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Belief Factors Influencing Pre-Service Teacher Responsiveness to Trans* & Gender Non-Conforming Youth
Full text linkThe purpose of this research was to investigate person-centered belief factors that influence pre-service teacher (PST) responsiveness to transgender and gender non-conforming (TGNC) youth. This study examined the influence of PSTs’ ally-identity, attitudes, and self efficacy on their responses to vignettes of TGNC victimization and found the belief factors accounted for 45.1% of the variance. Ally-identity and self-efficacy were significant predictors of PST responsiveness to TGNC victimization. Likewise, this study sought to extend previous research (Zack et al., 2010) that proposed four different categories, or archetypes, for understanding student teachers’ responses to TGNC victimization – Avoiders, Hesitators, Confronters, and Integrators. Participants’ (77.3%) responses to TGNC victimization vignettes indicated that they were likely to either take affirming action in situations where gender identity and transgender status is relevant (Confronters) or would act and advocate for systemic remedies (Integrators). Given the differences between archetypes and the effect sizes, this study highlights opportunities for intervention regarding self-efficacy and ally-identity during teacher preparation programs, with the goal of shaping PSTs into highly responsive educators
ONE-LEG BACKWARD HOPPING IMPOSES GREATER KNEE DEMANDS COMPARED TO VERTICAL HOPPING IN ACLR PATIENTS
No full textIn the clinical setting, knee functionality following an anterior cruciate ligament reconstruction (ACLR) is commonly evaluated using one-leg hopping performances, such as forward hopping for distance and vertical hopping for height. One-leg vertical hopping was considered to be a better metric to evaluate the knee compared to forward hopping due to greater knee emphasis. Recently, one-leg backward hopping was found to impose the greatest knee demands compared to forward and vertical hopping. PURPOSE: Determine knee mechanics during one-leg vertical and backward hopping in ACLR patients in comparison to healthy controls. METHODS: Fifteen female participants were recruited with eight unilateral ACLR patients (33.8 ± 22.1 months after ACLR, age 20.2 ± 1.5 yr, height 1.6 ± 0.1 m, and mass 69.2 ± 14.3 kg) and seven healthy controls (age 19.6 ± 1.3 yr, height 1.7 ± 0.0 m, and mass 67.1 ± 16.0 kg). Participants performed one-leg vertical hopping for height and backward hopping for distance on each leg with motion and force data collected. The hopping performance, peak knee flexion angle, peak knee extension moment, and peak knee power were calculated during jumping. Results were reported for each leg in ACLR patients, and the average of both legs was in healthy controls. RESULTS: One-leg backward hopping showed greater peak knee flexion angle, knee extension moment, and knee power compared to vertical hopping, regardless of legs and groups (Table 1). The decreasing order of knee variables were healthy controls, uninjured knee, and injured knee in one-leg backward hopping. The uninjured knee showed greater knee measurements than the injured knee in one-leg vertical and backward hopping. CONCLUSION: One-leg backward hopping imposes greater knee demands than vertical hopping in ACLR patients and healthy controls, indicating a more challenging task to assess knee function in individuals after ACLR
DROP JUMP FORCE-TIME CHARACTERISTICS WITHIN NCAA DIVISION-I SPRINTERS
No full textGenerating force and being technically proficient are key components when sprinting maximally. For short distances like 60-meter, 100-meter, and 200-meter races, more information which examines lower-body muscular power within collegiate track and field populations is needed. PURPOSE: The purpose of this study was to analyze specific drop jump (DJ) force-time characteristics of collegiate sprinters. METHODS: 10 (male; n=5 [1 Olympian], height; 1.78-1.82m, weight; 67.5-79.8kg, and female; n=5, height; 1.6-1.73m, weight; 57.2-66.8kg) NCAA Division-I sprinters participated in this study. Average braking forces (ABF), average propulsive forces (APF), net impulse ratio (NIR) and DJ height were collected by using a uniaxial dual force plate system sampling at 1,000 Hz. Athletes performed three trials separated by 20-seconds from a 12-inch plyometric box with hands remaining on hips then rapidly redirecting to a maximal jump. Athletes were grouped by sex to compare performance. Descriptive statistics, Spearman’s rank correlation coefficient, and independent samples t-tests were calculated to analyze differences between groups. RESULTS: Significant strong positive correlations were observed between ABF (r = 0.792; p \u3c 0.001), APF (r = 0.883; p \u3c 0.001), NIR (r = 0.998; p \u3c 0.001) and DJ height. Significant differences were observed between sexes for measures of ABF (p = 0.046) and APF (p = 0.002). However, no significant differences were observed for measures of DJ height or NIR. CONCLUSIONS: To conclude, the primary purpose of this investigation was to analyze specific drop jump (DJ) force-time characteristics of collegiate sprinters. Significant relationships between dynamic eccentric and concentric force production, transference capabilities, and DJ height were observed irrespective of sex. Additionally, no significant differences between sexes were observed for measures of jump height or NIR. Based on the findings of the current study, NCAA Division-I sprinters possess optimal force production and transference capabilities irrespective of sex. Therefore, dynamic exercises that emphasize the development and transference of absolute forces should be implemented within this population as they are strongly related to DJ ability, which may positively contribute to sprinting ability
UPPER EXTREMITY MUSCULAR PERFORMANCE AND PERCEIVED PERFORMANCE READINESS IN COLLEGIATE ATHLETES ACROSS THE MENSTRUAL CYCLE
No full textPURPOSE: Female sex hormone (estrogen and progesterone) concentrations fluctuate throughout phases of the menstrual cycle, which may impact muscular strength and endurance. We assessed muscular strength and endurance, and perceived fatigue, motivation, strength, and energy at different phases of the menstrual cycle. METHODS: Collegiate softball players participated in this study (n = 11; 19 ± 1 yr). During the initial visit, participants’ height, weight, body composition (InBody 770), resting metabolic rate (Parvo TrueOne 2400), and cycle history were determined (FLO app). Participants returned during their projected early-follicular (EF), ovulatory (OV), and mid-luteal (ML) phases for performance testing. During EF, OV, and ML, participants reported their perceived fatigue, motivation, strength, and energy. Following a standardized warm-up, participants performed 1RM bench press testing. After establishing their 1RM, participants then performed 70% of their bench press 1RM for as many repetitions as possible (reps to failure or RTF). Differences in the data collected between EF, OV, and ML were determined using a one-way, repeated measures MANOVA followed by Bonferroni post-hoc testing. All data are reported as mean ± standard deviation, and a was set at p ≤ .05. RESULTS: Perceived motivation (3.2% \u3e EF, 40.3% \u3e OV), strength (12.4% \u3e EF, 14.2% \u3e OV), and energy (1.7% \u3e EF, 23.5% \u3e OV) peaked during ML, though these results were not significant (p \u3e .05). Perceived fatigue was also lower during ML compared to EF (-17.8%) and OV (19.8), though this was not significant (p \u3e .05). Bench press 1RM peaked during EF (51.1 ± 6.2 kg) compared to OV (47.7 ± 0.0 kg) and ML (50 6.8 kg). Bench press RTF (repetitions) peaked during OV (12.7 ± 2.5) compared to EF (10.4 ± 2.2) and ML (11.7 3.8). CONCLUSION: Participants’ self-reported motivation, strength, and energy was highest during ML, while self-reported fatigue was also lowest during ML. Despite this consistency, bench press 1RM and RTF peaked during EF and OV, respectively. Though no statistical significance was found, it appears there is a disconnect between perceived readiness for performance testing and the actual performance testing. Further data collection will clarify the potential differences in these characteristics in female athletes throughout the menstrual cycle
Force and Gait Mechanics at Reduced Body Weight on a Lower Body Positive Pressure Treadmill
Full text linkInternational Journal of Exercise Science 18(7): 239-250, 2025. Lower body positive pressure treadmills (LBPPT) have gained increasing attention due to their potential applications in sports training, rehabilitation, and biomechanics research. However, there is limited understanding of how differing body weight percentages influence gait and force production. This study aimed to investigate the relationship between force and gait parameters at different body weight percentages on a LBPPT. Twenty-seven healthy participants completed a series of walking, jogging, and running trials at three different body weight conditions: 100%, 90%, and 75%. Gait parameters, including cadence, stride length, stance time, and ground reaction force, were measured using the Digitsole Pro foot insoles and analyzed across the different conditions. Repeated measures ANOVA and pairwise comparisons were used to examine the effects of body weight percentage on the gait parameters. The results showed significant effects of BW on cadence, stride length, stance time, and impact force during running condition (p \u3c 0.001). Jogging condition was significantly different across all % BW for all variables except ground reaction force (GRF). For walking, the only significant differences presented were for stride length on the right limb between 100% and 90% BW (p = 0.004) and 100% and 75% BW (p = 0.04) and time in stance on the left and right (p \u3c 0.05). Pairwise comparisons revealed significant differences between the 100%, 90%, and 75% BW conditions for most gait parameters during jogging and running. These findings suggest that lower body weight percentages substantially influence gait mechanics and force production, especially as speed increases
Sex-Specific Responses of Heat Acclimation on Running Performance in Cool Environmental Conditions
Full text linkTraining and competing in the heat negatively impact athlete performance and health. Heat acclimation (HA) involves repeated heat exposures that many endurance athletes use to optimize performance and safety when competing in the heat. Although HA has been shown to improve endurance performance in the heat, contention remains whether it may confer these adaptations to a cool environment. PURPOSE: To Investigate physiological and performance adaptations in a cool environment following HA in endurance athletes. METHODS: Eleven high-level endurance runners (4 males [age: 21 ± 4 years; body mass: 78.63 ± 9.01 kg; height: 182.55 ± 3.97 cm; maximal oxygen uptake {VO2max}: 73.93 ± 9.69 ml·kg-1·min-1]; 7 females [age: 22 ± 5 years; body mass: 64.30 ± 7.97 kg; height: 168.00 ± 6.43 cm; VO2max: 58.30 ± 4.28 ml·kg-1·min-1]) participated in this study. At baseline, participants completed a combined VO2max and lactate threshold (LT) test, followed by an 8-km time-trial (TT) in cool conditions (ambient temperate [Tamb], 11°C; relative humidity [RH], 40%). Following this, participants completed a 7-day protocol consisting of 60-min running at 50% velocity at VO2max in a hot environment (Tamb, 40°C; RH, 35%). Physiological variables (i.e., heart rate [HR], core temperature [Tc], sweat rate [SR], plasma volume change [ΔPV]) were assessed on days 1 and 7. A post-testing visit that followed the same protocol as the pre-testing visit was conducted to determine performance changes. A two-way repeated measures ANOVA was conducted to assess physiological and performance changes from pre- to post-testing for performance variables, and from days 1 to 7 for physiological variables, between sexes. Cohen’s d classification of effect sizes was calculated. RESULTS: In a cool environment, a significant interaction between males and females from pre- to post-testing was observed for VO2max, (p = 0.005) but not for velocity at LT or 8-km TT (p \u3e 0.05). Particularly, females demonstrated improvements in VO2max (57.62 ± 5.49 to 61.81 ± 6.16 ml·kg-1·min-1; p = 0.01; d = 0.68), but males did not (p \u3e 0.05). Regardless of sex, velocity at LT was improved from pre- to post-testing (10.5 ± 0.3 to 11.0 ± 0.3 mi·h-1; p = 0.05; d = 1.67), whereas TT remained unchanged (p \u3e 0.05; d = 0.14). From day 1 to 7 of HA, there were no significant interactions between males and females in maximum HR, maximum Tc, ΔPV, and SR (p \u3e 0.05). Irrespective of sex, maximum HR was reduced (183 ± 3 to 175 ± 2 bpm; p = 0.014; d = 3.14), whereas maximum Tc, ΔPV, and SR were unchanged (p \u3e 0.05; d = 0.38 - 1.86). CONCLUSION: The present findings indicate that HA may procure adaptations to improve endurance performance in cool temperatures in both male and female endurance runners
Developing an Evidence-Based Model for Healthy Stride Length Prediction
Full text linkStride length is a vital health indicator, reflecting physical fitness and mobility status. Although several existing formulas aim to estimate stride length, many are limited by a lack of scientific validation, especially among healthy, active adults. This study addresses these limitations by developing a validated model based on healthy adults without known mobility impairments, aiming to establish a more accurate, clinically useful standard for stride length estimation. The model provides a reference range for healthy stride length, usable as a tool to identify individuals at risk of mobility issues. PURPOSE: To develop an evidence-based model for predicting stride length using key physical indicators in a healthy adult population. METHODS: A total of 240 healthy adults (20 per gender per decade, ages 19-90) participated in this study. The sample was randomly split, with 80% used for training and 20% for testing. Stride length (cm) was measured using the GAITRite system as participants walked at their usual, self-selected normal speed for two minutes. Predictor variables included sex, age, height (cm), and body weight (kg). The final model was developed using multiple regression analysis on the training dataset and was cross-validated using the testing dataset. Model performance was assessed by comparing predicted stride lengths with actual measurements using R², standard error of estimate (SEE), and mean difference. Additionally, a prediction interval was calculated to estimate the healthy range of stride length. RESULTS: The average age and stride length were 49.7 ± 18.2 years and 137.7 ± 14.2 cm, respectively. The final model demonstrated acceptable predictive accuracy (R² = 0.46; SEE = 9.50) with a prediction interval of ± 3.0 cm. The equation for estimated stride length was 34.70 – 0.30 × (age) + 0.76 × (height[cm]) – 0.15 × (weight[kg]) – 3.33 × (sex [male = 0; female = 1]). Cross-validation showed no significant difference between actual stride length (137.5 ± 12.9 cm) and predicted stride length (135.5 ± 8.8 cm; p = 0.185). CONCLUSION: The developed model demonstrated acceptable predictive accuracy for estimating healthy stride length. This model not only serves as a practical tool for assessing gait health but also establishes a reference range for healthy stride length
A 6-week Lagree Intervention Improves Dynamic Balance and Functional Movement Screen Performance
Full text linkLagree methodology is an increasingly popular novel progressive exercise program similar to Pilates. However, no research has prospectively examined its effects on functional performance and balance. PURPOSE: To determine the effectiveness of a 6-week Lagree methodology program on functional performance and balance in healthy adults. METHODS: Eight healthy adults (6F, 26±10 years, 71.6± 22.1 kg, 163±12 cm) participated in this exploratory case series. Participants completed all 7 movement components of the Functional Movement Screen (FMS) and Lower Quarter Y-Balance Test pre- and post-intervention. This 6-week Lagree program involved progressive resistance training via 11 different exercises (e.g., planks, runner’s lunge squat, hinging torso twist, knee strap crunch, reverse giant wheelbarrow, etc.) performed on a machine with a platform lift. Participants followed video instruction conducted by the founder of the Lagree Methodology while trained researchers monitored the exercises form. The intervention progressively increased the number and duration of sessions, exercise tempo, and activity difficulty. Changes in FMS and composite Y-Balance test score were assessed using paired t-tests. RESULTS: The total FMS score significantly increased by approximately 41% from pre-to post-intervention (pre: 11.3±3.7, post: 15.9±2.6, p=0.002). And composite scores of the y-balance test on their non-dominant leg significantly increased by 7% post-intervention (pre: 235.7±20.9 cm, post: 252.2±26.8 cm, p=0.035). The composite scores on the dominant increased by 4% but these differences were not significant (pre: 238.9±21.5 cm, post: 248.7±27.6 cm, p=0.140). CONCLUSION: A 6-week Lagree intervention was effective in producing significant and substantial improvements in functional movement and dynamic balance as measured by the FM and Y-Balance. These findings suggest that Lagree methodology may offer functional performance benefits in healthy adults
Low-Energy Cooling Strategies to Mitigate Thermal Strain of Older Adults Exposed to Very Hot-Dry Heat
Full text linkExtreme heat causes morbidity and mortality, particularly among older adults. Although air conditioning can mitigate heat strain, it may be inaccessible due to limited resources, high costs, or power outages. Consequently, cooling strategies other than air-conditioning are needed to mitigate excessive elevations in core temperature and cardiovascular strain in this population. While electric fans offer a low-cost and widely available intervention, their effectiveness in very hot conditions is minimized due to potential increases in heat gain and dehydration. In contrast, skin wetting is a promising low-cost and energy-free cooling strategy that enhances evaporative heat loss. PURPOSE: We tested the hypotheses that skin wetting via water spray attenuates, whereas fans increase, elevations in core temperature and the accompanying cardiovascular strain in older adults exposed to very hot-dry heat with accompanying activities of daily living. METHODS: In a randomized order, 20 older adults (73±5 years; 10 Females) were exposed to 3-hours of ambient heating reflective of the peak environmental conditions during the 2018 Los Angeles heat wave (47ºC, 15% relative humidity) with: a) whole-body skin-wetting every 10 min via water spray, b) continuous electric fan exposure (~2 m/sec), and c) without a cooling intervention (control). To simulate activities of daily living, participants performed six, 5-minute periods of light exercise (~3 METS) dispersed across the heat exposure. Participants consumed 3 mL/kg/hr of tap-temperature water to offset dehydration. We assessed core and skin temperatures, whole-body sweat rate, heart rate, and rate pressure product (heart rate x systolic blood pressure). We compared data using mixed-effects models with a main effect of cooling, and post hoc Dunnett tests to compare against control. RESULTS:: Compared to control, water spray reduced the increase in core temperature by -0.24 °C [95% CI: -0.41 to -0.07; p=.005], ending skin temperature by -2.1°C [95% CI: -2.7 to -1.6; pCONCLUSION:These data demonstrate that water spray attenuates, while an electric fan exacerbates, core temperature and the accompanying cardiovascular strain in older adults exposed to very hot and dry conditions
Comparison of 3-Dimensional Scanning and Dual-Energy X-Ray Absorptiometry for Body Composition Estimation in Muscular, Resistance-Trained Adults
Full text linkAccurate body composition analysis is crucial for a comprehensive understanding of health and performance. While dual energy X-ray absorptiometry (DXA) is a widely accepted laboratory method, 3D scanners offer a convenient alternative. However, the validity of these technologies in resistance-trained adults remains uncertain. PURPOSE: This study compared the accuracy of professional and smartphone-based 3D scanning technology with DXA for estimating fat-free mass (FFM) and body fat percentage (BF%) in muscular, resistance-trained individuals. METHODS: Resistance-trained participants who met prespecified criteria for BF% and fat-free mass index (FFMI) were evaluated using DXA (GE iDXA), a professional 3D scanner (Size Stream SS20), and a smartphone-based 3D scanner (Size Stream Me Three Sixty). Thirty-one individuals were included in the present analysis, including 14 females ([mean ± SD] age: 29.1 ± 8.8 y, body mass: 66.5 ± 6.1 kg, height: 165.0 ± 5.7 cm, DXA BF%: 22.6 ± 3.4%, DXA FFMI: 18.9 ± 1.2 kg/m2) and 17 males (age: 28.8 ± 8.7 y, body mass: 83.5 ± 8.9 kg, height: 177.0 ± 7.3 cm, DXA BF%: 13.5 ± 3.8%, DXA FFMI: 23.1 ± 1.6 kg/m2). The agreement between DXA and 3D scanning estimates of FFM and BF% were examined through the coefficient of determination (R2), Bland-Altman analysis, and validity statistics. RESULTS: The R2 values between DXA and professional 3D scanning FFM estimates were 0.53 (females), 0.89 (males), and 0.92 (all) [p\u3c0.001 for each], while the R2 values between DXA and smartphone-based 3D scanning were 0.60 (females), 0.86 (males), and 0.92 (all) [p\u3c0.001 for each]. In the total sample, smartphone-based 3D scanning significantly underestimated FFM by 4.1 ± 3.6 kg (p\u3c0.01), while professional 3D scanning did not (mean difference: -1.3 ± 3.8 kg; p=0.07). For BF%, the R2 values between DXA and professional 3D scanning were 0.18 (females; p=0.13), 0.14 (males; p=0.15), and 0.35 (all; p\u3c0.001), while the R2 values between DXA and smartphone-based 3D scanning were 0.08 (females; p=0.33), 0.00 (males; p=0.79), and 0.47 (all; p\u3c0.001). In the total sample, smartphone-based 3D scanning overestimated BF% by 5.3 ± 4.6% (p\u3c0.01), while professional 3D scanning did not (mean difference: 1.3 ± 5.0%; p=0.15). Minimal proportional bias was observed when all participants were combined, but some instances of sex-specific proportional bias were noted. CONCLUSION: The FFM results from the professional 3D scanner generally aligned with DXA, while systematic underestimation of FFM was observed for the smartphone-based 3D scanner. Both 3D scanning methods demonstrated poorer performance in females than males for FFM, as well as poor overall performance for BF% estimation. These results highlight the need for further refinement of 3D scanning technologies before they are widely used for the assessment of body composition in muscular, resistance-trained adults