diff --git a/app/views/api/trainings/index.json.jbuilder b/app/views/api/trainings/index.json.jbuilder
index 72ff1ff85..02cdd42b4 100644
--- a/app/views/api/trainings/index.json.jbuilder
+++ b/app/views/api/trainings/index.json.jbuilder
@@ -1,19 +1,13 @@
-json.array!(@trainings) do |training|
-  json.id training.id
-  json.name training.name
-  json.description training.description
-  json.machine_ids training.machine_ids
-  json.availabilities training.availabilities do |a|
-    json.id a.id
-    json.start_at a.start_at.iso8601
-    json.end_at a.end_at.iso8601
-    json.reservation_users a.slots.map do |slot|
-      json.id slot.reservation.user.id
-      json.full_name slot.reservation.user.profile.full_name
-      json.is_valid slot.reservation.user.trainings.include?(training)
-    end
-  end if attribute_requested?(@requested_attributes, 'availabilities')
-  json.nb_total_places training.nb_total_places
+role = (current_user and current_user.is_admin?) ? 'admin' : 'user'
 
-  json.plan_ids training.plan_ids if current_user and current_user.is_admin?
+json.cache! [@trainings, role] do
+  json.array!(@trainings) do |training|
+    json.id training.id
+    json.name training.name
+    json.description training.description
+    json.machine_ids training.machine_ids
+    json.nb_total_places training.nb_total_places
+
+    json.plan_ids training.plan_ids if role === 'admin'
+  end
 end