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

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Speed of Breathing Predicts 100-m Performance

Take Home Points on Speed of Breathing Predicts 100-m Performance

    1. The faster a national caliber swimmer can exhale air in 1 second is correlated with 100-m performance.

    Everyone is trying to predict athletic performance in youth athletes. Not unlike other
    sports, swimming research has looked at many attributes of youth swimmers, including height, strength, and lean body mass. Dr. Barbosa has lead most of this research and discussed it on this website previously

    Breathing is a unique process in swimming due to it’s hypoxic nature. Swimming practice improves pulmonary function and swimmers show higher lung volumes and pulmonary diffusion capacity compared with both nonathletic and athletic peers from other sports. This has led many to consider inspiratory muscle training. However, the forced inspiratory volume is another important factor as the faster a swimmer can breathe in air, the more air they can hold per breath and limit their breathing which often increases drag and prevents biomechanics. However, few studies have looked the relationship of respiratory capacity and sprint swimming performance.

    Seventeen national competitive swimmers (M=8, F=9; ~16.9 years) with personal records in the 100 m at 56.1 seconds for male and 65.2 seconds for female. All swimmers have been swimming 6 days per week for the past 3 years. 

    After a standard warm-up, each swimmer performed a 100-m all-out trial. Swimmers also had their physiological parameters of lung function measured using a spirometer. The subjects performed maximal inspiration followed by enforced exhalation three times. 

    Anthropometric data was also measured for each swimmer. On top of this, squat jump and countermovement jump were assessed.

    Study Results

    The male swimmers were older, taller, and heavier, with less adipose tissue than the females. Also, the males were faster in the 100-m time trial, had a higher height in squat jump and countermovement jump and nearly all pulmonary functions, except forced expiratory volume in the first second (FIV1)/forced vital capacity (FVC) and forced inspiratory volume (FIV). 

    FIV1 was negatively correlated with 100 m time trial in men and FIV1 and FVC were negatively correlated with time trial in female swimmers.

    Anthropometrics and conditional variables did not show a significant correlation in the swimmers. 


    This is the first study to demonstrate the influence of FIV1 in 100 m performance. FIV1 likely aids performance by allowing the swimmer to inhale air quicker and increase the amount of air they can inhale in a limited time. Swimmers with high FIV1 may need less respiratory frequency, produce less inspiratory muscle fatigue, increasing active limbs blood flow and reducing fatigue in these limbs, and consequently may improve performance.

    It seems inspiratory muscle training would improve swimming velocity, which has been suggested in the recent literature. 

    Practical Implication

    Respiratory capacity should be assessed by swim teams, if looking for predicting performance. Also, coaches must consider using inspriatory muscle training.  


    1. Noriega-Sánchez SA, Legaz-Arrese A, Suarez-Arrones L, Santalla A, Floría P, Munguía-Izquierdo D. FORCED INSPIRATORY VOLUME IN THE FIRST SECOND AS PREDICTOR OF FRONT CRAWLPERFORMANCE IN YOUNG SPRINT SWIMMERS. J Strength Cond Res. 2014 Jul 21. [Epub ahead of print]

    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 where he swam collegiately. He is the owner of COR, Strength Coach Consultant, Creator of the Swimmer's Shoulder System, and chief editor of the Swimming Science Research Review.

    Exhale-Hold, the True Hypoxic Training

    The newest edition of the Swimming Science Research Review was released today. The theme of this edition is physiology, make sure to order your copy to stay current with the latest research on dry-land. Below are the tables of contents of this edition.

    August Swimming Science Research Review Tables of Contents
    1. “Exhale-Hold” Breathing Causes Hypoxia | RESPIRATORY TRAINING
    2. 25-KM Doesn’t Cause Maximal Fatigue | ENDURANCE PHYSIOLOGY
    3. Swimming Doesn’t Increase Neurogenic Inflammation | ASTHMA
    4. Forced Inspiratory Volume Correlates with 100-m Performance | RESPIRATORY
    5. Deep Breathing Elicits Recovery | RESPIRATORY TRAINING
    6. Metabolic Testing in Swimmers is Flawed | METABOLIC TESTING
    7. High-Intensity Swim Training Improves Cardiac Health | CARDIOVASCULAR SYSTEM
    8. High-Intensity and Traditional Training Don’t Improve Performance | TRAINING
    9. 200-m Assesses Aerobic Capacity in Youth Swimmers | PHYSIOLOGY
    10. Arterial Load is Different in Men and Women | PHYSIOLOGY
    11. Physiological Alterations in Swimming are Small | PHYSIOLOGY
    12. More LBM Improves HRV | NERVOUS SYSTEM
    13. Too Long Self-Regulated Recovery is Taken | RECOVERY
    14. Faulty Breathing is Common | RESPIRATORY TRAINING
    15. Circadian Rhythm is Sensitive to Heavy Exercise | PHYSIOLOGY
    Physiology is one of the older exercise science topics, yet it is far from well understood.
    As you’ll see in this publication, many ground breaking discoveries still occur, especially when the swimming specific aspects.

    Most notable in this publication is the research by Dr. Xavier Woorons on hypoxia and breathing. As we discussed a while back, traditional hypoxic training is actually hypercapnic training. Instead, “exhale-hold” techniques elicit a hypoxic environment which appears to increase anaerobic stress and lactate build-up.

    Now, before we write off “inhale-hold” training, it seems there is a new technique which may compliment the old form of training. However, like all research, we need to know more, especially with the possibility of drowning.

    Nonetheless, new techniques still occur in physiology! Take enjoyment in these novelties and practice them yourself or with your team, just perform them safely and track the results!

    1. Woorons X, Gamelin FX, Lamberto C, Pichon A, Richalet JP. Swimmers can train in hypoxia at sea level through voluntary hypoventilation.
      Respir Physiol Neurobiol. 2014 Jan 1;190:33-9. doi: 10.1016/j.resp.2013.08.022. Epub 2013 Sep 4.
    The influx of online information makes it difficult to stay up-to-date with informative, accurate research studies. The Swimming Science Research Review brings you a comprehensive research articles on swimming, biomechanics, physiology, psychology, and much more!
    This monthly publication keeps busy coaches and swimming enthusiast on top of swimming research to help their programs excel, despite being extremely busy. 


    Need More Recovery During Taper, Consider Deep Breathing!

    Take Home Points on Need More Recovery During Taper, Consider Deep Breathing!
    1. Swimmers have a stronger response to deep breathing.
    2. Deep breathing may enhance recovery in swimmers.
    Swimming Science has suggested breathing exercise for swimming and recovery enhancement for years. All of my swimmers at COR receive breathing regimens for the potential swimming enhancement (via enhanced inspiratory muscle strengthening), but also the recovery.

    Heart rate variability (HRV) is a non-invasive technique that can look at the function of the autonomic nervous system (ANS). Sympathetic impulses increase heart rate by exciting the sinoatrial (SA) node while parasympathetic impulses reduce heart rate by inhibiting it.

    Deep breathing (DB) is a reliable and sensitive measure of cardiovagal and parasympathetic function. Elite endurance athletes typically have more pronounced respiratory sinus arrhythmias.

    Unlike other sports, swimming requires frequent breath holding during the stroke cycle and during extended periods underwater.

    Palak (2013) had ten professional swimmers (M=5, F=5; ~21 years) and ten controls, not previously or currently in a sports discipline. The control group averaged two 60-minute exercise sessions per week.

    After a 20-minute rest while lying down, a 10-minute electrocardiogram (ECG) was recorded. Each participant was asked to breathe deeply for 5 minutes, with a frequency of 6 breaths/minute (5 second inspiration, 5 second expiration). ECG was continuously recorded during this period.

    Swimmers had higher rMSSD (square root of the mean squared difference of successive R-R interval), pNN50 (proportion of successive R-R intervals that differ by more than 50 ms), LF (low frequency component 0.04-0.15 Hz), and HF (high-frequency component (0.15-0.4 Hz) than persons without physical training at rest. A longer R-R interval of the sinus rhythm and lower heart rate were noted in the experimental group compared to the control.

    The swimmers also showed a stronger response to DB than individuals who neither currently or previously practiced a sport.

    What does Deep Breathing do for Swimmers?

    The differences in resting HRV indices of swimmers suggests different arterial baroreceptor reflex sensitivity compared to controls. Also, swimmers showed a greater response to DB, this likely aids recovery.  

    During periods of heavy training, deep breathing may elicit the parasympathetic nervous system and aid recovery in professional swimmers. If a swimmer is having difficulties recovering for practice or if you need more recovery during taper, consider deep breathing!

    Future studies must compare swimming results with and without a deep breathing recovery.

    1. Palak K, Furgala A, Ciesielczyk K, Szygula Z, Thor PJ. The changes of heart rate variability in response to deep breathing in professional swimmers. Folia Med Cracov. 2013;53(2):43-52.

    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 where he swam collegiately. He is the owner of COR, Strength Coach Consultant, Creator of the Swimmer's Shoulder System, and chief editor of the Swimming Science Research Review.

    Friday Interview: Dr. Xavier Woorons Discusses Hypoventilation Training in Swimming

    1. Please introduce yourself to the readers (how you started in the profession, education, credentials, experience, etc.).
    My name is Xavier WOORONS, I am a PhD in Human Biology, specialized in exercise physiology, in particular in the physiological responses to hypoxia and hypoventilation (exercise and training). I’ve been working for 10 years in the laboratory “cellular and functional responses to hypoxia” of Paris 13 University.

    2. You recently published an article hypoxia, first can you explain your methods and how you induced hypoxia?
    In our recent article, we demonstrated that swimmers can really train under hypoxic conditions at sea level if they use a hypoventilation technique at low lung volume. The breathing technique consists of performing short breath holdings with the lungs half full of air. To do so, swimmers have to first exhale then hold their breath for a few seconds. This is called the"exhale-hold" technique. Using an innovative device that allows the continuous measurement of blood oxygenation, we have shown that the exhale-hold technique could lead to a drop in arterial oxygen saturation (SaO2) similar to what is generally recorded above 2000m.

    3. What are some misconceptions in the swimming community about breath holding and hypoxia?
    Since the early 1970’s, at the instigation of the American trainer James Counsilman, many swimmers have included in their training sessions exercises with restricted breathing. Generally, these exercises consist of swimming with fewer breaths relative to arm strokes (i.e. inhale every 5, 7, or 9 strokes instead of 2–3 strokes). This method has been called, and is still called by many coaches and swimmers, “hypoxic training”. However, this is misleading because so far, no study had ever demonstrated that reducing the breathing frequency during a swimming exercise could induce hypoxia. In fact, only a hypercapnic effect (higher CO2 concentrations) had been reported. In our research, we showed that swimmers cannot obtain a significant hypoxic effect when they use hypoventilation at high lung volume, that is when they hold their breath with the lungs full of air (inhalation then breath hold).

    4. What were the main results of your study?
    Our study brings several novelties:

    1) For the first time, we have managed to continuously measure oxygen concentrations in exercising swimmers thanks to a waterproofed forehead sensor placed under the swimming cap and connected to an oximeter maintained out of the water. The former studies could assess O2 levels only after the exercise, either through a blood sampling or a digital or ear sensor. However, these kinds of measurements are not very reliable since SaO2 rapidly returns to normal levels (or close) after the exercise. The continuous measurement of SaO2 through a forehead sensor is interesting because it enables to explore new areas of research in swimming.

    2) We showed that SaO2 could drop to 87% on average when swimmers used the exhale-hold technique. This level of SaO2 is generally recorded during moderate exercise performed at an altitude of about 2400m. On the other hand, SaO2 remained above 94% during the majority of exercise, when swimmers used the classical technique of hypoventilation applied since the 1970's (inhale-hold). This level of SaO2 cannot be considered as a hypoxic effect.

    3) Performing hypoventilation with the exhale-hold technique led to a greater increase in lactate concentrations, and therefore a greater stimulation of anaerobic metabolism, than the exercise performed with normal breathing. Conversely, with the inhale-hold technique, lactate concentrations were lower than during exercise with normal breathing, thus reducing the stimulation of anaerobic metabolism.

    5. What can coaches take from your research?
    First, if coaches want their swimmers to really train under hypoxic conditions while remaining at sea level, they must replace the former hypoventilation technique (inhale-hold), used for about 40 years, by the hypoventilation technique at low lung volume (exhale-hold). After several weeks of hypoventilation training with the exhale-hold technique, the physiological adaptations that occur may delay fatigue and improve performance, as already shown in runners. Thus, swimmers may find an interest to include two or 3 times a week hypoventilation exercises over distances between 25 and 100m.

    Second, coaches have to be aware that, through the exhale-hold technique, it is possible for swimmers to stimulate the anaerobic metabolism by using low or moderate exercise intensities. This could avoid to systematically using high speeds during training, which can be more traumatizing for the locomotor system. This feature could also be interesting for injured swimmers who must return progressively to their swimming activity. Using the exhale-hold technique, these swimmers could stimulate the anaerobic glycolysis without putting too much stress on their muscles, joints or tendons. Thus, this would allow them to return to a satisfactory level of performance more rapidly.

    6. Can hypercapnea training also help swimmers?
    At first sight, the effectiveness of hypercapnea training may be questionable. In fact, it appears that many coaches use this kind of training to increase the tolerance to hypercapnia in their swimmers and therefore to make them breathe less frequently during a race. Breathing less frequently could be interesting in swimming since each time you turn the head to inhale, hydrodynamic disturbances as well as discontinuity in propulsive actions occur. Consequently, drag and energy cost are greater. If swimmers are able to restrict their breathing during a race, they could reduce drag and thus save energy, which might, theoretically, improve performance by a few tenths of seconds.

    However, I think that hypercapnia training may be interesting for another reason. Indeed, it is well known that high CO2 concentrations provoke acidosis in the body. After several sessions of hypercapnia training, physiological adaptations, such as better buffering capacity, may occur and allow reducing acidosis. My thesis is that this phenomenon can be exacerbated if you add the hypercpanic effect to the hypoxic effect, like when using the exhale-hold technique. Therefore, through hypoventilation training at low lung volume, swimmers could obtain strong physiological adaptations that may delay fatigue and finally improve performance.

    7. Can hypoxic training help facilitate warm-up?
    If you don't mind, I will call it hypoventilation training rather than hypoxic training considering the fact that there is a combined effect of hypoxia and hypercapnia. As I mentioned above, this kind of training elevates the level of acidity in the body and can therefore lead to fatigue. Consequently, I would not say that it can help facilitate warm-up. It could even be the contrary if hypoventilation is too strong.
    However, hypercapnia and hypoxia also induce muscle vasodilatation, which can increase oxygen supply. As such, one could hypothesize that performing a light hypoventilation may improve warm-up.

    In fact, I don't know the real effects because to my knowledge, no study has ever been published on this subject. This should be investigated in the near future.

    8. One other question, there is a lot of research emerging of the benefits of inspiratory muscle training for swimmers. What do you think? Also, do you know of any practical methods of inspiratory training for those without equipment?
    In swimming, the work of breathing is greater than in land-based sports because of the hydrostatic pressures. It is well known that swim training leads to large improvement in pulmonary function, and this, without inspiratory or, more generally, respiratory muscle training. However, during exhaustive exercise, it has been shown that inspiratory muscle fatigue occurs in some swimmers and over certain distances. Therefore, this could constitute a limiting factor to performance. In this case, I think that respiratory muscle training may be useful and may represent an ergogenic aid for swimmers.
    In a recent study published by Lavin et al. (2013), it was hypothesized that limiting breath frequency during swimming could mimic the effects of respiratory muscle training. This assumption is based on the fact that hypoventilation during exercise further stresses the respiratory system through hypercapnia and mechanical loading. However, the results of the study showed no improvement in respiratory muscle function. Even though further studies are needed, I am not convinced that reducing the breathing frequency during training could represent an effective practical method for improving respiratory muscle strength without any equipment.

    9. What research or projects are you currently working on or should we look from you in the future?
    I will continue to work on hypoventilation training in the next few years. Currently, the project is to determine the effects of the exhale-hold technique on performance in swimmers. In the future, our goal is to find the optimal weekly training frequency of hypoventilation training, set intensity and set duration for improving performance in different sporting activities.

    I would like to end this interview by saying that I have just published a book on hypoventilation training: "hypoventilation training, push your limits!". This book presents all the knowledge currently available on this training method and proposes tools for athletes who would like to include it in their training program. You can find all the information on this website: http://www.hypoventilation-training.com/

    Inspiratory Muscle Fatigue Impairs Latissimus Dorsi Strength

    Take Home Points on the Inspiratory Muscle Fatigue Impairs Latissimus Dorsi Strength

    1. Inspiratory muscle fatigue impairs latissimus dorsi activation, likely reducing swimming motor control and propulsion.  

    Breathing is a frequent topic of discussion at Swimming Science. Before we get started, first brush up on:
    Lomax (2003) first demonstrated that a 200-m race results in inspiratory muscle fatigue. Him and his team of researchers then noted inspiratory muscle fatigue before a 200-m race impaired performance (Lomax 2010). Inspiratory muscle fatigue also occurs for other competitive sports (Lomax 2012). However, the specifics of inspiratory muscle fatigue and performance are not well understood. 

    Lomax (2014) had eight collegiate swimmers (M=6, F=2; ~22.0 years; mean 200 m freestyle 139 seconds) were recruited to perform two maximal 20 s arms only front crawl sprints in a swimming flume. Both sprints were performed on the same day and inspiratory muscle fatigue was induced 30 minutes after the first sprint. They measured maximal inspiratory and expiratory mouth pressures pre and post each sprint. The median frequency (MDF) of the electromyographic signal burst was recorded from the latissimus dorsi and pectoralis major during the 20 s sprint, along with stroke rate and breathing frequency.

    After inspiratory muscle fatigue, stroke rate increased from 56 to 59 cycles/min. Latissimus dorsi MDF decreased from 67 to 61 Hz. No change was observed in the MDF of the latissimus dorsi during the control sprint. The MDF of the pectoralis major shifted to lower frequencies during both sprints, but was unaffected by inspiratory muscle fatigue.

    It seems inspiratory muscle fatigue only negatively influences the latissimus dorsi muscles in arms only sprint swimming. This likely decreases propulsion in freestyle and may be a main cause for impaired performance. Another interesting finding is that the pectoralis major fatigues during a 20-second sprint. Now, keep in mind breathing more frequently reduces inspiratory muscle fatigue...(Jakovljevic 2009). 

    1. Lomax M, Tasker L, Bostanci O. Inspiratory muscle fatigue affects latissimus dorsi but not pectoralis major activity during arms only front crawl sprinting. J Strength Cond Res. 2014 Jan 7. [Epub ahead of print]
    2. Lomax ME, McConnell AK. Inspiratory muscle fatigue in swimmers after a single 200 m swim. J Sports Sci. 2003 Aug;21(8):659-64.
    3. Lomax M, Iggleden C, Tourell A, Castle S, Honey J. Inspiratory muscle fatigue after race-paced swimming is not restricted to the front crawl stroke. J Strength Cond Res. 2012 Oct;26(10):2729-33.
    4. Lomax M, Castle S. Inspiratory muscle fatigue significantly affects breathing frequency, stroke rate, and stroke length during 200-m front-crawl swimming. J Strength Cond Res. 2011 Oct;25(10):2691-5. doi: 10.1519/JSC.0b013e318207ead8.
    5. Jakovljevic DG, McConnell AK. Influence of different breathing frequencies on the severity of inspiratory muscle fatigue induced by high-intensity front crawl swimming. J Strength Cond Res. 2009 Jul;23(4):1169-74. doi: 10.1519/JSC.0b013e318199d707.
    Written by G. John Mullen who received his Doctorate in Physical at University of Southern California (USC) and is a certified strength and conditioning specialist (CSCS). At USC, he was a clinical research assistant performing research on adolescent diabetes, lung adaptations to swimming, and swimming biomechanics. G. John has been featured in Swimming World Magazine, Swimmer Magazine, and the International Society of Swim Coaches Journal. He is currently the owner of COR, providing Physical Therapy, Personal Training, and Swim Lessons to swimmers and athletes of all skills and ages. He is also the creator of the Swimmer's Shoulder SystemSwimming ScienceSwimming Science Research ReviewMobility System and the Swimming Troubleshooting System.

    Friday Interview: Jernej Kapus Discusses Breathing

    1. Please introduce yourself to the readers (how you started in the profession,
    education, credentials, experience, etc.).
    I am coming from Ljubljana, Slovenia. I’m an Assistant Professor at the University of Ljubljana, Faculty of Sport. I spent most of my childhood in competitive swimming. My
    swimming career was ended during the third year of study at University of Ljubljana, Faculty of Sport. After finishing Bachelor degree (1999), I continued the study at Master (2004) and Doctor Level (2008). All that time I have been interested mainly in the influences of reduced breathing during swimming. During the final part of my swimming career I often manipulated with breathing at front crawl and fly swimming. At the beginning it was very hard to reduce from usual (take a breath every second stroke cycle at front crawl or every stroke cycle at fly) to less breathing during swimming (take a breath every third, fourth, fifth stroke cycle at front crawl or every second stroke cycle at fly). However, after few training sessions I was adapted to these reduced breathing and improved swim times in these techniques as well. Considering these experiences, I chose this topic for my further research work. I started with the analysing the acute (reduced breathing during maximal or submaximal swim) and continued with the training effects.

    2. You recently published an article breathing frequency and endurance exercise. What lung adaptations are we confident that occur during restricted breathing frequency and swimming?
    Swimming produces unique challenges for breathing system i.e. breathing musculature and lung. Swimmers exercise in a horizontal or near horizontal position and are subjected to hydrostatic forces. Furthermore, swimming requires the ability to tightly regulate breathing pattern and flow rates that are much higher than during dry-land exercises. Considering this, the higher lung volumes are the expected consequences of regular swimming training. In our recent study, it was obtained that six weeks of cycle ergometry interval training with reduced breathing frequency (3 training session per week) increased vital capacity for 8 ±8%. However, it should be emphasis that the subjects were students at Faculty of sport with no experiences in competitive swimming.

    3. What did your study look at?
    The aim of the mentioned study was to investigate the influence of training with reduced breathing frequency (RBF) on tidal volume during incremental exercise where breathing frequency was restricted and on ventilatory response during exercise when breathing a 3% CO2 mixture.

    4. Were these athletes already trained?
    Twelve healthy male participants participated in this study. As students at Faculty of Sport, they were active but none were currently participating in a regular training programme. During the study period, they stopped their usual physical activity (recreational) and only exercised during the training sessions as part of the experiment.

    5. What were the main results of your study?
    The conclusion of this study was that, the effect of RBF training during cycle ergometry was twofold. It increased tidal volume during incremental exercise where breathing frequency was restricted. In addition, it decreased the ventilatory response to exercise when breathing a 3% CO2 mixture, which suggests an increased tolerance to CO2 following such training.

    6. How does this research help the coaching community?
    The data suggest that swim training with RBF might permit swimmers to take fewer breaths and to hold their breath for longer, which would be of particular benefit during the underwater phases (flip turns, gliding, and underwater strokes) as well as providing an important biomechanical advantage. However, RBF training could not be realized during high velocity swimming due to the additional stress caused by such a breathing pattern. Therefore, it seems that the combination of the two forms of intense front crawl training under different breathing conditions (swimming with RBF at a lower velocity, and swimming with the usual breathing frequency at higher velocities) would be beneficial for competitive swimmers.

    7. What questions still exist on lung adaptations to swimming?

    Although the adaptations of lung volumes are relevant to all athletic groups the impact of inspiratory muscle training (via increasing inspiratory muscle strength) on swimmers is particularly interesting in the recent studies.

    8. What questions remain about reduced breathing frequency and other endurance training?
    As mentioned above it should be investigated the effects of RBF training performed at different intensities on swimming performances.

    9. Inspiratory muscle training is gaining evidence for improving swimming performance, what do you think about inspiratory muscle training in swimmers?
    Since we have known that inspiratory muscle fatigue occurs during swimming, even in very well trained swimmers, it seem reasonable to include inspiratory muscle training in regular swimming practice. Furthermore, I believe that inspiratory muscle training could offer some potential benefits for ability to exercise with RBF. Indeed, our preliminary results indicate that inspiratory muscle training does increase ventilation (via tidal volume) during incremental exercise with RBF.

    10. What research or projects are you currently working on or should we look from you in the future?
    In collaboration with Dr. Mitch Lomax [see his interview] from University in Portsmouth and dr. Anton Ušaj from University of Ljubljana, Faculty of sport we have some swimming projects going on  at present as well as some non-swimming breathing muscle projects. Swimming projects include how to incorporate inspiratory muscle training into swimming training programmes for long term benefits and the determination of changing the swimming technique as a consequence of respiratory acidosis during swimming with RBF. In other research project we will try to determine inspiratory muscle fatigue during exercise with RBF. Furthermore, it is needed to establish the efficacy of inspiratory muscle training as a supplement to regular exercise training with or without RBF.

    Brief Swimming Review Edition 17

    In an attempt to improve swimming transparency, this brief swimming review will be posted on Saturday. If you enjoy this brief swimming review, consider supporting and purchasing the Swimming Science Research Review for complete monthly article review for only $10/month! Click here to purchase past issues and the most recent review discussed core stability.

    Rotator Cuff Imbalances in Swimmers

    Should rotator cuff muscle imbalances are well documented in swimmers. However, the effect of this imbalance after a period of detraining is not well understood, this study looked at the influence of a detraining period on shoulder rotator cuff muscle imbalances.
    An experimental group (n=20) and a control group (n=20) of young male swimmers (~14 – 15 years) had their peak torques of their shoulder internal and external rotators assessed pre-season, mid-season, and post-season (32 weeks). The experimental group underwent a strength training regimen from baseline to 16 weeks and a detraining period from 16 – 32 weeks (Batalha 2013). 
    At 60 degrees per second, there were significant increments in IR strength and the ER/IR ratio in both shoulders. This trend was the same throughout the competitive season. These occurrences also existed at 180 degrees/second. During the period of no land-based strength training, a reduction in the ER/IR values occurred for both shoulders.

    Take Home Points of Shoulder Imbalances

    1. Coaches should use shoulder strengthening to decrease the amount of shoulder rotator cuff imbalance. 
    2. Specifically, exercises targeting the external rotators and scapular stabilizers should be utilized. 
    For more specifics, consider purchasing the COR Swimmer's Shoulder System.

    Youth Biomechanics in Backstroke

    Swimming biomechanics are believed to be the largest contributor to swimming biomechanics. Most of the biomechanics research has been in adults, not children. Children and youth swimmers are believed to have different swimming biomechanics due to different anthropometrics compared to adults. Backstroke doesn’t gain much attention in the literature, as freestyle dominates the field of research. Of the backstroke research, it is believed elite backstrokes show an absence or low lag time at the thigh. This study attempted to characterize the biomechanics of backstroke used in 11 – 13 year-old swimmers at a very high intensity.

    A sample of 114 swimmers was divided into four groups regarding maturational and gender effect. Each of these swimmers performed a 25-m backstroke at 50- pace. The swimmers were recorded with two underwater cameras (Silva 2013). 

    Post-pubertal swimmers achieved higher values of speed, stroke length, and stroke index. Males were faster than females. Boys also showed a higher stroke rate and stroke index than girls, who achieved higher results in the ratio between stroke length and arm span.

    Take Home Points on Youth Backstroke Biomechanics

    1. Age-group swimmers show similar lag times compared to adults, but lack stroke length, and stroke index. 
    2. Coaches should stress stroke length and biomechanics for improvement.

    Respiratory Training Improves Swimming Performance

    Respiratory muscle endurance training (RMET) has conflicting research at the moment, as some studies suggest it is beneficial, while others dismiss its use.

    Two homogenous groups of ten swimmers (M=13, F=7; between 13 – 18 years) were split into a RMET or non-RMET group over an eight week period. During this time period, the swimmers had the same training sessions 5 – 6 times/week. Respiratory muscle strength and endurance, performances on 50- and 200-trials, effort perception, and dyspnea were assessed before and after (
    Lemaitre 2013)

    The RMET consisted of the use of a SpiroTiger, which helps prevent hypocapnia despite hyperventilation. The training consisted of 30-min of TS per day, five days per week.

    The results showed that ventilator function parameters, chest expansion, respiratory muscle strength and endurance, and performances were improved only in the RMET group. Moreover, perceived exertion and dyspnea were lower in the RMET after both the 50- and 200-m. 

    Take Home Points on Respiratory Training

    RMET appears beneficial for youth swimmers, as it improves performance by 3 – 4%. Future studies must compare it to another modality, like core training, visualization, or strength training.


    1. Batalha NM, Raimundo AM, Tomas-Carus P, Marques MA, Silva AJ. DOES AN IN-SEASON DETRAINING PERIOD AFFECT THE SHOULDER ROTATOR CUFF STRENGTH AND BALANCE OF YOUNG SWIMMERS? J Strength Cond Res. 2013 Dec 16. [Epub ahead of print]
    2. Lemaitre F, Coquart JB, Chavallard F, Castres I, Mucci P, Costalat G, Chollet D. Effect of Additional Respiratory Muscle Endurance Training in Young Well-Trained Swimmers. J of Sports Sci and Med. 2013 Dec; 12, 630 – 638.
    3. Silva FA, Figueirdo P, Seifert L, Soares S, Vilas-Boas JP, Fernandes RJ. Backstroke Technical Characterization of 11 – 13 Year-Old Swimmers. J Sports Sci and Med. 2013 Dec; 11, 623-629. 
    G. John Mullen received his Doctorate in Physical at University of Southern California (USC) and is a certified strength and conditioning specialist (CSCS). At USC, he was a clinical research assistant performing research on adolescent diabetes, lung adaptations to swimming, and swimming biomechanics. G. John has been featured in Swimming World Magazine, Swimmer Magazine, and the International Society of Swim Coaches Journal. He is currently the owner of COR, providing Physical Therapy, Personal Training, and Swim Lessons to swimmers and athletes of all skills and ages. He is also the creator of the Swimmer's Shoulder System, Swimming Science, Swimming Science Research Review, Mobility System and the Swimming Troubleshooting System.

    The Best Way to Breathe in Butterfly

      Take Home Points on The Best Way to Breathe in Butterfly

      1. Forward breathing is the best practice for butterfly breathing.
      Differences in swimming biomechancis will always exist, I mean who would think Andrew Selkisar should have the same biomechanics as Alain Bernard? This makes individualization for each person mandatory, as anthropometrics will determine stroke biomechanics.
      A tad more muscular than the young Selkisar

      However, there are some biomechancis which should be followed for the majority of swimmers, as the average typically encompasses most swimmers. A few weeks back we broke down how to swim the butterfly. In this piece, a the main tips on breathing included:

      "• The head and shoulders should rise the least amount possible and be completed by the middle of the propulsive phase of the arm strokes. Once again, streamline is paramount, don't disrupt streamline [see Phelps below]!

      • The hips should remain at the surface even in the breathing action. High hips keeps the body moving downhill, while maintaining streamline.

      • The chin should be thrust through the bow-wave on the water's surface [see Phelps below]."

      As you can see in the photo of the great Phelps, to keep the chest down, the head must breathe forward and attempt to be low enough to thrust through the bow-wave. 

      Some of you may have seen swimmers attempt to keep their head down during their breath or rotate their head to the side. These biomechanical adjustments may work for some, but may also come at a praice, which we'll breakdown in this how to breathe in butterfly piece!

      Cervical Spine Mobility for Butterfly Breathing


      The cervical spine is estimated to have ~48 degrees of extension range of motion (Piva 2006). A large degree of extension is believed to occur at the joint between the head and the first cervical spine segment (the atlanto-occiptal joint). The atlanto-occiptal joint is believed to account for ~10 - 15 degrees of extension (Kottke 1959; Brocher 1955). With most of the cervical extension occuring at this high cervical segment, the amount of disruption or association thoracic extension is likely minimal.



      Rotation is another story and most of cervical spine, as most of the motion occurs at the segment below the atlanto-occipital joint, the atlanto-axial joint. As you can see below, nearly all of rotation occurs at this segment, making it clear minimal rotation occurs below this joint. 

      However, This axial rotation was accompanied by 14 degrees of extension and 24 degrees of contralateral lateral flexion, although the authors reported that in some cases flexion would accompany the axial rotation rather than extension (Mimura 1989). These coupled motions may cause biomechanical flaws while breathing, potentially increasing drag.

      Associated Motions of the Cervical Spine

      The spine is an intricate structure which contains natural curves. These curves help keep the body upright. These units also influence each other, as moving at one joint influences the surrounding segments. For example, if the head extends, it is believed the lower thoracic spine also undergoes some degree of extension. Also, as the neck extends, other motions occur (the coupled motions  noted above). 

      Unfortunately, those performing head down breathing or side breathing likely don't take these coupled or associated motions into account. Also, not extending from the neck requires the body to extend from somewhere else... 

      Head down Butterfly Breathing

      When the cervical spine does not move for a breath, the spine must move elsewhere. Overall the thoracic spine doesn't have much range of motion, leaving the body to use the low or lumbar spine. If this area extends, it raises all the segments above, can you say hello drag? Think about it (of just lean back), if you extend from the lumbar spine our chest goes up, undoubtedly creating drag in the water. Though your head may be lower, your chest is likely in a higher drag position. 

      Which position looks like it creates more drag....

      Side breathing?

      Side breathing is a whole other story. If someone is capable of timing the side breath it can be helpful, as it should keep the chest low in the water and not enduce too much extension (once again some have extension while others have flexion during coupled motions of the spine). 

      Yet, thinking of all the movement consequences is necessary. If you rotate your head to the right and have the associated countralateral side bend (side bend left), it is likely the rest of your spine may follow suit and perform this motion. Also, this awkward head motion may also be difficult as the rest of the spine is undergoing saggital plane motion (flexion and extension), but the neck is doing an axial rotation ... are most swimmers this coordinated?

      Unfortunately, many people have difficulties learning this technique if they aren't taught this early in their swimming career. Another issue with side breathing is swimming straight and having a symmetrical arm entry.

      Butterfly breathing Summary

      Now, this isn't to suggest everyone butterflyer must breathe forward, as there are always exceptions. For example, those who are taught to breathe to the side at a young age and have the coordination for this movement may excel with it. Also, if a swimmers have emaculate thoracic spine and cervical spine dissociation and the great thoracic spine mobility, the head down butterfly technique is possible. However, the most commonly successful breathing technique is forward and it makes biomechanical sense!


      1. Piva SR, Erhard RE, Childs JD, et al: Inter-rater reliability of passive intervertebral and active movements of the cervical spine, Manual Th er 11(4):321-330, 2006. 
      2. Kottke F J, Mundale M 0 1959 Range of mobility of the cervical spine. Archives of PhySical Medicine and Rehabilitation 40: 379-382.
      3. Brocher JEW 1955 Die occipito-cervical-gegend: eine diagnostiche pathogenetische studie. Georg Thieme Verlag, Stuttgart.
      4. Penning L, Wilmink J T 1987 Rotation of the cervical spine: a CT study in normal subjects. Spine 12: 732-738.
      5. Mimura M, Moriya H, Watanabe T, Takahashi K, Yamagata M, Tamaki T 1989 Three-dimensional motion analysis of the cervical spine with special reference to the axial rota tion. Spine 14: 1135-1139.
      6. Rushall, BS. A swimming technique macrocycle. 2013: Spring Valley, CA; Sports Science Associates [Electronic book].
      G. John Mullen received his Doctorate in Physical at University of Southern California (USC) and is a certified strength and conditioning specialist (CSCS). At USC, he was a clinical research assistant performing research on adolescent diabetes, lung adaptations to swimming, and swimming biomechanics. G. John has been featured in Swimming World Magazine, Swimmer Magazine, and the International Society of Swim Coaches Journal. He is currently the owner of COR, providing Physical Therapy, Personal Training, and Swim Lessons to swimmers and athletes of all skills and ages. He is also the creator of the Swimmer's Shoulder System, Swimming Science, Swimming Science Research Review, and the Swimming Troubleshooting System.