Ever felt like your strength sessions are sabotaging your running legs? You’re not alone. Many runners skip the gym or squeeze in a short session during the off-season. The most common fears? “I’ll bulk up”, “It’ll ruin my endurance”, or “My legs will feel heavy for days.” The solution is periodisation.

The truth is: it’s not the strength training that causes the problem, it’s the timing and structure of it. When you periodise, plan, and align your strength work with your running phases, it becomes one of the most powerful tools for improving endurance, resilience, and speed.

Periodisation is the structured, evidence-based sequencing of training across the year. The goals are the reduce injury risk by balancing training load and recovery, optimise performance by targeting the right fitness qualities in each phase and sustain progress. It also considers real-life factors such as work stress, recovery, and nutrition.

The Science of Periodisation

Think of periodisation as constructing a house: you lay the foundation first, strengthen the frame, and only then add the finer detail that makes it perform beautifully under pressure. In training terms, this means structuring your year into a series of planned cycles, each with a specific purpose, like running. Macrocycle is your overall yearly plan, outlining the progression from base training to peak performance. Mesocycles are medium-term blocks (typically 4-8 weeks) focusing on key qualities such as endurance, strength, or power. And microcycles are short-term weekly plans that dictate the details, individual sessions, loading, and recovery days.

Athletes progress through four key phases during the year: the general preparatory phase, the competitive phase, the peak phase, and active rest. Each phase develops specific qualities and aligns with its goals and competition schedule.

Training Phases Explained: From Foundation to Peak

During the general preparatory phase, the primary focus is on building a foundation. Training volume is higher, and intensity is moderate, allowing athletes to develop work capacity, foundational strength, and technical proficiency.

For less experienced runners, this phase is dominated by high-force, low-velocity (HFLV) lifts, such as squats, deadlifts, lunges, and posterior chain exercises. These movements improve tendon stiffness, movement efficiency, and muscular resilience. For more advanced athletes, the emphasis remains on maintaining volume, but the movements can be more sport-specific and technical.

As athletes transition into the Competitive Phase, training becomes more specific. Volume is gradually reduced while intensity increases, and the focus shifts towards maximal strength and power development. This is the stage where explosive, low-force, high-velocity (LFHV) exercises are introduced, including plyometrics, short sprints, and Olympic lift derivatives. These exercises enhance the rate of force development and refine running economy, translating the strength built in the preparatory phase into faster, more efficient movement.

The Peak Phase is where all the preparation comes together. Training load is reduced to allow accumulated fatigue to dissipate, but intensity remains relatively high to preserve neuromuscular sharpness. Sessions are shorter and highly focused, avoiding new or unfamiliar exercises that could cause soreness or compromise performance. The goal is to feel fast, responsive, and powerful as the athlete enters key competitions.

Finally, the Active Rest Phase provides a period of recovery and regeneration. Training volume and intensity are significantly reduced, and athletes engage in light, recreational activities that maintain movement quality without adding fatigue. Light maintenance strength sessions, perhaps once per week, preserve neuromuscular adaptations and ensure that the athlete can return to the next macrocycle prepared to rebuild their base.

Sequencing training this way allows runners of all levels to progress safely through the strength-endurance, basic strength, strength, and power phases. Each quality is built in a deliberate order. The key principle is that every phase should build on the previous one. This approach potentiates adaptations while dissipating fatigue. It ensures that strength work enhances running instead of detracting from it.

Why Heavy Lifting Still Matters for Runners

Despite common misconceptions, heavy lifting is not about bulking up; it’s about building functional strength that directly improves running performance. Research consistently shows that lifting loads above 70% of one-repetition maximum enhances running economy, power, and fatigue resistance. It does this without significantly increasing body mass. Heavy strength work also increases musculotendinous stiffness. This allows muscles and tendons to store and return elastic energy more efficiently, lowering the energy cost of each stride. Stronger legs enable faster recruitment of high-threshold motor units. They also improve the force–velocity and force–power curves, helping runners generate force quickly and sustain pace or sprint effectively in the final stages of a race.

From a physiological perspective, heavy strength training benefits both low-intensity and high-intensity endurance performance. When combined with regular endurance training, HFLV work boosts maximal strength, rate of force development (RFD), and the “anaerobic reserve.” This reserve allows runners to summon extra power for a finishing sprint or maintain speed during the final stages of a race. Research comparing heavy and light strength loads consistently shows that heavier training improves running economy, sprint capacity, and overall endurance more effectively. Even lighter, high-velocity (LFHV) training, using less than 40% of 1RM and including plyometrics or short sprints, still applies substantial forces. These forces provide meaningful adaptations, improving 5k times, running economy, and sprint performance.

summary

Combining heavy, explosive, and endurance work without proper periodisation may dilute adaptations, limiting gains in strength, power, or endurance. A structured, periodised approach helps the body build a foundation and ensures that each adaptation fully realises its potential and transfers directly to performance.

If you’re looking for a structured strength programme, I offer an 18-week strength training plan that guides you through each training cycle. It’s perfect if you’ve never periodised your strength work before or if you’ve been repeating the same routine year after year. For a full-year periodisation plan or personalised coaching to optimise your training, send me an email and let’s discuss how I can help you reach your running goals.

Bazyler, Caleb & Abbott, Heather & Bellon, Christopher & Taber, Christopher & Stone, Michael. (2015). Strength Training for Endurance Athletes: Theory to Practice. Strength and conditioning journal. 37. 1-12.