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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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Ovarian Suppression in Elite Athletes

Take Home Points:

  1. A regular menstrual cycle is beneficial for swimmers.
  2. A regular menstrual cycle promotes a positive energy balance and higher performance.

Energy balance (EB) is maintained in swimmers by maintaining adequate energy reserves via energy intake (EI) and exercise energy expenditure (EEE) with training loads. As training intensity and duration increase within a season so do the requirements for resting energy expenditure (REE) and energy availability (EA). Female athletes have been found to be unsuccessful in maintaining EB, leading to nutrition repartitioning within their body leading to energy conservation. Medical symptoms can present in these female athletes including impaired menses, bone, and cardiovascular health. Estradiol (E2), progesterone (P4), and total triiodothyronine (TT3) concentrations have been associated with the above medical findings. The focus of this study was to explore the influences these ovarian hormones have on sports performance in female swimmers.

To assess the impact of suppressed ovarian hormones secondary to an energy deficit, research assessed 400m times over a 12-week competitive swimming season in junior national caliber athletes. 10 female swimmers (age 15-17 yrs.) participated in the study beginning at the onset of the training season and ending at the final major competition 12 weeks later. The athletes were evaluated every 2 weeks; determining ovarian hormones (E2 and P4), TT3, IGF-1, REE, EEE, EI, EA, body composition, and 400m swim velocity. In addition, a daily diary was kept to track sleep, diet, injury, illness, stressors, and menstrual cycle.

Ovarian Suprresion

Athletes classified as ovarian suppressed (OVS) or cyclic menstrual function (CYC) based upon the first two week E2 and P4 levels as well as menstrual status from daily log. Each group had 5 participants who were similar in chronological and gynecological age. Training characteristics was similar between groups, training 13.5 hours a week of pool time with 1.6 hours a week of dryland training. The swimmers preseason times and dietary intake were similar between groups but the CYC group did intake more than their OVS counterparts during the season.

(CYC) swimmers with normal menstrual cycle after week 12
  • Lower BMI, 20±0.4kgm-2
  • Lower Fat Mass,10.6+3.0kg
  • Decline in times at midseason, 10%
  • Improved performance at week 12, 8.2%
  • Normal (eumenorrheic) menstrual cycles of 18-31d at baseline
    • 26-33d at week 12
(OVS) swimmers with abnormal menstrual cycle after week 12
  • Suppressed pattern in E2, P4,TT3, and EA
  • Higher BMI, 24±1.0kgm-2
  • Greater fat mass, 14.4+2.3kg
  • Decline in times at midseason, 12%
  • Decline in postseason times, 9.8%
  • Abnormal (oligomenorrheic) menstrual cycle at baseline, 33-46d
  • Abnormal at week 12, >36d

Ovarian Suppression Decreases Sports Performance

This study found a decrease in elite athlete sports performance with chronic ovarian suppression secondary to an energy deficit. No swimmers were found to be absent of their menses, amenorrhea. During the study, the OVS group failed to menstruate after the first 2 weeks training. An amenorrhea criterion is cessation of menses for 90d or more, which the length of the study failed to determine.

What to do with Ovarian Suppression?

A healthy menstrual cycle is beneficial to swimmers and is influenced by many things including diet, sleep, stress, training or overtraining. This study supports swimmers who can maintain a healthy menstrual cycle will have improved energy balance (EB) and performance compared to their teammates who have an impaired cycle. It is unknown from this study how the volume of training and performance affects yearlong swimmers as this study looked at a 3-month period of training. However, this research supports a coaching strategy that does not promote energy restrictive practices as improved performance can be detrimentally affected by a hormonally suppressed internal environment.

  1. Vanheest JL, Rodgers CD, Mahoney CE, De Souza MJ. Ovarian suppression impairs sport performance in junior elite female swimmers. Med Sci Sports Exerc. 2014 Jan;46(1):156-66. doi: 10.1249/MSS.0b013e3182a32b72. PubMed PMID: 23846160
The Swimming Science Research Review educates coaches with ongoing sports science literature. With 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.

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.

Race Analysis and Video: Katie Ledecky 400 Free World Record

Take Home Points on Race Analysis and Video: Katie Ledecky 400 Free World Record
  • Katie Ledecky broke the 400, 800 and 1500m freestyle world records in roughly one and a half month, being the first American swimmer holding the big-three middle- and long-distance records after Janet Evans.
  • She swam the 1500m at a 1:02 pace, the 800m in negative split and the 400m with two splits bellow one minute.
  • There is a trend for the number of strokes per lap decrease with increasing distance (1500m: first half 38 and second half 39-40; 800m: 40-41; 400m: first half 39 and second half 40-41).
A good piece of news is when a man bites the dog. Katie Ledecky breaking another world
record is not a surprise or comes out of the blue. But to be the first woman after Janet Evans holding the 400, 800 and 1500m freestyle records, that is truly… remarkable. We are talking about three world records broken in roughly one and a half month, wearing textile swimsuits and still on the road to the season´s major competition. On top of that, she posted the 2nd best time in the world at the 200m event (as on 10 August 2014; table 1).

As you can imagine I did not have much time to carry a deep analysis. So, my purpose for today is to compare the split times and number of strokes per split in the four events. Split times were retrieved from the competitions´ websites. I will report both the 50m (figure 1) and 100m (main text) split times. The stroke count (number of strokes per 50m split) was done after downloading the videos from the web. Unfortunately for the 1500m event, I failed to find the full race. There is one video available that is a 7 minutes condensed version of the race from beginning to end. So, I had to interpolate some missing data (dash line in figure 2). If you wish the number of stroke cycles rather than the number of strokes, just divide the figures reported by two.

Regarding the split times (figure 1): (i) a very stable swim pace at the 1500m (around 1:02) and she end the race in 1:00.7; (ii) we can see clearly the negative split at the 800m event; (iii) in the 400m, two splits bellow one minute (57.74; 59.98) and remaining two inside the “double-0” (1:00.68; 1:00.46); (iv) in the shortest event, splits where 56.64 and 58.52, respectively. Probably several countries would like to have their top-sprinters doing these 200m splits.

The partial difference (table 2) of Ledecky´s split times in the 1500m in comparison with the: (i) 800m is between -0.44% and 3.89%; (ii) 400m, 3.05-4.20%; (iii) 200m, 5.60-6.80%. I.e. the first half of the 1500m and the 800m paces are fairly similar (on average a 0.40s difference per 100m split). In the last 100m of both races (i.e. 1400-1500m and 700-800m) she clocked 1:00.7 and 1:00.12 (difference: 0.58s).

Concerning to the stroke counts: (i) there is a trend for the number of strokes per lap decrease with increasing distance; (ii) number of strokes increases in the second half of the 1500m event from 38 to 39-40; (iii) in the 800m event the number of strokes was rather stable, between 40 and 41; (iv) in the 400m event, we can see again that the number of strokes increases in the second half from 39 to 40-41; (v) as expected the 200m is the race with the highest number of strokes per split (38-41); (vi) it might be interesting to pinpoint that Katie did 33, 34 and 35 strokes (first split) and 38, 38 and 29 strokes (second and third splits) in the 1500, 800 and 400m events, respectively.

My guess (my bet?) is that the figures I report here might be of no use by the end of the summer. After the Pan Pacs, to be held in late August, we may need to update this post. I hope you enjoyed the analysis though.

By Tiago M. Barbosa that earned a PhD degree in Sport Sciences and holds a faculty position at the Nanyang Technological University, Singapore.

3 Things you Didn't Know About Ultra-Endurance Swimming

Take Home Points on 3 Things you Didn't Know About Ultra-Endurance Swimming
  1. Ultra-endurance swimming often doesn't result in maximal fatigue, cause hunger, or alter swimming hand path.
  2. This form of training isn't as negative as some suggest on swimming skill.
Many associate ultra-endurance swimming with pain and fatigue. However, we know little
on the subject, despite it's growing popularity. Now, many swimmers have performed ultra-endurance swimming during practice through the forms of tests sets (Timed 30 minute swim or timed 3,000) and Allan Philips has discussed some of the risks/benefits of this training previously. Most swimmers would likely agree these sets are arduous times. For one, there is no break. Another difficulty is the pure mental strength required for the task. These are two reasons some coaches (for one Bob Bowman) enjoy these sets. Unfortunately, these are anecdotal reasons for this form of training. Scientifically, little is known on ultra-endurance swimming. Here are three misconceptions on ultra-endurance swimming.

  1. You Don't Reach Maximal Fatigue: Fatigue is multifactorial, associated with a decrease in muscle performance. Swimming fatigue is most noted with an increase in energy cost and a change in biomechanical stroke parameters. Despite the frequent discussion of physiological factors influencing fatigue, psychological factors are also thought to impair swimming. For example, when swimming for an extended period of time rating of perceived exertion (RPE) increases. Conscious information is the memory of the RPE of a familiar task. When an athlete is performing a novel exercise or distance, a conservative pacing approach is performed. This is why many can raise their effort level at the end of a task. The decision to cease the task would be mainly due to two psychological factors: the potential motivation and the perceived exertion. A recent study analyzed the effects of a 25-km time trial on national and international swimmers (not ultra-endurance swimmers) and found a significantly higher RPE, but not a maximal RPE during the swim. The reason for not reaching maximal RPE may be due to the novelty of the race for these swimmers (mostly sprinters) or the positive experience of finishing the task. Now, the results may be different with highly trained ultra-endurance swimmers, but for most swimmers you aren't even reaching maximal effort during ultra-endurance swimming! 
  2. You Don't Get Hungry! Hunger, like fatigue, is a complicated subject. One would expect a swimmer to become hungry during an ultra-endurance race due to the amount of calories burned. This high caloric expenditure creates a negative energy balance, yet during a 25-km swim, swimmers don't report hunger! The authors concluded "the reduction in leptin compensated for a negative energy balance due to the prolonged effort through an increase in appetite". Despite the lack of hunger, consuming some calories is paramount for ultra-endurance training. For example, if an ultra-endurance swimmer is not consuming calories they may lack in energy for maximal performance. The swimmers may also risk hyponatremia, low blood salt. Hyponatremia is a deadly condition, which kills a couple ultra-endurance runners each year. Now, the swimmers don't need to eat something, but could simply drink a fluid containing calories.  
  3. Hand Path Doesn't Change: Many coaches avoid ultra-endurance sets as they are adapting the principle of specificity. However, this study noted no change in the hand path of the swimmers during an ultra-endurance race. This doesn't imply they are using "race" specific biomechanics, but that they are locking into a pattern which isn't changing form. Since the hand path isn't changing one could argue this form of training isn't as negative as previously thought.
These three things you didn't know about ultra-endurance swimming are from one study, of non-ultra-endurance-swimmers. More research on trained ultra-endurance swimmers is warranted, as one would assume they can reach higher levels of fatigue during this racing.

If you are prescribing ultra-endurance training sets, keep this notions in mind, as safety and maximal performance are two main goals!

  1. Invernizzi PL, Limonta E, Bosio A, Scurati R, Veicsteinas A, Esposito F. Effects of a 25-km trial on psychological, physiological and stroke characteristics of short- and mid-distance swimmers. J Sports Med Phys Fitness. 2014 Feb;54(1):53-62.
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.

Are Ice and NSAIDs Beneficial for Recovery?

Take Home Points on Are Ice and NSAIDs Beneficial for Recovery?
  • Ice helps decrease pain, but does increase muscle damage.
  • NSAIDs restore function, but improve bone, but not soft tissue healing.
The use of non-steroid anti-inflammatory drugs (NSAIDs) and ice are common staples in
sports medicine. Yet, the use of these modalities has recently received resistance from some online experts (Kelly Starrett, Dr. Gabe Mirkin). Despite this criticism, these modalities are still frequently used, sometimes ad libium. Now, before I make a notion on these modalities, it is important to understand the injury process, below is an exert from the COR Swimmer's Shoulder System.

Everyone is familiar with inflammation. The inflammatory process occurs within seconds of every injury, but can linger for weeks or months with bad injuries or poor management.

Inflammation is stemmed by the infiltration of cells, entitled neutrophils, during the first 6-24 hours; they are replaced by other cells (monocytes) in 24-48 hours. These cells will try to attack the inflammation and remove injurious agents. Phagocytosis is involved in the process of engulfing foreign particles and releasing the enzymes of neutrophils and macrophages which are responsible for eliminating the injurious agents. These are two major benefits derived by the accumulation of leukocytes at the inflammatory site.

Chronic inflammation is a different warrior. The key player is another type of cell, the macrophage. Macrophages are large cells that can remain for weeks to months, perpetuating injuries.

The classic signs and symptoms of inflammation are swelling, redness, throbbing, radiating heat, and constant pain. These pains especially occur when you wake up in the morning and last between thirty and sixty minutes. Also, just because you had the initial injury four months ago doesn’t mean inflammation has resolved or hasn’t returned, so pay closer attention to the signs and symptoms as opposed to the duration.

Once again, the inflammtory process initiates every injury. This process is beneficial in restoring the body, but does decrease strength. This decrease in strength is why many seek improvement [well and the pain]. This has resulted in the use of the two most common modalities NSAIDs and ice. Unfortunately, these two modalities may prevent the normal physiological reaction of an injury. This impairment is thought to alter long-term improvement. However, many people take NSAIDs and ice for short-term gains. If someone needs improvement, for a quick return to the pool, then NSAIDs and ice are beneficial. However, the use of these modalities likely decreases long-term recovery, perhaps increasing the risk of re-injury. Unfortunately, most of this research is based on rodents, not humans and as I've mentioned before, rodents have different inflammatory processes! This makes the research nontransferable to humans ... oh well! Nonetheless, lets look at the research we have!

NSAIDs on Healing

The authors reviewed the effectiveness of NSAIDS and selective (COX-2 inhibitors) NSAIDS on soft tissue and bone healing. A total of 44 articles reviewed (9 on soft tissue and 35 on bone healing). Thirty-nine of these articles were on animals and 5 on humans.

No humans studies have been done on humans assessing the interaction between NSAIDS and soft tissue healing. Of the studies reviewed, there is a controversy between the administration of selective and non-selective NSAIDS after surgery, as many studies suggest detrimental effects on bone and soft tissue healing. However, the literature on this subject in humans is minimal.

It appears inflammation mediated by prostaglandins is necessary to improve bone healing. However, in soft tissue injury, growth factors are more important and prostaglandins less involved. This suggest NAIDS are likely beneficial in soft tissue, but potentially not bone healing.

Improving inflammation is necessary to decrease symptoms, however the use of NAIDS during bone repair may impair recovery, therefore only use NSAIDs in soft tissue injuries. However, more human clinical trials are necessary before a definitive answer is possible.

NSAIDs on Gut Bacteria

One potential hazardous result of NSAID consumption is the potential loss of integrity of bacteria, making the gut permeable to harmful substance.

Nine male trained cyclists underwent small intestine lining permeability in four different conditions (Van Wijck 2012):

1) during and after cycling after intake of ibuprofen

2) during and after cycling without ibuprofen

3) rest with prior intake of ibuprofen

4) rest with prior ibuprofen intake

The small intestinal lining was evaluated by providing the subjects a sugary drink, then assessing the amount of human intestinal fatty acid binding protein (I-FABP).

The ibuprofen conditions took 400 mg of ibuprofen the night before and 1-hour prior to cycling on a fasted stomach. The cyclist performed roughly 90 minutes of cycling at moderate/hard cycling.

In both exercise conditions, the I-FABP levels gradually increased with cycling. However, cycling with ibuprofen ingestion resulted in even high levels of I-FABP.

These results show cycling alone increases both gastroduodenal and small intestinal permeability. This difference increased with ibuprofen intake. This is thought to be from splanchic hypoperfusion, reducing the blood to the gut and including injury to the enterocytes. One of the major pathways suspected for GI damage is:

“to be involved is the inhibition of COX isotypes 1 and 2, resulting in local inflammation and vascular dysregulation, ultimately reducing perfusion and promoting mucosal integrity loss within the splanchnic area (Van Wijck 2012)”.

Unless ergogenic benefits from NSAIDs exists, swimmers should not use these medications prior to exercise. Moreover, inflammation may yield greater results in endurance sports. One flaw with the study is the fact the athletes were fasted while taking NSAIDs. However, one note is the athletes were fasted during this test, this may have increased the intestinal lining to susceptibility.

For rehabilitation, NSAIDs may still be beneficial, but at this time it is not certain if the benefits outweigh the risks.

Ice and Muscle Damage Healing

Eleven male college baseball players underwent two trials: sham application and topical cooling. Each trial was used five sessions of 15-min cold pack application to the exercised muscles 0 hours, 3 hours, 24 hours, 48 hours, and 72 hours after eccentric exercise training.

The eccentric training protocol consisted of 6 sets of 5 eccentric contractions with 2 min rest between sets at 85% of their maximal strength. Muscle hemodynamics (hemoglobin most notably), inflammatory cytokines (multiple interleukins), muscle damage markers (Creatine kinase), visual analog scale (VAS), and muscle isometric strength.

After topical cooling, rapid and sustained elevations in total hemoglobin and tissue oxygen saturation were noted. Also, creatine kinase was noted in both trials, but was elevated after topical cooling. Inflammatory markers were not changed following cooling. VAS was not different between groups, however topical cooling significantly increased rating of fatigue post-exercise. No significant differences were noted in strength between groups.

Increased muscle damage, most notably the creatine kinase increase, was apparent in the topical cooling group. This is thought to occur from the rapid deviation in blood supply to the muscle.

Using ice after practice improves muscular soreness, but appears to increase muscle damage due to rapid changes in ischemia. Therefore, unless injured topical cooling should be avoided.

Ice and Blood Flow

Nineteen subjects participated in this single-blinded, where the clinician was blinded. There was no history of lower extremity injuries for the past 6 injuries. Each participant visited the laboratory four separate times where baselines were measured at the first two visits, then the next two visits a trial of ice (750-g of crushed ice placed on the medial gastrocnemius) and a control trial.

“There was a significant correlation (r = 0.49) between subcutaneous tissue thickness and change in intramuscular temperature immediately after treatment (P = 0.05) for the cryotherapy condition. Significant correlations were also found for change in temperature during the rewarming period and change in blood volume at rewarming (r = 0.53, P = 0.033) and change in blood flow at rewarming (r = 0.56, P = 0.025) for cryotherapy (Selkow 2012)”.

Microvascular perfusion of the gastrocnemius did not decrease from baseline with cyrotherapy was applied, despite the decrease in subcutaneous temperature. The result was different than past studies, as many think cryotherapy decreases blood flow. This may be from no alterations noted in the microvascular.

In the healthy population, cryotherapy appears not to alter blood-flow. Therefore, benefits and risks associated with cryotherapy application for inflammation may be negligible. However, next research must look at inflammation specifically. Until then, the effects of ice for injuries seem purely for slowing nerve conduction to gate pain.

NSAIDs or Corticosteroids for Recovery

Zheng (2014) performed a systematic review of all the high-quality studies comparing NSAIDs and corticosteroid injections, a total of ten full articles. Overall, 267 patients were analyzed and of the six studies two focuses on rotator cuff tendonitis patients, two on shoulder impingement syndrome, one studied frozen shoulder of diabetes and the other investigated shoulder pain.

Of these studies, NSAIDs and corticosteroids did not have a significant difference in pain improvement. Corticosteroids were significantly better for remission of symptoms. Five of the studies reported range of active shoulder abduction and note NSAIDs did not significantly improve the active shoulder abduction compared to corticosteroids. The studies assessed were 4 – 6 weeks in length.

Compared to NSAIDs, corticosteroid injections provide faster relief. However, comparisons of other therapies and conjunctions of therapy are needed, as well as longer study periods and follow-ups.

My Recommendations

If you are injured, stop exercising. If the pain is non-stop, see a rehabilitation specialist like a physical therapist. At this time, apply ice, as it does reduce pain and doesn't seem to alter blood flow. However, apply the ice for a short period, as it may increase muscular damage. I suggest applying the ice for up to 10 minutes and remove it for 20 minutes. Only ice immediately after the injury, ~6 hours after the injury. If you are competing at a meet and must perform, NSAIDs can help decrease pain and restore function. However, if you are not in a rush for return, try not to ice and consider compression instead. Compression helps naturally clear the fluid from the joint, facilitating recovery. When you are able to move comfortably without pain, do so. Movement also helps move fluid out of the joint and restore function. However, do not move into pain, as this can alter movement patterns and impair function. 

Try and prevent using NSAIDs, unless unrelenting pain exists and the injury appears muscular. If recovering from an injury, a corticosteroid injection is likely better than just NSAIDs, but remember other rehabilitation is needed. 

We have much more research needed on the subject, but it isn't clear that ice and NSAIDs are a “no brainer”. Until more research is performed, I'll continue the suggestions I've made for years, if you're in no rush, let the inflammation naturally make it's way throughout the body, giving yourself rest and compression for improvement. Once you're able to move naturally do so! However, if you are in a rush, like at a big competition and need to get in the pool, NSAIDs and ice can help!


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.

Does Altitude Training Work for Swimming?: Part II

Take Home Points on Does Altitude Training Work for Swimming?: Part II
  1. Individuality is a key point in recent literature on altitude training.
  2. Altitude may change biological markers, but changes in race swim speed are uncertain.
  3. Despite the prevalence of individuality, individual response is not a fixed trait.
Altitude training is always a controversial topic in swimming and sports as a whole.  We
have covered this topic before, but it is worthwhile to review the recent literature to note recent updates.  Many teams have taken swimmers to altitude locations during the summer and are anticipating meaningful improvements at late summer long course meets. 

One key point in recent literature is how responses to altitude training are highly individual.  Though teams will often take an entire squad to an altitude site, swimmers under the same program may respond in highly varied ways to similar workouts.  Whereas certain athletes thrive on altitude, others may be overstressed just by the altitude exposure before factoring in training.  As Chapman writes (2013),

“some athletes are clearly more negatively affected during exercise in hypoxia than other athletes. With careful screening, it may be possible to develop a protocol for determining which athletes may be the most negatively affected during competition and/or training at altitude.”

Screening protocols may be effective but altitude responsiveness is a moving target.  McLean (2013) studied elite footballers in 19 and 18 day training camps at altitude spaced on year apart.  Most swimmers improved physiological markers through altitude training, but “the same individuals generally did not change their hemoglobin consistently from year to year. Thus, a 'responder' or 'non-responder' to altitude for hemoglobin does not appear to be a fixed trait.” 

Many studies such as the one cited above will measure progress through hemoglobin levels.  But is this change in physiology meaningful to actual swimming performance? 

Boone (2014) studied elite swimmers at a 3-4 week “live high-train high” altitude camp and compared them to a similar group training at sea level.  Authors noted that the altitude group improved hemoglobin mass and swim performance in the incremental step test and in the 3000m time trial more than the sea level group.  There was no significant difference between groups in the 4 x 50m test, though both groups did improve.  Thus, at least in this study, altitude appeared beneficial for swimming performance (but did they actually race faster when it mattered?). 

Garvican-Lewis (2013) studied elite water polo players in Australia over repeated exposures to altitude training and likewise found improvements in hemoglobin mass.  However, because competition performance is determined by many factors (especially in water polo), authors were guarded with the conclusion "since match performance is nuanced by many factors it is impossible to ascertain whether the increased hemoglobin contributed to Australia's Bronze medal."


As always with altitude training, remember that potential benefits may result from repeated exposure or through a sequestration effect in which swimmers may have the opportunity to focus on training without real world distractions.  Despite the abundance of literature, there’s still much we don’t fully understand.    

Though there is nothing groundbreaking in the recent literature, be reminded about the importance of individuality, especially when it much more convenient to package a team into a single training plan at a camp.  Also critical is that responses within individual athletes may change over time.  


  1. Chapman RF.  The individual response to training and competition at altitude.  Br J Sports Med. 2013 Dec;47 Suppl 1:i40-4. doi: 10.1136/bjsports-2013-092837
  2. Bonne TC1, Lundby CJørgensen SJohansen LMrgan MBech SRSander MPapoti MNordsborg NB.  "Live High-Train High" increases hemoglobin mass in Olympic swimmers.  Eur J Appl Physiol. 2014 Jul;114(7):1439-49. doi: 10.1007/s00421-014-2863-4. Epub 2014 Mar 27.
  3. Garvican-Lewis LA1, Clark SAPolglaze TMcFadden GGore CJ.  Ten days of simulated live high:train low altitude training increases Hbmass in elite water polo players.  Br J Sports Med. 2013 Dec;47 Suppl 1:i70-3. doi: 10.1136/bjsports-2013-092746.
  4. McLean BD1, Buttifant DGore CJWhite KKemp J.  Year-to-year variability in haemoglobin mass response to two altitude training camps.  Br J Sports Med. 2013 Dec;47 Suppl 1:i51-8. doi: 10.1136/bjsports-2013-092744.

Written by Allan Phillips is a certified strength and conditioning specialist (CSCS) and owner of Pike Athletics. He is also an ASCA Level II coach and USA Triathlon coach. Allan is a co-author of the Troubleshooting System and was selected by Dr. Mullen as an assistant editor of the Swimming Science Research Review. He is currently pursuing a Doctorate in Physical Therapy at US Army-Baylor University.

Friday Interview: Dr. Dennis O'Connell Discusses Grunting and Strength

1. Please introduce yourself to the readers (how you started in the profession, education, credentials, experience, etc.).
I started out becoming a certified physical education teacher in NY for grades K-12 and immediately pursued graduate education in Exercise Physiology at Kent State University. I was able to work in the field of heart disease prevention at Iowa State University and then returned to the University of Toledo to earn a Ph.D in Exercise Physiology. From there I moved into a position where I was Director of Research and Functional Electrical Stimulation for individuals with spinal cord injuries. I was then able to move into teaching Exercise Physiology to physical therapy students at UTHSC-San Antonio where I also became a physical therapist. For the past 20-years I have been a professor and Endowed Chair of Physical Therapy at Hardin-Simmons University. Along the way I have picked up a Doctor of Physical Therapy degree and am certified in Strength and Conditioning and Ergonomics.

2. You recently published an article on grunting and tennis serve velocity. What do we know and not know about grunting and performance?
Interestingly, there is published research on shouting during grip strength testing and during a kiap used in martial arts. Those studies show increases in force when subjects vocalized. Prior to our tennis study, we performed two research projects using grunting during the isometric dead lift. This involved pulling up on an immovable bar (and force transducer) at the level of subjects shins. The increases in force were small and similar to the grip studies mentioned above.
3. What did your study look at?
Our latest published study on tennis examined whether grunting or not-grunting increased serve and forehand velocities in male and female D-II and D-III tennis players. We had all subjects grunt as loudly as possible before the study began. During the study they had to grunt at a decibel 90% of what they achieved prior to the study for the trial to be counted as good. Conversely, in the non-grunt condition, the dB level had to be less than 30% of maximal dB level.

We also attached a device to the players racquets that measured force during a static or isometric forehand and serve.

4. What were the results of your study?
Our research shows that regardless of gender (we had approx equal numbers of males and females), perception about grunting (+ or -) or grunting experience, grunting increased serve and forehand velocities by about 5mph. This was a field study conducted on the tennis court.

Isometric serve and forehand forces increased from 15-20% with grunting.

5. Do you think yelling and grunting and yelling result in the same improvement?
I would guess that yelling and grunting yield similar results. By the way, we measured pectoralis muscle and external oblique muscle activity and found that they increased with grunting. Thus, there appears to a connection between brainstem cells that regulate inspiration and the motor cortex causing enhanced muscle recruitment with deep exhalation.

6. Do you think these results to other sports?
I would guess that yelling or grunting would cause increases in forces, velocities, etc. in dynamic sports and to a lesser extent in isometric or static force production situations.

7. How can future research on this subject improve our knowledge?
If would be nice to examine the brain during grunting and force production to learn if my hypothesis of increased communication between the breathing and motor control centers increases during forced or deep exhalation.

8. What research or projects are you currently working on or should we look from you in the future?
We have completed a study in the lab where we had D-III male and female tennis players push against a force place mimicking a forehand stroke. We asked them to either deeply exhale, deeply inhale, perform a straining or Valsalva maneuver and grunt. Forces increased significantly with grunting and these forces were not different than when forcefully (and moreo quietly) exhaling. Forces with deep inhalation or during straining were significantly less. Thus, one may be able to substitute deep exhalation for grunting and still get the same increased force production. We are writing this study up for publication and hope to officially share the results with the scientific community in the near future.

We have also just completed a study of female collegiate soccer and volleyball players who were tested before and after practice with a test battery called the Functional Movement Screen (FMS). It has been shown in some populations to predict who would get injured during a season. Since players are injured during practice or games, we thought it would be novel to see what happened to the FMS scores if they were fatigued (which is when injuries happen). Interestingly, their scores stayed the same or improved. They did not worsen as we expected. Additionally, we did not find this test to be predictive of injuries in our female sample. Both of these studies have been submitted for presentation at an upcoming national physical therapy meeting.

We are currently performing a study on windmill assembly workers where we are testing the effects of their current static stretching routine vs. a dynamic ballistic warm-up. We are hoping that we might create a better warm-up for them to prevent work-related injuries.

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.

USRPT and the Concept of Failure

Take Home Points on USRPT and the Concept of Failure
  1. Failing reps carries negative connotations, often leading to poor understanding of USRPT.
  2. Failure, as defined by the USRPT system, is a key element for set progress It is important to properly define failure for optimal application

One of the most misunderstood yet critical elements of the USRPT system is the concept of failure.  For those currently applying USRPT in their own programs, this post will be very elementary.  But for those with a passing knowledge of USRPT, this post will hopefully clear up misunderstanding.  Unfortunately, a full description of USRPT is impossible in this single article, but most readers are at least aware that USRPT involves copious amounts of repetitions performed at (or very near) race pace. (for previous discussion on this site, see HIT, HIIT, USRPT, Traditional Training)

With the growing awareness of the value in race pace training, more teams have
integrated what they believe to be USRPT.  Certainly, completing many high quality, successful repetitions is a key component of any training plan.  Yet some might call low doses of race pace training to be relatively meaningless if performed in low volumes.  However, most would also agree that training to excess would stifle improvement as well. 

Failure lies at the center of this discussion and is largely what separates the USRPT system from “just doing a bunch of race pace reps to cover our bases.”  When most think of failure, they think of complete physical failure where body is completely unable to perform the demands asked of it.  Best example is doing a weightlifting set in which the weight simply won’t move at the end of the set.  Now, complete failure in the pool is rare as the body can typically still function after a failed rep but at lower loads, even after complete exhaustion. (ie, Noakes Central Governor Theory...See Neural Fatigue and Swimming for related discussion)

USRPT employs a different concept of failure, which we might define as goal time failure.  In goal time failure, it means the swimmer has failed to achieve the goal time for a particular.  In fact, copious volume may still be possible for the remainder of the session and through the rest of the day.  Failure may also be caused by losing mental focus, poor execution of a turn, or extrinsic factors (collision, etc), the latter of which are not “counted against” the swimmer. 

Failure in this latter context involves separate purposes.  One purpose is to allow the swimmer to cognitively reevaluate what is necessary to get back on pace for the remainder of the set.  Secondly, pursuing failure is one way to go right up to the edge of work tolerance without going overboard.  There are other safeguards built into the system to ensure overreaching does not occur, but for now just understand that goal time failure is one of these safeguards. 

In a “traditional set” or even in a High Intensity Interval set (typically shorter rest than USRPT) the rest period becomes less and less until an interval is missed.  By that point the swimmer has exhausted much of his or her reserves hanging on for several reps.  The swimmer may be as much as 10 seconds off goal pace (or more if doing long distance repeats).  In USRPT, rest and pace are held constant. 


Training to failure evokes negative connotations that lead to many misunderstandings in the application of USRPT training, some of which I had personally bought into before reading the full story.  It is hard to discuss failure in isolation of the whole system, but hopefully this clears up some misconceptions and distinguishes USRPT failure from negatively associated failure in tradition or HIIT.  

Written by Allan Phillips is a certified strength and conditioning specialist (CSCS) and owner of Pike Athletics. He is also an ASCA Level II coach and USA Triathlon coach. Allan is a co-author of the Troubleshooting System and was selected by Dr. Mullen as an assistant editor of the Swimming Science Research Review. He is currently pursuing a Doctorate in Physical Therapy at US Army-Baylor University.

Three Tips for Maintaining Speed at the End of a Race

Take Home Points on Three Tips for Maintaining Speed at the End of a Race

  1. Individual race analyses are required for determining the reason of fatigue or failure.
  2. Improved pacing, BFR and/or HIIT training may help improve a swimmer finish a race. 
A few months back I performed a few above water swimming analyses on Brad Tandy and Kevin Cordes. In these pieces, I recommend maintaining swimming velocity at the end of the race, specifically maintaining pull-out distance for Kevin Cordes. Now, just knowing their stroke rates and pull-out distances decreased doesn't give me the specific reason for this impairment. As a comment suggested, this recommendation needed specifics for implementation. Unfortunately, not knowing the exact mechanism for fatigue limits the ability for recommendation. Here are 3 tips for improving the finish of a race:

1. Improved Pacing

Pacing is a highly complex topic, which Ross Tucker has written about extensively about on the Science of Sport. If you are looking for more about the physiology and psychology of pacing, check out his posts on the subject.

In swimming, it seems an even paced strategy is ideal for swimming performance. Unfortunately, this is easier said then done, especially in a high-level meet. For swimmers who loose their speed at the end of the race [like Tandy and Cordes], perhaps their race plan was closer to a "fly and die" swimming strategy, compared to an even pace strategy. Many think the 50 free does not typically require much pacing, as near top end speeds are required from the beginning of the race. Many elite swimmers [especially 50-meter] swimmers indicate there is some pacing to the 50-meter, but not nearly as much for a 100 - m or longer race. If a swimmer is trying to improve their finishing speed, perhaps they should try a more even paced strategy.

2. Blood Flow Resistance Training (AKA Kaatsu, AKA Occlusion Training)

Another main reason for fatigue at the end of a race is metabolic stress. This results in
toxic soup filling in the body creating high discomfort. Now, it has been a while since I've mention this form of training, yet the possibility of its use still exist.

The use of blood flow resistance training, is thought to increase muscle hypertrophy and strength at low-intensity resistance training. Studies on the use of occlusion training and swimming did not previously exist, yet one could speculate occlusion training may increase training adaptations. This study looked at the effects of swimming occlusion training.

Elfattach (2011) had twenty well trained male swimmers (mean age 17) split into a control and experimental group. Each group practiced a total of 12-hours per week. Both groups performed the same training, but the experimental group used resistance bands around their proximal arms on Saturday and Tuesday and legs on Monday and Thursday. Each session was between 5 - 6 kilometers. The bands were 50 - 80 mm Hg for the arms and 80 - 120 mm Hg for the legs. The main swimming set was 8x25-m on two minutes followed by 2x50-m on five minutes on Saturday, Sunday, and Monday. On the other days, the main set was two rounds of 8x12.5-m on one minute and 2x50-m on five minutes.

Before and after the training, 6x25-meter sprints were performed as the test set. Blood markers were also assessed on the days of the test sets.

No differences were noted in plasma lactate, pyruvate concentration, lactate/pyruvate ratio, and creatine kinase and lactate dehydrogenase prior to the training. After the training, blood lactate, pyruvate levels, and lactate/pyruvate ratios were increased significantly following the exercise bout for both groups. Lactate, creatine kinase were decreased significantly following the experimental group compared to the control. Pyruvate, lactate/pyruvate ratio were increased significantly in the experimental group. Lactate dehydrogenase was not different between groups.
Arm and leg girth was significantly greater in the experimental group.

No significant differences were noted in the 6x25-meter test set.

It seems the occlusion training amplified phosphate depletion and lactic acid production compared to the control group. This suggests the anaerobic capacity was increased in the experimental group. The increase in muscle size may occur due to the mechanical response to occlusion.

This suggests anaerobic capacity and muscle girth increase with occlusion training. However, the implications of these for swimming are still uncertain, as they may be irrelevant. More studies must look at more applicable training, more practical test sets, and more detailed methods.

Now, this training did not improve the 6x25-meter test set, suggesting it doesn't improve this test. However, I think it used for the correct swimmer, one who doesn't tolerate metabolic waste well, improvements are feasible.

Overall, BFR training requires more research, but if done safely in an mature population, I do think it can help those finish a race who have high metabolic stress and poor abilities to tolerate metabolic stress.

An example set of BFR training with swimming is difficult for suggestion, however performing repeats (like the suggestion below) or maximal efforts to the point of failure (ie 12x35-m @4:00) may help an athlete improve metabolic waste tolerance.

3. Hi-Intensity Interval Training (HIIT)

HIIT is extremely popular in the general exercise community and I think it can play a large role in swimmers who can not finish at the end of the race, especially if they have biomechanical faults. Recent research on HIIT, indicates great variability in response of HIIT training, so it won't work for everyone, but if someone has a physiological weakness (lower VO2max) or is incapable of maintaining correct biomechanics at the end of a race, HIIT may be beneficial (Astorino 2014). 

An example set would be 20x25 @:25, holding 4th 25 of a 100 pace. Now, this looks like a USRPT set, but remember USRPT is a training approach, this is simply a set. However, some may respond well to 20, some may only be capable or 12. Remember individualization and progression is key.


Once again, understanding the mechanism of fatigue is huge component for improvement. These are three possible methods for improving a swimmer finish the race. If you are an athlete who has difficulties finishing a race, consult with your coach on the main cause of fatigue, work on it, and see if you improve!


  1. Elfattach, A, Salen, H. Effect of Occlusion Swimming Training on Physiological Biomarkers and Swimming Performance. WJSS 4(1): 70-75, 2011.
  2. Astorino TA, Schubert MM. Individual Responses to Completion of Short-Term and Chronic Interval Training: A Retrospective Study. PLoS ONE 9(5): e97638, 2014.
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.