-form_for @resistance, :action => url(:resistances) do
  %p=text_control :name, :label => "Exercise"
  %p=text_control :when, :label => "When"
  %fieldset
    %legend Sets
    -@resistance.exersets.each do |exerset|
      .set
        %p=text_field :name => "resistance[set_attributes][][repetitions]", :label => "Reps", :value => exerset.repetitions
        %p=text_field :name => "resistance[set_attributes][][weight]", :label => "Weight", :value => exerset.weight
    %button.another Another
  %p=submit_button "Add"