The general development phase is the quiet core of successful preparation. It’s where you build the endurance, consistency, and strength that will help you handle heavier loads later. After the base phase and before specific race prep, this is where trail runners build their durability.
It’s a long, methodical, sometimes monotonous period — but absolutely essential. Without it, there’s no way to approach the rest of the season with confidence and performance.
Understanding the General Development Phase
This phase comes after recovery and marks the progressive return to structure and discipline. The goal: develop all the fundamental qualities needed for trail running — endurance, strength, and staying power.
For short to medium trail races (up to 60 km), this phase typically lasts 6 to 8 weeks. For ultras, it can extend up to 12 weeks.
The idea is simple: build a strong base of endurance and strength to serve as a launchpad for the specific training blocks to follow. Volume increases gradually, hill work is introduced, muscles are strengthened, and paces are tested. Nothing is left to chance.
Key Focus Areas
The guiding principle of this phase is variety. Each session serves a specific purpose.
Base endurance is the cornerstone. It takes up the majority of training time, at low intensity, on flat or gently rolling terrain. This calm, consistent work develops aerobic capacity — the foundation for going long without burning out.
Long runs come next, often on hilly terrain. They last 1.5 to 2 hours for mid-distance trail races, sometimes longer for ultras. These sessions build muscular endurance and teach pacing over time.
Hill work builds strength and power endurance. This is where the foundation for climbing is laid — with 1- to 2-minute uphill repeats or standing climbs on a bike.
Specific pace work (zone i3) helps build stability at a steady pace — simulating the effort required on race day.
VMA intervals and fartlek sharpen the cardiovascular system. These short, intense efforts (30 seconds to 3 minutes) remind the body to stay responsive.
To tie it all together, general strength training (core work, resistance exercises, proprioception) ensures body stability and helps prevent injuries.
Finding the Right Intensity Balance
The key to successful general development is load management. Coaches often refer to the 80 / 15 / 5 rule:
80% of volume at low intensity (easy endurance),
15% at moderate intensity (aerobic threshold, zone i3),
5% at high intensity (VMA, short intervals).
This ratio helps maintain freshness while encouraging deep physiological adaptations. You need to know how to run slow to get faster.
Sample Week Structure
Monday: Easy 45–60 min run on flat terrain. Nothing more.
Tuesday: Hill workout, e.g., 2 sets of 8 × 1-minute climbs, jog down to recover, followed by a short cooldown jog.
Wednesday: Light activity — cycling, swimming, or easy jog — to stay active without adding fatigue.
Thursday: Specific pace session: 20 min warm-up, 30 min at marathon or long trail pace, then cool down.
Friday: 30-minute strength session + 30-minute jog.
Saturday: The key session: 1.5 to 2 hours on rolling trails, walking if necessary.
Sunday: Rest or very easy jog.
This 6- to 8-hour weekly structure provides a solid base. More experienced runners can add a VMA session or extend the long run up to 2.5 hours.
Measuring Progress: The VMA Test
To fine-tune intensities, it’s essential to know your Maximal Aerobic Speed (VMA). A simple way to measure it is with the half-Cooper test.
The idea: run for 6 minutes at a steady, max pace on flat ground (track or road). Record the distance covered, then divide by 100 to get your VMA in km/h.
Example: 1,450 meters = VMA of 14.5 km/h.
This number helps tailor all your training paces:
Easy endurance: 60–70% of VMA
Tempo: 75–85%
Threshold: 85–90%
Long intervals: 90–95%
Short VMA: 100–105%
It’s a simple reference to guide sessions, avoid overtraining, and monitor progress month by month.
Adapting to Your Profile
If you’re just starting out or have a busy schedule, three sessions per week is enough: one long run, one hill or VMA session, and one easy run. The goal is to build consistency and a solid base without burning out.
Intermediate runners can aim for four to five sessions per week, balancing volume and intensity.
Advanced athletes may train six to eight times a week, sometimes with double sessions. For them, mastering the balance between intensity and recovery is crucial.
A Phase to Embrace, Not Endure
The general development phase is all about patience. On the surface, it may seem like nothing’s happening. But under the hood, everything is coming together — muscles grow more resilient, the heart becomes more efficient, and the mind more stable.
This is the time for quiet miles, the time to build the engine.
It’s not about chasing PRs — it’s about building the foundation.
Because every easy step you take now powers your performance later.