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A Swimmer's Guide to Pain

Take Home Points:
  1. How coaches talk to athletes about injuries may have an impact on return-to-sport timelines
  2. Coaches and parents should have a basic understanding of pain science to best communicate with swimmers
  3. Fear of movement can be crippling setting off a vicious cycle of pain and disability
  • I have a vertebra out of place
  • My back is out of alignment
  • My knees are bone-on-bone so I can’t do breaststroke
All of the above are common ways to describe typical injuries around the pool. And while there are often grains of truth in such statements, a narrow focus on the structural elements of injury inevitably ignores the psychosocial components in pain. This is one area where coaches and parents can play a key role in talking to injured swimmers and reinforcing what contemporary medical professionals understand about pain science.

Now, the purpose of this is not to dismiss the role of structure in causing pain. In fact, the extreme statement of “pain is all in your brain” is equally counterproductive to injury healing in athletes. Yes, certain pathologies are likely to induce pain, particularly when lesions occur in particular nervous system structures. However, what is unfortunate is that a misunderstanding of pain can thwart even the most carefully planned treatment and exercise regime.

Quite simply, the feeling of pain is driven by the body’s perception of threat. We know that
perception is key, not merely structural damage, as many studies have shown that pain-free subjects can have structural damage in similar rates to painful subjects, particularly for repetitive use conditions (trauma is a different story…). We have discussed this point previously in several posts including for:
Recently, Finan (2013) compared knee osteoarthritis patients classified into “high” and “low” severity. Somewhat surprisingly, those with high severity damage experienced less pain than those with low severity damage, as those with less damage were actually found to have more pain! There are several reasons why this may be the case, but the take home point is that damage is not automatically linked to pain. As such, coaches and parents must not mislead swimmers with a narrow focus on the injury and instead shift the focus to more productive areas such as function, mobility, and progression.

So why do some swimmers feel pain and others don’t, despite similar structural makeup (damage or lack of damage)? One explanation is that everyone has different sensitivities. Each swimmer’s sensitivity is driven by a myriad of factors such as previous injury, personality, training load, stroke biomechanics, among other factors. As pain scientist David Butler wrote to one patient suffering shin splints,

“Even a few years after an injury the brain holds memories of serious injuries and can react over time – almost trying to heal it again so it puts in a bit of useful swelling there which can irritate things. It gets a bit compounded when treatments don’t work or make sense and you start to worry - worry can make can make things more sensitive too. But this is all good – it will go.”


Many swimmers (and patients in general) are more comfortable with discrete explanations of structure. Unfortunately, a misunderstanding of the psychosocial elements of pain can often prolong the rehabilitation process as swimmers, coaches, and parents obsess about the structural elements of injury with laser focus! This commonly results in perpetuation of injury, creating a vicious cycle in which the swimmer is unable to successfully progress through rehab, despite best practices being employed via treatment and exercise. Ultimately, a proper understanding of pain can help guide swimmers back to function if injury strikes.

If you are looking for more information on pain and injury at the shoulder, consider purchasing the Swimmer's Shoulder System.

  1. Finan PH1, Buenaver LF, Bounds SC, Hussain S, Park RJ, Haque UJ, Campbell CM, Haythornthwaite JA, Edwards RR, Smith MT Discordance between pain and radiographic severity in knee osteoarthritis: findings from quantitative sensory testing of central sensitization. Arthritis Rheum. 2013 Feb;65(2):363-72. doi: 10.1002/art.34646.
Written by Allan Phillips is a certified strength and conditioning specialist (CSCS) and owner of Pike Athletics. He is also an ASCA Level II coach and USA Triathlon coach. Allan is a co-author of the Troubleshooting System and was selected by Dr. Mullen as an assistant editor of the Swimming Science Research Review. He is currently pursuing a Doctorate in Physical Therapy at US Army-Baylor University.

Friday Interview: Dr. Craig Smith, DPT discusses the Functional Movement Screen

1. Please introduce yourself to the readers (how you started in the profession, education, credentials, experience, etc.).
My name is Craig Smith and I am physical therapist/researcher. My interest in injury screening was the result of numerous injuries in high school and college athletics. My ultimate goals is to prevent other athletes from injury so they can enjoy sport without restriction. I began my work in healthcare as an exercise physiologist working in cardiac rehab before returning to school to become a therapist. I work with Dr. Nicole Chimera PhD, ATC  
(http://www.daemen.edu/academics/divisionofhealthhumanservices/athletictraining/faculty/Pages/NicoleChimera.aspx) and Dr. Meghan Warren, PT PhD (http://nau.edu/CHHS/Physical-Therapy/Directory/Warren/). In the past couple yeas, our team has investigated several types of movement screens that have been reported previously in the literature.

2. You recently published an article on the the reliability of the functional movement screen (FMS). Could you simply explain the FMS and why it is important know if it is reliable?
The Functional Movement Screen is a series of 7 movements scored using an ordinal scale of 0-3 with 3 screening tests to determine other possible pathologies. The screen was developed to be included prior to participation in sport in order to prevent injury based on movement impairments. A more complete explanation can be found at http://www.functionalmovement.com/.

With any screen, reliability must be determined because the validity is predicated on reliability. This means in order for a screen, test, or exam to be valid for whatever it is testing, the test must also be reliable. Prior to using the FMS in our research, the team decided we needed to determine reliability with varied clinicians during live testing.

3. Could you briefly explain your results?
Our work supported previous reports that total composite score of the FMS was reliable; however we also found that the hurdle step was not reliable in a sample of recreationally active young adults. We used clinicians with varied experience (a biomechanist, a physical therapy student with no FMS experience, a physical therapy student who had performed over a hundred screens, and a strength coach certified with FMS). Our findings indicated that a 2 hour training session was sufficient to ensure reliability.

4. Simply, do you think the FMS would be helpful for swimmers for preventing injuries?
Our team recently completed a study that found no relationship between non-contact injury and FMS performance in a sample of Division 1 collegiate athletes, which included swimmers. We presented these findings at the American College of Sports Medicine Conference in Indianapolis this year. This is in contrast to other studies that have related injury to scores below composite FMS of 14. So, yes it may be possible that the FMS could identify some general movement impairments, although large studies using swimmers have not been conducted. 

5. A recent study by Chapman et al. suggests the FMS could help predict performance, do you think this is true for swimmers?
According to Chapman et al., this is certainly a possibility, but more research is needed. The purpose of the FMS is not to determine performance, but as a screen of future injury risk] risk of future injury. At this point, our team has not investigated this area. Our primary focus is to determine risk factors that predict non-contact injuries.

6. Do you think swimmers require any different form of testing due to the nature of the sport?
Every athlete should be screened first for previous injury history prior to participation or current musculoskeletal condition. Currently, there are no screens that are specific to swimmers. A new screen that we will be investigating in the future is the upper extremity Y balance Test. http://www.ncbi.nlm.nih.gov/pubmed/22228174

This screen would be able to assess upper quarter asymmetry and control, which could be critical in a sport that requires overhead mobility while maintaining stability. Further, screening for scapular dyskinesis is critical in this population. This can be performed with different strategies including the lateral scapular slide test or scapular dyskinesis test.

7. What are still some uncertainties for injury prevention in sports?
There are many uncertainties for injury prevention in sport, which is why so much research is being conducted in this area. No single screen has clearly predicted injury across all sports and gender. A summary of collegiate injuries over 16 years by Hootman et al. found that non-contact mechanisms account for 17.7% and 36.8% of injuries during games and practices, respectively. Further, analysis by several different groups have found that 70% of anterior cruciate ligament injuries are non-contact in nature. Clearly defined risk factors for non-contact injury mechanisms with different screens are needed first followed by intervention studies that show these factors are modifiable.

8. How big a role do you think genetics play in injuries?
Multiple extrinsic and intrinsic factors have been related to increased risk of injury in the literature. These include playing surface, bracing, shoes, gender, previous injury, poor balance, poor movement, age, foot type, and BMI (to name a few). This is not an exhaustive list. The critical factor in reducing injury is determining which injury risk factors can be identified and modified, thereby reducing the amount of injuries. Does genetics relate to injury? Most likely it does. Can we identify the genetic factors? Once again, we most likely can identify the factors but the cost for large scale implementation would be prohibitive except for well funded teams and individuals. Can we modify genetic factors? I submit that in most cases we cannot, which reduces genetics as a priority in our line of research.

9. Some argue injuries will always occur, if this is true, why is the FMS and other screening test important?
Participation in sport is inherently risky. When an athlete is working at top capacity against another athlete, injury can happen. Our research is meant to find risks factors associated with non-contact mechanisms. The analysis by Hootman et al. indicated this was an area that could reduce the rate of injuries and should be the focus of future research.

The argument that injuries will always occur does not mean that certain injuries cannot be prevented or risk factors should not be identified. Research surrounding anterior cruciate ligament injuries has shown that screening and intervention reduces that relative risk of future injury. If you consider that the surgery and rehab can cost thousands of dollars and dramatically increase the likelihood of developing osteoarthritis in the future, then screening for risk and appropriate interventions to reduce risk will be critical and worthwhile.

10. What research or projects are you currently working on or should we look from you in the future? 

Our team is currently working on several publications from our initial work with Division 1 collegiate athletes and initiating another study with different screens with female athletes in an attempt to better predict non-contact injuries.

Thank you!

Continue Swim Training During an Injury

When I consult with club teams or individuals I am continually surprised to see how many injured swimmers are not training! Now, I know this opposes the view of many physicians and rehabilitation specialist, who suggest rest and medication during any injury, but even during an injury, it is essential and possible to train!

For example, let us discuss someone with a shoulder injury. Let’s say a swimmer has should pain and they are diagnosed with impingement. We've discussed ad nauseum about the presence of structural abnormalities in asymptomatic athletes (See Radiologic Imaging and the Asymptomatic Athletic Shoulder and Abnormal MRIs in Tennis Players), but let us pretend the athlete actually has an acute shoulder impingement. 

For optimization of swimming, the athlete cannot miss anytime from the water. Now, this doesn't suggest doing heavy volume or even using the injured arm, but getting in the water and swimming without pain is often possible. Pretend the athlete has shoulder pain with the easiest of strokes. Then, it is key to have the athlete kick in a position (likely on their back in streamline or with their arms at their side) to allow continued in water improvements. Many dismiss this form of training, but the arm - leg cross transfer can help an athlete maintain their physical work capacity during an injury. Numerous studies suggest training only the arms (via an arm crank) or solely the legs (leg cycling) will improve performance in both the arms and legs (Lewis 1980; Pogliaghi 2006; Bhambani 1991; Loftin 1988; Tordi 2001; Roesler 1985; Magel 1978).

Issurin (2013) notes the following benefits of arm – leg cross transfer:

  1. Training with either arms or legs produces a transferred cross effect on the untrained limbs—on average 32 % of the gain recorded in the trained limbs (i.e., specific effect) with a wide range of variation from 5.7 to 93 %; these large variations reflect the high variability of training groups in the different studies, which included young athletic subjects or middle-aged and elderly persons.
  2. The specific effect producing by arm training is usually much more pronounced as compared with leg training; this can reflect a substantially lower initial training status of arm—compared to leg—muscles. This is especially characteristic of relatively low trained subjects (Pogliaghi 2006).
Another training method during an injury is mental imagery. Many dismiss mental imagery, but mental imagery is thought to activate similar cortical regions as actually performing the task. This doesn't suggest mental imagery can train a swimmer to the Olympics, but it can be an adjust to rehabilitative training. Moreover, dynamic mental imagery appears to result in greater athletic performance (Guillot 2013). 

Practical Implications
If you injury your knee or your shoulder, continue training without pain! Find a way to continue swimming without aggravating the injured body part and you can still have success and enjoyment in the sport throughout the rehabilitation process. Whether you are kicking during a shoulder injury or performing dynamic mental imagery, no swimmer should sit on the side, as improvements are always possible!

  1. Lewis S, Thompson P, Areskog NH, et al. Transfer effect of endurance training to exercise with untrained limbs. Eur J ApplPhysiol. 1980;44:25–34.98.
  2. Pogliaghi S, Terziotti P, Cevese A, et al. Adaptations to endurance training in the healthy elderly: arm cranking versu sleg cycling. Eur J Appl Physiol. 2006;97:723–31.99.
  3. Issurin VB.Training Transfer: Scientific Background and Insights for Practical Application. Sports Med. 2013 Apr 30. [Epub ahead of print]
  4. Bhambani YN, Eriksson P, Gomes PS. Transfer effects of endurance training with the arms and legs. Med Sci SportsExerc. 1991;23:1035–41.100.
  5. Loftin B, Boileau A, Massey BJ, et al. Effect of arm training on central and peripheral circulatory function. Med Sci SportsExerc. 1988;20:136–41.101.
  6. Tordi N, Belli A, Mougin F, et al. Specific and transfer effects induced by arm and leg training. Int J Sports Med. 2001;22:517–24.102.
  7. Roesler K, Hoppeler H, Conley KE, et al. Transfer effect in endurance exercise: adaptations in trained and untrained muscles.Eur J Appl Physiol. 1985;1985(54):355–62.103.
  8. Magel JR, Mcardel WD, Michael T, et al. Metabolic and cardiovascula radjustment to arm training. J Appl Physiol. 1978;45:75–9.
  9. Guillot A, Moschberger K, Collet C. Coupling movement with imagery as a new perspective for motor imagery practice. Behav Brain Funct. 2013 Feb 20;9:8. doi: 10.1186/1744-9081-9-8
By Dr. G. John Mullen received his Doctorate in Physical Therapy from the University of Southern California and a Bachelor of Science of Health from Purdue University. He is the founder of Mullen Physical Therapy, the Center of Optimal Restoration, head strength coach at Santa Clara Swim Club, creator of the Swimmer's Shoulder System, and chief editor of the Swimming Science Research Review.

Swimming Science Podcast Episode 1: Dr. Shawn Sorenson Discusses Life After Sport and Training Lifetime Champions (TLC)

Ladies and gentlemen, welcome to the first episode of the Swimming Science Podcast. In this inaugural episode Dr. Sorenson discusses life after sport and the importance of developing well-rounded athletes for success in life. 

As you will see, the audio feed is not ideal, as this is a learning process for us at Swimming Science, if you have any feedback and/or suggestions, don't hesitate to post them in the comments. Lastly, if you are handy with iTunes or simply want to build the podcast, e-mail us today.

Shawn C. Sorenson, Ph.D. is an expert on lifetime health and well-being in elite athletes. He is an adjunct assistant professor at the University of Southern California, and creator of the Training Lifetime Champions (TLC) athlete health & wellness program. Dr. Sorenson offers health assessments, scientific guidance, and educational programs to corporate, youth, intercollegiate, and professional sports clients.

Click here to learn more about Dr. Sorenson and TLC

To download the episode, right click the play button.

Should Coaches Change Asymmetries in Swimmers?

If we set out to engineer the ideal swimmer, he/she would likely be 6’ 6’’ tall, have a massive wingspan, giant hands, froglike feet, and have a perfectly symmetrical body. Yet in reality, we know that many legendary swimmers have visually asymmetrical strokes, almost with one arm fly drill during freestyle.  Asymmetry is less pronounced in other strokes, but if you look close enough, the right and left sides are rarely identical.

Sanders (2011) offered a thorough review identifying causes of asymmetry such as brain laterality, handedness, genetics, previous injury, other sport participation, stroke technique, and fatigue.  Some causes are obvious (dominant hand for the non-ambidextrous); while others such as prior sport participation are less frequently mentioned.  The role of prior injury is yet another reason why care should be taken to resolve injuries before the brain grooves compensations to protect itself from further damage. 

Understanding the possible cause of a swimmer’s asymmetry is crucial to decide if or how to intervene.  We likely can’t change someone’s dominant hand nor can we use a time machine undo a prior sports history, but we can control stroke technique, fatigue, and retrain poor movement habits learned during injury.    Despite the appeal of a visually pleasing stroke, there are no style points in swimming (synchro and diving notwithstanding…).  Yet throughout the literature, asymmetry has been noted as a consistent predictor of injury.  It’s clear that few if any humans are perfectly symmetrical, but at some point asymmetry can become problematic in swimmers, even in short axis strokes.

The challenge for coaches is twofold: 1) does improved symmetry improve performance? 2) if it does, should asymmetries be corrected?  We can’t answer those questions definitively here, but we can try to bring science to an area that’s more commonly artful guesswork.   

Seifert (2005) studied both elite and recreational swimmers and noted that both groups demonstrated some degree of stroke asymmetry in a 100m trial.  However, authors noted that “more than the breathing laterality itself, the breathing actions of the non-expert swimmers amplified their asymmetric coordination on the breathing side. Conversely, the elite swimmers…managed their race better than the less proficient swimmers and their asymmetric arm coordination was not disturbed by breathing actions.”  This conclusion would suggest that fatigue plays as much a role in asymmetry than biomechanics.  Better swimmers keep the head more neutral during breathing; and poor breathing mechanics may feed asymmetry in the stroke. 

Tourney-Collett (2009) from the same lab as Seifert (2005) noted that asymmetrical breathing demonstrated a stronger correlation to asymmetric force production in sprinters than in middle distance and above.  Even though sprinters breathe less frequently than middle distance and distance, the left vs. right relationship is more skewed due to the higher overall force produced in sprinting.  However, in the long term, distance swimmers may accumulate more strokes with their asymmetrical patterns.  Sanders (2012) points out many different ways to measure symmetry, each of which have their own purpose.  What is most important to have some standard, and not assume that because something looks asymmetrical visually that it is thereby significant. 

In addition to the stroke, there are any other naturally asymmetrical movements in the water…we all push off the wall to a favored side to begin a set; favor one side to rotate on turns; we have a preferred side for the first stroke off each wall.  One possible strategy is to encourage use of your “off” side during warmups, but others may suggest such variation is too confusing both physically and mentally. 

Although not specific to swimming, there is literature to indicate asymmetry can be changed.  For example, Filipa (2010) showed that neuromuscular training could improve performance on the star balance excursion test, a test whose grade is based in part on symmetrical movement patterns.  This is just one example and it isn’t swimming, but it does show that with the right interventions better symmetry is possible.       

Asymmetry on dryland is a more straightforward analysis than in the water.  In general, significant asymmetries should be improved unless there is a specific reason to preserve status quo.  Making stroke changes is trickier, but will often depend on the cause of the asymmetry.  Coaches and swimmers must look beyond the visual presentation and consider all factors such as heredity, prior injury, stroke mechanics, and where the swimmer is in their career. 


  1. Filipa AByrnes RPaterno MVMyer GDHewett TE.  Neuromuscular training improves performance on the star excursion balance test in young female athletes.  J Orthop Sports Phys Ther. 2010 Sep;40(9):551-8. doi: 10.2519/jospt.2010.3325.
  2. Seifert LChollet DAllard P.   Arm coordination symmetry and breathing effect in front crawl.  Hum Mov Sci. 2005 Apr;24(2):234-56.
  3. Tourny-Chollet CSeifert LChollet D.  Effect of force symmetry on coordination in crawl.  Int J Sports Med. 2009 Mar;30(3):182-7. doi: 10.1055/s-0028-1104581. Epub 2009 Feb 12.
  4. Sanders, R, Thow, J, Fairweather M.  Asymmetries in Swimming Where Do They Come from?  J. Swimming Research, Vol. 18 (2011)
  5. Sanders, R, Thow, J, Alcock, A, Fairweather, M, Riach, I, Mather, F.  How can Asymmetries in Swimming be Identified and Measured? J Swimming Research, Vol 19:1 (2012)
By Allan Phillips. Allan and his wife Katherine are heavily involved in the strength and conditioning community, for more information refer to Pike Athletics.

Recovering from Injury: The Mental Side

Injuries are an inevitable part of competitive swimming no matter how robust our prevention and rehabilitation programs. We often discuss the mechanics of injury prevention and rehabilitation, but the psychological is also important.  Though many coaches prefer to wear the tough, authoritarian hat on deck, the softer side of dealing with injured athletes is an important skillset to have.  Nonetheless, athlete responses to injury can vary widely, from swimmers who won’t miss practice with a broken arm to others who beg out of practice with a paper cut.

Injury is not only a stress to body but also to the mind.  Evans (2012) noted that in addition to the physical stressors that cause injury, social and financial stressors will accompany any athletic setback.  With many swimmers spending more waking hours at the pool than anywhere else, their aquatic existence becomes part of their identity.  An injury robs them of that identity, which can be particularly troublesome for youngsters at socially vulnerable ages.  Finances can be equally stressful, with college scholarships and professional sponsorship potentially jeopardized.  Parents may add to frustration with pressure to validate a substantial investment into a swimming career.

Though direct causation is not certain, injury may also be tied with preexisiting psychological stress, There’s reason to believe that psychological factors may increase injury risk, but its still unclear what the exact mechanisms are. What is certain is that 
“psychological factors may also either hinder or facilitate rehabilitation adherence, compliance, and recovery.  Psychological distress may persist even after physical recovery has been completed.” Roh (2000). 

Doing all the right exercises important but is not enough; having the right attitude and an support network will increase a swimmer’s odds of a favorable rehab outcome.    

Podlog (2012) surveyed eight elite coaches in the Western Australian Institute of Sport and determined five crucial areas for coaches in the rehab process:

(a) coordination of a "team approach" to rehabilitation
(b) fostering open communication with athletes and treatment team members
(c) social support
(d) positive thinking and goal setting
(e) role models

These are all common sense areas but are often overlooked.  Communication is especially important and is a uniform theme in all of these recommendations.  Clement (2012) studied 49 injured athletes in D-II and D-III programs and found that social support from their ATC’s (athletic trainers) provided contributed significantly to overall well-being, as measured by eight types of support in a validated Social Support Survey.  Likewise, Judge (2012) studied 165 D-I athletes from six universities showed that strength and conditioning professionals had “significant psychosocial impact on student-athletes' overall psychological well-being during reconditioning.”   

Strategies like specialized kick and drill sets (rather than “go kick around for 30 minutes”) can keep an injured swimmers mentally engaged when they are in the water.  It’s also important to not marginalize athletes from the team during injury even if they aren't completing normal practice.  During rehab exercises, set goals (no matter how small) and remind athletes that many swimmers before them have successfully returned to training and competition.  Most importantly, keep the lines of communication open during what can be a highly stressful period, especially for a young athlete inexperienced with setbacks.    

1) Roh JLPerna FM.  Psychology/Counseling: a universal competency in athletic training.  J Athl Train. 2000 Oct;35(4):458-65.
2) Evans LWadey RHanton SMitchell I.  Stressors experienced by injured athletes.  J Sports Sci. 2012 May;30(9):917-27. doi: 10.1080/02640414.2012.682078. Epub 2012 May 3.
3) Podlog LDionigi R.  Coach strategies for addressing psychosocial challenges during the return to sport from injury.  J Sports Sci. 2010 Sep;28(11):1197-208. doi: 10.1080/02640414.2010.487873.
4) Judge LWBellar DBlom LCLee DHarris BTurk MMcAtee GJohnson J.  Perceived social support from strength and conditioning coaches among injured student athletes.  J Strength Cond Res. 2012 Apr;26(4):1154-61. doi: 10.1519/JSC.0b013e31822e008b.
5) Clement DShannon VR.  Injured athletes' perceptions about social support.  J Sport Rehabil. 2011 Nov;20(4):457-70.

By Allan Phillips. Allan and his wife Katherine are heavily involved in the strength and conditioning community, for more information refer to Pike Athletics.

Shoulder Moment Arms

While moment arm lengths may appear at first a very dry subject, there is a great deal we can learn from studying them. Some muscles have longer moment arms in a given plane than others, which tells us that they are more effective for certain actions. What’s more, muscle moment arms are different at various points in the joint range of motion, which tells us which muscles are most likely to be the prime movers when the joints are flexed, extended or in mid-range.

This study looks at the various moment arm lengths of the shoulder muscles and shows which are the largest in the main shoulder movements of abduction, adduction, flexion and extension, as well as the points in the ranges of motion where they are maximal.

The study

Moment arms of the muscles crossing the anatomical shoulder, by Ackland, Pak, Richardson and Pandy, in Journal of Anatomy, 2008

The background

The effect of a muscular contraction is to produce a turning force, or “torque” about a joint. Torque is equal to the muscular force multiplied by the moment arm, where the moment arm is the perpendicular distance between the joint and the muscle’s line of force. The moment arm of a muscle is an indication of its leverage at the joint in question. 

When a muscle has a long moment arm, it is usually capable of producing a large torque about the joint. Large muscles like the glutes and hamstrings, which are involved in powerful actions such as jumping and sprinting, tend to have long moment arms to help them increase their ability to generate torque. 

However, moment arms change depending on the joint angle. So a muscle might have a large moment arm when the joint is flexed but a much smaller moment arm when the joint is extended or vice-versa. By comparing the moment arms of various synergists at a joint, we can assess which muscle might be most important at different joint ranges of motion.

More generally, if we look at the maximum moment arm length that a muscle has across the whole range of motion at a joint, we can broadly assess the relative importance of the synergists at a given joint. But we need to be careful and recall that torque is a product of moment arm length and perpendicular muscle force production. What that means is that a large, highly activated muscle with an advantageous line of pull can produce much more perpendicular force than a smaller, poorly activated muscle with a poor line of pull. Nevertheless, the moment arm explains half of the torque-producing value, so it is still of great importance. 

What did the researchers do?

The researchers wanted to measure the moment arms of 18 different muscles and muscular sub-divisions in and around the shoulder. They decided to use the tendon excursion method to calculate these while the shoulder was (1) abducted and adducted (in the frontal plane), and (2) flexed and extended (in the sagittal plane). They wanted to see which muscles had the largest moment arms and were therefore most useful for abduction, adduction, flexion and extension.

To measure the moment arms, the researchers obtained 8 fresh-frozen, entire arms from human cadavers (4 male and 4 female) from elderly, deceased subjects who had displayed no sign of any osteoarthritis or other degeneration of the muscles or skeleton. They attached the arms to a piece of apparatus for abducting, adducting, flexing or extending the shoulder while the muscles at the shoulder joint were pinned and the tendon excursions as a result of the muscle actions measured.

What happened?

The researchers found that the most effective shoulder muscles were as follows:

  • Abductors – middle and anterior deltoids
  • Adductors – teres major, middle and inferior latissimus dorsi, and middle and inferior pectoralis major
  • Flexors – superior pectoralis major, anterior and posterior supraspinatus and anterior deltoid
  • Extensors – teres major and posterior deltoid

The following graph shows the maximum moment arms in abduction (positive) and adduction (negative) for each of the shoulder muscles measured:

The following graph shows the maximum moment arms in flexion (positive) and extension (negative) for each of the shoulder muscles measured:

The researchers also measured at what range of motion the moment arms of the shoulder muscles were maximal in abduction and adduction. They found that for the main abductors, the anterior deltoid moment arm was maximal at full abduction (120 degrees) while the middle deltoid moment arm was maximal at 80 degrees, just below the horizontal. For the other significant abductors (i.e. posterior and anterior supraspinatus), it is interesting to note that they all had maximal moment arms at very low degrees of abduction (i.e. < 10 degrees).

The researchers found that for the main adductors, the teres major, middle and inferior latissimus dorsi, and middle and inferior pectoralis major, the moment arm lengths were all maximal between 40 – 80 degrees of abduction. The teres major was maximal at the greatest degree of abduction and the pectoralis muscles were maximal at the smallest degrees of abduction, with the latissmus muscles in between. The following graph shows the ranges of motion at which the muscles had their greatest moment arms.
The researchers also measured at what degree of flexion the moment arms of the shoulder muscles were maximal in flexion and extension. They found that for the main flexors, the superior pectoralis major, anterior and posterior supraspinatus and anterior deltoid, there were large differences in respect of where each of the muscles had their maximum moment arm lengths. The anterior and posterior supraspinatus were maximal at < 5 degrees of flexion. The superior pectoralis major was maximal at 70 degrees and the anterior deltoid was maximal at 120 degrees.

In respect of the main extensors, the teres major and posterior deltoid, the researchers found that the teres major had its maximal moment arm at 56 degrees of flexion and the posterior deltoid at 30 degrees. For the less effective extensors, the researchers noted that the superior latissimus had its maximum moment arm length at 65 degrees of flexion and the teres minor at < 5 degrees.

What else did the researchers observe?

The researchers also noted some features of various key muscles, as follows:

  • Latissimus dorsi – the researchers observed that the moment arm lengths of the three regions of the latissimus dorsi followed a distinctly parabolic path and were minimal at small and large joint ranges of motion but maximal in mid-ranges. They also noted that the maximum moment arms during mid-abduction were greater in the middle and inferior sub-divisions of the latissimus than in the superior sub-division. They noted that the reverse was the case during mid-flexion.
  • Supraspinatus – they noted that the supraspinatus was more effective as a shoulder flexor than as a shoulder abductor and that their peak moment arms for flexion were greater than that of the middle deltoid.

What did the researchers conclude?

The researchers concluded that the supraspinatus appears to be heavily involved in early phase shoulder abduction while the deltoid muscles seem to be more involved as prime movers in mid-to-late abduction. This supports the findings of previous research.
The researchers also concluded that the middle and anterior deltoids had the greatest moment arm lengths for abduction, while the superior pectoralis major, anterior and posterior supraspinatus and anterior deltoid had the most effective moment arms in flexion. However, they also concluded that the anterior and posterior supraspinatus muscles had greater moment arm lengths than the anterior deltoid in flexion.

The researchers explain that these findings have important implications for which movements and ranges of motion athletes are likely to find troublesome after full-thickness rotator cuff tears.

What were the limitations?

The researchers commented that their study was limited in that by using the tendon excursion technique it is difficult to control and eliminate humeral internal and external rotation and glenohumeral joint translation. This may have led to errors in some of the measurements.

What are the key points?

This study provides a great deal of food for thought, with the following three key points for swimmers coming out of it:

  • The most effective shoulder abductors in terms of moment arm lengths are the middle and anterior deltoids, followed by the anterior and posterior supraspinatus. The deltoid muscles are the prime movers in mid-to-late abduction, while the supraspinatus is heavily involved in early phase shoulder abduction. This may imply that this rotator cuff muscle could easily be stressed by repetitive muscular actions involving low degrees of shoulder abduction, such as the initial part of the recovery phase in freestyle.
  • The most effective shoulder extensors in terms of moment arm lengths are the teres major and posterior deltoid, followed by the superior latissimus and teres minor. These muscles are particularly important for the freestyle and fly strokes. While most people will recognize the latissimus as the “swimming muscle,” it is important to realize that there are other extensors with more effective moment arms. While these muscles are clearly trained using standard shoulder extension exercises such as pull-ups, chins and rows, they can also be targeted using more specific exercises in the case of the posterior deltoids, such as the rear delt fly.
  • The shoulder extensors are all most effective in the middle of the movement. This may suggest that training the shoulder extensors at end ranges, perhaps using bands or chains, may be helpful for both smooth delivery of power and for injury prevention during swimming.

By Chris Beardsley a biomechanics researcher and author of a book about scientific posterior chain training. He also writes a monthly review of the latest fitness research for strength and sports coaches, personal trainers, and athletes.

Resolution of Pain is Not the End Game!

In any sport, injuries come and they go. This is the nature of placing high levels of stress on your body. Swimming places the most stress on the shoulders and low back, both frequent sites of pain in swimmers. If you search swim decks, you'll find a plethora of swimmers with a long history of low back or shoulder injuries. Most of the time, these symptoms are in remission and all is perceived as fine. However, resolution of pain is not the end game! In fact, after any injury (no matter the severity) current research is demonstrating a residual effect of muscle coordination. Unlike popular belief, this dysfunctional muscle timing during the injury does not resolve once pain is resolved. Also, the literature suggests previous injury is universally recognized as one of the most predictive factors of future injury.

This phenomenon has been demonstrated most recently in a study by Butler (2012) in the low back, but as rehabilitation specialist, I can assure you this occurs at all joints. Just think of the last time you hurt yourself, for example if you stubbed your toe on the way to get a drink at night (read about the importance of hydration on cognitive-motor skills). When you stub your toe, you likely scream a few obscenities (this may also improve the pain), then you hobble around the house like Frankenstein until the pain resolves. This hobbling is altering your normal motor control to mitigate the pain in your toe. Now, if this pain resolves and you return to normal walking in a few minutes, then the amount of time spent altering this motor control is minimal, a little harm is done. However, most injuries don't last a few days, as they frequently last days, weeks, years, or even decades. This extended alteration in motor control is damaging and likely causing the results in Butler's study when she compared a few movements in those in remission of low back pain compared to those without low back pain. In fact, the low back pain remission group had higher muscle activation during the activity. However, the posterior fibers of the external oblique had decreased activation. This altered motor programming leads to some muscles being over active and some being under active. Moreover, this leads to stroke compensations which are repeated thousands of times every day, even if not perceptible to the naked eye; all of which leads to risk of reinjury or at least can impair performance if the swimmer is subconsciously using excess tension to maintain normal biomechanics. For a full resolution of an injury, improvement in symptoms, imbalances (muscle length and strength), and motor control (muscle timing) are key! Unless you improve all these facets, your injury is likely to return. In swimming, if you have a history of shoulder injury, you're at a higher risk of reoccurrence, unless the proper precautions and rehabilitation is received. Make sure you seek and demand full improvement of the injury, not simply resolution of pain, as this is far from the end game!

Do not be content with the resolution of pain. Seek further improvement of the injury and improve the underlying issues of muscle length, strength, and timing. For the shoulder, consider purchasing the Swimmer’s Shoulder System.

  1. Butler HL, Hubley-Kozey CL, Kozey JW. Changes in electromyographic activity of trunk muscles within the sub-acute phase for individuals deemed recovered from a low back injury. J Electromyogr Kinesiol. 2012 Nov 28. doi:pii: S1050-6411(12)00195-2. 10.1016/j.jelekin.2012.10.012. [Epub ahead of print]
By G. John Mullen founder of the Center of Optimal Restoration, head strength coach at Santa Clara Swim Club, creator of the Swimmer's Shoulder System, and chief editor of the Swimming Science Research Review.

Inflammation in Sports

Inflammation in sports is a baffling subject. Some view inflammation as beneficial, while others consider it detrimental. This subject is confusing as inflammation occurs in seemingly two different scenarios. For example, how can inflammation after exercise be beneficial, where inflammation about injury is harmful if both are the same process?

This article tackles the difference between inflammation after injury and exercise while providing a practice approach for using common anti-inflammatory medication.

Spotting Inflammation
There are five attributes to inflammation in sports:
  • Redness, swelling, heat, pain, loss of function
Moreover, pain all the time (not only during movement) and pain in the morning are typical signs of inflammation. Increased joint fluid increases pressure on pain receptors (nocioceptors), causing pain all the time. If pain is worse in the morning, it is likely inflammation surrounds the joint, as muscle contractions did not pump the fluid away from the joint during sleep. This increased fluid increases the pressure on pain receptors increasing pain during the morning.

Exercise Induced Inflammation
Many feel inflammation in sports help long-term strength gains as inflammation repairs damaged muscle fibers following exertion. Mishra in 1995, determined supplementing a strength training group with anti-inflammatory medication had an acute increase in strength, compared to the control group. This increase persisted at 7 days, but at 28 days the medication group experienced a step back, as their maximal muscle tension dropped by about 1/3 of their maximum tension.

It appears anti-inflammatory medication resolves acute exercise induced inflammation resulting in increased strength, as it would allow them to recover and be stronger, as they less sore from the muscle fibers being destructed during the exercise.

However, the mechanism which NSAIDs improve acute performance has not been justified:
“anti-inflammatory doses of ibuprofen reduced CK activity but not the neutrophil response or other indirect markers of muscle injury during recovery from eccentric arm exercise (Pizza 1999).”

After training Gulick performed an analysis of many types of treatment and concluded:

“none of the treatments were effective in abating the signs and symptoms of DOMS. In fact, the NSAID and A. montana treatments appeared to impede recovery of muscle function (Gulick 1996).”

Therefore, it seems NSAIDs improve acute strength with NSAID, but it seems to prevent overall recovery of muscle and strength gains.

This is perhaps from NSAIDs masking the amount of damage during exercise, allowing the body to do more damage without allowing proper recovery time. Don't beat yourself while you're down!

No study has directly studied NSAIDs on in-water strength, but one could guess NSAIDs would impair in-water strength development. This loss of strength impairs swimming progress as in water strength (especially of the upper body) correlates with speed (Hsu 2000).

Injury Induced Inflammation
After any musculoskeletal injury inflammation occurs. This process increases the volume of fluid in an unwanted area. When too much fluid is in a confined area, the amount of mechanical pressure increases. This mechanical pressure presses on nocioceptors and causes pain. Pain inhibits strength and athletic performance, therefore resolving this mechanical pressure is mandatory to move the injury from inflammation to remodeling.

The best method to improve this is with homeopathic and over-the counter medication. Combining Ginsenosides and Large volumes of NSAIDs helps inflammation by helping the medication reach 'titer level' or the minimum effective level (Read more about tips to improve shoulder inflammation) (note: take with food and watch stomach irritation).
Once the inflammation subsides, discontinuing the anti-inflammatories is essential for improving strength (see below).

If you are looking for short-term improvement whether you are at a competition or injured, NSAIDs acutely improve strength. However, if you’re seeking long-term strength gains, do not use NSAIDs to trick the body into working harder or not letting inflammation to aide full repair and remodeling, essentials for muscle strength.

Last Point
Lastly, the chronic use NSAIDs appears damaging to tendons.

In rats, Dimmen 2009 determined:
“We found a significantly lower tensile strength in rats given both parecoxib and indomethacin (anti-inflammatory medications) compared to the control group. Stiffness in the healing tendons was significantly lower in the parecoxib group compared to both the placebo and the indomethacin groups. The transverse and sagittal diameters of the tendons were reduced in both the parecoxib and indomethacin groups. Both parecoxib and indomethacin impaired tendon healing; the negative effect was most pronounced with parecoxib (Dimmen 2009).”

This has not been proven in humans, but is worrisome nonetheless.
Make sure you are not abusing NSAIDs and use them properly, as overuse is damaging and reckless. Follow these simple guidelines:
  • Only take NSAIDs after an acute musculoskeletal injury
  • Discontinue intake after inflammation resolves
  • Do not take NSAIDs after exercise unless at a competition, where performance not strength gains are most important
  1. Pizza FX, Cavender D, Stockard A, Baylies H, Beighle A. Anti-inflammatory doses of ibuprofen: effect on neutrophils and exercise-induced muscle injury. Int J Sports Med. 1999 Feb;20(2):98-102.
  2. Gulick DT, Kimura IF, Sitler M, Paolone A, Kelly JD. Various treatment techniques on signs and symptoms of delayed onset muscle soreness. J Athl Train. 1996 Apr;31(2):145-52.
  3. Dimmen S, Engebretsen L, Nordsletten L, Madsen JE. Negative effects of parecoxib and indomethacin on tendon healing: an experimental study in rats. Knee Surg Sports Traumatol Arthrosc. 2009 Jul;17(7):835-9. Epub 2009 Mar 19.
  4. Hsu, K. M., & Tsu, T. G. The relationships among shoulder isokinetic strength, swimming speed, and propulsive power in front crawl swimming. Medicine and Science in Sports and Exercise. 2000 32(5).
  5. Defreitas JM, Beck TW, Stock MS, Dillon MA, Kasishke PR 2nd.An examination of the time course of training-induced skeletal muscle hypertrophy. Eur J Appl Physiol. 2011 Mar 16.
By G. John Mullen founder of the Center of Optimal Restoration, head strength coach at Santa Clara Swim Club, creator of the Swimmer's Shoulder System, and chief editor of the Swimming Science Research Review.