I had lost overall body strength due a painful hip injury that really hampered my mobility and limited my ability to exercise. I've recovered from surgery and I'm now catching up on recovering strength using this product.  I feel that the continual and steady resistance the bands provide through the entire exercise motion is more efficient in strengthening the targeted muscles than free weights. Steady resistance is much harder to maintain with free weights.  Even at light resistance, these bands provide that steady pressure that can be increased as the muscles strengthen, plus you can hold the pressure at any point during the motion simply by stopping for a count of 3 or 5, etc. This works great, for example, on bicep curls if you hold on the return motion when your elbows are at 90 degrees; makes you feel the burn! This system is allowing me to regain strength slowly, easily and steadily. The bands, the couplings, the handles, etc., are all well-designed and made of high quality materials.  Very well-satisfied with the quality of the product and the efficiency of the system. A big plus is that the set and the system travel very well!