Engagement and Collection:
How are they Related?
In our last column, we discussed the initiation of forward movement. We covered the biomechanical process and the importance of freedom of movement of the spine in order to achieve true engagement and the use of chiropractic to help insure the horse's ability to achieve engagement. To build upon this topic, we will now discuss collection and how it relates to engagement.
Simply put, collection is the bringing together of both ends of the horse for the purpose of lifting and lightening the forehand. To achieve true collection, the horse must have proper engagement. With proper engagement, the power of the stride is generated from the hind limbs coming coming up underneath the horse, flexion of the pelvis and lumbo-sacral spine and then a transfer of this energy forward through the spine. With true collection, the head will telescope forward and the neck will rise in an arch, and this will allow the poll to flex naturally, allowing the face to become vertical and perpendicular to the ground. With true collection, this head position is achieved naturally, it is not forced.
The horse can use head position to shift the center of gravity and to initiate movement, but this is not true engagement or collection. The head is very effective in shifting the center of gravity forward because it is relatively heavy and is attached to the end of a long lever. The horse can achieve this change in the center of gravity through a change in head carriage such as tossing the head during transitions or carrying the head up and back. Behaviors such as this are abnormal and are frequently an avoidance mechanism by the horse or an attempt to compensate for a restriction in mobility in some portion of the vertebral column. In many cases, the problem is exacerbated by the use of training aids that are designed to force the head down and into a flexed position. This can lead to an over flexing at the poll with the horse going "behind the bit". This moves the center of gravity further forward, attempting to use momentum (and not engagement) to create forward movement and the horse ends up further on the front end. The result is a biomechanically abnormal gait that prevents the horse from achieving engagement from the hindquarters. This aberration in biomechanics in turn can cause other problems for the horse.
Thus, it is evident that the horse can only achieve true collection if he is truly engaged from the hindquarters. The horse can only be properly engaged if there is a normally functioning nervous system that provides the proper stimulus to the musculature to fire as needed to contract the abdomen and flex the pelvis and lumbar spine. The vertebral column must be moving appropriately in order for the nervous system to function properly, and chiropractic evaluation and adjustment is the most specific treatment modality to insure the proper movement of the vertebral column. Chiropractic care is vital to maintain the health of the nervous system and may be a critical component of one's quest to achieve engagement and true collection.