Is the summer heat forcing you to retreat into the gym? You may think you can sweat and grunt with impunity as you go about your routine, but there are unwritten rules of gym etiquette. Here are eight commandments that local trainers say every gym user - new or old - must respect.
1. Thou shalt clean up after thyself
Your mother doesn't work at the gym, nor does your helper. After you have used a machine or workbench, wipe it down, and put your equipment away. Even better, use your towel to mop up your sweat.
Gym goers who leave weights on the bar or on the floor are the main peeve of director of Raw Personal Training Studio Jeremy Myer. "If any of my trainers do that, they have to row 500 metres at a pace chosen by me," he says.
2. Thou shalt not treat the changing room as thy bathroom
There's nothing wrong with being comfortable in your own skin, but be aware of your personal practices in the presence of others, particularly in the changing room.
"I once saw a naked lady with her leg on a chair using a towel held at each end to floss her behind," says one local gym goer.
Other don'ts include using hairdryers for hair other than that on your head, staring, uninvited interaction with others, chatting on your mobile, and not putting wet towels in the bins provided.
3. Thou shalt not use thy phone on the gym floor
Let's face it: using your mobile while training is a waste of your time, and everyone else's.
"Trainers are happy when people get off the couch and start moving, but I still get goosebumps when people convert treadmills into furniture," says personal trainer Lory May Martin of PackofPacks.com 
"The upper body is slouched over the handles while the treadmill is set on promenading mode, and they're playing Candy Crush."
It's also the reason you're not seeing any results, adds Myer. "If you're [on your phone] … you might as well stay home."
And reconsider that selfie. "Selfies can be motivation for yourself and others, especially when documenting your fitness progress," says Martin.
"But if it's just to show the world that you're in a gym working those weights … well, you're not really working that hard because you are standing still while trying to find a good angle for your favourite muscle group."
4. Thou shalt not leave thy manners in thy locker
Channelling your inner Arnold Schwarzenegger doesn't mean that you have to stop being considerate. "Don't be rude, manners and humility go a long way," says BikiniFit head trainer Alex de Fina.
"Offer some assistance if you feel that you can be of benefit. Gyms should be a place where the strong push the weak, and the weak challenge the strong."
Another example of bad manners includes dropping weights on the floor, which is noisy and creates a disturbance. Worse still, it can damage the equipment.
"If you have to drop a weight on the ground, it's too heavy," says Myer. Gym users should select the right weight under the guidance of a trainer.
Another practice sure to offend is failing to wear deodorant or fresh clothes. Nobody wants to smell you before they see you.
If you're sick, you should give your gym session a miss, to avoid spreading germs.
"It's simply not pleasant trying to work out next to someone who is sneezing and sniffling all over the equipment. Plenty of workouts can be done at home," says Tricia Yap, also a trainer at BikiniFit.
5. Thou shalt not grunt excessively
You're working hard, but there's no need to start grunting like Maria Sharapova.
Gym bunnies who make too much noise show "a lack of respect for the people around [them]", says Myer. It's also a waste of energy.
"Instead, you should focus on the weight being lifted and the muscle doing the work," he says.
Singing along to your iPod is another thing to avoid. Leave that for the karaoke lounge.
6. Thou shalt dress appropriately
Consider your attire before heading to the gym. Is it too short, tight or revealing? Nobody wants to be distracted during their workout by observing what more closely resembles your birthday suit.
"There is nothing worse than watching someone stretching at the gym and not leaving enough to the imagination," says personal trainer Andrew Wong Kee from JAB MMA Central.
A gym is a place for sports clothing and sports shoes - not for making fashion statements. While your aim may be to impress, your efforts will likely be lost on those around you. "Flip-flops on the treadmill is the funniest thing I've seen," says one local runner.
7. Thou shalt not steal
Gym fees are for usage of the gym and its facilities, not ownership. Would you go into someone else's home and steal items? Don't think so. The same applies in the gym.
Hefty gym fees means users must be affluent but still they swipe towels, shower gel, shampoo and conditioner. These acts of kleptomania add to running costs and increased fees.
While it is permissible to borrow items including towels, particularly to dry off after your workout, don't forget to return them.
8. Thou shalt not be a hog
Hogging gym equipment or dominating workout space is another no-no.
"Sharing is caring," says Wong Kee. "Use the space and or weights and then step aside to let someone jump in while you rest."
Generally accepted use of gym machines during peak periods is 20 minutes. If you need to work out for longer, alternate with other machines, or schedule a longer session during off-peak times.
"Sometimes your programme demands longer sessions or shorter rest periods, so this is a time you may need to be a little selfish. If so, explain to people waiting," says Wong Kee.
Finally, avoid taking up too much space on the gym floor and share space with others. "Bagging" space for future use is a definite taboo, unless it's off peak time says De Fina.
"Using multiple areas is fine; declaring sovereign ownership of shared space is not."
So next time you're working out at the gym, remember: you have been warned.