The Athletics Injury Prevention Programme Can Help to Reduce the Occurrence at Short Term of Participation Restriction Injury Complaints in Athletics: A Prospective Cohort Study

imed to determine whether an Athletics Injury Prevention Programme (AIPP), targeting the most common athletics injuries, can reduce the occurrence of injury complaints that lead to restrictions in athletics participation (participation restriction injury complaints) in the short (12 weeks) and long (40 weeks) terms. For our 40-week prospective cohort study (level of evidence 2), we invited inter-regional and national-level athletes to regularly perform the AIPP, which included 8 exercises addressing core stability, hamstring, leg and pelvic muscles strengthening and stretching, and balance exercises. A Cox regression was used to analyse the in uence of AIPP on the occurrence of

and long (40 weeks) terms. For our 40-week prospective cohort study (level of evidence 2), we invited inter-regional and national-level athletes to regularly perform the AIPP, which included 8 exercises addressing core stability, hamstring, leg and pelvic muscles strengthening and stretching, and balance exercises. A Cox regression was used to analyse the in uence of AIPP on the occurrence of participation restriction injury complaint, adjusted to sex, age, height, body mass, discipline, and history of injury complaints during the preceding season, individual response rate, mean weekly training time, mean weekly number of competition, presented by hazard ratio (HR) with 95% con dence interval (95% CI). At 12 weeks (n=62 athletes), the AIPP was signi cantly associated with a lower risk of participation restriction injury complaint HR=0.36 (95% CI: 0.15 to 0.86),p =0.02 and HR=0.29 (95% CI: 0.12 to 0.73),p=0.009, with cumulative weeks and cumulative training time as time scale, respectively, while at 40 weeks (n=53 athletes) there was no signi cant association. An 8-exercise injury prevention programme can e ectively help to reduce occurrence of injury complaints that would restrict an athlete's participation in athletics in the short term. Sports2020,8, 84; doi:10.3390 /sports8060084 /journal/sports

Sports2020,8, 84 2 of 14 Keywords: sports injury prevention; injury prevention program; athletics; track and eld; epidemiology; prospective studies 1. Introduction Athletics (Track and Field) participation leads to a risk of injuries [1]. Indeed, about 61%–76% of athletes incur at least one injury during any one season, and injury incidences from 3.6 to 3.9 injuries per 1000 h of athletics have been reported, varying with age, sex, and athletics disciplines [2–4]. Some injuries have been reported to be the most common, with injury diagnosis varying according to the discipline: hamstring muscle injuries (especially in sprints, hurdles, and jumps), Achilles tendinopathies (especially in sprints, jumps, middle- and long-distances), knee overuse injuries including patellar tendinopathies (especially in sprints, middle- and long-distances), shin splints and stress fractures (especially in sprints, middle- and long-distances), ankle sprains (especially in jumps and throws), and low back pain (especially in jumps and throws) [2–5]. Whatever the level, age or discipline, injury unfortunately a ects an athlete's life. Injuries may force athletes to reduce their training load (volume and/or intensity, so restricting their participation), cause them to drop out of a single competition, miss an entire season or, in the worst case scenario, bring their career to a premature end [1]. Directly or indirectly, injuries negatively in uence athletes' training, performance, and health [1,6,7]. Consequently, injury prevention strategies in athletics represents a win-win perspective for athletes, coaches, and medical sta [1,8,9]. To our knowledge, no injury prevention programme targeting athletics injuries is currently available, contrasting with the situation in team sports [10] (especially football (soccer) [11–13] and handball [14–16]) which already have scienti cally validated injury prevention programmes. These programmes include strengthening exercises and balance and coordination tasks, and have been shown to be e ective in reducing injury occurrence, as long as they are completed regularly [10–16]. Given the speci c constraints and injuries associated with athletics practice, developing and analysing the e cacy and/or e ectiveness of an injury prevention programme speci c to athletics is of interest. In order to cover the greatest possible population at risk of injury caused by athletics practice, such an

injury occurrence, as long as they are completed regularly [10–16]. Given the speci c constraints and injuries associated with athletics practice, developing and analysing the e cacy and/or e ectiveness of an injury prevention programme speci c to athletics is of interest. In order to cover the greatest possible population at risk of injury caused by athletics practice, such an injury prevention programme should target athletes of competitive level, and not exclusively elite athletes, ranging from youth (under 18 years) to adult (under 40 years) age categories, regardless of sex and discipline. In this context, the aim of this prospective cohort study was to determine whether an Athletics Injury Prevention Programme (AIPP), implemented in female and male competitive-level athletes ranging from 15 to 40 years, targeting the most common athletics injuries, can reduce the occurrence of injury complaints that lead to restrictions in athletics participation in the short (12 weeks) and long (40 weeks) terms. 2. Methods 2.1. Study Design For this 40-week prospective cohort study carried out during the 2014–2015 athletics season, we invited inter-regional and national-level athletes to regularly perform the AIPP. Then, to measure the e cacy of the programme, we asked the athletes to provide us, using a weekly online questionnaire, with data regarding their participation in the programme (i.e., AIPP), any injury complaints incurred and how these a ected their participation in athletics, training, and/or competition exposure. We also collected baseline information on each athlete at the start of the season (sex, age, height, body mass, athletic discipline, and history of injury complaints during the preceding season). The study protocol was reviewed and approved by the Saint-Etienne University Hospital Ethics Committee (IORG0004981).

Sports2020,8, 84 3 of 14 2.2. Participants At the start of the 2014–2015 season, the coaches of 12 athletics training groups from various clubs throughout France were approached. The objectives, procedure, and risks of the study were explained orally (PE) and followed up in writing. A total of 6 of the 12 coaches agreed to participate in this study. In these six training groups, athletes were then selected according to the following inclusion criteria: (1) training at least 3 times a week and engaged in competitive athletics, (2) without any contraindications for competitive athletics activity, and (3) aged from 15 to 40 years. Athletes were included irrespective of their baseline injury status or history [16], because excluding athletes with injury would have resulted in a biased study population not representative of athletes, where injuries are frequent [2–4,17]. Informed written consent was obtained from all participants in the study, and in addition from their parents for those under the age of 18 years. 2.3. Athletics Injury Prevention Programme and Implementation The AIPP was developed by a sports medicine physician specialised in athletics (P.E.) with the aim of targeting the most common athletics injuries (hamstring muscle injuries, Achilles and patellar tendinopathies, low back pain, ankle sprains) while being time e cient and feasible. The programme was based on the literature on the epidemiology of athletics injuries, injury risk factors, and current evidence-based injury prevention programmes. Validated exercises used successfully with other cohorts for primary and/or secondary prevention were selected: eccentric strengthening to prevent hamstring injuries [18,19], Achilles tendinopathies [20] and patellar tendinopathies [21]; strengthening and neuromuscular control to prevent ankle sprains [22]; and core stability to guard against low back pain [23]. Before starting the study, the AIPP was reviewed, tested and approved by athletes (n=7), athletics coaches (n=4), physiotherapists specialised in athletics (n=3, including R.D.), and physicians specialised in athletics (E.C., N.M., J.-M.S., F.D.). The AIPP included 8 exercises with levels of progression (from 2 to 5 depending on the exercise): core stability (plank and side plank), postural control (one-leg balance), pelvic strengthening (lunges and hip abductor strengthening), hamstring exercises (stretching

approved by athletes (n=7), athletics coaches (n=4), physiotherapists specialised in athletics (n=3, including R.D.), and physicians specialised in athletics (E.C., N.M., J.-M.S., F.D.). The AIPP included 8 exercises with levels of progression (from 2 to 5 depending on the exercise): core stability (plank and side plank), postural control (one-leg balance), pelvic strengthening (lunges and hip abductor strengthening), hamstring exercises (stretching and isometric, concentric and eccentric strengthening), and lower leg exercises (stretching and eccentric strengthening). The exercises, number of repetitions, and levels of progression are presented in Table. The AIPP was sent to all participating athletes and their coaches via e-mail in both paper and video versions, but no further guidance was given. Once the athletes were familiar with the exercises, the AIPP took about 15 min to complete. Athletes were to continue their habitual training and physical conditioning routines and it was left up to them whether and when to do the whole or part of the AIPP programme.

Sports2020,8, 84 4 of 14 Table 1.The Athletics Injury Prevention Programme used to reduce injury complaints in athletics athletes. Exercises Repetitions Bonus (If It is too Easy, Athlete can Increase Di culty) Core stability—the plank (4 sides: prone position, lateral, supine position, lateral): Level 1: both legs 15 s per side for 3 min 4 30 s for 6 min, then for 12 minLevel 2: alternate legs Level 3: unstable support Single leg balance: Level 1: static 3 15 s (each side) 3 30 s each sideLevel 2: unstable support Level 3: throwing ball with partner, then on unstable support Pelvis strengthening: Lunges 3 10 rep. 6 10 rep., then 6 10 rep. with medicine ball Hip abductor strengthening-Level 1: leg empty 3 10 rep. (each side) 6 10 rep. (each side), then unstable support Hip abductor strengthening-Level 2: with elastic 3 10 rep. (each side) 6 10 rep. (each side), then unstable support Hamstring exercises: Hamstring stretching (di erent positions) 3 15 s Hamstring strengthening: Level 1: isometric contraction on two legs 6 6 s 10 10 s Level 1: heel to buttock with elastic 3 6 s (each side) 5 10 s (each side) Level 2: isometric contraction on one leg 6 6 s (each side) 10 10 s (each side) Level 2: heel to buttock with elastic 3 6 s (each side) 5 10 s (each side) Level 3: Nordic hamstring with help of upper arms 1 5 rep., then 3 5 rep., then 6 6 rep. Level 4: Nordic hamstring 1 5 rep., then 3 5 rep., then 6 6 rep. Level 5: Pliometric 1 5 rep., then 3 5 rep., then 6 6 rep. Lower leg exercises: Lower leg stretching 3 15 s (each side) Lower leg strengthening: Level 1: down to the ground 3 8 rep. (each side) 3 10 rep., then 5 10 rep. each side and then increase load Level 2: down to the void 3 8 rep. (each side) 3 10 rep., then 5 10 rep. each side, and then increase loads s, seconds; rep., repetitions.

Lower leg strengthening: Level 1: down to the ground 3 8 rep. (each side) 3 10 rep., then 5 10 rep. each side and then increase load Level 2: down to the void 3 8 rep. (each side) 3 10 rep., then 5 10 rep. each side, and then increase loads s, seconds; rep., repetitions.

Sports2020,8, 84 5 of 14 2.4. Data Collection Regarding Participation in the AIPP, Exposure and Injury Complaints Every Monday during the 40-week period of the 2014–2015 season, all the athletes received an invitation by e-mail asking them to complete their online questionnaire to collect information on the preceding week: number of hours of training, participation in competitions (yes/no), number of complete AIPP sessions performed, and injury complaints. Additional e-mails were sent one and three months after the start of the season, encouraging them to fully participate in the study and contribute to the data collection. An injury complaint was de ned as: “A pain, physical complaint or musculoskeletal lesion sustained by an athlete during participation in athletics training or competition, regardless of whether it received medical attention or its consequences with respect to impairments in connection with competition or training” [24]. Injury complaints unrelated to athletics practice were not collected in this study. We chose using the term “injury complaint” since this was self-reported information without medical diagnosis [25]. We asked athletes to report on any injury complaints during the preceding week, using four possible categories [26,27]: no injury complaint, injury complaint allowing full participation, injury complaint necessitating reduced participation, injury complaint preventing any participation. The primary outcome of the present study was the occurrence of injury complaints that led to restrictions in athletics participation (participation restriction injury complaints), including both injury complaints necessitating reduced participation and injury complaints preventing any participation. Weekly, we asked athletes to report if they performed the AIPP during the preceding week. We asked athletes to report that they performed an AIPP session only if they had performed the entire programme of 8 exercises. Participation in the AIPP was expressed by the average number of AIPP sessions performed per week. Finally, an athlete's participation in the study was expressed by the individual response rate, calculated by dividing the total number of completed weekly questionnaires by the maximum number of responses possible (maximum being 12 or 40 for the short- or long-term analyses, respectively). We only included in the analysis athletes with a response rate 75%.

AIPP sessions performed per week. Finally, an athlete's participation in the study was expressed by the individual response rate, calculated by dividing the total number of completed weekly questionnaires by the maximum number of responses possible (maximum being 12 or 40 for the short- or long-term analyses, respectively). We only included in the analysis athletes with a response rate 75%. No imputations of data were performed. 2.5. Data Analysis Analyses were conducted at 12 and 40 weeks. Descriptive analyses were performed using mean and standard deviation (SD) for continuous variables, and numbers and percentages for ordinal or categorical variables. Normal distribution of the data was veri ed by the Shapiro–Wilk normality test. Comparisons between groups of athletes included in the analyses at 12 and 40 weeks were performed usingt-tests for continuous variables and Chi 2 -test for ordinal or categorical variables. We used a time-to-event approach for analyses [28]. Information after the rst occurrence of the primary outcome (i.e., participation restriction injury complaint) was not used in the present analyses (i.e., subsequent participation restriction injury complaints, response rate, AIPP, training and competition); we used the mean number of responses per week, the mean number of AIPP sessions per week, the mean number of training hours per week, and the mean number of competitions per week until the rst occurrence of the outcome. Time to rst event was analysed using (1) cumulative weeks and then (2) cumulative training time as time scale. The unit of analysis was the individual athlete. A Cox proportional hazards regression (or Cox regression) model was used to analyse the in uence of the AIPP on the occurrence of participation restriction injury complaint, adjusted to sex, age, height, body mass, discipline, and history of injury complaints during the preceding season (yes/no), individual response rate, mean weekly training time (except when time scale was cumulative weeks), and mean weekly number of competition. The hazard ratio (HR) with 95% con dence interval (95% CI) was presented for each variable, with the assumption that the HR was constant over time tested. Signi cance was accepted atp<0.05. All data were processed

the preceding season (yes/no), individual response rate, mean weekly training time (except when time scale was cumulative weeks), and mean weekly number of competition. The hazard ratio (HR) with 95% con dence interval (95% CI) was presented for each variable, with the assumption that the HR was constant over time tested. Signi cance was accepted atp<0.05. All data were processed using Excel and R (version 3.3.2, ©Copyright 2016 The Foundation for statistical Computing (Comprehensive R Archive Network, http://www.R-project.org)).

Sports2020,8, 84 6 of 14 3. Results 3.1. Participants Of the 140 athletes in the six training groups, 103 (73.6%) athletes met the inclusion criteria and responded at least once to the weekly questionnaire. Among these, 62 (44.3%) athletes (34 male and 28 female athletes) with an average age of 21.4 (SD 5.2) years, achieved a weekly response rate 75% at the time of the primary outcome occurrence over the 12-week period, and became the nal study group (Table). At 40 weeks, 53 (37.9% of the total) athletes had a response rate 75% at the time of the primary outcome occurrence over the 40-week period (Table). Hence, data from these 62 and 53 athletes were analysed at 12 and 40 weeks, respectively. A ow chart for cohort selection is presented in Figure. Analyses of the non-responders did not show any di erences in baseline characteristics with either the 103 athletes who met the inclusion criteria or the nal study groups. Table 2. Baseline characteristics of the athletics athletes included in the analyses at 12 and 40 weeks. Comparisons between groups at 12 and 40 weeks showed no signi cant di erences. At 12 Weeks (n=62) At 40 Weeks (n=53) Comparison between 12 and 40 Weeks Groups Anthropometric data (mean (SD)) Sex (M/F) (n) 34 /28 31 /22 Chi2 =0.16;p=0.69 Age (years) 21.4 (5.3) 23.6 (7.1) p=0.97 Height (cm) 175.4 (9.3) 175.5 (7.4) p=0.60 Body mass (kg) 64.3 (10.8) 64.7 (10.0) p=0.73 Body mass index (kg/m 2 ) 20.8 (2.0) 20.9 (2.0) p=0.89 History of injury complaints (n (%)) In the preceding season 47 (76.8) 41 (77.4) Chi2 =0.04;p=0.84 Disciplines (n (%)) Chi2=1.13;p=0.98 Sprints 17 (27.4) 14 (26.4) Hurdles 6 (9.7) 3 (5.7) Middle distances 7 (11.3) 5 (9.4) Long distances 3 (4.8) 3 (5.7) Jumps 6 (9.7) 6 (11.3) Throws 3 (4.8) 2 (3.8) Combined events 20 (32.3) 20 (37.7) M, male athletes; F, female athletes.Sports 2020, 8, x FOR PEER REVIEW 6 of 15 Figure 1. Flow chart showing the recruitment, dropout rate, and number of athletes included and analysed. 3.2. Short-Term Effect of the AIPP At 12 weeks,

The study evaluates the effectiveness of an injury prevention program for athletes.