12 Weeks to Fitness: Intermediate Half Marathon Training Plan

This plan is ideal for runners who:

• Can already run continuously for at least 45 minutes
• Have completed a 10K or half marathon before
• Want to challenge themselves and improve their finish time
• Are comfortable with regular running and cross-training

If you’re new to running or haven’t yet run a 10K, consider starting with a beginner plan before moving to this intermediate schedule.

A 12-week training plan is widely recommended for intermediate runners. This timeframe allows for a gradual increase in mileage and intensity, reducing the risk of injury while maximising fitness gains. Over 12 weeks, you’ll build a strong running base, introduce speedwork, and peak just in time for race day.

• Gradual progression: Reduces injury risk and helps your body adapt
• Balanced intensity: Mixes easy runs, long runs, and speedwork
• Time to recover: Includes rest and recovery days for optimal performance
• Mental preparation: Builds confidence and race-day readiness

Easy runs are performed at a comfortable, conversational pace. These runs help build aerobic endurance, improve running economy, and promote recovery between harder sessions. Aim for 30–60 minutes at a pace where you can comfortably chat with a running partner.

Long runs are the cornerstone of any half marathon plan. These runs increase your endurance and teach your body to burn fat efficiently. Start with a long run of about 60 minutes and gradually increase the duration each week, peaking at around 90–120 minutes before tapering for race day.

Speedwork includes interval and tempo runs. Interval runs consist of short bursts of fast running followed by recovery periods, while tempo runs are sustained efforts at a challenging but manageable pace. These sessions improve your lactate threshold and running speed.

Hill training builds strength and power in your legs, improves running form, and increases cardiovascular fitness. Incorporate hill repeats or hilly routes into your training at least once every two weeks.

Cross-training (such as cycling, swimming, or yoga) and strength training help prevent injury, improve overall fitness, and balance muscle development. Aim for one or two cross-training sessions per week, focusing on low-impact activities that complement your running.

Rest and recovery are just as important as training. Schedule at least one full rest day per week to allow your body to repair and adapt. Listen to your body and adjust your training if you feel fatigued or notice any signs of overtraining.

Proper nutrition and hydration are the foundation of any successful half marathon training plan. They ensure your body has the energy and resources it needs to perform, recover, and adapt to the increasing demands of your training schedule.

Carbohydrates are the primary fuel source for endurance running. They break down into glucose, which your muscles use for energy. For runners, around 45–55% of daily calories should come from carbs, with sources including whole grains, fruits, vegetables, and starchy foods like sweet potatoes and oats.

Protein is essential for muscle repair and recovery. Aim for 15–20% of your calories from protein, found in lean meats, fish, eggs, dairy, beans, nuts, and seeds. Protein helps rebuild muscle fibres damaged during training and supports your immune system.

Healthy fats are Important for long-lasting energy and overall health. About 25–35% of your calories should come from healthy fats found in avocados, nuts, seeds, and oily fish.

Hydration is crucial. Drink water throughout the day and increase intake before, during, and after runs. For runs longer than 60–90 minutes, consider electrolyte drinks to replace salts lost through sweat.

Engaging in activities other than running that support your overall fitness. Examples include cycling, swimming, yoga, and elliptical training. Cross-training reduces the risk of overuse injuries by giving your running muscles a break while still building cardiovascular fitness.

Examples of Cross-Training Activities

• Cycling → Builds leg strength and cardiovascular fitness with minimal impact.
• Swimming → Works your entire body, improves lung capacity, and is gentle on joints.
• Yoga → Increases flexibility, balance, and mental focus while aiding recovery.
• Elliptical Training → Mimics running motion without the impact, ideal for recovery day.
• Hiking → Builds strength and endurance while enjoying the outdoors.

Strength training is an essential component of any intermediate half marathon training plan, as it helps runners develop greater muscle strength and endurance—particularly in the legs and core—through bodyweight and resistance exercises such as squats, lunges, planks, and calf raises. These targeted workouts not only improve running economy and form by promoting muscle balance and efficient movement, but also play a crucial role in reducing the risk of common running injuries. By regularly incorporating strength sessions into their training schedule, runners can build a more resilient body, enhance their overall stability and power, and better prepare themselves for the physical demands of a half marathon, ultimately supporting improved performance and confidence on race day.

Choosing the perfect half marathon kit is all about comfort, functionality, and preparation for the conditions you’ll face. Start with well-fitted, supportive running shoes that have been tested in training, and pair them with moisture-wicking socks and lightweight, breathable clothing to keep you cool and dry. Don’t forget to include a water-resistant jacket for unpredictable weather, along with a water bottle or hydration pack for on-the-go drinks. Pack energy gels or snacks for fuel during the race, and bring a change of clothes and shoes for after you cross the finish line. Finally, add any personal essentials like a sports watch, headphones, and safety pins for your race number—making sure every item is tried, tested, and ready for race day. For a full checklist and expert tips, read our comprehensive guide below.