High School Cross-country Runners Research Articles

Performance Perfectionism And Sport Specialization In High School Cross Country Runners

Performance Perfectionism And Sport Specialization In High School Cross Country Runners

Associations Between Menstrual Dysfunction, Training Mileage, Attitudes And Running-Related Injury In High School Cross-Country Runners

Associations Between Menstrual Dysfunction, Training Mileage, Attitudes And Running-Related Injury In High School Cross-Country Runners

Global Positioning System Watches and Electronic Journals: Are Training-Load Measures Similar in High School Cross-Country Runners?

Running programs are designed to progress training loads by manipulating the duration, frequency, and/or intensity of running sessions. While some studies use journals to monitor training load, others have used wearable technology. The purpose of this study was to compare the validity of self-reported and global positioning system (GPS)-watch-derived measures of external and internal loads in high school cross-country runners. Twenty-two high school cross-country runners participated in the study during fall 2020. Participants recorded running sessions using a GPS watch and self-reported the running session using an electronic journal. External (distance and duration) and internal loads (session rating of perceived exertion [sRPE], average, and maximum heart rate) were retrieved from the GPS watch and electronic journal. Correlations compared relationships, and Bland-Altman plots compared agreements between GPS-watch-derived and self-reported measures of training loads. We found moderate relationships between self-reported and GPS-watch-derived measures of external loads (distance: r = .76, moving duration: r = .74, and elapsed duration: r = .70) and poor relationships between internal loads (sRPE vs average heart rate: ρ = .11, sRPE vs maximal heart rate: ρ = .13). We found mean differences of -0.8km (95% = -6.3 to +4.8km) for distance, -4.5minutes (95% = -27.8 to +33.2min) for moving duration, and 2.7 minutes (95% = -27.8min to +33.2min) for elapsed duration. High school runners overreported running distance and duration using self-reports, and self-reported and GPS-watch-derived measures of internal loads demonstrated poor agreement. Coaches and clinicians should use caution when comparing results from studies using different methods of monitoring training loads.

Quantification Method and Training Load Changes in High School Cross-Country Runners Across a Competitive Season.

Running programs traditionally monitor external loads (eg, time and distance). Recent efforts have encouraged a more comprehensive approach to also account for internal loads (eg, intensity, measured as the session rating of perceived exertion [sRPE]). The combination of external and internal loads accounts for the possible interaction between these loads. Although weekly changes in training loads have been reported between external loads and the combination of external and internal loads during 2- and 4-week training cycles, no authors have indicated whether these differences occur during an entire cross-country season in high school runners. To compare changes in training loads, as measured by (1) external loads and (2) combined external and internal loads in high school runners during an interscholastic cross-country season. Case series. Community-based setting with daily online surveys. Twenty-four high school cross-country runners (females = 14, males = 10, age = 15.9 ± 1.1 years, running experience = 9.9 ± 3.2 years). Week-to-week percentage changes in training load were measured by external loads (time, distance) and combined external and internal loads (time × sRPE [timeRPE] and distance × sRPE [distanceRPE]). Overall, the average weekly change was 7.1% greater for distanceRPE than for distance (P = .04, d = 0.18). When the weekly running duration decreased, we found the average weekly change was 5.2% greater for distanceRPE than for timeRPE (P = .03, d = 0.24). When the weekly running duration was maintained or increased, the average weekly change was 10% to 15% greater when external and internal loads were combined versus external loads alone, but these differences were nonsignificant (P = .11-.22, d = 0.19-0.34). Progression in the training load may be underestimated when relying solely on external loads. The interaction between internal loads (sRPE) and external loads (distance or time) appears to provide a different measure of the training stresses experienced by runners than external loads alone.

Adolescent Endurance Runners Exhibit Suboptimal Energy Availability and Intakes of Key Nutrients

Backgroud: Despite the evidence of an elevated prevalence of low bone mass in adolescent endurance runners, reports on dietary intake in this population is limited. Objectives: This study aimed to evaluate energy availability (EA) and dietary intake among 72 (n = 60 female, n = 12 male) high school cross-country runners. Methods: The sample consisted of a combined dataset of two cohorts. In both cohorts, the Block Food Frequency Questionnaire (FFQ; 2005 & 2014 versions) assessed dietary intake. Fat free mass was assessed using dual-energy x-ray absorptiometry or bioelectrical impedance analysis. Results: Mean EA was less than recommended (45 kcal/kgFFM/day) among male (35.8 ± 14.4 kcal/kg FFM/day) and female endurance runners (29.6 ± 17.4 kcal/kgFFM/day), with 30.0% of males and 60.0% of females meeting criteria for low EA (<30 kcal/kgFFM/day). Calorie intake for male (2,614.2 ± 861.8 kcal/day) and female (1,879.5 ± 723.6 kcal/day) endurance runners fell below the estimated energy requirement for “active” boys (>3,100 kcal/day) and girls (>2,300 kcal/day). Female endurance runners’ relative carbohydrate intake (4.9 ± 2.1 g/kg/day) also fell below recommended levels (6-10 g/kg/day). Male and female endurance runners exhibited below-recommended intakes of calcium, vitamin D, potassium, fruit, vegetables, grains, and dairy. Compared to male endurance runners, female endurance runners demonstrated lower relative intakes of energy (kcal/kg/day), protein (g/kg/day), fat (g/kg/day), fiber, vegetables, total protein, and oils. Conclusion: This study provides evidence of the nutritional risk of adolescent endurance runners and underscores the importance of nutritional support efforts in this population.

Differences in Lower Extremity Kinematics Between High School Cross-Country and Young Adult Recreational Runners

BackgroundWhile previous research has assessed running kinematics for age-related differences that could increase the risk of a running-related injury, none of these studies have included high school aged runners or assessed running kinematics using 2-dimensional video analysis.PurposeThe purpose of this study was to compare sagittal plane kinematics during treadmill running in high school cross-country and young adult recreational runners using 2-dimensional motion analysis techniques.MethodsTwenty-five high school cross-country runners (13 women, 12 men) and 25 young adult recreational runners (12 women, 13 men) consented to participate in this study. Reflective markers were placed on each lower extremity over multiple anatomical landmarks. After a five-minute acclimation period in which the participants ran on a treadmill at their preferred running speed, video data were recorded at 240 frames per second for all participants while they continued to run on the treadmill.ResultsThere were no significant differences between left and right extremities. The young adult recreational runners exhibited significantly greater vertical excursion of the center of mass (t = 4.64, p = .0001) compared to the high school runners. There was no significant difference between the two age groups regarding the six other sagittal plane variables.ConclusionsThe young adult recreational runners demonstrated an increased center-of-mass vertical excursion in comparison to high school cross-country runners. In addition, the results obtained in this study for kinematic variables using 2-dimensional motion analysis were similar to previously reported studies using 3-dimensional motion analysis, demonstrating that 2-dimensional motion analysis could be used for analyzing sagittal plane running kinematics in clinical settings.Level of Evidence4, Controlled laboratory study

Factors Associated With Self-Selected Step Rates Between Collegiate and High School Cross Country Runners.

Introduction: Cross country is a popular high school and collegiate sport with a high rate of running-related injuries (RRI). Among high school runners, higher step rates have been associated with greater running experience and decreased body height, and lower step rates have been prospectively associated with increased risk of shin RRI. These associations have not been reported in collegiate cross country runners. The purpose of this study was to compare step rates between collegiate and high school cross country runners. Secondary objectives included determining if step rates in collegiate runners were related to experience and anthropometric variables, and whether their self-selected step rates were prospectively related to lower extremity RRI.Materials and methods: Twenty-nine NCAA Division III collegiate cross country runners (13 females, mean ± SD age 19.7 ± 1.3 years) completed a survey and ran at their self-selected speed. Step rate was assessed with Polar RCX5 wristwatches and S3+ Stride Sensors™ on the first day of the season. Runners were followed during the season for occurrence of time-loss lower extremity RRI. A cohort of 68 high school runners was used for comparison of step rates at their self-selected speeds.Results: Collegiate runners' self-selected step rates (177.1 ± 7.2 spm [steps per minute]) were higher than high school runners' (171.3 ± 8.3 spm) (p = 0.01). Collegiate runners ran at higher self-selected speeds (4.6 ± 0.5 m/s) than the high school runners (3.8 ± 0.5 m/s) (p < 0.001). A lower percentage of collegiate runners ran at ≤166 spm than high school runners. Body mass was negatively correlated with step rate in collegiate runners. During the season, 41.3% of collegiate runners experienced lower extremity RRI. Step rates for collegiate runners who did not experience RRI (178.9 ± 7.7 spm) were not significantly higher than runners who did experience RRI (174.5 ± 5.7 spm) (p = 0.10).Discussion: Higher step rates were found in collegiate than high school runners, but the difference was partially explained by higher self-selected running speeds. Thus, variations in step rate between high school and collegiate runners may be expected based on experience, speed, and body mass.

Comparison of different measures to monitor week-to-week changes in training load in high school runners

Training load is commonly used to monitor training stress and is the product of external and internal physiological loads experienced by an athlete. With emerging wearable technology, it is possible to evolve existing external load measurement from duration or distance to runner-specific biomechanical data, which when combined with existing measures of internal load such as session rating of perceived exertion (sRPE), may improve the quantification of training stress. This study compared week-to-week changes in training duration with different training loads obtained from common and more individualized measures of external load. The training of nine male high school cross-country runners from the same team undertaking the same training program was monitored for two consecutive weeks. This two-week cycle included a “coach-prescribed” low and high training load week. Training loads were calculated with sRPE and external load measures including: duration (minutes), Step Count, “Bone Stimulus” (IMeasureU), and cumulative vertical force. Weekly distances (in miles) were also measured. Between-week percent change (%Δ) was compared among training loads and minutes using paired t-tests and Cohen’s d effect size. Different %Δ were found between sRPExMinutes (%Δ=65 ± 25%; p = 0.002, d = 1.83), sRPExStep Count (%Δ=66 ± 31%; p = 0.006, d = 2.06), sRPExForce (%Δ=66 ± 29%; p = 0.002, d = 1.91), and miles (%Δ=28 ± 13%; p = 0.019, d = 0.71) compared to minutes (%Δ=20 ± 8%). These findings highlight that only using weekly volume can greatly misrepresent changes in training stress in runners. We therefore encourage coaches and practitioners to consider training monitoring approaches beyond just weekly distance or duration. Simple measures of training load that include duration and sRPE might be sufficient.

INFLUENCE OF HYDRATION STATUS ON RUNNING PERFORMANCE IN HIGH SCHOOL CROSS COUNTRY RUNNERS

Adequate hydration is crucial for athlete's health and performance. Although the impact of hypohydration on professional athletes have been well characterized, there is a dearth of information on the effect of hypohydration on younger populations, such as high school athletes, specifically cross-country runners in a hot and humid environment. PURPOSE: To characterize the effects of hydration status on running performance in high school cross-country runners and determine if a simple hydration plan can improve hydration status. METHODS: 15 high school cross-country runners (9 males, 6 females: 15.5 ± 1.2 yrs) participated in this study. The study took place over a two-week period with baseline testing (V1, V3) and a 5km running performance trials (V2, V4) occurring after school during normal practice hours, with V1 (V3) and V2 (V4) separated by 3 days. A simple hydration strategy of 32oz. of water in the morning and evening preceding the 5km performance trial was implemented to enhance the hydration status of the athletes. Changes in performance between V2 and V4 were determined by 5km completion time, and hydration status was determined by pre- and post-run urine specific gravity using a spectral refractometer. Changes in core temperatures in response to 5km runs were measured on V2 and V4 using core temperature pills. RESULTS: Participants were significantly hypohydrated at rest (USG; V1 = 1.031 ± 0.008, V2 = 1.033 ± 0.006, V3 = 1.030 ± 0.007), but the simple hydration strategy implemented after V3 significantly improved hydration in V4 (resting USG = 1.024 ± 0.008; p<0.001). The average 5km performance times were not significantly different between V2 and V4 (V2:1613.3±224.4 sec, V4:1716.2±176.1 sec), however changes in resting hydration status between V2 and V4 were significantly correlated with improvements in 5km performance time (p=0.02, Pearson’s r=0.63). Changes in core temperature from pre- to post-practice was significantly lower in V2 than V4 (V2:+0.79±0.7 0C, V4:+0.86±1.35 0C; p=0.04). CONCLUSION: High school cross-country runners are hypohydrated, and a simple hydration plan can improve hydration status. Improved hydration was correlated to lower performance times in our cohort of young athletes. The findings support that high school athlete’s hydration status is of concern and should be monitored.

Urogenital Dysfunction Among Female And Male High School Cross-country Runners

While urinary stress incontinence or dysfunctions associated with this condition has been reported in various adult and female sport populations, less is known on their prevalence among distance runners, particularly adolescent female and male distance runners. PURPOSE: To determine the prevalence of urogenital dysfunction (UD) among female and male high school cross-country runners. METHODS: Participants consisted of 104 runners (48 females, 56 males; age: 15.7 ± 1.2y), who competed in interscholastic cross-country in southern California. Each runner completed the Urinary Distress Inventory 6 (UDI-6) to assess urinary dysfunction. The UDI-6 is a six-symptom inventory that allows participants to categorize their symptoms during activities. Runners were identified as having had UD if they reported experiencing any of the six symptoms during the past 3 months. The runners completed the UDI-6 separately for symptoms during running and non-running activities. If a runner reported any of the six symptoms with “somewhat”, “moderately”, or “quite often”, they were considered to have demonstrated UD. Relative risks (RR) and 95% confidence intervals (CIs) were calculated to examine associations between sex and UD. RESULTS: Overall, the number of runners reporting at least one UD symptom was twice as high during non-running activities (56.5%) than running activities (28.3%). Females were more likely than males to report two or more different UD symptoms during non-running activities (39.2% vs. 19.4%; p=0.06) and running activities (13.7% vs. 8.1%; p=0.04). Two female runners reported all 6 UD symptoms during running. Overall, frequent urination and leakage related to feeling of urgency were the most common urogenital dysfunction symptoms reported by the runners; and were reported more commonly during non-running activities compared to running activities (i.e., 45.2% vs. 13.5%, 21.2% vs 7.7%; respectively). Females were twice as likely (RR=2.06, 95% CI: 1.4-3.0; p=0.001) than males to report leakage related to feeling of urgency during non-running activities. CONCLUSIONS: Our findings indicated that urinary dysfunction symptoms are prevalent during non-running and running activities in high school cross-country runners; more so for females.

Relationships Between Sport Specialization and Running-Related Injury Among Competitive High School Cross-Country Runners

BACKGROUND:During the past few decades, the number of participants in high school cross-country has increased. Simultaneously with its popularity has been an increased incidence of running-related injury (RRI). Limited risk factors have been examined in their relationship to RRI in this population. Of these, few studies have reported on the prevalence of sport specialization and its association with RRI among competitive high school cross-country runners.PURPOSE:The purpose of this study was to assess the prevalence of sport specialization and examine its risk association with RRI in competitive high school cross-country runners.METHODS:We prospectively followed 93 runners (35 females, 15.7±1.1y) who competed in the 2018 interscholastic cross-country season in Southern California. At baseline, all runners were injury-free and completed the study questionnaire, which included questions on whether cross-country was their primary sport, the number of months/year spent running-related training, and if they quit another sport(s) to focus on cross-country/track distance running during the past year. High (all 3 factors), moderate (2 of 3 factors) and low (0 or 1 factors) sport specialization was then determined using a widely-utilized scale. Injury occurrence data for all runners was recorded throughout the cross-country season using a standardized injury reporting system. Odds Ratio (OR) estimates and 95% confidence intervals (CIs) were used to determine the association between sport specialization and likelihood of RRI.RESULTS:Of the 93 runners, 15 (16.1%) met criteria for high sport specialization, 49 (52.7%) were classified as moderately specialized, and 29 (31.2%) runners were classified as low sport specializers. The prevalence of high sport specialization was similar between female (17.1%) and male (15.5%) runners (p=0.38). Twenty-six runners (28%) experienced a time loss RRI, with a higher percentage among female runners (37.1%) than males (22.4%) (p=0.16). Although the incidence of injury was greater among high sport specializers (40.0%) than low sport specializers (24.1%), the likelihood of RRI was not statistically significant (OR=2.10, 95% CI: 0.6-8.0; p=0.28). Similar risk associations between high sport specialization and RRI were found between female and male runners.CONCLUSIONS:Based on the existing classification method for sport specialization, these findings indicated that high sports specialization was not common among competitive high school cross-country runners in this study sample. As the incidence of RRI was almost twice as great among high sport specializers, studies assessing larger populations of high school cross-country runners are needed to better evaluate this relationship.

LOWER QUARTER- AND UPPER QUARTER Y BALANCE TESTS AS PREDICTORS OF RUNNING-RELATED INJURIES IN HIGH SCHOOL CROSS-COUNTRY RUNNERS

While cross-country running is a popular interscholastic sport, it also has a high incidence of running-related injuries (RRIs). Recent literature suggests that functional tests may identify athletes at increased risk of injury. The Y-Balance Test (YBT) is an objective measure used to assess functional muscle strength, balance, and expose asymmetries between tested limbs. The purpose of this study was to determine if the YBT could predict RRI in high school cross-country runners. It was hypothesized that an asymmetric right (R)/left (L) YBT reach distance for the lower or upper extremities would be associated with an increased risk of RRI. Prospective observational cohort. One hundred forty-eight athletes (80 girls, 68 boys) who competed in interscholastic cross-country in Southern California during the 2015 season participated in the study. Prior to the cross-country season, the runners completed Lower-Quarter YBT (LQ-YBT) and Upper-Quarter YBT (UQ-YBT) testing to assess lower and upper extremity asymmetry, respectively. The runners were prospectively monitored for RRI occurrence throughout the season using the Daily Injury Report form. Forty-nine runners (33.1%) incurred a RRI during the 2015 season, with the lower leg (shin/calf) and knee the most common RRI sites. Girls had a higher RRI occurrence (38.8%) than boys (26.5%) (p = 0.12). Boys had greater raw scores for LQ-YBT R and L anterior (ANT), posteromedial (PM), posterolateral (PM) and composite reach distances than girls (p<0.05). With the exception of normalized superolateral reach distance, boys had significantly greater scores for raw and normalized R and L UQ-YBT reach distances and raw composite scores than girls (p<0.05). After adjusting for prior RRI, while boy runners with a LQ-YBT PM reach difference ≥4.0 cm were five times more likely to incur a RRI (Adjusted odds ratio [AOR] = 5.05, 95% CI: 1.3-19.8; p = 0.02), girl runners with a UQ-YBT inferolateral (IL) reach difference ≥ 4.0 cm were 75% less likely to incur a RRI (AOR = 0.25, 95% CI: 0.1-0.7; p = 0.005). By lower extremity body region, boy runners with a UQ-YBT superolateral (SL) reach difference ≥ 4.0 cm were seven times more likely to incur a hip/thigh/knee RRI [AOR] = 7.20, 95% CI: 1.1-45.6; p = 0.002). Greater lower extremity (PM) or upper extremity (SL) reach distance asymmetry, as measured by the LQ-YBT or UQ-YBT, respectively, were associated with RRI in boy high school cross-country runners. 2b.

USE OF 2-DIMENSIONAL SAGITTAL KINEMATIC VARIABLES TO ESTIMATE GROUND REACTION FORCE DURING RUNNING

Variations in vertical loading rates have been associated with overuse injuries of the lower extremity; however, they are typically collected using 3-dimensional motion capture systems and in-ground force plates not available to most clinicians because of cost and space constraints. The purpose of this study was to determine if kinetic measures commonly used to describe lower extremity loading characteristics could be estimated from step rate and specific sagittal plane kinematic variables captured using 2-dimensional motion analysis during treadmill running. Observational Study. Ten high school cross-country runners (4 men and 6 women) voluntarily consented to participate in this study. Reflective markers were placed on each lower extremity over multiple anatomical landmarks. Participants were then asked to run on the instrumented treadmill at their preferred running speed. When the participants indicated they were in their typical running pattern, they continued to run at their preferred speed for a minimum of five minutes. After three minutes of running at their preferred running speed, the participant's step rate was counted and after running for four minutes, video and ground reaction force data were recorded for 60 sec. All running motion data were recorded using a single high-speed camera at 240 frames per second and ground reaction force data were sampled at 1000 Hz. Mean kinematic values between the left and right extremities for all 10 participants were not significantly different. Consequently, data for the left and right extremities were grouped for all further analyses. The stepwise forward regression to predict vertical ground reaction force resulted in a five-variable model (step rate and four kinematic variables) with R2 = 0.56. The stepwise forward regression to predict average loading rate also resulted in a five kinematic variable model with R2 = 0.51. Step rate and sagittal plane kinematic variables measured using a simplified 2-dimensional motion analysis approach with a single high-speed camera can provide the clinician with a reasonable estimate of ground reaction force kinetics during treadmill running. 4, Controlled laboratory study.

Factors Associated With Self-Selected Step Rate in High School Cross Country Runners.

Luedke, LE, Heiderscheit, BC, Williams, DSB, and Rauh, MJ. Factors associated with self-selected step rate in high school cross country runners. J Strength Cond Res 35(4): 1141-1148, 2021-Recommendations for step rate, or cadence, during distance running come from varying perspectives including performance, running economy, and injury risk. Studies of adult runners suggest that running experience and leg length may influence step rate, but limited evidence is available on factors that influence adolescent runner step rates. The purpose was to evaluate relationships between running experience, anthropometric factors, and lower extremity muscle strength with self-selected step rate in adolescent runners. Sixty-eight high school cross country runners (47 young women; age 16.2 ± 1.3 years) reported height, body mass, and running experience. Mean step rate was assessed at 3.3 m·s-1 and self-selected (mean 3.8 ± 0.5 m·s-1) speeds. Leg length and peak isometric strength of the hip abductors, knee extensors, and flexors were also measured. Step rates at 3.3 m·s-1 {r (95% confidence interval [CI]) = 0.44 [0.22, 0.61], p < 0.001} and self-selected (r [95% CI] = 0.45 [0.20, 0.66], p < 0.001) speeds were correlated with running experience. Step rates at 3.3 m·s-1 and self-selected speeds were inversely associated with body mass (r [95% CI] = -0.32 [-0.52, -0.09], p = 0.007 and r [95% CI] = -0.34 [-0.53, -0.11], p = 0.005, respectively), height (r [95% CI] = -0.40 [-0.58, -0.18], p = 0.01 and r [95% CI] = -0.32 [-0.52, -0.09], p = 0.008, respectively), and leg length (r [95% CI] = -0.48 [-0.64, -0.27], p < 0.001 and r [95% CI] = -0.35 [-0.52, -0.12], p = 0.004, respectively). No significant relationships were found between isometric strength values and step rate at either speed (p > 0.05). Adolescent runners with greater running experience displayed higher step rates. Hence, the lower step rates in runners with less experience may factor in the higher injury risk previously reported in novice runners. Runners with shorter leg length displayed higher step rates. Step rate recommendations should consider runner experience and anthropometrics.

Lower Extremity Strength and Range of Motion in High School Cross-Country Runners.

Cross-country running is becoming an increasingly popular sport, with a significant participation noted at the high school level. The aim of this study was to compare gender and bilateral hip extension range of motion and hip and knee extension strength of high school cross-country runners. 31 participants volunteered from a local high school cross-country team (16 males and 15 females). The modified Thomas test was utilized to measure hip extension range of motion bilaterally using a digital inclinometer. In order to measure hip and knee isometric strengths, an isokinetic dynamometer was employed. A mixed model approach revealed a statistically significant difference in peak hip extension strength between genders but not the side. Male athletes demonstrated a 29.2 Nm/kg (P < 0.05) greater force production than females during isometric hip extension strength testing. There were no significant differences in peak knee extension isometric strength, hip extension range of motion, and the ratio of peak hip and knee strength between genders and the dominant and nondominant leg. Female cross-country runners should focus on increasing hip extension strength to help maintain hip stability during running. This may be beneficial in decreasing the chances of experiencing patellofemoral pain in long-distance runners.

LEG-LENGTH INEQUALITY AND RUNNING-RELATED INJURY AMONG HIGH SCHOOL RUNNERS

Participation in high school cross-country continues to increase with over 492,000 participants during the 2016-17 cross-country season. Several studies have indicated a high incidence of running-related injuries (RRI) in high school cross-country runners. Risk factors for RRI can be divided between intrinsic and extrinsic risk factors. Intrinsic risk factors such as structural asymmetries have received less attention in recent years. The primary purposes of the current study were to (1) describe the prevalence of leg-length inequality among female and male high school cross-country runners, and (2) to determine whether leg-length inequality was associated with increased RRI in female and male high school cross-country runners. Prospective observational cohort study. Three hundred ninety-three (222 males, 171 females) athletes competing in high school cross-country running were followed, prospectively. The runners' right and left leg-lengths were measured with a standard cloth tape measure in a supine position. Incidence of low back/lower extremity RRI during practices or competitive events was monitored using the Daily Injury Report. A similar percentage of leg-length inequality greater than 0.5 cm was found among female (19.3%) and male (22.1%) runners. No statistically significant associations were found between leg-length inequality and (RRI) for female or male runners, with the exception that after adjusting for BMI, males with a leg-length inequality > 1.5 cm were over seven times more likely to incur a lower leg RRI (Adjusted Odds Ratio = 7.47; 95%CI: 1.5, 36.9; p = 0.01) than males with a leg-length inequality < 0.5 cm. Side of RRI was not associated with side of longer limb length. While leg-length inequality was not associated with RRI, in general, males with a leg-length inequality > 1.5 cm were at greater likelihood of sustaining a lower leg RRI. 2b.

The Impact of Different Cross-Training Modalities on Performance and Injury-Related Variables in High School Cross Country Runners.

Paquette, MR, Peel, SA, Smith, RE, Temme, M, and Dwyer, JN. The impact of different cross-training modalities on performance and injury-related variables in high school cross country runners. J Strength Cond Res 32(6): 1745-1753, 2018-There are many different types of aerobic cross-training modalities currently available. It is important to consider the effects that these different modalities have on running performance and injury risks. The purpose of this study was to compare movement quality, running economy (RE) and performance, injury-related biomechanical variables, and hip muscle strength before and after training with different cross-training modalities in high school runners. Thirty-one high school male runners trained for 4 weeks in 1 of 3 cross-training modalities, in addition to a running-only (n = 9) group, for which training sessions replaced 2 easy runs per week: cycling (CYCLE; n = 6), indoor elliptical (n = 7), and outdoor elliptical bike (EBIKE; n = 9). Functional movement screen (FMS), RE, 3,000-m performance, hip kinematics, and hip muscle strength were assessed. Paired t-tests and Cohen's d effect sizes were used to assess mean differences for each variable before and after training within each group. Elliptical bike training was the only modality that improved FMS scores (d = 1.36) and RE before and after training (d = 0.48). All groups showed improvements in 3,000-m performance, but large effects were found only for the CYCLE (d = 1.50) and EBIKE (d = 1.41) groups. Running-only (d = 1.25), CYCLE (d = 1.17), and EBIKE (d = 0.82) groups showed improvements in maximal hip extensor strength. Outdoor cycling and EBIKE cross-training may be the most effective cross-training modalities to incorporate in early season training to improve running performance in high school runners.

Development of a Sport-specific Curriculum Addressing Self-efficacy to Optimize Carbohydrate and Calorie Intake Among Male and Female High School Cross-country Runners

Design a six-part, sport-specific nutrition curriculum targeted towards high school cross country runners that addresses nutrition knowledge, barriers to change, motivational factors, and self-efficacy through active discussion and reflection, nutrition education and application-based activities.

Effects of Pelvic and Core Strength Training on High School Cross-Country Race Times.

Clark, AW, Goedeke, MK, Cunningham, SR, Rockwell, DE, Lehecka, BJ, Manske, RC, and Smith, BS. Effects of pelvic and core strength training on high school cross-country race times. J Strength Cond Res 31(8): 2289-2295, 2017-There is only limited research examining the effect of pelvic and core strength training on running performance. Pelvic and core muscle fatigue is believed to contribute to excess motion along frontal and transverse planes which decreases efficiency in normal sagittal plane running motions. The purpose of this study was to determine whether adding a 6-week pelvic and core strengthening program resulted in decreased race times in high school cross-country runners. Thirty-five high school cross-country runners (14-19 years old) from 2 high schools were randomly assigned to a strengthening group (experimental) or a nonstrengthening group (control). All participants completed 4 standardized isometric strength tests for hip abductors, adductors, extensors, and core musculature in a test-retest design. The experimental group performed a 6-week pelvic and core strengthening program along with their normal training. Participants in the control group performed their normal training without additional pelvic and core strengthening. Baseline, 3-week, and 6-week race times were collected using a repeated measures design. No significant interaction between experimental and control groups regarding decreasing race times and increasing pelvic and core musculature strength occurred over the 6-week study period. Both groups increased strength and decreased overall race times. Clinically significant findings reveal a 6-week pelvic and core stability strengthening program 3 times a week in addition to coach led team training may help decrease race times.

Fluid Replacement Knowledge and Sources of Hydration in High School Cross-Country Runners

Fluid Replacement Knowledge and Sources of Hydration in High School Cross-Country Runners