Search

Context: High secondary injury rates after orthopedic surgeries have motivated concern toward the construct validity of return-to-sport test batteries, as it is evident that common strength and functional assessments fail to elicit pertinent behaviors like visual search and reactive decision making. This study aimed to establish the test–retest reliability of 2 reactive agility tasks and evaluate the impact of visual perturbation on physical performance. Methods: Fourteen physically active individuals completed 2 agility tasks with reaction time (ie, 4 corner agility), working memory, and pathfinding (ie, color recall) components. Participants completed both tasks 4 times in 2 sessions scheduled 7 days apart. Outcomes included performance metrics of reaction time, time to target, number of targets, and total time assessed with reactive training timing gates. To assess test–retest reliability, we used intraclass correlation coefficients (ICCs), standard error of measurement (SEM), and minimal detectable change (MDC). Stroboscopic goggles induced visual perturbation during the fourth trial of each task. To assess the effect of visual perturbation, we used paired t tests and calculated performance costs. Results: The 4-corner agility task demonstrated excellent reliability with respect to reaction time (ICC3,1 =.907, SEM = 0.13, MDC = 0.35 s); time to light (ICC3,1 =.935, SEM = 0.07, MDC = 0.18 s); and number of lights (ICC3,1 =.800, SEM = 0.24, MDC = 0.66 lights). The color recall task demonstrated good-to-excellent test–retest reliability for time to lights (ICC3,1 =.818–.953, SEM = 0.07–0.27, MDC = 0.19–0.74 s); test time (ICC3,1 =.969, SEM = 5.43, MDC = 15.04 s); and errors (ICC3,1 =.882, SEM = 0.19, MDC = 0.53 errors). Visual perturbation resulted in increased time to target (P =.022–.011), number of targets (P =.039), and total test time (P =.013) representing moderate magnitude degradation of performance (d = 0.55–0.87, performance costs = 5%–12%). Conclusions: Both tasks demonstrated acceptable test–retest reliability. Performance degraded on both tasks with the presence of visual perturbation. These results suggest standardized reactive agility tasks are reliable and could be developed as components of dynamic RTS testing. [ABSTRACT FROM AUTHOR]

Purpose: A decline in youth running was observed at the start of the COVID-19 pandemic. We investigated whether the resumption of organized running after social distancing restrictions changed running habits or injury frequency in adolescent runners. Methods: Adolescents (age = 16.1 [2.1] y) who participated in long-distance running activities completed an online survey in the Spring and Fall of 2020. Participants self-reported average weekly running habits and whether they sustained an injury during the Fall 2020 season. Poisson regression models and 1-way analysis of variance compared running habits while Fisher exact test compared differences in frequencies of injuries during Fall 2020 among season statuses (full, delayed, and canceled). Results: All runners, regardless of season status, increased weekly distance during Fall 2020. Only runners with a full Fall 2020 season ran more times per week and more high-intensity runs per week compared with their Spring 2020 running habits. There were no differences in running volume or running-related injury frequency among Fall 2020 season statuses. Conclusions: There were no significant differences in running-related injury (RRI) frequency among runners, regardless of season status, following the resumption of cross-country. Health care providers may need to prepare for runners to increase running volume and intensity following the resumption of organized team activities. [ABSTRACT FROM AUTHOR]

Context: Arthrogenic muscle inhibition (AMI) is a common neurophysiological response to joint injury. While athletic trainers (ATs) are constantly treating patients with AMI, it is unclear how clinicians are using the available evidence to treat the condition. Objective: To investigate ATs' general knowledge, clinical practice, and barriers for treating AMI. Methods: A cross-sectional web-based survey was utilized. The survey was distributed to a random sample of 3000 ATs from the National Athletic Trainers' Association and through social media. 143 board certified ATs (age: 34.6 [10.3] y; experience: 11.7 [9.8] y) from various clinical settings and educational backgrounds were included in the analysis. Results: One hundred one respondents were able to correctly identify the definition of AMI. The majority of these respondents correctly reported that joint effusion (n = 95, 94.1%) and abnormal activity from joint receptors (n = 91, 90.1%) resulted in AMI. Of the 101 respondents, only 58 (57.4%) reported using disinhibitory interventions to treat AMI. The most frequently used evidence supported interventions were transcutaneous electrical nerve stimulation (n = 38,65.5%), neuromuscular electrical stimulation (n = 33,56.9%), and focal joint cooling (n = 25, 43.1 %). The interventions used correctly most often based on current evidence were neuromuscular electrical stimulation (n = 29/33, 87.9%) and transcutaneous electrical nerve stimulation (n = 26/38, 68.4%). Overall, difficulty quantifying AMI (n = 62, 61.24%) and lack of education (n = 71, 76.2%) were most frequently perceived as barriers. Respondents that did not use disinhibitory interventions perceived lack of experience treating AMI, understanding the terminology, and access to therapeutic modalities more often than the respondents that reported using disinhibitory interventions. Conclusion: Further education about concepts and treatment about AMI is warranted for ATs. Continued understanding of ATs' clinical practice in regard to AMI may help identify gaps in athletic training clinical education. [ABSTRACT FROM AUTHOR]

Purpose: 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. Methods: 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. Results: 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 −0.8 km (95% = –6.3 to +4.8 km) for distance, −4.5 minutes (95% = −27.8 to +33.2 min) for moving duration, and 2.7 minutes (95% = –27.8 min to +33.2 min) for elapsed duration. Conclusions: 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. [ABSTRACT FROM AUTHOR]

Differences in running biomechanics have been reported in adult long-distance runners when running in motion control or neutral shoes. The influence of growth and coordination refinement during puberty limits the generalisability of adult research to adolescents and it is unknown if biomechanics differ between adolescent who run in different types of shoes. The purpose of our study was to compare lower extremity kinematics and ground reaction forces between adolescents running in motion control or neutral shoes. We matched 18 adolescent long-distance runners who ran in motion control shoes with 18 adolescent long-distance runners who ran in neutral shoes according to running speed, sex, and physical maturation. We collected three-dimensional kinematic and ground reaction force data during overground running and performed statistical parametric mapping to compare joint angle and ground reaction force waveforms between the motion control and neutral shoe groups. We found no significant differences for hip, knee, or ankle joint angles (average differences <2°) or ground reaction forces (average differences <0.05 N/kg) between runners who ran in motion control or neutral shoes. Lower extremity kinematics and ground reaction forces were similar between adolescents who ran in motion control or neutral shoes. [ABSTRACT FROM AUTHOR]

Context: Lumbopelvic-hip complex (LPHC) exercises are used to increase stabilization within the human body. Torso-elevated side support (TESS), foot-elevated side support (FESS), prone bridge plank (PBP), and V-sit are common LPHC exercises. Objective: To evaluate muscle activation in the shoulder girdle and LPHC during 4 LPHC exercises and evaluate the reasoning for termination. Study Design: Cross-sectional study. Setting: Laboratory. Patients or Other Participants: Seventeen healthy participants (12 males and 5 females; age: 21.47 [3.16] y, height: 179.73 [8.92] cm, mass: 76.89 [11.17] kg). Main Outcome Measures: Participants completed 2 repetitions of the TESS, FESS, PBP, and V-sit until failure. Surface electromyography of the middle deltoid, latissimus dorsi, middle trapezius, rectus abdominis, erector spinae, external oblique, and gluteus medius were recorded and normalized to maximum voluntary isometric contraction (MVIC). The duration of exercise and subjective reasoning for termination of exercise was completed following the 4 tasks. Results: The TESS and PBP had significantly greater middle deltoid muscle activation (TESS: 55.66% [24.45%] MVIC and PBP: 42.63% [18.25%] MVIC) compared with the FESS (10.10% [10.04%] MVIC) and V-sit (2.21% [1.94%] MVIC), P < .05. The TESS produced significantly greater external oblique activity (78.13% [32.32%] MVIC) than the PBP (54.99% [19.54%] MVIC), P < .05. Due to shoulder fatigue and pain, 41.1% and 17.0% of participants terminated the TESS, respectively. The PBP was terminated due to abdominal fatigue (41.1%) and upper-extremity fatigue (47.0%). Conclusions: The V-sit resulted in isolated activity of the abdominal portion of the LPHC. The FESS had increased global co-contraction of the LPHC compared with the TESS. The PBP and TESS had significant muscle activation in the upper-extremity. [ABSTRACT FROM AUTHOR]

Context: Hip muscle strength has previously been evaluated in various sagittal plane testing positions. Altering the testing position appears to have an influence on hip muscle torque during hip extension, abduction, and external rotation. However, it is unknown how altering the testing position influences hip muscle activity during these commonly performed assessments. Objectives: To evaluate how hip sagittal plane position influences hip muscle activation and torque output. Study Design: Cross-sectional. Setting: Laboratory. Patients or Other Participants: A total of 22 healthy females (age = 22.1 [1.4] y; mass = 63.4 [11.3] kg; height = 168.4 [6.2] cm) were recruited. Intervention: None. Main Outcome Measures: Participants completed isometric contractions with surface electromyography on the superior and inferior gluteus maximus; anterior, middle, and posterior gluteus medius; biceps femoris, semitendinosus, adductor longus, and tensor fascia latae. Extension and external rotation were tested in 0°, 45°, and 90° of hip flexion and abduction was tested in −5°, 0°, and 45° of hip flexion. Repeated-measures analysis of variances were used for statistical analysis (P ≤.01). Results: Activation of gluteal (P <.007), semitendinosus (P =.002), and adductor longus (P =.001) muscles were lesser for extension at 90° versus less flexed positions. Adductor longus activity was greatest during 90° of hip flexion for external rotation torque testing (P <.001). Tensor fascia latae (P <.001) and gluteus maximus (P <.001) activities were greater in 45° of hip flexion. Significant differences in extension (P <.001) and abduction (P <.001) torque were found among positions. Conclusions: Position when assessing hip extension and abduction torque has an influence on both muscle activity and torque output but only muscle activity for hip external rotation torque. Clinicians should be aware of the influence of position on hip extension, abduction, and external rotation muscle testing and select a position most in line with their clinical goals. [ABSTRACT FROM AUTHOR]