Getting someone to switch from free weights to elastic resistance isn’t bringing them into the 21st century, it’s a lateral move at best. Also, lots of physics errors above. Read Moment Arm Exercise by Bill DeSimone for a better understanding of moment arms, torque, etc. in exercise.

The only problem I see with resistance bands for certain free weight exercises is that the place where the band will attach to the ground is static, whereas natural gravity pulls directly down at any given location a free weight exists in. For the squat, for example, near lock-out, you may have 200 lbs with an additional 50 lbs from resistance bands. The 200 lbs is pulled straight down by gravity, while depending on the location of the barbell the bands are connected to and the place on the ground where the bands are connected, the force acting upon the bar may not be directly down through the duration of the repetition. In fact, the force cannot be directly down for the entire rep, because the bar moves back and forth slightly as your body positions itself under it to push it upwards. The path of the bar will never be in a perfect vertical line. If the contrary were true, the use of stabilizing muscles would be null as we would be able to simply push up with no balance and not fall over. Earths gravity is not comparable to a smith machine. Therefore this particular use of resistance bands have an unnatural stimulation of the stabilizing muscles [or a lack of stimulation] which would in turn produce less functional strength than that which would be produced through the use of only free-weights.

Is there a way to counteract or defy this characteristic?