1. Introduction  
1.1. Star formation rate density at \( z>4 \)  
1.2. Main sequence and sSFR at \( z>4 \)  
2. Data  
3. Methods  
3.1. Stacking of the rest-frame FIR continuum images  
3.2. SFRD measurement: method description  
4. SFRD measurement results  
5. Star-forming main sequence and sSFR evolution  
6. Conclusions