The impact of head impacts in sports Jason P. Mihalik, PhD, CAT(C), - - PowerPoint PPT Presentation

The impact of head impacts in sports

Jason P. Mihalik, PhD, CAT(C), ATC

Associate Professor, Department of Exercise and Sport Science Co-Director, Matthew Gfeller Sport-Related TBI Research Center @jmihalik79

Disclosures

Chief Science Officer

“I was wearing a helmet designed to prevent concussions, so I can’t have a concussion”

Helmet testing in 1912

Concussion: A multifaceted condition

Traumatic Brain Injury

Cognition Concussion history Postural stability Mechanism

• f

injury Physical exam Symptomatology Knowledge, Attitudes, Behaviors Treatment

Head Impact Monitoring Systems

Impact Data

Neurosurgery, 2007

Mechanism

• f injury

Case # Player Position* Linear Magnitude (g) Rotational acceleration (rad/s2) Impact Location ΔSymptom Scores† ΔSOT Composite‡ ΔANAM Composite‡ 1 OL 60.31 5419.18 Front 2

• 4.88

N/A 2 RB 60.51 163.35 Top 12

• 19.15
• 0.20

3 LB 63.84 5923.27 Front 8

• 15.68
• 0.35

4 WR 66.36 5573.42 Front 23 3.85 N/A 5 RB 77.68 3637.48 Top 8

• 29.18

0.22 6 DB 84.07 5299.57 Front 7

• 2.25
• 0.26

7 DB 85.10 3274.05 Top 4 4.11 0.49 8 LB 94.20 7665.10 Front No baseline data available 9 DL 99.74 8994.40 Front 27

• 4.07

0.14 10 OL 100.36 1085.26 Top

• 2.00

1.01 11§3 LB 102.39 6837.62 Right 30

• 60.01
• 1.56

12 OL 107.07 2811.45 Top 9

• 20.57
• 0.76

13§5 RB 108.02 6711.00 Front 2

• 17.79

N/A 14 DB 109.88 6632.77 Top 16 2.70

• 0.06

15§14 DB 115.50 2303.63 Top 2

• 1.49

N/A 16 DL 119.23 7974.22 Right 12 2.89 0.12 17 LB 157.50 1020.00 Front 14 0.71 0.42 18 WR 168.71 15397.07 Back 13 7.33 0.79 19 RB 173.22 4762.74 Top 32 8.08 N/A

Special teams & closing distance

• 3x risk of severe impacts during special

teams plays vs. offense/defense

• Over 4.5x risk of severe impacts during

long closing distance (>10yds) vs. short closing distance (<10yds)

Ocwieja, Mihalik, ABME 2012

NFL’s 2011 kick-off rule change

33% reduction in the number of returned kickoffs

Table 2. Regular Season Game Kickoff Statistics in 2011; 3-year Comparison

Result of Kickoff Year Total Returns Touchbacks Fair Catches Kick Out of Bounds Short Free or Onside Kicks Opponent Received Total Kickoffs 2008 2114 371 7 36 47 1 2576 2009 2004 401 12 30 36 1 2484 2010 2034 416 7 39 43 2539 2011 1375 1120 1 26 50 2572 Average 2008-2010 2050.7 396 8.7 35 42 0.7 2533

Table 3. Significant Injuries As a Function of Kickoff Plays 2011 Regular Season; 3-year Comparison

Regular Season Games Year Concussions Neck/Spine Fractures ACL Sprain All Injuries 2008 (N=2576) 26 (1.0%) 12 (0.5%) 10 (0.4%) 3 (0.1%) 152 (5.9%) 2009 (N=2484) 25 (1.0%) 7 (0.3%) 6 (0.2%) 2 (0.1%) 147 (5.9%) 2010 (N=2539) 28 (1.1%) 7 (0.3%) 11 (0.4%) 8 (0.3%) 135 (5.3%) 2011 (N=2572) 15 (0.6%) 8 (0.3%) 8 (0.3%) 7 (0.3%) 136 (5.3%) Average 2008-2010 (N=2533) 26.3 (1.0%) 8.7 (0.3%) 9.0 (0.4%) 4.3 (0.2%) 144.7 (5.7%)

NFL’s 2011 kick-off rule change

42% reduction in the number of concussions

High school football rules?

Table 1. HS RIO™, Original Sample Competition Football Injuries by Punt, Kickoff and General Play, 2005/06-2011/12 School Years.

% of Competition Injuries that were Concussions Punt Kickoff General Play Year 2005/06 23.9% 21.1% 10.8% 2006/07 19.6% 43.0% 11.2% 2007/08 19.0% 31.5% 12.3% 2008/09 18.1% 34.4% 14.0% 2009/10 14.6% 39.8% 18.9% 2010/11 37.0% 61.4% 24.3% 2011/12 35.0% 48.3% 20.8% Overall 24.0% 42.4% 16.0%

Concussion: A multifaceted condition

Traumatic Brain Injury

Cognition Concussion history Postural stability Mechanism

• f

injury Physical exam Symptomatology Knowledge, Attitudes, Behaviors Treatment Head Impact Indicators

Head impact indicators

Med Sci Sport Exer, 2010

Thresholds & positive predictive values

Threshold Sensitivity (95% CI) Specificity (95% CI) Positive Predictive Value Resultant Linear Head Acceleration 20 g 100% 56% 0.01% 50 g 95.8% 90.4% 0.1% 75 g 75.0% 97.0% 0.2% 100 g 45.8% 99.0% 0.4%

What does this mean for the clinician?

Threshold Practice Game PV+ (n) Resultant Linear Head Acceleration 50 g 358 620 0.1% (1 inj) 75 g 73 166 0.2% (<1 inj) 100 g 24 79 0.4% (<1 inj) Number of impacts exceeding various thresholds in one complete high school football season: 16,402 total impacts collected (8791 in practice; 7611 in games)

• There is NO reliable concussion threshold
• We all want to better protect our athletes
• Must take many things into account ….
• 1. Cost
• 2. Risks
• 3. Does it add clinical value?
• Research will continue to benefit from monitoring

technologies

The bottom line

Matthew Gfeller Center

Jason P. Mihalik, PhD, CAT(C), ATC

Matthew Gfeller Sport-Related TBI Research Center jmihalik@email.unc.edu 919.962.2573 http://tbicenter.unc.edu @jmihalik79