Anyone working in sporting environments would be very familiar with acute muscle injuries.
So how prevalent are they?
It’s been reported that a male elite-level soccer team with a squad of 25 players can expect about 15 muscle injuries each season¹. This equates to an average absence time of 223 days, 148 missed training sessions and 37 missed matches!¹
Despite how often people present with muscle injuries, how confident are you are diagnosing and classifying these injuries?
To be honest, I’ve had trouble over the years confidently grading a muscle injury, especially early in my career when I hadn’t seen many examples.
This widespread difficulty in the clinical setting was perhaps the impetus for a collaborative review of muscle injury classification, via a survey and analysis of 30 sports medicine practitioners thoughts in 2012.
What followed was an open-access publication² in the British Journal of Sports Medicine, which might be the most comprehensive guide for more accurately classifying muscle injuries.
The following is a summary of some of the concepts.
The healing time frames and principles of management more based on my experience.
 
Source: A great website!
http://physiodevelopment.com/classification-muscle-injuries-in-sport/

Classification of Acute Muscle Injuries in Sport

Broadly, a muscle injury can be classified as indirect or direct.
Indirect refers to an internal disruption to a muscle, without any external force/trauma involved.
Direct refers to any trauma (blunt or sharp) that impacts the muscle externally.

Indirect Muscle Injuries

Indirect muscle injuries can be sub-classified as a:
•functional muscle disorder, or
•structural muscle injury.

Functional Muscle Disorder

These can be further classified into the following:
•Type 1: Overexertion-related muscle disorder •Type 1A: Fatigue-induced muscle disorder
•Type 1B: Delayed-onset muscle soreness (DOMS)
•Type 2: Neuromuscular muscle disorder •Type 2A: Spine-related neuromuscular muscle disorder
•Type 2B: Muscle-related neuromuscular muscle disorder

Overexertion-related Muscle Disorder

Type 1A: Fatigue-induced muscle disorder:
•Increase in muscle tone (tightness or firmness) due to overexertion
•Diffuse, tolerable pain, involving up to the whole length of a muscle
•Imaging: clear
Healing Time Frame (approximate)
Less than 7 days.
Management
•Emphasis is on recovery (massage, ice baths, stretching)
•Prevention: •Warming up prior to exercise
•Maintaining good muscle length (stretching)
•Eccentric exercise and conditioning

Type 1B: Delayed-onset muscle soreness (DOMS):

•Generalised pain after unaccustomed eccentric exercise
•Swelling/oedema
•Pain at rest, as well as on isometric contraction
•Imaging: negative, except for oedema
Healing Time Frame (approximate)
Less than 7 days.
Management
•Emphasis is on recovery (massage, ice baths, stretching)
•Prevention: •Warming up prior to exercise
•Maintaining good muscle length (stretching)
•Eccentric exercise and conditioning

Neuromuscular Muscle Disorder

Type 2A: Spine-related neuromuscular muscle disorder
•General ache, with increase in muscle firmness.
•Occasional sensitivity of overlying skin
•No pain at rest
•Imaging: clear, possible oedema
Healing Time Frame (approximate)
Less than 7 days.
Management
•Principles of muscle retraining •Maintain or improve muscle length
•Improve strength (especially eccentric)
•Address any deficit in motor control (functional lower limb)
•Progress with sports-specific retraining
•Addressing any symptoms of lumbar spine dysfunction •Inflammation or irritation around lumbar nerve roots
•Treating any low back movement dysfunction or motor control disorder

Type 2B: Muscle-related neuromuscular muscle disorder

•Cramp like description of pain
•Increase in muscle tone
•May result from dysfunctional neuromuscular control (e.g., reciprocal inhibition)
•Imaging: clear, possible oedema
Healing Time Frame (approximate)
Less than 7 days.
Management
•Principles of muscle retraining •Maintain or improve muscle length
•Improve strength (especially eccentric)
•Address any deficit in motor control (functional lower limb)
•Progress with sports-specific retraining
•Retrain any dysfunction in agonist/antagonist muscle function •Are there adjacent muscle groups that are inhibiting the affected muscle, or contributing to an increase in muscle tone?
Structural Muscle Injury
These can be further classified into the following:
•Type 3: Partial muscle tear •Type 3A: Minor partial muscle tear
•Type 3B: Moderate partial muscle tear
•Type 4: (Sub)total tear

Partial Muscle Tear

Type 3A: Minor partial muscle tear:

•Tearing of small muscle fascicle or bundle
•Sharp pain and sudden onset of injury
•Localised pain, with possible defect on palpation
•Stretching induces pain
•Very often musculotendinous junction
•Often minimal loss of muscle strength
•Imaging: Positive disruption on MRI, with intramuscular haematoma
Healing Time Frame (approximate)
14-21 days
Management
•Optimise environment for healing, based on the stage of tissue recovery
•Maintain or improve muscle length
•Improve muscle strength (especially eccentric)
•Address any deficit in motor control (from a functional perspective)
•Sports-specific retraining and improve overall conditioning

Type 3B: Moderate partial muscle tear

•Tearing of greater diameter than the muscle fascicle or bundle
•Sharp, localised pain at onset of injury
•Possible fall of athlete
•Well defined, localised pain
•Palpable defect in muscle
•Stretching induces pain
•Definite loss of muscle strength and function
•Imaging: Positive with significant fibre disruption, possible retraction, and intermuscular haematoma
Healing Time Frame (approximate)
4-6 weeks.
Management
•Optimise environment for healing, based on the stage of tissue recovery
•Maintain or improve muscle length
•Improve muscle strength (especially eccentric)
•Address any deficit in motor control (from a functional perspective)
•Sports-specific retraining and improve overall conditioning

Type 4: (Sub)total muscle tear / tendinous avulsion

•Tear involving complete diameter of muscle, or tendinous avulsion from bone
•Localised dull pain at onset
•Athlete often falls
•Considerable defect in muscle
•Muscle retraction
•Considerable loss of function
•Haematoma
•Imaging: Subtotal/complete discontinuity of muscle/tendon, intermuscular haematoma
Healing Time Frame (approximate)
A minimum of 12 weeks.

Management

For complete tears, a much slower and extended rehab process follows, guided by pain and changes in muscle tone. The same principles still apply:
•Optimise environment for healing, based on the stage of tissue recovery
•Maintain or improve muscle length
•Improve muscle strength (especially eccentric)
•Address any deficit in motor control (from a functional perspective)
•Sports-specific retraining and improve overall conditioning
Surgery is advocated for complete tendon avulsion, followed by postoperative rehabilitation.

Direct Muscle Injuries

The main type of direct muscle injury to note is a contusion. This is characterised by:
•Direct trauma to muscle by an external force
•Haematoma, causing loss of mobility and function
•Imaging: Diffuse oedema and haematoma at sight of trauma

Healing Time Frame

In the absence of any structural damage, an athlete can often continue playing. If there is any associated muscle fibre disruption, then healing will be based on the severity of the indirect muscle injury (see above).

Management

Again, if there is no structural damage, just localised swelling and oedema, the emphasis is on recovery. Acute management of swelling and haematoma.
Additional Notes
•Healing time frames and management will vary slightly depending on the muscle group involved.
•Risk factors for injury will play an important role, for example (but not limited to): •Age, previous history of muscle injuries, level of competition, physical conditioning, and fatigue³.
References
1.Ekstrand J, Hagglund M and Walden M 2011, ‘Epidemiology of muscle injuries in professional football (soccer)’, American Journal of Sports Medicine, vol. 39, pp. 1226–32.
2.Ueblacker P et al 2013, ‘Terminology and classification of muscle injuries in sport: The Munich consensus statement’, British Journal of Sports Medicine, vol.47, pp.342–350.
3.Bruckner P et al 2014, ‘Recurrent hamstring muscle injury: applying the limited evidence in the professional football setting with a seven-point programme’, British Journal of Sports Medicine, vol. 48, pp. 929-938.