Three-year-old Alexander Heyns stands next to his mother at the physiotherapy centre.
He is reaching forward to fit shapes together on the table. "Look, mama, I did it!" he says, eyes sparkling with pride.
His mother, Lynette, says: "When he first came here, he would never do this. He would come in shouting and charge around, touching everything. He found it very difficult to stay in one place, focus and pay attention for any length of time."
Alexander has been having physiotherapy for "low muscle tone' since he was two years old.
While the term "low tone' conjures up the idea of a floppy, weak child, Alexander is big for his age and very active.
Muscle tone enables us to balance our bodies in various positions. Children who lack the muscle tone and strength to keep themselves upright battle with the effect of gravity.
They find it difficult to sit up straight or still. At school, they often get into trouble for not paying attention or trying.
But, in fact, they are trying so hard to keep themselves upright and concentrate on their work that all this conscious effort interferes with their ability to listen to the teacher properly.
Alexander's physiotherapist, Pam Hansford (and one of Babynet's experts), says "low tone" has become a catch-all phrase applied to any children who show signs of not reaching their potential because they have problems of posture and movement.
"Bright kids often mask their difficulties by developing skills in one area - such as climbing or social skills - but they may struggle to stay in one place, or explore with control and confidence.
"The harder these children try to be good at what they are doing, the more tense they get. This distorts their body posture and alignment yet further, and slows them down even more," says Hansford.
Creative problem-solving play
Hansford runs a unique, holistic neurodevelopmental practice for children. The emphasis is on building on a child's strengths, rather than focusing on weaknesses.
Therapy takes the form of creative problem-solving in play - from building houses and playing with shaving cream to running, jumping and surmounting obstacles, learning to handle balls, manipulate "fiddly" toys and draw with confidence.
"Alexander was always very active, and rushed from one thing to the next," says Lynette.
"Because he was our first child, we didn't know any different. And my friends all said boys were all just like that."
But when Alexander went to play-school, his teacher noticed that he didn't like to sit down to paint or play with play dough, he didn't interact much with other kids and that he avoided playing on the jungle gym.
No-one knows what causes it
"The teacher suggested that we take him for an assessment with a physiotherapist, and that is how we ended up here."
No one knows exactly what causes low muscle tone, but traumatic births and a family tendency to low tone are thought to be the main probable causes.
However, Milani Comparetti, an Italian neo-natologist, has pointed out that difficult births may in fact be the result and not the cause of the muscle imbalance if the child has not developed to take part fully in their own birth process.
Sheena Carter of Emory University in the United States says premature babies are "more likely to develop motor problems" than full term babies as they are more likely to suffer problems with their blood or oxygen supply.
Movement deprived
Premature babies' development is also compromised if they have not been exercising in the confined space for the full term.
Instead of being curled up and ready to go as they start to interact with the world, they tend to lie stretched out flat on their backs.
Hansford says many children from more affluent homes are "movement deprived".
Being confined to little plastic seats, stuck in walking rings, sleeping in push chairs or slings as babies and by playing computer games or watching TV for long periods (instead of playing outside) when they are older are all detrimental to the development of good postural balance.
"Safety is important in the car, but once out of the car the less time baby spends lying around in an inclined seat, the better," says Hansford.
"Just look how his back collapses and goes skew. And he isn't in a position to see, connect or use his hands.
"A baby cannot even experience the sensation of your loving touch and does not learn to respond to gentle changes of position and movement.
"Carry your small sleeping baby cradled in both arms. As the baby gets bigger, he should be taught to sit comfortably on your arm, so he can reach forward to touch you and support himself gently, rather than clutching you or sagging back."
Her lament
She says that nappy-changing offers a wonderful opportunity for play and interaction. A tiny pillow or folded nappy under a baby's head will enable baby to see your face and engage in "conversation" as you imitate each other's sound and "talk".
"Babies lying flat on their backs with only their heads slightly raised are also in a position to play with their hands and feet in the air and to practise getting their hands to their knees and feet in preparation for later rolling and crawling functions."
She laments the fact that many parents have dumped the old-fashioned, flat-bottomed carry cots and prams in favour of permanently inclined pushchairs that tend to tip a baby off balance.
She says parents no longer want to let their babies sleep on their stomachs when they can't see them because of fear of cot deaths.
"Let babies sleep on their stomachs during the day, when adults are awake and watching the child. This experience is vital in terms of the movement experience and in terms of lengthening out baby's thoracic spine."
No walking rings
Hansford also encourages parents to put their babies on their tummies to play and to encourage rolling, on the adult's lap or on a big bed at first so that the child can look down as they push up. As soon as the child starts to move, play on a soft surface on the floor.
Walking rings also hamper a child's development by putting "a wide plastic shelf between the child and the world and upsetting a child's balance".
"The child is supported between the legs in a sagging position and does not learn to bear weight through upright hips.
"If children don't learn to use their back and stomach muscles properly, they won't learn how to lean forward and take weight on their arms, crawl and strengthen their shoulders and hips.
"This is important for an upright posture and good pencil control so that a child can function successfully in class."
Problems overcome
For new parents, low muscle tone may seem to be yet another terrifying potential problem lying in wait for their babies.
But Johannesburg physiotherapist Justine Elgar is positive that the combination of knowledge and physiotherapy can help children overcome many postural problems.
The first problem, she says, is that "low muscle tone has become such a buzzword recently, yet few parents and teachers know what it is".
A large part of Elgar's practice involves education. "There is so much pressure on children at school these days, that the average kid just can't cope.
"Many children just need a few sessions of physiotherapy to develop positive habits and restore their self-confidence. Then they're away."
Help childen develop good posture
- Remember to let your baby spend time on her tummy (both when awake and sleeping) and play on her back.
- Encourage cross-legged sitting on the floor on the front half of a flat pillow to encourage an upright back supported by a slight curve in the lower back. Discourage sitting between the legs as the hips turn inwards.
- Make sure the seat and back of the high chair or small chair are at right angles and his feet are flat on the ground, or on a foot rest. Forearms rest lightly on the table. This encourages shoulder control and lifts the ribcage out of the pelvis.
- When your child wants to draw, encourage him to kneel at a low table. Secure the paper with tape. Encourage him to rest his free arm on the table top, not clutching a pen lid.
- Children love discussing the pictures in books and listening to stories. Sit the child on one of your legs with both of her legs over the same side.
- Support the child's arms and the book so that she rests her back upright lightly against your body and the book is in front of the child's face. Her nose should be opposite the middle of the picture being looked at to facilitate the easy flow of eye movement across the midline.
- Create opportunities for crawling on all fours and pushing cars around in the dirt and building block structures.
- Encourage fun and laughter as this reduces tension.