External Resistance and the Potential Adaptations


Louie Simmons popularized the use of bands and chains several decades ago. Coaches have been debating the effectiveness of each ever since. Some coaches swear by the use of bands and chains while others shrug it off as a waste of time. Luckily, I don’t go by what anyone thinks. I go by science, and my own experience using a method. Then I pass it on to all of you, so you don’t have to comb through all the literature that I spend countless hours reading over. Before I dive into the science, I want to answer a question I get a lot: “What is the difference between chains and bands?”


By Travis Mash


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“What is the difference between chains and bands?”


With chains, just like with normal weighted plates added to the bar, it’s the mass of the weight multiplied by the acceleration caused from gravity at a rate of 9.81m/s² that is responsible for the force to be overcome at the bottom of a squat or bench. Bands on the other hand add to the rate of acceleration with their elastic energy creating a faster eccentric velocity. Momentum is equal to mass multiplied by the velocity. If you understand the relationship between impulse and momentum, then you know that a greater force is now needed to create a change in momentum. If you read or watched my presentation on the different adaptations from the various muscular contractions, then you know that overloading the eccentric contraction is related to strengthening connective tissue, titin protein filaments, and all physiological components responsible for resisting stretch.  This increased eccentric velocity is also responsible for neural improvements within the stretch shortening cycle, and a greater prevalence for Type II muscle fiber hypertrophy (Arantes, V.H.F., da Silva, D.P., de Alvarenga, R.L. et al., 2020).


Chains act more like conventional weighted plates with gravity simply acting on the varying mass of the chains. You are still going to experience accommodating resistance that I am about to explain in detail. Not to mention, you will still experience a faster concentric contraction with any intensity when compared to using weighted plates only. Chains seem to be a bit more specific making the change to straight weight a little less awkward, so powerlifters might want to spend time with chains over bands before a competition. As you can see, both chains and bands have their purpose. Now that I have explained the difference between bands and chains, let’s take a closer look at the potential adaptations.

I have to admit that I was elated when Dr. Andy Galpin talked about bands and chains on the Huberman Lab Podcast. He went on to talk about the research that his group has been working on at Cal State Fullerton, and he spoke of the positive findings. What is the purpose behind bands and chains? I am so glad you asked. Let’s look at it.

Adaptations from Straight Weight on the Barbell

When an athlete uses straight weight on a barbell, the hip and knee joints are stressed the most in the bottom of a squat. In the bench press, the elbow and shoulder joints are stressed the most in the bottom of a bench press. Let me explain what actually happens when an athlete trains with a barbell. If you are lifting 100kg/220lb in the back squat, it’s gravity acting on the mass of the barbell that’s causing an external force to be overcome by the joints experiencing the stress. That force is 100kg x 9.81m/s² (force= mass x acceleration), which comes out to be 981N.  Yet, mechanical advantage changes throughout the lift due to changes in the moment arm, which is the perpendicular distance from an axis of rotation (example the hip) to the line of action of a force (imaginary line from the barbell straight down). In the back squat, the hips are overcoming an external flexion moment at the hip and knee, which is maximized at parallel due to the distance being maximized from the line of force perpendicular to the hip and knee. Here’s a diagram to make this easier:

Figure 1 Squat University Moment Arm

Most of the adaptations that athletes are after are caused by the joints being stressed to maximum. In the squat, the hips and knees overcome the most force in the bottom position. Therefore, the quads, hamstrings, glutes, and adductor magnus are stressed the most in the very bottom. I explained in the Range of Motion article that adaptations change wherever the joints are experiencing the most force to overcome. The position that the joints are in while experiencing the maximum amount of force changes the actual muscles that are recruited. For example, the adductor magnus is recruited the most for hip extension when the force is maximized in the bottom of a squat. The glutes become the primary muscle for hip extension experiencing max force at lockout. That means when an athlete squats with just a barbell and plates, the adductor magnus is the primary hip extensor. 

Dynamic Variable Resistance (Accommodating Resistance i.e. Bands & Chains)

What if I want my athletes stronger at the hip and knee with less of a joint angle? I can either do partial squats with a higher load, or I can add bands or chains. Now the knees and hips are experiencing the greatest amount of force to overcome at lockout. Boom, now glutes become the primary hip extensor. Bands and chains accommodate the change in mechanical advantage. As the line of action gets closer to the hip and knee, both the bands and chains are adding more and more resistance. 

Figure 2 Changes in Moment Arm via Fitness Pollenator

If you think about the angle of the hip, knee, and ankle joints during sprinting, change of direction, or most any other sporting event, you will see that you want to maximize the body’s ability to produce force near the end range of motion in back squats and pulls. Here’s an image to visualize the angle of the knee and hip joints during a sprint:

Figure 3 Hunter, Joseph, et al., 2005

As you can see, when the foot strikes the ground, the angle at the hips and knees is much greater. Full range of motions should be executed the majority of the time due to a wide range of adaptations, but adding bands and chains will accommodate this strength curve ensuring the body is capable of producing maximum force when the foot strikes the ground. Besides accommodating resistance, bands and chains produce a few other adaptations worth noting.

Chains and bands to an even greater degree, bands, allow athletes to move any given percentage of his or her 1RM at a higher velocity. This is due to the lighter load being experienced in the bottom of the squat allowing the athlete to build velocity and momentum to carry them through the end ROM where the bands or chains add maximum resistance. With bands, there’s another effect that not only increases the speed due to accommodating resistance explained above, but also the bands pulling on the barbell increases the speed of the eccentric contraction. Chains and the weighted plates added to the barbell create external force due to gravity acting on the mass of the object. Bands have very little mass for gravity to act upon. Instead, bands literally pull the athlete towards the ground with elasticity. This pulling effect increases the speed of the eccentric in the same way as if the coach was pulling on the barbell towards the floor. 

This increased eccentric velocity helps to increase the passive forces experienced at the various joints due to the stretch shortening cycle and the various elements responsible for resisting stretch (titin protein filaments, the collagen layers surrounding muscle fibers, and connective tissue). I explained the elements responsible for passive force in our topic regarding the various muscular contractions: Adaptations from Eccentric Contractions.

These adaptations lead to:

  • Improved Rate of Force Development
  • Improved ability to produce Power (Force x Velocity)
  • Improved Rate of Producing Peak Power

This group of adaptations are the reasons that I believe Olympic weightlifters, football players, and basketball players to name just a few should mainly squat and pull with bands, aka improving their ability to produce maximum force at a maximum rate of time. To be clear, it’s wise to focus on improving absolute strength for the first two years because Dr. Bryan Mann’s work shows that absolute strength improves all qualities of strength for the first couple of years. After the first two years, it’s imperative to focus on the qualities that are most important for the individual and that individual’s sport.


I hope this helps inform all of you regarding the possible adaptations experienced when using chains and especially bands. I can’t wait to read about the research from Dr. Galpin’s team at Cal State Fullerton. There are so many adaptations possible, but a coach has to know the stimulus that leads to the intended adaptation. However, you have to be able to track velocity, the load being overcome, and total time in the eccentric and concentric contractions to ensure the proper stimulus is being applied. Velocity-based training with GymAware RS and now the FLEX unit tracks all of these parameters that ensure the proper stimulus is being applied. GymAware also allows coaches to test the individual athletes to ensure the adaptations are taking place. With my athletes, I use GymAware RS and FLEX for many more reasons than just velocity. Rate of Force Development, time to peak force, bar path, eccentric velocity, and eccentric/concentric rate of contraction are just a few of the parameters that I can track and monitor my athletes with using the GymAware Cloud. The free app that comes with the GymAware FLEX units tracks a lot of these parameters:

  • Peak and Mean Concentric Velocity
  • Peak and Mean Concentric Power
  • Peak and Mean Eccentric Velocity
  • Concentric and Eccentric Time aka Duration
  • Bar Path 
  • Distance


If you understand biomechanics and physics just a little, then you know that you can just about figure out any other parameter with these stored calculations like rate of force development, eccentric force, and more. Of course the GymAware Cloud automatically calculates these and more. 

In Figure 4 below, you will see the importance of measuring the Depth Jump with GymAware for improvements in elasticity. The depth jump is an important test to determine if your programming is working. It’s no surprise that the most powerful athlete I have ever coached leads the way on all four parameters: peak power per kilogram of bodyweight, peak power, mean velocity, and height of course. We measure depth jump three times per week to track these changes in elasticity and to monitor neuromuscular readiness.


Figure 4 Depth Jump to measure Elasticity and Power

If you have any questions, email me at Travis@GymAware.com and I will try to help out as much as possible.


Watch the video below:



  1. Arantes, V.H.F., da Silva, D.P., de Alvarenga, R.L. et al. Skeletal muscle hypertrophy: molecular and applied aspects of exercise physiology. Ger J Exerc Sport Res 50, 195–207 (2020). https://doi.org/10.1007/s12662-020-00652-z
  2. Mann, Bryan & Ivey, Patrick & Sayers, Stephen. (2015). Velocity-Based Training in Football. Strength and Conditioning Journal. 37. 52-57. 10.1519/SSC.0000000000000177. 
  3. Weakley, Jonathon PhD1,2; Mann, Bryan PhD3; Banyard, Harry PhD4; McLaren, Shaun PhD2,5; Scott, Tannath PhD2,6; Garcia-Ramos, Amador PhD7,8. Velocity-Based Training: From Theory to Application. Strength and Conditioning Journal 43(2):p 31-49, April 2021. | DOI: 10.1519/SSC.0000000000000560


Coach Travis mash

Travis Mash

Being a World Champion in powerlifting, Travis competed at a world-class level in Olympic weightlifting and has coached professional Olympic weightlifters alongside Don McCauley and Glenn Pendlay at Team MDUSA. Now Travis coaches the most successful weightlifting team in the USA.