The TSK 25K Kolkata runs 25 kilometres through the Maidan and past Victoria Memorial in December. A 25K plan is neither a half-marathon plan nor a full-marathon plan. It is its own honest middle ground. This guide is a twelve-step training protocol, built for clarity, correct sequencing, and durable fitness across a twelve-week block.
Step 1: Establish your baseline
Before week one, run an easy 10K. Record the finish time, the perceived effort, and the heart rate. That is your starting point. Feed the time into the STRIDD pace calculator to estimate your current 25K pace.
The number on the screen is not the goal. Honesty about where you are today is the goal. If you cannot yet run a continuous 10K at conversational pace, hold off on the 25K plan and build base mileage for four to six weeks first.
Step 2: Set a weekly structure
The standard week has five running days, one cross-training day, one full rest day. Tuesday and Thursday are quality sessions. Saturday is the long run. Wednesday and Sunday are easy. Monday is rest. Friday is cross-training or rest.
Step 2a: Why the structure matters
A 25K demands aerobic endurance and tempo strength in roughly equal measure. Five running days build the aerobic base. Two quality sessions sharpen the tempo. The shape of the week is the architecture of the result, so do not improvise it week to week and hope it holds together.
Step 3: Weeks 1 to 4, base building
Easy running.
The long run starts at 12 km in week 1 and grows to 18 km by week 4. Tuesday runs are aerobic with a few short pickups at the end. Thursday runs are aerobic too, slightly longer than Tuesday. None of it is fast, and none of it should feel hard yet.
The goal across this block is simple. Make the body comfortable with five running days a week before any tempo work begins. Read the India climate guide for advice on training through October and November conditions in Kolkata.
Step 4: Weeks 5 to 8, tempo block
Now the quality work arrives. Tuesday becomes a tempo session, 20 to 30 minutes at comfortably hard effort. Thursday becomes intervals: 4 to 6 repetitions of 4 minutes at 5K race effort, with 2-minute easy jogs between them.
Step 4a: Saturday long runs
Long runs grow to 22 km by week 8. Include one or two long runs where the final 4 km is held at goal 25K pace. This teaches the legs what holding a pace when tired actually feels like, which is the one thing a race will demand of you that easy running never does. For a 25K, that skill is not optional.
Step 5: Weeks 9 to 11, race-specific block
Tuesday tempos extend to 35 to 40 minutes. Thursday intervals get longer: 5 repetitions of 6 minutes at 10K race effort, with 2-minute easy jogs between. Saturday long runs touch 25 km in week 10, the longest of the build.
The race-specific block is where the build either matures or breaks. If something hurts beyond normal muscle soreness, take an extra easy day. Push through accumulated fatigue. Never push through pain.
Step 6: Week 12, taper
Volume drops by 40 to 50 percent. Intensity stays sharp but compressed. Two short tune-up sessions, one tempo of 15 minutes and one set of strides, both well within yourself. Race fitness is built in weeks 1 through 11. The taper exists only to protect it.
Step 7: Strength and mobility
Two short strength sessions a week, 20 to 30 minutes each. Single-leg squats, calf raises, glute bridges, plank variations. Skip heavy barbell work in the final four weeks. A short mobility routine after every run keeps the hips and ankles loose.
Step 8: Cross-training
Friday cross-training builds fitness without running impact. Cycling, swimming, elliptical, or yoga all work. 45 to 60 minutes at easy effort. Skip it if you are tired. The goal is supplementary fitness, not extra fatigue.
Step 9: Nutrition through the build
Eat normally. Carbohydrate at every meal. Protein at every meal. Hydrate continuously. A training block is not the time to attempt a body composition change. That comes later. Underfuelling sabotages adaptation more reliably than overtraining does.
Step 9a: Fuelling long runs
Practise race-day fuelling from week 5. Take a gel or a proven carb source every 30 to 35 minutes on long runs of 18 km or more. Test your water and electrolyte intake. Race day is not the day for a new product.
Step 10: Race week
Sleep more than usual. Eat normally. Lay your kit out two nights before. Hydrate steadily. Check the bib pickup details and the travel logistics for the Kolkata venue at least 48 hours in advance. Avoid new restaurants in the final 48 hours. Race week is the most boring week of your training cycle, and that is exactly the point.
Step 11: Race-day pacing
The route through the Maidan and past Victoria Memorial is largely flat. Start at conversational effort for the first 5 km. Settle into goal pace from km 6 to 18. Decide the final 7 km on feel.
The 25K distance is uniquely placed. Long enough to demand discipline, short enough to allow a strong closing kick if the legs hold. Use the STRIDD plan generator to map a customised plan, or follow the broader half-marathon framework for cross-reference on similar-distance plans.
Step 12: Recovery and the next block
Plan for a full week of light movement after race day. Walk daily. Two short jogs in week two. Most healthy runners are back to structured training by week three. Skip speed work for ten days. The recovery is the first chapter of the next block, not the postscript to this one.
Accessibility note
This plan assumes a healthy adult runner with a base of at least 25 km a week. Anyone returning from injury, managing a chronic condition, or new to structured training should consult a coach or physiotherapist before starting. Adapt the plan to your situation. Do not force your situation to fit the plan.
For registration, categories, and start times, see the TSK 25K Kolkata event page. Browse the Running Lab for more pieces on race-week strategy, pacing, and recovery.