Lactate is a Scapegoat for Fatigue

In swimming and sports, many coaches associate lactate and lactic acid with fatigue. Unfortunately, lactate is a scapegoat! During a fatiguing event, many physiological processes occur (and increase in lactate being one), yet little is mentioned about the other processes. 

Lactate may get a bad wrap, as it is currently the standard for measuring fatigue, but lactate is likely associated, not the cause of fatigue. For swimming, Dr. Ernest Maglischo has wrote an excellent piece about the pitfalls in the lactate theory. He even breaks down many of the possible causes of fatigue (find this article in VO2max is not Important for Competitive Swimmers).

One point Dr. Maglischo discusses is how lactate is actually a substrate used to create energy. This small piece of the puzzle is the topic of today. 

A recent study from the University of Hull in the United Kingdom looked at the effects of giving cyclist sodium bicarbonate (baking soda) or lactate prior to a 40-km cycling time trial. This study by Northgraves et. al. (2013) had 
"[s]even recreationally active males (age, 22.3 ± 3.3 years; height, 182.5 ± 6.5 cm; body mass, 79.2 ± 6.3 kg) completed five 40 km cycling time trials, including a familiarization trial in a randomized blind double placebo design. Subjects ingested either 1.) 300 mg per kg body mass NaHCO3 (BICARB), 2.) 45 mg per kg sodium chloride (PL-BICARB) as the placebo for the NaHCO3 trial, 3.) 21.5 mg per kg body mass lactate supplement (LACTATE) and 4.) plain flour as the placebo for the lactate trial (PL-LACTATE) 60 minutes before exercise."

The results of this study showed no differences in performance between groups, only a higher heart rate in the lactate supplementation group. Though this is one study, it highly suggests an increase in lactate does not cause fatigue (no improve performance). Therefore, more variables are involved in the role of fatigue. This multivariable process requires much more research, but it seems lactate is not the main culprit of fatigue.

Reference

1. Northgraves MJ, Peart DJ, Jordan C, Vince RV.Effect of lactate supplementation and sodium bicarbonate on 40 km cycling time trial performance. J Strength Cond Res. 2013 May 8. [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. He is the founder of the Center of Optimal Restoration, head strength coach at Santa Clara Swim Club, creator of the Swimmer's Shoulder System, and chief editor of the Swimming Science Research Review.

Reliability Rating of Perceived Exertion in Swimming. Part II

The best swimmers are renowned for knowing their bodies well.  Whether it’s an internal clock to hit exact splits, or understanding the limits of one’s physical capacity, there’s no doubt that internal perception is a valued athletic skill.  In general, ratings of perceived exertion have been shown to correlate with actual output both in swimming and other sports as we noted in this prior post on Reliability Rating of Perceived Exertion in Swimming.     

Most research on perceived exertion has looked at the correlation between subjective assessment and objective data of specific exertion levels.  If a swimmer rates their effort as an 18 on the 20 point RPE scale, we’d expert their actual output to be near 90% physical capacity.  One recent study (Barroso 2013) examined perceived exertion at the workout level among young swimmers. 

Barroso (2013) asked the simple question: how did swimmers perceive whole workouts as compared with their coaches’ perceptions?   Coaches rated the session before the workout, and swimmers were asked to rate the workout 30 minutes after.   Workouts could be classified as easy (RPE less than 3), moderate (3-5), and difficult (5 or greater).  For analysis, authors divided athletes into three age brackets: 11-12, 13-14, 15-16.   

Results indicated that age and swimming experience increased the correlation between coach and athlete ratings of perceived exertion.  This finding should not be surprising as we’d anticipate age, experience, and maturity to improve this area.   It’s also likely that knowing your body is an important trait for swimming success and that attrition may remove swimmers who lack this skill. 

Though the correlations improved with age, they were not perfectly aligned….younger swimmers (11-12, and 13-14) rated training intensity differently from coaches in all three categories (easy, moderate and difficult) while the older group rated workouts differently in only the “difficult” category.  Swimmers and coaches perceived workouts more closely as swimmers got older, but we all know from experience that each swimmer is different.  A similar inconsistency was present in Wallace (2006) in which coaches’ RPE estimates were lower than athletes for low intensity swimming, but higher than athletes for high intensity swimming.      

Recently, Dr. John proposed that swimmers be given chances to self-regulate workload in Do You Want to Do Another?.  “[E]ncouraging swimmers to do more is a method of increasing internal motivation. Moreover, allowing swimmers to determine the volume of their training associates swimming volume with success.”  Along with improving motivation, it may also reveal whether coaches and athletes perceive workouts the same. 

Further, based on the correlation between age and coach/athlete RPE values, it would also suggest that self-regulation can be administered as a privilege to swimmers as they age and show the maturity to handle the responsibility. 

Practical Implication

Despite all the fancy ways to quantify workload, subjective perception should not be ignored.  It’s critical that coach and athlete are on the same page.  Coach Sweetenham has noted that athletes often know the coach better than the coach knows the athlete, as the coaching staff is usually far outnumbered by swimmers.  The athlete only has to know a few coaches, but the coach must know dozens, if not hundreds of athletes.  What we as coaches see as “hard” or “easy” might diverge from what the athlete perceives, particularly at the younger ages.     

References

1. Barroso R, Cardoso RK, do Carmo EC, Tricoli V.  Perceived Exertion in Coaches and Young Swimmers With Different Training Experience.  Int J Sports Physiol Perform. 2013 Apr 23. [Epub ahead of print]
2. Wallace LK, Slattery KM, Coutts AJ. The ecological validity and application of the session-RPE method for quantifying training loads in swimming. J Strength Cond Res. 2009 Jan;23(1):33-8. 

By Allan Phillips. Allan and his wife Katherine are heavily involved in the strength and conditioning community, for more information refer to Pike Athletics.

Weekly Round-up

1. 5 Traits of Successful Athletes
2. Should Force, Power, and RFD Outputs be Primary Considerations for Exercise Selection?

 

 

Friday Interview: Takanobu Okamoto Ph D Discusses Foam Rolling and Arterial Mobility

1. Please introduce yourself to the readers (how you started in the profession, education, credentials, experience, etc.).
I'm Takanobu Okamoto, professor of nippon sport science university. I'm scientist of exercise physiology.

2. You recently published an article on arterial function and foam rolling, could you briefly explain your pertinent findings?
The purpose of this study was to investigate the acute effect of self-myofascial release using a foam roller on arterial stiffness and vascular endothelial function. We examined the effects of this technique on the adductors, hamstrings, quadriceps, iliotibial band and upper back including trapezius. Self-myofascial release (SMR) using a foam roller reduced arterial stiffness and improved vascular endothelial function.
 

3. Based on the findings, how do you think athletes should use foam rolls?
Because SMR reduces arterial stiffness and improves vascular endothelial function, it might be an effective component of a warm-up and/or cool down. Therefore, this technique might aid conditioning and/or promote cardiovascular health in athletes.

4. Do you think there is any difference between foam rolls, baseballs, or tennis balls?
I think that there is not great difference between foam rolls, baseballs, or tennis balls.

5. How long can someone perform this self soft tissue? Is there a point of diminishing return?
About 1 min. I think that there is not a point of diminishing return.

6. With improved range of motion and now arterial mobility, what other benefits may self soft tissue mobility have?
Flexibility of muscle, joint and/or tendon may improve.

7. Any possible negative effects (lying on a nerve)?
If user emphasize too much, muscle or nerve may damage.

8. Who is doing the most interesting research on foam rolling in the field? What are they doing? Scientific research to support SMR using a foam roller is scanty. Recently, two studies were published.

1. Healey KC, Hatfield DL, Blanpied P, Dorfman LR, Riebe D. The Effects of Myofascial Release with Foam Rolling on Performance. J Strength Cond Res. 2013 Apr 12. [Epub ahead of print]
2. MacDonald GZ, Penney MD, Mullaley ME, Cuconato AL, Drake CD, Behm DG, Button DC. An acute bout of self-myofascial release increases range of motion without a subsequent decrease in muscle activation or force. J Strength Cond Res. 2013 Mar;27(3):812-21.

10. What research or projects are you currently working on or should we look from you in the future?
I am studying on relationship between exercise training arterial function.

I want to apply the result to condition.

Thanks Dr. Okamoto