By Rob Wilkins
Health News: By Rob WIlkins
STRENGTH DECREASES WITH AGE
The aging process
is characterized by a reduction of the physical capacities of coordination,
flexibility, strength, and power. Strength generally remains relatively high
until 50 years of age when decreases of about 10% per year begin to result in a
loss of function and independence; however, little is known about whether
neuromuscular power declines in a similar manner or at the same rate as
strength. The purpose of this study was to document the muscular strength and
power of the upper and lower body and the relationships between the
neuromuscular parameters of strength and power for 3 groups of men representing
the 20–65-year age range.
Healthy, sedentary
subjects were recruited into 3 age groups, 20–25 years (n = 10), 35–40 years (n =
8), and 50–65 years (n = 7).
Following informed consent and medical clearance, measures of maximal strength
(one repetition maximum) and power (piezoresistive accelerometry) were obtained
for the upper (bench press) and lower body (leg press), and fat-free body mass
was assessed by underwater weighing on 2 separate days. Within-day
trial-to-trial reliability was assessed with intraclass correlation
coefficients, whereas day-to-day reliability was assessed with Pearson
correlation coefficients and dependent t-tests.
Group differences were explored with analysis of variance and Tukey’s post hoc
test, and statistical significance was set a priori at a probability level of p = 0.05.
Day-to-day
reliability for each neuromuscular and body composition parameter was excellent
for each age group. The oldest men had significantly more body fat (p < 0.01) but similar amounts of
fat-free tissue when compared with the other groups, yet all measures of
strength and power were significantly lower (p < 0.01) than the 2 younger groups. Additionally, even though strength
and power are theoretically related, the statistical relationships between
these 2 parameters were weakest for the oldest group of men and remained fairly
independent of each other regardless of the age group being examined.
In conclusion, it
appears that the ages of 50–65 years represents a critical period when factors
other than the amount of fat-free tissue are responsible for the beginning
decline in neuromuscular strength and power.
Source: The Journal of Strength & Conditioning Research: Vol. 13, No. 4, pp. 330–338.
MODIFIED WEIGHT LIFTING SAFE FOR OLDER
ADULTS
Many studies have demonstrated that resistance training for senior citizens can be both safe and effective. A recent study has added to this group of research, and found that a properly designed weight-training program for seniors is safe for their hearts, too.
The study published in Medicine and Science in Sports and Exercise, involved 65 healthy adults (32 men and 33 women) ages 65 to 80. Weightlifting exercises consisted of two sets of 12 repetitions at 12-rep maximum (RM) weight, and four sets of five repetitions at 5RM for the leg press, seated chest press and leg extension. Cardiovascular tolerance to the weightlifting exercises was evaluated both physiologically and biologically by measuring heart rate and blood pressure continuously during exercise, and with a blood concentration test both before and after exercise. Comparisons between resting, exercise and postexercise results were then made.
Based
on these results, researchers found that weightlifting exercises, if performed
properly, including using proper respiratory techniques, are safe for older
adults, even those just beginning an exercise program. Of course, such clients
should have a medical evaluation before beginning an exercise program, and they
should be supervised until they and their trainer know they can safely workout
on their own.
Source: Medicine and Science in Sports and Exercise
(Vol.32, No.11)
ENHANCE
PERFORMANCE THROUGH SPECIFICITY
TRAINING
Your best gains in performance will be achieved when
key parts of your training closely mimic what you do when you compete. In other
words, if you specialize in a certain training protocol (specific to your
sport), you will experience a substantial advantage in strength and endurance
during competition.
This is absolutely
true in running. Performing 5-minute
intervals at your 5-K pace will do far more for your 5-K race performances than
will long runs at slower paces, and carrying out 10-minute intervals at your 10-K
race pace will improve your 10Ks more than 25-minute 'tempo runs' at a speed
slower than 10-K velocity. It also
applies to strength training. For example, scientific studies have shown that
when individuals isometrically train their arm muscles at an elbow-joint angle
of 150 degrees, they achieve major gains in strength at that specific elbow
angle but almost no improvements at an angle of 60 degrees, even though exactly
the same arm muscles are involved.
When strength
athletes train with very heavy weights and therefore slow lifting velocities,
they make major gains in their abilities to handle high resistances at slow
speeds, but they're still very poor at lifting more moderate weights at high
velocities. Conversely, when strength athlete’s train with moderate weights and
high velocities, they become very adapt at such activity - but have little
capacity to lift extremely heavy weights at slow speeds.
Expressed yet
another way, the performance of slow, heavily loaded strength training tends to
increase maximal strength but does not improve the rate at which athletes can
apply force (i.e., it helps their strength but not their speed or power). On
the other hand, doing explosive stuff makes athletes great at developing
muscular force quickly, but maximal strength doesn't budge. The latter effect
has been documented in work with plyometrically trained athletes. For example,
athletes who carry out “drop jumps” during training (in a drop jump, an athlete
jumps off a box or step, lands on the ground, and then explodes into the air as
quickly as possible), develop useful upgrades in the rate at which they can
develop force in their leg muscles. But their maximal leg strength may not
increase.
FROM STRENGTH TRAINING TO
RUNNING
Specificity also
applies to the transference of improvements from strength training over to
running. When most runners go to the gym, they focus on the usual, traditional,
tried-and-true exercises that they've read about in magazines, heard about from
other runners, and/or know how to do. These include bench presses, squats,
power cleans, leg extensions, leg flexions, biceps curls, abdominal crunches,
and calf raises. Such exercises are great for developing generalized strength,
but there is one small problem: none of them has anything to do with running.
Basically,
squatting makes you a better squatter. Bench presses improve the strength of
your pectoralis and triceps muscles. Ab crunches help you get better at
bringing your shoulders toward your hips and may make you look prettier at the
beach. Leg extensions increase your quadriceps-muscle strength when you are in
a seated position. None of them helps you run faster in your next 5K.
That's why we
always recommend that runner’s carry out strength routines that are more
specific to the muscular patterns associated with running. Instead of
squatting, ab-crunching, and bicep curling, you should be carrying out
exercises such as one-leg squats, high-bench step-ups, and one-leg hops in
place, all of which closely mimic the overall body posture and muscle mechanics
of running. And once you're good at doing such specific exercises, we recommend
that you move on to strength routines which will help you exert muscular force
in a rapid manner in a horizontal direction, i.e., toward the finish line of
your race. High-speed bounding, running while attired in a weight vest, and
hill repetitions will all help you do that.
Okay, you say, but
where is the proof that such
training is better than the traditional fare of leg extensions and bicep curls?
STRENGTH-TRAINING MODES
COMPARED
Scientists at The
Centre for Exercise Science and Sport Management of Southern Cross University
in Lismore, Australia, divided 30 exercise-science students who had been
engaged in weight training for a period of at least one year (all the subjects
could perform a half-squat exercise with a load greater than body mass) into
two different groups. One group, the control subjects, simply continued their
normal training over an eight-week period. The second group also trained normally
but added in two additional strength sessions per week, each consisting of four
to six sets of six to 10 maximal-effort reps, with three-minute rests between
sets. Only two exercises were used in the training - the squat and the bench
press (each was completed for four to six sets per workout). Resistance was
such that a subject could perform at least six, but no more than 10 reps
(resistance was gradually increased over the eight-week period as the athletes
became stronger).
At the end of eight
weeks, both groups were assessed on a variety of tests of strength and power,
including:
1) A bench-press
throw at a load of 30 per cent of maximum (a bench-press throw is just like a
bench press, except that you try to throw the weight as high as possible; fortunately,
a special electro-magnetic braking system catches the weight before it can
tumble back and strangle you);
2) A counter-movement jump (a vertical jump performed while swinging the arms
back and then forward and up)
3) Maximal squats and bench presses (the two key exercises in the study);
4) A press-up test performed on a force platform to precisely measure force
generated by the shoulders and arms (this was like a normal press-up except
that subjects pushed against the platform with maximal force and attempted to
rocket their upper bodies as quickly away from the ground as possible; their
hands actually left the ground as their torsos moved upward);
5) A maximal 40-metre sprint;
6) A 6-second exercise-cycle test in which subjects tried to exert peak power,
and
7) A series of tests designed to measure shoulder- and leg-muscle strength
carried out on a Cybex machine.
Specificity wins
The results of
these tests strongly supported the specificity-of-training principle. For
example, if we focus only on the leg muscles for a moment, two of the tests -
the maximal squat and the vertical jump - were very similar to the basic
exercise used during training - squatting. The only difference between training
squatting and test (competitive) squatting was that non-maximal loads were used
during training. Similarly, the body posture and muscle-loading patterns of the
vertical jump are very similar to what happens during squatting (both require a
crouching position; both require that powerful forces be exerted in a vertical
direction).
And how much
improvement did the athletes make in maximal squatting and vertical jumping
after eight weeks of squat training? A not-too-shabby 21 per cent! Maximal
squatting capability climbed from 115 to 139 kg, and vertical jumping ability
rose from 20.8 inches to 25.2 inches.
THE UPPER BODY
The story for the
upper body was pretty much the same. The exercise utilized for upper-body
training was the bench press, so it wasn't surprising that maximal bench-press
prowess improved by 12.4 per cent after eight weeks (from 82 to 92 kg).
Likewise, the bench-press throw, which mimics bench pressing exactly except
that the bar is actually thrown vertically into the air, improved by 8.4 per
cent.
However, here's the
really good stuff: the athletes did not improve at all on the maximal press-up
test, even though press-ups involve the same shoulder and arm muscles utilized
during bench pressing. The difference, of course, as we saw in the squatting
case, is not in the muscles actually utilized but in the specific way in which
they are utilized.
The Australian
researchers commented, “'The press-up test involved a similar action to the
bench press and bench-press throw and employed a similar resistance, but it was
performed in an inverted body position such that force was directed downwards,
as opposed to vertically upwards.” In other words, training a particular muscle
to be more powerful won't make that muscle more powerful in competition, unless
the precise movement patterns used in training are very close to those used in
competition.
Finally,
'arm-adduction power' (power exerted as an athlete's straightened arm is
brought toward the middle of the body against resistance) was also unimproved
after eight weeks, even though the key muscles involved in arm adduction - the
pectoralis muscles - are the same ones that are the prime shakers and movers in
bench pressing. By now, you know that the reason for the failure of bench
pressing to enhance arm adduction is that the former is specific to the latter
only in the muscles used, not in the way they are used.
What should you do?
So what's the
bottom line if you're a runner? You should engage in regular strength training,
because scientific studies confirm that it can lower your risk of injury during
training and also enhance your running potential, making it easier for you to
train with higher quality and run faster races.
However, the
strength exercises that most runners utilize - bench presses, squats, power
cleans, push presses, biceps curls, sit-ups, calf raises, hamstring curls, and
knee extensions - are not specific to the body postures or neuromuscular
patterns employed during running and therefore won't help your running very
much. It's fine to do such exercises for a little while, in order to enhance
your general strength and get used to the idea of strength training. But if you
really want to improve your running, you should really focus on resistance
exercises that are more specific to the act of running - such as one-leg
squats, high-bench step-ups, and one-leg hops in place.
Such exercises are
good because they mimic the body postures required for running, but even they
have some limitations, especially since force application is still in a
vertical plane. Of course, the idea behind strength training for running is
ultimately to improve your power in a horizontal direction (most of us don't
run upward; we run straight ahead - toward the finish line or toward the end of
our workout route).
The more specific
your training, the greater the impact training will have on performance. By
specializing you will develop the skill needed for your sport and will perform
far better than your competitors doing standard training. Specific training will also lead you to some
truly amazing personal bests too!
Source: Author, Owen Anderson, www.pponline.co.uk
LONG-TERM EFFECTS OF CREATINE MONOHYDRATE ON STRENGTH AND POWER
The use of creatine
monohydrate supplementation by athletes to increase strength and lean body mass
has substantial scientific support. There has also been great interest in the
use of lower doses of creatine monohydrate for extended periods during heavy
resistance training. The purpose of this investigation was to document the
long-term effects of creatine monohydrate supplementation on resistance-trained
athletes. Sixteen collegiate football players were randomly separated into
creatine monohydrate and placebo groups.
Supplementation in
capsule form consisted of 5 grams per day of creatine monohydrate or placebo
(no loading phase) throughout a 10-week supervised resistance training program.
Pretesting and post-testing consisted of the following: weight; body fat
estimation; 1 repetition maximum bench press, squat, and power clean; and Cybex
testing. Results revealed the creatine monohydrate group was able to
significantly increase measures of strength and power and increase body mass
without a change in percent body fat, whereas the placebo group showed no
significant changes.
The results
indicate that 10 weeks of creatine monohydrate supplementation while
participating in a resistance training program significantly increases strength
and power indices compared with placebo supplementation. These data also
indicate that lower doses of creatine monohydrate may be ingested (5 grams per
day), without a short-term, large-dose loading phase (20 grams/per day), for an
extended period to achieve significant performance enhancement.
Source: The Journal of Strength & Conditioning Research: Vol. 13, No. 3, pp. 187–192.
IS INTENSE EXERCISE HARD ON
THE IMMUNE SYSTEM?
Does exercise, help,
hurt or have no effect on the immune system? Experts have debated that question
over the last few years with no firm answers.
Many fitness experts maintain that regular training improves resistance
to infections and prevents tumor growth, yet athletes and coaches often report
that strenuous training actually seems to produce a higher risk of respiratory
infections. Published studies have shown that marathon runners have a much
higher than normal chance of developing a cold during the week after a
marathon, suggesting that vigorous exercise may open the door for opportunistic
pathogens.
The final word on the link between exercise and health is not in yet, but
there's now evidence that exercise intensity may be a key factor. Specifically,
new research from Denmark suggests that light to moderate exercise boosts
immune-system activity, while intense exercise may depress it.
In the Danish research, six healthy individuals exercised on a bicycle for one
hour on three different occasions, separated by two-week intervals. In one
instance, the subjects cycled at a low intensity of only 25% V02max (just 45-50
per cent of maximal heart rate). On the other occasions they pedaled at either
a moderate intensity of 50% V02max (65 per cent of maximal heart rate) or a
relatively high intensity of 75% V02max (84 per cent of max heart rate). After
each ride, immune-system status was evaluated.
The most dramatic changes in immune-system activity occurred after the
high-intensity ride. Blood concentrations of monocytes - a type of white blood
cell - were above normal, but the activities of two key types of white cells
which destroy invading pathogens - natural killer (NK) cells and Iymphokine-activated
killer (LAK) cells - were suppressed following the high-intensity exertions.
The Danish researchers suggested that the surplus monocytes which appeared
during and after the high-intensity ride released chemicals called
prostaglandin’s which inhibited NK- and LAK-cell activity. That's an
undesirable response, since immune-system strength declines as NK and LAK
activity ebbs.
Meanwhile, concentrations of white blood cells increased during both light and
moderate exercise, as did NK cell activity, and there was no suppression of NK
cells. The Danish researchers concluded that light and moderate exercise tends
to boost the immune system, while intense exercise has some potentially
negative effects.
The Danish cyclists were previously untrained, but the strong observed link
between hard training or racing and illness suggests that the relationship
holds for more experienced athletes, too. It's apparent that sports-active
people should consider cutting back on their high intensity training at times when
the risk of infection is high (for example, in the winter, when athletes tend
to be cooped up with lots of coughing, sniffing people). In addition, when
athletes are under increased physical or emotional stress or are getting less
rest and sleep than usual, it makes sense for them to temporarily bias their
training towards moderate- or low-intensity efforts in order to lower the risk
of illness.
Source: www.pponline.co.uk
GOAL-SETTING
ALONE IMPROVES PERFORMANCE
A group of 51were grouped to perform a novel task under one of three conditions: public goal-setting, private goal-setting, no goal-setting.
The goals selected, time spent practicing, strategies used during practice, and actual performances were assessed.
Both goal-setting groups performed better than the no-goal control group. The public goal-setting group spent more time practicing, but did not eventually perform any better than the less-practiced private goal-setting group. Baseline (initial) performance levels and the goal set predicted performance best. Practice time, training strategy, and public goal-setting did not account for further performance variance.
These results suggest that goal-setting is beneficial for performing a novel task. However, additional practice did not influence performance. This could be an artifact of the task, the type of subjects, and the fact that the task was novel. Since no attempt was made to evaluate learning rates, the reason for the unexpected lack of influence of extra practice was not forthcoming.
Implication. Setting goals, even when learning novel tasks, produces performance improvements over no goal-setting.
Source: Journal of Sport and Exercise Psychology,
14, 169-176. Smith, M., & Lee, C. (1992)
_______________________________________________________
Rob
Wilkins is a Technical Sergeant in the US Air Force stationed at AFTAC, Patrick
Air Force Base, Cocoa Beach, Florida.
Wilkins is also a Special Assistant to the International Federation of
Bodybuilders (IFBB) and a recipient of the IFBB Gold Medal (Oct ’00). To contact Wilkins e-mail him at waaszup@yahoo.com.