Sadly we don't have the ability to ask our dogs exactly how they're feeling, so we can't know exactly how they experience pain. We can assume from observation that different dogs have different pain thresholds, and we do know from human experience that different injuries or injury sites, will cause different levels of pain.
Following a recent fall in snow (note to self: don't walk three dogs on lead down a hill when it's icy) I now have a stain to my left Tricep. So while I may be guilty of a little anthropomorphism here, since we know that canine and human muscles are constructed and function in the same way, I thought I'd reflect on my experience to think about how our dogs may feel and the symptoms they show.
What is a strain?
A strain is an injury to a muscle, involving tears to the muscle fibres. A grade one strain typically affects up to 10% of the muscle fibres, and we may just experience these as a slight ache or discomfort without knowing exactly what happened. A grade two strain can affect around 50% of the muscle fibres. Symptoms can include brusing, swelling, heat, pain on touch and reduced mobility. A grade three is a rupture of the muscle.
What can cause it?
It can be a sudden impact or trauma, a sudden overstretching of the muscle, or can be cause by gradual wear and tear, particularly when muscles aren't given the recovery time they need. I have a grade two strain caused by sudden trauma when I fell on my outstretched arm, with my elbow and tricep taking the impact.
How did it feel?
I thought I'd broken my arm. I screamed, I may have sworn a little, and then lay on the ground wondering how to get up while three dogs stared at me wondering if this was a new game! In your dog a sudden trauma could be seen with vocalisation, suddenly pulling up from exercise, and sudden onset lameness. A strain through wear and tear is tougher to spot as it comes on gradually, meaning our dogs overcompensate and adapt to the pain.
My arm is purple and swollen and warm to touch. I have full mobility in my shoulder but with some pain, however I can't fully extend my elbow. I can't lift anything heavy or push anything. In your dog you may see lameness and not fully weightbearing. Depending on the breed and injury site you may see some bruising. The area may be swollen and warm to touch, and your dog may react to touch. They may avoid certain activities such as using the stairs, or even be reluctant to exercise.
During the acute phase you will need to rest and restrict mobility as much as possible, and apply ice to the affected area. Your vet may prescribe anti inflamatories if your dog is experiencing pain.
I'm now out of the acute phase, but that doesn't mean that the injury has healed or that the pain has gone.
I keep forgetting the pain - when I'm not thinking about it I go to use the arm as normal and feel a sudden twinge. I swear again! Your dog may see a rabbit and go to run. You could see them pull up suddenly and yelp, or if adrenaline takes over they'll run and chase as normal, but then appear stiff and lame later on.
I have limited function and have adapted what I do. Certain things either hurt or aren't possible. I am struggling to change gear when driving, can't lift with my left arm, and even getting dressed hurts. Your dog may struggle with some of their activities of daily living. They may have difficulty getting on and off furniture, or jumping in the car, and they may slow down or avoid exercise.
I am overcompensating. I am using my right arm more, and hardly moving my left which means I can even feel that I'm walking differently and other muscles are aching. I'm sleeping differently and now have a painful neck as a result. Your dog will place more weight through their other limbs. We then start to see strains, trigger points and myofascial pain in the muscles that are taking more of the load. Typically we see overcompenation in diagonal limbs, but not always.
Trigger points are forming. I have identified at least two. These are hyper irritable focal points. The muscle trauma has caused the muscle to spasm, which causes ischaemia (lack of arterial blood flow), which causes further pain and spasming, and trigger points form in the area as a result. Your dogs muscles function in the same way.When I identify a strain I nearly always find trigger points nearby.
I am grumpy! Ongoing pain is annoying and very wearing. Feeling a constant dull ache now, and adapting what I'm doing has made me irritable and just very fed up. In your dog you may see this as them appearing lethargic and losing enthusiasm for normal activities. You may also see them being less sociable with dogs and people, and avoiding stroking or grooming.
How do we treat a strain?
As mentioned for the first 72 hours plenty of rest and ice is needed. Then in the sub acute phase massage can help to remodel scar tissue that forms as the muscle heals, as well as relieving overcompensatory issues. The earlier the scar tissue can be worked on, the more supple the muscle fibres in that area will be. To leave it too long will result in the scar tissue being less flexible, which in turn restricts mobility and can cause myofascial pain to develop.
I'll personally be having a sports massage in about a week as soon as I can tolerate the pain. In the meantime I'll mostly be found trying not to use my arm too much, and moaning about it of course!