Some years ago, powerlifters began attaching either elastic bands or chains to barbells, to alter the type of resistance that they were working against during squats, bench presses, or deadlifts.
As some of these powerlifters became very successful in their sport, the practice of using bands and chains spread to strength coaches, who started using them to train athletes in other sports.
But was it really appropriate for these strength coaches to adopt this type of training? Or is it only applicable for powerlifting, and not for training other athletes to help them jump, throw, and sprint?
To help answer that question, we need to go right back to the beginning, and understand why we might want to add bands and chains to a barbell in the first place.
Why did powerlifters adopt bands and chains?
It seems likely that powerlifters started using bands and chains because they realized it allowed them to alter what they termed the “strength curve” of an exercise.
In powerlifting, the “strength curve” describes the gap between the force you are *able* to exert and the force that you *need* to exert to move the barbell, across the whole exercise range of motion.
When we squat with just a barbell, we need to exert a force that both overcomes the effect of gravity throughout the lift. In the bottom position, we also need to exert a force that accelerates the barbell from a stationary start. This is called overcoming inertia. This makes the force that we need to produce greater in the bottom position than at other points in the exercise range of motion.
Additionally, when we squat, the barbell has *its* best leverage on us at the bottom of the squat, because this is where our hip and knee joints are furthest from the barbell. As we stand up vertically, our hip and knee joints move horizontally towards a vertical line drawn down from the barbell, and so the leverage of the barbell reduces. This also makes the squat much harder in the bottom position than in the rest of the exercise range of motion.
The need to overcome inertia and the changing leverage of the barbell each contribute to make the “strength curve” of the barbell back squat very steep, such that the bottom of the exercise can be extraordinarily difficult, while the rest is comparatively easy.
Bands, reverse bands, and chains all reduce the weight of the barbell at the bottom of the squat, and add resistance higher up in the lift. This “flattens” the strength curve and makes performing the squat a different experience, one that is not as grueling in the bottom position, but remains difficult throughout.
This is why this bands and chains are sometimes called “accommodating resistance,” because they are used to match the resistance provided by the barbell with the force produced by the muscles.
Why did powerlifters want to alter the “strength curve”?
Some people think that powerlifters originally began altering the “strength curve” of the lifts so they could use unequipped lifts (without powerlifting suits) to train the sticking points of equipped lifts (with powerlifting suits).
Others have suggested that it was an attempt to provide a different stimulus to the muscle, and produce a transferable adaptation that would not otherwise occur.
Whatever the original reason, we now know that training with bands or chains *does* cause strength gains in two different ways when compared to traditional weights.
One way occurs because of the faster speed and longer acceleration phase that occurs when using bands or chains with the same percentage of one repetition-maximum (1RM). This leads to greater gains in high-velocity strength than are achieved with conventional weights.
The other way happens because of the greater resistance that is achieved later in the exercise range of motion, when the agonist (prime mover) muscles are shorter. This leads to greater gains in strength at short muscle lengths than are achieved with conventional weights.
Why do bands and chains involve faster speeds?
When we start the upward phase in the squat, the load determines how fast we move, because of the force-velocity relationship.
If we are lifting a very heavy weight, we accelerate gradually to a slow speed, ride through the middle as the “strength curve” eases off, and then decelerate towards the end, as we reach lockout.
In contrast, when we lift light weights, we accelerate quickly to a high speed, cruise through the middle of the lift, and decelerate towards the end, as we reach lockout. If we lift a very light weight, we might even begin decelerating in the middle of the lift, to avoid leaving the ground.
So what do bands and chains do?
Well, if we remove some weight from the barbell so that we can add bands or chains, then this reduces the load at the start of the lift. This has a doubly effective impact, because the reduced load requires less force to overcome the force of gravity, and also less force to accelerate (inertia).
Consequently, we accelerate more quickly and reach a faster speed in the middle of the lift, and we also accelerate for longer, because the bands or chains keep adding resistance as we progress through the lift (this happens even when we match the same percentage of 1RM with both types of resistance).
Moving faster, and accelerating for a longer period of time seem cause greater gains in high velocity strength, and this could happen through any of adaptations, such as increased early phase neural drive, type IIX fiber retention, faster muscle fiber contraction velocity, velocity-specific coordination, or reduced antagonist (opposing) muscle activation.
How does greater resistance later in the exercise range of motion cause different adaptations?
When we perform the upward phase in the squat with only a barbell, our muscles are challenged most in the bottom position, where they are stretched. They are not subject to anywhere near as much mechanical loading during the remainder of the lift.
This loading in a stretched position causes specific adaptations, which only occur when the muscles are stretched forcefully by heavy loads.
Among these specific adaptations is a shift in the joint angle at which we can produce peak force. This likely occurs by an alteration to the length-tension relationship, which happens when we add contractile units (sarcomeres) at the ends of individual muscle fibers to make them longer.
In contrast, when we add bands and chains, our muscles are not as strongly challenged when they are stretched, but they are subjected to more mechanical loading at other, shorter lengths.
This loading at short muscle lengths also causes specific adaptations, of which the most important is an increase in the size of the signal from the central nervous system at that specific muscle length, which makes us stronger in that particular range of motion.
Should strength coaches use bands and chains?
Bands and chains can absolutely be a very effective and valuable training tool, so long as you understand what you are *actually* doing when you put them on a barbell.
If you want to improve strength at high velocities, they do have the advantage over free weights. And this may be useful for team sports athletes, who need to sprint, throw, jump, and change direction quickly.
Similarly, if you want to improve strength at shorter muscle lengths (more extended joint angles), they also have an advantage over free weights, and this may be quite applicable to some athletic movements, including vertical jumping. This is also *probably* why bands and chains work as well as they do for equipped powerlifting.
In contrast, using a barbell without bands and chains will likely always *eventually* increase strength more at long muscle lengths, which ironically makes them a much better bet for unequipped powerlifting.
Naturally, there will always be some powerlifters who disagree with this, and claim that bands and chains is very effective for improving unequipped powerlifting. I don’t doubt for a moment that this happens, and I think every competitor would likely benefit from trying it for at least one training cycle. But I think it occurs for the same reason that some (but not all) lifters benefit from the dynamic effort method. They are the lifters who had not previously achieved any of the benefits of lifting quickly, and bands and chains produce similar effects, which then transfer quite quickly.
What is the takeaway?
Adding bands and chains to a barbell to alter the “strength curve” can be a useful tool for training athletes, because it produces greater gains in high-velocity strength than normal free weights, and also leads to a larger strength increase at more extended joint angles (shorter muscle lengths).
Even so, there are other cases when just using the barbell is better, such as when strength at more flexed joint angles (longer muscle lengths) is needed, as in unequipped powerlifting.