Some pull up variations working the back while also testing finger and grip strength (using both hands with one&two fingers each). The weighted pull ups are with +10 kg.
Repetitions need to be strict & controlled to keep the grip, trying to kick or swing will for sure be less comfortable :-)
For more pull up variations and exercises, See also my video:
TOP 10 Pull Up Exercises & Variations: Basic & Advanced
Other tips are:
Insane Norwegian Climber (by puffeboy) & How To Do More Pull Ups Program (Increase Your Reps!!) by barstarzz