Agility is a physically demanding sport and has developed greatly over the years. Dogs are getting faster, and courses are becoming more challenging to navigate. Most courses have fifteen to twenty obstacles and require the dogs to jump, run, weave, balance and turn as accurately and as fast as possible.
The physical demands we place on are dogs is huge!
With the agility season seemingly in full swing (it gets earlier and earlier every year) many of my clients have been proactive in ensuring their dogs receive their pre-season muscular health check and maintenance massage treatments. However, with faster speeds and more challenging courses, their is still potential for injury.
Statistics suggesting that 41.7% of agility dogs will suffer an injury (Markley, 2021)
That’s around 1 in 3. To put that into perspective if you run 3 agility dogs one is likely to sustain an injury or if you attend shows with two of your best friends one of you is going to be out of the game for a while. A sobering thought, which is why this first blog of a two part series looks at the three most common injuries in agility dogs and how they can occur.
Muscle and Movement
The most common injuries treated in agility dogs are injuries to the soft tissue (muscles, tendons, and fascia). Muscle accounts for 45% to 50% of a dog’s body weight. It largely consists of skeletal muscle which is constructed entirely of individual, elastic, muscle fibres which are arranged into fascicles (bundles). The fascicles are then gathered together to form the main belly of the muscle. Muscle thins at each end to form tendons which attach the muscle to bone. Skeletal muscle produces immense power and movement by repeated contraction and relaxation. Healthy muscle ‘slides and glides’ making movement look effortless, fluid, smooth, elastic, co-ordinated, rhythmical, symmetrical, and balanced.
Soft Tissue Injuries
Injuries occur in agility due to the high impact and repetitive strain nature of the sport i.e. jumping, fast tight turns, weaves and contacts. Repetitive Stress injuries (RSI) cause micro-tears to the muscle. Micro-tears are so small that they usually go unnoticed as they do not seriously impact the dog’s mobility or performance. However, micro-tears can build up quickly causing restrictive adhesions (scar tissue) between the muscle fibres. Areas of tissue can become so adhered that it prevents the effortless slide and glide movement of the muscle fibres. At this stage several things may happen if left untreated.
Trigger points – Where larger areas of adhesions form over-time, they can form a trigger point (A hyperirritable band of focal point tension whereby the muscle fibres have stayed in a contracted, adhered state).
Hypertonicity – persistent stress and overuse can cause the muscle to maintain a constant state of mild contraction (too much resting tone). A hypertonic muscle is inflexible and will require more effort than is necessary to produce movement.
Chronic strain – continuous, prolonged overuse and repetitive movements will continue to create micro-tears within the muscle. The muscle fibres will become weaker until they eventually tear.
Acute strain - A direct trauma (accident), such as a sudden impact, fall, twist or sudden acceleration or deceleration that the body is unprepared for, will cause the weakened muscle fibres to become overloaded as they are forced to over contract and stretch, reaching a breaking point causing an instant tear.
There are varying degrees of strain graded 1-4. It depends on how many muscle fibres have been torn to the severity of the injury and how long the injury will take to heal. Muscle takes 6 to 8 weeks to heal, tendons 4 to 6 months.
Common sporting injuries
In agility dogs, the areas where you get the most, soft tissue injuries tend to be the shoulders, back and hip flexors. Let's take a closer look at each injury.
1.Shoulder
The scapula is a large flat bone which articulates with the Humerus to form the shoulder joint of the forelimb. Forelimbs are designed to support, absorb shock on landing, decelerate when turning/stopping and changing direction. Dogs bear around 60% of their body weight on their forelimbs when standing. However, on landing after a jump the forces are 3-5 times greater than the dog’s body weight. I will let you do the math!
The dog's shoulder joint is highly mobile, as unlike humans, dogs do not have a clavicle (collar bone) to support the shoulder girdle. Their scapulae are attached to the body via muscles, tendons, and ligaments (muscle sling). This allows dogs to run and cover great distances quickly but in doing so also makes them more susceptible to injury.
A recent study (Markley, 2021) stated the most common injury experienced by agility dogs was to the shoulder (30.1% of reported injuries). This includes,
Biceps tendinopathy – repetitive use or overloading can cause the biceps tendon to become tight, causing inflammation and dysfunction.
Medial shoulder instability – repetitive sprain injury to the shoulder ligaments and/or strain injury to the muscles of the shoulder joint causing instability.
Supraspinatus tendinopathy – a repetitive strain injury causing the tendon of the supraspinatus (muslce of the shoulder) to become tight, causing inflammation and dysfunction.
2. Back
Back injuries are the second most common injury in agility dogs after shoulder injuries. The epaxials are a group of muscles that attach dorsally to the transverse processes of the vertebra. The are arranged in three longitudinal groups along the length of the spine. The deepest muscle is the Multifidius, a thin, stabilising muscle. The Longissimus and Iliocostalis are movement muscles enabling the spine to extend and laterally flex. An over developed movement muscle causes the Multifidus to become underdeveloped. Research in humans shows that weakness in the Multifidius causes the Longissimus to spasm. Core conditioning is essential to strengthen the Multifidius and to reduce reoccurring back pain and risk of injury.
The Iliocostalis Lumborum, is associated with the lumbar spine (lower back). It enables the spine to extend and produce lateral movement to the lumbar spine when contracted on one side. The Iliocostalis Lumborum can become injured in the following ways.
Overworked - if the muscle is overworked due to intense exercise or the dog not using their body correctly (incorrect posture or form) it can become over developed and hypertonic (tight) which restricts movement. This causes the muscle to fatigue quicker making it more susceptible to injury.
Flexibility - The lumbar spine can flex and extend by over 50 degrees in the gallop, enabling huge length of stride. This is of great advantage in agility, however unlike other sections of the spine the lumbar doesn’t have a ribcage or a pelvis to support it so it is more at risk of injury.
Junctions of the spine – The spine is split into five distinct regions: cervical, thoracic, lumbar, sacral and caudal. Each region has a set number of vertebrae and is written as the following formula: C7 T13 L7 S3 Ca20. The back is more susceptible to injury at the junctions i.e the thoracolumar region (junction between thoracic and lumbar) and lumbarsacral region (junction between lumbar and sacral). These junctions are more prone to injury as it's where more stable areas of the spine meet less stable areas.
3. Iliopsoas
The Iliopsoas is a combination of two muscles, the Psoas Major and Iliacus. These muscles originate from the ventral aspect (underside) of the lumbar vertebrae and iliac crest (wing of the pelvis) and insert onto the lesser trochanter (bony landmark on the inside of the femur). The Iliopsoas is the main hip flexor and major adductor of the hindlimbs. It also helps to stabilise the spine and hip.
This powerful muscle is used repetitively in agility, so it is no wonder why it is susceptible to RSI. Jumping or movements with great hip extensions can aggravate the Iliopsoas causing the muscle to ‘adaptively shorten.’ The muscle will become inflamed, tight and painful to stretch, resulting in knocked poles and shortening of stride, with the hindlimbs not fully extending behind them. This is more noticeable at speed and when jumping. The dog’s posture may also change displaying a roached back and pacing hindlimbs more underneath the body.
The Iliopsoas can also be “overstretched” suddenly (acute strain) if your dog loses its footing while running or abruptly changes direction. In essence the dog does the splits. Weak core muscles, lack of warm up, inflexibility, lack of conditioning and muscle fatigue can all be contributing factors to an Iliopsoas injury.
A recent study showed 80% of Iliopsoas injuries are secondary/ compensatory injuries. So, there will be another primary injury! This is why it is so important your dog has a full body examination when a Iliopsoas strain is suspected.
Summary
Research helps us to understand the factors that contribute to agility injuries, and enables us to potentially avoid our dogs sustaining an injury whilst doing the sport they love. However it is important to set them up for success, by preparing them for any challenges they may face when training or competing. This is why in my next blog I will be talking about why a multi-modal approach is vital to help prevent your agility dog from sustaining an injury.
If you ever have a concern about your sporting dog’s physical ability, please get in touch. I am more than happy to talk about any concerns that you may have and help you reduce the risk of injury for your dog so they can play agility safely!
References
Canine Conditioning Academy - www.canineconditioningacademy.co.uk
Canine Conditioning Coach - www.canineconditioningcoach.com
Canine Massage Guild - www.k9-massageguild.co.uk
Canine Massage Therapy Centre - www.k9-massage.co.uk
Markley, A. P. et al. (2021). Internet-based survey of the frequency and types of orthopedic conditions and injuries experienced by dogs competing in agility, Journal of the American Veterinary Medical Association https://avmajournals.avma.org/view/journals/javma/259/9/javma.259.9.1001.xml