Friday Interview: Carlos Balsalobre-Fernández Discusses Neuromuscular Fatigue

1. Please introduce yourself to the readers (how you started in the profession, education, credentials, experience, etc.).
When I went to the college for the first time, I started a BSc. on Math Sciences. In the mean time, I was practicing martial arts on a local gym for several years (I’m a Karate black belt) when, suddenly, the instructor had to left the classes and the gym owners needed to find another instructor as soon as possible. Since I was the most advanced student, they asked me to be the new instructor, and that was my very first contact with the world of training, which I became to love so much.

Maybe due to my math education, I wanted to make my trainings more scientific and research-based and, one day, I decided to quit Math Sciences to study Sports Sciences. My main interests was high-performance sports and resistance training so, when I finished my BSc. on Sports Sciences, I studied two MSc. on High Performance in Sports at the Spanish Olympic Committee and Pablo de Olavide University which were directed by the strength-training expert Juan José González-Badillo. Also, I got the NSCA CPT and CSCS certifications. Currently, I’m working on the Autonomous University of Madrid finishing my PhD.

I’ve worked conducting different strength tests to several high-level athletes, like the Spanish Karate Team, the Spanish Fencing Team, professional basketball players or elite track&field runners. Also, I’ve worked as a S&C in a young elite basketball team and, currently, I’m supervising the strength training of one Spanish high-level middle-distance runner.

2. You recently published an article on counter movement jump (CMJ), cortisol before and after a running race. What types of exercise cause greater neuromuscular fatigue?
Well, that’s a tricky question, since the causes of neuromuscular fatigue are not clearly known. First of all, activities with high impact on the neuromuscular system, like resistance training, are known to generate a remarkable neuromuscular fatigue. For example, a few years ago Sánchez-Medina and González-Badillo demonstrated that the decrease on velocity production on the squat exercise is highly correlated with a marker of neuromuscular fatigue like the CMJ.

However, neuromuscular fatigue has shown to occur after several different activities. For example, we have demonstrated that a middle and long distance competition produces a significant reduction on the CMJ; according to previous research that shown that a marathon run also produces neuromuscular fatigue. In fact, a recent study of us, unpublished yet, demonstrated that 1-hour fencing assault training induces a remarkable neuromuscular fatigue.

Summarizing the CMJ, as an indicator of neuromuscular fatigue, has shown to be decreased by different kinds of activities, no matter its main energy contribution or the duration of the stimulus. In fact, several authors consider the general term “fatigue” as a decrease on the ability to produce force, so every activity that produces an impairment on physical performance (run slower, throw closer, jump lower) are susceptible to lower the CMJ height.

3. What methods are possible for measuring neuromuscular fatigue?
As I said in the previous question, fatigue, ultimately, is a decrease of the ability to produce force. There are a lot of different ways to test the ability of the subject to generate force. For example, the velocity of contraction of the muscle fibers (twitch) could be used to detect impairments on the force production, as well as other sophisticated, invasive lab test. However, in the field, the best way to assess neuromuscular fatigue is through some strength-performance tests like the CMJ, the 20 meter sprint, bench press or squat velocity, etc. Personally, I would suggest the use of the CMJ since it is really easy and fast to perform almost everywhere, it doesn’t disrupt the athletes training and has shown very good relationships with other markers of fatigue on previous research.

4. What specifically did your study measure and why?
A lot is known about the lactate production or energy contribution to high-level middle and long-distance competitions, but the studies analyzing its effects on the neuromuscular performance were just a few. However, taking into account previous research, we wanted to know if the CMJ could be used to assess fatigue on high-level athletes after the most important competition of the season (the Spanish Track and Field National Championships), and how this marker of neuromuscular fatigue is related to other indicators of fatigue.

For this, we measured the salivary-free cortisol, the CMJ and the rate of perceived exertion just before and after the competition. Also, we compared the scores of the CMJ and the awakening salivary-free cortisol on the competition day in comparison with a pre-competition baseline.

5. What were the results of your study?
First, we saw a significant decrease on the CMJ and a significant increase on the cortisol after the race, and moreover, the CMJ decrease was related with the rate of perceived exertion and the post-race cortisol increase. That means that there was a significant trend for which the athletes with greater increases on the cortisol and higher perceived exertion were those with higher CMJ decreases after the competition. Also, it was interesting to found that the athletes had significantly greater awakening cortisol (+117.5%) and CMJ (+6.5%) levels the day of the competition than during a 4 weeks pre-competition baseline.

6. What were the practical implications for coaches and swimmers from your study?
Well, I think that the most important conclusion of this study is that the CMJ is a very appropriate tool to assess fatigue after an extenuate endurance event, being related to a hormonal stress marker like the salivary-free cortisol. Since the CMJ is very easy to measure on field situations with different technologies, I think that coaches could use it to assess the degree of fatigue of the swimmers not only after a competition, but, more importantly, during the training.

7. Do you think CMJ is sensitive enough to monitor fatigue after sprint competitions?
Of course I do. In fact, a college and friend of mine, Dr. Pedro Jiménez-Reyes is working a lot on this issue. For example, he has demonstrated that the decrease of speed on a sprint training session is related to the decrease of the CMJ measured after every single sprint.

Although a sprint competition involves a short stimulus (a few seconds), it could produce a remarkable degree of fatigue. Think about the following: do you think that Usain Bolt could run faster after a maximal 100-meter competition? Obviously the answer is no, because if it was yes, the sprinters would perform a maximal 100m sprint right before the competition, and that is just crazy. Thus, if some fatigue is produced affecting the ability of the athlete to produce force, it is very probable that the CMJ could detect it.

8. What are some risks of excessive training during neuromuscular and hormonal fatigue?
Again, if the fatigue is an impairment on the force production, training in that situation could lead to less efficient movements and to a lose of control and coordination of the muscles, which is known to increase the risk of injuries. Besides the risks of injuries, training with high degrees of fatigue is known to decrease physical performance in comparison with other kinds of training.

For example, it was demonstrated that performing repetitions until failure (a very common practice on resistance training) decrease the power production on some exercises, while training with the half of the repetitions that could be done increase it. Train with fatigue is equal to train producing less velocity to the movement and less power. I found the researches about training with less repetitions per set, like the cluster training method, really interesting and promising.

9. Do you think athletes train in this level of fatigue too often?
Absolutely. In fact, it is very common to hear phrases like “no pain, no gain” in the field, even in elite high performance centers that are supposed to be supervised by educated professionals.

I think that the evolution of the training methods is not to use new materials, technologies etc., but to learn to train less and more efficiently. In some specific moments, a training session could last no more than 20 minutes (for example, to produce a post-activation potentiation the day before a competition), and that is very hard to understand for some athletes and coaches.

10. What research or projects are you currently working on or should we look from you in the future?
I’m in the process of publication of two more papers about the relationships between some markers of fatigue, training load and strength on high-level middle and distance runners. Also, I’m really involved on the development of an iPhone app to measure the CMJ. We have tested the app on the laboratory with a high-tech force platform. We measured 100 CMJ with the app and with the force platform and we compared the values using some validity and reliability statistical techniques, and the results were really promising: a Pearson correlation coefficient of r=0.995 and a mean difference of 1.2cm between instruments, besides some other reliability techniques that the readers may not know. The app is called “My Jump” and will be available on June 2014. The paper about the validation of My Jump is already submitted to a top peer-review journal, so, if reviewers like it, it should be published in the near future.

You can follow Carlos on Twitter (@cbalsalobre). He is the author of “Strength Training: New Methodological Perspectives”, a free multimedia iBooks, available for iPad and Mac in Spanish (English version in progress). It can be downloaded for free on https://itunes.apple.com/es/book/entrenamiento-fuerza-nuevas/id808033756?mt=13. Also, he is developing My Jump (@MyJumpApp), an app for iPhone and iPad scientifically validated for measuring vertical jump performance.

Friday Interview: Benjamin Holfelder and Niklas Brown Discuss Individual Anaerobic Threshold in Swimmers

1. Please introduce yourself to the readers (how you started in the profession, education, credentials, experience, etc.).
The following questions will be answered by Benjamin Holfelder and Niklas Brown, two of the three authors who published the article referred to in this interview. Benjamin Holfelder was a competitive swimmer for 15 years (national level in his age group). He has a diploma in sports science with specialization on performance sports. In his diploma thesis he analyzed the lactate curve characteristics in high performance swimming. Niklas Brown has a diploma in sports science with the same specialization. Since April 2011, both are academic assistants at the Institute of Sport and Exercise Science, University of Stuttgart (Germany), where Benjamin is teaching in the major subject swimming. Niklas is doing research in biomechanics and performance diagnostics.

2. You recently published an article on individual anaerobic threshold (IAT). First, can

you describe what IAT is?
The individual anaerobic threshold (IAT) is the point on a lactate curve / the intensity where lactate starts to accumulate, which means that lactate production is greater than lactate clearance. It is said, that the energy supply in intensities below the IAT is predominantly aerobic, above the IAT predominantly anaerobic. There are many different methods and test protocols to determine the IAT. This makes it difficult to compare and interpret results of lactate tests, especially when different protocols are used.

3. Why is IAT important for a coach?
In our opinion not only the IAT, but also other variables of the lactate curve e.g. maximum lactate concentration or the inclination of the curve, are important when interpreting results of a lactate test to get information about the constitution of an athlete. According to the lactate threshold training model the IAT helps a coach to determine training intensities individual for each athlete under consideration of the athletes’ main event. Training with intensities above the IAT improves the anaerobic endurance capacity, training below the IAT enhances aerobic endurance capacity and training at IAT improves the ability of the body to change the energy supply from aerobic to anaerobic state.

4. What are some common myths about lactate?Some common myths about lactate are still:

  • Muscle fatigue / soreness is the result of a too high lactate concentration.
  • A certain lactate value means the same training intensity for each individual.
  • The right shift of the lactate curve shows an improvement of the endurance capacity in any case.
  • The anaerobic threshold is equal to a lactate concentration of 4mmol/l.
  • Lactate is only a waste product of glycolysis, produced during exercise as a result of O2 debt.
  • Lactate is a key factor of causing acidosis-induced tissue damage. 
5. What do we truly know about lactate and fatigue?
In the last years the view about lactate completely changed. Lactate, the formerly referred key factor of fatigue became a signaling molecule, fuel and a gluconeogenic substrate. Therefore, lactate helps to maintain a certain exercise load and is involved in activating signaling pathways for training adaptations. Studies showed the positive effects of lactate on the performance of fatigued muscles e.g. by supporting the activity of Cl—channels, which are essential in maintaining action potentials for muscle contractions. Current state of research shows, that there is no evidence of the negative effects of lactate regarding muscular fatigue. Rather, muscular fatigue seems to be a multifactorial phenomenon
[see Lactate is a Scapegoat for Fatigue]. Subsequently, we would like to mention some factors producing fatigue, which are discussed:
  • Accumulation of inorganic phosphate and ammonia
  • Increase of adenosine diphosphate (ADP)
  • Reduced release of calcium from the sarcoplasmic reticulum
  • Release of H+ and its associated consequences
Summarized, muscular fatigue is a consequence of local processes in the muscle cell, thus not a result of lactate accumulation. Also central nervous factors seem to play a less important role in muscular fatigue.

6. You mention in your article that lactate is currently the gold standard test, but what still needs to be shown about lactate?


That lactate diagnostics is currently the gold standard test, is mentioned in several publications. The reason for this is possibly the relatively simple application in the field and the knowledge about lactate metabolism. Nevertheless, there are a few things, which need to be shown. In the last years a lot of studies analyzed physiological mechanisms like the lactate-shuttle theories or mentioned the role of lactate as a signaling molecule. However, it is still not completely clear what this knowledge implies for the training planning and how coaches and athletes can benefit. Other needs in the research area of lactate are the identification of further lactate affecting factors and especially the enlargement of understanding the interaction of this identified factors. Furthermore, it seems to be really important to understand how special training input influences the individual lactate kinetics in the short, medium and long term.

7. What are some other potential tests for monitoring fatigue and energy metabolism?
Another well-known method for monitoring energy metabolism is the respiratory gas analysis on a bike ergometer, a treadmill or in the field. The development of the material (e.g. size and form of the breathing masks) in the last years simplifies the use of the respiratory gas analysis in the water, e.g. in a pool or a stream channel. The application of this method in the field allows statements about the cardiopulmonary system and the economy of the swimming technique. In contrast, the results of the lactate diagnostics give more information about the physiological and metabolic state. A disadvantage of the respiratory gas analysis in the field is the more extensive application and the more expensive equipment (e.g. stream channel) compared to lactate diagnostics.

8. What were the main findings of your study?
The main findings of our study were, that we could identify the influence, especially of sex and distance, on lactate parameters in swimming, explained with current physiological knowledge. We could show on a large data set, that women show lower lactate concentrations with higher percentage of the individual personal best, compared to men. Based on the knowledge about anthropometric, hormonal and genetic differences this fact does not seem surprising, but as far as we know, only a few studies reported sex differences of lactate metabolism in sports. The influence of the factor distance on the lactate characteristics, explained by the increasing importance of the endurance capacity with longer distances and the therefore needed differentiated muscle fiber type distribution is also comprehensible. Our results highlight the importance of a distance specific interpretation of the results of lactate diagnostics and imply a distance specific planning of training input. It has to be mentioned that the results of lactate step tests depend on the step length, which could have influenced our results for the factor distance. In terms of methodology we could show, with applying the multi level analysis, that lactate parameters are dynamic and they are the result of the interaction of different factors e.g. training input or nutrition.

9. How can coaches use the results of your study specifically?
Coaches can use / benefit of our results, if they consider following points:

  1. Because of the analyzed significant effects of sex, distance and stroke, we recommend to compare longitudinal results of lactate diagnostics only under steady conditions, which means applying the same test protocol and threshold concept, conducted with the same stroke and distance.
  2. It seems to be important to take more factors into account than just the IAT when interpreting the results of lactate tests. A high IAT does not necessarily mean a bad endurance capacity, but could mean, together with a high maximum lactate value, that the athlete is a sprinter.
  3. Lower lactate concentrations in women compared to men, do not necessarily indicate lower physical stress.
  4. The effect of the factor distance implies a distance specific planning of training input, which means that not only the volume in kilometers, but also the quality of training is important.
10. You also indicate, traditional training models may not be appropriate for sprint and middle distance swimmers based on your findings. What type of training do you think is best in these specialists?
Yes, we wrote that current training regimes in swimming seem to be characterized by an aerobic predominance. This is possibly not up to date anymore for sprint and middle distances, because too much training in low and middle intensities supports the development of a maximum endurance capacity, which is maybe not required, not optimal and not specific enough for sprint and middle distance swimmers. Under consideration of the physiological knowledge it would be the aim for such specialists to train for an optimum endurance capacity. This means, that the quality of training becomes the key factor and not the volume in kilometers. Of course, general training in early childhood and adolescence is still important, but too much general training in high performance sports could result in a loss of adaptability. Therefore a sprinter should try to maintain the dominance of muscle fiber type II and train in terms of an "optimum" endurance capacity. However the problem remains that the "optimum" is individual and the concepts of training planning differs between trainers. According to actual knowledge it is unclear whether signaling pathways initiated by weight training, high intensity training or endurance training overlap or hinder each other. These ideas of different initiated pathways by different training input and the lack of evidence for the effect of threshold training lead to a critical perspective on the "classical" threshold training. Derived from this view, a training plan relating to the polarized training model would make sense for these specialists. However, it has to be said that these ideas need more research before it is possible to make more reliable statements.

11. What research or projects are you currently working on or should we look from you in the future?
At the moment Benjamin Holfelder is working on a project for his doctoral degree about the relationship between the motor and cognitive development in children. In the field of swimming it would be interesting to analyze the relationship between swim-specific strength parameters and the characteristics of the lactate curve.

Brief Swimming Review Edition 12

<mainpage><brief Swimming Review Edition 12></MainPage><archivepage><Shoulder, backstroke, Starts, Breathing, fatigue, Brief Swimming Review, ></ArchivePage><br /> <itempage><blogger><this brief swimming review discusses shoulder pain perceptions, backstroke start technique, apnea, and fatigue in collegiate swimmers.></blogger></itempage>

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 for complete monthly article reviews for only $10/month! 

Perceptions of Shoulder Pain in Swimmer

This will be short, as I'm working on a long post on this subject, but a group of researchers surveyed 102 age-group swimmers (13 - 18 years) about their perceptions and practice habits with shoulder pain.

"Club swimmers have a high frequency of practices, comparable to collegiate and professional swimmers. They believe that shoulder pain is normal and should be tolerated to complete practice. The association between the swimmers' attitudes and behaviors indicates that the interventions that educate the swimmers, coaches, and parents may be effective in changing their attitudes and ultimately their behaviors, decreasing the number of athletes who train with shoulder pain (Hibberd 2013)".


Overall, 85% of high school-aged clubs swimmers reported mild shoulder pain in the past year, 61% reported moderate shoulder pain, and 21% reported severe shoulder pain. Of these, only 14% had been to a physician. These are inappropriate perceptions and practices by the swimmers which are not receiving adequate education about shoulder pain from their coach. In the Swimmer's Shoulder 2nd edition (ETA 10/16/13), a whole video is dedicated to educating coaches and swimmers about shoulder pain, soreness, and what to do! 

Pre-order the 2nd edition before 10/16/13 and receive a $15 discount! This edition includes an extra seminar by Dr. John, DPT discussing shoulder pain, updated text (over 50 references added), and the coaches and swimmers shoulder pain perception video on top of all the other contents.



Take Home Points:
  1. Too many swimmers have shoulder pain.
  2. This shoulder pain is not managed properly.
  3. Don't just pop a few Advil and swim through it.

Related Reading

How to Prevent Swimmer's Shoulder
Dr. Detective: Digging for Clues Behind Shoulder Labrum Pain

Entry Hole in Backstroke

The backstroke start is clearly the most unique of the different starts in swimming. Yet, littler research has investigated this style of start.

"A total of 16 well-trained Japanese competitive swimmers were divided into two groups (backstroke specialists and non-specialists) to compare their backstroke start motions. Their backstroke motions were videotaped, and two-dimensional co-ordinates for the swimmers were obtained from the video images using direct linear transformation methods (Takeda 2013)."

Backstroke specialists had significantly shorter 5 m time, higher position of the toe at the signal and
of the hip at toe-off, a significantly larger hip joint angle at toe-off, and a significantly higher angular velocity of the high joint compared to non-specialists.

Clearly, the backstroke specialists are more skilled in the kinematics in this style of start, most notably:
  1. Arched-back posture with a large hip joint angle and hip hip position at toe-off
  2. Early initiation of the extension and maintenance of a higher extension speed at the hip joints facilitate the arched-back posture.
Take Home Point:
  1. A focus on the hip joint movement appears most pertinent for entering in one hole during the backstroke start. This likely won't change with the implementation of the new Omega backstroke starts.

Related Reading

Pros and Cons of New Omega Backstroke Starting Platform

Apnea in Swimmers

Swimming consists of frequent breath holds, manipulated by breath holds and breathing patterns. However, the physiological effects of breath holding are not well appreciated. This study took 15 national or regional level swimmers and monitored them during four broken 100-m freestyle performances (4x25 @0:30):
  1. Fins with normal breathing
  2. Without fins with normal breathing
  3. Apnea with fins
  4. Apnea without fins
The results showed swimming was faster with fins. Apnea did not change lacatemia, but did decrease arterial oxygen saturation during both apnea conditions. Swimming with apnea also decreased heart rate and performance. However, apnea with fins resulted in non-significantly different heart rate compared to normal swimming.

"Saliva dehydroepiandrosterone was increased compared with basal values whatever the trial, whereas no change was found in saliva cortisol or testosterone (Guimard 2013)."

Take Home Points:
  1. Fin swimming alters cardiovascular demand.
  2. Apnea decreases performance.
  3. Fin swimming during apnea has similar cardiovascular demands as regular swimming, but the biomechanics are likely different.

Related Reading

Individual Breathing Patterns are King!
Friday Interview: Dr. Mitch Lomax
Breathing and Swimmers' Posture
Breathing During Sprinting

Factors Influencing Fatigue in Canadian Swimmers

Monitoring fatigue is a difficult avenue in sports, as subjectivity has been the main source of
information. However, with new, cost-effective methods (heart rate variability [article in work]) may help monitor and individualize fatigue monitoring.

This study looked at factors which influenced fatigue status in Canadian University swimmers (M=14, F=11). Orthostatic heart rate test and a questionnaire on mood state was provided throughout the year.

Overall, the swimmers were excessively fatigue throughout the competitive season. The results note a flexibility structure of training positively influenced perception of fatigue, while teammate expectations and school/work/sleep balance negatively influenced fatigue.
Orthostatic heart rate and questionnaires reflected training volume, but it seems the taper periods did not provide adequate recovery. Perhaps fatigue in high level swimmers is a multi-variable, requiring better individual understanding of fatigue as well as monitoring of non-training parameters (life, sleep, etc.).

Take Home Points:
  1. Fatigue is dependent on more than only training volume.
  2. High-level swimmers should receive periods of taper or management methods of teammate expectations and school/work/sleep.
  3. Flexible structure may decrease stress.
  4. Collegiate swimmers are likely overtrained throughout the season.

Related Reading

Reliability Rating of Perceived Exertion in Swimming
Neural Fatigue and Swimming


References:

  1. Takeda T, Itoi O, Takagi H, Tsubakimoto S. Kinematic analysis of the backstroke start: differences between backstroke specialists and non-specialists. J Sports Sci. 2013 Oct 9. [Epub ahead of print]
  2. Guimard A, Prieur F, Zorgati H, Morin D, Lasne F, Collomp K. ACUTE APNEA SWIMMING: METABOLIC RESPONSES AND PERFORMANCE. J Strength Cond Res. 2013 Oct 7. [Epub ahead of print]
  3. Kennedy MD, Tamminen KA, Holt NL.Factors that influence fatigue status in Canadian university swimmers. J Sports Sci. 2013;31(5):554-64. doi: 10.1080/02640414.2012.738927. Epub 2012 Nov 9.
  4. Hibberd EE, Myers JB. Practice Habits and Attitudes and Behaviors Concerning Shoulder Pain in High School Competitive Club Swimmers.  Clin J Sport Med. 2013 Sep 13. [Epub ahead of print]
By Dr. G. John Mullen received his Doctorate in Physical Therapy from the University of Southern California and a Bachelor of Science of Health from Purdue University where he swam collegiately. He is the founder of Mullen Physical Therapy, the Center of Optimal Restoration, head strength coach at Santa Clara Swim Club, creator of the Swimmer's Shoulder System, Troubleshooting System, and chief editor of the Swimming Science Research Review.

How to Prevent Swimming Burnout


How to Prevent Swimming Burnout

Take Home Points on How to Prevent Swimming Burnout

  1. Physiological capacities are limited after maturation.
  2. Technique is the largest contributor of success, especially after maturation.
  3. Burnout is higher in women, potentially due to earlier development and longer period of plateauing. 
Improvements in swimming naturally occur during maturation, in fact, one can expect 3 –
4% improvement during these years (Sweetenham 2013). Although technique is the main determinant of success, even in age-group swimmers, many swimmers improve with any program or technique during maturation (Watanabe 2005). Improvement with various programming often confuses many into believing into non-ideal training pedagogy, as increases in size mask skill improvement and acquisition.

Physiological Capacities

Improving physiological capacities is limited after ~8 weeks of training, but individuality does exist (Costill 1991; Kamel 2002; Savage 1981). Once conditioning and growth cease, the potential to improve through conditioning is limited (Novitsky 1998). These limited capacities prevent many swimmers from improving after maturation, as is commonly see in many Senior and collegiate programs.

Technique Emphasis

As mentioned, technique is the main determinant of swimming success in age-group swimmers. After growth, technique is also the main determinant of success (Cappaert 1996; D’Acquisto 2004). Improvements in these skills also result in greater and quicker performance improvements than other forms of training (Havriluk 2010).
After maturation, one must remember skill improvement is still possible. Unfortunately, many people continue to attempt to improve physiological capacities, through arduous training volumes and intensities when biomechanics and swimming skill provide the greatest return on investment!

Women and Burnout

Women are commonly associated with burnout more than men, likely due to longer
periods of not improving and a greater recovery capacity, resulting in many women putting even more emphasis on physiological capacities. Unfortunately, this strategy has a poor return on investment, often minimizing performance gains and increasing the risk of injury (Hibberd 2013). Technique plays an even more important role in success in women and when this area is not emphasized performance gains are limited (Cappaert 1996). 

Conclusion

Overall, skill improvement is possible for all coaches, but proper motor learning principles are necessary for improvement. These skills have been discussed here (see below), by Dr. Rushall, and Ludo, specifically for swimming. Knowing these principles, as well as ideal biomechanics will help improve swimming skill and likely minimize burnout from injury or disinterest in the sport, as continual improvement is the best prevention for burnout!  

Further Reading

References

  1. Costill DL, Thomas R, Robergs RA, Pascoe D, Lambert C, Barr S, Fink WJ. Adaptations to swimming training: influence of training volume. Med Sci Sports Exerc. 1991 Mar;23(3):371-7.
  2. Novitsky, SA. No change in energy systems power rate production constants over a competitive swimming season. Medicine and Science in Sports and Exercise. 1998; 30(5), Supplement abstract 613.
  3. Cappaert, JM., Kolmogorov  S., Walker, J., Skinner, J., Rodriguez, F., & Gordon, BJ.  Active drag measurements in elite US swimmers. Medicine and Science in Exercise and Sports. 1996: 28(5), Supplement abstract 279.
  4. Troup, A. P. Hollander, D. Strasse, S. W. Trappe, J. M. Cappaer TA. Trappe (Eds.), Biomechanics and Medicine in Swimming VII (pp. 76-80). London: E & FN Spon.
  5. D'Acquisto LJ, Berry, J. Energetic and technique characteristics of trained collegiate male swimmers. Sixth IOC World Congress on Sport Sciences, abstract. 2002; p. 23.
  6. Watanabe, M., & Takai, S. Analysis of factors on development of performance in young swimmers. Medicine and Science in Sports and Exercise. 2005;37(5), Supplement abstract 416.
  7. Havriluk, R.  Performance level differences in swimming: Relative contributions of strength and technique. In P-L. Kjendlie, R. K. Stallman, J. Cabri (Eds.) Biomechanics and Medicine in Swimming XI. Norwegian School of Sport Science, Oslo. 2010.
  8. Kamel, KS., McLean, SP, Sharp RL. Biomechanical and physiological adaptation to twelve weeks of competitive swimming training. Sixth IOC World Congress on Sport Sciences, abstract, p. 74.
  9. Savage MV, Brown SL, Savage P, Bannister EW. Physiological and performance correlates of training in swimmers. Paper presented at the Annual Meeting of the Canadian Association of Sport Sciences, Halifax. 1991; Oct.
  10. Hibberd EE, Myers JB. Practice Habits and Attitudes and Behaviors Concerning Shoulder Pain in High School Competitive Club Swimmers. Clin J Sport Med. 2013 Sep 13. [Epub ahead of print]
  11. Sweetenham B. ASCA Swimming Newsletter. 2013.
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 founder of Mullen Physical Therapy, the Center of Optimal Restoration, head strength coach at Santa Clara Swim Club, creator of the Swimmer's Shoulder System, and chief editor of the Swimming Science Research Review.

Brief Swimming Review Volume 1 Edition 9

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

Cross-education for Rehabilitation
Cross-education is the phenomenon when strengthening one arm, strengthens the untrained arm. This is a valuable and effective tool when rehabilitating the other arm isn't an option: "For the fractured hand, the training group (17.3±7.4kg) was significantly stronger than the control group (11.8±5.8kg) at 12 weeks postfracture (P<.017) (Magnus 2013)."

This phenomenon may not only cross arms, but could potentially cross to the legs. For this, it is advised to still kick and train (at least the other arm) during an injury. 

Further Reading
Peak Force Correlated with Starting Success
The Omega OSB11 starts are known to improve performance, but what characteristics lead to a better start? This study looked to determine which variables were correlated with an improved start:

"[r]esults from these data suggest that swimmers generating higher than average peak forces were more likely to produce a better overall start performance than those who produced forces lower than the average, for this population of athletes (Slawson 2013)".

Now, some may speculate that improving peak force (via jumping or resistance training) will improve starting performance, but this study does not imply this. All this study suggests is those who have generate higher than average peak forces are correlated with greater starts on the OSB11.



Further Reading
Painful Arc and External Rotation Predict Rotator Cuff Disease
Many swim coaches want nothing to do with shoulder injuries, but this simply isn't an option when shoulder pain is estimated at 60% in the sport. A recent systematic review looked at predictors of rotator cuff disease and found: 
"[a] positive painful arc test result and a positive external rotation resistance test result were the most accurate findings for detecting RCD [rotator cuff disease], whereas the presence of a positive lag test (external or internal rotation) result was most accurate for diagnosis of a full-thickness rotator cuff tear (Hermas 2013)."

These simple tests can be performed before a coach in the beginning of a season. If you want to help your swimmers and learn other troubleshooting methods, pre-order Swim Sci Troubleshooting!

Muscular Fatigue is Individual
The principal of individuality is essential for maximal improvement. This principal is gaining popularity for energy system training, but also must be applied for biomechanics and fatigue.

In this study:
"[s]urface electromyography signals were collected from the flexor carpi radialis, biceps brachii, triceps brachii, pectoralis major, upper trapezius, tibialis anterior, biceps femoris, and rectus femoris muscles of 10 international-level swimmers; 4 underwater cameras were used for kinematic analysis. In addition, blood lactate was measured before and after the test using capillary blood samples (Figueiredo 2013)." 

The author concludes:
"The changes in stroke parameters were associated with an increase in integrated electromyography (20%-25%) and a decrease in spectral parameters (40%-60%) for all of the upper-limb muscles, indicating the reaching of submaximal fatigue. The fatigue process did not occur regularly during the 8 laps of the 200 m but was specific for each muscle and each subject. Lower-limb muscles did not present signals of fatigue, confirming their lower contribution to swimming propulsion. The test was conducted to individualize the training process to each muscle and each subject (Figueiredo 2013)".

This study adds evidence to a few features:
  1. The principle of individuality
  2. The low contribution of the lower-limbs to propulsion (perhaps not at all (Rushall 2013)
  3. The importance of staying "relaxed" during fatigue, since lactate is correlated with increased electromyographic activity
Further Reading
References:
  1. Magnus CR, Arnold CM, Johnston G, Dal-Bello Haas V, Basran J, Krentz JR, Farthing JP.Cross-education for improving strength and mobility after distal radius fractures: a randomized controlled trial. Arch Phys Med Rehabil. 2013 Jul;94(7):1247-55. doi: 10.1016/j.apmr.2013.03.005. Epub 2013 Mar 22.
  2. Slawson SEConway PPCossor JChakravorti NWest AA. The categorisation of swimming start performance with reference to force generation on the main block and footrest components of the Omega OSB11 start blocks. J Sports Sci. 2013;31(5):468-78. doi: 10.1080/02640414.2012.736631. Epub 2012 Nov 7.
  3. Hermans J, Luime JJ, Meuffels DE, Reijman M, Simel DL, Bierma-Zeinstra SM.Does this patient with shoulder pain have rotator cuff disease?: The Rational Clinical Examination systematic review .JAMA. 2013 Aug 28;310(8):837-47. doi: 10.1001/jama.2013.276187.
  4. Figueiredo P, Rouard A, Vilas-Boas JP, Fernandes RJUpper- and lower-limb muscular fatigue during the 200-m front crawl. Appl Physiol Nutr Metab. 2013 Jul;38(7):716-24. doi: 10.1139/apnm-2012-0263. Epub 2013 Feb 4.
  5. Rushall BS. CURRENT SWIMMING TECHNIQUES: THE PHYSICS OF MOVEMENTS AND OBSERVATIONS OF CHAMPIONS Swimming Science Bulletin, 44, 3 pp. 2012. [http://coachsci.sdsu.edu/swim/bullets/Current44.pdf]
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 founder of Mullen Physical Therapy, the Center of Optimal Restoration, head strength coach at Santa Clara Swim Club, creator of the Swimmer's Shoulder System, and chief editor of the Swimming Science Research Review.

Weekly Round-up

  1. How sleep helps brain learn motor task.
  2. Fatigue shifts and scatters heart rate variability in elite endurance athletes. - by Dr. Schmitt
  3. The development of peripheral fatigue and short-term recovery during self-paced high-intensity exercise. - by Dr. Froyd
  4. Postural control and low back pain in elite athletes comparison of static balance in elite athletes with and without low back pain. - by Dr. Oyarzo
  5. Virtual swimming--breaststroke body movements facilitate vection. - by Dr. Seno
  6. Symmetry of support scull and vertical position stability in synchronized swimming. - by Dr. Winiarski
  7. Is bone tissue really affected by swimming? A systematic review.- by Gómez-Bruton
  8. Effect of gene polymorphisms on the mechanical properties of human tendon structures. - by Dr. Kubo
  9. Relation between efficiency and energy cost with coordination in aquatic locomotion. - by Dr. Figueiredo
  10. Is There a Minimum Intensity Threshold for Resistance Training-Induced Hypertrophic Adaptations? - by Brad Schoenfeld
  11. The Temporal Profile of Postactivation Potentiation is related to Strength Level. - by Dr. Seitz
  12. Athletes and novices are differently capable to recognize feint and non-feint actions. - by Dr. Güldenpenning 
  13. Effects of betaine on body composition, performance, and homocysteine thiolactone. - by Dr. Cholewa
  14. Fructose-Maltodextrin Ratio Governs Exogenous and Other CHO Oxidation and Performance. - by Dr. O'Brien
  15. Sports drink consumption and diet of children involved in organized sport. - by Dr. Tomlin
  16. Which exercises target the gluteal muscles while minimizing activation of the tensor fascia lata? Electromyographic assessment using fine-wire electrodes. - by Dr. Selkowitz
  17. Scapular Kinematics and Shoulder Elevation in a Traditional Push-Up. - by Dr. Suprak

Friday Interview: Benjamin Pageaux Discusses Mental Fatigue and Exercise Performance

1. Please introduce yourself to the readers (how you started in the profession, education, credentials, experience, etc.).
My name is Benjamin Pageaux, I am PhD student in the School of Sport and Exercise Sciences in the University of Kent (UK) under supervision of Prof. Samuele Marcora. Before arriving in the UK, I received my BSc in 2008 and MSc in 2011 at the Faculté des Sports in Dijon under supervision of Dr. Romuald Lepers. My Phd topic is on the perception of effort and endurance performance.

2. You recently published an article on mental exhaustion and fatigue, could you first explain the theories of how mental fatigue effects performance?
In 2009 Prof. Marcora demonstrated for the first time that mental fatigue negatively impact endurance performance. In this study, subjects performed a time to exhaustion on the bike at 80% of their peak power output after either completion of a mentally fatiguing task (computer task) or a control task (movie). Performance in the mental fatigue condition dropped by 15% compared to control condition, and thus for same cardiorespiratory and metabolic alterations induced by the cycling exercise. The only difference between conditions was the higher perception of effort during cycling experienced under mental fatigue.

The recent study we published is very similar, except that we performed an isometric contraction until exhaustion with the quadriceps muscles and tested the neuromuscular system. We tested the neuromuscular system to investigate if the decrease in endurance performance could be due to the inability of the subject to produce maximal force.

3. What were the pertinent findings in your study?
Our study confirms the negative impact of mental fatigue on endurance performance. We also found a decrease of around 15% in endurance performance associated with a higher perception of effort. The main finding is that the decrease in endurance performance is not associated with the ability of the subject to produce the maximal force prior to exercise. Central fatigue corresponds to a decrease in the ability of the central nervous system to fully recruit the working muscle fibers and produce the maximal force. Mental fatigue and central fatigue are often mistaken, and it was expected a decrease in maximal muscle activation with mental fatigue. However it is not the case, it means that when subjects are mentally fatigued they keep the ability of maximally recruiting the working muscles. Finally the extent of muscle fatigue at exhaustion is similar between conditions.

Basically, mental fatigue impairs endurance performance independently of any responses of cardiorespiratory, metabolic and neuromuscular systems to the exercise. Both studies suggest that mental fatigue impairs the central processing (in the brain) involved in perception of effort generation, Perception of effort seems to be a key determinant of endurance performance.

4. How do you think mental fatigue effects sprint/short burst exercise compared to aerobic exercise?
According to our results, maximal force production seems to be not affected by mental fatigue. Our subjects, after performing the mentally fatiguing tasks, where still able to produce the same force as before the cognitive task. Meaning that when you are mentally fatigued you are still able to push as hard as you can. And this seems to be confirmed with other studies we are carrying out. However sprint repeatability during whole-body exercise I don't know.

5. If someone is mentally fatigued, what steps should they take to prevent performance impairments?
Sleep deprivation is known to induce as well a subjective feeling of tiredness and decrease endurance performance via a higher perception of effort. So I would suggest ensuring a sufficient amount of sleep before an event. Research on caffeine also demonstrated that caffeine ingestion is able to counteract the negative effect of mental fatigue on cognitive performance.

6. Do exams or midterms, many coaches have flexible schedules and easier workouts. Do you think this is necessary?
I think independently of training and season planification, the trust between coaches and athletes is the key factor for good workouts. It is clear that psychological factors, especially motivation, can impact performance, and this has to be taking into account by coaches. If coaches feel the need to do perform easier workout to avoid any burn-out syndrom for the athlete, yes I think it is definitely necessary.

7. Is there a maximum volume of training you'd recommend for someone under extreme mental fatigue? Also, how can this be determined/individualized?
To be honest I don't know. It is I think hard to determine this state of mental fatigue on a day to day basis. If a training occurs end of the day, depending on what happened before it, the psychological state of the athlete can change and that could impair the workout. Again, I think the trust before coaches and athletes is very important. How can we individualised it ? I would say asking the rate of perceived exertion (RPE scale) of the athlete during the workout. If the effort is rated clearly higher than usual for a same intensity, that could be a good indicator for the coach to decrease the intensity of the workout. But again this could not be done without a good relation coach-athlete and a well motivated athlete.

8. What research or projects are you currently working on or should we look from you in the future?
With Prof. Marcora and Dr. Lepers, we are working on the mechanisms involved in perception of effort and its impact on endurance performance. We are still working on the impact of mental fatigue on performance, and especially on time trial performance, that is more relevant to competition situation, when the athletes can choose their own pacing. Also trying to identify how muscle fatigue could impact perception of effort and performance is definitely something of interest.

Many thanks John for your interest in our study, and I hope it was of interest for the readers of Swimming Science as well.

Brief Swimming Review Volume 1 Edition 6

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

Altitude Training Improves Body Composition in Swimmers 
We've discussed Chia's work on Swimming Science previously (Altitude training for weight loss?; Friday Interview: Dr. Chia-Hua Kuo and Dr. Futoshi Ogita; Friday Interview: Dr. Chia-Hua Kuo), but he once again released a paper in the Chinese Journal of Physiology interpreting the results of his research on hypoxia reducing body fat in swimmers.

"The purpose of the study was to examine changes in body composition after altitude hypoxia exposure and the role of blood distribution to the skeletal muscle in swimmers. With a constant training volume of 12.3 km/day, young male swimmers (N = 10, 14.8 ± 0.5 years) moved from sea-level to a higher altitude of 2,300 meters (Chia 2013)".

Chia et al. (2013) found the altitude training group had a reduction of body fat mass by 1.7 kg and an increase in lean body mass of 0.8 kg. Arterial oxygen saturation significantly decreased with an increase in plasma lactate during hypoxic training. Increases in total hemoglobin concentration and sympathetic activity also occurred with hypoxic training.

This team concludes"the present study provides evidence that increased blood distribution to the skeletal muscle under postprandial condition may contribute to the reciprocally increased muscle mass and decreased body mass after a 3-week altitude exposure in swimmers (Chia 2013)". However, one could argue an increase in sympathetic nervous system activity increases fat use and total hemoglobin concentration. Unfortunately, this theory would not explain the increase in lean body mass (unless the sympathetic increase simply caused an increase in training capacity).

Practical Implication: High altitude training appears to improve body composition in swimmers, unfortunately the use for performance benefits still lacks support.

Effects of Fatigue During Women 100-m Fly 

It is well established differences in swimming velocity alter stroke biomechanics. However, the specific alterations during each stroke is not well known. This study analyzed the effects of kinematic changes in women performing maximal and submaximal 100-m butterfly bouts.

de Jesus (2012) note: "[v]elocity, stroke length, stroke frequency were lower for 4th than 1st lap, at both intensities. Dropped elbow and foot vertical amplitude of 1st and 2nd downbeats were higher for 4th than 1st lap, at both intensities. At submaximal and maximal intensity, swimmers spent more time during push and recovery phases. At submaximal intensity, swimmers experienced fewer difficulties to cope with fatigue between 1st and 4th lap, which allowed the maintenance of intracyclic velocity variation. However, at maximal intensity, swimmers were probably more fatigued and, as a consequence, less mechanically efficient, showing an increase in intracyclic velocity variation."

Practical Implication: Unfortunately, this reviewer does not have the full paper for a complete review, since the abstract is rather vague and somewhat obvious. Let me know if anyone has the full work!

Lat Stiffness Alters Scapular Kinematics

Launder (2013) measured nineteen NCAA Division III swimmers' (M=7, F=12; ~18.8 years) latissimus dorsi stiffness. The results showed latissimus dorsi stiffness had "moderate-to-good relationships with increased scapular upward rotation (r > -0.63, P < 0.002) and posterior tilt (r > -0.62, P < 0.004) at all four angles of humeral elevation. Increased latissimus dorsi stiffness also showed moderate-to-good relationships with decreased scapular internal rotation at humeral elevation angles of 60° (r = 0.47, P = 0.03) and 90° (r = 0.54, P = 0.01). (Launder 2013)".

Practical Implication: Many rehabilitation specialist find those with shoulder pain had decreased scapular upward rotation and posterior tilt. These results contradict those views, requiring confirming studies. Nonetheless, coaches should assess latissimus stiffness and scapular kinematics.

References:

  1. Chia M, Liao CA, Huang CY, Lee WC, Hou CW, Yu SH, Harris MB, Hsu TS, Lee SD, Kuo H.Reducing body fat with altitude hypoxia training in swimmers: role of blood perfusion to skeletal muscles. Chin J Physiol. 2013 Feb 28;56(1):18-25. doi: 10.4077/CJP.2013.BAA071.
  2. de Jesus Kde Jesus KFigueiredo PAGonçalves PVilas-Boas JPFernandes RJ. Effects of fatigue on kinematical parameters during submaximal and maximal 100-m butterfly bouts. J Appl Biomech. 2012 Nov;28(5):599-607. Epub 2012 May 8.
  3. Laudner KG, Williams JG.The relationship between latissimus dorsi stiffness and altered scapular kinematics among asymptomatic collegiate swimmers. Phys Ther Sport. 2013 Feb;14(1):50-3. doi: 10.1016/j.ptsp.2012.02.007. Epub 2012 Jul 28.
By Dr. G. John Mullen received his Doctorate in Physical Therapy from the University of Southern California and a Bachelor of Science of Health from Purdue University. He is the founder of Mullen Physical Therapy, the Center of Optimal Restoration, head strength coach at Santa Clara Swim Club, creator of the Swimmer's Shoulder System, and chief editor of the Swimming Science Research Review.