A recent article in the American Journal of Sports Medicine announced that when their muscles are warmed in water, rabbits are less likely to suffer a muscle tear. But you're not a rabbit, and passive warming will not protect you from exercise-related injuries.
It's true, raising muscle temperature can help prevent injuries. When a muscle is cold, it contracts sluggishly and may tear. When it is warm, the muscle is more pliable and less likely to tear. The rabbits studied by researchers at Duke University had their muscles warmed -- up to 101 degrees -- for an extended time. Those muscles, when stretched, could withstand more force before tearing than muscles kept at 95 degrees.
But that doesn't mean you can sit in a sauna and expect to exercise without increasing the chance of getting injured. To warm muscles before exercise, you must significantly increase the blood flow to the muscle fibers. Passive warming -- such as sitting in a hot tub -- will not do that.
Your pre-exercise warm-up also must be specific to your sport. Calisthenics will not warm your muscles for jogging. The best way to warm up before jogging is to run very slowly, gradually increasing your pace. The best way to warm up for bicycling is to pedal slowly. The best way to warm up for swimming is to slowly swim a lap or two.
If you are warming up for competition, you must exercise almost to your pace during competition. Such an approach helps your muscles contract with greater force so you can run faster, jump higher, swim more swiftly, lift more weight and throw much farther.
Q: My health club has several types of rowing machines. What's the best?
A: The best rowing machine has a wheel that spins and a seat that moves back and forth.
Older, conventional rowing machines have oars attached to a resistance mechanism that contains a piston inside a casing (and which looks like a car's shock absorber). When you pull on the oars, the piston moves at a constant rate so strong that you have to pull the oars toward you at a constant speed. This action does not feel comfortable, because your natural tendency is to start out slowly, accelerate as the oars move toward you and decelerate as you pull the oars close to your chest.
Newer rowing machines are made with spinning wheels. You pull on oars that are attached to a rope, which causes the wheel to spin. Since the rate of the spin depends on how hard you pull, you can accelerate and decelerate as you row.
In an informal survey, 95 percent of people who tried both machines preferred the one with the wheel. They said they could exercise longer on that machine.
All good rowing machines also have moving seats. When you sit down to row, bring the seat as far forward as possible. Push your feet against the stirrups so the seat starts to move back. Once the seat begins to move, start to bend your body backward. Finish by pulling the oars close to your body.
Dr. Mirkin is a practicing physician in Silver Spring specializing in sports medicine and nutrition.