Excellent product! Clear labeling of resistance ranges on each BAND makes choice and combinations bands for each exercise quick , rational , and truly progressive resistance. The maximum stretch is three times the original length which is approximately 40 in for each loop-band. I used paper tape (like for painting), applied it to the floor in a hallway where I will be using the bands and marked off an extra 80 in at which the upper limit force labeled clearly on each band would be met. Also marking at 75 70 65 60 50 55 in etc allows me to know and record for my workout to poundages.
So that you may evaluate the value of my opinions: I am an MD with 46 years of experience in family practice and emergency medicine including sports medicine, with 58 years of active weightlifting and study of all aspects of strength training . I am now 73 years old, and the use of these latex bands has very substantially improved the quality of workouts that I can do at my age. I am actually building muscle mass and strength again. If you're into serious strength building these are superior to free weights for eccentric repetitions. I don't know if this is relevant but the acceleration force for eccentrics with free weights produces a 33-ft per second per second acceleration which must be counteracted by your muscle working. The acceleration with latex band is many times that. The latex bands also lend themselves to a great deal larger number of exercises which can be performed by regular concentric eccentric movement, or two arms to lift or stretch the band and then gradually release the assistance by the non-active arm or leg. It takes five to eight seconds for the body to ramp up to full eccentric intensity, so the release must be slow. However with a latex band resistance can be in a horizontal direction or any other direction you choose and movement of your body can further increase or decrease the actual force involved. The point of all this is you can
Use a force that is 100% of your ability to hold a static position. Then as the muscle tires it will elongate eccentrically.
It requires considerable concentration in central nervous system effort to control this process. Ideally you should be able to achieve the maximum force in each position for the full range of motion and do a deeper stretch at the end safely then would be possible with free weight.
This also allows you to design exercises that would be difficult even with a cable machine and far more efficient in strength development. Every portion of the range of motion that you can safely perform can be trained at optimum efficiency, for every muscle but right even including squats and shrugs (but for those I have had to use a 2"x12" x36" pine board with " U" bolts on either end to secure multiple highest strength latex bands passed through each " U" bolt with 500lb webbing around this center to attach to my lifting handles or harness.
The formula for determining force by displacement for each latex band is fairly simple, I got it using the AI on my phone.
Another major advantage of the latex bands over free weights is that they can much more easily be effectively used for exercises that may need to be in a very limited range of motion due to orthopedic problems arthritis etc and yet it is often possible to find a particular range of motion that's painless. Building strength in a range of motion that is painless will often produce very significant improvements in the symptoms of osteoarthritis, and even improvement in the range of motion.
I have three sets, and I would advise buying two sets at least in order to have predetermined bands or groups of bands set up for each of the exercises you would like to be able to do quickly. Get some 1-2" pulling webbing such as might be used for pulling cars and several high quality carabiners (500 lb.+)
And a set of figure eight lifting straps, if you plan on setting up a serious home gym using latex bands.
I have found these to be more versatile than free weights obviously much lighter and extremely small bulk, portable durable and many times the value of the same amount spent on free weights
