Hitting exercises are perhaps a trademark of Lowenian bioenergetics. A standing participant raises a tennis racket overhead and slams it down flat against a mattress or bed. Some attention by the participant or a coach is paid to using the entire body and voice so as to help unify the expression, but not so much correction or self-consciousness as to stifle all spontaneity. A tennis racket has the advantages of achieving convincing velocity, causing a convincing sound, having little dangerous recoil, and feeling solid in the hands. One large clasped fist of two hands can be used, this is harder to coordinate and may hurt the hands. A baseball bat can be used to add even more realism and a solid feel, although the danger of bounce back and accidentally letting go exist, and a bat can damage the mattress over time. Foam batakas seem ill-suited to this exercise if one understands it as neuro-muscular retraining.
This exercise is meant to originate from the shoulder blades or lower on the back. It is a great complement to towel twisting exercises that use the grip and arm muscles more. In folk practice, chopping wood has fulfilled this purpose, but sharp instruments and emotions should not mix.
Rationale: As I understand it, the most fundamental purpose of this exercise is to loosen the muscles between the shoulder blades (rhomboids, latissmus dorsi, teres major and minor, lower trapezius, and spinal erectors) where anger is blocked. This slowly 'frees up' anger and reaching as spontaneous real-time expression in relationships. Of course several other uses are made of it: 1) catharsis of anger, 2) abreaction of memories, 3) 'raising energy, 4) priming the pump of anger, 5) communicating to an audience how angry one is or how angry one believes one should be, and 6) rehearsing an assertive attitude for later use. The latter two uses are perhaps not intrinsically misguided, but they may actually take the participant out of his or body, being performance oriented.
Source: Alexander Lowen (although commonly spontaneously and independently invented by frustrated individuals) Lowen's great contribution is to employ it consistently and sometimes when the participant did not 'feel' like it.