Aerospace engineers design aircraft, spacecraft, satellites and missiles, according to the BLS. In addition, these engineers test prototypes to make sure that they function according to plans.
1 Try a deload every six weeks or so. 2  Most serious coaches recommend three or four weeks on, one week off to their intermediate and advanced trainees. 3  These are people competing in strength sports and pushing serious weight, so you may not have to deload quite so often.
Limits on the number of cortisone shots. There's concern that repeated cortisone shots might cause the cartilage within a joint to deteriorate. So doctors typically limit the number of cortisone shots into a joint. In general, you shouldn't get cortisone injections more often than every six weeks and usually not more than three or four times a year.