CIM Marathon Training Plan: How to Use the Downhill Without Wrecking Your Quads

CIM (California International Marathon) runs the first Sunday in December, point-to-point from Folsom Dam to the steps of the Sacramento State Capitol. It is the closest thing the US has to a perfect BQ-chase course: net downhill, cool weather, honest pacing, and a field full of runners who came to run a specific time. If you want to qualify for Boston, CIM is the course most people pick.

This article covers what a CIM-specific training plan looks like — the modifications that make sense for a net-downhill December marathon. For the broader marathon picture, see the marathon training plan guide. For BQ-tier training, see the sub-3 marathon plan. To check the BQ cushion you actually need, run the Boston qualifying time calculator.

What's Different About CIM

• Net downhill (340 ft). Not Boston-level downhill, but enough to load quads over 16 sustained miles.
• Rolling first 6 miles. Small climbs and descents. Honest pacing here protects the rest of the race.
• December weather. Cool start (40s), low humidity, often calm wind. The opposite problem from a heat marathon.
• Time-goal field. Pace groups for every common BQ time. Runners around you are mostly chasing the same line.
• Point-to-point logistics. Buses from the finish to the start. Race-morning is longer than at a loop course.

Training Modifications for CIM

1. Add Some Downhill Long Runs

Not as many as Boston demands — CIM's downhill is gentler — but at least twice in the build, run a 16-20 mile long run that includes 8-12 miles of sustained gentle downhill (1-3% grade). If you live somewhere flat, treadmill at -2% works. So does running a route that ends at a lower elevation than it starts.

The point is to teach the quads to handle eccentric loading over distance. Without it, the back half of CIM hurts more than it should.

2. Marathon-Pace Sessions Run Slightly Downhill

If you can, do at least one of your marathon-pace workouts on a gently downhill route. The leg-turnover at goal pace on a slight descent feels different from flat marathon pace — you want race-day pace to feel familiar.

3. Don't Over-Train the Hills

CIM's "rolling" first 6 miles are small bumps, not real hills. You don't need hill repeats in a CIM build. Time that would go into hill work in a Boston build can go into more threshold and marathon-pace work instead.

4. Practice Cold-Weather Race Pacing

December cold start lowers perceived effort for the first few miles — you feel like you can run faster than you should. Long runs in similar weather (early morning, December training runs) build the calibration. The biggest CIM mistake is going out at 5K pace because the legs feel fresh.

Pacing CIM on Race Day

• Miles 1-6 (rolling): Goal pace average, but let the downhills give you splits 5-10 seconds faster than goal pace and the small uphills cost you 5-10 seconds. Don't fight the splits. Run by effort.
• Miles 6-22 (gentle downhill): Lock into goal pace. The course will help.
• Miles 22-26.2 (flat): Hold goal pace. If you've paced honestly, you can push the final 2-3 miles.

Print a pace band before race day. CIM is a course where a per-mile band keeps you honest in those rolling early miles — it's easy to glance at the watch, see a 6:35 split when you wanted 6:51, and think "great, banking time" until mile 20 explains otherwise. Use the marathon pace band generator to print one.

Handling the Cold Start

• Wear throwaway layers at the start corral — long sleeve over your race shirt, gloves, sometimes a beanie. CIM is famous for the pile of donated clothing at the start.
• Warm up less than you would at a warmer race. Five minutes of light jogging and dynamic mobility is enough.
• Eat breakfast earlier than usual. With a 7:00 AM start and a 5:00 AM bus, race-day fueling has to be sorted out the night before.
• Hydration is easier to under-do in cold weather because you don't feel thirsty. Drink at every aid station, not just when you feel like it.

Common CIM Mistakes

Going out too fast on the rolling section. The downhills feel free. The uphills feel cheap. Splits look great. Then mile 20 happens.

Skipping downhill long runs in training. Quads that haven't trained eccentric loading will give out somewhere in miles 18-22. The damage is mechanical, not metabolic — fueling can't save you.

Underestimating point-to-point logistics. The bus to the start is 60-90 minutes. Pre-race nerves plus that long sitting can compound. Practice on at least one long run.

Treating the field like Boston. CIM is a fast field but it's not Boston. There's a wider mix of qualifiers, BQ-chasers, and recreational runners. Don't let the early kilometers' crowd surge dictate your pace.