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Muscle Tears Cheat Sheet (DRAFT) by

Pathophysiology, recognition and treatment of muscle tears.

This is a draft cheat sheet. It is a work in progress and is not finished yet.


Grade I (mild strain): limited number of fibres, no decrease in strength, full AROM and PROM
Grade II (moderate strain): nearly half the muscle fibres torn, swelling, minor decrease in muscle strength
Grade III (severe strain): complete rupture, severe swelling and pain, complete loss of function

Healing Process

Inflam­mation Days 1-4
Necros­is/­apo­ptosis of injured fibres, hematoma, phagoc­ytosis, early fibroblast activity to form ECM
Prolif­eration Days 4-Week 4
Fibrob­lasts invade ECM. They stabilize tissues and create scaffold for new muscle fibres. Satellite cells activated which stimulate myoblast formation. Myoblasts build new muscle fibres (myotubes)
Remode­lling Weeks 4-12
Disorg­anized matrix into organized matrix, revasc­ula­riz­ation and muscle innerv­ation occur at later stages

Healing Timeline



High force or decele­ration when in the stretched position
Repetitive or increased motions

Factors Predis­posing Muscle Strain

Inadequate warm up
Insuff­icient joint ROM
Excessive muscle tightness
Fatigu­e/o­ver­use­/in­ade­quate recovery
Muscle imbalance
Previous injury
Faulty techni­que­/bi­ome­chanics
Spinal dysfun­ction

Subjective Questions

Loss of sensation? Infection red flags?
What happened after injury? Swelling? Bruising? Redness?
Noise when it happened? Able to play on?
Changes in duration, intensity or freq of activity?
24 hour pattern? WB?

Objective Assessment

Swelling, bruising, or redness
Painful to palpate, may feel tear
Pain with AROM but not PROM indicative of muscle injury
Decrease w movement (Grades II-III)
Functional Tests
Pick up mug, brush teeth, STS, Squats

Early Rehab (0-2 Weeks)

Immobi­liz­ation (severity depend­ent). First few days after injury only.
Gentle mobili­zation and ROM (midra­nge), severity dependent. Avoid aggressive stretc­hing.
Gentle massage for scar tissue (avoid for first 24-48hrs).
Isos are analgesic, as not length­ening or shortening but stimul­ating blood flow (Ferendez, 2015). 4-5x40-60s
Progress to middle stage: minimal pain, AROM 75% normal

Middle Rehab (2-6 Weeks)

Isos warm up into isotonics
Heavy slow resistance
Progress to late: Pain permit­ting, close to full ROM, strength testing, confidence

Late Rehab (6+ Weeks)

Sport specific & cardio­vas­cular
Isokinetic and plyos
Resist­ance: 3x week w 24hrs rest and 48hrs within same muscle group, 2-4x8-12
Neurom­uscular control: balance and propri­oce­ption on rest days
PATS (hammies)

Muscles at Risk

Biarth­rodial muscles (greater contra­ction velocity and greater capacity to change length)
Muscles contra­cting eccent­rically
Muscles with higher % of Type II fibres (fast twitch)
Examples: gastroc, hamstring, quads, hip flexor, hip adductor, erector spinal, deltoid, rotator cuff