By Rob Wilkins
The following information IS NOT medical advice and is
solely intended for information purposes. Please consult your healthcare
provider with questions related to the articles below.
OPTIMIZING THE
TIMING OF THE PRE-EXERCISE MEAL
Purpose of study: To compare the effect a 6-hr versus 3-hr
prefeeding regimen on exercise performance. The subjects were 8 active women
(21.4 ± 0.9 years, 60.4 ± 2.4 kg, 19.9 ± 1.3% body fat, and 165.6 ± 2.1 cm). All
women completed 2 exercise trials (separated by 3Ð6 d) on a treadmill where
they ran at moderate intensity for 30 min with 30-s sprints at 5-min intervals,
followed directly by increasing incrementally the grade until volitional
fatigue was achieved. The exercise trials were performed 3 hr and 6 hr after
consuming 40 ± 3 kJ/kg meal. Time to exhaustion was 0.75 min shorter (p =
.0001) for the 6-H trials compared to the 3-H trials.
There
were no significant differences in sub maximal or peak oxygen uptake, heart
rate, or rating of perceived exertion (p > .05). The 6-H trials compared to
the 3-H trials resulted in .05 lower RERs (p = .0002), and a 2 mmol lower blood
lactate at exhaustion (p = .012). Blood glucose levels and cortisol responses
to exercise were similar between trials (p > .05). However, both resting and
post exercise insulin levels were lower during 6-H trials.
Conclusion: Performance of moderate- to high-intensity
exercise lasting 35-40 min is improved by consuming a moderately-high
carbohydrate, low fat, low protein meal 3-hr before exercise compared to a
similar meal consumed 6 hr prior to exercise. Thus, athletes should not skip
meals before competition or training sessions.
Source: International Journal of Sport Nutrition &
Exercise Metabolism, 10 (2).
EFFECTS
RESISTANCE TRAINING ON STRENGTH AND BALANCE IN OLDER WOMEN.
Purpose: This study examined
the effects of resistance training on dynamic and isokinetic muscle strength
and balance in older women with low bone mineral density (BMD). Method:
Twenty-four women (control n = 8, training n = 16) were recruited to
participate in a dynamic resistance-training program. The training program
included eight exercises targeting the lower extremities, at an intensity of
80% of their 1 repetition maximum (1 RM), for 3 sets of 8Ð10 reps, performed
three times per week for 32 weeks. Their 1 RM was measured every 8 weeks for
all exercises and their isokinetic strength and balance at the beginning and
end of the study. Results: No participants dropped out due to injury and only 2
of the training group failed to show good compliance with the training regime.
There was a significant increase (p < .01) in RMs for all exercises (mean
increase 57%) in the training group. The percent increase in RMs was greater
for those individuals with the lowest BMD on those exercises for which they were initially weaker
(leg press, planter flexion, hamstring curl, hip flexion, and dorsiflexion).
However, with minor exceptions, isokinetic strength was unchanged. Associated
with these changes in dynamic strength were significant improvements in
balance.
Conclusion: It
appears that older women with a low bone mineral density can perform chronic
high intensity resistance training and show substantial improvements in
strength and balance, which may ultimately reduce the likelihood of falling.
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Source: Clinical Exercise Physiology, 2 (2).
To answer that
question, a little common sense is in order. The reality is that if you're
ill, you're probably tired, and your muscle strength is below- par. That
being true, you might as well face the fact that your workout is going to be
sub-optimal, so why exercise? Some added rest will actually leave you in
better shape to train intensely in a day or two. From a health
perspective, insisting on working out when you're sick can be downright
dangerous. Instead of having a rhinovirus infection (rhinovinuses are the
ones which produce the common cold), you might actually be infected with
something more lethal, like a virus that can cause pneumonia, or a
'Coxsackie' virus, which can infect your heart and even cause sudden death as
you train. There's no use tempting fate: you'll be able to train strenuously
in a few days, so why risk serious illness now? If you don't buy
these first two arguments for rest, then use what exercise and health experts
call the 'neck check' to determine whether you can train. If all of your
symptoms are above the neck (stuffy or runny nose, sneezing, watery eyes,
and/or scratchy throat), it's okay to start your usual workout at about half
speed. If you feel better after 10 minutes or so, you can increase your
intensity and finish your workout. Otherwise, take some chicken soup, vitamin
C, and fluids to bed with you, and try again in a day or two. However, by all
means do NOT work out if you have a fever or symptoms below the neck (aching
muscles, a hacking cough which seems to resound deep within your chest,
nausea, vomiting, and/or diarrhea). Working out under those conditions is
risky, and you'll recover much faster from your illness if you rest. Source: 'Contagious Infections in Competitive Sports,' Sports Science Exchange, vol. 8 (3), 1995 |
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CREATINE SUPPLEMENTATION IMPROVES INTENSITY
Dietary
supplementation (SUP) has become a significant part of athletic training.
Studies indicate that creatine (Cr) can enhance short-duration, high-intensity
activities. This study examined the effect of 21 days of low dose Cr SUP (~7.7
g/day) and resistance training on force output, power output, duration of mean
peak power output, and total work performed until fatigue. A double-blind
protocol was used, where an individual, who was not part of any other aspect of
the study, randomly assigned subjects to creatine and placebo groups. Forty-one
male university athletes were randomly assigned to either Cr (n = 20) or
placebo (n = 21) SUP. On the first and last day of the study, subjects were
required to perform concentric bench press movements until exhaustion on an
isokinetic dynamometer. The dynamometer was hard-wired to a personal computer,
which provided force, velocity, and duration measures. Force and power output
until fatigue, were used to determine total work, force-time, and power-time
relationships.
Conclusion: Results revealed that the Cr subjects
performed more total work until fatigue, experienced significantly greater
improvements in peak force and peak power, and maintained elevated mean peak
power for a longer period of time. These results indicate that Cr SUP can
significantly improve factors associated with short-duration, high-intensity
activity.
Source: International Journal of Sport Nutrition &
Exercise Metabolism, 10 (3).
EFFECTIVE NUTRITIONAL ERGOGENIC AIDS
Athletes use a variety of
nutritional ergogenic aids to enhance performance. Most nutritional aids can be
categorized as a potential energy source, an anabolic enhancer, a cellular
component, or a recovery aid. Studies have consistently shown that
carbohydrates consumed immediately before or after exercise enhance performance
by increasing glycogen stores and delaying fatigue. Protein and amino acid
supplementation may serve an anabolic role by optimizing body composition
crucial in strength-related sports.
Dietary antioxidants, such as
vitamins C and E and carotenes, may prevent oxidative stress that occurs with
intense exercise. Performance during high-intensity exercise, such as
sprinting, may be improved with short-term creatine loading, and high-effort
exercise lasting 1Ð7 min may be improved through bicarbonate loading
immediately prior to activity. Caffeine dosing before exercise delays fatigue
and may enhance performance of high-intensity exercise.
Source: International Journal of Sport Nutrition & Exercise Metabolism, 9 (2).
EFFECTS OF
EXERCISE ON DIETARY PROTEIN REQUIREMENTS.
This paper reviews the factors
(exercise intensity, carbohydrate availability, exercise type, energy balance,
gender, exercise training, age, and timing of nutrient intake or subsequent
exercise sessions) thought to influence protein need. Although there remains
some debate, recent evidence suggests that dietary protein need increases with
rigorous physical exercise. Those involved in strength training might need to
consume as much as 1.6 to 1.7 g protein á kg-1 á day-1 (approximately twice the
current RDA) while those undergoing endurance training might need about 1.2 to
1.4 g á kg-1 á day-1 (approximately 1.5 times the current RDA). Future
longitudinal studies are needed to confirm these recommendations and assess
whether these protein intakes can enhance exercise performance.
Despite the frequently expressed
concern about adverse effects of high protein intake, there is no evidence that
protein intakes in the range suggested will have adverse effects in healthy
individuals.
Source: International
Journal of Sport Nutrition & Exercise Metabolism, 8 (4).
DO
STEROIDS MAKE A DIFFERENCE?
Although
expectancy has been shown to play a role in the effect of Anabolic Steroids
(AS) on behavior, little research has been completed on the potential for
parallel effects on performance. This is an important area for investigation
because if expectancy effects can be
shown to operate by improvements in performance through the administration of a
placebo, arguments against the use of AS may be more successfully advanced.
Accordingly, the
present investigation used the administration of a placebo (saccharine) with
competitive power lifters, using false information about the nature of the drug
to delineate expectancy effects. The pervasiveness of these effects was further
examined by disclosing the true nature of the drug to half of the participants,
midway through the investigation. Notable improvements in performance
associated with the belief that AS had been administered largely dissipated
when athletes were informed as to the true nature of the drug.
Results indicated
that expectancy played a notable role in performance enhancement. Implications
for this work include more effective use of such investigations in the fight
against doping in sport.
Source: The Sport Psychologist, 14 (3).
THE EFFECTS OF A WEIGHT BELT ON TRUNK AND LEG MUSCLE ACTIVITY AND JOINT KINEMATICS DURING THE SQUAT EXERCISE
Purpose of study: Fourteen
healthy men participated in a study designed to examine the effects of
weight-belt use on trunk- and leg-muscle myoelectric activity (EMG) and joint
kinematics during the squat exercise. Each subject performed the parallel back
squat exercise at a self-selected speed according to his own technique with 90%
of his 1RM both without a weight belt (NWB) and with a weight belt (WB).
Myoelectric activity of the right vastus lateralis, biceps femoris, adductor
magnus, gluteus maximus, and erector spinae was recorded using surface
electrodes. Subjects were videotaped from a sagittal plane view while standing
on a force plate. WB trials were completed significantly faster (p <
0.05) than NWB trials over the entire movement and in both the downward phase
(DP) and upward phase (UP). No significant differences in EMG were detected
between conditions for any of the muscle groups or for any joint angular
kinematic variables during either phase of the lift. The total distance
traveled by the barbell both anteriorly and vertically was significantly
greater (p < 0.01) in the WB condition than the NWB condition.
The velocity of the barbell was significantly greater (p <
0.01) both vertically and horizontally during both the DP and UP in the WB
condition as compared with the NWB condition. These data suggest that the use
of a weight belt during the squat exercise may affect the path of the barbell
and speed of the lift without altering myoelectric activity.
Conclusion: This suggests that
the use of a weight belt may improve a lifter's explosive power by increasing
the speed of the movement without compromising the joint range of motion or
overall lifting technique.
Source: The Journal of Strength and Conditioning Research: Vol. 15, No. 2, pp. 235–240.
NUTRITIONAL IMBALANCE IN ATHLETES
Purpose of study: Examine the influences of nutritional imbalances
on immune function of competitive athletes, who may adopt an unusual diet in an
attempt to enhance performance. A major increase in body fat can have adverse
effects on immune response. In contrast, a negative energy balance and
reduction of body mass are likely to impair immune function in an already thin
athlete. A moderate increase in polyunsaturated fat enhances immune function,
but excessive consumption can be detrimental. Since endurance exercise leads to
protein catabolism, an athlete may need 2.0 g/kg protein rather than the
0.7-1.0 g/kg recommended for a sedentary individual.
Both sustained exercise and
overtraining reduce plasma glutamine levels, which may contribute to suppressed
immune function post exercise. A large intake of carbohydrate counters
glutamine depletion but may also modify immune responses by altering the
secretion of glucose-regulating hormones. Vitamins are important to immune
function because of their antioxidant role. However, the clinical benefits of
vitamin C supplementation are not enhanced by the use of more complex vitamin
mixtures, and excessive vitamin E can have negative effects. Iron, selenium,
zinc, calcium, and magnesium ion all influence immune function. Supplements may
be required after heavy sweating, but an excessive intake of iron facilitates
bacterial growth.
Conclusion: In making dietary recommendations to
athletes, it is important to recognize that immune response can be jeopardized
not only by deficiencies but also by excessive intake of certain nutrients. The
goal should be a well-balanced diet.
Source: Exercise Immunology Review, 4 (1).
EXERCISE ORDER AFFECTS STRENGTH DURING TRAINING
Purpose of study: To measure
the effects of exercise order on performance of isotonic muscle contractions.
Subjects, 17 trained men between the ages of 18 and 29, were strength tested
using 6 standard lifts. Each then completed 2 sessions consisting of 4 sets of
8 reps (to muscle failure), for each exercise with 2 min rest between sets. The
order for one trial was squat, leg extension, leg flexion, bench press,
military press, and triceps pushdown; for the other trial it was leg flexion,
leg extension, squat, triceps pushdown, military press, and bench press.
When the triceps pushdown and military press preceded the bench press,
the bench press total force (TF) was significantly reduced. The TF for squats,
leg extensions, and triceps pushdown were all significantly greater when done
first in the first exercise sequence. Cumulative TF was greater when structural
exercises (multi-jointed) were done first. Fatigue rate and TF for the bench
press were substantially decreased when single-jointed exercises preceded
structural ones.
Conclusion: These results show
that in order to improve strength it’s better to perform the basic exercises
(squats, presses, curls, etc.) first to prevent fatigue.
Source: The Journal of Strength and Conditioning Research: Vol. 10, No. 1, pp. 20–24.
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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.