Analysis for basic weight training analysis?
I'd start with PCA to see the main correlations and maybe clustering. With the PCA you should be able to find nice sub-spaces, which you can plot and see, which parameters correlate the most/least. Clustering might help you identify "growth spurts". You might also try some linear regression to predict weight repetitions given the other parameters. Here I would be careful though, as the best predictor of performance will probably be the implicit 10th variable: time. You might want to tweak the regression problem to predict changes in performance given sleep, stress etc. In general, depending on what you are looking for, it might make sense to consider "change in repetitions" rather than the repetitions themselves. 

I hope this helps.