1. In this study they don't give a placebo. This makes the study flawed since belief can change performance. Additionally, they don't give actual numbers in the abstract indicating what they actually consider "significant". "Significant" could mean anything. The total number of participants was small as well.
2. Good, they did a placebo. However, they gave no quantities to compare. And the total number of participants was small. We know that creatine causes an increase in water weight. How do we know that the protein didn't cause in increase in "lean tissue" by an increased amount of undigested in the digestive system? Also, how reliable was their method of measuring "lean tissue"?
3. Casein is a slow digesting protein compared to the others. How do we know the increase in FFM wasn't due to an increase of undigested food in the digestive system?
4. What are they referring to as "lean tissue"? Again, how do we know it isn't just undigested food in the digestive system? How do we know there wasn't any sodium in their supplements, that which would cause an increase in LBM due to a retention of water weight?
I don't think you can conclude anything from those abstracts alone.
But this makes me wake up and realize something else. What about the studies sited by Brad Pilon? When you're reading a book, it's a lot easier to just accept what the author is saying just to make it easy reading. In reality, I'd have to look at those studies as well.
However, I can comment from my own personal experience. Glycogen, creatine, and calories are all factors that seem to make a difference in strength. But I don't think that decreases in muscle actually happen that fast. I've lost a lot of weight. I've fasted many times, even up to 4 days. I lost strength due to the weight loss. But then it comes back quick as soon as I start eating more. To me that's an indication that I've only lost strength temporarily due to a lack of energy, but I didn't lose any muscle.
Those studies actually remind me of the studies that Arthur Jones was siting that he was using to promote his ideas of doing one one set to failure. His claim was that the difference in strength increases from 1 set or 3 sets were insignificant. However, when I actually looked at the numbers and did the math, my calculations were that such "insignificant" strength differences add up over a year. So to me, yes, 3 sets delivers more significant strength increases than 1 set.