How Running Helps Your Muscles, Which Helps Your
RunningBy Trevor Smith -
Contrast the chiseled contours of a successful
bodybuilder with the gaunt frame of an elite marathoner. Then remember both can
achieve stunning results by virtue of their muscles. An amazing feature of your
muscles is how much you can change them by training. When you begin an aerobic
training program, the capillary blood vessels in the muscles you use begin to
increase. You can end up with almost another 50%, added to the capillary
network you had before you began training.
Your muscles need enzymes to tell the power houses
(called mitochondria) in their cells how to carry out the biochemical reactions
that turn carbohydrate and fat into energy. The enzyme activity can more than
double with consistent training.
Part of the fuel your muscles use is right there
in the muscle fibers. This is a complex carbohydrate called glycogen. As you
train, your muscles' capacity for glycogen increases, so you can boost your
stored glycogen by eating more carbohydrates.
If you carbo-load by increasing your carbohydrate
calories to at least 70% of your total calories for at least three days, you
may be able to increase your muscles' glycogen store by more than 50%.
If you practice speedwork, or any high-intensity
efforts that put you into oxygen debt, your muscles produce more lactate as a
byproduct. This causes blood lactate to rise. The increase is gentle at first,
and then rises more sharply. This steeper increase in blood lactate is called
the lactate threshold.
Regular speedwork in your sport will raise your
lactate threshold. This means that your muscles can work harder to produce only
the same amount of lactate. This allows you to run (or ride, or ski, or row
One of the most dramatic changes in sedentary
people as they grow older is their muscles grow smaller, accumulate more fat,
and become weaker. You can avoid the major part of these changes by resistance
training. Build up to eight to 12 repetitions of the heaviest load you can
handle, for each of your major muscle groups.
Two or three sessions a week are enough; you even
gain some benefits by working out only once a week, according to Michael
Pollock, Ph.D., and colleagues at the University of Florida in Gainesville.
Working out against high resistance (or lifting
heavy weights) causes microscopic damage in muscle fibers. During the recovery
period before the next workout, the fibers grow bigger and stronger.
And it's never too late to benefit. Even frail
folks in their 90s increased muscle size by up to 10%, and strength as much as
doubled, according to Maria Fiatarone, M.D., and colleagues at Tufts University
Regular aerobic training and strength workouts,
proper diet and plenty of fluids will keep your athlete's muscles young, no
matter what the calendar says about your age.
The American Running