It is essential for all ridden horses to maintain suppleness in their back and loins. By contracting the horse’s abdominal muscles, the back will stretch. The abdominal muscles (rectus abdominis, internal and external abdominal oblique) as well as the hip flexors (iliopsoas) are responsible for lumbo-sacral and hip flexion. When these muscles contract, the horse’s bottom line is shortened while the top line is lengthened. The hindquarters become more engaged, the horse becomes more comfortable to ride, and his weight-bearing capacity is improved.
The lumbo-sacral joint is very important, as keeping it supple will help create engagement and develop power, improving the horse’s athletic ability, such as increasing his capacity to lengthen stride. This joint is also important for the maintenance of balance.
Here are the trunk and loin extensor muscles and their functions:
Trunk Extensors
Spinalis thoracis extends the thoracic vertebrae.
Longissimus thoracis extends the vertebral column.
Iliocostalis thoracis extends the vertebral column.
Multifidus thoracis and lumborum twist the vertebral column.
Serratus dorsalis caudalis extends the thoracic vertebrae.
Loin Extensors
Medial gluteus extends and abducts the hip, but with its connection to longissimus lumborum extends the loins.
Accessory gluteus assists the medial gluteus.
Longissimus lumborum extends the lumbar spine as well as the hip through its connection to the medial gluteus.
All these muscles are interconnected from the croup to the poll. Contraction of the abdominal muscles will lead to stretching of the entire group of extensors. During the contraction of the abdominals, the horse’s back becomes rounded, the loin flexes, and the hindquarters are drawn under the body.
3 Active Stretch Exercises for the Trunk and Loin Extensors
In order to stretch the loins actively the iliopsoas (iliacus and psoas major) and the abdominal muscles have to contract.
1 Walk and trot over 6 to 8 ground poles, encouraging the horse to stretch his head and neck down. Keep the first and last poles spaced a little closer than the middle poles. If the distance of the first two poles is too long and you do not bring the horse close enough to the first pole, he will take an extra step in the first or second space. If all the poles are of an equal distance and the distance is too long, he will take an extra step in the last space. By putting extra steps in, he will thus shorten his stride instead of lengthening it.
2 Incorporate backing-up (rein-back) exercises into your riding session. Start with a few steps only, then slowly build up to 6 to 8 steps. Next, back up a slight incline—note that this has a very strong stretching effect on the loin extensors, so start with only one or two steps then increase the amount slowly. Do not repeat this exercise too many times as it may cause muscle strain. Backing up is physically difficult for the horse, since he has to lift his hind legs one at a time without putting his weight on his forehand. This means that the one hind leg has to carry the horse’s weight while the other is moving backward, and vice versa.
3 All transitions strengthen the abdominal muscles and the iliopsoas and therefore stretch the loin muscles. Start with trot-walk-trot transitions and progress to trot-halt-trot transitions. To perform these correctly the horse will have to bring his hindquarters more underneath him. Move on to canter-trot-canter transitions and when the horse can master this with balance and ease, do canter-walk-canter transitions. The latter exercise develops the most power in the bottom line muscles and stretch in the top line.
Find more excellent and easy-to-do stretch exercises to help prepare your horse to perform better, as well as keep him healthy and happy in STRETCH EXERCISES FOR YOUR HORSE, available at the TSB online bookstore, where shipping in the US is FREE.