Jump to your heart’s content

It’s before sunrise at Gold’s Gym in Hollywood and there’s an unusual sound coming from the second floor -- a rhythmic tap, tap, tap. Inside a glass-walled workout room, half a dozen people are jumping rope. I am one of them. And let’s just say “tired” has a new name.

Amid the high-tech gadgetry of urban fitness, some people still prefer simplicity. The jump rope, companion to schoolyard youngsters and pro boxers alike, provides one of the best cardiovascular workouts going. It tests the muscles of calves and thighs while toning those of the chest and arms. It burns calories at roughly three times the rate of jogging and isn’t nearly so hard on the joints. It improves coordination and agility, and it’s cheap and portable to boot.

The one thing it’s not, though, is sexy or new -- two strikes against it in L.A.’s exercise culture. But a few clubs, including Gold’s and Crunch, have begun to offer jump rope classes to broaden their selection of cardiovascular workouts.

I used to jump rope often in college and when I lived back East. It was a good substitute workout, especially when the weather was bad. When I moved to sunny Southern California, my jump rope lay idle for years until I grew restless with the day-to-day routine of my cardio machine workout. I decided to give the rope another try.

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Roots in Egypt and China

Apparently jumping rope isn’t just old, it’s ancient. Egyptian and Chinese rope makers stumbled on the activity in the course of their work, according to sports historians. The craftsmen had to twist long strands of hemp into ropes and had to jump over them to retrieve the strands. Dutch settlers brought jumping rope to this country in the 17th century.

Jumping with a group improved my performance. When you’re alone, it’s easy to not push yourself. It’s not like running or jogging, when you’re miles from home and have a powerful incentive to keep going. The Gold’s class was slated for an hour. It started promptly at 6 a.m. Initially, there were five of us, including the instructor, but another person joined later. We started with a five-minute warmup. Nothing fancy; just get those wrists spinning and the toes bouncing.

It could have been the early hour, or more likely the activity. My heart rate soared and I was perspiring heavily. Five minutes is a long time when jumping rope. At this point, I didn’t see how I would get through an entire hour.

After the warmup, we stretched for about 10 minutes, focusing on our calves, hamstrings, quadriceps and lower back. I’m sure this stretching regimen helped mitigate a lot of my post-jump muscle soreness.

Over the next 45 minutes, the class explored the many permutations and styles of jumping rope. Some included jumping while squatting (major thigh burn); hopping up, back and side-to-side; and sliding from one end of the room to the other. In all, we must have hopped, bounced, jumped and danced about a dozen different ways. Needless to say, I couldn’t master them all, and when I couldn’t, I just stuck to the basics -- hopping on two feet or alternating feet back and forth.

Eventually, I got a second wind -- and just in time. We finished up strong with double jumps and sprints. (A double jump is two revolutions in a single jump.) We did three sets of 10 to the four count, executing the double jump on four.

After that, with everyone panting for breath, we paired up to do as many jumps as possible in a minute. Your partner counted; you jumped. I jumped first while my partner counted. I did 157 -- not bad for a beginner, I was told. My partner, a health club Spinning instructor, did just shy of 180.

We finished with another five-minute stretch and some stomach crunches. Finally, we’d completed one of the best all-around workouts I’ve done in years.

As I headed out into the morning sunshine, I dragged myself past people pumping along on rows of exercise machines. I thought to myself: If only they knew the simple joys of a rope.

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(BEGIN TEXT OF INFOBOX)

Snapshot: Jump rope class

Duration of activity: 1 hour, 2 minutes (includes stretching)

Calories burned: 803

Heart rate: Average, 142; high, 181

Target zone: 177 to 153

Time in target zone: 17 minutes

This information was obtained using a heart-rate monitor. Time in the target heart-rate zone is a measure of the intensity of the workout. Target zone varies based on age and individual heart rate.

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Martin Miller can be reached at martin.miller@latimes.com.