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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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Progressive Overload in Elite Swimmer

Take Home Points on Progressive Overload in Elite Swimmer

  1. Progressive overload contributes to success in swimming after maturation.
  2. Elite swimmers require continual progressive overload for gains.

Novice swimmers are constantly pushed. Pushing during warm-up to kick sets, produce overload during the traditional form of training. Elite swimmers can perform many training sets without much stress. This complacency can impede performance as overload doesn't occur. Many elite swimmers still improve ~3 - 4% during puberty (Sweetenham 2013). Once maturation halts many swimmers "peak" and minimal improvements continue. After maturation (and ideally during maturation) continual stress and progressive overload yields improvement (overload principle). The progressive overload principle is often applied to volume in swimming, an aspect of overload, but a potential burnout pitfall. Overload has a wider spectrum, ranging from volume to biomechanics to psychology. Thomas Delorme developed this principle while rehabilitating soldiers in World War II  and is defined as (Kraemer 2007):

"the gradual increase of stress placed upon the body during exercise training."

Now, many elite swimmers show excellent skill acquisition and the unrelenting desire for improvement. This desire is sometimes present in young athletes resulting in coaches pushing these swimmers to burnout. Early specialization rarely works in sport and swimming isn't different [see Guide to LTAD in Swimmers].  

Instead, fostering an environment focusing on skill acquisition while applying progressive overload is essential. Yet, creating this environment is exhausting, but essential for the elite and ultra elite. Swimming provides it's difficulties for progressive overload, but also provides many possible variables. Think of all the methods possible for challenging a swimmer during a workout: times, stroke counts, tempos, biomechanics, etc. Challenging an elite athlete on one of these variables helps them focus feeds their desire of improvement. However, finding the balance of pushing the swimmer, but not knocking them over is part of the art of coaching. 

This is essential for gifted students/athletes of any field. Think no further than Michael Phelps the most successful Olympian and from our sport. During training, Coach Bowman continually challenged him. Now, this didn't and doesn't mean every aspect of training for Michael was recorded and stressed, but progressive overload was applied. Once again, pushing them, but not knocking them over is key. 

Michael was continually challenged during all periods of training. I have heard countless stories of fellow swimmers (often considered co-coaches in elite programs as peers provide vital feedback) giving Phelps challenges during sets.  In these stories, Phelps' teammate report him making unbelievable intervals during workout! It is these stories of being pushed and achieving success which create psychological and physiological overload and improvement for the ultra elite. 

If you coach one of these swimmers, apply purposeful, monitored progressive overload closely. If this swimmer hasn't reached maturity keep their success and potential in mind, as the most up-to-date research suggest early specialization impairs long-term success. However, if you have a pubescent swimmer ~14-years-old with these characteristics, apply this progressive overload, focusing on their weaknesses during their races. Remember, push them, but don't knock them over! 

  1. Kraemer, WJ, Fleck SJ. Optimizing Strength Training. Champaign, IL: Human Kinetics, 2007.
  2. Sweetenham B. ASCA Swimming Newsletter. 2013.
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.

Genes and Swimming Performance

Take Home Points on Genes and Swimming Performance

  1. Genetics likely contribute for swimming success, but are individualized to your ethnicity and distance specialty.
  2. Swimmers appear more reliant on ACE I/D, than the ACTN3 gene.

This is an excerpt from the March Swimming Science Research Review which is released on Friday March 15th. 

Make sure you pick your copy up today to enhance your swimming and evidence-based coaching.  


Genes and Swimming Performance

By now, everyone has heard of the 10,000 hour rule, a term coined from Dr.Ericsson's famous research and popularized by Gladwell. Unfortunately, this is mainstream view of genes and their involvement in sport (or any other area) is too simple. Dr. Tiago Barbosa broke down the guide to LTAD in swimmers, noting the role of genes for success. Genes play a role in athletic performance. The Sports Gene, a novel by David Epstein, discusses the influence of genes and performance.  Epstein's piece also questions the research by highlighting what is still unknown (see his interview on Sports Coach Radio). Genes play a role in sports, but the role for each person and for each sport is likely individual. 

Research on Genes and Swimming

Wang (2013) had two elite swimmer cohorts, comprising of Caucasian and East Asian subjects were analyzed. A total of 200 elite Caucasian swimmers (from Europe, American, and Russia) were sampled from 2005 – 2006 and categorized as short distance (less than 400 m; n=130) or long distance (less than 400 m; n=70). There were 116 male and 84 female Caucasian participants. East Asians comprised of short distance (less than 100 m; n=166) and middle distance (200 – 400 m; n=160). Females made up 130 subjects while the men made up 196 for the East Asian group. The East Asian group used Taiwanese and Japanese swimmers.

All the subjects underwent DNA sequencing and allele discriminatory testing.

Which Genes Improve Swimming Performance

The results suggested ACE I/D polymorphism is associated with elite swimmer status in both Caucasians and East Asians. The association is not seen in the longer-distance events in each group, but only in sprint middle distance swimmers in Caucasians and sprint distance swimmers in East Asians. ACTN3 p.R577X genotype was not significantly associated with swimmer status in these samples (unlike previous work in soccer players discussed in ACTN3 and Swimming Performance). In Caucasians ACE D allele was associated with elite status, versus the I allele in the East Asians. 

The varying allele association with success highlights some confusion, yet it may simply be that the sprinters are different than the middle distance swimmers or that different ethnicities have had different genetic alterations over the years. 

Also, the lack of ACTN3 association with success is surprising, as other sports demonstrate the ACTN3 is associated with greater power. This suggests swimming doesn’t rely on such power and perhaps relies more on biomechanics. Yet, there is contradictory evidence on ACTN3 and performance. Also, the classification of each swimmer's main activities is one limitation of this piece, since 50-m swimmers may have completely different genomes for success than 100-m swimmers (this applies to 200 and 400-m as well).

Practical Implication on Genes and Swimming Performance

Table of Contents March Swimming Science Research Review

  1. Perceived Effort Differs between Swimmers and Coaches | TRAINING
  2. Active Cool Down Decreases Lactate | RECOVERY
  3. Paddles Alter Swimming Force Production | PADDLES
  4. Individualization of Swim Suits | SWIM SUITS
  5. Force Asymmetry in Swimmers | BIOMECHANICS
  6. Swimming Minimally Increases Oxidative Stress | PHYSIOLOGY
  7. Snorkel Use Alters Breast Biomechanics | BIOMECHANICS
  8. Sex Differences in Swimmers | SWIMMING PERFORMANCE
  9. Genes and Performance | GENETICS
  10. Morning Practice Impairs Sleep | MORNING PRACTICE
  11. Different Pool Lengths Influence Performance | POOL LENGTH
  12. Salivary Proteins and Swimming Training | OVERTRAINING
  13. Peripheral Fatigue Limits Endurance | FATIGUE
  14. Bench Press Impairs Endurance Performance | TRAINING
  15. Fatigue and Thermal Stress | FATIGUE
  16. Comparing 400-m swim and 1500-m Run | SWIMMING PERFORMANCE
  17. Time-Trial Performance | TIME TRIALS
  18. Trends in Recreational Swimmers | LAP SWIMMING
  19. Practice Racing Breathing Strategies | BREATH TRAINING
  20. Oxygen Update in Swimmers | OXYGEN UPTAKE
  21. Decline in Performance with Age| PERFORMANCE
  22. Validating VO2max in nonexpert adults | MAXIMUM OXYGEN UPTAKE

Also, if you're interested in receiving updates on training and the abstract of the SSRR, don't forget to sign-up for our newsletter!
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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.
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2013 Recap!

What an exciting year in the world of swimming! Here are the five most popular articles from the past year, based on traffic volume at Swimming Science

  1. Dry-land Mistake: CrossFit for Swimmers - This article sure hit fire and grabbed a lot of attention (I was even ordered to remove an image...) from both sides of the argument. The use of CrossFit (or any dry-land program) must be analyzed thoroughly before implementation. Luckily, more research is coming out on CrossFit, stay tuned for a part II...
  2. Long Course vs. Short Course Swimming - Allan Phillips breaks down the main differences between short and long course training, bringing to light some considerations for training. 
  3. Does Extra Sleep Enhance Swimming Performance? - New comer to the website Herbie Behm posses this great question for a community engulfed in the tradition of sleep deprivation.
  4. Why Swimming Increases Low Back Degeneration - This recent article discusses why swimming increases low back degeneration. However, low back degeneration didn't increase injury rate and the sample was small, so more research is mandatory!
  5. How to Swim the Butterfly - This detailed post was inspired by Dr. Rushall and his breakdown of stroke biomechanics. Check out these tips on butterfly!

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Brief Swimming Review Volume 1 Edition 8

In an attempt to improve swimming transparency, a brief swimming related literature review will be posted on Saturday. If you enjoy this brief swimming review, consider supporting and purchasing the Swimming Science Research Review

Measuring Active Drag in Swimmers

Measuring drag is essential for quantifying biomechanical performance. Unfortunately, it seems there are large differences between active drag measurement systems as active drag (MAD) system and the assisted towing method (ATM) were compared (Formosa 2012).

"The mean active drag was 82.3 N (74.0-90.6 N) for the MAD system and 148.3 N (127.5-169.1 N) for the ATM system (Formosa 2012)". 

It seems the MAD system forces swimmers to use a different technique, compared to the free swimming ATM protocol. Unfortunately, the ATM forces a fixed swimming speed, far different than the natural self-selected speed.

Overall, it seems measuring active drag in swimming is still far from perfect, since both of these methods have flaws. 

Further Reading

Active Drag

Body Composition in Female Division 1 Athletes
Stanforth (2013) from the University of Texas analyzed the changes in body composition in female collegiate athletes (from basketball, soccer, swimming, volleyball, and track) over three years. The researchers used DXA analysis pre- and post-season for all three years. 

"Changes over three years included the following: Lean mass increased in VB from year 1 to 2 (0.7 kg), year 2 to 3 (1.1 kg) and year 1 to 3 (1.8 kg) and in SW from year 1 to 3 (0.6 kg); and %BF increased in BB from year 1 to 3 (1.7%). There were no changes in SOC or TR. These results indicate that during their college careers, female collegiate athletes can be expected to maintain their %BF and athletes in sports like SW and VB can anticipate an increase in lean mass, but the increases may be less than many athletes, coaches and trainers envision (Stanforth 2013)."

These results indicate body composition minimally changes in college despite large financial contributsions to strength and conditioning and nutrition. Now, I know strength and conditioning coaches do [should] much more than simply alter body composition, but a 0.6 kg difference over three years is far less than many would speculate. 

Do Bodyweight and Body Composition Affect Swim Performance 

  1. Formosa DP, Toussaint HM, Mason BR, Burkett B. Comparative analysis of active drag using the MAD system and an assisted towing method in front crawl swimming. J Appl Biomech. 2012 Dec;28(6):746-50. Epub 2012 May 9.
  2. Stanforth PR, Crim BN, Stanforth D, Stults-Kolehmainen MA. Body composition among female NCAA Division I athletes across the competitive season and over a multi-year time frame. J Strength Cond Res. 2013 Jul 15. [Epub ahead of print]
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 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.

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).

Friday Interview Dr. Gaël Guilhem Ph. D. Discusses Cryotherapy

1. Please introduce yourself to the readers (how you started in the profession, education, credentials, experience, etc.).
My name is Gaël Guilhem. I received my Master degree in 2006 in biology and physiology from the University of Paris V, and my PhD degree in 2010 in Sport Sciences from the University of Nantes, France. I currently work as a researcher at the French National Institute for Sports (INSEP), in Paris, since 2009. My major research interests focus on neuromuscular adaptations to acute and chronic exercise based on surface electromyography, ultrasonography, myostimulation and muscle damages markers. In parallel to my academic experience, I play ice hockey since I am 4, from the 2nd Division level to the Magnus League and I will play for Paris next season. My sport has gradually led me to get interested in biomechanical and neuromuscular determinants of high-level performance, and the innovative means to improve training or recovery.

2. You recently published an article on cryothereapy and neuromuscular recovery. Could you please explain cryotherapy and the physiology behind its potential benefits?
It is well-known that intense or unaccustomed eccentric exercise causes a deterioration of the activated muscle (exercise-induced muscle-damage). These alterations are associated with a loss of muscle force, a rise in muscle stiffness, inflammation, a delayed fluid accumulation around the initial site of trauma (edema) and muscular soreness. Besides its analgesic effect, the application of cold (cryotherapy) has been shown to reduce edema formation, decrease cell metabolism and consequently allow the uninjured cells neighboring the damaged fibers to survive the period of hypoxia induced by edema, after muscle damage. In other words, cryotherapy has been proposed as an effective means to enhance neuromuscular recovery after a damaging exercise. Exploring this, many authors have investigated the effect of localized (ice, cold water immersion) or global (whole body cryostimulation) cooling on symptoms associated with exercise-induced muscle damage. While some studies reported beneficial effects of cold on muscle strength, swelling, perceived soreness or exercise-induced edema, others did not show any significant effect on muscle recovery.

3. What were the main findings of your study?
We performed a randomized control trial study, which aimed to determine the effects of a new treatment, localized air-pulsed cryotherapy (-30°C), on the recovery time-course of neuromuscular function following a strenuous eccentric exercise, in comparison to a control group (without cold application).

Our results showed that few indicators of muscle damage after severe eccentric exercise were delayed (i.e., local formation of edema and decrease of muscle activity) by repeated air-pulsed cryotherapy (-30°C). However, we provide evidence that this cooling procedure failed to improve long-term recovery of muscle performance. Indeed, four applications of air-pulsed cryotherapy in the three days following a strenuous eccentric exercise were overall ineffective to promote the long-term muscle recovery process. Although cold application has been previously proposed to reduce some short-term consequences of muscle damage, our study thus failed to show clear benefits of repeated air-pulsed cryotherapy treatment on neuromuscular recovery after eccentric exercise. We also observed a large variability in the strength loss and symptoms of muscle damage between individuals in response to the same eccentric exercise protocol, as reported in previous studies. Hence, further studies are needed to take into account the amount of damage and to better quantify the mechanical stress (eccentric loading) that could be bound to its consequences on muscle performance. This will help to strongly conclude regarding the relative inefficacity of this recovery modality.

4. A lot of athletes use ice after strenuous exercise to reduce inflammation, do you think reducing infalmmation after exercise is beneficial for long-term performance?
This is a crucial question, which it is still difficult to answer, considering that most of the available studies investigated the acute effects of cooling on performance. Inflammation is essential in the recovery process, given that it contributes to cellular repair and regeneration of the biological tissues that could be affected by exercise (muscle, tendon, etc.). First, even if several studies, including ours, demonstrated a reduced inflammatory response after exercise, it is not sure that this will improve performance or accelerate the recovery process (as it was shown in our study). Second, and more importantly, little is known about the chronic impact of cooling use on muscle, tendon or ligament tissues (strength, mechanical properties, longevity) on performance. This is an open way of research in the next years.

5. How do you think athletes should use cryotherapy to their benefit?
What we should keep in mind is that most of the studies have demonstrated that cold application reduces perceived soreness. These findings thus suggest that if you feel less sore with cooling, you will be able to keep a higher level of performance than without cooling. However, it is not sure that your muscles will be “really” stronger. We effectively observed that the elbow flexor muscles of control and cryotherapy participants exhibit very similar physiological status from many points of view throughout the recovery time-course, until 14 days post-exercise. It is thus possible that the risk of injury will increase by maintaining an exercise or training load that you are actually unable to support, by using cooling. Therefore, and given our recent results, I firstly suggest the athletes to use cryotherapy for low amount of muscle damage (after a common strength training session for example) to reduce their perceived soreness, which could contribute to improve their comfort and well-being.

6. What are the biggest mistakes you see with cryotherapy?
I do not think that cold application must be use to facilitate the ability of the athletes to repeat an effort, particularly after intense, unaccustomed or long efforts. They can generate important muscular alterations which could not be amended by cryotherapy. In this context, reducing the pain sensation induced by exercise will thus increase the risk of musculo-articular injury.

7. How about painful high level athletes?
What we can see here in the INSEP, is that physiotherapists often use cryotherapy to relieve pain at joint or tendon level. Air-pulsed cooling is adequate and easy to use in this context.

8. Do you feel the spine has a specific amount of flexion cycles?
I regret I do not feel qualified to answer these questions.

9. Who is doing the most interesting research on cryotherapy? What are they doing?
Many research groups are interested in recovery processes, particularly cold application. Chris Bleakley and Joseph Costello are greatly involved in research projects designed to better understand the effects of cold water immersion and cryotherapy in general on post-exercise recovery. The Research Department of the INSEP also works since few years on recovery for performance, and leads several studies dealing with whole-body cryotherapy. These works resulted in the publication of a book entitled “Recovery for performance in sports”, written by researchers, physiotherapists, clinicians and practitioners, coordinated by Dr Christophe Hausswirth and Dr Inigo Mujika. Dr Costello also participates in a scientific collaboration with my colleague Dr. François Bieuzen. They further explore the potential hemodynamic factors that could be responsible for post-exercise recovery improvements with water immersion.

10. What makes your research different from others?
The potential originality of our study is the multi-approach method that we used. Indeed, most of the previous studies investigated some of the indicators of damage without considering the entire factors that could be affected by cold application. Moreover, most of the time, the considered recovery period do not exceed a few days. By measuring muscle strength, muscle activity, perceived soreness, edema and damage markers, we were able to accurately identify the physiological status of the muscle throughout a long recovery period (14 days). This project thus constituted a challenge, given the numerous procedures and parameters that were quantified on 24 participants, which participated in 6 test sessions. Indeed, 4-5 months were necessary to complete the experimental protocol only. From a technical point of view, it was also very interesting to measure the skin temperature decrease during cryotherapy intervention to accurately describe the treatment. In future studies we would like to assess the intra-muscular temperature which is more reflective of the actual cooling treatment than skin temperature.

11. Which teachers have most influenced your research?
I must say that I am always impressed when I read the last paper from Pr. Jacques Duchateau (University of Brussels), which has participated in my PhD jury. His very clever and simple researches have outstandingly contribute to improve the knowledge of the neuromuscular function and particularly the way it adapts to different form of resistance training. I follow with a great interest the huge work of Pr. Roger Enoka, Pr. Dario Farina, Pr. Walter Herzog and others. I am also very interested in the researches performed on muscle-tendon function in the University of Queensland, in Australia. My master degree director, François Hug, has always been an example to follow, and I have the chance to be surrounded by brilliant colleagues and collaborators in Paris and Nantes.

12. What research or projects are you currently working on or should we look from you in the future?
Currently, I pursue my main research topics dealing with the effects of different resistance modalities on neuromuscular function. A few studies are engaged to test the reliability of new ergometers or methods used to evaluate muscle abilities. Longitudinal studies are also planned to determine the effect of innovative strength training modalities. As we are working with many Olympic sports in the INSEP, we are also working with national teams to identify the needs and constraints associated with their sport activity. In this context, we help coaches to evaluate the physical profile of their athletes and to optimize their training contents or recovery procedures, as it is performed in many countries today.

I would like to thank Dr.. Mullen for his interest and the readers of swimmingscience.net. Best wishes from Paris.

Competitive Swimming and Dental Health

Competitive swimming brings many hazards despite outward appearances of cardiovasuclar health and muscular fitness.  What TV cameras don’t show is the omnipresent dry skin, disintegrated hair, funky tans, and chronic chlorine body odor….Another hazard of swimming is dental health.  Chlorine and other cleansing agents are placed into pools for a reason…to keep the pool clean.  Unfortunately, chlorine doesn’t discriminate between “good” and “bad” targets.  As a result, the teeth are among the body parts that often take a beating from long term exposure to pool chemicals.  

One recent study (Baghele 2013) offered rather morbid statistics on dental health in a sample of 100 teenage competitive swimmers in India.  Authors conducted dental exams and found that “90% showed dental erosion, 94% exhibited rough surfaces, and 88% were found to be having tooth pain of varying severity. Erosion and rough surfaces were found to be directly proportional to the duration of swimming.” 
Now, obviously not all pools are created equal, as some are chemical soup bowls while others seem almost drinkable.  In isolation, you might discard this research as being from an unknown pool on the other side of the world with no control group.  But unfortunately, this evidence is not a complete outlier in the literature…   

Buczkowska-Radlińska (2013) studied junior and senior level competitive swimmers and compared them with recreational swimmers. 
“Dental erosion was found in more than 26 % of the competitive swimmers and 10 % of the recreational swimmers. The lesions in competitive swimmers were on both the labial and palatal surfaces of the anterior teeth, whereas erosions in recreational swimmers developed exclusively on the palatal surfaces.”   Regarding pool conditions, authors noted that “Although the pH of the pool water was neutral, it was undersaturated with respect to hydroxyapatite.”
Another study from Poland (Kaczmarek 2010) also studied competitive swimmers (16-25 hours per week in the pool) and compared them with a control group of recreational swimmers and nonswimmers.  “Dental lesions in the form of erosions were more common in competitive swimmers than in the control group.  Dental erosions were located mainly on the labial surfaces of maxillary incisors.”  Despite the prevalence of erosion in the competitive swimmers, there was no difference in cavities in either population. 

Speaking of cavities, another issue of concern in swimming is the potential effect from energy drinks.  Because athletes typically consume more energy drinks than nonathletes, it is theorized that athletes may be at higher risk.  If the risk is real, we might suspect that swimmer could be at higher risk due to lengthier practices compared other sports.  Is this link real or imagined?
Coombes (2005) completed a review study and noted, “There is no doubt that the acidic nature of sports drinks has the potential to cause dental erosion….  Two case control studies have reported contradictory findings on the association between sports drink consumption and dental erosion and the three cross sectional studies in athletes have all failed to find a relationship. Combined, these studies indicate that isolating one dietary component as causative of erosion may be simplistic and factors such as drinking habit and salivary production may play a more influential role on the pathology.”
Practical Implications
Despite the inconclusive evidence on sports drinks and dental health, Coombes concludes, “[O]ral health educators should be reinforcing important practices to sports drink users such as decreasing the time that the sports drink remains in the mouth and avoiding dehydration.”  In short, though evidence remains inconclusive, swimmers should remain aware how long the drink stays in their mouths.  But fortunately, dry mouth is rarely a concern for swimmers while in the pool! 
As to the erosive potential from the pool itself, coaches and swimmers may not have control over pool conditions, but parents and swimmers should be proactive about managing side effects.  Though making specific dental recommendations is likely outside our practice areas on this site, awareness remains an important key for long term management. 

  1. Baghele O, Majumdar I, Thorat M, Nawar R, Om Baghele M, Makkad S.  Prevalence of Dental Erosion Among Young Competitive Swimmers: A Pilot Study.  Compend Contin Educ Dent. 2013 Feb;34(2):E20-E24.
  2. Buczkowska-Radlińska J, Łagocka R, Kaczmarek W, Górski M, Nowicka A.  Prevalence of dental erosion in adolescent competitive swimmers exposed to gas-chlorinated swimming pool water.  Clin Oral Investig. 2013 Mar;17(2):579-83. doi: 10.1007/s00784-012-0720-6. Epub 2012 Apr 3.
  3. Kaczmarek W. [The status of mineralized dental tissues in young competitive swimmers].  Ann Acad Med Stetin. 2010;56(3):81-6.
  4. Coombes, J.  Sports Drinks and Dental.  Am J Dent 2005;18:101-104.
By Allan Phillips. Allan and his wife Katherine are heavily involved in the strength and conditioning community, for more information refer to Pike Athletics.

Exhaustive Resistance Training Alters Joint Biomechanics

"Although no research consistently suggests resistance training directly improves swimming, if certain goals are kept in mind, it is likely a mode to benefit swimming performance. Also, if you do decide to lift, swimming prior to resistance training is likely most beneficial to allow maximal performance at swim practice and potentially stress the body more at dry-land to yield greater results (Mullen 2012)". 

Despite this recommendation, as more research surmounts, further updates are warranted. Luckily, a recent study analyzed the effects of resistance training fatigue on joint biomechanics. Hooper (2013) and researchers from Connecticut had twelve trained male subjects (mean age 24) perform an exhaustive resistance exercise program consisting of:

“75% 1RM was used on each of the 3 lifts; back squat, bench press, and deadlift. The subjects began with 10 repetitions of each lift and then reduced the number consecutively by 1 until they reached only 1 repetition (Hooper 2013)”.

After the fatiguing resistance training protocol, hip and knee kinematics were measured with a body weight squat. The results indicated significant alterations in hip and knee kinematics. These results suggest kinematic alterations do occur after fatiguing resistance training.

Looks like someone lifted heavy before swimming...
One asset of the internet is the ability to instantly update information and alter recommendations when warranted. Overall, the swimming community must improve their ability to obtain information and adjust training practices (if you're reading this site, then you'll love the Swimming Science Research Review). This study adds confirmation to the suggestion noted back in December, as

"[m]ovement alterations secondary to resistance training is not ground-breaking information, but it does suggest resistance training prior to swimming may alter joint kinematics. Future studies must confirm this and see how long the kinematic adaptations occur after resistance training (Mullen 2013)".

Once again, if you are performing exhaustive resistance training (ie CrossFit ... which requires a separate post), then perform resistance training after exercise. This does not suggest all resistance training must be done after swimming, as post-activation potentiation (PAP) may improve short-term power output (see tomorrow's interview with Dr. Fletcher). Moreover, different resistance training intensities must be tested to affirm results with different intensity or dry-land activates.

  1. Hooper DR, Szivak TK, Distefano LJ, Comstock BA, Dunn-Lewis C, Apicella JM, Kelly NA, Creighton BC, Volek JS, Maresh CM, Kraemer WJ. Effects of resistance training fatigue on joint biomechanics.J Strength Cond Res. 2013 Jan;27(1):146-53. 
  2. Mullen, GJ. (2012). Should I lift Before or After I swim. Swimming Science. Retrieved Feb. 27, 2013, http://www.swimmingscience.net/2012/12/should-i-lift-before-or-after-i-swim.html.
By G. John Mullen Doctorate of Physical Therapy founder of the Center of Optimal Restoration, Dochead strength coach at Santa Clara Swim Club, creator of the Swimmer's Shoulder System, and chief editor of the Swimming Science Research Review.

Immune System and Elite Swimmers: Part II

After last week's post on Immune System and Elite Swimmers, one of our readers posted an excellent question:

I understand that this gives you ideas of how to spot the likelihood of the upper respiratory infections, but what suggestions exist for minimizing or eliminating them? Is there a dietary or vitamin plan?

First things first: Many illnesses are within our control even if they seem like random luck.  Yes, there are cases in which you do everything right and you turn up with a cold at the wrong time, just as there are other outliers who take poor care of their bodies but avoid immune system setbacks.  But if you challenge the organism when it’s in a depressed state (regardless of WHY it’s in that state), the body is more vulnerable to immune system setbacks .  Revisit what you are doing in the water; otherwise special meal plans and supplements are just figurative band-aids for immunity problems caused by ineffective training and deficient diets. 

Monitoring is also important.  Several weeks ago we addressed ways to assess autonomic nervous system readiness.  We don’t know if the body is vulnerable unless we actually check its state daily.  If you don’t assess, it’s just a guess!    

Building the immune system is like a cyclist learning to handle a bike.  You always wear a helmet on the bike, but you must learn to learn how to avoid crashes and not need your helmet.  Search for any deficiencies first before choosing supplementation or modifying diet beyond normal athlete recommendations.  Once we establish that our training is not causing any more stress than necessary for adaption, we can explore ways to fortify the immune system.  But as with training, it’s most important to identify deficits first.  
"Ensuring adequate energy, carbohydrate and protein intake and avoiding deficiencies of micronutrients are key to maintaining immune health." (Walls 2011)

In one recent study, Mestre-Alfaro (2011) studied the effect of phytoestrogen supplementation in female swimmers.  A control group received a supplement with vitamins C and E, while the experimental group received the same beverage but also with phytoestrogens.  The experimental group had significant improvements in enzyme activity for lymphocytes and erythrocytes after exercise, indicating improved immune response.  Phytoestrogens are not female-specific but can be obtained naturally through legumes, whole grain cereals, flax, various seeds, and even bourbon, among several other sources.

Although not swim specific, Walsh (2011) notes that nutritional supplements including flavonoids such as quercetin and Lactobacillus probiotics can augment some aspects of immune function and reduce illness rates in exercise-stressed athletes Quercerin-rich foods include: Black and green teas, apples, onions, red grapes, leafy green vegetables, and several berry types.  Lactobacilus probiotic food sources include yogurt, dark chocolate, pickles, miso soup, and tempeh.  Walsh (2011) also notes that “Limited data are non-supportive or mixed for use of N-3 polyunsaturated fatty acids, beta-glucans, bovine colostrums, ginseng, echinacea or megadoses of vitamin C by athletes.” 

Vitamin C is commonly recommended for immunity, but as noted, the evidence on vitamin C and the immune system is mixed.  In swimming, Constantini (2011) studied the effect of vitamin C on upper respiratory tract infections in male and female adolescent swimmers but found that only males improved immunity.  However, authors specificalluy called for additional study to confirm or deny these conclusions. 

Interestingly, vitamin C may indirectly affect immunity as it is often linked to iron absorption.  Healthy iron levels can help swimmers absorb their training loads, making them less vulnerable to overtraining.  Although vitamin C has received mixed reviews in the literature, supplements combining vitamin C with other vitamins such as vitamin E have been shown to improve immunity in athlete populations (Tauler 2002, Sureda 2008)

Minerals also play a key role in immunity: Dragan (1990) studied thirty three top level male and female swimmers and found that selenium supplementation improved blood markers for immunity.  Brazil nuts, oysters, fish, and sunflower seeds are among the top sources for selenium.

Ensure your swimmers are training appropriately and meeting basic nutrition needs before worrying about supplementation.  Nevertheless, know that robust evidence supports adding flavonoids, phytoestrogens, and selenium to the diet specifically to improve immunity among athletes.


  1. Constantini NWDubnov-Raz GEyal BBBerry EMCohen AHHemilä H.  The effect of vitamin C on upper respiratory infections in adolescent swimmers: a randomized trial.  Eur J Pediatr. 2011 Jan;170(1):59-63. Epub 2010 Aug 6.
  2. Walsh NPGleeson MPyne DBNieman DCDhabhar FSShephard RJOliver SJBermon SKajeniene A.  Position statement. Part two: Maintaining immune health.  Exerc Immunol Rev. 2011;17:64-103.
  3. Drăgan IDinu VMohora MCristea EPloeşteanu EStroescu V.  Studies regarding the antioxidant effects of selenium on top swimmers.  Rev Roum Physiol. 1990 Jan-Mar;27(1):15-20.
  4. Tauler PAguiló AFuentespina ETur JAPons A. Diet supplementation with vitamin E, vitamin C and beta-carotene cocktail enhances basal neutrophil antioxidant enzymes in athletes.  Pflugers Arch. 2002 Mar;443(5-6):791-7.
  5. Sureda ATauler PAguiló ACases NLlompart ITur JAPons A.  Influence of an antioxidant vitamin-enriched drink on pre- and post-exercise lymphocyte antioxidantsystem.  Ann Nutr Metab. 2008;52(3):233-40. Epub 2008 Jun 19.
  6. Mestre-Alfaro AFerrer MDSureda ATauler PMartínez EBibiloni MMMicol VTur JAPons A.  Phytoestrogens enhance antioxidant enzymes after swimming exercise and modulate sex hormoneplasma levels in female swimmers.  Eur J Appl Physiol. 2011 Sep;111(9):2281-94. Epub 2011 Feb 18.
By Allan Phillips. Allan and his wife Katherine are heavily involved in the strength and conditioning community, for more information refer to Pike Athletics.