RVOL helps distinguish true index trend extensions from normal pullbacks by measuring participation behind the move; different logic tiers can classify price action as exhaustion, continuation, or mean‑reversion. For indices, you can combine intraday RVOL with structure (higher highs/lows or lower highs/lows), volatility regimes, and key reference levels (prior day high/low, VWAP, session open) to define extension vs. pullback conditions.