What's the Difference Between a Grade 1, Grade 2 & Grade 3 Injury?

Written by Scott Gentle
Physiotherapist, University of Queensland
Medically reviewed by Dr Gina Arena
Research Fellow, University of Western Australia
Reviewed on March 12, 2022
Contributed by Leon Mao
Physiotherapist, University of Melbourne

Physiotherapist sitting on a treatment table making notes on a clipboard

The grading of injuries can be classified numerically from 1 to 3. Grade 1 typically represents more minor injuries, grade 2 with more extensive damage and grade 3 are the most significant.

Conditions, such as sprains and strains, generally have a classification to describe the severity of the injury. As noted earlier, the higher the grading number, the more severe the injury tends to be.

How many grades are there?

These classifications of grade 1 vs grade 2 vs grade 3 injuries are commonly used to judge the severity of the conditions. However, other conditions may even have more grades. For instance, patella chondromalacia is a condition where the cartilage behind the kneecap begins to wear. Unlike other types of injuries, its severity classification ranges from grades 0 to 4 instead.[1].

Grade 1 Strains

Grade 1 strains typically describe a mild muscle injury where the muscles have primarily been overstretched with a 5% loss in function. Individuals will notice some swelling, tightness, pain and loss of flexibility through the affected muscle.[2].

Grade 2 Strains

Grade 2 muscle strains tend to describe a moderate injury where some muscle fibres are torn with a 5-50% loss in function. Those diagnosed with grade 2 strains will notice more severe symptoms compared to grade 1 strains. Loss of flexibility, additional pain, and bruising are often seen in these types of injuries.

Grade 3 Strains

Grade 3 strains are the most severe types of injuries which lead to a complete tear or rupture of the affected muscles. More than 50% off function will be lost when this occurs. Severe pain, swelling, bruising and tenderness over the muscle can be felt when grade 3 strains arise.

Diagnosis of Strains

The grading of conditions will often depend on its structure and location. Health professionals will look at the grading to determine how significant the injuries are. Sometimes, this information can be diagnosed through a thorough physical examination. However, the best way to identify these gradings is through radiological imaging (e.g. X-rays, ultrasounds, MRI scans, etc.).

Why do we have grading systems?

These grading systems are a universal way for health professionals to communicate with other parties (e.g. patients, health professionals, etc.) about the severity of the injury. Treatments and approaches to the condition may depend on these grades. For example, mild to moderate grade injuries may only require physiotherapy to assist with recovery. In comparison, referrals or strategies (e.g. involving orthopaedic specialists, bracing, etc.) may be required for more substantial injuries.

Types of injuries

Types of injuriesSpecific injuriesNumber of grades
Tendon or muscle strainsGrade 1, 2 and 3
Hamstring strains
Quadricep strains
Rotator cuff strains
Calf strains
Adductor or groin strains
Achilles ruptures or strains
Patella tendon rupture or strain
SprainsGrade 1, 2 and 3
Ankle sprains
Knee ACL sprains or ruptures
Knee LCL/MCL sprains or ruptures
Wrist sprain
Back sprain
Cartilage injuriesModified Outerbridge Grading [2], Grade 0, 1, 2, 3 & 4
Chondromalacia patellae of the knee
Cervical spondylosis
Costochondritis of the ribcage
Knee joint
Shoulder joint
Hip joint
Open FracturesGustilo Anderson Classification [3], Grade 1, 2, 3a, 3b, 3c
Humerus fractures
Tibia fractures
Fibula fractures
Radial and ulnar fractures
SpondylolysthesisMeyerding’s Classification [4], Grade I, II, III,IV
Anterolisthesis of the cervical and lumbar spine
Retrolisthesis of the cervical and lumbar spine
Herniated discsStage 1, 2, 3, 4
Lumbar spine
Cervical spine

Causes related to Injury Grading Classifications

There are many reasons for some injuries to be classified higher or lower. Most of these classifications are given after an imaging (e.g. CT scan, MRI, x-ray, etc.) of an injured area. Radiologists will read the scan and use their clinical expertise to determine the grading. More significant looking injuries on the scan will often correlate with higher grading classifications. However, grading classifications can be misleading as they do not always match the symptoms of presentation. While imaging techniques are helpful, the results can be subject to the quality of the scan, the experience of the radiographer/radiologist and limited in the angles examined.

There are several causes why some injuries are more severe than others, including:

  • Pre-existing conditions (e.g. osteoporosis, osteoarthritis, etc.)

  • Type and intensity of the trauma

  • Occupation and lifestyle behaviours

  • Repeat injuries to the same area

  • Force of the injury mechanism

  • Age

5 tips regarding grading severity (recommended by a physiotherapist)

Injuries may need to be properly graded to ensure optimal recovery and rehabilitation. Management of a condition will often depend on how severe the symptoms and grades are. Here are five physiotherapist recommended tips to assist you with your injury's aches and pain.

  1. Get a proper diagnosis from a health professional, such as a physiotherapist or GP. Depending on your symptoms and/or presentations, you may need to get imaging to determine your injury's severity.

  2. Generally, mild to moderate injuries (grades 1 to 2) will successfully recover over time with physiotherapy, rehabilitation and pain management strategies.

  3. Severe injuries (grades 3 to 4) may require a referral to a specialist and more invasive treatment (e.g. period of complete rest, injections, etc.) on top of physiotherapy.

  4. A period of temporary rest or reduced movement is recommended for any injury grading to encourage recovery.

  5. Active at-home recovery strategies should be considered while awaiting diagnosis and seeking medical expertise. Examples include bracing and crutch (if required), using ice or heat, sufficient sleep (at least >7 hours sleep) and reducing activities that cause any irritation.


Grading classifications are helpful as they provide an outlook for injuries. Higher gradings may require a specialist opinion, while lower gradings are more manageable through conservative management like physiotherapy. However, grading classifications are only one perspective of your condition. Medical reasoning should be combined with grading classifications to provide an accurate overview of any injuries.

Written by Scott Gentle
Physiotherapist, University of Queensland
Published on March 13, 2022
Medically reviewed by Dr Gina Arena
Research Fellow, University of Western Australia
Reviewed on March 12, 2022
Contributed by Leon Mao
Physiotherapist, University of Melbourne
Medical reviewers
Last medically reviewed on March 12, 2022
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