Muscle Injuries

result of intrinsic muscle injury

strain and tears

result of extrinsic muscle injury

contusion

cause of muscle strain/tear

excessive tensile forces

clinical presentation of muscle strain

bleeding, pain with active contraction, pain with passive stretching

why are muscle strains more common in hamstrings, quads, and gastroc

higher forces from working eccentrically, high proportion of fast twitch muscle fibers, high passive tension from crossing 2 joints

grading of muscle injuries

0-4 relating to severity and a-c relating to location

why are muscle injury locations indicated in the classification

it relates to the tissue type which is important in prognosis and healing time line

function of ultrasound in muscle injuries

helps diagnosis (severity), track change in injury with active/passive movement, see muscle recruitment

first step of acute muscle strain management

minimize pain and edema

acute muscle strain management

neuromuscular re-education, prevent excessive scar formation, ice, compression, mobilization within pain limits, massage peripheral to lesion

relationship between speed of movement and load on muscle

increase speed → stiffer tendon → faster load to muscle

intramuscular vs intermuscular hematoma

intermuscular is more visible but less painful because there is less pressure

management of muscle contusion

assess for compartment syndrome, compression, ice, place in pain-free stretched position, protective equipment

potential consequence of muscle contusion

myositis ossificans from the hematoma calcifying leading to bone tissue deposited within the muscle

risk factors for myositis ossificans

heat, massage, forced stretching

grade I strain

minimal tearing, feels like a pulled/cramping muscle

grade II strain

partial tearing, stinging/burning sensation

grade III strain

complete tear that may result in a lump where the muscle has torn

sprinter vs dancer hamstring injury

dancers injuries look better but take longer to recover because they occur more in the tendon

hamstring lengthening exercises effect on injury rehab

reduces time to return to sport and reinjury, safe to do early in the program

effects of pain free vs pain threshold rehab

pain threshold exercises did not accelerate return to play but also did not cause any adverse effects, led to greater recovery of isometric knee flexor strength

objective measures good at diagnosing hamstring strains

knee flexor strength, hamstring length, knee extension deficit

goals of phase I of hamstring rehab

minimize pain and swelling, preserve hamstring length, restore gait mechanics

treatment included in phase I of hamstring rehab

ice in lengthened position 4-5x per day, compression until swelling stabilizes, manuals for swelling control

exercises in early stages of hamstring rehab

bilateral bridge, hip 45 degree hip extension, hip extension on cable, bilateral eccentric slider

exercises in middle stages of hamstring rehab

unilateral bridge, nordic hamstring, RDL

risk factors for hamstring injuries

high speed running/jumping; older than 23 years; previous ACL tear, knee ligament sprain, calf strain

causes of chronic muscle strains

weak muscle from scar tissue, need the whole muscle suddenly, improper rehab

how to determine central activation ratio (CAR)

MVIC over burst augmented (estim) force