You need a Jacquard meat tenderizer http://www.jaccard.com/
available from amazon and other places. However mechanical tenderising can only have a limited effect,
When meat cooks there are 6 separate processes:
1 Enzymatic tenderising (which is what happens slowly when meat is hung). Enzymes are deactivated above 65C
2. Protein degradation. The muscle proteins degrade with heat and curl up into tight stringy spirals, squeezing out the juices, This happens from about 60C to about 65C
3. Oxidation of myoglobin, The red pigment turns to grey at about 60C
4. Collagen (the tough bit holding the muscle fibres together) dissolves to gelatin. Braising steak has lots of collagen, but the gelatin gives good mouth feel. This reaction is temperature dependent, but happens from about 50C (slow) to about 75C (fast). Thus in a stew tough meat is cooked in a hot wet environment to give tender meat (the collagen dissolves) but stringy (the protein has coagulated)
5. The fats melt at various temperatures from 44C upwards
6. Pathogens such as e.coli are denatured depending on time and temperature from 89 minutes at 55C to 14 seconds at 70C internal temperature. Time for conduction of heat through the meat must be allowed for in calculating pasteurization times. However the inside of a solid piece of meat is fairly sterile provide it has not been spiked by anything such as a knife, Jacquard meat or mince or hamburger is not
7. The outside is browned (Maillard reactions) by high heat.
So for the tenderest steak ever sear the outside over high heat, then cook at 56C +/- 0.5C (for rare) for 24 hours.
For more (lots more) see http://modernistcuisine.com/
by Nathan Myhrvold