly together, so watch where you put your feet.

Beacon Street through Brookline, falling steadily the whole way. If you have anything left, this is the mile to spend it.

Beacon Street, level now, and it will feel longer than it is. Pick a runner ahead of you, reel them in, then pick another one.

Kenmore, a swing onto Commonwealth, then the last right and left onto Boylston Street. Flat, loud, and straight to the line.