Plank Times and Lower Extremity Overuse Injury in Collegiate Track-and-Field and Cross Country Athletes.

Trunk muscle endurance has been theorized to play a role in running kinematics and lower extremity injury. However, the evidence examining the relationships between static trunk endurance tests, such as plank tests, and lower extremity injury in athletes is conflicting. The purpose of this study was to assess if collegiate cross country and track-and-field athletes with shorter pre-season prone and side plank hold times would have a higher incidence of lower extremity time-loss overuse injury during their competitive sport seasons. During the first week of their competitive season, 75 NCAA Division III uninjured collegiate cross country and track-and-field athletes (52% female; mean age 20.0 ± 1.3 years) performed three trunk endurance plank tests. Hold times for prone plank (PP), right-side plank (RSP) and left-side plank (LSP) were recorded in seconds. Athletes were followed prospectively during the season for lower extremity overuse injury that resulted in limited or missed practices or competitions. Among the athletes, 25 (33.3%) experienced a lower extremity overuse injury. There were no statistically significant mean differences or associations found between PP, RSP or LSP plank test hold times (seconds) and occurrence of lower extremity overuse injury. In isolation, plank hold times appear to have limited utility as a screening test in collegiate track-and-field and cross country athletes.

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

ABSTRACT: 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.

Y-Balance Test Performance Does Not Determine Non-Contact Lower Quadrant Injury in Collegiate American Football Players.

Collegiate American football has a high rate of injury. The Lower Quarter Y-Balance Test (YBT-LQ), a dynamic assessment of lower extremity strength, mobility, and balance, has been purported to identify athletes at risk for injury in different sports including football. Previous studies examining the association between YBT-LQ and injury have reported varied findings; therefore, the purpose of this study was to assess if preseason YBT-LQ performance predicted whether football players would sustain a non-contact lower extremity or low back (lower quarter (LQ)) injury during the season. Fifty-nine male collegiate American football players (age 20.8 ± 1.3 y, height 1.8 ± 0.1 m, body mass 94.6 ± 14.2 kg) completed a survey of training and injury history and had their YBT-LQ performance assessed at the start of the season. Athletic training staff tracked the occurrence of non-contact LQ injuries during the season. There were no significant relationships found between preseason YBT-LQ values and incidence of non-contact LQ injury in this population of collegiate American football players. This study is consistent with recent reports that have not found a significant association between preseason YBT-LQ values and LQ injury. These results suggest that, in isolation, the YBT-LQ may have limited utility as a screening test for non-contact injury in collegiate football players.

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.

Influence of Step Rate on Shin Injury and Anterior Knee Pain in High School Runners.

PURPOSE: High school cross-country runners have a high incidence of injury, particularly at the shin and knee. An increased step rate during running has been shown to reduce impact forces and loading of the lower extremity joints. The purpose of this prospective study was to examine step rate as a risk factor for injury occurrence. MATERIALS AND METHODS: Running step rates of 68 healthy high school cross-country runners (47 females; 21 males; mean age 16.2 ± 1.3 yr) were assessed at a fixed speed (3.3 ± 0.0 m·s) and self-selected speed (mean, 3.8 ± 0.5 m·s). Runners were prospectively followed during the interscholastic season to determine athletic exposures, occurrences of shin injury and anterior knee pain (AKP), and days lost to injury. RESULTS: During the season, 19.1% of runners experienced a shin injury and 4.4% experienced AKP. Most injuries (63.6%) were classified as minor (1-7 d lost). At the fixed speed, runners in the lowest tertile of step rate (≤164 steps per minute) were more likely (odds ratio, 6.67; 95% confidence interval, 1.2-36.7; P = 0.03) to experience a shin injury compared with runners in the highest tertile (≥174 steps per minute). Similarly, for self-selected speed, runners in the lowest tertile (≤166 steps per minute) (odds ratio, 5.85; 95% confidence interval, 1.1-32.1; P < 0.04) were more likely to experience a shin injury than runners in the highest tertile (≥178 steps per minute). AKP incidence was not significantly influenced by step rate. CONCLUSION: A lower running step rate was associated with a greater likelihood of shin injury at both self-selected and fixed running speeds. Future studies evaluating whether increasing running step rate reduces shin injury risk and time lost during a high school cross-country season should be considered.

ASSOCIATION OF ISOMETRIC STRENGTH OF HIP AND KNEE MUSCLES WITH INJURY RISK IN HIGH SCHOOL CROSS COUNTRY RUNNERS.

BACKGROUND: High school cross country runners have a high incidence of overuse injuries, particularly to the knee and shin. As lower extremity strength is modifiable, identification of strength attributes that contribute to anterior knee pain (AKP) and shin injuries may influence prevention and management of these injuries. PURPOSE: To determine if a relationship existed between isometric hip abductor, knee extensor and flexor strength and the incidence of AKP and shin injury in high school cross country runners. MATERIALS/METHODS: Sixty-eight high school cross country runners (47 girls, 21 boys) participated in the study. Isometric strength tests of hip abductors, knee extensors and flexors were performed with a handheld dynamometer. Runners were prospectively followed during the 2014 interscholastic cross country season for occurrences of AKP and shin injury. Bivariate logistic regression was used to examine risk relationships between strength values and occurrence of AKP and shin injury. RESULTS: During the season, three (4.4%) runners experienced AKP and 13 (19.1%) runners incurred a shin injury. Runners in the tertiles indicating weakest hip abductor (chi-square = 6.140; p=0.046), knee extensor (chi-square = 6.562; p=0.038), and knee flexor (chi-square = 6.140; p=0.046) muscle strength had a significantly higher incidence of AKP. Hip and knee muscle strength was not significantly associated with shin injury. CONCLUSIONS: High school cross country runners with weaker hip abductor, knee extensor and flexor muscle strength had a higher incidence of AKP. Increasing hip and knee muscle strength may reduce the likelihood of AKP in high school cross country runners. LEVEL OF EVIDENCE: 2b.