Hamstring

Question 1

How hamstring can withstand injury

Answer 1

1. strong
2. eccentric strength
3. long lengths
4. speed

Question 2

Ticket muscles for hamstring injury

Answer 2

Hamstrings and GMa

Question 3

Risk factors for hamstring injury

Answer 3

1. previous HS injury
2. Inadequate rehab from previous HS injury
3. Older age (over 23)
4. Reduced HS strength
5. Sprinting sport participation

Question 4

Pathogenesis

Answer 4

1. Type 1 - sprinting
2. Type 2 - stretching
3. Recurrent HS injury

Question 5

Why do hamis injuries occur at MTJ (musculotendinous junction)?

Answer 5

¬ Bc the long proximal tendon of hamis projects far into the muscle bellies, forming elongated MTJs, almost any area along the course of the muscle can be injured
¬ Proximal hamis strain affect proximal MTJ, whilst central hamis strains affect the intramuscular MTJ, causing intramuscular tears

Question 6

Pathophysiology

Answer 6

G1 - small disruption, minor swelling and bruising, no loss strength and function
G2 - partial tears
G3 - complete rupture

Question 7

Physical features

Answer 7

Bruising, palpation (HS, proximal HS tendon and GMa), isometric muscle testing, HS strain and stretch test, single leg raise and hip quad

Question 8

Triage

Answer 8

complete HS rupture

Question 9

initial management

Answer 9

1. POLICE - remain active as possible abiding to 4/10 rule
2. compression and elevation
3. NSAIDS - deleterious to healing
4. Isometric loading
5. HS stretching
6. Massage

Question 10

Rehab

Answer 10

1. Restore HS strength
2. Improving functional strength
3. Functional exercise

Question 11

Phases of restoring HS strength

Answer 11

Phase 1
→	Resisted knee flexion
→	45 degree hamstring bridge
→	45 degree hip extension
Phase 2
→	Resisted knee flexion alternated with 45 degree hamis bridge
→	Hamis eccentrics
→	Single leg RDL (Romanian Dead Lift)
Phase 3
→	Hamis eccentrics alternated with 45 degree hip extension
→	Single leg RDL alternated with Nordic curls
→	Glut ham raise

Question 12

Why does the terminal swing phase in sprinting place the most stress on the hamstrings?

Answer 12

all muscles are at their peak muscle strain, peak muscle force and largest eccentric work. LHBF receives the greatest force

Question 13

Length-tension relationship definition

Answer 13

phenomenon whereby a muscle or single muscle fibre displays diff levels of max isometric force production depending on the length at which it’s being tested

Question 14

Peak torque and length-tension relationship

Answer 14

• Mid-length because there is optimal actin and myosin cross bridge overlap. Inner and outer there is less cross bridge formation so reduced capacity to produce force
• Length tension relationship not fixed can shift
• eccentric training shifts the graph up and to the R, muscle gets stronger at longer lengths
• 90 is peak force angle as where can produce greatest force

Question 15

Characteristics of complete HS rupture

Answer 15

o Sudden onset in the same manner as gr II hamis strain, may hear a ‘pop’
o Severe pain followed by a reduction of pain
o Potential palpable deformity in proximal thigh
o Weakness with isometric testing
o Isometric tests severely painful