Should I lift during a race block?

Yes. Two full-body sessions a week at moderate load maintain muscle very well and preserve the running economy benefit, and stopping entirely removes a stimulus your body is adapted to at exactly the moment you want nothing to change.

How much lifting maintains muscle?

Considerably less than building it requires — roughly eight to twelve fractional sets per muscle per week at moderate load, across two sessions. That gap between the maintenance dose and the growth dose is the fact that makes lifting through a race block possible at all.

Should I stop lifting during a taper?

No. Reduce the volume and keep the load, with the last heavy lower-body session about ten days out. Stopping removes an adapted stimulus during the two weeks when you specifically want nothing about your body to change.

Will I lose strength during a race block?

Some, and less than you expect if you keep two sessions a week. What is usually lost is not strength but the energy to express it — a block run in an accidental deficit costs far more than the reduced lifting volume does.

When can I build muscle again?

Three to sixteen weeks after the race, with endurance volume held at easy only. That window is the highest-return period of your year for lean mass and it is the one most athletes waste, either resting for a month or starting base training immediately.

Lifting Through a Race Block Without Losing It

The block plan

Phase	Weeks out	Lifting	Fractional sets/muscle	Goal
Base	18–12	3 sessions	12–14	The only window where building is realistic
Build	12–4	2 full-body	10–12	Hold
Taper	4–0	2 sessions, volume down, load held	8–10	Keep the stimulus, drop the fatigue
Race week	—	One light session early	—	Movement

The single most useful decision is made at week eighteen: name which goal is primary. It is the race. Everything else follows, and a lot of frustration disappears once it is said out loud.

What to cut, in order

Accessory volume. Lateral raises are not why you are tired.
Lifting frequency, consolidating to full-body sessions rather than cutting total volume proportionally.
Intensity on lower-body work in the peak weeks — moderate loads, not maximal.
Never the endurance work. It is the goal.

What does not get cut: protein, sleep, or the lifting entirely.

The two sessions

Full body, compounds, two to three sets each at 2 to 3 RIR. Not to failure — failure on a compound costs disproportionate systemic fatigue and you have none spare.

One knee-dominant — squat or leg press
One hip-dominant — Romanian deadlift or hip thrust
One horizontal push, one horizontal pull
One vertical push, one vertical pull
Trunk, anti-rotation and anti-extension

Keep upper body in. It costs almost nothing in endurance terms — different tissue, minimal local competition — and it is where an endurance athlete's muscle is most easily lost.

Where the sessions go

Two rules, and they are not flexible.

Never the day before a key session. Lower-body fatigue costs the most on quality endurance work.

Never the day after a long session. You are already drawing down.

That usually leaves the two lightest endurance days. Separate the lift from that day's session by six or more hours — the measured concurrent-training interference falls from about −0.66 to about −0.10 at that separation. The detail.

A shape for a Saturday long session:

Day	Session
Mon	Easy endurance + full-body lift, 6 h apart
Tue	Key session
Wed	Easy endurance
Thu	Easy endurance + full-body lift, 6 h apart
Fri	Rest or very easy
Sat	Long session
Sun	Rest or recovery

Both lifts are two days clear of Saturday, and Tuesday's key session follows Monday's lift by a full day rather than sharing legs with it.

What actually costs you muscle, and it is not the reduced lifting

Energy.

Running costs roughly 1 kcal per kilogram of bodyweight per kilometre. For a 165 lb (75 kg) athlete:

Weekly mileage	Extra daily cost
20 mi	~345 kcal/day
35 mi	~600 kcal/day
50 mi	~860 kcal/day
65 mi	~1,120 kcal/day

If intake does not move with it, you are in a large sustained deficit — and a large sustained deficit while training hard is exactly how muscle is lost, how bone density falls, and how the endocrine consequences of low energy availability begin.

This is not solved by eating more on faith. Measure maintenance from what your weight actually did against what you actually ate, so the volume is counted whether or not you tracked the sessions. Re-measure at week eight when volume has risen; the number will have moved by several hundred calories. The method.

Protein at 1.0 g per pound, held constant. If protein is being squeezed to make the calories work on a peak week, the calorie target is wrong, not the protein.

The taper, and why not to stop

Keep lifting through the taper at reduced volume with load maintained.

Stopping entirely removes a stimulus your body is adapted to at exactly the moment you want nothing to change. The two-week taper is not the time to introduce a novel condition, and a complete stop is a novel condition.

Last heavy lower-body session about ten days out. After that: movement. Two light full-body sessions in the final fortnight, nothing that produces soreness, nothing new.

After the race

Three weeks of genuine rest — not "active recovery" that becomes easy running that becomes tempo running.

Then twelve to sixteen weeks of strength-primary work with endurance held at easy volume only. That window is the highest-return period of your year for lean mass, because your aerobic base decays slowly and your capacity to build muscle is at its highest precisely when endurance volume is lowest.

It is also the window most athletes waste, either resting for a month or starting base training in November. Planning it.

Common mistakes

Stopping lifting entirely at week twelve because the running got hard.
Not raising intake as volume ramps, which is what actually costs the muscle.
Lifting the day before a key session.
Trying to build during the build phase. Name the goal.
Stopping during the taper.
Cutting protein to make the calories fit.

What to do next

Put the two lifting sessions in your calendar for the whole block now, on the two lightest endurance days, before the block starts. The sessions that get scheduled in week fourteen do not happen; the ones written down in week eighteen do.