At a martial arts and fitness studio in Central, two men hammer each other at a jiu-jitsu session. In another corner, a trainer shows his class how to duck walk. This, trainers say, is the kind of place we should all be heading to at lunchtime if we are to enjoy good posture, strong back, neck and stomach muscles and avoid pain. 'Lately, we have been getting an influx of corporate clients whose jobs require them to be desk-bound all day,' says Andrew Wong Kee, owner of JAB fitness studio. 'Sitting down hunched over a computer for up to 12 hours a day can cause major postural problems.' Simply put, we sit for too long in poor positions, setting ourselves up for a myriad of joint and muscle issues. 'People sit at their desks working and they become too cerebral ... they forget about their bodies,' says Dr Damien Mouellic, an osteopath at Lauren Bramley and Partners. Of course, people have been sitting at desks for many years. However, the extent of the problem may be only just rearing its head alongside the increasing demands of modern life's workload. For example, if you started at a desk 20 years ago - before the internet/PC explosion meant more sitting - your body may be just showing the signs. Or, they were there and have, over time, become too bad to ignore. Starry Wong, a massage therapist at Sutherland-Chan Centre, says one-third of its clients come in to treat a bad back, but half never noticed it was tight as they were not in pain. 'But a few treatments later, they begin to realise how tight their backs were.' Andrew Wong says: 'People ... tend to have muscle imbalances right the way through the body that can stem from simple things like tilting the head to one side all day while talking on the phone. Unfortunately, although these problems can seem simple to begin with, if left unchecked, they can cause huge issues later on.' Aaron Mattes, founder of Active Isolated Stretching, is familiar with the negative affects of a sedentary lifestyle. The American-based kinesiologist was in town recently to keep an eye on trainers here who use his stretch programme to help people with physical imbalances, pain or tightness. 'The computer has been one of the greatest gifts to the therapeutic business,' jokes Mattes, 68. 'People sit down for eight to 10 hours a day, even more, and as you do this, hip flexes get tight and short, as do your hamstrings. Your buttocks get atrophied. Stomach muscles get weak and our posture becomes compressed. 'You get that turkey-neck posture from weak neck muscles, and our anti-gravity muscles are not holding us the way they should. It's probably one of the most common problems that we see.' He cites the case of a businessman who visited the Hong Kong clinic recently with numb fingers 'coming from irritation in the neck'. His posture was so bad it had put pressure on the neck, Mattes says, who also claims to have fixed the problem in one day by correcting the man's upper body rotational muscles. Andrew Wong says he also sees a lot of desk-associated physical problems. Tight hamstrings and hips can cause lower back pain, he says, while tight iliotibial bands (a group of fibres running along the outside of the thigh) cause an increase in knee-related injuries and pain, and imbalances and weakness in the head, neck and shoulders. 'This can lead to headaches, fatigue and a host of other symptoms that may seem unrelated at the time,' he says. But there are simple solutions. Aside from exercising in your spare time, Wong says that one of the best things is to get up and stretch at regular intervals, perhaps setting a screen saver as an alarm. 'You could also try to convince your boss to make your work station more ergonomic. Basic things like switching your seat for a Swiss ball will make you more aware of your posture. They encourage you to sit up straighter and use your abdominals so that you can actually balance. 'Tennis balls and foam rollers are also simple yet effective tools for releasing muscular tension.' Getting away from your desk every hour and walking around, or just standing more often (as much as every 10 minutes), for example, while on the phone, can also help. 'If you've been sitting in a car for an hour or so, you know that when you get out, you need to stretch your legs,' says Mattes. 'So if you're sitting at a desk for two hours, you need to be doing the same thing.' Starry Wong says her tips are to stretch both arms outwards and upwards to elongate the pectoralis muscles. Then gently lean backwards. Or, shrug shoulders and relax, arms crossed - the left hand grasping the right shoulder blade and right hand grabbing the left blade - to stretch the upper back. 'Stretch back muscles by sitting in your chair at the office and bending forwards so your hands touch the floor. Relax, and let your body hang. Take a deep breath in, then when breathing out, stretch further towards the floor,' she says. Rotate and stretch back muscles by sitting in your chair, back straight, and rotate as far as you can to one side, grabbing the back of the chair and holding for 20 seconds. 'Then rotate to the other side and grab the other side of the chair and hold for 20 seconds.' She also says to avoid crossing your legs too often. 'This causes hip rotation, which in turn, twists your lower back.' For Mouellic, a lumbar support is essential when sitting. 'It prevents slouching, which causes restricted breathing, digestion difficulties, tight anterior neck muscles and reduces core strength,' he says. Of course, regular exercise outside the office is also important. And while it might not be for everyone, Wong says, martial arts can help balance a sedentary work life. Kick-boxing, ginastica natural (a Brazilian form of mat exercise) and Brazilian jiu-jitsu use rotational movement through the spine and mobility through the hips, hamstrings and shoulders. Andrew Wong says: 'Even though it may seem challenging at first, just working through simple drills is beneficial for increasing muscle and joint range of movement. Repetition and consistency is definitely the key.'