What are Impacts?
Impacts is the first objective physical contact metric available in OLIVER PRO for rugby. The system automatically detects, counts, and classifies the contacts each player receives during a match or training session — tackles, rucks, mauls, and collisions — using the OLI dorsal sensor already included in the kit.
No additional setup, cameras, or manual staff work required. At the end of the session, the performance coach can see the number of impacts per player and their classification by intensity.
Impact classification
Each detected impact is assigned an intensity band based on the recorded acceleration:
Low (8–10G) — Sustained pressure: ruck, maul, held contact
Medium (10–12G) — Direct tackles and clear collisions
High (12–15G) — Hard tackles, impact falls
Very high (>15G) — Severe impacts — the most intense of the session
Same match, two different players
Two players who played the same minutes can accumulate completely different contact loads. Here is an example of what the data looks like:
Player A: 54 total impacts — 8 at very high intensity. At the center of contact throughout the match.
Player B: 10 total impacts — 2 at very high intensity. Few and moderate contacts.
Player A received four times more severe hits than Player B. Without this metric, that difference was invisible to the coaching staff.
Impact volume ranges from 10 to 54 per session depending on position and role. A forward with 21 total impacts but 6 at very high intensity can represent a completely different risk profile from a player with 54 low-intensity impacts.
How the sensor works
The OLI records trunk acceleration and rotation at 27 samples per second throughout the entire session. Processing follows four stages:
1. Continuous recording — The sensor captures trunk acceleration across three axes for the full duration of the session.
2. Peak detection — The algorithm identifies moments where acceleration rises sharply. Normal running or jumping has a different signal profile and is automatically discarded.
3. Rotation validation — Every real impact also generates trunk rotation. If the sensor does not detect coherent rotation at the same time, the event is discarded — it is not an impact, it is noise.
4. Classification — Each confirmed impact receives its intensity band: low, medium, high, or very high.
Scope of the metric
The Impacts metric reliably captures:
The total number of impacts per player per session, classified by intensity band
Differences in contact load between players in the same match
Players who systematically accumulate more high-intensity hits than their teammates
Contact load variations across weeks — for example, double-match weeks versus regular weeks
Sessions played both indoors and outdoors — no active GPS or additional calibration required
What's coming next
Post-impact recovery time — Measuring how long it takes a player to recover 70% of their activity level after receiving an impact. An objective recovery indicator that can flag hits that are more serious than they appear.
Scrum detection — The scrum has a fundamentally different contact profile from a tackle or ruck and requires its own detection model. Currently under active research.
💡 Pro tip
Combine the Impacts metric with high-intensity distance (>85% of maximum speed) to get a complete picture of each player's effort — both locomotor and contact demands. This is especially useful during double-match weeks or preseason periods with frequent scrimmages.