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 .
Hi, I just recently joined a gym Thursday and I went and got a personal trainer.
When I started my workout we basically focused on my biceps
and triceps. Friday morning I woke up in a serious amount of soarness in my arms to the point where I could not bend my arms nore do any of my daily activities. I had been taking ibuprofen for the extreme soarness. It is now Sunday and I can feel some soarness giving up but my arms are still killing me. I don't think I tore anything, I just believe I'm soar. What are your suggestions on what I should do?