All equestrian sports reflect a partnership between horse and rider, a partnership built on communication (Fig. 6.1A). Much of this communication is conveyed through the rider’s body position (Fig. 6.2). The higher the team aims to perform, the more subtle these postural clues need to be. Hand position, tension through the reins and bit, shifts in weight along the spine and pelvis, together with a deep seat and relaxed legs, stimulate impulsion and the movement of the horse’s back. Only a relaxed rider sitting correctly can apply aids (the signals by which the rider communicates with the horse) well. An effective but soft seat is dependent on the correct position of the rider’s pelvis and spine.

Fig. 6.1 The horse’s back and neck as an indicator of problems. (A) Correct: The horse moves ‘round’ with the back raised. Proper movement can occur with a round, swinging back and not too much tension in the back, neck and hind legs. (B) Incorrect: The horse moves ‘hollow’ with the back dropped. A tense, hollow back may be caused by problems relating to the horse, the rider or an ill-fitting saddle; it results in a high head and a stiff, uncomfortable gait that prevents the horse engaging the hind legs well, responding correctly to seat aids and ‘working on the bit’. (C) When the horse ‘overbends’, the rider’s trunk tends to tip onto the ‘fork’, the body tilts forwards and the thigh moves too much towards the vertical, the foot tending towards plantarflexion.

(A,B, courtesy of Harris 1996; C, courtesy of Wanless 1995.)

Fig. 6.2 The balance of the rider relative to the alignment of the horse. (A) The pelvis is rolled forwards (anterior rotation: an attempt to balance in the saddle when the horse’s head is held high), causing an increased lumbar lordosis and rounded shoulders. (B) The pelvis is correctly balanced, resulting in the normal slight curves of the spine and a straight, strong back. (C) The pelvis is rolled backwards (posterior rotation), causing a rounded back and shoulders, a collapsed chest and a protruding head.

(Redrawn courtesy of Swift 1985.)

Imbalances on the part of either horse or rider can result in ‘disconnect’ that may adversely affect performance. For instance, if the rider’s posture has become imbalanced or asymmetrical secondary to a vertebral or pelvic malalignment, this information will unwittingly be communicated to the horse. The horse may then respond to commands that the rider is unaware he or she is making. Unexpected or unwanted responses (e.g. failure to turn as easily to one side as the other) frustrate the rider and can be inaccurately attributed to a behavioural, training or limb lameness issue in the horse.

Another example involves the use of aids. The intensity of a rein aid, for example, is made by slight pressure from the ring finger, by a rounding of the wrists or by using the whole arm. The intensity is sustained while increasing forward drive aids to the horse. When the horse submits, the hand relaxes and light control is maintained. An imbalance and asymmetry of the scapulae associated with pelvic malalignment will unwittingly interfere with rein tension (Figs 2.90, 2.120 C).

If the horse is afflicted with malalignment, it may not be able to perform to an expected level. Loss of collection, altered head carriage, refusing jumps or resisting the bit are just a few examples of how the horse’s performance may be affected. Because malalignment often remains undiagnosed, these performance issues are frequently assumed to be behavioural in origin.

Furthermore, because malalignment often results in proprioceptive deficits and reduced muscle mass, if the horse continues to attempt feats it is no longer fit to perform, it is at an increased risk of incurring a secondary injury.

Not only can malalignment issues predispose the horse to further injury, they may also be the result of an underlying subclinical or undiagnosed limb lameness. Frequent recurrence of the same malalignment lesion should raise the suspicion of an underlying lameness.

Proper evaluation of the equestrian team must look at horse and rider, both in and out of the saddle. Consideration must also be given to the saddle itself, to determine how well it fits. An ill-fitting saddle can adversely affect both team members.

To determine the cause of the problem, the conformation of both the horse and the rider must be evaluated, individually and as a working team.

Team evaluations require an assessment of each member individually and with the horse and rider working in tandem. Trainers frequently err by using substitute riders when evaluating the horse, which negates the opportunity to diagnose conditions resulting from the specific pairing of team members.

Another rider, except possibly an instructor who is trained to notice these types of difficulties, may complicate the situation by bringing a new set of skills, and often new problems, to the scene.

Several questions need to be asked to determine whether the horse and rider are suited for each other:

1. Is the horse too big or small?

A basic rule of thumb is that the combined weight of rider and tack should not exceed 20% of the horse’s weight, but such rules are dependent on multiple other factors such as rider experience, saddle size, horse back length, etc.

2. Are their skill levels well suited?

An experienced rider’s vertebrae are mobile but controlled. The spine moves laterally from a convex to a concave position with ease, and the low back moves primarily forward and backward with the sway of the horse (Figs 6.1A, 6.2B, 6.3). The rider can apply a signal to the horse with the action of the spine to urge the horse forward. This mobility and control is not often seen in the novice and the senior rider. A well-trained performance horse may not understand the signals provided by an inexperienced rider’s vertebral movements.

Fig. 6.3 The three main seating positions in riding. (A) Dressage seat. (B) Light seat. (C) Forward (or jumping) seat.

(Redrawn courtesy of Harris 1996.)

If the team is experiencing a performance issue, one first needs to determine where the problem lies. For instance, if the team veers to the left, the assessor needs to decide whether incorrect guidance from the rider is at fault, or if the problem originates from the horse. Perhaps the rider has a malalignment of the pelvis with a ‘right anterior’ innominate rotation. The right ischium will be found to be high (Figs 2.73 C, 3.86B, 6.4A,C); whereas the left ischial tuberosity is lower and puts pressure on the horse’s left paravertebral muscles, causing a reflex increase in tension in these muscles. The rider’s right shoulder and hip are too far ahead of the action, so that the rider appears to be perching on the saddle (Figs 5.37, 6.4Bii, C). The right hip ends up in extension, and the right leg goes too far behind the girth of the saddle. Incorrect signals are communicated to the horse because the sitting position of the rider is incorrect. Conversely, trapezius and paraspinal restrictions of the horse’s mid-thoracic region could shorten the left forelimb stride length, which can also result in the team veering off course. Both conditions could exist concurrently.

In many cases, the rider complains of muscle spasm and in some cases stiffness when mounting and dismounting. Muscle spasm can be evoked in the vicinity of an injury or lesion as a protective reflex to prevent unwanted movement. This protective reflex is also operative if the pain originates from a joint. The muscles are not necessarily in constant spasm around the injured joint, but movement beyond a critical point can trigger specific groups to contract. The observed pattern of spasm can then be interpreted to determine the type of malalignment present in the horse and/or rider. Spasm in the left quadratus lumborum, the left paraspinal muscle at L2 and L3, and/or the left latissimus dorsi can, for example, indicate pelvic malalignment with thoracic and shoulder involvement.

Malalignment in the rider

The balance and seating positions of the rider

Equestrians communicate instructions to their horses through subtle changes in body and limb position. Different sports place different demands on the horse and, therefore, require a different ‘seat’ or riding position. Each seat is intended to guide and provide harmony of movement with the horse. Balance needs to remain centered, yet also needs to flow with the dynamics of the horse. In traditional English riding, there are three main seating positions in equitation (Fig. 6.3):

1. the dressage seat (also called the basic seat)

2. the light seat

3. the forward (or jumping) seat

Following is a description of these seats and how they may be adversely affected by malalignment of the rider.

The dressage seat

The dressage seat is considered to be the basic seat for training a horse and rider in flat work.

To achieve this seat, the rider should assume a normal upper body position, with a vertical spine centered above the sacrum and the pelvis evenly positioned (Fig. 6.3A). By engaging and relaxing the paraspinal muscles, the rider is able to move harmoniously with the horse. The shoulders should be slightly retracted and depressed at the scapulae. Shoulders and heels should be in perfect vertical alignment.

The upper arms should be relaxed and move freely in a flexion–extension motion from the shoulder joint. The elbow is flexed, and the forearm is in a mid-position with the wrists straight, the fingers flexed and the thumbs uppermost. Relaxed shoulders, elbows and wrists ensure that the rider’s body movements are not transmitted through their hands. The head is carried erect, with vision directed toward the intended direction of movement. The chin must stay in line and not push forward.

The ischia and pubic symphysis form the triangle of the seat. The thighs lie flat against the saddle, with sufficient coxo-femoral internal rotation to allow the medial surface of the knee to contact the saddle fully. The line of the rider’s thigh should be as vertical as possible without taking the weight off the ischium (Figs 6.1A, 6.2B, 6.3, 6.4Bi). Having a long line to the thigh ensures a deep knee position which enables the rider to apply the lower leg to the barrel of the horse.

The rider’s legs below the knee usually slope backward and downward. Depending on the length of the leg, the knee joints are typically flexed to 30 degrees. The medial surface of the calf keeps a light contact with the side of the horse.

The toes and forefoot are dorsiflexed and everted, pointing forward and slightly outward. The stirrup is positioned under the metatarsophalangeal joints and the weight of the rider normally transfers backward from the metatarsophalangeal joints to the heel. The ankle needs to flex freely with the horse’s movements.

Should the rider be affected by a malalignment of the foot and ankle resulting in supination of the forefoot, the foot will plantarflex and elevate the heel. Consequently, weight can no longer be distributed backward through to the heel, the upper body is shifted forward and the hands drop. The head moves forward as well, into a ‘poking chin’ posture (see Fig. 6.2C).

Pelvic imbalances such as sacral torsion and/or locking of a sacroiliac joint can prevent the rider from maintaining correct positioning. For example, an ‘anterior’ rotation of the pelvis on one side, in which the innominate ends up rotated forward and upward (Figs 5.37, 6.4, 6.5), causes asymmetry in thigh position. If the rider attempts to compensate, the knee on the side of the ‘anterior’ rotation is forced either externally or internally. The former position leads to an insecure seat (Figs 5.37, 6.4Bii,C); the latter rotates the lower leg away from the horse, reducing the ability of the rider to communicate using the medial calf or heel.

Fig. 6.4 A rider sitting ‘off centre’ (A) The right shoulder and pelvic (iliac) crest are obviously higher than the left, the pelvis being rotated to the left (forwards on the right). (B) The rider’s ‘good’ (i) and ‘bad’ (ii) sides. As the rider collapses (i.e. goes out of alignment, with right anterior rotation), more of the chest shows, and the twist carries through to her thigh, so that it hangs away from the saddle: she clings on with just part of it. (C) The ‘collapse’, seen from the back. The rider’s inside leg-body angle closes, whereas the outer angle opens. (D) The rider…is now sitting squarely in the saddle: the pelvic crests and shoulders are even and the spine straight.

(A,D, courtesy of Swift 1985; B,C, courtesy of Wanless 1995.)

Fig. 6.5 Left anterior rotation can be one cause of an abnormal sitting position or ‘crookedness’. The left ischial tuberosity is raised off the saddle, losing contact and resulting in a shift of position, with the left pelvis and shoulder in forward rotation.

(Courtesy of Hill 1992.)

The light seat

The light seat is useful for flat work with show jumpers and when there are frequent changes between the flat work and jumping.

The light seat reduces the burden of weight on the horse’s back (Fig. 6.3B). The stirrups are shortened two holes to lean the rider forward and increase flexion at the knee. This position releases some of the weight from the ischium and puts more of it through the upper leg. It also engages the hip flexors and adductors.

Pelvic malalignment results in an asymmetry of strength through the hip girdle and leg muscles (see Ch. 3, Appendix 3). This imbalance, in addition to the malpositioning of the legs, contributes to uneven weight distribution in the saddle. For the rider to achieve a true light seat, there can be no malalignment of the pelvis and spine.

The forward (jumping) seat

The purpose of the forward seat is to give freedom to the horse’s back and enable the rider to follow quickly all the balance and movement changes of the horse.

The forward or jumping seat is an advanced position recommended only after acquiring a safe, balanced dressage and light seat (Fig. 6.3C). It is used for both jumping and galloping and the rider must be able to transition easily between this and the light or forward seats between jumps. Failure to execute these transitions in a balanced or symmetrical fashion can throw the horse off stride.

The stirrups are again shortened to promote knee flexion and ankle dorsiflexion, and are placed mid-metatarsal rather than at the metatarsophalangeal joints. Failure to position the stirrup correctly or maintain the forefoot in plantarflexion, rather than dorsiflexion, can result in ankle joint immobilization (see Ch. 3; Fig. 3.30)