Muscle Strain Injuries

Question 1

How do muscle strain injuries occur and where do they usually occur

Answer 1

overstretching of the muscle fibres during eccentric contraction

usually close to the muscle-tendon junction

Question 2

explain the grading system for muscle strain injuries

Answer 2

1 =  some fibres involved 
2= significant number of fibres involved 
3 =  complete tear

Question 3

what is the most common type of muscle strain injury

Answer 3

hamstring specifically biceps femoris

Question 4

what is the mechanism of injury of a hamstring strain

Answer 4

occurs during terminal swing phase

here the hamstrings are undergoing eccentric contraction

therefore the muscles are under the greatest stretch at this point (bc knee extension and hip flexion are happening simultaneously)

Question 5

give some intrinsic risk factors for suffering a hamstring strain

Answer 5

previous hamstring injury 
inbalance between hamstrings and quads 
lack of flexibility 
older age 
muscle weakness

Question 6

give some extrinsic risk factors for suffering a hamstring strain

Answer 6

inadequate warm up
fatigue
dehydration

Question 7

give some signs and symptoms of hamstring strain injuries

Answer 7

occurs during sprinting 
hear a pop
have to stop sprinting, may fall to the ground 
stiffness or tightness 
discolouration/bruising 
swelling

Question 8

describe how to perform a puranen-orava test and what would be found if the patient had suffered an injury

Answer 8

patient stands with hip flexed to 90 and knee fully extended

if pain is made worse by this it is suggestive of injury

Question 9

describe how to perform the bent knee stretch test and what would be found if the patient had suffered an injury

Answer 9

patient laid on the bed with knee and hip maximally flexed
the knee is then passively extended

pain when the knee is extended indicates injury

Question 10

how is the hamstring to quad ratio usually measured and how does one of these work

Answer 10

isokinetic dynamometer test

speed of flexion or extension which is allowed is fixed
measures the torque which the patient is able to generate

Question 11

what is the difference between the conventional and the functional hamstring to quads ratio

Answer 11

conventional = concentric contraction of both

functional = concentric quads contraction and eccentric hamstring contraction

Question 12

what values should be obtained for the hamstring to quad ratio

Answer 12

at least 60%, ideally 75%

Question 13

what is the treatment for a complete hamstring tear

Answer 13

surgery may be needed to re-attach both ends of the muscle to allow them to then heal

following surgery the leg will generally be held in a brace to limit stress on the surgical site

Question 14

how long is the average recovery time following surgery for a complete hamstring tear

Answer 14

6-10 months

Question 15

why are eccentric exercises preffered to concentric exercises when aiming to prevent recurrence of hamstring injuries

Answer 15

because they have been shown to provide greater gains in strength

Question 16

when would a proximal hamstring tear be considered for surgery

Answer 16

if 2 tendons are involved and there’s >2cm retracton

or if all 3 tendons are involved

Question 17

Give examples of exercises which can be performed as part of a rehab programme from hamstring injury

Answer 17

Hamstring and glute stretching

Supine bent knee walk out exercise

Supine single limb chair bridge exercise

Single limb balance windmill touches with Dumbbells