The Marathon Runner’s Guide to Strength Training
What’s the secret to running faster and staying injury-free during marathon training? Strength training is the often-overlooked aspect of your preparation that can enhance your performance and keep your body injury-free through the challenges of 26.2 miles.
Strength training will reduce the risk of injury
When training for a marathon, the cumulative mileage puts significant stress on your joints, cartilage, and bones, increasing your risk of injury. Resistance-based weight training prepares your body to handle this stress by strengthening and reinforcing muscles and connective tissue. Without proper muscular preparation, overuse injuries such as shin splints, runner’s knee, or stress fractures become more likely. By incorporating strength training into your routine, you can better equip your body to handle the repetitive impact and musculoskeletal demands of running the 26.2 miles. In particular, unilateral resistance exercises — those that focus on one limb or side of the body at a time— are especially effective. These movements help correct muscular imbalances, which are a common cause of running-related injuries.
Strength training will make you a more efficient runner
Strength training enhances muscle power and efficiency, allowing you to use less energy with each stride. It also strengthens neuromuscular connections, improving how efficiently your brain signals your muscles to contract, resulting in more powerful, effective movements.
Weight training also strengthens your core and improves posture, preventing the rounded shoulders often seen as fatigue sets in during long runs. A strong core helps you maintain an upright posture, breathe more efficiently, and avoid side stitches. Additionally, building muscular endurance delays fatigue, keeping you running strong for longer.
When and how to incorporate strength training into your marathon prep
Scheduling your strength training sessions mindfully is key to maximising their benefits without compromising your running performance.
Aim for at least one dedicated strength training session each week, lasting between 30 minutes and an hour. A second shorter session, focusing slightly more on mobility and stability, is also beneficial.
Ideally, perform your strength sessions on separate days from your runs to allow your body more time to recover. If that’s not possible, aim for at least a six-hour gap between your run and strength workout. If you choose to do both on the same day, always prioritise your run first, so your legs are fresh for your mileage.
Consider scheduling your easier runs for the day(s) following your strength session(s). This allows your body to recover while still maintaining your running volume. If you’re feeling particularly fatigued from a hard run, you can adjust the intensity of your strength session by incorporating more mobility exercises or reducing the load of some of your strength exercises.
To avoid interference with your running, it’s best to start strength training at the same time as you begin your marathon training. This will give your body a chance to adjust gradually, minimising any potential soreness that could hinder your runs, especially as your mileage increases. Starting strength training later in your programme, when your mileage is higher, could lead to excessive fatigue or impact your running form.
How to structure your strength training programme
When it comes to structuring a strength programme alongside marathon training, I like to guide my clients through 4 phases:
Phase One
In Phase 1, the goal is to build a solid, injury-free foundation. This phase focuses on addressing any existing imbalances or weaknesses, particularly in your posture, core, and joint stability. We’ll start by rehabilitating any previous injuries and ensuring that your posture is aligned in its neutral position to promote efficient movement. Developing a strong core is also key at this stage, as strong abdominal muscles will improve your running form and endurance.
During this phase, we concentrate on the basic movement patterns: squat, hinge, push and pull. These fundamental movements are essential for building functional strength. Special focus will be placed on the hinge movement, as it closely mimics the running motion. Hinge exercises help to strengthen some of the muscles most engaged when you run, including the glutes, hamstrings and lower back.
In this phase, I will also perform a gait analysis to assess your running form. This allows me to identify any muscular imbalances or issues that might affect your running technique. Based on this analysis, I can adjust your strength training to address these imbalances.
Phase Two
Progressing into Phase 2, we focus on building more strength in single-leg exercises and developing more stability around the joints. At this stage, your body is ready to handle more targeted strength work, which will improve your running efficiency and reduce the risk of injury. We’ll gradually increase the intensity and load of the exercises.
Single-leg exercises such as single-leg squats, single-leg deadlifts, single-leg glute bridges and single-leg calf raises will be key components of this phase. These exercises challenge your balance and engage stabilising muscles in the legs, hips and core. They also help correct any muscular imbalances between your left and right sides, which is crucial for long-term injury prevention and optimal running form. For more information on these exercises, check out my 5 Key Leg Exercises for Runners.
In addition to single-leg strength, we’ll introduce plyometric training — if your body is ready for it. Plyometrics, such as pogos or bounding, help improve muscle elasticity, tendon stiffness and explosive strength. Research has shown that these exercises can enhance your running economy, making you a more efficient runner by reducing the energy cost of each stride. These exercises train your body to absorb and generate force more efficiently, making each stride more powerful while reducing fatigue over long distances.
Once you’ve mastered the single-leg movements and incorporated plyometrics effectively, you’ll be ready to move on to Phase 3, where we’ll continue to build on the strength and power you've developed.
Phase Three
This phase is all about increasing the intensity of your strength training, with a focus on heavier weights and more challenging movements. You’ll push your body to its peak strength in preparation for the demands of marathon running.
During this phase, we’ll progressively increase the weight and intensity of both bilateral exercises (movements that work both sides of the body at the same time, like barbell squats and barbell deadlifts) and advanced single-leg movements. Additionally, we’ll continue to include plyometric exercises, but at a higher intensity. Exercises in this phase will help improve your overall strength, as well as your explosive power - the ability to generate force quickly, which is key for a more powerful stride and faster running.
Once you've built a solid level of power and strength, we’ll shift focus in Phase 4 to tapering and maintaining your fitness as you approach race day.
Phase Four
In Phase 4, the focus shifts to maintaining the strength and mobility you’ve built while ensuring that your body is fresh and ready for race day. As your running mileage reaches its peak during this stage of marathon preparation, it’s essential to taper the intensity of your strength training sessions to avoid overloading your body.
During this phase, we reduce the load and volume of strength exercises; lighter weights and more mobility work become the priority. Exercises will be performed at a reduced intensity—using approximately 50–70% of the load you used during Phase 3. The goal here is to maintain your strength without adding more stress to your body.
In the two weeks leading up to the marathon, strength sessions will become even lighter. This final taper ensures that your body has time to recover fully while still staying prepared for the physical demands of race day. By the end of this phase, you’ll be well-prepared—both physically and mentally—for the big day.
Every runner is unique, so your strength training programme should reflect your specific needs. Factors like your fitness history, past injuries and mobility levels all play a role in determining the best approach.
Working with a personal trainer can help you create a tailored strength programme that complements your running schedule and minimises injury risk. If you’d like expert guidance, contact me, I would be more than happy to help guide you through the process!