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.
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fact, a recent study of us, unpublished yet, demonstrated that 1-hour fencing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.
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.
As I recently wrote in aerobic exercise improves pain tolerance, many people believe they have high pain tolerances. I always find this comment entertaining, especially in the general population, as pain tolerance is unrelated to masculinity or any egotistical belief. In fact (as you'll see below), having a high pain tolerance could be harmful, as pain signals something is harmful. 
The researchers noted the national team had a preference for the word
“tingling” to describe ischemic pain. Pain threshold scores were not different
between the three groups. The national squad showed highly significant
differences in pain tolerance from the other two groups. Men and women did not
significantly differ. Pain tolerance scores correlated with intensity of
training.
