“Muscle balance” might be important… but we do not have the science! More specifically: we have the science, but it’s too much of a mess to be informative.
Guan et al is a conclusively inconclusive new review of 28 trials of inter-limb asymmetries (e.g. hamstrings:quadriceps ratio, their relative strength, power, etc). There’s plenty of decent data here … but, as the research folks say, it is “heterogenous.” Soooo heterogenous. All measuring different stuff in different ways.
“Inconclusive” is never anyone’s favourite result. 😕 But it is good for confirming that most ideas about inter-limb asymmetries are guesses… not evidence-based.
I’ve just cited Guan et al. in my muscle strain book, a minor update to the muscle balance chapter. I delve into “muscle balance”: how much it might matter, and whether we can do anything about it.