I'm currently writing my thesis and was wondering which statistical method is best suited for my research question. We're investigating if different anthropometrical and neuromuscular characteristics of a runner (such as leg length, muscle strength, independent variables) can explain the biomechanical difference while running in two different running shoes. So to clarify, we've studied the difference in running mechanics while running in two different shoes and now we want to examine if any of these independent variables can explain the difference.

We've been discussing both multiple regressionanalysis as well as ancova and repeated measures mixed model ancova, with the independent variable as a covariate. I'm just afraid that ancova for instance doesn't really answer the question "explain the difference" and that we can really see how much the different variables affect one another in conjuction with the outcome variable.

PS: We have a very small sample size of 8 runners.

Appreciate all the help I can get, and just let me know if I need to clarify anything further.