PREDICTORS OF PELVIC ACCELERATION DURING TREADMILL RUNNING AT DIFFERENT STRIDE FREQUENCIES

The aim of this study was to examine predictors of peak vertical and anteroposterior pelvic acceleration during treadmill running. Participants ran at 9 km∙h-1 at their preferred stride frequency and at ± 5% of their preferred stride frequency. Coordinate and acceleration data were collected using a motion capture system and inertial measurement units. Linear mixed models showed that for every one standard deviation increase in the anteroposterior displacement from knee to ankle at initial contact, vertical pelvic acceleration increased by 2.18 m∙s-2 (p = 0.046). Additionally, for every one standard deviation increase in stride frequency, peak anteroposterior pelvic acceleration increased by 0.68 m∙s-2 (p = 0.035). Runners who suffer from injuries or pain at the pelvis may benefit from decreasing the anteroposterior displacement from their knee to their ankle at initial contact and reducing their stride frequency

Is your system fit for purpose? Female athlete health considerations for rugby injury and illness surveillance systems

This review discusses female-specific health considerations in injury and illness surveillance and provides rugby-specific recommendations for future surveillance. Identifying priority injury and illness problems by determining those problems with the highest rates within women's rugby may highlight different priorities than sex comparisons between men's and women's rugby. Whilst sports exposure is the primary risk for health problems in sports injury and illness surveillance, female athletes have health domains that should also be considered. Alongside female athlete health domains, studies investigating rugby injuries and illnesses highlight the need to broaden the health problem definition typically used in rugby injury and illness surveillance. Using a non-time-loss health problem definition, recording female-specific population characteristics, embedding female athlete health domains and having up-to-date injury and illness coding systems should be prioritized within surveillance systems to begin to shed light on potential interactions between sports exposure, health domains and, injuries and illnesses. We call for a collaborative approach across women's rugby to facilitate large injury and illness datasets to be generated and enable granular level categorization and analysis, which may be necessary for certain female athlete health domains. Applying these recommendations will ensure injury and illness surveillance systems improve risk identification and better inform injury and illness prevention strategies in women's rugby

Wrist-worn Accelerometry for Runners: Objective Quantification of Training Load.

PURPOSE: This study aimed to apply open-source analysis code to raw habitual physical activity data from wrist-worn monitors to: 1) objectively, unobtrusively, and accurately discriminate between "running" and "nonrunning" days; and 2) develop and compare simple accelerometer-derived metrics of external training load with existing self-report measures. METHODS: Seven-day wrist-worn accelerometer (GENEActiv; Activinsights Ltd, Kimbolton, UK) data obtained from 35 experienced runners (age, 41.9 ± 11.4 yr; height, 1.72 ± 0.08 m; mass, 68.5 ± 9.7 kg; body mass index, 23.2 ± 2.2 kg·m; 19 [54%] women) every other week over 9 to 18 wk were date-matched with self-reported training log data. Receiver operating characteristic analyses were applied to accelerometer metrics ("Average Acceleration," "Most Active-30mins," "Mins≥400 mg") to discriminate between "running" and "nonrunning" days and cross-validated (leave one out cross-validation). Variance explained in training log criterion metrics (miles, duration, training load) by accelerometer metrics (Mins≥400 mg, "workload (WL) 400-4000 mg") was examined using linear regression with leave one out cross-validation. RESULTS: Most Active-30mins and Mins≥400 mg had >94% accuracy for correctly classifying "running" and "nonrunning" days, with validation indicating robustness. Variance explained in miles, duration, and training load by Mins≥400 mg (67%-76%) and WL400-4000 mg (55%-69%) was high, with validation indicating robustness. CONCLUSIONS: Wrist-worn accelerometer metrics can be used to objectively, unobtrusively, and accurately identify running training days in runners, reducing the need for training logs or user input in future prospective research or commercial activity tracking. The high percentage of variance explained in existing self-reported measures of training load by simple, accelerometer-derived metrics of external training load supports the future use of accelerometry for prospective, preventative, and prescriptive monitoring purposes in runners

An International Collaboration to Promote Inquiry-based Learning in Undergraduate Engineering Classrooms

Abstract Theorists such as Bransford et al. argue that twenty-first century educators need to teach students to do more than simply remember and repeat information. Engineering educators Prince and Felder critique traditional methods of teaching in which instructors focus on mathematics and theory, but fail to convey practical applications of that knowledge. They advocate moving students to a higher level of learning -past the stage of memorizing and reciting data -to more sophisticated methods of analysis, synthesis, and application of knowledge. To enact such transformations, Prince and Felder recommend "inductive teaching methods," including "inquiry-based learning," in which students learn through engaging with challenges and a series of questions. The purpose of this paper is to describe specific techniques of "inquiry-based learning" employed by three instructors in Engineering schools, one in Europe and two in the USA. The paper provides examples of inquiry-based learning activities from each of the authors. The paper then discusses the cross-pollination of ideas and describes how the authors have shared inquiry-based teaching strategies and collaborated to develop new and relevant assignments and approaches to teaching

The influence of biological maturity on dynamic force–time variables and vaulting performance in young female gymnasts

Purpose: This cross-sectional study investigated dynamic force–time variables and vaulting performance in young female gymnasts of different maturity status. Methods: 120 gymnasts aged 5–14 years were sub-divided into maturity groupings using percent of predicted adult height (%PAH) attained. Participants performed three jumping protocols, the squat jump (SJ), countermovement jump (CMJ) and drop jump (DJ), before completing straight jump vaults that were recorded using two-dimensional video. Results: Jumping performance improved with biological maturity evidenced by the most mature gymnasts’ producing significantly more absolute force (P \u3c 0.05; all d \u3e 0.78), impulse (P \u3c 0.05; all d \u3e 0.75) and power (P \u3c 0.05; all d \u3e 0.91) than the least mature group, resulting in the greater jump heights (P \u3c 0.05; all d \u3e 0.70). While, no significant differences were observed in relative peak force across multiple tests, measures of relative peak power did significantly increase with maturity. Based upon regression analyses, maturation was found to influence vertical take-off velocity during vaulting, explaining 41% of the variance in each jumping protocol. Across all tests, the DJ was found to have the highest predictive ability of vaulting vertical take-off velocity, explaining 55% of the total variance. Conclusion: Biological maturation impacts jump height and underpinning mechanical variables in young female gymnasts. Vaulting vertical take-off velocity appears to be influenced by maturation and various dynamic force–time variables, particularly those during DJ, which had the highest explained total variance

Effects of a 12-Week Training Program on Isometric and Dynamic Force-Time Characteristics in Pre– and Post–Peak Height Velocity Male Athletes

Literature shows that training children and adolescents can enhance strength and power irrespective of their stage of development; however, the development of the kinetic variables that underpin strength and power performance are typically unreported in youth training studies. Twenty-four pre– and 14 post–peak height velocity (PHV) male athletes were divided into maturity-specific experimental (EXP) and control groups (CON), with the EXP groups completing a twice-weekly, 12-week training program. Force-time characteristics during the isometric midthigh pull (IMTP), countermovement jump, and squat jump tests were quantified at both baseline and after the completion of the 12-week program. Alpha level was set at p 0.05). Analysis of IMTP data revealed that only the post-PHV EXP group significantly increased absolute isometric peak force (PFabs) and peak rate of force development within the IMTP after training. Both EXP groups displayed significant increases in isometric PF at time epochs 0–90, 0–150, 0–200, and 0–250 ms. Data from the dynamic tests indicated that the pre-PHV EXP cohort improved concentric qualities as reflected by increased squat jump height and countermovement jump concentric power. There were no significant changes for any variables across all tests within either CON group (p > 0.05). Maturity-related differences in response to short-term training affects the kinetic variables associated with strength and power performance, but not movement competency in young male athletes

Movement competency and measures of isometric and dynamic strength and power in boys of different maturity status

An understanding of how movement competency, strength, and power interacts with natural growth and maturation is required in order to determine meaningful changes with developing athletes. Isometric and dynamic testing in youth athletes provide insight into the natural development of the force‐velocity (F‐V) spectrum. Two‐hundred and six young male athletes, aged 9‐17 years of age were grouped according to stage of maturation based on their maturity offset which was determined as number of years from peak height velocity (PHV). All participants performed the back‐squat assessment (BSA), isometric mid‐thigh pull (IMTP), countermovement jump (CMJ) and squat jump (SJ) tests. Absolute and scaled force‐time variables were collected from the IMTP, CMJ, and SJ. No significant differences were observed between maturational groups for squat movement competency (p > 0.05). One‐way ANOVA with Bonferroni post‐hoc analysis revealed that increasing maturity led to significant, moderate to large increases in allometrically scaled peak force (PFallo) for all tests (p < 0.05). Multiple stepwise linear regression models revealed IMTP PFallo significantly predicted 34.8% and 41.3% of variance in SJ and CMJ jump height, respectively (p < 0.05). Natural growth and maturation induces positive adaptations to movement competency as well as isometric and dynamic strength and power. Trends from the IMTP, SJ, and CMJ tests indicate the largest differences in strength and power may occur around the adolescent growth spurt despite the large variation in rates of change within the circa‐PHV group

On average, a professional rugby union player is more likely than not to sustain a concussion after 25 matches

Objectives To investigate concussion injury rates, the likelihood of sustaining concussion relative to the number of rugby union matches and the risk of subsequent injury following concussion. Methods A four-season (2012/2013–2015/2016) prospective cohort study of injuries in professional level (club and international) rugby union. Incidence (injuries/1000 player-match-hours), severity (days lost per injury) and number of professional matches conferring a large risk of concussion were determined. The risk of injury following concussion was assessed using a survival model. Results Concussion incidence increased from 7.9 (95% CI 5.1 to 11.7) to 21.5 injuries/1000 player-match-hours (95% CI 16.4 to 27.6) over the four seasons for combined club and international rugby union. Concussion severity was unchanged over time (median: 9 days). Players were at a greater risk of sustaining a concussion than not after an exposure of 25 matches (95% CI 19 to 32). Injury risk (any injury) was 38% greater (HR 1.38; 95% CI 1.21 to 1.56) following concussion than after a non-concussive injury. Injuries to the head and neck (HR 1.34; 95% CI 1.06 to 1.70), upper limb (HR 1.59; 95% CI 1.19 to 2.12), pelvic region (HR 2.07; 95% CI 1.18 to 3.65) and the lower limb (HR 1.60; 95% CI 1.21 to 2.10) were more likely following concussion than after a non-concussive injury. Conclusion Concussion incidence increased, while severity remained unchanged, during the 4 years of this study. Playing more than 25 matches in the 2015/2016 season meant that sustaining concussion was more likely than not sustaining concussion. The 38% greater injury risk after concussive injury (compared with non-concussive injury) suggests return to play protocols warrant investigation

The relationship between running biomechanics and running economy: a systematic review and meta-analysis of observational studies

Running biomechanics is considered an important determinant of running economy (RE). However, studies examining associations between running biomechanics and RE report inconsistent findings. The aim of this systematic review was to determine associations between running biomechanics and RE and explore potential causes of inconsistency. Three databases were searched and monitored up to April 2023. Observational studies were included if they (i) examined associations between running biomechanics and RE, or (ii) compared running biomechanics between groups differing in RE, or (iii) compared RE between groups differing in running biomechanics during level, constant-speed, and submaximal running in healthy humans (18-65 years). Risk of bias was assessed using a modified tool for observational studies and considered in the results interpretation using GRADE. Meta-analyses were performed when two or more studies reported on the same outcome. Meta-regressions were used to explore heterogeneity with speed, coefficient of variation of height, mass, and age as continuous outcomes, and standardization of running shoes, oxygen versus energetic cost, and correction for resting oxygen or energy cost as categorical outcomes. Fifty-one studies (n = 1115 participants) were included. Most spatiotemporal outcomes showed trivial and non-significant associations with RE: contact time r = - 0.02 (95% confidence interval [CI] - 0.15 to 0.12); flight time r = 0.11 (- 0.09 to 0.32); stride time r = 0.01 (- 0.8 to 0.50); duty factor r = - 0.06 (- 0.18 to 0.06); stride length r = 0.12 (- 0.15 to 0.38), and swing time r = 0.12 (- 0.13 to 0.36). A higher cadence showed a small significant association with a lower oxygen/energy cost (r = - 0.20 [- 0.35 to - 0.05]). A smaller vertical displacement and higher vertical and leg stiffness showed significant moderate associations with lower oxygen/energy cost (r = 0.35, - 0.31, - 0.28, respectively). Ankle, knee, and hip angles at initial contact, midstance or toe-off as well as their range of motion, peak vertical ground reaction force, mechanical work variables, and electromyographic activation were not significantly associated with RE, although potentially relevant trends were observed for some outcomes. Running biomechanics can explain 4-12% of the between-individual variation in RE when considered in isolation, with this magnitude potentially increasing when combining different variables. Implications for athletes, coaches, wearable technology, and researchers are discussed in the review

Utility of Kinetic and Kinematic Jumping and Landing Variables as Predictors of Injury Risk: A Systematic Review

Purpose: Jump-landing assessments provide a means to quantify an individual’s ability to attenuate ground reaction forces, generate lower limb explosive power and maintain joint alignment. In order to identify risk factors that can be targeted through appropriate training interventions, it is necessary to establish which (scalar) objective kinetic, kinematic, and performance measures are most associated with lower-extremity injury, Methods: Online searches of MEDLINE, SCOPUS, EBSCOHost, SPORTDiscus and PubMed databases were completed for all articles published before March 2020 in accordance with PRISMA guidelines. Results: 40 articles investigating nine jump-landing assessments were included in this review. 79% of studies using drop jump (n =14) observed an association with future injury, while only 8% of countermovement jump studies (n = 13) observed an association with injury risk. 57% of studies using unilateral assessments found associations with risk of injury (n = 14). Studies using performance measures (jump height/ distance) as outcome measure were only associated with injury risk in 30% of cases. However, those using kinetic and/or kinematic analyses (knee abduction moment, knee valgus angle, knee separation distance, peak ground reaction force) found associations with injury in 89% of studies. Conclusion: The landing element of jump-landing assessments appears to be superior for identifying individuals at greater risk of injury; likely due to a closer representation of the injury mechanism. Consequently, jump-landing assessments that involve attenuation of impact forces such as the drop jump appear most suited for this purpose but should involve assessment of frontal plane knee motion and ground reaction forces