The Scapula – Do we actually change kinematics?

Guest Article by Dr. Patrick Welsh

An overhead athlete presents with what appears to be a right subacromial impingement. On observation of shoulder abduction, you note “early” winging of the scapula on the symptomatic side. Therefore, due to a lack of scapular upward rotation, posterior tilt, and external rotation, the supraspinatus is being “impinged” by the underside of the acromion, right? And if I improve the scapular motion, the supraspinatus won’t be impinged and the pain will go away, right?

While this seems like a logical thought process, in actuality the story may not be that simple. In order to address this question, we need to first establish a few definitions. According to the most recent consensus on scapular dyskinesis (Kibler et al. 2013), the authors define it as a general term that reflects the loss of normal scapular kinematics. It is neither an injury nor a musculoskeletal diagnosis and does not include resting malposition. Kinematics qualitatively describe the motion of objects without reference to the forces which cause that motion.

In 2002, an orthopaedic surgeon named Ben Kibler, performed a qualitative observational assessment whereby he classified dynamic scapular position into one of four types. This classification identified various deviations of the scapular borders compared to “normal” kinematics. But what is normal scapular motion? And at what objective point does normal become abnormal?

In injuries such as a long thoracic nerve palsy or a detachment of the rhomboids, it is easy to appreciate that scapular motion will be altered. These types of injuries are considered to be primary scapular pathologies (Kibler et al. 2012). However, we are more interested in the role of the scapula in injuries thought to be associated with scapular dyskinesis. It’s been reported that scapular dyskinesis is associated with 68% of rotator cuff injuries, 94% of labral injuries, and 100% of glenohumeral instability cases (Brantingham et al. 2011). It is important to note that these are purely associations and do not infer cause and effect. And before we can even be certain of these numbers, we need to know two things:

  1. How was it determined that these patients had scapular dyskinesis (see assessment below).
  2. What is the prevalence of scapular dyskinesis in these populations prior to the onset of shoulder pathology as it’s possible they do not differ from those with an injury.

Is Scapular Dyskinesis associated with other shoulder conditions?

It’s very common as healthcare practitioners to make certain assumptions about an injury based on 1. Asymmetry; and 2. Pain. However, when it comes to scapular motion, this line of thinking is problematic.

  1. Asymmetry – While the unaffected side can be a good comparator in some situations, we have to realize that a certain (and undetermined) amount of asymmetry is not only expected, but also a normal adaptation, especially in many overhead athletes (Struyf et al. 2011).
  2. Pain – While dyskinesis may be present on the painful side, scapular dyskinesis has also been found in asymptomatic overhead athletes (Tate et al. 2009).

Despite these limitations some studies have shown that when you use a valid and reliable test, those with scapular dyskinesis have an 8 times risk of experiencing a shoulder injury (Clarsen et al. 2014). Again, this is an association not causation.

Assessment

So how do we assess for scapular dyskinesis? We need to evaluate the scapular kinematics. According to the Scapular Summit (https://www.ncbi.nlm.nih.gov/pubmed/23580420) 3 tests are recommended.

  1. Scapular Dyskinesis Test (SDT) – This test involves 5 repetitions with weight (3-5lbs) in abduction and flexion (Figure 1). A positive test is the presence of obvious winging or dysrhythmia and has been shown to have good reliability and validity. However this test has not been validated in those with shoulder pathology!
  2. Scapular Assistance Test (SAT) – This test involves manually assisting the medial border of the scapula (Figure 2) with the intent of increasing upward rotation and therefore reducing impingement of subacromial structures. A positive test is a reduction of symptoms with overhead motion. While this test has good reliability (Rabin et al. 2006) and can increase the subacromial space (Seitz et al. 2012), there are no validity studies to support the use of this test and the increase in subacromial space does not differ between those with and without dyskinesis. We also don’t know if changing the subacromial space is what reduces pain, or if pain is reduced purely due to the sensory input from the practitioner (This is a topic for another discussion).
  3. Scapular Repositioning Test (SRT) – This test involves assisting the scapula in retraction and posterior tilt while testing the strength of the shoulder abductors (Figure 3). A positive test is pain reduction or increase in abduction strength. While this test has good reliability (Band & Deyle 2000), there are no validity studies to support this test in those with scapular dyskinesis and the strength improvement also occurs in healthy individuals.

 

                 Figure 1. SDT                        Figure 2. SAT               Figure 3. SRT

 

Movement Context

So while these tests may be the best we have to determine the role of the scapula in shoulder conditions, there are several factors that are not addressed. None of these tests consider the role of speed, fatigue, or the overall context of a given movement (e.g. overhead sports). Many of our athletes only experience symptoms when larger demand is placed on the body. So we need to interpret these findings with caution and remember that scapular motion is likely to be different in the context of a specific athletic movement or exercise. From a kinematic standpoint, the above tests only consider the motion of the scapula about the thoracic wall and do not consider thoracic wall motion about a fixed scapula. These movement scenarios require different motor skills and therefore performance on one of these tests cannot necessarily be extrapolated to other movements. Considering that by definition, kinematics is a qualitative evaluation of motion, would it not make more sense to qualitatively evaluate the scapula in a manner that is more representative of the demands of the athlete?

Do the scapular kinematics change?

Returning back to our patient with subacromial impingement. Let’s say we are convinced that scapular dyskinesis is a contributing factor to the problem and we’re going to implement some scapular-focused treatment and rehabilitation. A randomized controlled trial by Struyf et al. (2012) compared scapular-focused rehab to rotator-cuff-focused rehab in those with impingement. They measured baseline pain, disability, and scapular kinematics. The rotator cuff group received manual therapy, US, and band exercises targeted at the rotator cuff while the scapular group received scapular mobilizations, and scapular rehab (e.g. Y’s and T’s). At the end of 9 sessions and at a 3-month follow-up, the scapular-focused group had significantly greater improvements in shoulder disability scores and decreased pain compared to the rotator-cuff group. However, NONE of the scapular kinematic variables changed significantly in either group!!! So the scapular group got better with no change in scapular kinematics. The question we have to ask ourselves now is whether the dyskinesis actually had something to do with the impingement in the first place. Unfortunately we can’t know for sure at this point.

With this information, we can appreciate that the scapula may play a role in shoulder pathology, however a cause and effect relationship has not been established. Several factors (speed, fatigue, movement context) should be considered in your evaluation of the shoulder. Lastly, we have to consider the possibility that other contextual effects may explain the improvements seen when we target the scapula to treat associated shoulder injuries.

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Clay Court Preparation

The clay court season is an important time for the players on the professional tour and in junior tennis. This surface places a unique demand on the player’s body. The clay surface is more slick and slippery than the hard court and so the athlete needs to have the ability to stay balanced and react to the uneven bounces and footing. In addition, the player’s movement on the court will be slightly different than playing on a hard court and so they will need the prerequisite movement competencies in order to be as efficient as possible.

 

When competing on the clay, most players slide into their shots as opposed to using small stutter steps on the hard courts to set up for a shot (there are exceptions). A lot of players are beginning to slide on the hard courts, but this is typically done when they are sprinting to get to a ball. On the clay, the slide occurs more often.

 

The sliding can occur as the player sets up to hit the ball, after the player hits the ball, and even the combined before, during, and after the ball is struck. This unique aspect of playing on the “dirt” may lend itself to an increased risk in hamstring and/or groin (adductor) injuries if the player does not have the prerequisite competencies including tissue compliance and sufficient motor control. The sliding motion observed during play on clay courts imposes high eccentric loading to the lower extremity, specifically, to the groin and hamstrings (as seen in Figure 1). Typically, this form of loading occurs in a reciprocal pattern and subsequently the training must accommodate the pattern and loading.

 

Injury or intolerance to physical loading typically occurs if the athlete’s capacity is exceeded. Therefore, it is important to help train each athlete in order to build up their tolerance so that their capacity is greater than the demand imposed on the body.

 

There are a few considerations when determining the exercise required to accommodate the sliding motion in tennis:

 

  1. Interpretation of tension or stiffness
  2. Active joint articular control of the hip complex through the available range of motion
  3. Anatomical relationship between the rectus abdominus and the adductor complex at the pubic symphysis

 

Interpretation of Tension or Stiffness

With the slide comes the need for tissue compliance of the entire hip complex to eccentrically load, which involves but is not limited to the hamstrings and adductors/groin (Figure 1). In order for the central nervous system to accommodate tissue compliance through a demanded range of motion, one must possess the ability to control this entire range of motion. Tension or tightness can be experienced when moving through range for many reasons. One of the reasons for this sensation can be the brain perceiving a threat and in order to protect the body, it will produce a sensation of “tightness”.  This perceived threat is interpreted as, to a certain extent, insufficient control of the available range under demand, in this case the slide on clay courts. To understand tension a little better click here and here.

Active Joint Articular Control

Joint articular control should be attained through the entire excursion of said available range (beginning, middle, and end range). This means focus should be directed at controlling concentric and eccentric portions of exercises. A few exercise sequences for the hip complex that takes this into account can be found here and here. Remember, the player needs to be able to get into the position, but also has to get out of the position.

 

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Figure 1. Tissue compliance of the hip – Opposite hip flexors to opposite hamstring complex (left picture) and adductor complex to opposite adductor complex (right picture)

Anatomical Relationship

There is a strong anatomical relationship between the adductors and the core (Figure 2). This fascial connection can be seen as an “X” pattern across the pubic symphysis between the rectus abdominis and the adductor longus. Therefore, there needs to be a focus of not just isolating the hip, but also combining it with the abdominals. The intention is to develop load tolerance at the pubic symphysis to accommodate force transfer between the groin and the abdominals. Two examples of exercises can be found here and here. If one of these muscles is not doing their job, then there is a chance that its opposite sided muscle in the fascial connection may have to work even harder which may increase the risk of exceeding the tissues threshold for load.

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Figure 2. Front Functional Line (left picture) and Adductor Longus (AL) crossing over to Rectus Abdominis (right picture) (Norton-Old et al. 2013)

 

Clay court tennis enhances and challenges some of the aspects already involved with on-court movement due to the lack of traction and inconsistent bounces. It is therefore that much more important to challenge the body’s ability through various lines of tension during exercise protocols.  The intent for exercises given should take into account all the demands placed upon the athlete with the goal for the athlete to be more resilient and hopefully see transferability onto the tennis court.

 

 

Training For the One-Handed Backhand

 

Strength, power, speed, agility, and endurance are a few elements needed in order to become a high-level tennis player. Depending on your technique (one-handed backhand vs two-handed backhand) and game style (baseliner, serve and volleyer, counter-puncher, etc. …), the capacity requirements to tolerate certain physical demands may be different. With that being said, a proper training regimen and strength and conditioning program should take all of these factors into account.

 

When looking at a one-handed backhand, the posterior chain (Figure 1) is highly active. The posterior chains are recruited to execute, with proficiency, the backhand in tennis. During the preparation phase of the backhand, the stretch on the posterior chain stores energy necessary for racquet speed during the swing phase of the backhand. This line is responsible for maintaining posture and the required movement pattern. With a closed stance one-handed backhand for a right handed player (Figure 3), it can be said that there is more of an ipsilateral loading bias, right hip to right shoulder interaction (superficial back line). Whereas with an open stance or if the player is hitting off their back foot, there is more of a contralateral loading bias, left hip to right shoulder interaction (functional back line) (Figure 2 left image).

 

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Figure 1. Posterior Chain – A. Superficial Back Line: Paraspinals (back muscles), hamstring, gastrocnemius (calves), plantar fascia. B. Functional Back Line: latissimus dorsi (lats) and contralateral gluteus maximus.

 

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Figure 2. Open Stance Backhand Variations: Right Hander – emphasis left hip to right shoulder (left image) vs Left Hander – emphasis right hip to left shoulder (right image).

 

During the closed stance one-handed backhand in a right-handed player (Figure 3), there is an initiation of right hip extension leading up to the point of contact and carrying through and past that point of contact. This motion will be dependent upon where the point of contact is in relation to their body, i.e. below knee level or above hip level. During all of this, the right shoulder complex is essentially going from horizontal adduction into horizontal abduction (with other planes of motion as well).   During the open stance or if the player is hitting off their back foot, there is an initiation of left hip extension with the right arm going from horizontal adduction to horizontal abduction (Figure 2 left image).

 

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Figure 3. Closed Stance right one-handed backhand with emphasis on right hip to right shoulder.

 

Combining the knowledge of the backhand mechanics and functional patterns, it is the role of the strength and conditioning coach to prescribe exercises that challenge the various forms of the posterior chain with the emphasis on certain patterns: right hip to right shoulder, right hip to left shoulder, left hip to left shoulder, and left hip to right shoulder. Two exercise sequences that take all of this into consideration can be found here and here. Both exercises work on motor control and coordination while challenging the body’s spectrum of stability involving the posterior line. In addition, the core is challenged with anti-flexion and anti-rotation moments.

 

Proper technique of these exercises is key to enhance proficient use of the posterior chain during the backhand in tennis. These exercises require pre-requisite factors including lumbopelvic control and posterior chain tissue compliance. Certain athletes may require regression or lateralization before attempting these exercises. There is no one size fits all approach.

Learning vs Performance: Which one do you emphasize?

Ask yourself… if you had to learn a new skill or movement, how would you go about it? And how would you monitor the progress of acquiring that skill or movement?

Repeating without repeating is a mantra many movement educators ascribe to. Today I am going to review the concept of what it means to repeat without repeating, or more specifically learning during repetition.

As teachers, instructors, mentors, etc. … our role is to equip the learner with the knowledge and or skills that will be durable and flexible over time. If what you learn is durable, it means that you can access this knowledge or skill overtime when it has been not been used for some time (i.e. recall or relearn). Also, if what you learn is flexible, this would imply that knowledge and or skill is accessible across a variety of conditions or scenarios that goes beyond the original condition by which the knowledge or skill was taught (classroom or at practice).   Here I am referring to learning or skill acquisition, not performance of how well you learned or execute the skill.   Here is the reality:

“You can learn and not demonstrate result in performance; but you can see great gains in performance and not exhibit much learning”

For the minimalist, who like to cut corners and just have a tendency to do as little as possible…the short term success in performance is your bread and butter! But be forewarned that this may come back to haunt you when you get hurt and are side-lined to rehabilitate the injury or you move up in competitive ranks and now play with the “elite of the elite”.   Great coaches and therapists see this all the time. An athlete gets hurt and struggles to get back to pre-injury status and continue play, or elevate play to an even higher level. The other scenario, the athlete graduates or is promoted to the next level and struggles to keep up with the tempo of play, keep up with the level of game IQ, or even keep up physically. This comes down to, in part, to an athlete’s inability to learn the necessary knowledge and skills to complement the performance necessary to compete.  

Remember, learning is not performance and performance is not learning. Far too often athletes view the short term success in performance (performing faster, stronger, more accurately, personal best times, etc.…) as learning, but to sustain athletic ability, adapt to competition, and augment the injury management process, you have to view learning as the focus of training.   Performance should never be about just being durable, possessing tissue tolerability, acquiring mobility, and developing strength, endurance, power, and agility.   But unfortunately, it has and continues to be so. To be great a great athlete requires time and dedication to time to learn.

Let’s review for a moment:

Learning – The primary objective is to resist forgetting how to execute a skill efficiently and consistently. Another objective is possessing an accelerate rate to relearn a skill when it has not been used for some time (i.e. returning from offseason not playing your sport and entering training camp needing to re-acquire the skill to prepare for the next competitive season).   The ability to retain a skill, in this case movement, the athlete must possess a relatively permanent behaviour to support the learning effect.

You cannot retain a skill that was never learned!!!

Keep in mind that dedicating to learning a skill or movement will compromise performance in the short term but profit the long term success.   Learning by in large occurs during practice or training. With this said, there are a few guidelines to learning that need to be considered:

  1. Do not be afraid to make mistakes or errors – research demonstrates that errors made when learning or mastering a skill hinders performance in the short term, but in the long term may be needed to retain and apply the skill efficiently. The caveat is that the athlete understands and appreciates the value the error has on the learning process in order to make changes. Nobody wants to make the same mistake twice!
  2. Active participation and minimal intervention – early physical assistance to demonstrate or create an awareness of what needs to happen (i.e. coach placing a golfer’s club through the correct plane of motion in the back swing). However, this should be done sparingly by coaches. Research consistently concludes that retaining the information is low when too much guidance is given.   The athlete needs to actively explore “how to” move on their own.   This process will enhance long term retention within the parameters of what the athletes own perceptions of his/her ability.
  3. Learning of new or revisiting old skills – regardless of the skill in this situation, it requires cueing to elicit if learning has occurred. Meaning, has the athlete retained what needs to be acquired to execute a skill or can they relearn at an accelerated rate to achieve previously acquired skill?   You cannot use performance to demonstrate learning in these two scenarios. The athlete needs prompting to execute the skill in a contextual manner. Learning a skill or movement without purpose is not retained.
  4. Testing is key to assessing if a skill is being learned I already stated that depending on the skill, performance is not an ideal tool to evaluate whether a skill is learned. Performance is used to assess the acquisition of a skill in a contextual manner (i.e. throwing a curveball for a strike on a 0-2 count) if the process has been completed and testing demonstrates adequate knowledge and understanding to be consistent and efficient.   However, for the skills that are in the process of being acquired (being learned) then testing is the most appropriate tool to assess the progress. Testing can be performed in a number of methods:
    1. Reproduce the skill to be learned – coach requests “throw me a curveball!” – Athlete should throw a ball that has a trajectory that loops or curves and in the strike zone as requested. This is a physical competency – can the athlete physical throw a curveball?
    2. Retrieve the skill – the athlete must select when the most appropriate moment to throw a curveball is in the context of a game situation. This is not so much as physical as it is mental, implying a decision making process that involves understanding the application of the skill in the context of the game. This evaluates the athlete’s understanding of the use or application of the physical skill and be able to physically execute the skill based on this decision making process.  Retrieval can also imply the athlete exploring options about how to generate a movement as opposed to a selected movement instructed by the coach or instructor.
    3. Present the skill without reproducing it – requesting the athlete to explain (verbally) how to throw a curveball, what the most common errors with executing a curveball are, and when to throw a curveball. This will assess the athletes understanding and interpretation of the skill needed to be learned.   This method is commonly neglected and replaced with reproduction or retrieval assessments.

You cannot learn what you do not understand.

  1. Having some difficulty in the learning process is good! –confronting and resolving challenges in the acquisition of a skill is important. This allows the athlete to effectively link new information with existing information or understanding. This enhances the long term retention of a skill or movement, but more so exposes the athlete to understand and recognize the nuances of the skill or movement.   Knowing the “in’s and out’s” is critical making the necessary changes in real time when in competition when errors arise.   Just being efficient and consistent is not enough. If I can quote one of the best lines I have ever heard:

The difference between elite and playing at the highest level is that my B-game has to be better than most A-games to be successful!”

Now that is one smart athlete! But it is true. Athletes… you will never have your best performance every moment of every game of every season.   Performance fluctuates too much. It is volatile in many respects.   There are too many variables that influence the outcomes (weather, team, tactics of sport, emotions, and officiating). The only consistency is your ability to train with intent and focus.

Performance – temporary fluctuations in behaviour or knowledge that is observable and or measurable during or immediately after acquiring the behaviour or knowledge.  It is about putting the newly acquired skill or existing movement or knowledge to the ultimate test (competition) which will determine how well you performed (how much weight lifted, how fast you threw, how far you jumped, etc. …).   Because performance and competition are never the same experience, team, or condition, what you did not learn and the ability not to recall will hinder future performances. To stand the test of time and continue to improve in the quest to be a better athlete, learn first, perform second, and do not cut corners!

Ask yourself in the next practice or training session, what are you doing?   Are you going through the motions or are you attempting to learn or extract something that can make future athletic endeavours better?   Are you the person that just stacks weight on a bar and pounds out 5×5 because that is the program? Are you throwing in the bullpen at 75% velocity because you are told to?   Are you doing mobility work to increase range in only one particular way? What is your practice or training session really preparing you for?   Better yet, what are you using to monitor that your acquisition of a skill or movement is being achieved?

I am harsh, but a realist. Far too often I treat and train athletes that are afraid to make errors or are training to avoid these errors. The reality is that those errors are more important than performing well sometimes. Errors are rich with information about how and why you do what you need to do. What does performance tell you? A lot!!!! You make an abundance of mistakes and errors during an actual game or competition. Those that perform well recover from those errors and make the necessary changes and corrections.

If you train what is ideal and comfortable and predictable (PERFORM) AND not learn how to make adjustments in real time and correct errors or mistakes when encountering unknown variables or uncertain events (LEARNING), then how is it you expect to make adjustments during competition? Competition is to a large extent about unknown and not necessarily predictable events. You cannot learn and adapt to something you have not exposed yourself to first! To retain a skill or knowledge or be able to transfer this same skill or knowledge to an unknown condition or event requires that learning or the acquisition occur regardless of performance success.

Learn to explore the potential boundaries of your skills and knowledge. Take and obtain valuable information about how to become better when errors occur. The structure of practice or training influences the learning effect as well. Here are some considerations:

  1. Random or Distribute Practice/Training – let me just state for the record, there are two forms of practice BLOCK and RANDOM. Block practice is repeating the same thing over and over; which is great for short term recognition and familiarization of the skill or knowledge. Block practice is shown to have poor long term retention. To enhance the long term retention, random practice is suggested. Random practice implies that the order that the skill/knowledge is executed or learned be distributed in an order that fluctuates (randomization). Distributing means that if there are a number or skills (i.e. tennis forehand, backhand, serve, drop shot, etc.…) then allocating time in the same practice to practicing each is beneficial to the learning process in the long term. Yes, performance for each is reduced, but the key is to retrain and apply the skill under any circumstance not performing it well in the short term.

When you practice, the repetition should be about gaining experience or information about how and when to control the tools (motor control, strength, coordination, power, speed, etc. …) to produce movement or a sports specific skill in the context of the goal or training objective.

  1. Space practice out – take time between practice sessions, also known as Spacing Effect. This rest between sessions allows for resistance to forgetting and long term retention of the skill or information. Research demonstrates that massing or chunking large blocks of time to practice improves short term retention and initial performance gains but long term retention and forgetfulness is high. So do not spend countless repetitions repeating the same skill over and over, every day! Rest enhances the learning!

 

  1. Learning will impair performance so commit to the process of acquiring the skill and knowledge.   Research continues to demonstrate that before you get better (perform) learning trumps all and you will struggle to execute efficiently. Success is about the long term and not always about here, now, and today. Check the ego and let go of the instant gratifications.   Work hard to develop and learn your sport skills and the associated knowledge to be able to call on them later on under any circumstance, known or unknown.

 

Bottom line, if you want to perform well across time and sustain such efforts then remember that learning requires you to practice with intent and conducive to the process.

The table below summarizes the key practice or training variables that influence learning and impact on performance.

Practice-Training Variable Benefit to Learning Process Consequence to Performance
Reinforcement (physical assistance)

 

 

 

                                                 

Used early in learning process to familiarize the athlete.

Reduces error production

Increases confidence

Enhances short term performance

Enhance long term retention of skill and or knowledge

Long term use impedes retention and increases forgetfulness
Block Training – repeating the same skill over and over Used to familiarize the athlete to enhance confidence and awareness

Increases short term performance

Poor retention and lowers rate of relearning in the long term

Long term performance is limited

Random Training Enhances long term retention, at expense of short term performance struggles High error rate during short term performance
Space practice out – recovery or rest between sessions Allows information and skill to consolidate (“sink in”) that promotes retention and transfer Poor retention and lowers rate of relearning in the long term

Long term performance is limited

Interleaving or distributed order Performing multiple to be learned skills or implementing multiple parameters for execution permits enhances retention and retrieval. Causes Contextual Interference – conditions or parameters that interfere with the acquisition of the to-be-learned-skill with other skills that depress performance in the short term.
Testing                    Identifies either physical competency (execution) or cognitive competency (understanding) or both to understanding the skill Athlete focuses on performance rather than the process of error production and correction of such errors.

At first, practice to learn, once learning has been achieved practice to master your skill and knowledge.

 

Reference:

Lee T, Swanson L, Hall A. 1990. What is repeated in a repetition? Effects of practice conditions on motor skill acquisition. Phys Ther. 71:150-156.

Soderstrom N, Bjork R. 2015. Learning vs. Performance: An Integrated review. Assoc Psycho Sci. Vol 10(2): 176-199.

Scapulothoracic Articulation vs Thoracoscapular Articulation and The Tennis Serve

The tennis serve is an extremely complex motion, which utilizes the body’s full kinetic chain. The entire service motion, from bouncing the ball to the follow-through, is of the utmost importance in which all of the sequential and coordinated actions need to be analyzed. One must take into consideration the motion before ball contact, at ball contact, and after ball contact.

 

In order to get to the ever-important contact point, from a biomechanical standpoint, the scapulothoracic articulation (STA) performs a beautiful dance as it goes through numerous motions in different planes.   These motions occur with the scapula moving on the thoracic spine, but also, with the thoracic spine moving about the scapula. From a rehabilitation or strength and conditioning point of view, this needs to be addressed.

 

First of all, does the athlete possess the motor control and coordination to move the scapula independently over the thoracic spine? Secondly, does the athlete possess the motor control and coordination to move the thoracic spine about the scapula? The athlete should have the ability to dissociate the articulation with both types of movement.

 

Most of the exercises that I see being prescribed or performed by tennis players, including many top 100 world ranked players, focus on the scapula moving about the thoracic spine, ie. reverse fly, prone 1-arm trap raise, etc., but not the motion of the thoracic spine moving about the scapula. During the cocking stage (stages according to Kovacs and Ellenbecker, 2011), there is an acceleration of the thoracic spine about the scapula. This motion calls for exercises focusing on the dissociation of the STA with the thoracic spine moving about the scapula. An example of such an exercise can be found here.

 

Remember, when dealing with athletes, one must be aware and have knowledge of the sport that they are dealing with.   Having this knowledge allows for the practitioner or strength coach to prescribe more robust exercises related to the sports biodynamics.  

Tension Part 2: The Appreciation

In Tension Part 1: Good and the Bad, we discussed that tension may not always be what we think. Understanding the origin of tension and the purpose it has on human movement is critical to developing, treating, or training the athlete.

As a review, the definition of tension – an internal state of tissue that is maintained continuously, also known as a partial contraction. This exists at rest in a relaxed state and increases with stretch.

Physiologically, tension is monitored by the muscle spindles (stimulated with a stretch) and golgi tendon organs (stimulated with external load).   To truly understand tension, the body has to be challenged to create a response – MOVEMENT!   Muscle spindles have three types of gamma fibers that detect tension.

Type 1 – detects unfamiliar and or new movement. You will experience or perceive tension in the tissues involved with movement!

Type 2 – detects familiar and accustomed movement. Not a lot of tension will be experienced or perceived necessarily.

Type 3 – detects unlearned, unfamiliar, and or new movements. Very similar to type 1 fibers and tension will be experienced.

Therefore, if the movement is new or novel to the athlete, tension is likely and because it is not a learned movement, the observation of a flaw or dysfunction could be interpreted. But this may not be the case.   The solution… give the athlete an opportunity to practice (fast learning) to permit the gamma fibers (type 1/3) to accommodate or adapt to the movement.   This also means you don’t stretch or treat this form of tension unless clinical reason would suggest so.

Furthermore, the concept of tensegrity, a concept that has been around in the fascia world for some time now, epitomizes the notion that tension is maintained continuously.   Tensegrity is a degree of tension throughout the elaborate and comprehensive fascial network that provides continuous feedback about where the entire body or limb is in space (kinesthetic awareness). Moreover, kinesthetic awareness is a function of adequate proprioception (limb position, limb movement, and muscle contraction). Therefore if proprioception is inadequate with movement, tension can be elevated in the body.   With this all said, excessive tension can be a by-product of inadequate proprioception. Said another way, excessive tension can be perceived due to altered joint control and multiple body segments lacking coordination through a movement pattern. Remember, fascia plays a role with communicating between remote body segments and supplying sufficient tension to regulate movement, which ultimately provides kinesthetic awareness. This form of tension is good!

One has to understand that phasic and tonic muscles respond differently when it comes to producing a contraction. Tonic muscles are responsible for controlling joints during movement, whereas phasic muscles are responsible for generating force to create movement. Tonic muscles when deconditioned or dysfunctional will present as hypertonic or hypotonic (low tension). Whereas phasic muscles will present as being hypertonic if deconditioned or dysfunctional.   Tonic muscles respond to joint (dys) function which is consistent with the role of such muscles. However, phasic muscles respond to tonic muscle function during movement. The interplay between the two types of muscles needs to be accounted for during the movement assessment, for example, is the movement strategy a control or coordination issue or a capacity issue (phasic muscles).

Furthermore, tension can also be interpreted by receptors called nociceptors. These receptors are designed to monitor for threats to the body (thermal, chemical, and mechanical forms).   In the health and fitness world we tend to interpret mechanical forms of threat. This is in the form of aberrant, unlearned, unstable, and dysfunctional movement patterns.   Depending on the duration of the altered state of movement, this can lend itself to ingrained habits. As a result, even if the movement is corrected, but tension is still perceived in a threatening way, the nociceptors may not have adapted to the change and require time for a new perception to be created!

So on to the test I had asked you to go through with hamstring tension:

“The next time you experience or come across hamstring tension during a hamstring stretch I want you to consider the following: What happens if…”

  1. You provide resistance in either adduction (groin) or abduction (glute) during the stretch of the hamstring?

EXPLANATION: If providing resistance to either or both muscle groups and the result was reduced hamstring tension, then one possibility for reduced sensation of hamstring tension was due to an improvement in hip centration (joint articulation control through movement) which could reduce the threat (nociception). So from a rehab/treatment standpoint, stimulate the muscle(s) that offset the tension with motor recruitment strategies (isometrics, electrical stimulation, etc.). Now, if applying resistance increases tension to the hamstring, this would suggest that excessive tension was created during resistance and resting tension of the abductors and or the adductors was high to begin with and needs to be addressed (stretch, self-mobilization, clinically evaluated).

  1. You perform isometric contraction of the hamstring (minimum of 10 seconds at 80% maximal effort for 5 repetitions) and reassess?

EXPLANATION: The contraction induced a stretch reflex and modulates the threshold of sensitivity of the muscle spindle to perceiving a stretch. So what?? Isometric contraction at, just below, or graduated through increasing range will allow the body to accommodate the stretch perception so that it is more tolerable to a stretch.   The key here is the intention of effort which needs to be >80% effort to provide sufficient neurological input to stimulate the muscle fibers and enhance the irradiation principle (the spread of neurological stimuli to the working muscle or muscle groups).

  1. You change your posture. For example if you assess the hamstring standing (i.e. toe touch), perform instead supine or lying your back?

EXPLANATION: The postural demand places different load demands on the system that the body must accommodate. This will provide insight into the athletes preferred methods of training and stretching. Moreover, this also provides critical information about what positions the athlete does not tolerate and insight into the lack of variability of motion he or she has. Movement variability is a concept that defines the available options an athlete possesses to move efficiently. The less variation in training (movement direction, load, contraction types, volume, labile vs. non labile conditions) will expose the athlete’s inability to accommodate certain positions and tasks because they have created a contraction history (thixotropic effects) based on how they move. This contraction history is the body’s way of adapting to repeated exposure to stimulus (exercise, work tasks, posture, etc…). The body will move well in directions it is used to (tissue will be compliant with appropriate tension to permit motion) vs. other unaccustomed positions (tissue will be less compliant – thickened and excessive tension that does not permit appropriate motion).

  1. You perform a core exercise of your choice and then reassess the hamstring?

EXPLANATION: This is similar in principle as the first scenario with the abductors and adductors. The important note to take from the core exercise is that the stimulation of the core to facilitate control of lower extremity movement (in this case SLR) reduces the nociceptive input (threat due to an uncontrolled pelvis and core musculature) that alleviates a reflexic response of hamstring tension.

  1. You perform a stretch or mobility exercise to the ankle?

EXPLANATION: This scenario provides insight into the interconnectedness of tissues within the body especially at or near attachment sites. In this case the distal femur and proximal tibia, which we also call the back of the knee!   The interface between the distal hamstring and proximal gastrocnemius is a common site for excessive tension to be identified. Whether this is the skin itself, crural-tensor fascia or the actual interface, it can be challenging to know which exactly the culprit is. Nonetheless, understanding the anatomical relationship can provide insight. In this case the hamstring tension can be influenced by the calf tension because of the anatomical relationship. Therefore, inducing a stretch reflex response via the calf (dorsi flexing the ankle) may in some cases alleviate hamstring tension.

So, now that we have some explanations as to what may be going on, do you remember what happened?   If nothing changed that is also an acceptable outcome of any of these scenarios. The lack of change can represent a couple of things:

  1. The stimulus applied (resistance, stretch, activation of a particular region) was insufficient to produce a change. This may imply that more bouts of resistance or longer stretch duration or multiple sites of activation are necessary to create a change.
  2. The stimulus applied was appropriate and sufficient but the issue maybe the hamstring itself! Yes, that’s right. Now you have concluded that the issue at hand is actually the hamstring and not something else, and so the athlete needs to be clinically evaluated (fibrosis, significant neurological injury or other form of soft tissue pathology).

The intention here is to have you evaluate and understand that tension may be a by-product of poor kinesthetic awareness as a function of altered function of the surrounding structures. The goal was to have you appreciate that there can be a multitude of reasons why the hamstring was tight and that a subtle change can be a big difference in alleviating the tension.   Remember not all tension is bad. Tension may be good as the body is attempting to protect itself from further harm.   If the body did not regulate itself this way there would be more injuries!

In the AMA Course Series we explore the various sources of tension that compromise movement and narrow down what can be managed with simple strategies and when a referral for clinical consultation is most appropriate.