Dirk stormed down the streets toward Tom’s house. The encounter with the bureaucrats had put Dirk in a foul mood, that increased, instead of decreased, with each step away from the lame City Hall. His dissatisfaction with his life rose up like a wave of sand from one of the all too fre-quent Martian storms.
“I’ve only been here a month, I hate wearing the com-pression/sweat recycling suit every time I go outside, I hate walking to the Crane Farm, and I hate being forced to do a job, a job just as easily done by a robot, as is proven by the fact that my only coworker is a robot! I could be back on Earth with my own apartment, own car, making boatloads of money competing in the Games!” Dirk thought to him-self, in what was becoming his customary self-pitying rant/daily negative affirmation.
He knocked on Tom’s door. Tom was the City engineer, responsible not only for the Power Plant, his main area of focus, but the water system and, it seemed to Dirk, every-thing else mechanical.
After a moment, Tom opened the door, his son Tom Junior, who Dirk had nicknamed T2, in his arms.
“Hi, Tom,” Dirk said.
“Hi, Dirk, Hi, Radius” Tom said. “T2, say ‘Hi,’” he said to his son, and moved T2’s arm for him in a wave at both Dirk and Radius. Dirk waved back and smiled in spite of his terrible mood.
“We were heading over to the CentripGym,” Tom said. “It is an improved version of the Omni Directional Fitness system on the ships. You guys want to come along?”
“Sure,” Dirk said, happy for the distraction.
“No, thank you,” said Radius. “I have maintenance to accomplish.”
“Back in a while,” yelled Tom to his wife and making sure T2’s suit was adjusted properly closed the door behind him and started down the street.
“Don’t you guys have your own centrifuge?” Dirk asked.
“Yes, but I like taking T2 to the big one at least every couple of days. He can crawl around on ours, but I want him to experience the bigger space so he doesn’t get used to the small scale of ours and become uncomfortable with the larger ones.”
It took less than five minutes to get to the CentripGym. It was on the east side of the city, close to the Power Plant. The single biggest power consumer, other than the water system and the greenhouses, it was divided from the rest of the City by a small hill made from soil excavated during the installation of the City water system.
“Why did they build this berm between the CentripGym and the rest of the City? Is it so people get a little warm up as they approach the gym to work out?” Dirk asked Tom.
Tom laughed. “No, but that is a good guess. Back on Earth, I remember seeing people riding the escalator from the free weights floor to the exercise machine section. On Mars, if something gets built, it is for one of three reasons. One, it is a absolutely essential for human life, or two con-stitutes a preparatory system for enabling human life.”
“Yeah, like the Oxygen/Nitrogen producers or the Crane Farm,” Dirk said.
“Correct,” responded Tom. “Or three, it is a safety re-quirement. This berm serves the same function as your berms at the Crane Farm. The centrifuge can generate up to 15 earth Gs of force – if it catastrophically failed at that speed, (the cab separated from the drive shaft for example) it would blast like a missile right through the building and go shooting and bouncing along until it dissipated the ac-cumulated potential energy. Being involved in that transla-tion from rotational to linear movement is unpleasant for anything in the way: force = mass times acceleration (F=MA) and you don’t want to be at the receiving end of that force. Hence the berm – it blocks movement toward the City – if the breakage sends the cab or counterweight out into the plain, that is much less a concern from a safety perspective,” Tom concluded.
“– unless you are the guy in it when it breaks” said Dirk.
Tom laughed. “Right, good point.”
Tom opened the door and they walked in. The lights came on automatically, and Dirk was underwhelmed. “It is a scaled up version of the home ones,” he said to Tom.
“Yeah, but this one you don’t have to pedal.” Tom con-tinued, “As you know, the home CentripGyms consisted of one or two (depending on the number of people living there) arms on which a recumbent bike seat and pedal as-sembly are mounted. The people are back-to-back and ro-tate around the center point. Depending on the speed at which they pedal (or alternatively it is possible to disengage the assembly linking the pedals to the drive shaft and allow an electric motor to do the work) the arms spin, applying centripetal force to the people on the arms. The spinning, like in a dryer, rapidly generates a large force the body ex-periences analogously as gravity. The first centrifuges were used for fighter pilot and astronaut training, and later adapted for use on space stations and long voyages to help retain muscle mass and skeletal functionality. But take a look at this – this, this, is what makes our CentripGym the best in the solar system.”
He walked along the raised pathway, past a guardrail demarcating the CentripGym spin area to the wall opposite the door. Behind the CentripGym cab hung a set of shiny Olympic lifting bars and bumper plates.
“Whoa!” Dirk shouted. “This is fantastic!”
Tom smiled. “Yes, its great and practically no one else uses the stuff - no wait for equipment.”
“It is even better than the Omni Directional set up on the ship I used on the trip to Mars,” Dirk said.
The trip over had taken about 11 months. Hibernational technology had to compensate for the lack of propulsion system advances. Most people stayed in hibernation the entire time – after a week of the space cruise they were ready to stay asleep. Dirk’s dad, however, hadn’t wanted him to sleep that long.
“You’re still growing, Dirk, and I don’t think spending nine months racked out is going to be good for you.” Dirk, uncharacteristically, failed to offer any opposition to his dad’s proposal. The idea of losing all his muscle mass was extremely unappealing. Indeed, he almost didn’t come to Mars because of it.
So on the trip over, instead of sleeping the entire time, he read and worked out on the hydraulic Omni-directional fitness system (ODF). The ODF consisted of a series of pis-tons arranged in a sphere with handles at the top of each piston. The pistons extended to provide a full range of motion. For example, securing his feet to two pistons and pulling himself up, enabled him to emulate pull-ups by working against not gravity but the suction provided by the pistons. Presses were easy, requiring pressing against the pistons, like pushing down on a bike pump when filling an almost full tire. With the system he was able to do most of his workout. Once he programmed it for the exercise he wanted to do the computer adjusted the pistons to the prop-er positions relative to his body (length of arms and legs, etc.) so he was able to glide into the center of the machine and get to work.
Sometimes, to emulate the Hero Workouts, he allowed the ODF to select programs for him at random – the 16 display screens would indicate the exercises and the appro-priate handles illuminated to indicate where to the do the press or pull. It was actually really fun, and he’d only wished that there had been someone else there to work out with – competing against the computer was not as much fun.
Some moves, such as the muscle-up, remained difficult to emulate. Even with resistance bands, performing a mus-cle-up in the minimal induced gravity of the transport cruiser was infinitely easier than on Earth, and thus stimu-lated less strength development. Still, what working out he was able to do generated enough of a load on his body that although he knew he wasn’t ready for competition he also hadn’t entirely lost the physical skill and capabilities he’d worked so hard to develop.
“But how do you work out with it here? I mean, you can practically lift the entire set with one hand – the 45 lb. plates only provide 17 pounds of resistance.” Dirk said.
“Right,” agreed Tom. “And that is why we have this!” He flung open the door of the cab to reveal a complicated arrangement of bungee cords and a squat rack and bench bolted to the back wall.
Dirk stared for a moment, taking it in. “When rotating that back wall is the floor, right?” he asked Tom.
Tom smiled and nodded.
“And the bungee cords are used to secure the weights so they don’t fly off independently.”
“Yeah, and pound you to a pulp as they do so,” Tom said.
“That is awesome,” Dirk said. “Let’s work out.”
“Hold T2,” Tom said. After handing the baby to Dirk, Tom grabbed an Olympic bar and climbed into the cab. “First you hook up the bar onto the straps depending on what you are going to do – squats, bench press, thrusters, cleans, whatever.”
“Why the straps? Doesn’t that make it too easy?”
Tom laughed. “Wait until you try it. On Earth you are only working against gravity, which is exerting a pulling force straight down. You move through the range of mo-tion without having to adjust for the direction of the force, or deal with any additional forces, other than the ones you are generating. It is a complicated, but fairly simple process of sequential movement through several planes. In the Cen-tripGym you are dealing with rotational force as well, even though once the assembly is up to speed the force is pre-dominately perpendicular to the axis of movement, or in other words, directly ‘down’ toward the wall. The weights, due to mass variation, are affected differently by the movement. So when during a move in which the bar be-comes “weightless” (as for example during that instant when you transition under the bar during a squat clean) in the centrifuge it is still under the influence of the rotational movement, and wants to move away from you opposite the direction of motion.”
The importance of this dawned on Dirk. “So not only do you have to lift the weight, you have to control it simul-taneously through the rotation.”
“Yes!” said Tom. “Even at very low weights it is an in-credible workout, because you have to control the weight in multiple dimensions simultaneously. The stabilization that your shoulders do during a bench press, for example, is exponentially more difficult here. But of course, difficul-ty is good, because struggle generates muscle growth.”
Dirk was extremely excited – this was much better than the machine dependent resistance training he’d done on the trip out to Mars. Since fitness is in a large part the result of the intensity of the physical challenge and response, not the duration, short periods under multiple g’s (3 or 4) could compensate for spending the remainder of the time weight-less – and life on Mars wasn’t weightless. Now with the large CentripGym he could get back into some real lifting and performing the WODs. “I’ll win the first Martian Games!” he told T2.
“I’ll participate in the Games too, buddy,” Tom said in response.
Dirk thought quickly, “Oh of course, but we’ll be in dif-ferent age groups - I meant I’d win in my age group.”
“Ah, that is what T2 and I thought you meant,” he said with a smile. “Competition is good, and I’m glad you’re here to provide me with a bit of a challenge. You chasing me down will keep me motivated to train. It’s been difficult at times to convince myself to suit up and walk over here.”
“So let’s get to it,” Dirk said happily.
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