Compared how? On an absolute strength basis? Normalized to body weight? Normalized to fat-free weight? Normalized to muscle cross-sectional area? In my opinion, only the latter basis would be a fair starting point for a comparison. And it would require CT or MRI to obtain those cross-sectional areas.

Agreed. Strength normalized to PCSA of the muscle tissue would be the best comparison. These data exist for isometric and concentric muscle actions, but I'm unaware of any data which have examined this during eccentric muscle actions.

Physiological cross-sectional area is not easily determined for humans. For each subject, you have to know muscle mass, average fiber length, and the pennation angle in order to calculate PCSA, i.e., all things not easily determined. It is more practical to normalize strength to anatomical cross-sectional area, which can be determined directly through imaging. Even after you normalize to CSA, how do correct for differences in training among subjects? One would intuitively expect obese subjects to be less well-trained than non-obese subjects. I would expect the % muscle activation during a MVC for a less well-trained person to be less than that for a well-trained person, especially in the knee extensors.

Data from interpolated twitch experiments agree with this (decreased voluntary activation) and decreased strength per CSA or muscle volume.

I'm not aware of any study to have compared either absolute or normalised eccentric strength/power in obese or lean adults in humans, nor have I seen any isolated muscle models to better measure muscle quality during eccentric muscle activity.

My colleagues and I at Coventry University are currently preparing a manuscript comparing young (~20 weeks) lean and dietary-induced obese whole, isolated, mouse soleus and EDL during eccentric muscle activation using the work loop technique. By directly measuring muscle mass, we are removing the above mentioned difficulties in measuring force/power relative to muscle CSA.

We compared absolute concentric & eccentric power, concentric & eccentric power normalised to muscle mass and fatigue resistance to a sustained bout of 50 concentric or 50 eccentric work loops.

I currently don't have access to the data or the manuscript, so I can't give any insight into the findings as of yet, but our paper is looking to answer your question (at least, in isolated mouse muscle!). Once I've had a look at the paper again I will be happy to discuss. The muscle testing protocol used is identical to a paper we published in The Journals of Gerontology, Series A (Hill et al. 2018) comparing young (10 weeks) and older (78 weeks) soleus and EDL, which I'm happy to send to you in the meantime.

Thanks, Cameron. I look forward to seeing these data when they are published!