Quote Originally Posted by Drummerboy
Copper functions in the oxidative deamination of specific lysyl residues in the soluble forms of both elastin and collagen. This process is essential for crosslink formation and the structural integrity of these proteins. While there is no evidence that nutritional iron deficiency results in connective tissue pathology, copper deficiency impairs crosslink formation and results in gross pathology of bones, lungs and the cardiovascular system of many animal species.

PMID: 6118903 [PubMed - indexed for MEDLINE]
I want to point to supplemental zinc (usually ZMA) use. The lack of adequate copper intake (1 part per 15 of zinc) could cause a copper deficiency, whose effect on tendons is pretty clear.
Men basically never experience iron deficiency, unless they are anemic.