Hi All
Last month
I mentioned that Asta and I had recently been gallivanting around the world and
that we had really enjoyed ourselves. If you are interested, I have placed a
few images on Facebook for you to take a look at if you are interested. There
are four sets,
One of the
following articles refers to fast- and slow-twitch muscle fibres. I guess most
of you will have heard about this part of our muscle structure and if you are a
practising athlete, you will have already categorised yourself into one of the
two main groups of twitch-fibre types. If you are a sprinter, you have selected
this category because your body has indicated that you can run fast, and to do
this, you needed to have fast-twitch fibres. Training can improve your speed by
working on the neuro-patterns of your muscles – but what if you are a slower
type of animal.
You don’t
have to relegate your running to the tortoise ranks and forever be chugging
along at the rear of the group. Training involving some “speed” work can
improve how fast you can run.
Although
we generally think of there only being the two types of twitch fibres, there is
an intermediary group of fast twitch fibres that can be modified to assist the
basic bank of slow-twitch fibres. What this boils down to, is that a slow
runner can modify some fast-twitch fibres to be more anaerobically capable and
to add some speed to the distance-running capabilities of the runner.
To achieve
this process, a balanced training programme that involves specific speed-work
aimed at recruiting/transforming some of these fast-twitch fibres can produce a
faster marathon/10k without causing you too much discomfort. All of your
training schedules should involve some sort of speed component. It is also
beneficial for the aging sector (like me) as it helps to overcome the muscle
atrophy that begins to take place as testosterone (yes ladies, you too!)
decreases with age. Simply adding one relatively short training session at a
higher than normal intensity each week may well see you producing better race
times – and may also help with other aspects of your day-to-day life.
Keep up
the good work.
Cheers
PROGRAM
FITNESS
If you should be aware of someone who might benefit from being on a
running or walking exercise program, please get them to log on to www.profitness.net.nz for more information on how I may be
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Muscles and muscle
fibres
What are muscle fibres?
Muscles – like the rest of the body – are made up of cells, and in
muscles these cells form muscle fibres.
Muscle fibres contract to create
movement after receiving electrical signals from the brain – a chemical
reaction then occurs in the muscle to create muscular activity. Depending on
the sport or fitness activity, this chemical reaction can create long- or short-lasting
energy (as in the case of a marathon run or a tennis serve respectively).
The specifics of slow-twitch muscle fibres.
Slow-twitch muscle fibres are
endurance fibres.
What makes a muscle slow or
fast? This has a lot to do with the number of slow- and fast-twitch muscle
fibres a muscle has, and the way these fibres are trained. The more slow-twitch
fibres there are, the better the muscle will be at providing lasting energy –
see table 1 for examples of the percentages of slow-twitch fibres in the shoulder
of selected sports participants. Conversely, the more fast-twitch fibres, the
better the muscle will be at generating speed and power. You can change the
proportion of the fibres between fast and slow, with the prolonged right
training (although research indicates that these changes are not
permanent).
Twitch rate
Muscles twitch – basically this reflects their speed of contraction when
they are stimulated. Slow-twitch fibres do not have a very fast twitch rate
compared to fast-twitch fibres, because they are not designed for speed.
Twitch rate per
second
Slow-twitch muscle fibres 10-30
Fast-twitch 30-70
Slow-twitch fibres have a
good blood supply, which greatly assists their ability to generate aerobic
energy (that is, energy that relies on oxygen to fuel the chemical reactions
going on within the muscles that provide this lasting energy). This oxygen
supply capability can be enhanced by the right training.
Slow-twitch fibres can also be called ‘red’ fibres
because of their ample blood supply.
Unlike fast-twitch fibre,
slow-twitch fibre is less likely to increase muscle size when trained via
endurance activities (or weight training). However, well-trained endurance
athletes will have slow-twitch fibres that are slightly enlarged, in comparison
to non- athletes and speed or power athletes, such as sprinters. But the most
‘noticeable’ endurance training effects occur inside the muscle and manifest
themselves on the road, track or water in terms of enhanced endurance ability.
Table 1 displays how slow-twitch
fibres can be developed through relevant endurance training. The more endurance
training an athlete undertakes, the more slow-twitch muscle fibres they will
develop. Compare the figures in the table with non-athletes, who would have
around 45-55% slow-twitch fibres in their arms and across their body.
Slow-twitch muscle fibre’s
response to endurance training:
- Improved aerobic capacity
- An increase in capillary
density. Capillaries are oxygen-carrying highways, and the more
capillaries there are in a muscle, the greater the potential for aerobic
energy creation
- The more endurance-trained a
muscle is, the greater its stock of enzymes relevant to other specific
muscular energy creation processes – notably the Krebs cycle. The Krebs
cycle is a chemical process that takes place in muscles. Using an analogy,
it’s a bit like having your own oil refinery in your car, that keeps
producing (cheap!) fuel. In the body’s case, this equally crucial fuel is
adenosine triphosphate (ATP). ATP is the key energy-producing chemical in
the body.
Table 1: Percentage of
slow-twitch fibre in deltoid (shoulder) muscle in males and selected sports
|
Endurance
athlete |
Percentage
of slow-twitch fibre in deltoid (shoulder) muscle – males |
|
Canoeist |
71% |
|
Swimmer |
67% |
|
Triathlete |
60% |
Further characteristics
of slow-twitch fibre
Muscle fibres – whether slow or
fast – are bundled together to form more powerful units (these are known as
motor units). They can be equated to cogs in a machine that synchronise with
each other to produce, in this case, muscular power. Depending on fibre type,
these motor units do not mesh in the same way.
Slow-twitch muscle fibres are recruited synchronously.
This means that their motor units
work together to produce movement – one ‘cog’ turns another – and all at the
same time. This contrasts with fast-twitch fibre, whose motor unit cogs are
recruited asynchronously.
Basically, the smallest cogs (ie,
the slow-twitch fibres’ smaller motor units) turn first and then the larger
ones (fast-twitch fibres) only once the athlete mentally stimulates them to do
so. This can be achieved by psyching oneself up and becoming aggressive and
explains why, for example, it is difficult to lift a heavy weight without being
in the zone.
With slow-twitch fibres, less
mental effort is required to fire them, until the athlete is fatigued. If you
don’t put a lot of mental effort in when jumping, for example, you won’t jump
that high (and you’ll be using your slow-twitch and intermediate fast-twitch
fibres). To jump high you have to engage the larger, fast-twitch motor units,
and this needs greater mental effort.
Slow-twitch muscle fibres provide a
stabilising function within muscles
The percentage of slow-twitch and
fast-twitch muscles fibres varies between muscles. The gastrocnemius – the
larger of the calf muscles – has a greater percentage of fast-twitch fibres in
comparison to the smaller soleus. Balance and stability work tends to target
the muscles with the greater proportion of slow-twitch muscle fibres, whereas
those with more fast-twitch fibres are more power- and movement-orientated.
Thus a single leg balance, from a standing-on-tiptoes position, will emphasise
the slow-twitch fibres of the soleus, while a straight leg jump will primarily
recruit the fast-twitch muscle fibres of the gastrocnemius.
This article was taken from the Peak
Performance newsletter, the number one source of sports science,
training and research. Click here to access these articles
as soon as they are released to maximise your
performance.
***************************************************
Making Weight For a Race
by Ben Greenfield on September 22, 2009 in Health & Nutrition, Triathlon Training
It may not be the ideal
situation, but it's happened to just about every triathlete, typically about
3-5 weeks before your big race. You step on the scale and...You’re heavy.
Really heavy.
You panic. You're stuck between a
rock and a hard place, because you can't just go on a very low calorie diet
combined with even more training. Your race plan would suffer, you'd lose lean
muscle, and you likely would get sick from a weakened immune system and poor
recovery.
So what do you do?
In the fitness world, where I
spend quite a bit of time working with people who want to "lose fat but
not lose muscle", there are little tricks that I incorporate into the
weekly routine that will equal significant gains in weight loss and fat
burning, without sacrificing lean muscle mass. Over years of training hundreds
of clients and athletes, I've discovered 3 of these key fat burning techniques
that achieve the best results.
Here they are:
1) One to two days per week,
complete a long, slow cardio session in your fat-burning heart rate zone (about
50-60% intensity). Preferably do this in the morning before breakfast.
During this session, fuel with
just 100 calories per hr (small people and females) or 150 calories per hour
(large people and males). This session should be 1.5 hour minimum and up to 3
hours maximum. This is because a) the enzymes responsible for burning fat
during exercise must be trained to work at a high efficiency, and this only
occurs during extended, low-intensity cardio sessions that stimulate the same
muscle over and over again; b) too long in an "unfed" or minimally
fed state will lead to high cortisol levels and an unhealthy stress response.
Do no more than two of these sessions per week, especially if you are building
up to a race.
2) At least 2 days/week, complete
a high intensity non-aerobic interval training sessions of 30 minutes, that
includes at least 10 minutes spent above an 8 on an exertional scale of 1-10.
There is a crucial paradox in
exercise and in triathlon training. While exertion at lower intensities will
burn primarily fat as a fuel, you actually burn *less* total fat than compared
with exercise at higher intensities. Why is this? Because when you exercise at
a lower intensity, you burn significantly fewer calories. For example, you may
burn 70% fat and 30% carbohydrate during low intensity exercise at 300 calories
per hour. That's 210 calories of fat per hour. But at a higher intensity of,
say 900 calories per hour, you may burn 30% fat and 70% carbohydrate. That's
270 calories of fat per hour. There are also huge implications with intense
workouts, primarily an increase in fat-burning hormones, post-exercise
metabolic rate, and lean muscle tissue building. Interval training is the ideal
way to achieve these type of sessions and are comprised of hard efforts at a
high intensity separated by rest periods at a low intensity. This should fit in
well with your race plan. These workouts must be well-fueled and not performed
on an empty stomach or with low blood sugar.
3) At least 5 days/week complete
20 minutes of aerobic, fat-burning cardio prior to breakfast.
When you wake up in the morning,
your body has burned through a significant portion of the liver's carbohydrate
stores. You can activate fat mobilization and burning early in the day by
completing a light cardio session when you are in this "fasted"
state. More is not better in this case. If you go for a 2 hour run, you'll
return completely depleted and in fat-storage mode. Instead, go light and easy
for a short period of time, then consume a healthy and complex breakfast that
includes good fats, complete proteins, slow digesting carbohydrates, and fiber.
As you employ these three strategies, ensure that you are consuming adequate
protein intake to avoid lean muscle mass wasting. For most triathletes leading
up to a race, I recommend this amount of protein to be 1.2-1.4 grams per pound
of body weight. The ultimate goal is to "treat your body well" by
fueling it adequately for the high intensity sessions, then work low intensity,
minimally fueled fat burning sessions in throughout the week.
For more on weight loss and
boosting your calorie burning with special herbs, foods, dietary secrets and
tricks, you may want to head over to the website http://www.100waystoboostyourmetabolism.com
, where there is an instantly downloadable book that is jam-packed with
metabolic insider tips!
Good luck!
******************************************************
Preventing Loss of Muscle Strength with
Aging
Taken from:
Dr. Gabe Mirkin's Fitness and Health E-Zine:
As you age, you lose muscle size and strength much faster than you lose
endurance or coordination. Researchers at the
Insulin drives amino acids into muscles to help them recover from exercise and
maintain their size. Researchers traced radioactive
amino acids and showed that insulin drives the amino acids into muscles much
more effectively in 25-year-olds than in 60-year-olds. They also showed that
the blood flow in younger people's legs is much greater and supplies far more
nutrients and hormones. However, three exercise sessions per week over 20 weeks
markedly increased blood flow in the legs of the older subjects, enough to
reverse muscle wasting.
People of all ages can use this information to help themselves become stronger.
Athletes in all sports train by stressing and recovering. They take a hard
workout, damage their muscles, feel sore the next morning, and then take easy
workouts until the
muscles heal and the soreness goes away. The athlete who can recover the
fastest can do the most intense workouts and gain the most
strength.
Eating a high carbohydrate-high protein meal within half an hour after
finishing a workout raises insulin levels, increases amino acid absorption into
muscle and hastens recovery (Journal of Applied Physiology, May 2009). The
carbohydrates cause a high rise in blood sugar that causes the pancreas to
release insulin. Insulin drives the protein building blocks (amino acids) in
the meal into muscle cells to hasten healing from intense workouts.
Muscles are extraordinarily sensitive to insulin during exercise and for up to
a half hour after finishing exercise, so the fastest way to recover is to eat
protein- and carbohydrate-rich foods during the last part of your workout or
within half an hour after you finish.
Here's how Diana and I (ages 67 and 74) use this information on insulin
sensitivity.
We ride hard and fast for about 20 miles on
Tuesdays, Thursdays and Saturdays. On our recovery days, we ride slowly for one
to three hours. Mid-day we go to a buffet restaurant
and eat a large meal with fish, shrimp, vegetables and other sources of protein
and carbohydrates. After eating, we ride slowly for one or two more hours.
Riding before we eat makes our muscles very sensitive to insulin. This causes
insulin to drive amino acids rapidly into our muscles and help them recover
faster. Riding after we eat helps us to avoid a high rise in blood sugar that
damages
cells. You can use either plant or animal sources of protein; both contain all
of the essential amino acids necessary for cell growth.
***************************************************
A young man and an old man were fishing on a pier. The young man started
telling the old one that the night before he caught a trout that was over 3 1/2
foot long.
The old man replied "Oh yea, well I was here 2 nights ago and
I hooked something huge. After a 30 minute fight I finally got it up and it was
an old lantern and the thing was still lit."
The young man said "You're lying. I can't believe that."
Then the old man said "I'll tell you what, you knock a couple
of foot off your trout and I'll blow out my lantern."
BLOOD DONATIONS
Endurance athletes should give
blood but not before a race. Giving blood will reduce performance significantly
if not advanced-planned and factored correctly within one's training protocols.
When an athlete donates blood, 500 milliliters of fluid is lost, approximately
70 grams of hemoglobin (='s 220 mg.Iron) and millions of red blood cells. The
fluid loss comes back within a few hours, but restoration of the red blood
cells takes several weeks. If you are iron-poor, it takes even
longer, and is a medical consideration since a few high-mileage ultra-athletes
tend towards iron-poverty from training demands.
A blood donation consists of 500 ml, a little over 16 fluid ounces. The loss of
70 grams of hemoglobin[220 mg. of iron] alone takes at least
3 weeks to replace in the healthiest of athletes, but may not fully rebound (till) nearly 6 weeks after the
donation. Exercise should be avoided
the day blood is donated, while competitive maximal efforts should be avoided
for 6 weeks. Christensen & Christensen [1978] measured athletic
performances post-blood donations, reporting a decrease in VO2 Max of -10 to
-15%. Most of us do not want to give away 10-15% to our competitors; it's like
riding with only half the air pressure in your tires, making for a long and
slow effort at best. Athletes should have blood haemoglobin and ferritin levels
checked prior to donating blood. It is also suggested to avoid both intense
impact or prolonged endurance running 5 days prior to the donation and up to 6
weeks post-donation.
Noakes [1991] suggests it is safe to donate blood if ferritin levels are above
60 ng/ml and the donating athlete has not run hard for 5 days. He also suggests
NOT giving blood if hemoglobin levels are low, i.e. less than 14.5 g/100ml.
REFERENCES
*** Christensen, T., Christensen, G., The effects of blood loss on the
performance of physical exercise, European Journal of Applied Physiology
1978; 39:17-25
*** Noakes, T.D., THE LORE OF RUNNING, Leisure Press, Champaign, Ill.
1991:695.
************************
Cheers