Kori kryotherapy athletic recovery center

Week5SportInjuryPreventionPart2.pdf
Sports Injury Prevention Part 2: Strength, or length? Part 1 was published in Modern Athlete and Coach January 2015 Dr Mark Brown

Mark Brown B.App.Sc(Phty); MHSc(Sports Physio); MBA; FASMF; FAIM Mark Brown is an Australian Physiotherapy Association (APA) titled Sport Physiotherapist with over 30 years’ experience in sports medicine. Currently he holds positions as the Executive Officer o f Sports Medicine Australia’s Queensland Branch, adjunct Associate Professor in the Griffith University Centre of Musculoskeletal Research and as a Member of the Oceania National Olympic Committees Medical Commission. He is a Fellow o f both the Australian Sports Medicine Federation and the Australian Institute o f Management and was the Director of Physiotherapy for the Sydney 2000 Olympic and Paralympic Games. Mark's main clinical and research interest areas relate primarily to improving safety in sport and physical activity and he has published and presented internationally in particular on: • improving the prevention and management o f medical emergencies in sport • the use of neuromuscular training programs for sports injury prevention and performance enhancement • the use of taping techniques for the prevention and treatment o f musculoskeletal conditions.

In the previous article I outlined some of the main components of an evidence informed approach to sports injury prevention, especially including the proven effectiveness of multi- component neuromuscular training programs to both reduce the number and severity of lower limb injuries in athletes, and also improve sporting performance. Neuromuscular training programs aim to improve strength and control during sports specific movements and this article will briefly examine the sometimes controversial topic of the role of flexibility training as a component of sports injury prevention programs, and whether muscle length or muscle strength are most associated with reduced sports related injuries.

Until relatively recent times the conventional wisdom amongst athletes, coaches and health professionals was that stretching exercises to increase muscle length and joint range of motion were an essential component of injury prevention programs for athletes. But a number of research studies conducted in the late 1990’s and early 2000’s produced results that caused a rethink of this concept. In particular a landmark large scale study conducted in Australia by Pope et al (1998) found there was no meaningful difference in the number of lower limb injuries in army recruits who used static stretching exercises in their warm up program compared to those whose warm up program did not include stretching.

Subseguent studies by other researchers produced similar conclusions with respect to injury prevention, while others also found that stretching before or after exercise did not reduce delayed onset muscle soreness (DOMS), or other types of exercise related pain, or measures of recovery. Around the same time other researchers found that stretching, especially static stretching, temporarily decreases muscle power which is obviously not a desirable outcome for optimal performance in most sports, especially those requiring explosive power.

But other studies looking at risk factors for sports injuries have shown that reduced flexibility or range of motion (ROM) are

associated with some types of sports injuries. For example, reduced hamstring extensibility was found to be associated with an increased predisposition to hamstring strains, and reduced ankle dorsiflexion range of motion is a risk factor for ankle injuries. But even these findings are complicated by yet other studies that show that an even greater risk factor for injury for most muscle injuries is not muscle length, but muscle strength. For example, for thigh adductor muscle strains (groin strains) adductor length or extensibility has been found to not be a risk factor for injury, however reduced adductor strength as measured on the adductor squeeze test is. Similarly, the biggest risk factor for a hamstring strain injury according to current evidence is reduced hamstring eccentric strength rather than decreased hamstring extensibility, and eccentric strengthening of the hamstring muscles in the eccentric hamstring lower exercise (often commonly referred to as “ Nordic hamstrings” ) has been found to be protective for hamstring strains.

This particular exercise has become an im portant component of many sports injury prevention programs including the FIFA 11 + injury prevention program. While this particular program is mostly orientated to injury prevention in Football many of the exercises can be readily adapted by athletics coaches and is worth a look at as the videos and other resources on the FIFA website clearly outline the exercises (http://f-m arc. com /11plus/hom e/). Currently researchers are attempting to establish minimum benchmark strength measures or strength ratios for exercises such as the Nordic hamstring curl which eventually will assist coaches and the athlete’s attending health professionals when screening athletes for injury risk factors, but at present normative data is limited.

Other research studies support the notion that strength is more im portant than length for injury prevention. Recently Lauersen et al published an article in the British Journal of Sports Medicine in 2014 that examined the effectiveness of exercise interventions to prevent sports injuries. The authors

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http://f-marc
conducted a systematic review and meta-analysis of 25 randomised controlled clinical trials (26,610 total participants) to determine which physical activity interventions were most effective for sports injury prevention. The analysis determined that stretching did not reduce injuries, but strengthening and proprioceptive exercises did. Strength training was the most effective intervention and reduced sports injuries to less than one third (Relative risk ratio 0.315). Proprioceptive training was also found to be effective though less so than strength training (Relative risk ratio 0.550).

So based on some of the research findings it’s tempting to say that on the whole muscle strength is more im portant for injury prevention than muscle length. However, this view is overly sim plistic and ignores the fact that in some sports a certain degree of flexibility is necessary to effectively execute some of the required techniques, especially sports such as gymnastics, dance, and some martial arts disciplines but also in some track and field disciplines so a “ one size fits all” approach with regards to what sort of flexibility training is required is not appropriate. It also doesn’t take into consideration that stretching programs don’t just alter muscle length, they also have an effect on tendon elasticity which is also relevant to sports performance. It is often forgotten that the muscle should be more accurately described as a muscle tendon unit with the contractile component of the MT unit (the muscle fibres) applying a force to the boney attachments via the non-contractile components (the tendon and fascial tissue) so what sort of exercise interventions most effect tendon and muscle tissue also needs to be considered.

So how do we put all of this together? At the moment according to current research evidence it’s not a matter of “ stretching: yes or no?” but rather that stretching can be a useful part of programs if the type and tim ing of stretching programs is contextualised to the sport, and also customised to the individual differences in morphology, risk factors as identified in the screening process, and the sporting tasks required for each athlete. But, some of the factors that could be taken into consideration include:

• On the basis that the muscle tendon (MT) unit needs to be compliant enough to store and release energy effectively in the Stretch Shortening Cycle (SSC) this would suggest that more compliance in the MT unit would decrease muscle and tendon injury because the load on these tissues would be reduced. However, static and dynamic stretching immediately before activity have been found to be counter-productive to force generation, possibly through overstimulation of the stretch receptors.

• According to Kubo et al 2000 moderate or low SSC demand sports like running or cycling do not benefit from making the MT unit more compliant.

• However, sports with jumping or bouncing activities with a high intensity of SSCs require a MTU compliant enough to store and release the high amount of elastic energy required in such sports.

• Dynamic stretching produces no or little effect on muscle length but has a significant influence on tendon stiffness, which in turn increases storage and release of elastic energy in tendons which is useful in high SSC sports like jumping. But dynamic stretching is not the best technique to increase range. Kubo et al (2001) found that dynamic stretching does decrease tendon stiffness using a protocol of 2 sessions of dynamic stretching per day for 8 weeks. However, this benefit was soon lost if the stretching exercises were not maintained.

• Witvrouw et al (2007) compared dynamic stretching and static stretching and concluded that static stretching is a better technique for increasing ROM and dynamic stretching is better for increasing tendon elasticity. In their view if ROM alone is the goal or is critical to success in a particular sport or activity then static stretching as part of an overall program is indicated, though not as part of the warm up due to the temporary muscle force reduction.

• To increase muscle range of motion a large volume of static stretching is required. Marshall et al (2011) demonstrated a 20.9% increase in hamstring extensibility, but the program involved 4 different hamstring stretches, each performed 5 times a week for 4 weeks, (including 1 supervised session per week), with each stretching exercise held for 30 seconds with 3 repetitions of each.

• Konrad and Tilp (2014) concluded that static stretching did not produce a change in muscle length or structure, however people who stretch often increase range of motion due to an increased tolerance to stretch, and /or increased pain tolerance.

• Warm-up before sport also increases the visco-elasticity of the muscle tendon unit and therefore may be more appropriate than stretching immediately before sport. But as individual variation do occur different approaches to stretching and warm up for each athlete should be tested outside of competition using sports specific measures of performance.

So which stretching technique you would use and when depends on sports specific goals. Also, you need to do a lot of stretching (which costs a lot of time) to get measurable results. While that is getting complicated enough, none of the above takes into consideration the possible additional confounding variables associated with variations in joint hypo / hyper­ mobility, or the effects of age, metabolic and genetic factors on tendon tissue. But, overall for athletes with reduced flexibility there is still an argument in favour of incorporating flexibility training into their programs, but probably not immediately before sporting performance. The type of stretching and what areas should be focused on will depend on the findings by the Physiotherapist in a comprehensive musculoskeletal screening in conjunction with the coaches identification of each athlete’s training goals and sports specific role.

What is clearer is that increasing muscular power and control are important and effective in reducing injury and increasing

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performance, but gaining strength must as always take into consideration careful monitoring of the athlete’s total training load.

References:

Arnason A, Andersen T, Holme I, Engebretsen L and Bahr R. Prevention of hamstring strains in elite soccer: an intervention study. Scandinavian Journal of Medicine and Science in Sports, 2007

Konrad, A. and Tilp, M. (2014) Increased range of motion after static stretching is not due to changes in muscle and tendon structures. Clin. Biomech. 2014; 29(6):636-42.

Kubo K., Kanehisa H., Kawakami Y. and Fukunaga T. Effects of repeated muscle contractions on the tendon structures in humans. Eur. J Appl. Physiol. 2 0 0 1 ,8 4 ,1 6 2 -1 6 6 .

Kubo K., Kanehisa H., Kawakami Y. and Fukunaga T Influence of static stretching on viscoelastic properties of human tendon structures in vivo J App Physiol. 2001 90 (2), 520-527

Jamtvedt G, Herbert RD, Flottorp S, et al. A pragmatic randomised trial of stretching before and after physical activity to prevent injury and soreness. Br J Sports Med 2010;44:1002-9.

Lauersen JB, Bertelsen DM, Andersen LB. The effectiveness of exercise interventions to prevent sports injuries: a systematic review and meta-analysis of randomised controlled trials. Br J Sports Med 2014:48:871-7.

Marshall, R, Cashman A, Cheema, B. A randomized controlled trial for the effect of passive stretching on measures of hamstring extensibility, passive stiffness, strength, and stretch tolerance. J Sc. Med. Sp. 2011 14 (6) 535-540

Pope R, Herbert R, Kirwan J. Effects of ankle dorsiflexion range and pre-exercise calf muscle stretching on injury risk in Army recruits. Aust J Physiother 1998;44:65-72.

Pope RP, Herbert RD, Kirwan JD, et al. A randomized trial of preexercise stretching for prevention of lower-limb injury. Med Sci Sports Exerc 2000;32:271-7.

Witvrouw E, Mahieu N, Roosen P and McNair P. The role of stretching in tendon injuries Br J Sports Med. 2007 Apr; 41 (4): 224-226.

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Week3SportAndRecInjuriesByAge.pdf
Journal of Athletic Training 2014;49(6):780–785 doi: 10.4085/1062-6050-49.3.41 � by the National Athletic Trainers’ Association, Inc www.natajournals.org

original research

Child Development and Pediatric Sport and Recreational Injuries by Age

David C. Schwebel, PhD*; Carl M. Brezausek, MS†

*Department of Psychology, University of Alabama at Birmingham; †Center for Educational Accountability, University of Alabama at Birmingham

Context: In 2010, 8.6 million children were treated for unintentional injuries in American emergency departments. Child engagement in sports and recreation offers many health benefits but also exposure to injury risks. In this analysis, we consider possible developmental risk factors in a review of age, sex, and incidence of 39 sport and recreational injuries.

Objective: To assess (1) how the incidence of 39 sport and recreational injuries changed through each year of child and adolescent development, ages 1 to 18 years, and (2) sex differences.

Design: Descriptive epidemiology study. Setting: Emergency department visits across the United

States, as reported in the 2001–2008 National Electronic Injury Surveillance System database.

Patients or Other Participants: Data represent population- wide emergency department visits in the United States.

Main Outcome Measure(s): Pediatric sport- and recrea- tion-related injuries requiring treatment in hospital emergency departments.

Results: Almost 37 pediatric sport or recreational injuries are treated hourly in the United States. The incidence of sport- and recreation-related injuries peaks at widely different ages. Team-sport injuries tend to peak in the middle teen years,

playground injuries peak in the early elementary ages and then drop off slowly, and bicycling injuries peak in the preteen years but are a common cause of injury throughout childhood and adolescence. Bowling injuries peaked at the earliest age (4 years), and injuries linked to camping and personal watercraft peaked at the oldest age (18 years). The 5 most common causes of sport and recreational injuries across development, in order, were basketball, football, bicycling, playgrounds, and soccer. Sex disparities were common in the incidence of pediatric sport and recreational injuries.

Conclusions: Both biological and sociocultural factors likely influence the developmental aspects of pediatric sport and recreational injury risk. Biologically, changes in perception, cognition, and motor control might influence injury risk. Socioculturally, decisions must be made about which sport and recreational activities to engage in and how much risk taking occurs while engaging in those activities. Understanding the developmental aspects of injury data trends allows prevention- ists to target education at specific groups.

Key Words: athletes, youth, adolescents, athletic injuries, safety

Key Points

� Pediatric sport and recreational injuries are a significant public health concern in the United States. � The injury risk varies across child development for particular types of sport and recreational injuries. � Sex disparities were common in the incidence of pediatric sport and recreational injuries.

T he magnitude of fatal and nonfatal, unintentional, pediatric injuries represents an increasingly recog- nized public health problem in the United States and

around the world. Statistics from the Centers for Disease Control and Prevention indicate that 7712 US children died of unintentional injuries in 2009, or more than 21 children per day.1 Furthermore, more than 8.6 million children were treated for injuries in emergency departments (EDs) in 2010, representing 23 596 children treated per day, 983 per hour, and 16 per minute.1 Cost estimates resulting from injuries to American children, age 0 to 14 years, in 2000, exceeded $50 billion.2

Traditionally, injury researchers use 5-year age spans (eg, ages 0–4, 5–9, 10–14) to examine injury incidence during childhood. However, such a broad analysis of age groups lacks the precision that might be needed to understand fully how child and adolescent development interacts with the process of injury events and, subsequently, to design age-

appropriate injury-prevention strategies. Agran et al3 illus- trated this problem using data from the 1997 California Office of Statewide Health Planning and Development database. Analyzing injury hospitalization and death data, they showed an elevated poisoning risk among 1-year-olds (rate¼83 per 100 000) that was not well represented by the 0 to 4-year age range and that was far higher than the rate among 4-year-olds (rate¼14 per 100 000).3 This pattern was attributed to 1-year-olds being newly mobile and develop- mentally prone to explore, discover, and ingest potentially poisonous household items when unsupervised. By age 4, children may have developed the cognitive skills to avoid potentially poisonous household items.

Our analysis was conducted using data from the National Electronic Injury Surveillance System (NEISS),4 a database of injuries treated at hospital EDs across the United States. We considered all sport and recreational injuries reported during an 8-year time span (2001–2008) among children

780 Volume 49 � Number 6 � December 2014

ages 1 to 18 years. Our analysis was descriptive and focused on changes in injury incidence through child and adolescent development. Sex differences were considered as a secondary topic of interest.

METHODS

Data Source

Data for this study were taken from the 2001–2008 NEISS data sets, which are collected by the United States Consumer Product Safety Commission and the National Center for Injury Prevention and Control from a sample of hospital EDs across the United States. Specifically, the NEISS data were collected from about 100 hospitals, ranging from small to large, and including children’s hospitals. Patients treated at the sampled hospitals are representative of national injury patterns involving con- sumer products.4,5 Data are collected daily, 365 d/y, by hospital staff, using a standardized coding manual. Only initial hospital visits by patients are included in the data set. As detailed elsewhere,4,5 numerous safeguards flag and correct invalid coding or data entries. Secondary data analysis was approved by the institutional review board at the University of Alabama at Birmingham.

To adjust for selective sampling, the NEISS data set assigns sample weights to data points, so the data set estimates annual, population-based ED visits nationwide. Because we analyzed data across 8 years of the survey, sample weights were divided by 8 for analytic purposes, preserving the pattern of estimated, annual ED visits nationwide for our analyses. Therefore, frequencies report- ed in this article use sample weights and represent the number of annual ED visits by the US population during the 8-year period of 2001–2008.4

Variables

Patient age and sex were culled from medical records. Injury data from all sport- and recreation-related injuries in the NEISS data set incurred by children ages 1 to 18 years were included in the analysis. We omitted injuries to infants younger than 12 months because such infants are typically nonmobile, and injuries typically result from supervisor behavior and decisions rather than child behavior or decisions. We were interested in pediatric injuries only and, therefore, omitted injuries to individuals older than 18 years. Injury cases were classified into mutually exclusive categories of sport or recreational activities based on a combination of the consumer products involved (eg, scooter, skateboard, snow skis) and the medical description of the incident.

Analytic Plan

Our data analysis was descriptive. We first prepared a descriptive table displaying injuries across the 39 sport and recreation activities and the 18 years of age. Next, we examined the 5 most common causes of sport and recreational injuries for each year of age development. Last, we assessed the percentage of boys’ and girls’ injuries for each of the 39 sport and recreational injury types.

RESULTS

During the years 2001–2008, an estimated 2 566 178 children, ages 1 to 18 years, were seen in US EDs for sport or recreation injuries. That divides into about 320 722 injuries per year or about 37 pediatric sport and recreational injuries treated per hour in the United States.

The estimated national annual injuries by sport and recreational activity and by age are displayed in Table 1. The table is organized by frequency of injury, with the most

Figure. Trajectory in the number of injuries treated in emergency departments, by age, for the 5 leading causes of sport and recreational injuries to children in the United States, 2001–2008.

Journal of Athletic Training 781

frequent causes appearing first. Peak age of injury incidence for each activity is marked in bold. Bowling caused the most injuries to children at the youngest age (4 years), and camping and personal watercraft, the oldest (18 years). The years with the most peaks of sport and recreational activity injuries were the middle teenage years, with 6 activities peaking in frequency at age 14 years and 9 activities peaking at age 15 years.

Total injuries varied widely across years of age. In general, younger children incurred the fewest sport and recreational injuries, and injury counts increased steadily

into the early teen years, with the overall peak occurring at 14 years. The decline in the later teen years was modest until age 18 years, when the rate plummeted to a rate comparable with age 6 years. Total injuries also varied widely across sport and recreational activities. Billiards, camping, and personal watercraft use all resulted in fewer than 200 injuries per year nationally, whereas basketball, football (American style), and bicycling each caused more than 300 000 injuries.

The 5 leading sport- and recreation-related injury causes at each age of development are shown in Table 2. In

Table 1. Estimated Number of Annual Injuries in the United States by Sport or Recreational Activity and Age Extended on Next Page

Activitya

No. of Injuries by Age, y

1 2 3 4 5 6 7 8 9 10 11 12 13

Basketball 181 397 450 764 1396 2437 3504 5603 9812 16 077 24 988 33 817 42 611

Football 91 138 304 550 918 1919 4237 7509 12 757 19 374 27 298 36 953 42 543

Bicyclesb 2517 5270 8212 12 522 16 719 19 816 21 505 22 777 25 492 26 997 27 719 28 733 27 126

Playgroundsc 8051 12 246 14 585 18 990 27 561 28 279 25 254 20 216 16 777 13 606 9573 6346 3453

Soccer 93 127 248 347 974 1637 2661 4051 6561 9061 11 075 12 616 15 007

Baseball 419 803 1507 2075 2827 3548 5040 5937 8224 10 708 11 627 11 909 11 405

Skateboards 110 307 608 628 1037 1287 1864 2997 3515 5121 7415 11 400 13 351

Trampolines 1131 2790 4103 4569 5694 6492 6613 7513 7600 7390 7375 7040 6032

Exercised 1921 2585 2184 2212 2218 2068 2327 2400 2990 3333 3720 4622 5002

Gymnastics and cheerleading 360 462 745 691 1149 1673 1701 2721 3573 5076 4870 5905 6589

Lacrosse and rugbye 348 636 825 646 1039 1293 2149 3193 4579 6049 6365 5907 5888

Swimming 1240 1997 2866 3153 3905 4203 3923 3912 4319 4403 4347 4544 3822

All-terrain vehicles 411 541 608 889 1222 1459 1705 2022 2465 2819 3604 4182 5178

Scooters 509 1114 2187 2560 4047 4348 4379 5342 5872 5889 5943 4218 2886

Snow skiing 0 50 29 114 376 417 818 1144 1859 2564 3999 5699 7271

Combative 5 86 74 117 315 556 661 1206 1416 1486 1949 3999 4692

Softball 34 67 74 79 191 245 494 675 1709 2195 3495 4373 6049

Hockey 22 66 95 239 242 403 683 734 875 1710 2817 3924 5295

Mopeds and minibikesf 15 137 85 161 293 471 910 1080 1614 1830 2595 3288 3853

Roller skatingg 48 133 140 363 745 1536 2111 3308 4095 4929 4519 4014 2896

Volleyball 3 3 6 30 58 55 164 407 679 876 1574 2920 4046

Inline skating 16 9 43 74 346 685 1078 2210 3031 3853 3674 3478 2390

Horseback riding 46 295 319 350 489 491 564 1161 1305 1476 1849 2309 2368

Tobogganing and sleddingh 45 175 474 719 965 1190 1417 1586 1944 2138 2374 2151 1708

Fishing 236 423 484 771 820 936 929 1136 1225 1492 1650 1853 1682

Golf 183 612 847 1083 1213 1286 1508 1461 1105 1050 944 876 993

Track and field 1 1 0 3 17 8 82 102 188 329 781 1276 2074

Amusementi 423 662 893 808 1036 1122 983 968 1275 1279 965 1028 831

Ice skating 2 21 81 217 479 677 1309 1018 1323 1611 1388 1303 1402

Go-carts 61 188 236 188 287 407 695 549 711 957 1040 1242 1117

Water skiingj 0 20 28 37 49 96 114 224 338 413 647 697 971

Racquet sports 21 86 71 72 115 171 223 362 364 380 464 668 713

Bowling 43 358 511 722 557 436 436 344 210 271 278 183 279

Snowmobiles 29 28 45 46 31 33 60 92 112 55 125 103 276

Nonpowder guns 31 67 121 25 16 37 69 6 140 187 173 242 213

Billiards 74 94 81 152 98 63 115 53 119 124 86 161 160

Watercraftk 1 18 3 15 33 30 24 43 23 60 70 59 128

Camping 88 104 103 71 56 121 116 121 116 94 115 92 12

Other sports 508 642 593 630 582 744 877 1516 1777 2279 3382 3433 3598

Total 3584 6052 7819 10 132 13 653 15 820 17 537 19 680 23 084 27 126 30 850 34 876 37 100

a Activities are listed in decreasing order of injury incidence. Bold text is used for the age of development with the highest number of injuries. b Bicycles and accessories. c Playgrounds and playground equipment. d Exercise and exercise equipment. e Lacrosse, rugby, and other miscellaneous ball games. f Mopeds, minibikes, other off-road vehicles. g Skating other than ice skating and inline skating, including roller skating. h Toboggans, sleds, snow discs, snowtubes. i Amusement attractions. j Water skiing, tubing, surfing. k Personal watercraft.

782 Volume 49 � Number 6 � December 2014

general, playground and bicycle injuries were the most common in the earlier ages of development, whereas team sports—especially basketball, football, and soccer— emerged as activities causing more injuries in later childhood and adolescent years.

The 5 leading sport- and recreation-related injury causes overall, throughout development—basketball, football, bicycling, playgrounds, and soccer are presented in the Figure. The 3 team sports—basketball, football, and soccer—showed a relatively similar trajectory: few injuries in early childhood, followed by a sharp increase in injuries around age 8 or 9 years, peaking in the middle teenage years, and then falling off rather sharply at 17 to 18 years. Basketball and football followed remarkably parallel trajectories, whereas soccer had a more muted peak. The 2 other most common causes of pediatric injury— playgrounds and bicycling—possessed very different path- ways across development. Playground injuries peaked in the early elementary school years and then showed a slow but consistent drop-off into very low numbers during the teenage years. Bicycling injuries peaked in the preteen

years but were fairly common throughout most of childhood.

Information on the secondary question of interest, sex disparities in sport and recreational injuries, is offered in Table 3. Wide disparities emerged, with boys incurring more than 85% of baseball, football, moped, and non- powder gun injuries, and girls incurring more than 85% of gymnastics, cheerleading, and softball injuries. Sex dispar- ities were absent in just a few sport and recreational activities: amusement attractions, ice skating, playgrounds and playground equipment, racket sports, soccer, track and field, and trampoline each had an injury incidence no greater than 55% for 1 sex.

DISCUSSION

Sport and recreational activities are generally safe, enjoyable, and healthy. Millions of youth in the United States and worldwide engage in sports and recreation daily without injury. Injuries, however, do occur and can dramatically affect physical and mental health. One critical aspect of preventing pediatric sport and recreational injuries is understanding how the injury risk varies across child and adolescent development. Such an understanding will help aid injury-prevention efforts by allowing experts to focus on specific causes and age groups.

Our results begin to address that need. We report the number of injuries incurred in the United States during an 8-year period, across 18 years of age, and for 39 sport and recreational activities. Examining just 1 year of age or just 1 type of sport or recreational activity offers substantial information. Rather than arduously reviewing the detailed information available in our tables, we discuss some of the more surprising data patterns and then address factors that may explain these findings.

Several individual sport and recreational activities showed injury patterns that surprised us. We did not anticipate, for example, that the largest number of bowling injuries might be incurred by young children—those 4 and 5 years old. We also did not expect so many—several hundred—toddlers (1–3 years old) to be injured by activities designed primarily for adolescents and adults, such as all-terrain vehicles, snowmobiles, fishing, and mopeds and minibikes. Also surprising was that exercising and exercise equipment was among the top 5 causes of injuries for 3 age categories: 1-year-olds, 2-year-olds, and 18-year-olds and that bicycle injuries persisted throughout all of child and adolescent development, placing it among the top 5 causes of sport and recreational injuries from ages 1 to 18 years.

Other results were expected. Playground and trampoline injuries were most prominent throughout early and middle childhood but were then replaced in prominence by team sports, with baseball as a top 5 injury cause at 7 years and team sports accounting for 4 of the top 5 causes of sport and recreational injuries from ages 11 to 18 years (baseball, basketball, football, and soccer). Interestingly, despite US football’s reputation as a physical contact sport, basketball caused more injuries to US youth than did football, which may be partly due to exposure issues. Very few girls play competitive football in the United States, but both boys and girls play basketball, both competitively and recreationally. More youth may also be engaged in recreational (playground,

Table 1. Extended From Previous Page

No. of Injuries by Age, y

14 15 16 17 18 Total

48 090 49 394 46 783 44 452 29 781 360 537

46 680 45 554 41 527 37 286 16 676 34 2314

24 261 18 494 13 291 9846 8543 319 840

1946 1446 916 813 591 210 648

16 326 15 961 14 537 12 777 6186 130 245

10 785 10 516 8552 7125 5371 118 380

13 527 11 902 8483 6805 5449 95 808

4022 3245 2021 1405 1222 86 257

6839 6973 7379 6331 6723 71 827

7916 8169 7456 5730 3375 68 160

5278 5663 4997 4452 3916 63 223

3622 3266 3092 2709 2160 61 483

6284 7167 5277 5230 5408 56 470

2023 1378 731 569 394 54 390

6343 8162 5953 4508 4807 54 114

6817 6991 6630 6838 4210 48 047

6390 7307 5363 4248 3168 46 155

5724 6251 6506 5088 2922 43 597

4962 5068 4018 3266 3334 36 981

2113 1490 1101 729 642 34 914

5392 5451 5018 4115 2417 33 215

1791 1290 1064 839 806 26 677

2177 2206 1864 1756 1537 22 564

1372 1294 1189 836 888 22 463

1257 1324 907 924 845 18 895

1120 836 672 474 407 16 671

2759 2585 2516 2011 967 15 701

684 589 601 605 505 15 257

1005 838 663 499 457 14 293

975 680 726 623 496 11 179

832 1051 1460 989 1231 9195

862 1231 1029 975 928 8734

318 407 316 364 399 6433

253 373 381 430 365 2837

307 265 191 269 234 2593

98 78 75 80 107 1817

169 133 325 276 391 1797

134 40 79 67 136 1667

3699 3541 3036 2889 2079 35 805

37 333 35 138 29 872 25 277 15 809 390 742

Journal of Athletic Training 783

driveway, or ‘‘pick-up’’) basketball nationwide than in football.

Our findings concerning the sex of injured children were largely as expected. Boys tended to have more injuries than girls in most categories, as has been reported in the broader child-injury literature.1 The sports that had the higher numbers of female injuries were those that are more prototypically engaged in by US girls—softball, gymnastics and cheerleading, horseback riding, and volleyball.

How might the findings be explained? Caution must be exercised in interpreting causality from our descriptive data analysis, but biological development likely plays some role. Perceptual, cognitive, and motor skills develop throughout childhood and may affect how youth engage in activities that require balance, coordination, decision-making, and other developmental skills. Misjudgments, missteps, and miscalculations—often developmentally driven—can result in injury.6

Sociocultural factors are also likely relevant. To state the obvious, children are more likely to be injured in the sport and recreational activities in which they engage. We were unable to adjust our analysis for exposure,7,8 but one would expect more pediatric basketball injuries than pediatric bowling injuries based on the assumption that US children spend more time playing basketball than they do bowling. Sociocultural factors also may play more subtle roles. Increased indepen- dence from supervision and a developmental tendency toward impulsive risk taking could contribute to the high rate of injuries in ‘‘adventure’’ activities such as tobogganing and sledding, scooters, skateboards, and skates in the early and middle adolescent years.

The role of sociocultural factors may be increasingly important if national calls to increase physical activity among youth are successful.9,10 That is, we might expect increased sports and recreational injuries as youth are increasingly exposed to risk. That risk may vary through child development, and identifying data trends will assist with injury-prevention efforts.

Like all research using large, archival data sets, such as the NEISS, this study has strengths and limitations. Strengths include the size and scope of the data set and its ability to address a wide range of injuries across ages and sport and recreational activities. However, we also cite several limitations. First, we were unable to control for exposure to sport or recreational activities or injury situations. Second, we lacked detail about specific injury events, including antecedents and consequences of individ- ual injury events, the particular types of injuries caused by each sport or recreational activity, or the severity of individual injuries. For example, exercise equipment

Table 2. Top 5 Sport and Recreational Injury Causes by Age Extended on Next Page

Rank

Activity by Age, y

1 2 3 4 5 6 7 8 9

1 Playgroundsa Playgroundsa Playgroundsa Playgroundsa Playgroundsa Playgroundsa Playgroundsa Bicyclesb Bicyclesb

2 Bicyclesb Bicyclesb Bicyclesb Bicyclesb Bicyclesb Bicyclesb Bicyclesb Playgroundsa Playgroundsa

3 Exercisec Trampolines Trampolines Trampolines Trampolines Trampolines Trampolines Trampolines Football

4 Swimming Exercisec Swimming Swimming Scooters Scooters Baseball Football Basketball

5 Trampolines Swimming Scooters Scooters Swimming Swimming Scooters Baseball Baseball

a Playgrounds and playground equipment. b Bicycles and accessories. c Exercise and exercise equipment.

Table 3. Percentage of Injuries Incurred by Each Sex Across Sport

and Recreational Activities

Activity

%

Males Females

Football 95 5

Combative 89 11

Skateboards 89 11

Mopeds and minibikesa 88 12

Baseball 86 14

Nonpowder guns 86 14

Fishing 83 17

Hockey 78 22

Snowmobiles 77 23

Water skiingb 75 25

Basketball 73 27

Bicyclesc 73 27

Go-carts 72 28

Snow skiing 71 29

All-terrain vehicles 70 30

Golf 68 32

Lacrosse/rugbyd 67 33

Billiards 65 35

Camping 64 36

Scooters 61 39

Tobogganing and sleddinge 61 39

Exercisef 59 41

Bowling 58 42

Swimming 58 42

Inline skating 56 44

Personal watercraft 56 44

Playgroundsg 55 45

Racquet sports 53 47

Soccer 53 47

Trampolines 53 47

Amusementh 49 51

Track and field 47 53

Ice skating 45 55

Roller skatingi 41 59

Volleyball 26 74

Horseback riding 25 75

Gymnastics and cheerleading 14 86

Softball 12 88

Other sports 59 41

a Mopeds, minibikes, and other off-road vehicles. b Water skiing, tubing, surfing. c Bicycles and accessories. d Lacrosse, rugby, and other miscellaneous ball games. e Toboggans, sleds, snow discs, snowtubes. f Exercise and exercise equipment. g Playgrounds and playground equipment. h Amusement attractions. i Skating other than ice skating and inline skating, including roller

skating.

784 Volume 49 � Number 6 � December 2014

injuries to young children were likely caused by toddlers catching their fingers in equipment that adults were using, rather than being injured while using the equipment themselves.11,12 Third, an understanding of the severity of injuries would be particularly helpful to future researchers. Swimming injuries may range, for example, from allergic rashes to life-altering spinal-cord injuries. Although there were slightly more basketball than football injuries overall, football injuries may be more severe (eg, head injuries, fractures) than basketball injuries (eg, sprains). Fourth, we relied on injury reports from EDs only and did not include injuries that still affected children and their parents but were treated in urgent care settings, primary caregiver offices, school athletic trainer or nurse offices, or elsewhere. Fifth, we lacked information about the geographic location where the injury occurred or where the patients lived. Future investigators might consider differences between sport and recreational injury incidence among rural, urban, and suburban patients.

In conclusion, we found that almost 37 children experienced a medically treated sport or recreational injury in the United States every hour. Team sports (eg, basketball, football, soccer), plus bicycling and play- grounds, were the most common causes of pediatric sport and recreational injuries, but injuries were caused by a range of activities. Injury incidences varied across child and adolescent development, with different activities peaking in incidence at different ages.

REFERENCES

1. Centers for Disease Control and Prevention. Web-based injury

statistics query and reporting system: the WISQARS Web site. http://

www.cdc.gov/injury/wisqars/index.html. Accessed December 11,

2013.

2. Finkelstein EA, Corso PS, Miller TR. The Incidence and Economic

Burden of Injuries in the United States. New York, NY: Oxford

University Press; 2006.

3. Agran PF, Winn D, Anderson C, Trent R, Walton-Haynes L. Rates of

pediatric and adolescent injuries by year of age. Pediatrics. 2001;

108(3):e45.

4. NEISS: the national electronic injury surveillance system—a tool for

researchers. United States Consumer Product Safety Commission

Web site. http://www.cpsc.gov//PageFiles/106626/2000d015.pdf.

Published March 2000. Accessed December 11, 2013.

5. Centers for Disease Control and Prevention. Nonfatal injury data.

http://www.cdc.gov/injury/wisqars/nonfatal.html. Accessed April 15,

2014.

6. Plumert JM. Relations between children’s overestimation of their

physical abilities and accident proneness. Dev Psychol. 1995;31(5):

866–876.