April is “Adopt a Greyhound” month (see http://www.adoptagreyhound.com.au/). Greyhounds are well known as being loving, gentle dogs that are well suited to many households. Their unique muscle structure, particularly in ex-racing dogs is also widely recognised. Greyhound musculature (muscles and tendons) differs from other breeds and through selective breeding and their training regime has been specialised for speed, aerobic stamina, and a wide range of spinal motion.

When adopting an ex-racing dog, understanding how the dog’s muscles have been developed for racing helps new owners recognise and treat the potential sites of soft tissue injury, so their new family member can happily settle into their new life.

Here are some of the muscles groups that have been developed in racing Greyhounds for speed and acceleration. When I treat ex-racing greyhounds, these body areas are often tense, sensitive, and hypertrophied from overwork.

Spinal muscles

Greyhound’s spinal muscles play several roles in the dog’s movement. Firstly, they maintain the structural integrity of the dog’s vertebral column by stabilising the spine. The longissimus dorsi muscle which lays along most of the length of the vertebral column protects and stabilises the spine from hyper-flexion and movements that may exceed its normal range of motion.

Secondly, they facilitate co-ordinated limb movement by transferring substantial power to both the forelimbs and hindlimbs during locomotion. Specifically, the longissimus dorsi and iliocostalis lumborum muscles are specialised for power production for high speed locomotion and rapid accelerations. The power produced through the spinal muscles facilitates the hip extensors muscles to lengthen the dog’s stride during the aerial phase of the gallop.

Additionally, several muscles of the shoulder and cervical region that insert or originate on the ribs facilitate locomotion. They also have a role in ventilation. These muscle expand the thoracic cavity by rotating the ribs cranially and laterally to assist inspiration when the dog is galloping.

Hip extensors and flexors

The pelvic limb in Greyhounds is specialised for high power output specifically the hip extensor muscles. These muscles in the racing Greyhound are a source of power required to accelerate the dog’s centre of mass.

In racing Greyhounds the hindlimb muscles are often hypertrophied particularly in the upper (proximal) part of the limb. The heaviest muscle in the hindlimb is the femoral bicep which comprises approximately 18% of the hind limb muscle mass. The femoral biceps and semitendinous in racing greyhounds is about double the relative mass compared to “normal” dogs. It is these muscles along with the adductors that extend the hip and hind leg that provide Greyhounds with their acceleration capability. Other muscles that contribute to hip movement are the gluteals and semimembraneous.

Stifle flexion and extension

Muscles that generate the greatest amount of power in the stifle joint include the semimembraneous, the vastus group of muscles and rectus femoris.

Tarsal extensors

The torque generated through the tarsus joint is thought to be due to Greyhound’s muscle and tendon architecture. The main tarsal extensor muscle is the gastrocnemius. The length of the gastrocnemius tendon plays a pivotal role in tarsal joint movement by transferring and amplifying power for acceleration.

These four muscle groups (spine, hip extensors, stifle flexors and extensors, and tarsal extensors) are typically hypertrophied and tense in ex-racing Greyhounds. In my practice, these are the main body areas on which I focus my treatment with a view to reducing muscle tension and treating any trigger points.

If you are adopting or even fostering a Greyhound during this Adopt a Greyhound month, then please give me a call to book a treatment and help ease your new family member into their new life. Full Stride provides canine myofunctional therapy treatments in your home or at my clinic on the north side of Brisbane.

Until next time, enjoy your dogs.

Sources:

Webster, E. L., Hudson, P. E. and Channon, S. B. (2014), Comparative functional anatomy of the epaxial musculature of dogs (Canis familiaris) bred for sprinting vs. fighting. J. Anat., 225: 317–327. doi:10.1111/joa.12208

Williams, S.B, Usherwood, J.R, Jespers, K, Channon, A.J and Wilson, A.M. (2008) “Exploring the mechanical basis for acceleration: pelvic limb locomotor function during accelerations in racing greyhounds (Canis Familiaris)” The Journal of Experimental Biology 212: 550 – 565

Williams, S. B., Wilson, A. M., Rhodes, L., Andrews, J. and Payne, R. C. (2008), Functional anatomy and muscle moment arms of the pelvic limb of an elite sprinting athlete: the racing greyhound (Canis familiaris). Journal of Anatomy, 213: 361–372. doi:10.1111/j.1469-7580.2008.00961.x