A recent meta-analysis and systematic review showed that from the studies included that ashwagandha seems to increase both strength and power moderately and endurance performance greatly. Can someone explain why this has not been brought up, since the effects of the supplement seem high based upon a meta-analysis with 8 studies for strength and power and 8 studies for endurance performance? I do realize that one of the authors that accessed risk of bias works for a company that sells ashwagandha, but from my understanding the analysis seems sound.
Here is the link to the meta-analysis (free access):
I’m not sure what you mean when you ask “why this hasn’t been brought up”, but I don’t think the data is very solid on ashwaganda just yet. It’s been investigated for nearly everything under the sun and between the methodology, confounding variables, and somewhat unreliable findings, it’s not something I think has a notable positive effect just yet. As more data emerges, this position may change and It’s something I keep looking into.
I definitely jumped the gun after seeing the effect sizes reported in the meta-analysis attached. I realized after looking at the studies included in the section about strength and power that only one of the eight studies actually accessed strength in the barbell movements while being well-controlled. Regarding the results on endurance performance (VO2max), would you recommend ashwagandha for an endurance athlete?
It seems as if the results in this regard are more specific (than for strength and power) and a bit better controlled.
The effects also seem to be incredibly high, standardized effect size of 1.89 (CI(1.3-2.51)). This effect seems huge for a relatively cheap supplement, considering meta-analyses on creatine find effect sizes of around 0.3 for strength.
Yea I think this is more of a GIGO (garbage in garbage out) type of meta here and I think we need to be very careful in how we interpret them and guide management. I also don’t think the effect size should make your eyes light up.
Creatine works about 2/3 of the time and can yield larger results than any paper cited in this meta for ashwagandha. Still, even it is probably going to make a huge difference for the average person who resistance trains
ES must be looked at through the actual data being cited, not just as the number on their own. Regardless, creatine does appear to work. Ashwagandha, I’m not as confident yet. You may feel differently.
Regardless of the effect sizes do you have some literature at hand you can throw my way regarding the fact that 2/3 of people seem to respond to creatine? The normal citation i see in the literature is a study by Syrotuik and Bell, showing 1/3 being “responders” 1/3 being “quasi responders” and 1/3 being “non responders”. The big caveat to me seems to be the case that the study involved 11 participants, which seems a bit low to infer to the general population.[/QUOTE]
As far as the study on responders, that’s the one that’s often cited. It’s pretty cool that they did some tissue level analysis to correlate it to performance. Yes, there are additional data investigating performance outcomes in those being supplemented with creatine and showing differential results, but not correlating them to tissue level cr-p levels, AFAIK.