Constant Flux in Action

In a world where athletes constantly search for new and improved training methods, flux training remains a highly effective yet underutilized approach. This dynamic training method, which involves fluctuating efforts and natural pace changes, could be the key to unlocking better performance in sports like swimrun, where constant adaptation to changing conditions is crucial.

The Evolution of Flux Training: A Blend of Tradition and Innovation

Few training concepts are as timeless and effective as fartlek training. Developed in the 1930s by Swedish coach Gösta Holmér, fartlek, which means "speed play" in Swedish, was designed to mimic the unpredictable nature of racing. Athletes would vary their pace, blending hard efforts with recovery, all within the same workout. This not only built speed and stamina but also helped runners develop adaptability, a crucial skill in races where terrain and competition could force sudden shifts in pace.

Over the years, fartlek influenced training programs worldwide, from Arthur Lydiard's varied intensities in New Zealand to interval-based workouts in Eastern Europe. However, as sports science advanced in the late 20th century, Western running culture shifted towards more rigid, data-driven training methods. With the rise of GPS watches, heart rate monitors, and planning tools like Training Peaks, athletes, and coaches became focused on hitting exact paces, often at the expense of the natural variability inherent in racing.

A Deeper Look at Flux Training

Recently, modern coaches like Steve Magness have reintroduced flux training into running culture, emphasizing the need to replicate the real-world dynamics of races. Flux training involves alternating intensities within a single workout, allowing athletes to adapt to changing race conditions like surges from competitors, varying terrain, or even environmental factors like wind or heat.

Magness argues that while precision and pace-based training can improve fitness, it doesn't always prepare athletes for the unpredictability of race day. By incorporating flux-style workouts, athletes can train their bodies and minds to handle fluctuations in intensity, just as they would experience in a race.

East African Success: The Power of Intuitive Training

In contrast to the structured, pace-based training seen in the West, East African runners, particularly from Kenya and Ethiopia, have long incorporated flux principles into their training, albeit more intuitively. Group runs, varied terrain, and an emphasis on feel-based pacing dominate their training culture.

1. Group Running and “Follow-the-Leader” Style: East African athletes often train in groups, with the leader setting the pace. The pace fluctuates naturally based on terrain or how the leader feels, forcing runners to adapt to constant changes in intensity.

2. Varied Terrain: Many East African runners train in hilly areas like the Rift Valley, where the rolling terrain causes constant shifts in effort, mimicking the dynamic demands of a race.

3. Effort-Based Training: Rather than adhering to specific target paces, these athletes focus on how they feel during a workout. This intuitive training builds adaptability and endurance—essential qualities for racing.

This organic approach to training has contributed to the dominance of East African runners in distance events, especially those that require frequent surges and pace changes.

Mount Entoto is a highland region located just north of Addis Ababa. The forested hills of Entoto provide a challenging environment for endurance training, with rough terrain and steep inclines, which are favored by runners to build strength and stamina. Check out the book Out of Thin Air by Michael Crawley for fascinating insights into Ethiopian running culture.

Lessons from Swimming and Cycling: The Norm of Constant Flux

While running has moved away from flux training, other endurance sports have consistently embraced these principles.

• Swimming: Swimmers often train using intervals that alternate between harder laps and recovery laps. This variation in effort builds both aerobic capacity and lactate clearance, similar to fartlek training in running. Swimmers must also switch between strokes, adding another layer of variability to their workouts.

• Cycling: Cyclists frequently face fluctuating intensities during training, particularly in road races where hills, wind, and tactical surges are common. Training for these variations requires constant adjustment to power output, much like flux-style training in running.

Flux Training and Swimrun: A Perfect Match

Swimrun, by its very nature, is a sport built on adaptability. Whether transitioning from a steep trail run to an open-water swim or climbing hills and descending technical terrain, athletes face constantly changing intensities. Flux training is the ideal preparation for swimrun's unique demands, offering the following benefits:

1. Improved Pacing Control in Unpredictable Conditions: Swimrun courses are notorious for their unpredictability. Athletes must adapt to changing terrain, weather conditions, and varied distances between running and swimming legs. Flux training teaches intuitive pacing, a crucial skill in swimrun, where external factors often impact performance.

2. Enhanced Lactate Tolerance and Recovery: Swimrun races often push athletes into their anaerobic zone during intense running sections. Flux training, which alternates between hard efforts and recovery, helps build lactate tolerance and teaches the body to recover on the go. The swim sections of a race, with their lower heart rate demands, offer a natural recovery opportunity similar to the recovery segments in flux training.

3. Mental Resilience and Adaptability: One of the biggest challenges in swimrun is the mental resilience needed to handle constant transitions between running and swimming. Flux training develops mental toughness by incorporating frequent changes in effort, forcing athletes to stay engaged and adaptable throughout a workout.

4. Balanced Development of Muscular and Cardiovascular Endurance: Swimrun requires both anaerobic power and aerobic endurance. Flux training alternates between these demands, ensuring athletes develop both systems in a balanced manner.

Final Thoughts: Embrace the Flux

Swimrun demands constant adaptation to changing intensities, making flux training an ideal preparation strategy. By incorporating varied efforts and dynamic pacing into their training, athletes can build the endurance, pacing control, and mental resilience required for swimrun success. 

So, embrace flux training—because just like a swimrun course, or indeed life - nothing stays constant for long.

Trail Running in Grimsta - Photos by @martinsuper