Hamstring injury: Knowns and unknowns

1. Hamstring injury: Knowns and unknowns
Tony Shield
School of Exercise & Nutrition Sciences, QUT

2. What do we know?
• Rates (some sports)
• Mechanisms
• Sites
• Risk factor ID ≠ prediction
• We can’t all agree!

3. Theory v evidence

4. Petersen et al 2011 & van der Horst et al 2015
Evidence is often not enough…
Effective* but unpalatable
Combined results
Nordic groups: 753 players  25 injuries
Control groups: 768 players  77 injuries
67.5% reduction
Unlikely the only exercise that works

5.  BFLH fascicle length?
 Eccentric strength
Collagen isoforms?
ECM adaptations?
We often ignore alternative explanations…

6. We love our surrogate outcome measures
Real outcomes
• Performance
• Injury rates
Surrogate outcomes
• Strength
• Fascicle lengths
• Kinematics
• Endurance…

7. We have evidence – belief Mismatches

9. Sherry & Best 2004 JOSPT 34:116-125
 Hamstring Injury
Recurrence
Trunk stability
Agility
+
 Hamstring Injury
Recurrence
Strength
Stretching
+
Evidence for trunk exercises 
PATS
STST
Evidence for ‘stability’
We too often kid ourselves…

10. Core Stability?
Ambiguous & pretentious
Lumbopelvic kinematics

11. Is there evidence for isometrics?

12. Eccentrics Isometrics

13. Shield & Murphy (2018) Sports Perf Sci Reports

14. What don’t we know enough about?
• Risk factors
– How they interact
• Muscle-tendon junctions
• Role of high speed
running in prevention
• Optimal rehabilitation

15. Schuermans et al Gait & Posture 2017, 57: 270-277
Do ‘bad’ LBP kinematics  injury?
Evidence currently scant
(based on 4 injuries!)

16. How might we fix ‘bad’ LBP kinematics?

17. Muscle-tendon junctions…
Injury prone
Adaptable
Adaptations likely depend on
rate of force development

18. It’s likely complicated…