Trading volume is a key indicator for identifying market trend reversals or continuations:

1. **Trend Continuation**:  
   - Rising volume during an uptrend or downtrend confirms strength.  
   - High volume breakouts suggest sustained momentum.  

2. **Trend Reversal**:  
   - Volume spikes during price consolidation may signal a reversal.  
   - Divergence between price and volume (e.g., price rising on low volume) indicates weakening trends.  

3. **Key Levels**:  
   - High volume at support/resistance levels validates breakouts or reversals.  

Analyzing volume alongside price action helps gauge market sentiment and predict potential shifts. Always combine with other indicators for accuracy.