There are some simple techniques to correct common workout mistakes. You should look for cues, which come in forms such as lack or form or lack of engagement. Elastic bands and be used in order to help direct someone into proper form. This will give them resistance and help them to see/feel the proper motion. You should be further pushing them in the incorrect motion with resistance. Adding a heavy chain or a weight to the lower back during pushup is also an example. Resistance may be used with various exercises: e.g. lunges and weigh lifting. Sandbags are also a useful tool.