Apex Run monitors your weekly work accumulation to help you build endurance safely. By analyzing the relationship between short-term training fatigue and long-term fitness baselines, the app helps you balance recovery and progression.
1. Training Load#
- Definition: A rolling measure of how much stress your training is placing on your body, based on workout intensity (pace/GAP) and duration over recent weeks.
- Load Trend: The direction your overall load is moving. Gradual increases of 10% or less per week are generally safe, while sharp spikes dramatically raise injury risk.
2. ACWR (Acute:Chronic Workload Ratio)#
- Definition: The core model Apex Run uses to evaluate whether your training volume is increasing at a healthy rate.
- Acute Load (last 7 days) — Represents current training fatigue.
- Chronic Load (last 28 days) — Represents your long-term fitness baseline.
- Calculation:
ACWR = Acute Load ÷ Chronic Load
The ratio flags whether you are training in the optimal “sweet spot” or pushing into zones that increase injury risk:
| ACWR Range | Zone | Meaning |
|---|---|---|
| 0.8 – 1.3 | 🟢 Productive | Sweet Spot. Acute load is slightly above chronic—stimulating aerobic adaptation while minimizing injury risk. Maintain current rhythm. |
| 1.3 – 1.5 | 🟠 High Exertion | Functional Overreaching. A significant breakthrough attempt. Monitor closely; follow with a dedicated recovery week. |
| > 1.5 | 🔴 Overreaching | Danger Zone. Weekly load increased too fast (>150% of your long-term average). Rest or reduce training volume immediately. |
| < 0.8 | 🔵 Recovery | Detraining / Recovery. Recent load is well below your habitual level. Good after a major race, but long-term maintenance causes detraining. |
Note
The current version of Apex Run calculates training load based on distance. Short high-intensity runs (like track intervals) may be slightly underestimated. Heart-rate-based load (TRIMP) is planned for a future app version.
See also:
- Training Zones — Heart rate zones and pace zones in detail.
- 80/20 Training Structure — How to balance your training load across intensity levels.
- Performance Metrics — VO2 Max, Running Power, GAP, EF, and PSI.
- Running Form Metrics — Cadence, stride length, ground contact time, and other technique measures.