Battle ropes RSS
Use bent legs to work your legs and core to hold your position, don't lock out your back and put pressure on the lower back.
Why SAP Cords are better than Battle Ropes. Battle ropes have one load, can only be used as battle ropes are heavy to carry. Customer feedback on SAP stretch cords is that they are great because they can be used over a wide range of loads, can also be used for over-speed training and (phew) are light weight to carry about. Also Great news stretch cords can be fun as you can have two people using them - one at each end.