Comments: This is a very exciting area for improvements in manufacturing generally. Some Rapid Prototyping software and devices are maturing to the point where it is starting to become possible in the near future that we will be telling computers to “make a basketball” or “make a fuel injection system.” Pardon the reference to Star Trek, but some of the equipment we have seen begins to resemble the “Replicator” technology that sits on most countertops (much like a microwave), in the crew quarters on the Starship Enterprise.
Glad you asked here, because the meat heads at a lot of the bodybuilding forums would flip if you wanted to look slim and lean like Taylor Kitsch. The ladies dig this look and it works well in hip clothes, etc. Good goal. So his physique is built a lot more on low body fat vs having to add a lot of muscle. I would suggest a low volume of strength training and crush the heck out of it on HIIT. When in doubt, less lifting and a little more intervals. Keep those calories down. If you are 6′ tall and want this look, you will probably have to hit the 160 pound mark (with his level of muscle). So work on dropping roughly 15 pounds of fat. It will take you until sometime in June if you work hard now. Sound good?
The efficiency of human muscle has been measured (in the context of rowing and cycling ) at 18% to 26%. The efficiency is defined as the ratio of mechanical work output to the total metabolic cost, as can be calculated from oxygen consumption. This low efficiency is the result of about 40% efficiency of generating ATP from food energy , losses in converting energy from ATP into mechanical work inside the muscle, and mechanical losses inside the body. The latter two losses are dependent on the type of exercise and the type of muscle fibers being used (fast-twitch or slow-twitch). For an overall efficiency of 20 percent, one watt of mechanical power is equivalent to kcal per hour. For example, one manufacturer of rowing equipment calibrates its rowing ergometer to count burned calories as equal to four times the actual mechanical work, plus 300 kcal per hour,  this amounts to about 20 percent efficiency at 250 watts of mechanical output. The mechanical energy output of a cyclic contraction can depend upon many factors, including activation timing, muscle strain trajectory, and rates of force rise & decay. These can be synthesized experimentally using work loop analysis .