Participation happens on three levels.
First, it means being physically present at the celebration of the Liturgy.
Second, it means taking part actively with all our senses: in the prayer, proclamation of the Word, and the song. Liturgy should be sung!
Third, that ’active’ participation is a portal. Through that active sharing in the ritual act, we are called to change inwardly.
The aim of participation isn’t singing, sitting and standing and so on, but conversion of heart. From ‘active’ participation we should be moving to an attentiveness and to a contemplation of Christ who by the power of the Holy Spirit, is the principal actor in the Liturgy, as ‘High Priest.’ So ‘active participation’ should lead to ‘interior participation.’ You can’t separate the two.