Experienced Runners Research Articles

Multidisciplinary, biopsychosocial factors contributing to return to running and running related stress urinary incontinence in postpartum women

ObjectivesTo examine contributory factors behind postpartum return-to-running and return to pre-pregnancy running level, in addition to risk factors for postpartum running-related stress urinary incontinence (SUI).Methods881 postpartum women completed an online...

Social Disparities and Food Environment Determinants of Food Insecurity Among Graduate Students in the United States During the COVID-19 Pandemic

ObjectivesThe COVID-19 pandemic is worsening food insecurity and exacerbating social disparities. This study investigated the pandemic's impact on food insecurity, disparities, and determinants among graduate students at Purdue University, a public research university.MethodsPurdue University graduate students completed a Graduate Student Experience in the Research University Survey (gradSERU) in Apr-Jun 2019 and the Fostering Food Security, Health, and Resilience in Graduate Education (FORGE) survey in Nov-Dec 2020, which assessed students’ food security, mental and physical health, and academic performance. A validated two-question tool measured food insecurity based on worry over or experience of running out of food without the ability to purchase more. Analyses using logistic regressions were performed in StataSE16.ResultsFood insecurity among graduate students doubled from spring 2019 (17%) to fall 2020 (36%, P < 0.001), increasing for all races, genders. Odds of food insecurity in 2020 were higher among students who were African American (OR: 5.7, 95% CI 3.2–10.1), Asian (OR 3.1 [2.1–4.8]), Hispanic or Latino (OR 3.0 [1.8–4.0]), international (OR 1.5 [1.2–1.8]), LGBTQ+ (OR 1.9 [1.4–2.6]), caregiving for adults (OR 2.7 [1.9–3.6]), or funded through fellowships or assistantships (vs. personally funded, OR 1.5 [1.1–2.0]). Food insecure students faced greater stress (OR 3.5 [3.0–4.2]) and reduced ability (OR 0.6 [0.5–0.8]) to attain a healthy diet, with reduced access to stores with fruits and vegetables (OR 0.7 [0.6–0.9]) or considered good quality (OR 0.4 [0.3–0.5]). Food insecure students were more likely (OR 6.7 [5.2–8.6]) or vegetables (OR 8.1 [6.1–10.9]) due to cost. Lack of time (52%), culturally desired foods (11%), and transportation (10%) were limitations to a healthy diet.ConclusionsGraduate student food insecurity increased significantly during the COVID-19 pandemic, particularly among international, minority, and LGBTQ + students, and coincided with lower likelihood of purchasing nutritious foods. Universities should implement policies and services to address persistent and increasing food insecurity and disparities among graduate students.Funding SourcesProtect Purdue Innovations Faculty Grant.

Comparison of Frontal and Transverse Plane Kinematics Related to Knee Injury in Novice Versus Experienced Female Runners.

Novice runners experience a higher incidence of knee injury than experienced runners, which may be related to aberrant frontal and transverse plane kinematics. However, differences in kinematics between novice and experienced runners have not been fully explored. For this study, 10 novice and 10 experienced female runners ran on a treadmill at 2.68m/s. Ankle, knee, and hip joint angles during the stance phase were measured using a 3-dimensional motion capture system and modeled using cubic splines. Spline models were compared between groups using a generalized linear model (α = .05). Ninety-five percent confidence intervals of the difference between joint angles throughout stance were constructed to identify specific periods of stance where groups differed in joint position. Angle-angle diagrams of ankle and hip position in the frontal and transverse planes were constructed to depict joint coordination. Novice runners displayed less hip adduction, but greater knee abduction and knee internal rotation compared to experienced runners. Differences in knee joint position may be explained by coordination of hip and ankle motion. Greater knee abduction and knee internal rotation displayed by novice runners compared with experienced runners may help to explain their higher risk for injury.

Marathon shoes vs. track spikes: a crossover pilot study on metabolic demand at different speeds in experienced runners

ABSTRACT The aim of this study was to assess the metabolic cost (Cr) with marathon shoes (Adidas Adizero 3 [AA]) vs. track spikes (Nike Zoom Matumbo 3 [NZM]) on track. For this, five experienced runners were randomly assessed (NZM/AA) on a running track at 73% and 85% of best performance speed on 1500-m race. At first, speed (4.39 ± 0.53 m·s−1), Crs with AA and NZM resulted 3.63 ± 0.29 and 3.64 ± 0.43 J·kg−1·m−1 (+0.3% with NZM, effect size [ES] small and p = 0.951), respectively. Besides, at second speed (5.20 ± 0.18 m·s−1), Crs were 4.09 ± 0.28 and 4.07 ± 0.22 J·kg−1·m−1 (−0.5% with NZM, ES small and p = 0.919) with AA and NZM, respectively. It resulted in an increased Cr (+12.2%) between s1 and s2 with both shoe conditions (ES large and p = 0.009 and 0.011 with AA and NZM, respectively). There is a pattern yet to be confirmed for track spikes to become more beneficial at higher speeds (when duty factor becomes lower and therefore grip on track is crucial).

The effect of uneven terrain conditions during shod vs. barefoot running

Background: The majority of research on barefoot running focuses on acute changes in altering footwear without regard to the runner's experience with barefoot or minimalist footwear running. Objective: The objective of this study was to compare the effect of footwear (standard cushioned running shoes, barefoot) and running surface (flat surface, uneven terrain) on gait in experienced runners using minimalist shoes. Methods: Terrain running was simulated by three custom-made mats with randomly placed firmly attached stones. Seven experienced trail runners participated in this study. All participants were forefoot strikers. Participants underwent three-dimensional kinematic and kinetic analysis consisting of five running trials in each combination of footwear and surface. A trial was successful when the participant maintained a velocity of 3.2 &#177; 0.16 m/s without targeting a force platform. Results: Uneven terrain conditions along with barefoot conditions led to significantly decreased peak moment of ankle plantarflexion (terrain: p = .041, footwear: p = .026) and decreased second peak of vertical ground reaction force in comparison with other conditions (terrain: p = .026, footwear: p = .004). Uneven terrain conditions also significantly decreased ankle dorsiflexion at initial contact with the ground for both footwear conditions (p = .021). Conclusions: We conjecture that net ankle moments could be decreased by barefoot running in terrain conditions in skilled forefoot runners. Experienced runners using minimalist shoes may incorporate trail running into their barefoot running regime without risk of higher Achilles tendon loading compared to even running.

The Effectiveness of the Psychological Intervention in Amateur Male Marathon Runners

Background: The Marathon runners must have the proper technical preparation to reach excellence and to achieve adequate psychological preparation for the race. Against this background, the current study aims to describe the implementation results of a cognitive-behavioral intervention based on psychological skills training for marathon runners.Methods: Fourteen amateur male marathoners with an average age of 30 (SD = 5.75) were trained with various emotional and cognitive control techniques to enhance their performance in competition. Various psychological variables, related to the subjects level of perceived stress, and to qualitative characteristics of their thoughts were measured before and after the target marathon race. Results were analyzed through non-parametric tests for two related samples. The Cohen's d effect size for single-group pretest-posttest repeated measures were also performed.Results: Statistical analysis reveals that, controlling for age and running experience, the intervention decreased significantly the level of perceived stress and the occurrence of negative thoughts before the race, during, and after the race.Conclusion: Training in cognitive control and relaxation techniques, as part of the psychological skills training could determine the quality of performance of marathon runners.

Effects of a 48-Day Home Quarantine during the Covid-19 Pandemic on the First Outdoor Running Session among Recreational Runners in Spain.

COVID-19-induced quarantine may lead to deleterious effects on health status as well as to impaired performance and increased injury risk when re-starting training after lockdown. We investigated the physical activity (PA) habits of recreational runners in Spain during a 48-day home quarantine during the COVID-19 pandemic and the characteristics of the first outdoor running session after confinement. A cross-sectional study, including a self-reported running questionnaire completed after the first outdoor running session after quarantine, was performed. Three hundred recreational runners (74% males; 60% 18–40 years old; most typical running experience >3 years, 10–30 km weekly running distance distributed in 3–4 sessions) were considered for analysis. Advanced runners ran, at least, 4 days/week and participated in running events. They performed significantly longer and more non-supervised weekly training sessions during confinement (p < 0.01 for both) than novice and amateur runners. Most runners performed their first outdoor running session on asphalt (65.3%) and ran 5 to 10 km (61%) at a pace above 5 min/km (60%), reporting no pain before (77%), during (64%), and 24 h after (76%) the session. Advanced runners performed a significantly longer running session, at a higher pace, and covered a greater distance (p < 0.01 for all) than novice and amateur runners, while enjoyment and motivation tended to be significantly higher when runners’ level increased (p < 0.05). Higher training levels prior to and during confinement may lower the collateral effects (e.g., detraining, injury risk) of home quarantine when runners return to previous PA levels.

Muscle Tone and Body Weight Predict Uphill Race Time in Amateur Trail Runners.

Background: Vertical kilometer is an emerging sport where athletes continuously run uphill. The aims of this study were to assess changes in vertical impacts caused by uphill running (UR) and the relation between the anthropometric and lower limb muscular characteristics with speed. Methods: Ten male experienced runners (35 ± 7 years old) participated in this study. In the racetrack (4.2 km long, 565 m high), seven sections were stablished. Mean speed and impact value of sections with similar slope (≈21%) were calculated. The gastrocnemius stiffness (GS) and tone (GT); and the vastus lateralis stiffness (VS) and tone (VT) were assessed before the race. Results: Pearson’s correlation showed a linear relationship between vs. and VT (r = 0.829; p = 0.000), GT and GS (r = 0.792; p = 0.001). Mean speed is correlated with weight (r = −0.619; p = 0.024) and GT (r = 0.739; p = 0.004). Multiple linear regressions showed a model with weight and GT as dependent variables of mean speed. Mean impacts decreased significantly between sections along the race. Conclusions: The vertical impacts during UR were attenuated during the race. Moreover, body weight and GT were associated with the time-to-finish, which supports that low weight alone could not be enough to be faster, and strength training of plantar flexors may be a determinant in UR.

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.

Effect of gender and running experience on lower limb biomechanics following 5 km barefoot running

ABSTRACT Barefoot running has been increasing in popularity, yet there is a gap in understanding concerning the biomechanics of mid-distance barefoot running, especially between genders and runners of different running-experience levels. This study examines the effects of running-experience, gender, and their interaction on running biomechanics following 5 km barefoot running. Before and after a 5 km run, three-dimensional kinematics and kinetics of the lower limb joints and plantar pressure during barefoot running were collected from 20 participants. Participants were stratified by their running-experience levels (novice and marathon-experienced) and gender. This study revealed significant gender effects on lower limb biomechanics following a 5 km barefoot run. Increased plantar pressure under the lateral aspect of the foot was observed in the female cohort, while the male cohort exhibited reduced plantar pressure under the lateral heel. This study suggests that modified lower limb running biomechanics and modified lateral foot loading after 5 km barefoot running may create a different foot loading environment for female and male runners that should be accommodated in barefoot runningand minimalist shoe design.

Do Novice Runners Show Greater Changes in Biomechanical Parameters?

Purpose Examining and understanding the biomechanics of novice runners and experienced runners can further improve our knowledge within the field of running mechanics and running injuries. The purpose of this study was to classify the differences in lower limb biomechanics during a 3.3 m/s running task among both experienced runners and novice runners. Method Twenty-four participants (12 experienced runners and 12 novice runners) ran at 3.3 m/s across a force plate; kinematics and kinetics data were collected by the Vicon motion system and Kistler force plate. Group comparisons were made using an independent samples t-test to identify differences in the impact peak, loading rate, contact time, ankle, knee, and hip joint kinematics and kinetics during the stance phase. Results No significant differences were observed between novice and experienced runners for both ankle and knee joint kinetics except that the ankle joint plantar flexion torque was significantly greater in the novice runners. However, the plantar flexion, dorsiflexion, range of motion (ROM), plantar flexion torque, and max angular velocity of ankle joint significantly increased in novice runners than inexperienced runners. Additionally, the flexion angle and range of motion of the hip joint were observed to be larger in the novice runners. Moreover, the maximum extension torque and the maximum extension power in the hip joint were significantly increased in the experienced runners. There were no significant differences in the first peak, contact time, and average vertical loading rate. Novice runners showed a larger vertical instantaneous loading rate than experienced runners. Conclusion These preliminary findings indicate that novice runners are prone to running injuries in comparison to experienced runners. Novice runners showed larger kinematics and kinetic parameters in the joint of the ankle and hip. Novice runners should enhance muscle strength in the hip and choose scientific training methods.

How to rapidly convert general wards to ICUs during the COVID-19 epidemic: Experience from Wuhan, China.

BackgroundCritically ill patients with coronavirus disease 2019 (COVID‐19) were surging and far outnumbered existing beds.AimsTo describe how to rapidly convert general wards to intensive care units for critically ill patients with COVID‐19.Materials and MethodsComprehensive assessment and analysis of available resources and standard requirements.ResultsThe ICUs were successfully assembled in 4 days. The conversion included environment reconstruction, configuration and management of equipment, information system construction and human resource allocation. A total of 172 critically ill patients had been admitted to the contemporary ICUs and none medical staff was infected.DiscussionThe epidemic situation of COVID‐19 poses a great challenge to various management departments of the hospital, especially for critically ill patients with a high mortality rate. To save more critically ill patients, the conversion of a general ward to a quarantine ICU ward must be completed in a short time, and the optimal allocation of resources must be appropriate to ensure that the medical team works effectively and is of high quality. In face of the overloaded medical system, the ideal non‐negative pressure ward is hard to achieve. However, we have demonstrated with evidence that our conversions are effective in both providing care to critical patients and protecting the safety of our staff.ConclusionThe conversion is successful and the running experience would be a reference for hospitals in other areas nationally or globally.

Blueberry supplementation reduces the blood lactate response to running in normobaric hypoxia but has no effect on performance in recreational runners

BackgroundBlueberries are concentrated with anthocyanins possessing antioxidant properties. As these properties counter fatigue, blueberry supplementation may improve performance and recovery, particularly in hypoxia, where oxidative stress is elevated.MethodsThis study examined the effects of blueberry supplementation on running performance, physiological responses, and recovery in normobaric hypoxia. Eleven experienced runners completed a 30-minute time-trial (TT) in normobaric hypoxia (%O2 = 15.5 %) on separate days after supplementation with four days of blueberries (BLU) or four days of placebo (PLA). Heart rate (HR), oxygen saturation (SaO2) and ratings of perceived exertion (RPE) were monitored during the TT. Blood lactate and fraction of exhaled nitric oxide (FENO) were assessed pre-TT, post-TT, and during recovery.ResultsNo significant differences were observed in the distance run during the TT, HR, SaO2, and RPE. The post-TT increase in blood lactate was significantly lower in BLU than PLA (p = 0.036). Pre-TT and post-TT FENO did not differ between conditions. Blood lactate recovery following the TT was similar between conditions.ConclusionsFour days of blueberry supplementation did not alter running performance or cardiovascular and perceptual responses in normobaric hypoxia. Supplementation lowered the blood lactate response to running, however, the significance of this finding is uncertain given the absence of an ergogenic effect.

Impact of COVID-19 Social Distancing Restrictions on Training Habits, Injury, and Care Seeking Behavior in Youth Long-Distance Runners.

Purpose: The COVID-19 pandemic impacted the sporting and exercise activities of millions of youth. Running is an activity that could be maintained while social distancing restrictions were implemented during the pandemic. If running-related injuries do occur, these restrictions may also influence the access to care or care seeking behavior of this population. Therefore, the purpose of this study was to determine if the social distancing restrictions during the 2020 COVID-19 pandemic influenced training habits, injury, and care seeking behavior in youth long-distance runners.Methods: A customized, open online questionnaire was provided to runners 9–19 years of age who participated in long-distance running activities including team/club cross-country, track and field (distances ≥800 m), road races, or recreational running. Participants responded to questions about demographics, running habits, RRIs, and health care provider visits 6-months before as well as during social distancing restrictions due to COVID-19. Wilcoxon signed rank tests compared differences for ratio data and Chi-square tests were used to compare proportions before and during COVID-19 social distancing restrictions. Statistical significance was set at p ≤ 0.05.Results: A total of 287 youth long-distance runners (male = 124, female = 162, unspecified = 1; age = 15.3 ± 1.7 years; running experience = 5.0 ± 2.3 years) participated. Compared to their pre-COVID-19 responses, youth long-distance runners reported lower distances run per week (p < 0.001), fewer runs per week (p < 0.001), fewer hard runs per week (p < 0.001), fewer number of injuries (p < 0.001), and fewer injuries per 1,000 km (p = 0.002) during the COVID-19 social distancing restrictions. A lower proportion of participants reported in-person health care provider visits (p < 0.001) and a lower proportion of visits were made to an athletic trainer during COVID-19 social distancing restrictions compared to prior to COVID-19 (p < 0.001).Conclusion: The COVID-19 pandemic resulted in significant decreases in both training and injuries which were different compared to previous reports in an adult population. Many of the runners who sustained an injury during COVID-19 social distancing restrictions did not seek care, with the most prominent reduction in visits to an athletic trainer. This could impact future injury and chronic pain.

Study of the Motivation of Spanish Amateur Runners Based on Training Patterns and Gender.

The objectives of the present study are to analyze the different training patterns of the amateur runners, according to their gender, and to find out a correlation between the training pattern and the motivation. The sample was composed of 457 amateur runners. For the collection of data, a two-part questionnaire was used. The first part consisted of questions about sporting and healthy patterns and the second part consisted of the Perception of Success Questionnaire (POSQ), adapted to Spanish. The obtained results indicated that their motives for starting to practice running and to continue their involvement are health and fun. The training pattern is as follows: they practise one to three days per week, running from three to five hours overall plus additional stretching and high intensity training. They participated in less than one running event per month. Most of them did not belong to an athletic club, did not have a coach, were not federated and have more than four years’ experience of running. What concerns the gender differences, the men trained more than the women, and they did it with relatives and friends; women preferred to do it with friends or by themselves with the assistance of a coach. Age and running hours per week were the best variables to predict the task goal orientation, especially for men. For women, training hours per week predicted the goal orientation but to the ego. This finding could be especially helpful for coaches. A high number of training hours for men was linked with a task goal orientation, and on the other hand, for women it meant an ego goal orientation. The consequences of their behaviours were likely to be markedly different.

Changes of Mood and Cognitive Performance before and after a 100 km Nighttime Ultramarathon Run.

Ultramarathons are becoming an increasingly popular endurance sport. Year after year, the demands on athletes’ skills and endurance increase. Ultramarathons are particularly taxing on athletes’ psychological functioning. This study assessed the relationships between taking part in a nighttime ultramarathon and changes in mood and cognitive functioning. The study included 20 experienced runners aged 26–57 (M = 37.29; SD = 7.94) who had M = 7.08, SD = 5.41 (range 3–44) years of experience running. There were 18 men and 2 women. The mood states were measured twice, just before the start of the run and shortly after crossing the finish line, using the Polish version of the UMACL UWIST Mood Adjective Checklist by Mathews, Chamberlain, and Jones. To assess cognitive functioning, the Stroop Color and Word Test and “Forward digit span” subtest from the Wechsler Adult Intelligence Scale were used. We observed statistically significant changes in the mood of the runners: tense arousal, associated with the experienced stress, was significantly higher before the run than immediately after the finish. Moreover, we observed an improvement in cognitive functioning after finishing the 100 km run on both of the trials on the Stroop color word test and on the forward digit span test.

Proteinuria and Bilirubinuria as Potential Risk Indicators of Acute Kidney Injury during Running in Outpatient Settings.

Background and objectives: The purpose of this study was to explore which urinary markers could indicate acute kidney injury (AKI) during prolonged trail running in outpatient settings. Materials and Methods: Twenty-nine experienced trail runners (age 39.1 ± 8.8 years, weight 71.9 ± 11 kg, height 171.9 ± 8.3 cm) completed a 35 km event (cumulative positive ascend of 1815 m, altitude = 906 to 1178 m.a.s.l.) under a temperature of 25.52 ± 1.98 °C and humidity of 79.25 ± 7.45%). Two participant groups (AKI = 17 and No-AKI = 12) were made according to AKI diagnosis criteria based on pre- and post-race values of serum creatinine (sCr) (an increase of 1.5 times from baseline). Blood and urinalysis were performed immediately pre- and post-race. Results: Pre- vs. post-race differences in sCr and sBUN were found in both AKI and No-AKI groups (p < 0.01). Differences in post-race values were found between groups (p = 0.03). A total of 52% of AKI runners presented significant increases in proteinuria (χ2 = 0.94, p = 0.01) and 47% in bilirubinuria (χ2 = 0.94, p = 0.04). Conversely, No-AKI participants presented no significant increases in urine markers. Conclusions: These study’s findings may suggest the potential use of urinalysis as an accessible alternative in the outpatient setting to early identify transitional AKI until a clinical confirmation is performed.

How Do Runners Experience Personalization of Their Training Scheme: The Inspirun E-Coach?

Among runners, there is a high drop-out rate due to injuries and loss of motivation. These runners often lack personalized guidance and support. While there is much potential for sports apps to act as (e-)coaches to help these runners to avoid injuries, set goals, and maintain good intentions, most available running apps primarily focus on persuasive design features like monitoring, they offer few or no features that support personalized guidance (e.g., personalized training schemes). Therefore, we give a detailed description of the working mechanism of Inspirun e-Coach app and on how this app uses a personalized coaching approach with automatic adaptation of training schemes based on biofeedback and GPS-data. We also share insights into how end-users experience this working mechanism. The primary conclusion of this study is that the working mechanism (if provided with accurate data) automatically adapts training sessions to the runners’ physical workload and stimulates runners’ goal perception, motivation, and experienced personalization. With this mechanism, we attempted to make optimal use of the potential of wearable technology to support the large group of novice or less experienced runners and that by providing insight in our working mechanisms, it can be applied in other technologies, wearables, and types of sports.

Effects Of Minimal, Traditional, And Highly Cushioned Shoes On Injury-related Biomechanics In Rear And Non-rearfoot Strike Runners

Running barefoot, in minimal shoes, or traditional shoes alters certain injury-related biomechanical variables and these footwear effects can be influenced by foot strike pattern. It is unclear however how highly cushioned shoes might alter this interaction. PURPOSE: Given the increasing popularity in highly cushioned footwear in runners, this study assessed the interaction of footwear and foot strike pattern on injury-related biomechanical variables in experienced runners. METHODS: Six rear (RFS) and seven non-rearfoot strike (NRFS) experienced runners completed five running trials at 3.5m/s (±5%) in minimal (MSH), standard (SH) and high cushioned (HC) shoes. A mixed-design repeated measures ANOVA was used to test interaction effects for all injury-related variables. Paired t-tests were used to decipher any interaction effect and Cohen’s d effect sizes were computed to assess mean difference magnitudes. Given the preliminary nature of this work and the small sample size, alpha level was set to 0.1. RESULTS: Strike index confirmed the different strike patterns while running in SH between RFS (15.2±3.1%) and NRFS (102.8±11.8%) groups (p<0.001). Interaction effects were not observed for any of the variables except for peak eversion velocity (p=0.1) and instantaneous vertical loading rate (IVLR; p=0.1) (Figure 1). Main footwear effects were observed for IVLR (p=0.004) and peak eversion velocity (p=0.01). Main foot strike effects were observed for step length (p=0.041), strike index (p=0.00), and IVLR (p=0.00). CONCLUSION: Similar to prior research, these current preliminary findings suggest there might be an interaction between foot strike and footwear in experienced runners for peak eversion velocity and IVLR. Thus, if these biomechanical variables are of interest to scientists or clinicians, these findings suggest that footwear type and strike pattern should both be considered in research or return to running programs.Figure 1:: Instantaneous vertical loading rate (A; IVLR) and peak eversion velocity (B) in the three footwear conditions in rare (RFS; black) and non-rearfoot strike (NRFS; red) runners. *: foot strike group difference within footwear; #: footwear difference within foot strike group (p < 0.1).

A Validation Study Of A Treadmill Speed Incline Conversion Chart

PURPOSE: To investigate the accuracy of the Hillrunner.com treadmill speed incline conversion chart using ventilatory data, heart rate, subjective perceived effort, and blood lactate. METHODS: Two groups of experienced runners, divided based on their self-reported easy run pace, ran at 6 different speed/incline combinations for 5 minutes each. All stages were equivalent according to the HillRunner.com chart, and 1 minute standing rest was given between stages. Group 1 (n=11) ran at inclines up to 4%, while Group 2 (n=22) ran at inclines up to 10%. Oxygen consumption (VO2), respiratory exchange ratio (RER), heart rate (HR), blood lactate (BL), overall rate of perceived exertion (RPE), and leg RPE (LRPE) were measured for each stage. VO2 was compared against the VO2 predicted by the ACSM equation (ACSM.VO2). Stage order was randomized, and repeated-measures ANOVA was used to detect differences between stages and inclines. RESULTS: Measures of exercise intensity did not change as incline rose from 0% to 4% in Group 1 (p>.05). Increases in VO2 (42.2±3.6 to 45.9±4.0 mL.kg-1.min-1; p<.05), HR (146±12 to 151±12 bpm; p<.05), BL (1.4±0.9 to 1.9±1.2 mM; p<.05) and LRPE (10±2 to 12±2; p<.05) were found as incline increased from 0% to 10% in Group 2. When compared with VO2, ACSM.VO2 underestimated oxygen consumption at all inclines up to 8% (p<.05). ACSM.VO2 was similar to VO2 at an incline of 10% in Group 2 (45.9±4.0 vs. 46.7±2.4 mL.kg-1.min-1; p>.05). Within subjects, pooled results show moderate correlations between HR and BL at 0% and 2% (R=0.478, R=0.587; p<.01) but not at 4% (R=0.309; p>.05). Statistically significant correlations were also found between HR and BL at 6%, 8%, and 10% (R=0.601, R=0.560, R=0.600; p<.01) in the Group 2 participants. CONCLUSIONS: The HillRunner.com chart appears valid at relatively low inclines. However, at higher inclines, the decreases in speed may not prevent increases in exercise intensity as measured with VO2, HR, BL, and LRPE. The ACSM VO2 prediction equation underestimates oxygen consumption in a trained population at inclines up to 8%.