WEEK 8: THIGH -> hamstring and anterior thigh pain

Question 1

mechanism of hamstring injury

Answer 1

Acute injury -
- Sudden onset with moderate to severe pain

Type 1 -
- Long head biceps femoris at proximal musculotendinous junction
- Sprinting -> during terminal swing the hamstring muscles contract eccentrically to decelerate the lower leg prior to foot strike

Type 2 -
- Semitendinosus
- End of range hip flexion and knee extension with high power activities
Kicking, dancing, hurdling

Question 2

pathology of hamstring injury
- grades
- stages of healing

Answer 2

Grade 1 -
- Minimal structural disruption and rapid return to normal function

Grade 2 -
- Partial rupture (approximately 50% fib torn) pain and some loss of function

Grade 3 -
- More than 50% fibres torn to complete tissue rupture with muscular retraction and functional disability

Inflammation:
- Up to 3-7 days from injury
- Disruption of the muscle then necrosis of myofibrils by haematoma formation and inflammatory cells

Proliferation:
- 4-21 days from injury
- Phagocytosis of necrotic tissue, regeneration of myofibrils, production of scar tissue, vascular neoformation and nerve growth

Remodelling:
- 14 days to 14 weeks
- Maturation of regenerated myofibril and reorganisation of muscle functional capacity

Question 3

risk factors of hamstring injury:
- modifiable
- non-modifiable

Answer 3

non-modifiable:
- History of previous hamstring injury:
> RR=2.86, 95%CI=1.83 to 4.47, p<0.001
- History of previous injury in last 12 months:
> AOR=4.3, 95%CI=1.66 to 11.15, p=0.003
- History of other lower limb injuries -> osteitis pubic / knee injury / ACL reconstruction on same side
- Older age
- Ethnicity -> aboriginal descent, African descent, new Zealand Māori / pacific islander

modifiable:
Ankle dorsiflexion:
- < 12cm in community players
- <10cm in elite AFL players
High flexor tightness / reduced ROM
- Shortness of the quadricep muscles and iliopsoas muscles increases risk of hamstring injury
Stronger quadriceps muscles compared to hamstring muscles -> concentric contractions

Question 4

objective exam for hamstring injury

Answer 4

• Observation
  
  • Functional
  • AROM
    > L x AROM, hip E, knee flexion
    > ankle DF
    > hip flexor length
  • Muscle strength
    > knee flexion at 90 degrees E and 30 degrees E
    > knee extension and hip flexion
    > single leg hamstring bridge
  • Motor control -> lumbopelvic stability
  • Nerve tests -> slump
  • Special tests -> L x spine / SIJ
    Palpation