Fu et al. [1] have reported an interesting set of experimental results on ultra- high molecular weight (UHMW) polymer fibers. The characterization techniques used in their study are primarily x-ray diffraction,13C solid-state nuclear magnetic resonance (NMR), and differential scanning calorimetry (DSC). We do not comment on the specific results reported using these techniques, but make some comments regarding statements on other techniques not employed by these authors (i.e., Raman spectroscopy and theoretical simulations), as well as several more general comments.