Running-Related Overuse Injuries and Their Relationship with Run and Resistance Training Characteristics in Adult Recreational Runners: A Cross-Sectional Study

his study aimed to characterize running-related injuries (RRIs), explore their relationship with run and resistance training (RT) parameters, and identify perceived prevention measures among adult recreational runners. An anonymous online survey was designed and distributed via social media and email. Data were analyzed with chi-square,t-test, or analysis of variance (ANOVA), with signi cance accepted atp 0.05. Data from 616 participants (76.8% female, age: 42.3 10.5 y) were analyzed. Most runners (84.4%) had an injury history, with 44.6% experiencing one in the past year. The most common RRI sites included the foot/ankle (30.9%) and knee (22.2%). RRI prevalence was higher in those running >19 miles weekly (48.4%,p= 0.05), but there were no differences based on RT participation status. Among those using RT, relatively more RRIs were observed in runners who trained the hip musculature (50.3%,p= 0.005) and did not include the upper body (61.6%,p< 0.001).

most common RRI sites included the foot/ankle (30.9%) and knee (22.2%). RRI prevalence was higher in those running >19 miles weekly (48.4%,p= 0.05), but there were no differences based on RT participation status. Among those using RT, relatively more RRIs were observed in runners who trained the hip musculature (50.3%,p= 0.005) and did not include the upper body (61.6%,p< 0.001). A disproportionately high RRI prevalence was found for several of the other risk-reduction strategies. RRIs remain a substantial problem, particularly around the ankle/foot and knee. Higher run volume and performance motives were positively associated with RRIs. Most runners incorporated RRI risk-reduction techniques, with over half using RT. The current study did not determine whether preventative strategies were implemented before or after injury; therefore, prospective studies controlling for previous injuries are required to evaluate the effectiveness of RT in preventing future RRIs. Keywords: running-related injury prevalence; recreational runners; resistance training; injury prevention 1. Introduction Practical, ef cient, and accessible, running is one of the most popular exercise modes worldwide, with involvement continuing to rise [1,2]. Along with higher participation rates, runner characteristics have evolved over the decades to include more female participants, a slower average pace, a higher average age [1], and those with health versus performance motives [1,3]. The current runner demographics exemplify the more casual, social, or recreational runner [4], who falls between novice and sub-elite or elite and ostensibly represents most of the running populace. Recreational athletes may indeed reap the countless health bene ts associated with running, including weight loss, cardiorespiratory tness, lipoprotein pro les, mental health, and increased lifespan [5–7], but these rewards are concomitant with a high running-related injury (RRI) risk—de ned herein as “running-related (training or competition) muscu- loskeletal pain in the lower limbs that causes a restriction or stoppage of running (distance, J. Funct. Morphol. Kinesiol.2023,8, 128.

J. Funct. Morphol. Kinesiol.2023,8, 128 2 of 11 speed, duration, or training) for at least 7 days or 3 consecutive scheduled training sessions, or that requires the runners to consult a physician or other health professional” [8] (p. 375). RRIs are associated with direct and indirect costs (i.e., healthcare, time away from work) and represent a considerable economic burden [9,10]. Additionally, a history of an RRI is the main determinant of future RRIs and the primary reason people quit running[11,12]. Due to heterogeneous reporting methods and inconsistent de nitions [8,13], RRI prevalence varies widely from 10 to 90%, with an average of 42.7% of runners experiencing an RRI annually [14,15]. Notably, these prevalence data were an amalgamation of novice to elite runners, triathletes, and orienteers and did not provide a unifying de nition of RRI or delineate between the different athlete types, sex, age, or run distance. The popularity of running, its indisputable bene ts, and the high likelihood of nefari- ous outcomes highlight the necessity of incorporating RRI risk-reduction strategies. Efforts to reduce RRIs are not novel, but evidence of effective strategies remains elusive, likely due to the complexity of RRIs' etiologies. Nonetheless, RRIs are universally characterized as a load–capacity imbalance [16], and while reducing RRIs requires a multifaceted approach, focusing on modi able factors to improve runners' capacity is imperative. Salient modi - able factors include strength and neuromuscular insuf ciencies [17–21] and posture control or balance de cits [19,22,23]. Resistance training (RT), sometimes referred to as “weight” or “strength” training and described herein as requiring the body to resist an external force or load, can elicit positive neuromusculoskeletal adaptations, improving intrinsic capacity. For example, various RT modalities, from body weight to heavy load exercises, can correct strength imbalances; increase bone density; and improve overall strength, speed, power, balance, coordination, and posture control [24,25]. RT is posited to reduce injury prevalence in team sports [26]; however, the relation- ship between RT participation status and RRIs is equivocal among recreational runners. Two studies aimed to investigate the relationship between RT participation and RRIs in recreational runners [27,28], both reporting

imbalances; increase bone density; and improve overall strength, speed, power, balance, coordination, and posture control [24,25]. RT is posited to reduce injury prevalence in team sports [26]; however, the relation- ship between RT participation status and RRIs is equivocal among recreational runners. Two studies aimed to investigate the relationship between RT participation and RRIs in recreational runners [27,28], both reporting no bene t or association. However, Toresdahl et al. [27] did not account for RT participation in their observational group and reported poor compliance in the RT group. Voight et al. [28] found no association between RRIs and cross-training, but cycling was the most common cross-training modality, with RT representing only a small percentage. Moreover, no studies have investigated the speci c RT programming parameters as they relate to RRIs, and little is known about the proportion of recreational runners who use RT to reduce RRIs or what other measures are perceived to achieve this goal. Thus, this study aimed to characterize overuse running-related injuries (RRIs), explore their relationship with speci c run and resistance training (RT) parameters, and identify perceived prevention strategies among adult recreational runners. Uniquely, the current study: (a) used Yamato et al.'s [8] consensus de nition of RRIs to assess overuse injuries, which are the most common RRI among distance runners [15]; (b) explicitly tar- geted recreational runners, de ned as running an average of at least 2 times per week for at least a year, and considering running their primary exercise mode; (c) examined RRI's association with RT participation and speci c program parameters for all participants and by sex, age, and run distance; and (d) identi ed perceived prevention strategies currently in use. 2. Materials and Methods 2.1. Participants Following institutional review board (IRB) approval, volunteers were recruited using a combination of non-probability purposeful convenience and snowball sampling. Inclusion criteria included recreational runners aged 18–65 who considered running their primary exercise mode and averaged at least 2 weekly runs for at least 1 year. Familiarity with the English language and internet access were requisite for study participation.

approval, volunteers were recruited using a combination of non-probability purposeful convenience and snowball sampling. Inclusion criteria included recreational runners aged 18–65 who considered running their primary exercise mode and averaged at least 2 weekly runs for at least 1 year. Familiarity with the English language and internet access were requisite for study participation.

J. Funct. Morphol. Kinesiol.2023,8, 128 3 of 11 2.2. Procedures This study used a quantitative, cross-sectional, online survey design. A 4-part survey was created with in uence from related surveys [29–38] to reduce bias in question creation and promote consistency within the eld. Each section (running history, RT characteristics, injury history, and standard demographics) had 2–11 questions, depending on the answers selected. The running-speci c questions asked about years of experience, frequency, weekly distance, duration, and reasons for running. RT questions addressed participation status, experience, frequency, duration, workout parameters (i.e., sets, repetitions, effort level, type of RT, and targeted muscles), and reasons for participation. The RRI segment began with a de nition of an overuse RRI that was adapted from other researchers [8]. Questions were asked about RRI history, the RRI prevalence in the past year, and the RRI location and severity if one was present. This section also assessed the use of perceived injury-prevention strategies. The survey underwent unbiased peer review and was piloted with a small subset of the population for feedback and readability. A web-based Flesch–Kincaid readability test indicated a 7th–8th grade reading level, which is considered adequate for those 18 years and older. A brief study overview, an invitation to participate, and the Qualtrics (Provo, UT, USA) survey link were distributed broadly via Facebook (Menlo Park, CA, USA) and email lists with encouragement to share among other recreational runners. Survey questions were available only after agreeing to informed consent and eligibility criteria. 2.3. Statistical Analysis All data were analyzed with IMB SPSS Statistics version 28 (Chicago, IL, USA). G*power's (Aichach, Germany) minimum sample size for chi-square with a medium effect (Cohen's W = 0.3), powered at 80%, and 5 degrees of freedom, was 143. Descriptive statistics are presented as mean and standard deviation (continuous variables) or frequency with percentage (categorical data). The survey questions yielded predominantly ordinal and nominal data. Cross-tabulation with chi-square analysis determined associations be- tween the categorical variables. Independentt-tests or analysis of variance (ANOVA) were used for continuous data (e.g., years of experience). Signi cance was accepted atp 0.05 for all, and a

are presented as mean and standard deviation (continuous variables) or frequency with percentage (categorical data). The survey questions yielded predominantly ordinal and nominal data. Cross-tabulation with chi-square analysis determined associations be- tween the categorical variables. Independentt-tests or analysis of variance (ANOVA) were used for continuous data (e.g., years of experience). Signi cance was accepted atp 0.05 for all, and a post hoc Bonferroni correction was applied when omnibus signi cance was determined from the cross-tabulated chi-square analyses. Missing values were excluded from the analysis. 3. Results 3.1. Participants Data from 616 eligible volunteers (76.8% female, M SD, age: 42.3 10.5 y, body mass index (BMI) = 23.6 3.6 kg m 2 ) were included in the analyses. On average, participants had about 13 years of experience and ran approximately four times per week, totaling 3–6 h.There were slight but statistically signi cant sex differences: men had a higher BMI and ran more frequently, while women had more running experience (Table). Table 1.Participant characteristics. Variable All Female Male Total 616 (100%) 473 (76.8%) 143 (23.2%) Age (y) 42.3 10.5 42.3 10.1 42.3 11.8 BMI (kg m 2 ) 23.6 3.6 23.3 3.7 24.9 3.2 *** Education High school or equivalent 29 (4.7%) 14 (3%) 15 (10.5%) ** Trade/technical 20 (3.2%) 15 (3.2%) 5 (3.5%) Associates 22 (3.6%) 14 (3%) 8 (5.6%) Bachelors 202 (32.8%) 155 (32.8%) 47 (32.9%) Masters/doctorate 342 (55.5%) 275 (58.1%) 67 (46.9%)

J. Funct. Morphol. Kinesiol.2023,8, 128 4 of 11 Table 1.Cont. Variable All Female Male Community Urban 130 (21.1%) 97 (20.5%) 33 (23.1%) Suburban 374 (60.7%) 295 (62.4%) 79 (55.2%) Rural 111 (18%) 81 (17.1%) 30 (21%) Race Asian/Paci c Islander 12 (1.9%) 7 (1.5%) 5 (3.5%) Black/African American 5 (0.8%) 5 (1.1%) - Native American/Alaskan 1 (0.2%) - 1 (0.7%) White/Caucasian 565 (91.7%) 436 (92.2%) 129 (90.2%) Bi- or multi-racial 13 (2.1%) 10 (2.1%) 3 (2.1%) Other 19 (3.1%) 14 (3.0%) 5 (3.5%) Run experience (y) 12.8 9.6 13.3 9.6 * 11.3 9.7 Frequency (d/wk) 3.95 1.3 3.9 1.2 4.3 1.4 ** Weekly distance (miles) 19 298 (48.4%) 242 (51.2%) 56 (39.2%) >19 318 (51.6%) 231 (48.8%) 87 (60.8%) * Weekly duration (h) 1–2 79 (12.8%) 60 (12.7%) 19 (13.3%) 3–4 22 8 (37%) 186 (39.3%) 42 (29.4%) 5–6 18 1 (29.4%) 136 (28.8%) 45 (31.5%) 7+ 128 (20.8%) 91 (19.2%) 37 (25.9%) Note. Continuous data are presented asM SD.Categorical data are presented as frequency (n) and percentage. BMI = body mass index. *p< 0.05, **p< 0.01, ***p< 0.001. 3.2. Injury Prevalence and Characteristics RRI prevalence for all runners and by sex, age, and run-distance categories are pre- sented in Table. Nearly 85% of participants had a history of RRI, and about 45% reported one in the past year, with similar proportions across sex and age categories. RRI prevalence in the past year was higher than expected among those who ran >19 miles per week (48.4%), 2(1) = 3.81,p= 0.05, and for those that selected “performance” as a dominant reason for running (51.3%), 2(1) = 4.87,p= 0.03. Runners in the 51–65 age category were more likely than expected to experience an injury requiring moderate (vs. mild or major) training modi cations (50%), 2 (1) = 10.86,p= 0.03. Table 2.Injury characteristics by frequency and percentage. Variable Category ( n) History of RRI RRI in the Past Year Total (n= 616) 520 (84.4%) 275 (44.6%) Sex F (n= 473) 398 (84.1%) 202 (42.7%) M (n= 143) 122 (85.3%) 73 (51.0%) p 0.74 0.08 Age 18–34 (n= 144) 120 (83.3%) 71 (49.3%) 35–50

cations (50%), 2 (1) = 10.86,p= 0.03. Table 2.Injury characteristics by frequency and percentage. Variable Category ( n) History of RRI RRI in the Past Year Total (n= 616) 520 (84.4%) 275 (44.6%) Sex F (n= 473) 398 (84.1%) 202 (42.7%) M (n= 143) 122 (85.3%) 73 (51.0%) p 0.74 0.08 Age 18–34 (n= 144) 120 (83.3%) 71 (49.3%) 35–50 (n= 327) 277 (84.7%) 140 (42.8%) 51–65 (n= 145) 123 (84.8%) 64 (44.1%) p 0.92 0.42 Run (miles/wk) <19 (n= 298) 250 (83.9%) 121 (40.6%) 19+ (n= 318) 270 (84.9%) 154 (48.4%) * p 0.73 0.05 Note. RRI = running-related injury. F = female, M = male. *p 0.05. RRIs occurred most frequently at the foot/ankle (30.9%), knee (22.2%), hip/groin (17.5%), and calf/Achilles (16.4%), as presented in Figure. The proportion of RRIs at the calf/Achilles was higher than expected for men versus women (26.0% and 12.9%,

J. Funct. Morphol. Kinesiol.2023,8, 128 5 of 11 respectively), 2(6) = 14.32,p= 0.03. No other signi cant differences in injury location were determined across sex, age, and run-distance categories.J. Funct. Morphol. Kinesiol. 2023, 8, x FOR PEER REVIEW 5 of 11 Note. RRI = running-related injury. F = female, M = male. * p  0.05. RRIs occurred most frequently at the foot/ankle (30.9%), knee (22.2%), hip/groin (17.5%), and calf/Achilles (16.4%), as presented in Figure 1. The proportion of RRIs at the calf/Achilles was higher than expected for men versus women (26.0% and 12.9%, respec- tively), χ 2 (6) = 14.32, p = 0.03. No other significant differences in injury location were de- termined across sex, age, and run-distance categories. Figure 1. Percentage of injuries by anatomical location. 3.3. Relationships with Resistance Training Characteristics No differences (p > 0.05) in RRI prevalence were observed between those who used RT and those who did not, which was consistent across sex, age, and run-distance catego- ries (Table 3). Regarding RRI severity, sub-analysis showed that among those in the 35–50 age category who did not participate in RT, there was a lower proportion (14.3%) than expected of moderate RRI-related training modifications (p = 0.03). Table 3. Running-related injuries and resistance-training status across sex, age, and run-distance categories. RRI in Past Year p RRI Severity p Yes No Mild Moderate Major All 0.49 0.13 Yes 195 (45.6%) 233 (54.4%) 57 (29.2%) 73 (37.4%) 65 (33.3%) No 80 (42.6%) 108 (57.4%) 30 (37.5%) 20 (25.0%) 30 (37.5%) Sex Female 0.08 0.37 Yes 156 (45.1%) 190 (54.9%) 47 (30.1%) 61 (39.1%) 48 (30.8%) No 46 (36.2%) 81 (63.8%) 15 (32.6%) 13 (28.3%) 18 (39.1%) Male 0.33 0.24 Yes 39 (47.6%) 43 (52.4%) 10 (25.6%) 12 (30.8%) 17 (43.6%) No 34 (55.7%) 27 (44.3%) 15 (44.1%) 7 (20.6%) 12 (35.3%) Age 18–34 Figure 1.Percentage of injuries by anatomical location. 3.3. Relationships with Resistance Training Characteristics No differences (p> 0.05) in RRI prevalence were observed between those who used RT and those who did not, which was consistent across sex, age, and run-distance categories (Table). Regarding RRI severity,

17 (43.6%) No 34 (55.7%) 27 (44.3%) 15 (44.1%) 7 (20.6%) 12 (35.3%) Age 18–34 Figure 1.Percentage of injuries by anatomical location. 3.3. Relationships with Resistance Training Characteristics No differences (p> 0.05) in RRI prevalence were observed between those who used RT and those who did not, which was consistent across sex, age, and run-distance categories (Table). Regarding RRI severity, sub-analysis showed that among those in the 35–50 age category who did not participate in RT, there was a lower proportion (14.3%) than expected of moderate RRI-related training modi cations (p= 0.03). Table 3. Running-related injuries and resistance-training status across sex, age, and run-distance categories. RRI in Past Year p RRI Severity p Yes No Mild Moderate Major All 0.49 0.13 Yes 195 (45.6%) 233 (54.4%) 57 (29.2%) 73 (37.4%) 65 (33.3%) No 80 (42.6%) 108 (57.4%) 30 (37.5%) 20 (25.0%) 30 (37.5%) Sex Female 0.08 0.37 Yes 156 (45.1%) 190 (54.9%) 47 (30.1%) 61 (39.1%) 48 (30.8%) No 46 (36.2%) 81 (63.8%) 15 (32.6%) 13 (28.3%) 18 (39.1%) Male 0.33 0.24 Yes 39 (47.6%) 43 (52.4%) 10 (25.6%) 12 (30.8%) 17 (43.6%) No 34 (55.7%) 27 (44.3%) 15 (44.1%) 7 (20.6%) 12 (35.3%) Age 18–34 Yes 51 (50.0%) 51 (50.0%) 0.80 14 (27.5%) 14 (27.5%) 23 (45.1%) 0.33 No 20 (47.6%) 22 (52.4%) 9 (45.0%) 5 (25.0%) 6 (30.0%) 35–50 Yes 98 (43.2%) 129 (56.8%) 0.84 32 (32.7%) 36 (36.7%) 30 (30.6%) 0.03 No 42 (42.0%) 58 (58.0%) 18 (42.9%) 6 (14.3%) * 18 (42.9%) 51–65 Yes 46 (46.5%) 53 (53.5%) 0.41 11 (23.9%) 23 (50.0%) 12 (26.1%) 0.76 No 18 (39.1%) 28 (60.9%) 3 (16.7%) 9 (50.0%) 6 (33.3%)

J. Funct. Morphol. Kinesiol.2023,8, 128 6 of 11 Table 3.Cont. RRI in Past Year p RRI Severity p Yes No Mild Moderate Major Run Distance (miles) 19 Yes 89 (41.8%) 124 (58.2%) 0.51 31 (34.8%) 36 (40.4%) 22 (24.7%) 0.06 No 32 (37.6%) 53 (62.4%) 9 (28.1%) 8 (25.0%) 15 (46.9%) >19 miles Yes 106 (57.3%) 79 (42.7%) 0.65 26 (24.5%) 37 (34.9%) 43 (40.6%) 0.06 No 48 (49.3%) 55 (53.4%) 21 (43.8%) 12 (25.0%) 15 (31.3%) Note. RT = resistance training. RRI = running-related injury. RRI severity re ects the extent to which training was altered. Data are presented as frequency (n) and percentage. In the case of omnibus signi cance, a post hoc Bonferroni adjustment was applied. *p< 0.001 after Bonferroni adjustment. A disproportionately high number of RRIs was observed in runners that included hip musculature in their RT (50.3%), 2(1) = 7.97,p= 0.005, and in those that did not include the upper body musculature in their RT (61.6%), 2(1) = 13.25,p< 0.001. Runners who selected “general health” as a reason for using RT were less likely than expected to have an RRI (42.1%), 2(1) = 8.98,p= 0.003, while those using RT for performance gains were more likely to have an RRI (50.2%), 2(1) = 4.23,p= 0.04. The 40.4% of runners following a personalized RT program—developed by an exercise professional such as a personal trainer, strength coach, or physical therapist—had a relatively higher RRI prevalence (52%), 2(1) = 4.89, p= 0.03.Signi cant differences in RRI prevalence and severity were not observed (p> 0.05) across RT years of experience, duration of sessions, sets, repetitions, effort, and type of modality used (Table). Table 4.Resistance-training characteristics by running-related injury status. Characteristics RRI in Past Year p Yes (n= 195) No ( n= 233) RT experience (y) 8.6 9.1 9.5 9.0 0.32 RT frequency (d/wk) 2.6 1.2 2.5 1.1 0.44 RT min/session 30–44 (72, 44.7%) 30–44 (89, 55.3%) 0.62 Repetition range 7–12 (128, 46.4%) 7–12 (148, 53.6%) 0.99 Effort level (0–10) 6.2 1.4 6.2 1.4 0.66 Note. RT = resistance training. RRI = running-related injury. Data are presented asM SDor as mode

The study investigates the prevalence and characteristics of running-related injuries among recreational runners.