Sub Ajout()
Dim I&
Application.ScreenUpdating = False
With Sheets("Sheet1")
For I = .Cells(.Rows.Count, 1).End(3).Row To 2 Step -1
If IsNumeric(.Cells(I, 8).Value) And .Cells(I, 8) > 1 Then
.Rows(I).Copy
.Rows(I).Resize(.Cells(I, 8).Value - 1, 1).Insert Shift:=xlDown
End If
Next I
End With
Application.ScreenUpdating = True
End Sub