This clip shows Jack Nicholson preparing for a scene in Stanley Kubrick's The Shining. In the scene, Nicholson's character Jack Torrance chops into a locked bathroom door to get to his wife, for whom he has a violent plan. To prepare for filming the scene, Jack gets amped up by jumping up and down in place like a boxer would, grabbing the ax and vocalizing.
The clip is from The Making of the Shining, which is a short documentary film made during production by Stanley Kubrick's then 17-year-old daughter Vivian. The documentary is packaged with The Shining Two-Disc Special Edition as a special feature. Another documentary about the making of the movie is Staircases to Nowhere: Making Stanley Kubrick's 'The Shining' by Howard Berry, which is a fantastic series of interviews of people involved with the film. The aforementioned Kubrick-endorsed documentaries, as well as the (previously featured at Neatorama) Room 237, make interesting viewing for any fan of Kubrick's horror masterpiece.