Most riders have heard of the "bow and string" theory, according to which the horse's abdominal muscles are responsible for lifting the back and carrying the rider. But the theory is controversial and according to veterinarian, author and dressage trainer Gerd Heuschmann, the abdominal muscles are actually for movement - not for carrying weight. In this video, he explains why.

How can working a horse on the forehand cause excessive loading of the hindleg suspensory ligaments? Simple, says German veterinarian, biomechanics expert and author, Dr. Gerd Heuschmann. Sign in now and get his explanation. Duration: 7 minutes.

In Denmark, as everywhere else, the rollkur row is rampant. To clear up a few misunderstandings and explain to ordinary people why low, deep and round - or LDR - is so good for elite level dressage horses, international dressage rider, Olympian and WEG medalist Andreas Helgstrand presented a clinic at the 2010 Danish Warmblood Stallion Licensing, all about LDR. According to Helgstrand and clinic sidekick, bereiter Bjarne Nielsen, it is only possible to train a dressage horse properly by riding it behind the vertical. Anyone who doesn't understand this is clearly ignorant. Here is part one of EPONA.tv's report from the clinic where no questions were allowed.

Many have dabbled in clicker training, managing to perfect a trick or two, but fail to see how the clicker would work from the saddle. Paralympic Bronze medalist Georgia Bruce dispells all doubt that ridden work can be combined with clicker training. She uses the clicker for everything: Training transitions, lateral work and piaffe as well as teaching fun tricks like poster painting and on cue flehmen responses.

On the verge between the trot and walk - when the tempo would naturally warant a walk, but the rider asks the horse to stay in trot, the patient rider may uncover a pleasant surprise. A very elastic, almost cadenced and quite expressive trot, which results from the horse having to keep his balance in the two beat rhythm without using his own velocity as a crutch. Internationally renowned horse trainer and behavioural scientist, Dr. Andrew McLean, explains. Duration: 9 min.

In music, cadence is a pause which gives expression to the melody. In dressage, a gait is said to be cadenced when - with increased collection - the rhythm starts to slow and movements gain in beauty. But there is cadence and then there is "cadence", explains Dr. Gerd Heuschmann. One comes out of flexion of the haunches and the other is but a cheap imitation. Here, he lets you in on the biomechanics behind both.

For building the muscles the of the topline, working on straightness and impulsion, a natural outline is preferred by classical riders to re-educate the older horse who has not been trained right before. Kirsten Hansen explains what long and low is all about and why it may be some time before you can accept a contact.

When the young horse has been prepared on the lunge to work properly through his back, he will usually stay with the rider, once she is on, as it's hard work running away. When possible, dressage trainer Kirsten Hansen avoids using the reins to stop, but for turning, they're indispensable, and technique is everything.

The first time a rider gets on the horse's back, it's likely that the horse will brace his back. To help him loosen up, the rider must make herself as light as possible. Dressage trainer Kirsten Hansen explains the hows and whys of the "remontesitz" or "young horse seat."

To enable the young horse to keep working through his back when mounted as he did during work on the lunge, it's important that the rider acts as passively as possible while the horse is searching for his balance. Watch how things are done when dressage trainer Kirsten Hansen breaks in the chestnut trakehner from the series on lunge work.

The famous German dressage author, Waldemar Seunig, called it "poodle dressage" - the dark art of making a horse so tense it flings its legs about in flashy displays of electric cadence. In this segment, Dr. Gerd Heuschmann explains what exactly makes horses do the "show trot", lifting their front legs up high and leaving the hind end in the barn.

A change of direction is a change of balance, states former ecuyer of the Cadre Noir, Philippe Karl. To teach a horse an aid, first balance him to be placed as well as possible to get the answer right. This means sitting to the left for lateral movement to the left and to the right for lateral movement to the right. Regardless of bend and contrary to what most of us have learned about bending the horse around our inside leg.

What actually goes on in the horse's body as he starts to collect? How do the various muscle groups at work affect his posture? What makes him "sit" and why does he raise his poll? Get the answers here from Dr. Hilary M. Clayton, from the McPhail Equine Performance Center at Michigan State University. Duration: 6 min.

A past competitor himself, Philippe Karl believes that dressage is first and foremost about schooling horses. Not just about showing them. EPONA.tv has met Philippe Karl for an earnest talk about the nature of lightness and the evils of the German half halt. Duration: 11 min.

There are biomechanical reasons for the rule of thumb that the horse's nose should never be behind the vertical. Dr. Gerd Heuschmann explains why the horse needs the use of his neck to enable him to carry the weight of the rider.

The lateral walk is as sign that the horse is tense. Maybe because he is uncomfortable, or because his schooling has been rushed. But exactly how does a stiff back ruin the rhythm of the walk? And what does it look like? Dr. Gerd Heuschmann explains.