Categorization
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 |
|
|
MOI
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
MOI? |
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
Observations |
Swelling, bruising, or redness |
Palpation |
Painful to palpate, may feel tear |
AROM/PROM |
Pain with AROM but not PROM indicative of muscle injury |
Strength |
Decrease w movement (Grades II-III) |
Functional Tests |
Pick up mug, brush teeth, STS, Squats |
|
|
Early Rehab (0-2 Weeks)
PEACE & LOVE |
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 |
|
