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RER Value Guide

Slow (0.7)
A1 band - warm-up, recovery, cool-down sets
Moderate (0.85)
A2 band - aerobic capacity sets
Intense (1.00)
A3 band - aerobic power, VO2max sets

Data Source: Zamparo P, Bonifazi M (2013). Bioenergetics of cycling sports activities in water.

Coded for Swimming Science by Cameron Yick

Freestyle data

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Nathan Adrian vs James Magnussen Performance Predictions from 2013 World Championships

The men 100m free is the main race in any major competition, such as Olympic Games and World Championships. Everybody talks about that race long before the competition kicks off, including media that dedicates a lot of articles about it. Who will get a seed at the final, who are the main contenders, what will be their main strategies and so on. But the media aren't the only people chatting, as swimming fans often do the same, and me and my friends are no exception. Right after the semi-finals, the day before the final, we were chatting about all this and I came out with the idea of profiling the two main contenders (at least in our view and most of the media): James Magnussen (Australia) and Nathan Adrian (US).

Let’s start with some background about sports performance profiling. A profile is a collection of features that might characterize someone. Sports performance profiling can include anthropometrical, biomechanical, physiological, psychological variables besides others. It should be stressed that rather than predict the performance, profiling aims to help athletes get awareness of their strongest and weakest points, as well as, from their main competitors. So, we can use this technique to identify the main race strategies of a swimmer.

Hence, my idea was to carry out an analysis of James Magnussen and Nathan Adrian based on their performances between 2012 Olympic Games (London) and 2013 World Championships (Barcelona) semi-final and then see if that matched with the race on the following day (i.e. the final).

Races times between 2012 OG and 2013 WC semi-finals (i.e. on July 31th) were retrieved from a database (www.swimrankings.net). Relay races were only considered if the swimmers lead off the relay. Reaction time, first lap split time, second lap split time and final time were compared. This analysis included sixteen races for Nathan Adrian and thirteen for James Magnussen.

Two profiling techniques were selected. The ones reported by James et al. (2005) and by O’Donoghue (2005). James et al. (2005) technique represents performance as a collection of all variables, determines the median and the 95% confidence interval for the median for each outcome. O’Donoghue (2005) technique produces a profiling based on quantiles. This is done calculating the quantiles for each variable selected and plotting it on a radar chart.

According to data collected, Nathan Adrian is the fastest on the block and the first split but James Magnussen is quicker during the second lap and might win the race (table 1). Nathan Adrian performances seem to be more consistent than the ones from Magnussen (table 1 and figure 1). The perception, from a qualitative point of view is that the upper limits of the 95% CI are little bit too high. The explanation to this has to be related to the fact that during prelims in major competitions and even races at the beginning of the season, strategies might be different from the ones in the final.

Table 1. Performance profile for the two main contenders of the 100 m free final at the 2013 World Championships (Barcelona).

Our profiling was put to the test on Aug 1st, as the two squared off. Results were as follows:

James Magnussen (reaction time: +0.68s; 1st split: 22.80s; 2nd split: 24.91s; final time:47.71s);

Nathan Adrian (reaction time: +0.64s; 1st split: 22.38s; 2nd split: 25.46s; final time: 47.84s);

So, actually Nathan Adrian was the fastest on the block and in the first lap, while James Magnussen was quicker during the second lap and won the race. Most results are within the 95% CI, even though some prelim and earlier races in the season turn out those limits a little bit too wider than expected. This could be solved removing those races (but would decrease even more the small dataset obtained) or inserting a correction factor to fine-tune the profiles (e.g. importance of the competition).

However as we learned on that same day, Nathan Adrian was third while James Feigen (USA) was second (reaction time: +0.69s; 1st split: 22.91s; 2nd split: 24.91s; final time: 47.82s). These same techniques could be used to profile all finalists and if possible identify an outsider, an underdog. Eventually this should be done complementing the profile obtained with some tracking techniques, such as the ones reported by Bragada et al. (2010) in middle-distance running.

A few limitations must be addressed: (i) strategies might be different from race to race (i.e. beginning of the season vs. main competition; prelim vs. final, etc.); (ii) there are more accurate techniques (e.g., considering the effect of different type of competitions, quality or ranking of the performers involved) which might fine-tune the profile obtained; (iii) not all finalists were profiled, being this techniques most convenient and useful to identify and characterize underdogs rather than the favorites or top dogs, as the last ones are very well-known; (v) overall, a higher dataset and more time to carry out the analysis would increase the accuracy of the profiles obtained.


  1. Bragada JA, Santos P, Maia JA, Colaço P, Lopes VP, Barbosa TM (2010). Longitudinal study in 3000m male runners: relationship between performance and physiological parameters. Journal Sport Science & Medicine. 9: 439-444
  2. James N, Mellalieu SD, Jones NMP (2005). The development of position specific performance indicators in professional rugby union. Journal Sport Sciences. 23: 63-67
  3. O’Donoghue PG (2005). Normative profiles of sports performance. International Journal Performance Analysis Sports. 5: 104-109.
Tiago M. Barbosa earned a PhD degree in Sport Sciences and holds a position at the Nanyang Technological University, Singapore

Friday Interview: Dr. Shige Kudo Discusses Hand Acceleration

1. Please introduce yourself to the readers (how you started in the profession, education, credentials, experience, etc.).
I started studying swimming Biomechanics in Japan under master program at Mie Univeristy and continued studying it under PhD program at University of Otago, New Zealand. Through the degree programs, I investigated hydrodynamic forces acting on the hand in swimming and developed the new method to predict hydrodynamic force on the hand (dynamic pressure approach) and quantified acceleration effect on hydrodynamic force on the hand in swimming using a hand model. Republic Polytechnic, Singapore, has provided me further opportunities to apply the findings based on the hand model testing to the swimmer’s hand. We have been using the dynamic pressure approach to predict propulsive hand force exerted by the hand and support swimmers to improve their performance.

2. You recently published an article on the effect of unsteady flow due to acceleration on hydrodynamic forces, could you briefly explain the importance of understanding the influence of acceleration for swimmers?
Hand velocity was initially discussed to improve the performance in terms of the exertion of hand propulsion. This is because the methodology of the quantification of hydrodynamic forces acting on the hand (quasi-static approach) was developed in 1970s and popular to use to evaluate hand propulsion during swimming in 1980s. The quasi-static approach assumed that the swimmer’s hand moves at constant speed during swimming. Several studies highlighted that the assumption was not valid and hand acceleration should be taken into account. Hand acceleration results in the different flow condition (unsteady flow) around the hand, which involves larger size of vortices around the hand. Also when the hand accelerates, the hand drags some volume of surrounding water (added mass). These vortices and added mass are to influence propulsion exerted by the hand during swimming. Our work showed that hydrodynamic forces on the accelerating hand could be much greater than the forces on the non-accelerating object. A previous study using computational fluid dynamics (CFD) also showed the similar result. A swimmer accelerates the hand at the beginning of insweep motion during the frontal crawl stroke. Thus, it is possible that a swimmer exerts a great amount of propulsion at the beginning of insweep phase.

3. Can you please describe your methods and how you constructed your model? Also, what are the main differences between your model and humans?
The hand model was made of silicon base material. The hand model was rotated in the flowing swimming-flume and measured hydrodynamic forces acting on the hand part only while the entire model consisted of the hand and forearm. The velocity and acceleration of the hand model were approximated to the ones attained by a swimmer. The main difference between our model and humans was that the model does not rotate about its longitudinal axis (axis parallel to the forearm) during the model rotation. A swimmer conducts the shoulder extension while doing supination/pronation during the stroke. During our measurement, we rotated the model about the transverse axis (shoulder extension) while the model was fixed about its longitudinal axis (no supination/pronation). Thus, the model movement is similar to the motion which a person rotates an arm about the shoulder axis while the palm of the hand is directed to backwards.

4. What were your main findings?
Our main findings were that 1) an accelerating hand in general motion can induce additional fluid forces acting on the hand compared to a non-accelerating hand and 2) hand deceleration can induce instantaneous additional fluid forces acting on the hand in general motion. As for the first finding, it has been known and quantified that an accelerating hand can induce the additional forces in linear and angular motions (moving straight and rotating about an axis, respectively) but this study shows the effect of acceleration on the hand in general motion (combination of linear and angular motions), which is similar to a swimming stroke. As for the second finding, deceleration was expected to reduce hydrodynamic force acting on the hand. But this study shows that a hand deceleration can induce additional force on the hand for a short period.

5. How can a swim coach use this information?
They may want to consider a drill in the hand stroke. A coach and swimmer should focus the hand acceleration at the beginning of the insweep phase because a swimmer is likely to start accelerating and sweeping the hand from the insweep phase.

6. What future research is necessary for confirming these results?
We need to investigate how an additional force on the hand due to hand acceleration is induced and how the force can be maximized during the swimming stroke by changing the hand orientation or the magnitude of hand acceleration. Those studies should support a swimmer and coach to improve the stroke technique.

7. Do you think this study confirms the biomechanics noted in elite swimmers or is there something elite swimmers should take away from this study? 
During the swimming stroke, hand acceleration can induce an additional hydrodynamic forces acting on the swimmer’s hand.

8. Does this study apply to all strokes?
Yes it can be applied. Hand orientation might be different from the work. But we measured hydrodynamic forces acting on the accelerating hand at the different hand orientation in our other works and we observed an additional hydrodynamic forces acting on the accelerating hand.

9. Many swim coaches support "anchoring" the arm during the catch, does this study confirm or dispute this coaching?
This study may not relate to the concept of “anchoring” the arm during the catch. I believe that anchoring the arm during the catch is to reach the position in order for the hand and forearm to move backwards as soon and further as possible. The moment just after the catch is important for a swimmer to accelerate the hand because this phase is one of critical phase when a swimmer can accelerate the hand. In my opinion, whether a swimmer conducts “anchoring” the arm during the catch or not, hand acceleration induces an additional force on the hand. And “anchoring” the arm during the catch may be beneficial in terms of having more duration to accelerate the hand.

. What research or projects are you currently working on or should we look from you in the future?
We are working on the development of system which can measure hand propulsion with a wearable and portable system. Also we are working on quantifying the effect of acceleration on the hand propulsion during actual swimming.


  1. Kudo S, Vennell R, Wilson B. The effect of unsteady flow due to acceleration on hydrodynamic forces acting on the hand in swimming. J Biomech. 2013 Jun 21;46(10):1697-704. doi: 10.1016/j.jbiomech.2013.04.002. Epub 2013 May 17.

Friday Interview: Mathias Samson Ph.D. Candidate Discusses the Entry Phase

1. Please introduce yourself to the readers (how you started in the profession, education, credentials, experience, etc.). I am a coach of swimming for 15 years, as well as a teacher who has passed aggregation of physical education. I coached in club during years, young people in particular, at the national level. Since 2007, I work on the University of Poitiers, and I handle the formation of students in swimming (theory and practice). I followed, besides, a university program in mechanics which was finalized by the obtaining of the diploma of Master's degree titled « Research and development in Mechanics » of the University of Poitiers. I pursue at present a Doctoral Thesis concerning the understanding of unsteady mechanisms engendered by the aquatic strokes of arms in crawl, in various paces of swimming.

2. You recently published an article the entry phase of freestyle, could you explain your findings? The realized works show that the entry-and-stretch phase has an important function in the global organization of the swimming, in particular when the pace of swimming varies. It has for function, not only to prepare the later phase, but also to manage the general balance of swimming. So it varies a according to the pace of swimming a lot, it is moreover one of the phases that varies most (in particular, in term of duration and trajectory). However, all the authors do not agree on its definition or on its function: is it propelling or not? When does it end? For my part, I lean on the definition of Maglischo (this phase begins when the hand entry into the water and finishes when the opposite arm finishes this action), because it allows to discuss the continuity of the propelling actions. Indeed the end of the entry-and-stretch phase is synchronized with the end of the propulsion of the opposite arm.

3. Based on the findings, what common misconceptions exist regarding the entry phase? A first idea, would be to think to think that this phase would serve to decrease the drag forces through the effect of bulbous bow: this is not strictly a misconception, but it would rather deserve to be tested: in hydrodynamics, a "bulbous bow" applies only in some very specific configurations (rapport length ration of the bulb and the boat, the sinking parameter, velocity of boat). Another one is to believe that this phase remains identical according to the pace, with a tense arm forwards: but it is doubtless the one which evolves most when the frequency of swimming varies. 

4. Do you think elite swimmers could do anything better during the entry phase? This phase has to allow to coordinate a number of actions (balance of body and breathing), and it is made at the same time as the important propulsive phases of the opposite arm (insweep and upsweep), also it does not especially have to create too many drag forces. However, it does not either have to be only a moment when the swimmer remains the tense arm forwards of by thinking that drag is decreased whereas the other arm propels. It is always a compromise between a time of glide and a propelling time: to slide too much, the performance can be impacted. So, it has to, as fast as possible, be capable to assure a propulsion the body, to aim at a continuity of the propelling actions of the arms. For this, the orientation of the arm does not have to be only forwards, but already, at the end, in rotation downward. However, it depends on the stroke frequency of the arms, but also anthropometric characteristics of the swimmers. For example, Chinese Sun Yang, Olympics champion to London in 2012, swam the 1500 NL in 14 ' 31 ", with a tense arm forwards during all the phase of propulsion of the opposite arm, but remains exceptional.

5. Many debate over if drag or lift are more important for swimming, what is your opinion? Effectively, the debate is engaged for thirty years, and in particular for the works of Counsilman. Lift forces, having been highlighted by Schleihauf in the seventies, have fundamentally changed the view of propulsion, and numbers of authors or coaches have adopted this point of view linked at a sinusoidal kinematics. Then we attended during these last years in a kind of step backward, during which authors have had tended to favor the importance of drag forces (cf. the “mea culpa” of Maglischo in particular, at the end of the nineties). But these views did they fundamentally changed the technique of swimmers, it is difficult to say? Researchers, conducted over the past 20 years, both in towing tank and by pressure sensors measurements, suggest the importance of the two components in contributing to propulsion, with perhaps a dominant drag during the insweep phase. But these studies should be continued. For my part, I note, and all kinematic studies agree on this, that aquatic arms trajectories are sinusoidals. In addition, most aquatic or aerial mammals propel themselves with sinusoidal trajectories to adapt themselves the most of the intrinsic characteristics of the environment (deformable and incompressible). So I think we still have much to understand about the swimmer propulsion mechanisms. Also, do not reduce this complexity to a simple lift or drag debate, anyway, these two forces exist. There is more to understand how these two components are formed, going beyond the theory of Bernoulli, which is now known is insufficient to explain the mechanisms of creation of these forces, because the flow is highly turbulent.

6. What are the common flaws during the entry phase? For a novice, the main flaw is not to make this entry-and-stretch phase (for begin directly the propulsive phase), what does not allow him to prepare the catch phase, but also not to balance himself during the breathing (this flaw is even more perceptible in butterfly). For the expert swimmer, the main flaw is to have an entry-to-stretch phase too long, what engenders a propulsive timeout too long, in particular in the sprint and middle-distance paces.

7. How can people improve this flaw? For the novices, it is necessary to learn to swim with the arms in opposition, by marking a stop-time during the learning of the side inspiration. For the experts, this flaw is difficult to correct, because this long entry-and-stretch phase often allows them to be very efficient in propulsion with the opposite arm. One of the means to improve it this is to work on the stroke frequency, at characteristic frequencies of the paces of race: 50-55 cycles per minute in sprint, 40-45 cyc/min in middle-distance, 35-40 cyc/min in distance pace.

8. What are your thoughts on "feel" or "motor control" during the entry phase? I think that both are important. The specificity of the aquatic environment, imposes on the swimmer, to feel the flow of the water around its body to interact there better. Besides, the swimmer is more isolated that other sportsmen when he trains, the external feedback are less numerous: he needs to have feel to build his technique. However, build the progress of the swimmer only on this feeling, it is to take the risk of a technique not adapted to the pace of race. The coach has to evaluate if the swimmer does not get lost too much in these feeling, in particular on the duration of the entre-and-stretch phase which must be very adapted to the races to be swum.

9. What research or projects are you currently working on or should we look from you in the future? I try to understand the flow engendered by the movements of the swimmers (in particular the arms), in the various paces. I think that the trajectory of arms have a certain coherence, quite as are it the flapping of the wings of birds or the fins of fishes. However, we are not conceived to evolve in the water, except our capacity of buoyancy maybe. The engendered flow, fundamentally turbulent and unsteady, is nevertheless, doubtless, constituted of coherent structures. These ones, engendered flows, which have to play a preponderant role in the swimmer propulsion. All the difficulty is to study these structures, which are invisible in the eye, quite as is it the flow around the wings of birds. To visualize and to understand these structures would doubtless allow to explain better, and why not to optimize, the techniques of the swimmers. It is the aim I set for myself, and for it, the PPrime Institute of the University of Poitiers has successful and modern search tools (PIV method, dynamometric balance, towing tank, CFD).

Coaches Don't Know Why Freestyle is the Fastest Stroke!

Freestyle is the fastest of the four strokes. Unfortunately, like many obvious statements, the reasoning for this statement goes undiscussed or debated. Yet, I'd argue many people involved in swimming can not argue with facts (not simply expert opinion) why freestyle is the fastest stroke. Sure, these coaches could be certified with as many swimming certifications as there are to hand out, but the fact of the matter remains, they can't define one of the most obvious statements in the sport: freestyle is the fastest of the four strokes!

When it comes to the fastest stroke many variables are involved and these variables carry different importance depending on the swimmer. However, the energy exerted, force production/intra-cycle velocity variation are large players in the equation.

If an athlete can go a specific speed while expending less energy, one could argue this makes the stroke more efficient and faster. Barbosa (2006) had elite swimmers swim their main stroke at varying speeds (1.0, 1.2, 1.4, and 1.6 m/s). Him and his colleagues found freestyle required significantly less energy than the other strokes at 1.6 m/s. Unfortunately, this study did not measure energy demands at maximal speed, nonetheless, this suggests freestyle is the most efficient stroke. 
Force Production
The more force produced during swimming, the more potential an athlete has for speed. Morouço (2011) had elite swimmers perform tethered swims while their force was measured. The higher maximal force in breast and fly were also associated with lower minimal values. It seems freestyle is likely the fastest stroke due to the continuity of force production. However, the researchers note some potential error, as when the tether goes to zero, there is a retensioning effect which spikes the force measurement. The mean force was an applicable measure for predicting success in 50-meter performance.

Producing force is great, but maintaining a steady force and velocity is more essential. Intra-cycle velocity variation measures the differences between the peaks and valleys of velocity during a stroke. Freestyle has been shown to have lower intra-cyclic velocity variation, implying lower energy expenditure, and higher mean propulsion propulsive (di Prampero 1986; Toussaint and Hollander 1994; Vilas-Boas et al., 2011).

Practical Implication
Knowing why freestyle is the fastest may seem unnecessary, but to truly understand something, being able to defend and justify it is key. Knowing exactly what makes a stroke fast is essential for understand how to make other strokes fast and how to go faster. Unfortunately, too many coaches aren't given the correct tools or resources to improve. Moreover, why freestyle is the fastest stroke may change as more research surmounts!

Don't be complacent with the answer, be hungry for the reasoning!

  1. Morouço P, Keskinen KL, Vilas-Boas JP, Fernandes RJ. Relationship between tethered forces and the four swimming techniques performance. J Appl Biomech. 2011 May;27(2):161-9.
  2. Barbosa TM, Fernandes R, Keskinen KL, Colaço P, Cardoso C, Silva J, Vilas-Boas JP.Evaluation of the energy expenditure in competitive swimming strokes. Int J Sports Med. 2006 Nov;27(11):894-9. Epub 2006 Apr 11.
  3. di Prampero PE.The energy cost of human locomotion on land and in water. Int J Sports Med. 1986 Apr;7(2):55-72. Review.
  4. Toussaint HM, Hollander AP.Energetics of competitive swimming. Implications for training programmes. Sports Med. 1994 Dec;18(6):384-405. Review.
  5. Sousa AC, Figueiredo P, Oliveira NL, Oliveira J, Silva AJ, Keskinen KL, Rodríguez FA, Machado LJ, Vilas-Boas JP, Fernandes RJ.VO2 kinetics in 200-m race-pace front crawl swimming.Int J Sports Med. 2011 Oct;32(10):765-70. doi: 10.1055/s-0031-1279772. Epub 2011 Sep 12. 
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.

Relaxing Until the Finish

As discussed a few days ago, the arms greatly contribute to force production in swimming (Finger Positions in Swimming). Unfortunately, many coaches and swimmers may use incorrect cues to finish their races, trying to "push harder" or "fight through the pain". Instead, certain studies suggest the importance of relaxing until the finish.

Electromyography (EMG) during swimming is not novel, as EMG and swimming studies date back to 1986 (Nuber 1986), but the practicality of these findings still hasn't been adapted. Figueiredo (2013) notes at the end of an exhaustive 200-m freestyle race, the EMG of the upper extremities increased (figure-1). These alterations in EMG likely cause the changes in kinematics in the upper extremity. In the lower extremities, the EMG was relatively stable, although a decrease in kick frequency did occur, likely to complement the change in stroke frequency. 


Practical Implication
Alterations in upper extremity EMG appear to be correlated with kinematic changes during an exhaustive 200 m freestyle. Swimming training should attempt to maintain the same swimming EMG throughout the whole race. This likely occurs if the swimmer is capable of relaxing throughout times of stress at the end of the race. Many relaxation methods and dissociative thinking methods exist for this purpose.

Currently, swimming EMG is common for coaches, but is likely an avenue for evaluation in the future.
  1. Figueiredo P, Sanders R, Gorski T, Vilas-Boas JP, Fernandes RJ. Kinematic and electromyographic changes during 200 m front crawl at race pace. Int J Sports Med. 2013 Jan;34(1):49-55. doi: 10.1055/s-0032-1321889. Epub 2012 Aug 17.
  2. Nuber GW, Jobe FW, Perry J, Moynes DR, Antonelli D. Fine wire electromyography analysis of muscles of the shoulder during swimming. Am J Sports Med. 1986 Jan-Feb;14(1):7-11.
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.

All You Need to Know About Inspiratory Muscles Part III

In part I and II of this series we discussed "normal" breathing biomechanics, muscles used during respiration and the current research surrounding inspiratory strength and performance.

In this installment, I will tackle my method for screening breathing and discuss the categories of respiratory strengthening exercises and a few of my favorite exercises. This will make your lungs the strong part of your swimming and lead to a successful, healthy career.

Most swim coaches are doing well training the inspiratory muscles with underwater and hypoxic training. Having to hold one's breath forces the diaphragm and secondary respiratory muscles to hold an isometric contraction. However, inspiratory isometrics can only go so far, eccentric and concentric respiration is needed to optimize swimming performance. Similar to a bicep curl, one doesn't strengthen these muscles by solely contracting their biceps, they get to LA Fitness and do curls for the girls!
Maybe Curls for the Guys...


With all the National team members at Santa Clara Swim Club I have them perform a specialized movement screen for swimmers. One aspect I closely monitor is breathing. I like to monitor relaxed inspiration/expiration and forced inspiration/expiration in standing, prone and supine. In the video, the swimmer knows I'm watching him breathe, but in reality I would not let them know what I'm looking for. This is difficult with deep breathing, but simply telling them to take a deep breath and encouraging them to take in more air brings out their competitive side and reveals their true breathing pattern.

In relaxed breathing, I look for a wave of motion, starting from the stomach rolling to the chest. Some experts suggest zero chest movement during relaxed breathing, but from experience a slight forward (not upwards) movement is fine.

During forced respiration, I make sure their diaphragm is contracting and sucking in. Make sure, they are still using their diaphragm during forced breathing.

My last screen looks at breathing during a maximal abdominal contraction. This will help differentiate the diaphragm and the abdominal muscles, indicating a week core or difficulties differentiating the diaphragm during exertion.

Four Horsemen
Different Kind of Four Horsemen
From my experience, there are four main categories to respiratory exercises. Sequentially checking one phase at a time is mandatory, as proper abdominal breathing is the foundation for the rest of the exercises.
  1. Abdominal Breathing
  2. Maximal Expiratory Contraction
  3. Maximal Abdominal Contraction with Respiration
  4. Maximal Abdominal contraction with Expiration
These four categories will help an athlete learn how to use their diaphragm during relaxed breathing, maximally contract the expiratory muscles, breathe in and out during stressful situations and solely breathe out when maximally contracting their abdominals.

Abdominal Breathing

The goal of this phase is to improve the strength of the diaphragm and differentiate the diaphragm from the secondary respiratory muscles. This form of respiratory training should use cuing and be progressed with resistance. Once differentiation is achieved, adding resistance is mandatory to strengthen this muscle.

Band Breathing

Maximal Expiratory Contraction

This phase teaches the athlete to maximally expel all the air in the body. This will get an excellent contraction of the transverse abdominus and diaphragm. This contraction will help an athlete use these muscles during fatigue. Maximal expiratory contractions will emphasize the concentric phase of these muscles, but make sure the athlete controls the eccentric phase of the contraction. Exercises should start statically (cat vomit) and progressed to dynamic movements, such as dead bugs or should flexions with maximal expiration. 

Cat Vomit

Maximal Abdominal Contraction with Respiration

Controlled breathing during a maximal abdominal contraction is essential for all elite athletes, especially swimmers. The abdominal muscles muscle be strong and stable providing a foundation for movement and athletic success. These exercises will work concentric and eccentric contraction of all the respiratory musculature during a maximal isometric abdominal contraction. Every athlete must breathe under extremely stressful situations, these exercises precisely mimic this situation.

See Maximal Contraction with Breathing Video

Maximal Abdominal Contraction with Controlled Expiration

In my opinion, this is the forgotten piece of breathing puzzles. Swimmers do a lot of hypoxic work stressing their inspiratory strength, but everyone forgets the expiratory muscles. All elite swimmers calmly expire with their face in the water (for freestyle) during highly stressful situations. They slowly release their air similar to a meditative state. Being able to breathe in a controlled fashion, will help your swimmers be relaxed during stressful situations, helping them save energy for the end of the race. These exercises should use some sort of external device (Kazoo or balloon) to ensure a constant outflow of air during a full contraction (note this athlete has a difficult time being relaxed, as noted with the jerky sound of his Kazoo).

Kazoo Abs


Well, if you've been with me for all three parts, great job grab a drink (refer to four horsemen) if needed to ease the brain cramp. But, remember cramps are potentially unused muscle fibers, so good work you're getting smarter!

By Dr. G. John Mullen, DPT, CSCS. He is the founder of the Center of Optimal Restoration and head strength coach at Santa Clara Swim Club.

All You Need to Know About Inspiratory Muscles Part II

In part I, I covered the exciting topic of breathing biomechanics and muscles associated with inspiration. These are the muscles noted with fatigue in swimming. Even though the last batch was the popular group to study, it is essential to know the other muscles involved in breathing and how to improve both forms of breathing. Now it is time to get into muscles used during relaxed and forced expiration and the research on inspiratory muscle fatigue and swimming, don't worry no statistician degree is needed.

Relaxed Expiration
As discussed in part I, the diaphragm is the main respiratory muscle. As the diaphragm contracts during relaxed inspiration, the lungs recoil back to their original position without any muscle contraction.  This is why breathing is considered an autonomous activity, it requires no thought, the body simply breathes....easy enough! The lungs are just like a like a balloon, if you blow up a balloon the outsides are stretched and forced to expand, but if you let out air, the balloon will recoil to its original position without any assistance.

Forced Expiration
Unlike relaxed expiration, forced expiration requires muscle activation.  Last weeks post on forced inspiration discussed a lot of foreign muscles, now lets talk about forced expiration and a few familiar muscle groups and a few you wouldn't expect...kegel’s baby!
  1. Internal intercostal: depresses and inverts lower ribs.
  2. Obliquus Internus: Compresses the lower part of the chest during forced expiration if the pelvis and spine are fixed.
  3. Obliquus Externus: Compresses the lower part of the chest during forced expiration if the pelvis and spine are fixed.
  4. Levator Ani: Compresses the lower part of the chest during forced expiration if the pelvis and spine are fixed.
  5. Triangularis Sterni: draws down the first rib during forced expiration
  6. Transversalis: Compresses the lower part of the chest during forced expiration if the pelvis and spine are fixed.
  7. Pyramidalis: Compresses the lower part of the chest during forced expiration if the pelvis and spine are fixed.
  8. Rectus Abdominus: Compresses the lower part of the chest during forced expiration if the pelvis and spine are fixed.

If the repeatedness didn't convey the message, these muscles are typically responsible for breathing while the pelvis and spine are fixed, stable, and stationary. This is essential and underutilized in studies which solely look at improving forced inspiration. A lot of the studies below only looked at inspiration, not looking at core stabilization, anatomy, or expiration. As you'll see in later posts, these factors are essential for optimal breathing.

Stats and Hypotheses
A lot of recent research has looked at inspiratory muscle training and inspiratory muscle fatigue and swimming performance.
  • Lomax 2011 found fatiguing of the inspiratory muscles before a 200 meter free at 85% race pace significantly affected breathing frequency, stroke rate and stroke length.
  • Brown 2011 determined there was no difference in inspiratory muscle fatigue between 100, 200 and 400 meter races. This is not surprising, since all stress the same energy systems...what about my 50 guys!
  • Kilding 2010 determined significant improvements with inspiratory muscle training, results indicated 0.6-1.7% improvement.  The largest improvements were in the 100 meter distance compared to the 400 meter distance.
  • Thomaidis 2009 looked at well trained adolescent swimmers (4:50 400 meter free time....maybe not that well trained) and determined inspiratory muscle fatigue occurs at the 300 meter distance.  This group determined as alterations in mouth pressure.
  • Jakovljevic 2009 compared breathing every two or four tims during a 90% race pace 200 meter free.  The results indicated decreased breathing, significantly increased maximal inspiratory pressure and determined inspiratory muscle fatigue is greater when breathing is reduced in front crawl swimming.
  • Mickleborough 2008 compared two groups: inspiratory muscle training plus swimming and a swimming only group. The researchers looked at lung capacities before and after 12 weeks and training and found appreciable improvements in the inspiratory muscle training and swimming group.
  • Wells 2005 determined 12-weeks of concurrent inspiratory muscle training and swimming compared to a sham respiratory training and swimming. The results showed improvements in both groups for respiratory tests.
  • Lomax 2003 found the 200 meter freestyle at 90-95% race pace induced inspiratory muscle fatigue.
Even our deep sea diving cousins have shown improved inspiratory muscle endurance with longer time to fatigue
  • Ray 2008 determined respiratory muscle training time significantly improved time to exhaustion (60%).
  • Lindholm 2007 found four weeks of inspiratory muscle training improved respiratory and fin endurance.
These studies have used various mechanisms to increase inspiratory muscle strength and found variable results. It is clear that swimming induces respiratory fatigue, but the main question remains, if swimming improves total lung capacity and forced expiratory volume (Mickelborough 2008), will additional inspirational training improve performance? Also, are the methods being used in these limited trials adequate to yield changes in elite athletes? I personally feel training these means will improve performance, but these studies have not been able to perform proper training.

I feel strengthening the diaphragm and methods where core contraction with relaxed and forced respiration need to be studied and could truly enhance inspiratory strength.  Remember, relaxed breathing should be autonomous and not call on every muscle in the body, so if you can don't utilize your primary respiratory muscles (diaphragm and intercostals), then you are fatiguing your secondary respiratory muscles, advocating the "cheater" muscles activity. Many athletes need to start simple, learning how to utilize the primary respiratory muscles with relaxed breathing, not allowing the cheaters to come around and or we'll have Joey Greco take care of them!

If one of the major breathing muscles (i.e. diaphragm) is not working properly the other muscles kick in and have to increase work. During forced respiration (athletic activities), if the primary respiratory muscles are not involved, one will be vulnerable to more injuries and stress on unnecessary structures. For example, if your diaphragm is inadequate, so your swimmer body calls on your well developed lats, pecs and traps to breathe, then these muscles will fatigue sooner, decreasing your swimming speed!

With all the boring stuff out of the way, we can tackle how to screen breathing and methods to improve both inspiratory and expiratory muscles under maximal conditions.

By Dr. G. John Mullen, DPT, CSCS. He is the founder of the Center of Optimal Restoration and head strength coach at Santa Clara Swim Club.

Friday Interview with Ricky Berens

1) Please introduce yourself to the readers (how you started in swimming,education, experience, etc.).
I am Olympic Gold Medalist Ricky Berens. I started swimming at the age of 4 on my moms summer league team in Charlotte, NC. At first I hated swimming, I hated the cold water. I would lay on the deck and just watch kids swim until about the age of 6 when I would actually start swimming laps. I guess one day I just got in the pool and said, "Hey Dad, watch me do a lap of butterfly!" and that is when it all began. I did summer league with my mom as coach until 9 when I started to swim year around at Mecklenburg Aquatic Club. I did not start winning races and being one of the top swimmers until I was about 11 or 12. Once in high school I got recruited to some of the major universities and chose to spend my college career at the University of Texas. After my sophomore year I qualified for the Beijing Olympic games by placing 3rd in the 200 free. In Beijing I was lucky enough to have the fastest time on our prelims relay and was chosen to swim it in finals where we won a gold medal and set a world record. My senior year of college at Texas was by far the biggest highlight in my NCAA career. I was captain of the winning NCAA Championship team, something that we had not been able to do the entire 4 years at school. Now I have graduated from school and am currently living in Southern California, training towards more goals of competing in the 2012 Olympic Games.

2) How do you incorporate mobility and stretching into your training?
I do a lot of stretching. I try to take about 20 minutes out of my day and just dedicate that to stretching. Now that I am done with school, I have plenty of time to do this.

3)What is the weirdest training you've done throughout your career?
Some of the weirdest training would have to be out here in CA with Dave Salo. We never do the same set with Dave and we do some of the most outside of the box things. He makes us swim with wiffle balls, do 80 meter sprints from the bottom of the deep end, up and back down again, and then there is doing flips on physio balls. All very creative fun things to mix it up.

4) What aspects of your freestyle are you currently concentrating on?
For freestyle I am really working on my head positioning and the back end of my stroke. My head tends to look a little too far forward so I am doing my best to keep my head looking directly at the bottom of the pool. This will help keep my hips floating and my body in a better line on top of the water. The more you float, the easier it is to swim. Also the back end of my stroke tends to be short, I am trying to keep it longer to extend more of a flow for my freestyle and more distance per stroke.

5) What drills/activities are you doing to achieve this?
Swimming with a snorkel always improves the head positioning, just have to make sure the head doesn't move back and forth. Swimming with paddles will really help me feel my stroke, making sure I am finishing all the way through.

6) In your opinion, what was the biggest adjustment you made in your swimming career (stroke biomechanical, training, dryland)?
All of the above. Stroke adjustments, training, and dryland. Each team I have been on we do something different than before and that is what is great. I had great training in high school to prepare me for college. In college I made some big stroke adjustments in my freestyle that really turned me into the freestyler I am today. Weights in college was something new to me, and that could never hurt. Now I am in California doing a whole different type of training which is expanding my base even more. I feel that all the adjustments I have made aren't really adjustments but me adding more and more to my swimming base and making me a better swimmer overall.

7) Of all the testing sports performance testing you've done (underwater filming, blood lactate, etc.), what do you feel has been the most beneficial?
Underwater filming. It has really helped me see what parts of my stroke I need to work on. Some of the things that you will see from underwater filming, can't be seen from the pool deck or from feel. This allows me to make sure I am getting everything I can out of my stroke, and to also compare my stroke to some of the best in the world.

8) Over the past few years, what is the biggest change you've made with your training? Intensity. It is now at a point that I am sprinting everything in practice. It doesn't matter how I feel in the water, I have to be going fast to compete with my teammates. It is justing my perspective on what fast is, which helps mentally during a race. Holding 26's for a 50 free isn't as hard as it used to be.

9) What projects are you working on in and outside the pool?
Just making sure I am qualifying for those London Olympic games! This year is all about the Olympics. I am doing everything I can to stay healthy and to prepare myself the best I can for the Olympic trials and Olympic games. Outside the pool, I guess you could say I am working on my surfing. Now that I am living close to the ocean I can go to the beach when I need a break. I would still consider it a workout too, a very fun one!

Thanks Ricky, good luck!

Want Swimming Science to interview someone, have your own questions you'd like to ask or want to be interviewed yourself? E-mail the team at info@swimmingscience.net

Hip Rotation in Breaststroke

Continuing our theme of exploring the unique physical characteristics of elite swimmers, this week we’ll look at hip internal and external rotation in breaststroke. There’s an old adage that great breaststrokers are born and not made, lets explore these adage!

Many elite breaststrokers have visible internally rotated hips, which can appear as knock-knees. Experienced coaches can sometimes identify potential breaststrokers just by looking at their lower body anatomy. In fact, Leisel Jones’ knock-knees were so extreme her family contemplated surgery to have her legs straightened.

However, it is important to recognize there is more to breaststroke kick than internally rotated hips at rest. A knock-kneed posture with internally rotated hips can be advantageous, but posture alone is not sufficient. Training the movements of hip internal and external rotation can help keep natural breaststrokers healthy and can help others improve their breaststroke kick.


While a pair of knock knees may be a cue of internal rotation, formal assessments will help identify the functional range of motion. There are several clinically accepted methods to check hip internal and external rotation, but lying prone is the most swim specific way. Although the photo sequence below uses a measuring device, coaches in a group setting can likely eyeball who has the underlying range of motion for an effective breaststroke kick. On land, our greatest concern is identifying who can’t perform the basic movement.

The first step requires finding the neutral position, this can be done by having the swimmer lie on their back. Swimmers with natural internal rotation might subjectively feel externally rotated in this position. The left side of the below picutre shows a passive test for internal rotation. Passive testing will identify whether underlying restrictions are present in the joint. Also test for active rotation, which involves the exact same movement but without manual assistance. Internal rotation deficits can lead to the common stroke flaw excessive hip abduction the in the first phase of the kick, which leads to kicking too wide.

The right side of the image shows a test for external rotation. Although the breaststroke kick in the water doesn’t reach the range of motion shown above, external rotation is the primary movement that brings the feet together at the end of the kick. Jagomagi and Jurimae (2005) found that hip external rotation was predictive of breaststroke kick speed along with knee external rotation and ankle supination. Interestingly, hip internal rotation in static posture was not correlated with kick speed, which suggests that kick improvements are more trainable than many suspect.

Injury considerations

Breaststroke related knee injuries are among the most common maladies in the sport. While the research indicates a correlation between breaststroke training volume and injury rates (Knobloch, 2008), improving hip movements will minimize stress on the knees. Ensuring adequate internal and external hip rotation will transfer the rotary stress of the breaststroke kick away from the knees and into the hips, which are better suited to handle rotary forces.
The breaststroke kick can also stress the groin if an external rotation deficit exists. A deficit could either be insufficient range of motion or a faulty movement pattern that relies on the muscles of adduction (the groin) over the muscles of rotation. Researchers at Stanford (Grote 2004) found that 42.7% of breaststrokers and 21.5% of IM-ers in a sample of 296 competitive swimmers missed practice time due to groin pain. (note, the lead researcher in this study was Olympic gold medalist breaststroker Dr. Kurt Grote, M.D.).


Breaststroke specialists may seem like the anatomical freak shows of the pool, but improvements in hip internal and external rotation are possible for swimmers of all ages. In the next installment we’ll cover dryland strategies to improve these aspects of hip performance.


  1. Jagomägi, G. Jürimäe, T. The influence of anthropometrical and flexibility parameters on the results of breaststroke swimming. Anthropol Anz. 2005 Jun;63(2):213-9
  2. Knobloch, K. Yoon, U. Kraemer, R. Vogt, PM. 200-400m breaststroke dominate among knee overuse injuries in elite swimming athletes. Sportverletz Sportschaden. 2008 Dec;22(4):213-9. Epub 2008 Dec 15.
  3. Grote, K. Lincoln, TL. Campbell, JG. Hip Adductor Injury in Competitive Swimmers. Am J Sports Med. 2004 Jan-Feb; 32(1): 104-08.
By Allan Phillips. Allan and his wife Katherine are heavily involved in the strength and conditioning community, for more information refer to Pike Athletics.