CJSM Blog Journal Club — NMT to prevent ankle sprains in youth soccer and basketball athletes

Our Jr. Assoc Editor Dr Zaremski — already awarded an AMSSM Travelling Fellowship. Is there something bigger in his future?

It’s July, and our fourth edition of 2018 has just published.  One of the headlining pieces of original research we have in this edition is new work from the Sport Injury Prevention Centre in Calgary, Alberta Canada (chaired by Caroline Emery, the well-known researcher and author): Prevention of Ankle Sprain Injuries in Youth Soccer Cland Basketball: Effectiveness of a Neuromuscular Training Program

Our Jr. Assoc. Editor Jason L Zaremski, MD  is today reprising his role as guest author for the CJSM blog journal club  and will take us through his read of the study.  Join in the conversation over this important new, original research by reading the article, the journal club post below, and sharing your thoughts in the ‘reply’ section below this post, or on Twitter at @cjsmonline 

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Clinical Journal of Sport Medicine Blog Journal Club

Jason L Zaremski, MD, CAQSM, FACSM, FAAPMR

Title: Owoeye OBA, Palacios-Derflingher LM, Emery CA. Prevention of Ankle Sprain Injuries in Youth Soccer and Basketball: Effectiveness of a Neuromuscular Training Program and Examining Risk Factors.

Introduction:  The summer Journal Club commentary for the Clinical Journal of Sports Medicine will be an analysis of the new research examining the effects of injury reduction of ankle sprains in soccer and basketball using neuromuscular training (NMT) program in youth athletes. The secondary objective of this study included the evaluation of risk factors for Ankle Sprain Injury (ASI).

Methods:  This study was a secondary data analysis from 3 cohort studies and 2 randomized control trials (RCTs) over the course of 1 season of player in soccer and basketball from 2005-2011. There were a total of 2265 patients aged 11-18 years that play soccer and basketball in Alberta, Canada. Player characteristics (sex, age, weight, height, BMI, sport exposure time, previous ASI, previous lower extremity injury with and without ASI) were divided based upon if a player participated in a NMT program or did not. Frequency between all variables was very similar except for No NMT between females (n=952) and males (n=439) and sport participation without exposure to NMT (soccer = 965, basketball = 426). Average age, weight, height, and BMI were all similar. Exposure time for the NMT group was 72.56 (70.98-74.15) hours versus 62.92 (61.48-64.37) hours for No NMT group.

Secondary Data Analysis Studies: The five studies included in the secondary data analysis. See page 2 of the manuscript for further details of individual studies. Study 1 (Emery CA, et al. AJSM 2005) assessed overall injury rate in adolescent soccer players. Study 2 (Emery CA, AJSM 2006) evaluated overall injury rate in adolescent indoor soccer and outdoor soccer. Study 3 (Allen S, et al. CJSM 2010) calculated the overall injury rate in female youth soccer players using risk factors via pre-season musculoskeletal screening. Study 4 (Emery CA & Meeuwisse WH, BJSM 2010) measured the incidence of injury in HS basketball players using a basketball specific training program. Study 5 (Emery CA, et al, CJSM 2007) analyzed the usage of neuromuscular prevention strategies in youth soccer players. Of note, all five studies used the same baseline medical questionnaires, baseline assessments, injury report forms, and participation exposure data documentation.

Intervention/Treatment Arms:  The intervention was a NMT warm-up. This included aerobic, strength, agility, and balance components. Included in the NMT program was to have the NMT group observe a 15- to 20-minute home-based balance training program based upon previously reported studies.

Outcome Measures: The primary outcome measure was ASI sustained during sport participation that required medical attention and/or missed competition time per 1000 player hours.  Designation of missed time on an injury report was based upon the following definitions: A “full” session was assigned if the player had completed 75% to 100%, a “partial” session if a player had participated less than 75%, and “no participation” if the player missed the entire session because of injury, sickness, or other reasons. The authors recorded ASI using a validated prospective injury surveillance system consistent in all five studies. The authors additionally assessed for the injury risk based upon stratifying age, 11-15 y.o. and 16-18 y.o.

Statistical Measures:

As the authors write in their manuscript: Independent variables included NMT (primary exposure), sex, age, weight, height, BMI, sport, previous ASI, and previous lower extremity injury (LEI) (with or without previous ASI in the past 1 year). Participants with missing values were excluded from analyses.  Statistical analyses were performed using STATA (version 14.1, College Station, Texas).  Player characteristics were reported using descriptive statistics. Injury incidence rates (IRR) were expressed as number of injuries/1000 hours.  Variables including age, weight, height, and BMI were categorized from a continuous scale. Multivariable Poisson regression, controlling for clustering by team and offset for exposure hours, was used to estimate incidence rate ratios (IRRs) with 95% confidence intervals (CIs).

Results/Outcomes:

171 players reported 188 total ASIs. Results indicated that NMT reduced the risk of ASI by 32% [IRR = 0.68 (95% CI; 0.46-0.99)]. Additionally, independent risk factors for ASI included: 1) Previous ASI and 2) Participation in basketball over soccer. Interestingly, ASI was not predicted with BMI, sex, age, or previous lower extremity injury.

Strengths: This is a well-designed, clinically relevant study that provides an implementable program that may be instituted for prevention of injury. While the design of this study was a secondary data analysis, the consistency across all studies strengthened the results.

Limitations: As the authors note, they found only five studies which met inclusion criteria, and were therefore limited in their analysis of pooled data.  Furthermore, two of the five studies did not document use of ankle bracing, a known protective intervention and a covariate for regression analysis which they could not incorporate in their own calculations.  This limitation extends to other potential protective factors which were not analyzed, such as playing surface and balance tests.  Finally, a study looking at outcomes extending beyond one year would strengthen the reported findings.

Conclusion: The authors concluded that a NMT program is protective for ASI in youth soccer and basketball players by approximately 32%. In addition, risk of ASI in youth basketball is greater than in soccer, and players with a history of ASI are at greater risk of injury.

Practice Pearl: This study reinforces the principle that NMT programs do indeed provide an injury protective effect for ASI in youth soccer and basketball players. It is reasonable to conclude that youth athletes in all land based sports, particularly those that have sustained ASI in the past, would benefit from participation in such a program to reduce the likelihood of ASI.