At the most basic, muscle activation is the process of contracting or shortening a specific muscle, before relaxing it again. Muscles activate according to the timing and strength of neural impulses firing from your brain. However, in the human (and equine!) body, nothing ever acts in isolation.
When a muscle activates, it creates force and movement in muscles far away from the active muscle. Like a set of dominos, contracting one muscle impacts every muscle around it in a chain reaction. For example, a simple everyday motion such as walking involves every muscle from your glutes down to your tibialis posterior, located in the arch of your foot.
With every stride you take, muscles throughout your body contract and relax in a complex symphony of movement that takes the average person an entire year of life to learn.
Neural Impulses and Muscle Activation
The generally accepted dichotomy of turning a muscle “on” or “off” is misleading. Instead of a simple light switch, your body operates more similarly to a dimmer switch. Neural impulses can activate muscles and muscle groups throughout your body at differing strengths. The weakest neural impulse causes a muscle to barely twitch, while a strong impulse activates a muscle at full strength. If muscles were only able to be “turned on” at full strength, we’d move in jerky harsh patterns, like a marionette– not very good for a professional equestrian riding a sensitive animal like the horse.
Neurons can be incited to fire and activate various muscles by mild electric pulses, as well as by the human will (to put it somewhat dramatically). When riding, these neural impulses are responsible for activating both the large muscle groups, such as the pelvic sling in the two-point, as well as the minute muscles needed to half-halt or tilt a seat bone.
Anatomy Slings
Here’s where things get complicated. Anatomy slings are groups made of muscle, fascia, and ligaments all working together to stabilize and move the body. The force of a muscle contraction is distributed throughout the sling, in what is called “force vectors.” If balanced, these vectors align the bones and joints through dynamic movement.
Let’s look at anatomy slings from a different perspective. Imagine you are playing tug of war. The flag is perfectly in the center with a partner who is equally matched in power/strength as you. When you start pulling, the two of you pull at the exact time with the same power so the flag stays in the middle. But, if the two of you are out of sync, meaning that someone pulls first or if your partner overpowers you, they can easily take the advantage to pull the flag to their side.
In this simple visualisation, the rope is an anatomy sling (muscle, fascia, and ligaments) with the timing and power of the pull as the neural impulse. You and your partner are the anatomical structures moving away from each other and causing the force vectors.
Let’s put that in equestrian terms of inside leg and outside rein. The posterior oblique (PO) sling is what keeps your sacroiliac joint and lumbar spine stabilized. The PO sling is made up of the diagonal latissimus dorsi, gluteus maximus, and the thoracolumbar fascia connecting them. In this tug of war match you are the inside leg and your partner is the outside rein. You and your partner have to act with equal power to maintain balance in the saddle. Meaning, if the inside leg muscles are “turned on” more than the muscles that support the outside rein, the rider’s trunk may curve to the outside of the circle to overcome the power of the leg. The opposite may occur too, when the outside trunk and arm muscles are “turned on” more than the inside leg causing the rider’s trunk to curve to the inside of the circle.
An easy way to help train the PO sling is by using an exercise band. You will stand with one end of the band under one leg and the other end in the opposite hand. Now simultaneously pick up the foot without the band and raise the hand holding the band up out to a 45 degree angle. The foot stabilizing the band on the ground should be pushing with the same power down and to a 45 degree angle as the arm. The goal is to activate the diagonal arm and leg muscles in a slow, coordinated pattern with equal power. This can be a strengthening exercise, however in this case it is working on conscious neural patterning to be more body aware. This helps with your riding synchrony and obtaining the inside leg outside rein connection with your horse.
When riding, exceptional equestrians rely on these anatomical slings to allow you to move in perfect harmony with your horse. If the force vectors become out of balance, they can pull your musculoskeletal structure out of alignment and cause you to move in contradiction to your horse’s movement.
How Physical Therapy Helps
A weakness in any of your body’s anatomy slings creates poor performance, a lack of strength, and can even lead to pain or injury. Physical therapy can help you learn how to activate these muscle groups appropriately and in balance. Keep in mind that the longer you wait to start treatment, the more your muscles will have learned to repeat unbalanced movement patterns.
Physical therapy retrains your muscles to fire appropriately. Prescribed exercises create balance in anatomy slings and various muscle groups to allow for increased performance.
Timing is Everything
Our sport is based on appearing as though we “do nothing.” Hence the common complaint that equestrians “just sit there.” This is anything but true. The reality is that activating the right muscles at the right time with the right level of strength is everything in the saddle.
It takes a huge amount of strength, control, and harmony in order to move so smoothly with our equine partners that we appear to do nothing. Appropriate muscle activation is key to succeeding as a professional equestrian. If you feel as though you can’t figure out which muscle to activate or as though you’re stuck in a performance rut, start your physical therapy journey. Reach your goals.