Ness and Paton (1979) experiment. Beginner weightlifters lifted 7-9 kg (20 lbs) more weight on incline bench press than they "actually can". How? They were told that they are lifting the weight they are capable of lifting and didn't know that researchers actually put more weight on the bar than they led participants to believe. You might be thinking "They are just beginners, it is not strange that their strength goes up fairly quick". But look at Mahoney (1995) experiment results - even OLYMPIC WEIGHTLIFTERS, who didn't know what weight they were lifting (and actual weight on the bar was higher than they usually can lift), improved their personal records and some lifters increased their snatch by as much as 20 lbs+.
Ariel and Saville (1972) experiment. Participants were lifters who have regularly trained for years before the experiment. First phase was 7 control weeks (during this phase there was no intervention - it was used to see how much strength lifters will gain while training as they usually do). Second phase - 4 weeks with "steroids". During those 4 weeks participants there given "steroids", which were actually placebo pills.
RESULTS: During 7 control weeks lifters increased their lifts on average by:
- Bench press + 4,54 kg (10 Lbs)
- Overhead press + 0,73 (1,5)
- Sitting military press + 2,27 (5)
- Squat + 2,65 (6)
- Overhead press + 0,73 (1,5)
- Sitting military press + 2,27 (5)
- Squat + 2,65 (6)
RESULTS: During 4 weeks "on steroids" lifters increased their strength on average by:
- Bench press + 13,28 kg (30 lbs)
- Overhead press + 7,59 (18 )
- Sitting military press + 5,30 (12)
- Squat + 18,94 (42,5 )
- Overhead press + 7,59 (18 )
- Sitting military press + 5,30 (12)
- Squat + 18,94 (42,5 )
Maganaris, Collins, Sharp (2000) experiment. Participants - 11 powerlifters, who have been training for a couple of years. Participants increased each of their powerlifts on average by 10 kg (20+lbs) (total was about 60lbs+ increase in strength). You might be asking "How long did it take to get these results?" The answer is... 10 minutes! It is not a typo. This result was achieved in 10 minutes. Participants were given "fast working anabolic steroids" (which were actually placebo) and after ten minutes they got gains, which usually take months and years for experienced lifter to achieve.
And remember, information written above is not anecdotal evidence, this information is based on SCIENTIFIC RESEARCH. Of course, scientific experiments have their own biases and limitations, and obviously they are not something that "can't be touched". But they still are more reliable source of information than anecdotal evidence and you can also use them in your own academic research.