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For a quick re-cap, the conversation included a refresher on adductor anatomy and how that creates torsion and compression through the lower half, and how athletes can tap into that behavior.

We go over an example in a free kick in soccer, and how the torsion from that adductor group influences the curve on a free kick.

Lastly we covered different activities that are great early introductory positions for individuals that struggle to get expansion through the upper thorax, as well as how to progress them from these early interventions to weight room activities.

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Not as a means to an end but more as a confirmation that you are doing something right in terms of the process that you are putting your clients through:)

Let me know if y…

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There’s useful variability that allows you to adapt to a changing environment…

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If you’re a free subscriber, these Q and As are a valuable way to ask some of your more burning questions and improve your understanding of how to apply these concepts to your own cases!

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This is a case study that highlights the shortcomings of two “truths“ I was taught in PT school, and how updating my understanding of these concepts helped me create a more useful treatment plan.

When…

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Hope this helps …

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This week we breakdown the Campo Deadlift and possible applications.

It’s a fun episode where we get to bounce some ideas off each other and show some video demos.

Look for more member o…

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Here’s the link:

https://us02web.zoom.us/j/84207772351?pwd=QCyfMeZV…

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We’re certainly known for having a global perspective a…

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I thought this case study was worth sharing since I know many people struggle with similar issues that my client had. Not saying these things (braces, orthotics etc.) are never useful b…

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The case studies are useful. They show the process. They show what we’re looking at, what we change, what we think matters, what m…

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• Regaining and re-training dorsiflexion to improve plantar flexion.

• Learned strategies vs strategies demonstrated due to structure and constraints.

• Creating IR through the mid-foot vs hind-foot, fighting through the ER twist of the achilles

• Twists through tendons and considerations for re-capturing movement.

We hope you enjoy and take away something useful!

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Programming for Performance: Throwers and Jumpers

For overhead athletes we’ll be focusing on the connective tissue of the shoulder, primarily the larger more superficial muscles (Lat, delt, pec), and for a field/court athlete we’ll look at an Achilles. Though these are different body parts, the over arching principles for eliciting adaptations still apply. Timelines for healing and recovery from training are still similar as well.
When periodizing for seasonal athletes we must divide between off-season and in-season for mainly two reasons. First, with these structural adaptions to tissue, time is the biggest factor that we need to appreciate, rather than programming in microcycles with only days in mind, we need to stretch our timelines out to weeks and months. Second, and in my opinion more underappreciated, is that adaptations don’t just happen in the weightroom, the sport itself is a massive driver of structural and neural adaptions. We need to be aware of the type of stimulus and resulting adaption that the sport will provide and make sure to try to maintain these adaptions rather than continuing to feed into what the sport is already providing.

In-Season Considerations:

For In-season athletes, the actions they’re demonstrating will be a VERY HIGH VOLUME of sprinting, jumping, and throwing. This should be thought of as if they’re performing an extremely aggressive plyometric program in the weightroom. They’re exposing their connective tissues to high strain, short duration loading, as we’ve covered in pt. 2, this is a great recipe for building stiffness by enhancing the elastic modulus of the tendon and making the stress-strain curve steeper. Also, during sport there is going to be a considerable amount of loading in linear region of the curve (3-6%) strain where we’re potentially creating micro-damage to these tissues, damage that these athletes need to recover from between bouts of activity. This timeline is usually in the 2-5 day range. Another factor that we haven’t discussed yet is the hydration status of the tendon. The fluid dynamics of tendons is a loaded topic, one that is vastly underappreciated and under researched. We’re aware of how useful fluid dynamics are in recovery as well as the fact that water moves through a tendon before and after exercise, but what is mostly unknown is how it moves through a tendon during exercise, with fluid dynamics likely influencing the demonstrated behaviors of a tendon that we’ve been discussing. During High Volume, High Strain activities (sports) it is very common for the tendon to be de-hydrate for 2-3 days following that activity (eerily like the timeline for replenishing collagen…).

With In-season athletes already getting very high dosages of loading that would induce tendon stiffness, they’re also in situations that have tight windows of recovery, because between games and practices the likelihood that these tissues are ever fully recovered is low. With these parameters laid out, we need to be very particular and conservative about the volume of exercise we’re prescribing that would be inducing stiffness in-season, whether it’s high intensity plyometrics, or overcoming isometric activity. Not saying to never do them, as they can be beneficial from a neural activation and coordination standpoint, but consistent dosages or a single weekly bout in high dosages should be prescribed with caution, and certainly not for the entirety of a competitive season.

Instead, in-season exercise prescription for tendons should likely focus on activities that are lower in strain that target more of the toe region of loading for the tendon. The main reasons being that this loading is much easier to recover from, and can potentially be beneficial to recovery since it can enable re-hydration of the tendon. These adaptations that revolve around improving tendon elongation can also serve to balance out the stiffness adaptations taking place within the sport.

In-season exercise prescription for connective tissue should focus around a few goals, activities that would improve tendon hydration, loading that would reduce the amount of strain placed upon a tendon, and activities that would enable tendon elongation to offset the stiffness adaptations from sport. The main thing that will enable the re-hydration of the tendon is REST, just don’t load it, ideally for 48 hours, but sometimes competitive and practice schedules prevent this. The next best thing is going to be strength training with low to moderate loads, which should make sense from our prior conversations as higher strains held for longer periods is more likely to cause a de-hydration of the tissue. Last would be higher strain activities, but with the strain only lasting for brief periods, and with these activities performed at lower volumes, which essentially just describes plyometric training. These activities also already outline what a micro-cycle would look like.

In-Season Training:

So let’s walk through an in-season scenario, a starting pitcher with 5 days in between outings, or a basketball player (could be soccer, or lacrosse, or football) with 3-5 days in between games depending on the competitive schedule.

With 5 days in between competition that effectively gives the S&C/medical professionals 3 days to prepare the athlete for the next outing. If Monday was their last game, Tuesday, Wednesday, and Thursday can be used to prepare for another one on Friday.

The main goals on Monday and Tuesday are to recover and reduce the strain placed on the connective. This would mean that activities that would help to reduce any concentric orientation of musculature from the prior outing should be the main thing employed within this window. This could look like soft tissue work, cupping, dry needling, foam rolling, respiratory activities, body weight exercises, whatever is in your toolbox to reduce muscle activity should be employed for the first 24-48 hours.

Once Wednesday rolls around lower to moderate intensity loads can start to be re-introduced to continue to enable re-hydration. This would also be a good window to utilize Tempo training or BFR training, these modalities employ lower strains and intensities on the tissue but can still elicit the necessary adaptations. This would also be a good day to use moderate loaded eccentrics to continue to encourage improved connective tissue elongation. Load could be undulated from low intensity to moderate intensity week by week in order to continue to facilitate other adaptations such as muscle hypertrophy and motor unit recruitment.

Thursday would be a good day to initiate some ballistic and plyometric activities. Though the emphasis can change on execution, specifically the amplitude of the plyometric exercise. For the upper half if we consider something like a plyometric drop catch for the rotator cuff or larger IR muscles, rather than having a smaller stiffer amplitude, enable maximal elongation with larger amplitudes, helping to continue to enhance the elongation of the tissue. This day can also serve as a neural prep day to enhance central and peripheral nervous system activity.

Friday, day of competition, more specific plyometric based activities can be employed at lower volumes, with the goal of essentially “tuning” the nervous system and the muscle connective tissue complexes to maximally enhance power output. This would be one of the few times in-season that overcoming isometrics (traditional stiffness training) could be appropriate for the athlete depending on the situation.

If there is an even more curtailed schedule of only 3 or 4 days of competition then this is another scenario where undulating periodization can be employed week to week. Continue to prioritize rest and recovery each week, along with switching between prioritizing moderate strength training one week and plyometric activities the next week. Preparatory activities prior to competition can continue to utilize higher intensity plyometric exercises.

Rehab:

In a rehabilitation scenario of connective tissue, whether that is post-surgical repair, or with a tendinopathic tissue in both scenarios we are dealing with tissue that will have a yield point that has moved DOWN and LEFT, indicating that it has reduced the amount of strain energy it can absorb, it takes less force for the tissue to reach a strain percentage that leads to damage, it is simply not as tough.

So, the overarching goal would be to make it so that it is tougher once again, simply meaning that we must train both stiffness and elongation to move that yield point UP and RIGHT once again. However, I feel that the timeline for either adaptation needs to be considered. Blocked periodization (prioritizing one adaptation prior to another) may be a better strategy in order to maximize the enhancement of toughness. As discussed in pt. 2, when training to enhance tendon elongation there is an increase in the size of the toe region of the stress strain curve of the tissue, that’s what moves the yield point to the right. When also training elongation, we typically don’t see a reduction of stiffness or a flattening of the slope of the linear region. However, when training stiffness, a shortening of this toe region can occur, this would steepen the slope of the linear region, but reduce the overall surface area under the curve, thus making the tissue slightly less tough.

It’s likely more beneficial to bias more of the stiffness training to earlier on with the rehab plan. Utilizing activities that are meant to enhance CSA, and increase the slope of the elastic modulus. These would include your overcoming isometrics, heavier eccentrics, and progressions to smaller amplitude and stiffer plyometric activities. Once adequate levels of stiffness have occurred switching towards exercise that train the tendon through lower strain percentages and greater amplitudes would then take the stiffness adaptations (steeper slope) and then layer on the elongation adaptations (longer toe region) and create your tougher tendon.

The rehab timeline matters based on the timeline for adaptions to occur, with shorter rehab times of 2-3 months then both qualities would likely need to be trained at once. Just changing which one has priority over the other based on the week. The first 4-6 weeks, the stiffness qualities will likely need to take precedent, at the half way point each quality will have equal dosage, and then through the last 4-6 weeks more of the elongation qualities will be trained. In post-surgical scenarios with timelines in the 6-12 month range, more time can be dedicated to these qualities individually.

Through this series the goal was to help create a framework for taking the principles that govern tissue behavior and translate that into application. We can utilize the stress-strain curve as a visual representation of the behaviors, as well as objectively defining the necessary adaptions needed to enhance the physiology. Using this to not only better understand the behavior of this tissue, but also to serve as principles for understanding the needs of each individual athlete and how to best approach their training.

- Campo

It’s not enough to simp…

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Not from the usual “just load it heavy and hope the tissue adapts” angle.

Before we get into the isometric/tendon heavy work, we have to ask a …

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For this month we’ll be covering a case of neglected rehab for an Achilles mid-substance tear. This particular client had a very hands off recovery process from a non-surgical achilles repair. The te…

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Here’s the link for part 1 if you need to catch up missed it. (Part 1)

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In the S&C and rehab world there is another curve that get’s a lot of attention. That is the Force-Velocity curve. Just like we use this curve as a framework for how we think about exercise selection for force and power training. The Stress-Strain curve can serve as a framework to think about how we can modify tendon behavior. On the bottom part of the curve we have strain, this is how much a tendon stretches. On the left of the curve is stress, how much load or force is required to stretch the tendon.
Just like with the force velocity curve, we can train either end or any where in between (thus “surfing” the curve). I can train at lighter loads for faster velocities, or I can train at heavier loads and slower velocities. With the goal of increasing the surface area under the force velocity curve, which is our objective indicator of increased power output. When training the stress-strain curve, I can either attempt to increase the amount of strain a tendon can demonstrate, or I can increase the amount of stress a tendon can tolerate. When doing this I increase the amount of surface area under the curve, this is the measure of strain energy, which is our measure of toughness. When this happens, we move the yield point (our north star) UP and RIGHT.

To increase toughness and move the yield point UP and RIGHT we must find the balance between our two variables, stress and strain. So, what the common ways we can use exercise to enhance both of them?

Building Stress:

The shape as well as the material nature of a tendon heavily dictates its behavior. If we remember back to the equation for stiffness:

Stiffness = Cross Sectional Area ((CSA) x Elastic Modulus)/Tendon Length

From this equation we can see that both CSA and the elastic modulus (slope of the curve) positively influence stiffness. We can divide these two adaptations into structural adaptions and behavioral adaptions respectively. In regards to structure, the wider a tendon is, the stiffer it is, the more force is required to deform the tissue. With modifying behavior we’ll often see a steeper slope of the stress-strain curve.

So we’ve isolated tendon CSA and elastic modulus as our factors for stiffness. Now like any adaptation we’re trying to improve with training, there are three main questions. What training stimulus is necessary to increase this trait? How much of a change is realistic? How long do we have to train before we see any meaningful change?

Let’s answer the training stimulus question first, and we can go back to the stress-strain and use this as a rule of thumb to help with loading principles for our exercise selection. We can divide the curve into 3 major regions, these regions largely differ based on tissue behavior, this behavior changes as the strain increases.

Toe Region: Justly named for it’s “J” shaped appearance at the bottom of the curve, this region typically occurs from 0% to 2-3% strain of total tendon length. (We’ll revisit this region in more detail when talking about enhancing tendon elongation as an adaptation).

Linear Region: Having a linear slope, this region will occur from 2-3% to 6% strain of total tendon length. However, keep in mind that micro-damage starts to occur in the 4-5% range of strain.

Yield/Fracture Region: This is where that slope starts to plateau significantly, the reason for this is macro-damage starts to occur in this region, instead of strain and tissue deformation we get tissue damage. This occurs 6% - 10% of strain.

With these regions in mind, and the strain percentage required to access each region the stimulus and the loading parameters start to become more straight forward. When trying to train stiffness, the purpose of stiffness is to prevent strain from occurring. Most protocols to improve stiffness need to push the amount of strain being placed on the tendon to the 4-5% range. Take this excerpt from Arampatzis et al. who looked at tendon changes at both high and low force loading.

“…a plantar flexion moment at 90% of the MVC should induce

between 4.5 and 5.0% strain.”

So what’s needed is a sustained high intensity muscular contraction in order to pull on the tendon hard enough to strain it up into the middle to end range of the Linear Region of the curve. What also matters is time duration of loading. Tendon behavior is rate dependent, meaning it’s behavior changes depending on if it’s loaded faster or slower. Studies that look at protocols with high force and longer duration (>3s) loads are usually the ones that consistently show a change in both CSA and young’s modulus. Where as studies looking at plyometric loading may show increases in stiffness, but CSA won’t change as consistently. In terms of stimulus, if I’m looking to increase CSA I must have high strain of >4% and this load also has to be sustained for >3 seconds. If I want to just increase stiffness via the elastic modulus (steeper slope) then I just need the higher strain. Hence the prevalence in popularity of overcoming isometrics for “tendon health”, but keep in mind stiffer doesn’t always mean better. It just means stiffer.

Now let’s look at the potential amount of increase in stiffness. When it comes to increasing stiffness you can typically anticipate an increase of 20-25%, but that increase in stiffness isn’t split 50-50 between CSA and young’s modulus. Seynnes et al. found that the patellar tendon stiffness increased by 24% following a high load protocol, the modulus increased by 20%, but the CSA increased by 5-6%. This is a typical disparity, the modulus will increase anywhere from 15-20%, but CSA gains will range from 0 – 9%. It’s well accepted that changes in stiffness will largely be driven by changes to the modulus, and changes to the CSA aren’t as drastic and sometimes never occur in studies.

When it comes to timelines, like most structural changes they take time, 8-12 weeks of training should be given to see significant changes with stiffness, especially CSA.

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Elongating Strain:

The popular topic for training tendons mostly revolves around training stiffness. A Meta-Analysis done by Fu et al. in March of 2026 showed that 37 studies looked at protocols to increase stiffness, 29 studies looked at increasing CSA, but only 11 studies looked at increasing tendon elongation. Building bigger thicker and stiffer tendons to help prevent strain is useful, but as discussed in the first article, strain and particularly increasing strain energy is a necessary and useful quality, that’s the defining feature of a tougher tendon. This is helpful only for performance but mitigating the degradation of the tissue. Enabling more elongation to occur within in a tendon isn’t specifically sought after within training and research as much, but it is possible.

There are a few ways the amount of strain can be increased. The first is by increasing the resting length of a tendon. Strain is calculated as a percentage (as we saw with the different regions of the curve). It is a percentage based off the overall length of a tendon. 3% of a 25 cm long tendon would be more then 3% of a 20 cm long tendon. However, outside of the normal growth and development of puberty, resting length of a tendon has not been shown to change in a meaningful way, at least not like the changes we see with CSA.

The main way we see changes in strain is changes in dynamic tendon elongation, this change is based on tendon behavior. Just like with stiffness we can use the stress-strain curve as a guide to help us with understanding what type of loading is necessary to help with increasing tendon elongation. With stiffness, loading within the linear region (3-6% strain) was necessary. For encouraging elongation we’re looking for loading within the toe region (1-3% strain). The same study from Arampatzis et al. that look at high and low force loading highlights the estimated strain based on the muscle activity within their study.

“…we predicted that a plantar flexion

moment at 55% of the achieved maximum moment during a

maximum voluntary contraction (MVC) should induce a

tendon–aponeurosis strain between 2.5 and 3.0%”

So training at submaximal strain percentages, primarily within the toe region is important. Does the type of loading matter? In the same meta-analysis done by Fu et al, they showed both eccentric and plyometric training is useful in increasing elongation. An eccentric study done by Foure et al. utilized a classic Alfredson eccentric loading protocol, but what they also added to the protocol was doing eccentric calf raises off of boxes of differing heights, insuring that the tendon was being elongated more and more while under strain. A plyometric study done by Kubo et al. had participants doing calf and achilles isolated plyo’s off a sledge apparatus, this enabled participants to go through greater excursions of tendon length while under strain forces. Putting these pieces together, loading within the toe region and the loading occurring through greater ranges of motion seem to be crucial for enabling increased elongation. The timelines for these are similar to the training for stiffness, spanning across 14 and 12 weeks respectively.

The Kubo et al. most interesting, because they demonstrated a few different variations that are noteworthy. First, they are one of the few studies that looked at tendon behavior before and after training at different speeds, or rates of loading. Testing participants with both ramp and ballistic loading. Second, they primarily saw changes to tendon elongation within the toe region, meaning that it was toe region itself that showed more elongation, not the linear region, but stiffness stayed relatively unchanged. This is most ideal because we wouldn’t necessarily want increased elongation in the linear region, because strain percentage is the objective marker of tendon degradation from loading (~5% for micro-damage and >6% for macro-damage). So enabling more elongation within the toe region would allow for more energy absorption at strain percentages that occur most often in sport and life, but doesn’t make it easier for the tendon to be strained to damage inducing levels.

In the above video, I show examples of some of the types of exercise used for each adaptation. The first clip is a static overcoming isometric meant to induce a high motor unit recruitment of the muscle, leading to increased stiffness. The second is a long duration eccentric into deeper ranges of dorsiflexion leading to increased elongation. Third, is a band assisted plyo into deeper ranges of dorsiflexion, leading to more elongation. Lastly, a typical pogo hop with hard and quick ground contact, great for increasing stiffness.

A better understanding the features of the stress-strain curve can start to help to show how you can structure your thought process when looking to train tendons. Both in understanding the behavior of connective tissue under load, important and under appreciated aspects like strain energy, the elastic modulus, and the yield point, as well as the potential adaptions that are trainable like stiffness, CSA, and elongation. Enabling training to create tougher tendons, not just stiffer ones.

In the last part of this series we’ll go over periodization. What does training look like over the course of an off-season and in-season to help enhance and maintain tendon toughness.

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Studies mentioned in the article:

Arampatzis, A., Karamanidis, K., & Albracht, K. (2007). Adaptational responses of the human Achilles tendon by modulation of the applied cyclic strain magnitude. The Journal of Experimental Biology, 210(15), 2743–2753. https://doi.org/10.1242/jeb.003814

Fu, B., Qian, Y., Wang, Y., Fang, J., Gu, Y., & Zhang, X. (2026). The effect of exercise training modalities on the morphological and mechanical properties of the Achilles tendon: A systematic review and network meta-analysis. Frontiers in Sports and Active Living, 8, 1782503. https://doi.org/10.3389/fspor.2026.1782503

Fouré, A., Nordez, A., & Cornu, C. (2013). Effects of eccentric training on mechanical properties of the plantar flexor muscle-tendon complex. Journal of Applied Physiology, 114(4), 523–537. https://doi.org/10.1152/japplphysiol.01313.2011

Kubo, K., Ishigaki, T., & Ikebukuro, T. (2017). Effects of plyometric and isometric training on muscle and tendon stiffness in vivo. Physiological Reports, 5(15), e13374. https://doi.org/10.14814/phy2.13374