Truth Teller
Ostrich
Nascimento said:So what you're saying is that your knees were not meant to extend or flex.
I could see some damage being done if someone loaded 200lbs on the leg extension machine and heaved the weights; but assuming the person knows how to train properly, cite a source to support your claims.
I guarantee you more people injure themselves doing front squats and RDL's than they do with leg extensions and curls.
http://www.ncbi.nlm.nih.gov/pubmed/...tions+in+patellofemoral+joint+rehabilitation.
The leg extension places a ton of stress on the knees.