The Support Phase bridges the gap between foundational aerobic development and race-specific preparation. If Base training establishes the fundamental aerobic “structure,” the Support Phase provides the physiological and mechanical reinforcements that allow an athlete to tolerate—and benefit from—the high-intensity, race-specific training that follows.
In practical terms, this phase enhances the load-bearing capacity of the aerobic system, neuromuscular system, and connective tissues. It is the period where the athlete shifts from “building capacity” to “preparing to express capacity.”
This is the phase of training to train.
During this phase (typically beginning 10–12 weeks before race day), athletes introduce more structured, purposeful workouts that target two major domains:
Running at moderately suprathreshold intensities enhances:
Recruitment of fast-twitch fibers under aerobic demand
VO₂ kinetics and oxygen delivery efficiency
Lactate clearance and buffering capacity
Neuromuscular coordination at higher velocities
Running slightly below race pace develops:
Economical stride mechanics at sustained effort
Glycogen sparing and improved fuel utilization
Enhanced stroke volume and aerobic power output
Greater resilience of soft tissues during prolonged loading
A typical Support Phase microcycle includes one session from each category per week.
The frequency established during Base training should remain unchanged. Maintaining frequency sustains aerobic signaling pathways, promotes connective-tissue remodeling, and reduces mechanical cost per stride.
Mileage increases continue, but at a much slower rate than in the Base Phase—approximately up to 20% total increase across the phase. The goal is to accumulate enough load to prepare the body for the Specific Phase, without compromising recovery.
As intensity increases, recovery becomes a performance variable. Sleep quantity should increase, and athletes should emphasize nutritional adequacy and low-stress easy runs. The objective is to ensure readiness for the higher mechanical and metabolic demands that are imminent.
Support training is often overlooked, yet it is one of the most impactful phases in long-term development. Just as adding a second level to a house doubles its functional space without increasing its footprint, the Support Phase expands an athlete’s adaptation capacity without requiring excessive mileage or extreme intensities.
It upgrades:
Tissue robustness
Metabolic adaptability
Neuromuscular efficiency
The athlete’s ceiling for future race-specific work
Without a well-developed Support Phase, the Specific Phase becomes much harder to absorb and risks exceeding the athlete’s structural and metabolic tolerance.