Your leg workouts should support marathon training, not leave your quads too sore to hit your intervals or long run. The challenge is especially sharp for lifters preparing for a time goal: you want to retain strength and muscle, but hard leg days can steal quality from the running sessions that matter most. Knowing how to adjust leg day during marathon training means managing exercise choice, training failure, total volume, and timing.
Quick Answer
Keep lower-body strength work during marathon training, but reduce its cost. Prioritize two short weekly sessions, use moderate loads, stop most sets with 2-3 reps in reserve, and place the harder session after a key run rather than before one.
As running mileage and workout intensity rise, lower lifting volume before reducing all strength work. A practical starting point is 4-8 challenging weekly sets each for quads, hamstrings, and glutes, rather than a bodybuilding-style 15-25 sets per muscle group.
Do not take compound leg lifts to failure during a marathon block. Save any near-failure effort for low-risk isolation work, used sparingly and far from important runs.
Why This Happens
A hard leg day creates more than ordinary muscle soreness. Heavy eccentric loading from squats, lunges, Romanian deadlifts, leg presses, and step-ups can cause muscle damage, stiffness, and temporary changes in coordination. Those effects can make your stride feel flat, limit knee drive, and make marathon pace feel harder than it should.
The bigger issue is fatigue overlap. Running workouts need fresh legs and a responsive nervous system. A squat session taken to failure can compromise the next day’s track workout even if the soreness feels manageable. Conversely, a demanding interval session can turn a normally sensible lifting workout into excessive stress when it is stacked too closely.
Hybrid athletes also often carry over bodybuilding rules that do not fit a marathon build. More volume, more exercise variety, and more failure training can be effective for hypertrophy when recovery resources are available. During a marathon plan, running already supplies a large lower-body workload. The strength program must now maintain durability and force production with the smallest effective dose.
Step-by-Step Method
1. Identify the runs that cannot be compromised
Put your long run and your highest-quality workout first. For most marathon plans, those are a tempo, threshold, interval, or marathon-pace session plus the weekly long run. Everything else, including lifting, should fit around them.
If your goal is a sub-4 marathon, marathon-pace work and long-run quality are usually more race-specific than adding another hard set of leg extensions or lunges.
2. Use a two-session lower-body template
Most runners do well with one moderately hard lower-body session and one lighter maintenance session each week. Beginners to strength training may need only one session. Experienced lifters can sometimes handle two, but only if their run quality remains stable.
A useful weekly pattern is:
- Hard run day: Complete the key run first, then lift later that day if practical.
- Easy or recovery day: Use a brief lighter strength session, or rest completely.
- Day before long run: Avoid demanding lower-body lifting.
Stacking stress on the same day creates a clearer recovery window. Splitting a hard run and hard leg day across consecutive days often creates two mediocre sessions instead.
3. Cut volume before cutting load
Keep some moderately heavy work because it helps maintain strength efficiently. Instead of turning every lift into high-rep conditioning, reduce the number of work sets.
For example, replace five exercises for four sets each with two or three exercises for two to three sets each. A lower-body session could include:
- Squat, trap-bar deadlift, or leg press: 2-3 sets of 4-8 reps
- Romanian deadlift or hamstring curl: 2-3 sets of 6-10 reps
- Split squat, step-up, or calf raise: 1-2 sets of 8-12 reps
Choose movements you already perform well. Marathon training is rarely the right time to introduce deep high-rep Bulgarian split squats, a new deadlift variation, or a high-volume plyometric program.
4. Train with reps in reserve
For compound lifts, finish most working sets with 2-3 reps in reserve (RIR). That means you could have completed two or three clean repetitions with good form if necessary. This provides a meaningful strength stimulus without the disproportionate soreness and recovery cost of failure.
You can occasionally use 1-2 RIR on a final set when mileage is moderate and no key run is near. Avoid true failure on squats, deadlifts, lunges, and heavy leg presses during the main marathon build.
5. Match exercise selection to your recovery capacity
Select exercises that give you a strong stimulus without making you limp down stairs for three days. Machines can be useful because they require less balance and technical focus when run fatigue is high. Bilateral movements may also be easier to recover from than large volumes of unilateral work.
Keep some calf work if your calves tolerate it. Strong calves and soleus muscles help with repeated push-off, but aggressive new calf volume can aggravate Achilles or lower-leg symptoms. Add it gradually.
6. Adjust by training phase
Early in a marathon block, you can maintain a little more lifting volume. During peak mileage, reduce sets and remove optional isolation work. In the final 10-14 days, retain only brief, familiar maintenance lifting if it does not produce soreness.
Do not attempt strength PRs close to race day. The goal is to arrive with fresh legs, not prove that your squat has held steady.
Common Mistakes
Taking every leg exercise to failure
Failure training creates fatigue that is often out of proportion to its benefit during marathon preparation. Instead, stop compound lifts at 2-3 RIR and keep isolation exercises controlled, with only occasional near-failure sets when they do not affect running.
Lifting hard the day before intervals or a long run
A heavy lower session before a key run can reduce pace, alter mechanics, and turn a targeted workout into survival mode. Instead, lift after your key run, or schedule lower-body work at least 48 hours before the next major run when possible.
Keeping bodybuilding volume while adding marathon mileage
Ten sets of squats, lunges, leg press, leg extensions, curls, and calves may have worked in an off-season. It is usually too much alongside long runs and speed work. Instead, reduce total sets, keep a few effective movements, and monitor run performance.
Replacing strength work with random high-rep circuits
High-rep jump squats, walking lunges, and metabolic finishers can leave the legs more fatigued than focused strength work. Instead, use controlled sets with clear load, reps, and rest periods.
Ignoring delayed soreness patterns
Some athletes feel fine immediately after lifting but struggle 24-48 hours later. Instead, track your soreness, easy-run pace, and key-workout quality for two weeks. Your schedule should respond to actual recovery, not only how you feel leaving the gym.
Checklist or Decision Table
| Situation | Best leg-day adjustment | Why |
|---|---|---|
| Key interval workout tomorrow | Skip hard lower lifting; use mobility or upper body instead | Protects running mechanics and workout quality |
| Long run is within 24 hours | Avoid squats, lunges, and heavy calf work | Reduces soreness and glycogen drain |
| Mileage is rising but runs still feel good | Keep load similar; remove 1-2 sets per exercise | Maintains strength with less fatigue |
| Legs are sore for more than 48 hours | Reduce eccentric-heavy lifts and stop farther from failure | Lowers muscle damage and recovery time |
| Peak marathon weeks | Use one hard-maintenance session plus one optional light session | Running has priority during high fatigue |
| Race is 10-14 days away | Cut volume sharply; use only familiar, easy maintenance work | Avoids carrying soreness into the taper |
| Key runs are slowing despite normal effort | Reduce lower-body volume first, then frequency if needed | Identifies lifting as a controllable fatigue source |
When This Advice Does Not Apply
This approach is for a runner whose primary near-term goal is the marathon. If your main goal is maximal muscle gain, powerlifting performance, or a strength competition, you may accept slower run progression and use a different priority order.
Athletes new to lifting should start more conservatively than the example volumes above. Even a small amount of resistance training can cause substantial soreness at first. Likewise, runners returning from injury may need individualized exercise selection from a qualified physical therapist, coach, or clinician.
Persistent focal pain, swelling, altered gait, numbness, or pain that worsens as you run is not ordinary training soreness. Stop trying to solve it by rearranging leg day and seek appropriate professional assessment.
Realistic Example
Consider a longtime bodybuilder training for a sub-4 marathon. His old lower session included heavy back squats, Romanian deadlifts, walking lunges, leg press, leg extensions, hamstring curls, and calf raises, with several final sets pushed to failure. He scheduled it on Tuesday, then wondered why Wednesday intervals felt stiff and why Saturday long runs began with dead quads.
A better setup keeps Tuesday’s interval session first and moves a shortened strength workout to later that day: three sets of squats at 2 RIR, two sets of hamstring curls, and two sets of calf raises. On Friday, he performs two easy sets of Romanian deadlifts and light single-leg work only if Saturday’s long run is not demanding. During peak mileage, he drops Friday lifting altogether. His gym numbers may not rise during the block, but his key runs become more reliable, which is the useful trade-off.
Final Takeaway
During marathon training, leg day should maintain strength and resilience rather than create a second lower-body sport. Put key runs first, keep compound lifts away from failure, reduce volume as mileage rises, and schedule the hardest lifting after—not before—important runs.
If lifting makes your quality sessions consistently worse, the answer is usually fewer hard sets and better timing, not abandoning strength work entirely.
FAQs
Should I stop doing leg day while training for a marathon?
No, most marathon runners should keep some lower-body strength training. A small, consistent dose can help maintain strength, tissue capacity, and confidence under fatigue. The important change is reducing volume and avoiding failure-based sessions that interfere with running. One or two short sessions per week is enough for many runners. If your long runs, intervals, or marathon-pace workouts repeatedly deteriorate after lifting, first cut lower-body sets and improve scheduling before removing strength training completely.
How many days before a long run should I do leg day?
Ideally, do your hardest leg day at least 48 hours before a demanding long run, although individual recovery varies. An even better option is to lift after a midweek key run, giving you a consolidated hard day and more recovery before the weekend. Avoid high-volume squats, lunges, and calf work within 24 hours of a long run. If your long run is easy and short, a light maintenance session may be fine, but do not use it as a test of your recovery limits.
Can I squat heavy during marathon training?
Yes, you can squat moderately heavy during marathon training if you keep the volume low and avoid grinding reps. Sets of roughly 4-8 repetitions with 2-3 reps in reserve often preserve strength without the recovery burden of high-volume bodybuilding work. Place squats after a quality run or far from your next important running session. As marathon mileage peaks, reduce the number of squat sets rather than chasing heavier loads. Stop attempting personal records during the final weeks before the race.
Is it better to lift legs before or after a hard run?
For a marathon-focused athlete, lift legs after a hard run in most cases. Running first protects the quality of the workout that directly develops race-specific fitness, such as threshold pace, intervals, or marathon pace. Lifting afterward also places stress on one day, allowing more complete recovery afterward. If the sessions must be separated, leave several hours between them, eat and hydrate well, and keep the lifting session short. Reverse the order only if strength performance is your primary goal.
Should marathon runners train leg exercises to failure?
No, marathon runners generally should not train compound leg exercises to failure during the main training block. Failure on squats, deadlifts, leg press, and lunges raises soreness, technique breakdown, and recovery demands without being necessary for maintaining strength. Stop most sets with 2-3 reps in reserve. A controlled isolation set, such as hamstring curls or leg extensions, can occasionally be taken closer to failure if it does not affect running, but it should not be a weekly requirement.
How should I taper strength training before a marathon?
Reduce lower-body lifting volume substantially during the final 10-14 days before a marathon. Keep only familiar movements, use lighter or moderate loads, stop well short of failure, and avoid any exercise that reliably causes soreness. Some runners perform one brief maintenance session around 10 days out, while others feel best skipping lower-body lifting altogether in race week. Do not introduce new exercises, deep eccentric work, or heavy calf training. Fresh, coordinated legs matter more than preserving every gym number.