roald bahr

1

Muscle Injury Prevention

Prof. Roald Bahr MD PhDHead, Aspetar Sports Injury & Illness Prevention ProgrammeChair, Oslo Sports Trauma Research Center Chief Medical Officer & Department Chair, Olympiatoppen & Norwegian Olympic Training Center

1. Establishing the extent of the injury problem:

• Incidence• Severity

2. Establishing etiology and mechanisms of sports injuries

3. Introducing a preventive measure

4. Assessing its effectiveness by repeating step 1

Idea for prevention?

IBV; Eyjolfsson & Jonsson, 2000

Pilot data – eccentric strength training

1992 1993

Num

ber

of h

amst

rings

str

ains

0

1

2

3

4

5

6

7

8

IBV; Eyjolfsson & Jonsson, 2000

Pilot data – eccentric strength training

1992 1993 1994 1995 1996 1997 1998 1999 2000

Num

ber

of h

amst

rings

str

ains

0

1

2

3

4

5

6

7

8

Idea for prevention?

Test it!

2

The exercise prescription

Week

1

2

3

4

Sessions/week

1

2

3

3

Sets and Repetitions

2 x 5

2 x 6

3 x 6-8

3 x 8-10

5-10 3 3 x 12+10+8

10+ 1 3 x 12+10+8

Mjølsnes et al. Scand J Med Sci Sports, 14: 311-317, 2004

cons ext ecc flex isom flex 90 isom flex 60 isom flex 30

Knee

tor

que

(Nm

)

-10

-5

0

5

10

15

20

25

30 Nordic hamstring Hamstring curl

Eccentric strength training Delayed onset muscle soreness

1 2 3 4 5 6 7 8 9 10

DO

MS

(0

-10

)

0

1

2

3

4

5

6

7

8

9

10

Nordic hamstring Hamstring curl

The Iceland-Norway study- the OSTRC hamstring strain prevention program

Arnason et al. Scand J Med Sci Sports. 18:40-8, 2008

3-component program:

1 Warm-up stretchGoal: Stretch towards maximal ROM

2 Flexibility trainingGoal: Increase maximal ROM

3 Eccentric strength trainingGoal: Increase strength


Results – stretching

Stretching Control

Ham

strin

g in

jury

inci

denc

e (p

er 1

000

h)

0,0

0,1

0,2

0,3

0,4

0,5

0,6

0,7

2000 2001

3


Results – strength training

Total Match Training

Ham

strin

g in

jury

inci

denc

e (p

er 1

000

h)

0,0

0,5

1,0

1,5

2,0

2,5

3,0Training groupNo training

RR: 0.35p<0.001

Petersen et al. Am J Sports Med 2011 Aug 8 [Epub ahead of print]


Overall injury risk

Control Intervention

Stra

ins

per

100

play

er s

easo

ns (

%)

0

2

4

6

8

10

12

14

aRR=0.29 (95%CI 0.15-0.57)

Number neededto treat:

13


Stra

ins

per

100

play

er s

easo

ns (

%)

0

10

20

30

40

50


New injuries


Stra

ins

per

100

play

er s

easo

ns (

%)

0

2

4

6

8

10

12

14

aRR=0.41 (95%CI 0.18-0.93)


25

aRR=0.14 (95%CI 0.04-0.51)

Recurrent injuries


3

Take home message

If you enjoy risk taking, you should NOT include

Nordic Hamstrings in yourtraining program

”Intellectuals solve

problems; geniuses prevent them”

Albert Einstein(1879 – 1955)

4

The Oslo Sports Trauma Research Center has been established at

the Norwegian School of Sport Sciences through generous grants from the Royal Norwegian Ministry of Culture, the South-Eastern Norway Regional Health Authority, the International Olympic Committee, the Norwegian Olympic

Committee & Confederation of Sport, and Norsk Tipping AS