MD Training Bytes
By
Steve Blechman and Thomas Fahey
Static but not dynamic stretching decreases strength
Until recently, most people stretched before they exercised. Stretching was
thought to increase joint range of motion, prevent injury, and increase
performance. Many recent studies showed that stretching does just the opposite.
It decreases strength and power output and might increase the risk of injury.
Scientists speculate that stretching interferes with nervous control of
movement. Is all pre-exercise stretching bad? A study from the University of
Oklahoma by Trent Herda and co-workers found that static stretching decreased
muscle strength and activation capacity but dynamic stretching didn’t. Dynamic
stretching involves actively going through a range of motion, while static
stretching involves holding a stretch for 30 seconds at a time. More research is
needed on the optimum warm-up procedure and the risks and benefits of
stretching. Actively working muscles and joints through their normal ranges of
motion before exercise does not impair strength and might actually activate
muscles for better performance during competition or intense exercise. (Journal
Strength Conditioning Research, in press; published online May 2008)
Fast curl-ups recruit the most muscle fibers
Most bodybuilders believe that slow, controlled contractions during weight
training activate the muscle fibers best. Spanish researchers found the
opposite—at least for curl-ups. They measured abdominal muscle activation levels
during fast and slow curl-ups by electromyography (EMG).
They attached electrodes to the rectus abdominis (six-pack muscle), internal
and external obliques (side abs), and the erector spinae (spinal) muscles. They
measured muscle activity while the subjects did curl-ups at four different
speeds ranging from one rep per four seconds to maximum speed curl-ups.
Activation levels increased in each muscle as speed increased. They concluded
that doing curl-ups at fast speeds was best for overloading the abdominal
muscles and building dynamic spinal stability. Don’t do abdominal exercises so
fast that you can’t maintain good technique. (Journal Strength Conditioning
Research, in press; published online May 2008)
Bar diameter does not affect performance during an isometric bench press
Many athletes and coaches think that large diameter bars increase muscle
stress and fiber activation during exercises such as the bench press. Also, some
coaches recommend training with different bar widths to vary the stress of
exercise and increase grip strength. Douglas Fioranelli and Matthew Lee from San
Francisco State University concluded that bar diameter did not affect
performance during an isometric bench press.
They measured isometric force output at two joint angles (chest and halfway
to lockout) using a thick bar (51 millimeters) and a standard Olympic bar (thin
bar at 28 millimeters). The standard, thin, Olympic bar caused the greatest
muscle activation at halfway lockout.
Isometric exercise might not be the best way to measure the effects of bar
width on performance. They might have found different results if they had used a
dynamic exercise. This was an interesting study, but we need more research to
help assess the effects of bar width on strength, training load, and muscle
activation. (Journal Strength Conditioning Research, in press; published
online May 2008)
Dehydration decreases upper and lower body power
Dehydration decreases performance during endurance exercise in the heat and
is the kiss of death in events such as the marathon and triathlon. Athletes in
high power sports such as soccer, volleyball, and tennis often get dehydrated
while playing in the heat. Yet we don’t know much about the effects of hydration
levels on performance in these sports.
A study led by Leon Jones from Chicago State University showed that
dehydration decreased upper body power by seven percent and lower body power by
nineteen percent, as measured by upper and lower body Wingate tests (all-out,
30-second test on a stationary bike or arm ergometer). The subjects were
dehydrated through treadmill exercise and rested 1.5 hours before taking the
power tests. The subjects said their fatigue levels were seventy percent greater
than when they took the tests while normally hydrated, even though they said
they were equally motivated. The authors concluded that dehydration impairs
performance and might increase the risk of injury in athletes playing high power
sports. (Journal Strength Conditioning Research 22:455–63, 2008)
Protein after intense training promotes recovery
Champion bodybuilders or power athletes have the capacity to train hard,
recover quickly, and train hard again. Intense eccentric exercise (negatives or
lengthening contractions) causes muscle damage, post-exercise soreness, and
delayed recovery. Remedies such as massage, heat, cold, and non-steroidal,
anti-inflammatory drugs (e.g. Advil) don’t speed recovery or restore normal
strength and power more than rest alone.
British researchers found that men who took 100 grams of protein (containing
40 grams of essential amino acids) after an exercise designed to cause muscle
soreness and damage (30 minutes of downhill running) showed higher strength
levels 24 and 48 hours after exercise compared to a control group. Strength
decreased by eight percent in the control group (fake protein) 24 hours after
exercise and decreased ten percent at 48 hours. Strength remained at
pre-exercise levels in the protein group during the entire recovery period.
This study showed that taking a supplement containing a large amount of
protein (100 grams) promoted recovery and would presumably allow more intense
training. It isn’t known whether this technique would continue to work during
repeated exercise sessions. (Applied Physiology Nutrition Metabolism
33:483–88, 2008)
Strength and endurance training have different effects on the heart
Weight training and aerobic exercise place different stresses on the heart.
Weight training causes a pressure load, which means that the heart must pump
harder against pressure to overcome the resistance provided by intense muscle
contractions. Aerobics cause a volume load on the heart. Rhythmical exercise
such as running increases the amount of blood returning to the heart, which
stretches heart walls and expands their volume.
A study from the Massachusetts General Hospital in Boston of endurance and
power athletes found that the heart responds differently to pressure and volume
loads. Systolic blood pressure (higher blood pressure number) can exceed 400
millimeters of mercury (mmHg) during heavy squats (120 mmHg is normal resting
systolic blood pressure), which overload and hypertrophy the walls of the left
ventricle that pumps blood into the general circulation. Aerobics cause
increases in the chamber size of the right and left ventricles of the heart (the
right ventricle pumps blood to the lungs). The study showed that training rather
than genetics accounted for most of the heart changes seen in well-trained
athletes. Other studies found that heart changes from intense training reverse
when the athletes stop training. (Journal Applied Physiology 104:1121–28,
2008)
Don’t be a bench press cripple
How much do you bench? Every guy in America with any athletic talent asks
this question when trying to compare his strength with other men. The bench
press is the most popular exercise in the gym and is a general measure of
strength. Most strong guys can tell you when they achieved landmark bench
presses of 205, 225, 300, 315, 350, and 400 lbs. He who lives by the bench dies
by the bench.
Almost all old bench pressers have bad shoulders—usually because of the
technique they used to push the big iron. Many athletes prefer using a wide grip
when they bench, because they don’t have to push the bar as far. This could be a
mistake. Using a wide grip that places the hands greater than 1.5 times the
acromial width (measured at the bony endpoints of the shoulders) causes
excessive abduction (elbows out) of the shoulders during the exercise. This
places high levels of torque on the shoulder joint, which can cause arthritis,
shoulder cartilage injury, rotator cuff tears, and pectoralis major rupture.
Athletes can decrease range of motion during a bench press by using a better
“bench press stance.” Get under yourself when you bench. Bring your shoulder
blades together and brace (tighten) your thigh, butt, and core muscles. This
will stick your chest out and give you a powerful platform from which to bench
press. It will also save your shoulders. Good technique doesn’t hurt. Perform
this exercise correctly and you can bench big weights without becoming a bench
press cripple when you hit 30 years of age. (Strength Conditioning Journal
29:10–14, 2007)
Elite Fitness Systems strives to be a recognized leader in the strength
training industry by providing the highest quality strength training products
and services while providing the highest level of customer service in the
industry. For the best training equipment, information, and accessories, visit
us at www.EliteFTS.com.
