Which Comes First, Cardio or Weights_ - Alex Hutchinson [37]
To pump your arms, you need to activate your arm and shoulder muscles. But a 2009 paper in the Journal of Experimental Biology challenged the idea that muscles play any role in normal arm swing during walking or running. They performed a series of experiments suggesting that arm swing is passive rather than active, occurring naturally to counterbalance the rotation of your lower body. In other words, if you had rubber arms with no muscles in them, the twisting motion of your lower body would cause the arms to swing exactly the way they do in real life (other than minor details like keeping your elbow bent while running).
Support for this notion is found in a 1998 paper from Yugoslavia, in which researchers carefully measured the effects of attaching small weights to the arms and legs of sprinters. As you’d expect, even small loads of about a pound on the legs dramatically slowed sprint speed—but loads of up to 1.5 pounds on the arms produced no effect whatsoever. If arm motion was really helping to drive leg speed, you’d expect the arm weights to have an effect. The logical conclusion is that you should focus on keeping your arms relaxed so they can swing freely, rather than trying to force them to pump faster. To achieve this, coaches often recommend keeping your shoulders low and your hands unclenched.
But not everyone agrees that the arms are strictly ballast. Researchers at the University of Michigan studied patients rehabilitating from spinal cord injuries and reported an interesting observation in 2006: rhythmic arm movement seemed to help the patients as they tried to regain movement in their legs. They saw this as evidence that arm and leg movement originate in the same part of the brain, suggesting that “arm swing may also facilitate lower limb muscle activation via neural coupling.” Other researchers had similarly argued that, as a legacy from our long-distant past as quadrupeds, the motion of all four of our limbs is still coordinated. To test this idea, the Michigan researchers strapped healthy volunteers into a “recumbent stepper”—basically an exercise machine that requires you to move either your arms, your legs, or both. Sure enough, they found that when subjects moved their arms back and forth, their brains were able to recruit more muscle fibers to contract in their legs than when they didn’t pump their arms.
This research is still too preliminary to draw any firm conclusions. It doesn’t contradict the finding that our arms swing primarily to balance the motion of our legs. But it does suggest that, when you’re fatiguing at the end of a hard run and your legs are starting to fail, keeping a nice, steady rhythm with your arms just might help you keep going.
Do spinning classes offer any benefits that I can’t get from biking on my own?
In theory, cycling is cycling. The pulse of the music, the exhortations of your instructor, and the presence of a group of like-minded exercisers do nothing to spin your pedals. In practice, though, the ingredients of a typical indoor cycling class somehow combine to lift workouts to heights that most participants wouldn’t achieve on their own. The alchemy of group exercise is well known to runners and aerobics classes (see Chapter 11), but spinning has found a recipe so powerful that researchers studying it have been forced to re-evaluate their definition of “maximal” exercise—and sound a warning for beginners who may wander into a class unprepared.
The current incarnation of group indoor cycling dates back to 1987, when South African–born cyclist Jonathan Goldberg first organized training sessions in the style he later trademarked as “Spinning.” These days, more than half of North American health clubs offer group cycling classes, reaching millions of participants, according to figures from