Particular Ranges of Motion come with Specific Adaptations
This week brings us to one of the most debated topics in strength and conditioning, “range of motion”. The movement that comes to mind for most is the squat (back and front). I’m old school with a preference in full range of motion especially for my athletes that happen to be Olympic weightlifters. However, this series isn’t about preferences, and no one is reading this to learn Coach Mash’s preference for squatting deep. Therefore, this week we are going to look at the science, and then all of you coaches can use the information to fit your specific population and the individuals within that population.
The common denominator that you are probably getting wise to if you have followed this series from the beginning is that the principle of specificity is the king of all principles. If you perform quarter squats, then you will get better at quarter squats. If you perform half squats, you will get better at half squats. The same goes for full depth squats. The key for strength coaches to understand is that even though you are getting better at each of the movements, the adaptations at each range of motion varies. By now, we have witnessed neural adaptations, neuromuscular junction adaptations, tendon and other connective tissue adaptations, and muscular adaptations. Of course at the cellular level, each of these groups of adaptations contain multiple properties that are each potential adaptations. Like most things, if you want to understand the real truth to all of this, the truth is in the detail.
Menu:
- Why full range of motion doesn’t strengthen all joint angles equally
- Adaptations from altered ranges of motion
– Changes in Optimum Muscle Length for Maximum Force Production
– Specific Hypertrophy Gains
– Neural Drive is Maximized at Joint Angles Experiencing Max Mechanical Loading - Parameters and Key Takeaways
- Possible transfer to sport
Typical Full Range of Motion
When performing any barbell or dumbbell exercise, an athlete will improve his or her ability to produce force more at some joint angles and less at others. This happens because the athlete isn’t required to produce the same amount of force throughout the entire range of motion. The total amount of external force to be overcome changes as the length from the joint to the line of force changes. We are simply referring to torque, which is a way of explaining rotational force production. Athletes produce force by the torque created at the various joints. Our muscles form junctions with the corresponding tendons that cross a joint connecting one bone or bones to another. The joint experiencing movement in a particular exercise is expressing internal torque to counter any external resistance. The external torque is equal to the horizontal distance of the resistance force perpendicular to the joint or axis of rotation.
To explain this in simpler terms: when an athlete performs a back squat, the external line of force to be overcome is gravity acting on the barbell in a straight line from the barbell down to the ground. The main joints that are involved in overcoming the external force are the hip, knee, and the intervertebral joints. In the bottom of a squat, the knee, the hip, and each intervertebral joint are as far as possible from the line of force created by the barbell. That’s the point where those joints are required to overcome the most force. As the athlete stands up, their knees, hips, and intervertebral joints move closer to the line of action making the lift easier and easier until they are standing vertical and experiencing the least amount of external resistance.
When using a barbell or dumbbell, there are two factors related to the external resistance:
1. The amount of weight on the barbell
2. The distance of the lever from the axis of rotation(joint) to the line of action.
A full range of motion will normally yield the greatest amount of hypertrophy, but at the end of the day the body becomes more efficient at creating maximum force at longer muscle lengths. If you remember the principle of specificity, this isn’t optimal for athletes that are trying to create maximal force at shorter muscle lengths like during a sprint, vertical leap, or change of direction. Luckily there is more than one way to coach an athlete.
If you want to create athletes capable of maximum force during shortened muscle lengths, you train them with maximum mechanical loading during shortened muscle lengths. For all of my meatheads out there, I am talking about performing partials. Once again, let’s look at the back squat. The reason that powerlifters perform those obnoxiously high squats is because they can lift more weight if they don’t go as low. Luckily for those athletes out there that love squatting big weights with a smaller range of motion, there’s a time and place for those quarter or half squats. If an athlete increases the load to a circa-maximal range that accommodates a specific range of motion, the athlete will improve their ability to produce force at that particular range of motion. The athlete is training their ability to produce maximal force at shorter muscle lengths.
Adaptations Leading to Joint ROM Force Capabilities
1. Changes in the Optimum Muscle Length for Maximum Force Production- Chris Beardsley explains this so well in his book Strength is Specific. Sarcomeres are the smallest contractile units found within a muscle. If you have been keeping up with this series, you have heard me talk about the actin and myosin cross-bridges. The more overlap between actin and myosin leads to maximum amounts of force. Full range of motion squats, presses, or any movement really creates an adaptation of adding more sarcomeres in series. Researchers have found that hypertrophy from full range of motion exercises occurs at the ends of a muscle, which is consistent with sarcomeres being added in series like an extra link in a chain. On the contrary, shortened range of motion exercises can cause sarcomeres to be lost resulting in less overall sarcomeres or more sarcomeres in parallel (side by side). Result:
- Full range of motion exercises causing more sarcomeres in series results in each sarcomere length to be shorter at any given muscle fiber length, since that length doesn’t change. This leads to more myosin-actin crossbridge at longer muscle lengths resulting in more force at longer lengths.
- Partial range of motion exercises resulting in the loss of sarcomeres in series results in the length of each sarcomere being longer at any given muscle length because the length of the muscle fiber is the same. This maximizes the actin-myosin cross bridges at shorter muscle lengths optimizing force production at those short ranges of motion while creating a lesser ability to create force at longer lengths.
- Causes for Maximal Torque (rotational force): there are two causes for a muscle to experience maximum torque, and those are moment arm and load. Moment arm is simply the perpendicular distance from the axis of rotation aka the joint and the line of action of gravity acting on the load aka barbell. The only way to account for a shorter moment arm formed during a partial range of motion exercises is with an increased load. Therefore, if you want to strengthen a joint while the muscle is shortened, you have to overload the weight being used.
2. Specific Hypertrophy Gains – full range of motion exercises create specific hypertrophy gains normally seen at the ends of the muscles. This regional hypertrophy gain isn’t fully understood, but Chris Beardsley seems to think that lengthened hypertrophy is the added sarcomeres because it makes sense that the added chains would be towards the end ranges of motion. To be clear, it appears that overall hypertrophy is maximized with a full range of motion, but training at shortened muscle lengths also stimulates hypertrophy just specific to that length.
3. Neural Drive is Maximized at Joint Angles Experiencing Max Mechanical Loading– by now we’ve gone over motor unit recruitment and rate of coding adaptations. A motor unit is an alpha motor neuron and all of the muscle fibers that it innervates. Rate coding pertains to the speed of that signal from the brain telling those muscle fibers to activate. Maximum motor unit recruitment and the increases in rate coding are directly related to the joint angle experiencing maximum mechanical loading
Parameters and Key Takeaways
For the first couple of years, the goal is a full range of motion until a base level of relative strength is reached. Most studies recommend reaching a maximum back squat of 1.7 to 2.2 times an athlete’s body weight. Plus, the best way to maximize the range of motion of an athlete is with exercises that require maximum range of motion. As Dr. Andy Galpin says, “the best way for an athlete to maximize flexibility is to never lose it. After a 2-times bodyweight squat is achieved, that’s a great time to test the athlete’s force-velocity profile, along with other specific athletic characteristics, and specify training based on the athlete’s specific sport.
I also recommend using exercises that require an athlete to move through an entire range of motion in the different vectors of play: vertical, horizontal, lateral, and rotational. If you’re squatting, I recommend using front squats, back squats, unilateral squats, and side to side lateral squats. Lastly, I recommend targeting all ranges of motion quarter, half, and full ranges of motion. The goal is to optimize strength development at all joint angles, prevent overuse injuries, and develop total athleticism.
For partial squats, if you are not a strength athlete, I recommend using a belt squat for partial and half squats to avoid excess axial loading. If you are a football player or rugby player, you could make a case for strengthening the torso and keeping the barbell in for at least some partials or half squats. For speed specific, the belt squat is the way to go, but we are going to get into speed and athletic improvements a bit more now.
Possible Transfer to Sport and Using Velocity for Maximum Specificity
For all of you ass to grass or nothing strength coaches out there (P.S. I used to be one of you), I am issuing a trigger warning right now. Rhea, M., et al., 2016 performed a study on 28 college athletes who participated in a 16-week study that looked at the relationship between quarter squats, half squats, and full range of motion squats as they compared to vertical leap, 40-yard dash times, and strength. Believe it or not, the quarter squats group produced the highest vertical jump and greatest improvements in 40-yard dash times followed by the half squats group with the full squats group coming in last. Each group maximized force production in their specific range of motion.
Why? For one thing, the joint angle strengthened during quarter squats is more specific to sprints and vertical leaps. Like I have already explained, the adaptations that take place during heavy partial range of motion exercises allow the joints to express maximum force at that specific angle. The adaptations that create the most specific adaptations to speed are rate coding and maximum motor unit recruitment and synchronization. That means the body gets more efficient at recruiting the maximum number of motor units, and the speed of that recruitment increases. Lastly, most people can quarter squat 30-45% more than they can squat below parallel. That means the joint is only experiencing around 70% of its max lifting capability when performing full range of motion movements.
Uses for Velocity
As usual, I like to use my GymAware RS or my GymAware FLEX units to emphasize specific adaptations. For example, I suggest looking at Time to Peak Force while tracking joint angle specific gains in strength. If an athlete is gaining greater capabilities to produce force, but those capabilities are slow in nature, then the adaptation is nearly as valuable for a sprinter or wide receiver. Plus, I would use a velocity cut off to protect the athlete like 0.35-0.4m/s mean velocity at any given range of motion. Lastly, Dip (m) allows the athlete or coach to analyze the eccentric distance to ensure specific comparisons are being made.
One more point, once an athlete has sufficiently developed strength at a particular joint angle, once again it’s time to get more specific with the quality of strength that you are continuing to improve. Go back and read or listen to the “Repetition Velocity” episode, and next episode we will discuss different types of external resistance. Bands might very well improve this adaptation in regards to the rate of force development. More on that next time, but you can all look forward to the final episode in this series where I will unveil a possible periodized program using all of these stimuli to acquire maximal adaptations.
I want to leave you all with a thought to my fellow weightlifting coaches. You could easily use this range of motion stimulus to create adaptations leading to better jerks. I know that I have already been doing this with partial squats and partial squats with bands. This has worked like magic. Thanks for tuning in, and as always please email me at Travis@GymAware.com with any questions or suggestions.
References:
- Rhea MR et al. Joint-Angle Specific Strength Adaptations Influence Improvements in Power in Highly Trained Athletes. Human Movement. 2016;17(1):43-49.
- Bloomquist, K., Langberg, H., Karlsen, S., Madsgaard, S., Boesen, S., & Raastad, T. (2013). “Effect of range of motion in heavy load squatting on muscle and tendon adaptations,” European Journal of Applied Physiology, 113(8), 2133-42.
- Pallarés JG, Hernández-Belmonte A, Martínez-Cava A, Vetrovsky T, Steffl M, Courel-Ibáñez J. Effects of range of motion on resistance training adaptations: A systematic review and meta-analysis. Scand J Med Sci Sports. 2021 Oct;31(10):1866-1881. doi: 10.1111/sms.14006. Epub 2021 Jul 5. PMID: 34170576.
- Wolf, M., Androulakis, Korakakis, P., Fisher, J.P., Schoenfeld, B.J., & Steele, J.,(2022). Partial vs full range of motion resistance training: A systematic review and meta analysis. DOI: https://doi.org/10.51224/SRXIV.198
- Beardsley, Chris. Strength is Specific: The key to optimal strength training for sports (p. 149). Strength and Conditioning Research Limited. Kindle Edition.
- Tuura, Jake. “Quarter Squats Are Your Secret Weapon to Sprinting Faster and Jumping Higher”, Stack.com, (2017) 2-27-2017
- Baar K. Minimizing Injury and Maximizing Return to Play: Lessons from Engineered Ligaments. Sports Med. 2017 Mar;47(Suppl 1):5-11. doi: 10.1007/s40279-017-0719-x. PMID: 28332110; PMCID: PMC5371618.
- https://www.mysportscience.com/post/gelatin-and-injury
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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.
