How to Train for a Half Marathon This Fall

Training for a fall half marathon requires 10–16 weeks of structured running — built around progressive mileage increases, two to three quality workouts per week, and deliberate recovery — to carry you 13.1 miles at a sustainable pace. You don’t need to run every day, and piling on miles without structure is the single fastest route to an overuse injury that ends your race season before it starts.

Step 1: Establish Your Base Before the Plan Begins

Your training plan is only as reliable as the fitness foundation beneath it. Runners who begin a half marathon program with fewer than 15 miles per week in their recent history absorb workload faster than their tendons and connective tissue can adapt, which is a separate — and slower — timeline than cardiovascular adaptation. Research published in the Journal of Strength and Conditioning Research confirms that musculoskeletal injury risk rises sharply when weekly mileage increases faster than 10% per week, regardless of aerobic fitness level. Spend 2–4 weeks before your formal program getting your weekly volume to 15–20 miles at an easy conversational effort. That base gives the program something real to build on.

Step 2: Structure Your Weekly Training Around Three Run Types

Every productive half marathon training week contains three distinct run categories, and each one has a specific physiological purpose. Running the same moderate pace every day is a common mistake that produces mediocre adaptation while accumulating fatigue. The NSCA’s position on endurance development emphasizes periodization — the systematic variation of intensity and volume — as the mechanism by which trained athletes continue improving. Build your week around these three categories and assign them to specific days with at least 48 hours separating hard efforts.

Easy Runs (60–70% of Max Heart Rate)

Easy runs make up 70–80% of your total weekly mileage. They build aerobic base, improve fat oxidation efficiency, and promote active recovery without generating meaningful fatigue debt. Run at a pace where you can hold a full conversation in complete sentences — if you can’t, you’re running too hard. Most runners underestimate how slow “easy” actually feels, particularly in the first four weeks of a build.

The Long Run (Easy Pace, Extended Duration)

The long run is the single most important session of your training week. It builds the muscular endurance, glycogen storage capacity, and mental habituation to sustained effort that a half marathon demands. Begin your long run at 8–10 miles if your base allows, and extend it by 1 mile every 7–10 days until you reach 12–13 miles, 2 weeks before race day. Run your long runs 45–90 seconds per mile slower than your goal race pace to preserve recovery capacity for the week’s other sessions.

One Quality Workout Per Week (Tempo or Intervals)

One workout per week should target your lactate threshold — the intensity at which lactate accumulates faster than your body can clear it. Tempo runs at 80–85% of max heart rate, held for 20–40 minutes, are the primary tool. Research published in the Journal of Applied Physiology demonstrates that threshold training increases the running velocity at which lactate inflection occurs, which directly translates to a faster sustainable race pace. A straightforward prescription: 3 miles at a comfortably hard effort — hard enough that speaking requires conscious effort — followed by 10 minutes easy. Increase tempo duration by 5 minutes every 2 weeks.

Step 3: Build Mileage Progressively and Protect the 10% Rule

Weekly mileage increases must follow a ceiling of 10% above the previous week’s total. This isn’t a conservative suggestion — it’s a structural constraint grounded in connective tissue biology. Bone, tendon, and ligament remodeling operates on a timeline of 6–8 weeks, substantially slower than cardiovascular adaptation, which means your lungs and heart will always feel ready before your tissues are. A runner logging 30 miles per week should not exceed 33 miles the following week. Every 3rd or 4th week, reduce your mileage by 20–30% to allow full tissue recovery before the next loading block. This scheduled reduction — called a cutback week — is where adaptation is consolidated, not lost.

Step 4: Add Strength Training to Reduce Injury Risk

Strength training 2 times per week — focused on the posterior chain, single-leg stability, and hip abductors — meaningfully reduces running injury incidence. The British Journal of Sports Medicine published a meta-analysis showing that lower-body strength training reduced overuse injury rates in runners by up to 50% compared to running-only programs. The mechanism is simple: stronger glutes, hamstrings, and calves absorb and transfer force more efficiently, reducing the compensatory loading that produces stress fractures and IT band issues. Prioritize dumbbell exercises for leg strength like Romanian deadlifts, single-leg squats, hip thrusts, and calf raises — 3 sets of 8–12 reps per movement — on days that follow easy runs, never on the day before a long run or tempo session.

Key Strength Movements for Half Marathon Runners

• Romanian deadlift: 3 sets of 8–10 reps — targets the hamstrings and glutes that power each push-off
• Single-leg squat (Bulgarian split squat): 3 sets of 10 reps per leg — trains the hip stability that prevents valgus collapse at mile 10
• Hip thrust: 3 sets of 12 reps — develops glute strength that protects the lower back and knee on long efforts
• Single-leg calf raise: 3 sets of 15 reps — builds the Achilles tendon resilience that runners consistently underestimate until it fails

Step 5: Manage Nutrition to Support Your Training Volume

As your weekly mileage crosses 25–30 miles, your carbohydrate requirements increase substantially and your recovery depends on protein intake that most recreational runners don’t prioritize. Research published in the American Journal of Clinical Nutrition establishes 1.4–1.7 grams of protein per kilogram of bodyweight per day as the target range for endurance athletes in active training blocks. Carbohydrate intake should scale with training volume — on long run days, target 5–7 grams per kilogram of bodyweight to ensure muscle glycogen is fully replenished within the 24-hour recovery window. On easy days, 3–5 grams per kilogram is sufficient. Treat race-week nutrition as practice: begin using the gels or chews you plan to use on race day during your long runs at week 6 or earlier, not two days before the event.

Step 6: Execute a Proper Taper in the Final 2 Weeks

The taper is a non-negotiable component of half marathon preparation, not a reward for completing hard training. During the final 2 weeks, reduce total mileage by 30–40% while preserving workout intensity — cut volume, not pace. The physiological rationale is well-established: glycogen stores super-compensate, soft tissue micro-damage repairs fully, and neuromuscular efficiency peaks when training stress is reduced after a sustained loading period. Many runners sabotage their taper by running more than prescribed because they fear losing fitness. Fitness is not lost in 14 days. What you built over 12–14 weeks of structured training will be present on race day — the taper ensures you arrive there fully recovered rather than carrying accumulated fatigue into the start corral.

Training for a half marathon this fall comes down to one organizing principle: structured progressive overload applied consistently over 10–16 weeks, with deliberate recovery built into every phase. Run most of your miles easy, complete one quality session per week, build mileage by no more than 10% each week, strengthen the muscles that protect your joints, fuel the training volume you’re generating, and taper fully before race day. Runners who execute these steps methodically — without shortcuts and without panic-stacking miles late in the cycle — arrive at the start line ready to run 13.1 miles at the pace they trained for.

Frequently Asked Questions