[Q.]

I really liked the newsletter article on the 300 workout so I shared it with a grad student who also works at our campus gym where I go. Here were his comments:

That looks like a pretty cool workout. The only exception I would have is the floor wiper. I personally do not think that is very safe exercise (especially for those who have muscle imbalances in the core) because of what happens between the sacrum and lumbar vertebrae. You have half your body weight twisting and flexing at this joint which places a lot of pressure in that one spot. If you have a weaker lowerback or abdominals your body is forced to overcompensate by unevenly distributing the weight through the lumbar sacral region placing you at a high risk for injury. I would approach this particular exercise with extreme caution. Especially if you’ve have low back pain or had at injury to your lower back.

He knows I have issues with my lower back (although it's been feeling much better since I resumed deadlifts!) so he may have been intending that particularly for me. Do you agree with his assessment?