Consequences of soft tissue injury

Just a short-ish post today on the consequences of soft tissue injury and recovery times for some common soft tissue strains that plague the distance runner.

Some of the most common soft tissue strains for runners occur in the lower limbs for good reason. The muscles of the quadriceps (front of thigh), hamstrings (back of thigh) and calf muscles (back of lower limb) are the muscles that power the gait cycle along with the gluteal complex (pelvic region). Of course, this is certainly not an exclusive list, however as these are the muscles that help to propel us through the gait cycle they are prone to overuse injuries.

Soft tissue strains most commonly occur either in the belly of the muscle or at the musculotendinous junction. The musculotendinous junction is an area of weakness where the more elastic tissue of the muscle form a 'junction' with the dense tendon tissue which is relatively inextensible. The creates an area of vulnerability for the runner.

Acute v Chronic

Soft tissue strains can occur acutely or chronically. The acute scenario usually occurs with greater speeds and acceleration and is usually felt as a 'grab' or a 'pull' enough to halt the runner's progress. More chronic forms can occur over the duration of a single training session or over the cause of a number of training sessions where tissue overload is greater than the recovery time. Strains do not warm up to any great extent as the injury is one of inflammation and fibre disruption/separation. If you try to continue it will simply get worse.

Grades

There are generally grades of soft tissue strain (grades 1, 2 and 3). Usually with a grade 1 there is minimal disruption to the fibres and only minor dysfunction often felt at the time of activity or shortly after. If training is not modified or ceased at this stage a grade 2 progression might be the case!! If a grade 2 strain is sustained there will often be marked dysfunction (running will not be possible) there may be swelling at the site and there will be pain with passive and active contraction/extension of the soft tissues involved. If you are unlucky enough to sustain a grade 3 there will be immediate pain and severe dysfunction at the site and you will often need imaging to determine the extent of the injury and exact site involved. Surgery may be required. There are often large forces and accelerations involved with these injuries.

Common sites of strain for the distance runner

• Medial head of gastrocnemius (medial portion upper calf)
• Junction between gastrocnemius and soleus (calf junction)
• Biceps femoris - long head (back of thigh)
• Rectus femoris - middle to upper portion (middle front of thigh)
• Adductor longus - (inner thigh) 
• Strains of the glutes and smaller muscles of the outer pelvic region do occur however they are far less common being more prone to instability problems

Treatment

In the case of an overuse strain the causative factor must be considered. For example in the case of an overuse calf strain, treatment at the site of pain without looking remotely simply will not address the problem effectively. There must be consideration to a variety of factors including (but not limited too), pelvic position (huge factor), trunk rotation, hip stability, mobility about the SIJ and hips, knee/foot positioning, pronation, ability of the foot to maintain stability. As you can see looking at the site of injury only is an isolated view and in the case of running an overall assessment is needed.

Initial treatment needs to focus on reducing pain and swelling with the use of ice and pain free range of movement for the first 48 hrs. At this time pain free range of motion and static stretching can occur. After 5-6 days for a grade 1 and 1-2 weeks for a grade 2 strengthening can occur with a focus on controlled eccentric training with a gradual progression to more dynamic exercises. This must be progressive.

It is really important in the early stages (as discussed in a previous post) to resist the temptation to take anti-inflammatories. There may be other options you can discuss with your GP or sports physician if it is pain you are concerned about.

Soft tissue therapy or physiotherapy should be addressed in the first few days to assess severity of injury and assessment of the causative factors. Remember strains don't just occur there is often a 'driving factor'. This may address the factors described above depending on what the assessment outcomes are.

Prognosis (guide only)

Grade 1 − 10-12 days followed by a graduated program

Grade 2 − 16-21 days followed by a graduated program

Grade 3 − 3-6 months depending on severity and surgery. An intensive rehab program and a monitored program is usually advised.

Consequences

One of the biggest risk factors for a soft tissue strain is if you have sustained this type of injury before. In other words if you have had a calf strain you are at a greater risk of sustaining another than if you had not sustained one in the first place.

During the recovery period the initial inflammatory process dominates the first 48-72 hrs, during this time the scene is set for further healing. From approx. 48hrs continuing for the next 4-6 weeks fibroplasia is the dominating factor with type 3 collagen filling the fibre disruption by almost 'plugging the tear'. This is extremely important in laying down a fibrous network until the remodelling process takes over. During this time it is extremely important to keep a progressive load through this tissue without causing further disruption.

As a load is applied through the soft tissue in the line of fibre direction the tissues align themselves accordingly ie; for a  hamstring strain a longitudinal load needs to be applied to allow strength adaptation in that plane. To simplify, you need to load in the fashion in which you will use it! This is the time you will often see eccentric exercises being used in a progressive fashion.

Once a load is placed through the healing tissue greater strength and fibre alignment occur. The tissue of greatest interest in fibrous tissue formation is type 3 collagen which is a thick, dense non contractile tissue with relative inextensibility. It initially runs a non uniformed direction unless a progressive load is placed upon it, hence the importance of a progressive loading program. This creates a more mobile scar.

Further help in creating more mobility through this tissue can be achieved through local soft tissue mobilisation about 3-4 weeks after the initial injury. Treating the site before this time risks further rupture between the collagen bundles as the tissue is relatively weak and immature. This type of treatment is quite deep and creates a local anaesthesia (and a little post treatment soreness the next day).

The final stage of healing from approx 3-4 weeks onwards is remodelling of the soft tissues and continues long term until the tissue are fully healed. This may take anywhere from 12 weeks to 18 months depending on the severity of injury and the adherance to a progressive rehab program. The long term outcome is usually a more compliant tissue and a smaller scar that accepts greater loads.

In summary the consequence of poor adherance to a progressive program is a less mobile, thickened tissue that has decreased strength and an increased risk of re-injury.

As you can see even with a grade 1 tear there is reason to continue rehab past the initial return to run program - something us runners are usually poor at!

Can you reduce your risk?

There are a couple of things that you can do to reduce the risk of a soft tissue strain. Knowing the trigger(s) often helps. For example if you know that every time your right glute medius (side of hip) starts to fatigue that your right calf tends to overwork, then you can self treat this accordingly.

If you know a good soft tissue therapist/physio/osteo/sports physician who can go through a musculoskeletal screening and address imbalances this may help. Alternatively a gait assessment can often achieve good results given that changes to gait can be made. Lastly, regular treatment can self assess/therapist assess certain changes in the relevant soft tissues. This acts as a warning to the runner.

If you are the type of person who is generally 'stiff' or suffer with lack of mobility from soft tissue 'stiffness' then you may be more of a candidate for soft tissue strains particularly in the belly of the muscle. Those who are the more mobile types with larger ranges of motion tend to be more succeptible to jointy type pathologies.

To summarise some of you treatment options

• Rest/load modification
• Ice 24-48 hrs as often as possible for 15 mins 
• Gentle pain free passive and active movement (this will help with swelling)
• Pain free stretching after 5 days can occur, depending on the grade
• Soft tissue treatment dealing with the causative factor
• Progressive strengthening program (timing depends on the grade)
• Self management/treatment techniques (focusing on known triggers for certain areas)
• Local soft tissue mobilisation (3-4 weeks post injury)
• Graduated return to running program

Until next time,

Jimmy