Pacing in age group marathoners in the “New York City Marathon”

The aim of the study was to investigate how women and men age group runners pace during a large city marathon. We analysed changes in running speed by splits of 5 km in 20,283 women and 28,282 men age group runners competing in the 2015 edition of the “New York City Marathon”. A moderate split×sex interaction on running speed (p < 0.001, η² = 0.108) was observed with men showing a larger decrease in speed from the fastest split (5–10 km) to the slowest one (35–40 km) than women (21.1 vs. 16.7%), and a different pattern was observed in the 25–30 km split (increase in women, decrease in men). A trivial split×age group interaction on speed was observed in women (p < 0.001, η² = 0.003) and men (p < 0.001, η² = 0.004). In summary, men and women of all age groups reduced running speed during the marathon with a final spurt in the last segment (i.e. 40–42.2 km).     

Stress fractures of the femoral neck in runners: a review

A systematic review, following strict inclusion criteria, identified 32/48 low and 16/48 high-performance runners with stress fractures of the femoral neck. Surgical treatment was performed in 33/48 cases and was significantly higher (p = 0.009) in high-performance runners. Among the 28/48 runners who resumed running, there were significantly more lower-performance runners (23/32) than higher-performing runners (5/16) (p = 0.012) and significantly more non-displaced (22/30) than displaced fractures (6/18) (p = 0.014). Complicated cases showed significantly less favourable follow-up results (p = 0.036). A significantly shorter (p = 0.032) diagnostic time for evaluation occurred with a previous history of a stress fracture or a relevant comorbidity. Stress fractures of the femoral neck represent an incisive incident for runners, and early consideration in the differential diagnosis of hip pain is required to avoid potential long-term sequelae and suboptimal function.     

Does running speed affect the response of joint level mechanics in non-rearfoot strike runners to footwear of varying longitudinal bending stiffness?

BackgroundModifying the longitudinal bending stiffness (LBS) of footwear has become a popular method to improve sport performance. It has been demonstrated to influence running economy by altering lower extremity joint level mechanics. Previous studies have only examined within-participant effects at one running speed.Research questionDo joint level mechanics differ in response to varying footwear LBS at a range of running speeds?MethodsThis study utilized a cross-sectional repeated measure study design using a convenience sample. Ten well trained non-rearfoot strike male distance runners ran at 3.89, 4.70, and 5.56 m/s (14, 17, 20 km/hr) in footwear of three different LBS levels. Mechanics and energetics of the metatarsophalangeal joint (MTPJ), ankle, knee, and hip joints during stance phase were assessed using an 8-camera optical motion capture system (f_s = 200 Hz), a force instrumented treadmill (f_s = 1000 Hz) and standard inverse dynamics theory.ResultsRange of motion and negative work decreased and angular stiffness increased for the MTPJ with increasing LBS at all speeds (p < .001). Peak MTPJ moment did not change at any speed in response to increased LBS. Negative work at the ankle decreased in the stiff shoe at 17 km/hr (p = .036). Peak ankle plantar flexion velocity decreased with increasing LBS at all speeds (p < .05).SignificanceWhile changes in MTPJ mechanics were consistent across speeds, decreased negative ankle work was only observed at 17 km/hr in the stiff shoe, suggesting that perhaps tuned footwear LBS may need to focus primarily on metabolically beneficial changes in ankle plantar flexor mechanical behavior to improve performance in distance runners. Tuning footwear stiffness may also be beneficial to clinical populations, as clinicians seek to optimize their patients’ locomotion economy.     

Ultra-obligatory running among ultramarathon runners

Participants in the Ultrarunners Longitudinal TRAcking (ULTRA) Study were asked to answer “yes” or “no” to the question “If you were to learn, with absolute certainty, that ultramarathon running is bad for your health, would you stop your ultramarathon training and participation?” Among the 1349 runners, 74.1% answered “no”. Compared with those answering “yes”, they were younger (p < 0.0001), less likely to be married (p = 0.019), had less children (p = 0.0095), had a lower health orientation (p < 0.0001) though still high, and higher personal goal achievement (p = 0.0066), psychological coping (p < 0.0001) and life meaning (p = 0.0002) scores on the Motivations of Marathoners Scales. Despite a high health orientation, most ultramarathon runners would not stop running if they learned it was bad for their health as it appears to serve their psychological and personal achievement motivations and their task orientation such that they must perceive enhanced benefits that are worth retaining at the risk of their health.     

Influence of hamstring flexibility on running kinematics in adolescent long-distance runners

BackgroundStudies have found no or minimal differences in running kinematics between flexible and inflexible adult runners. The interaction between hamstring flexibility and running kinematics has not been reported in adolescent long-distance runners.Research questionDoes hamstring flexibility influence running kinematics in adolescent long-distance runners?MethodsAdolescent long-distance runners (n = 140, ages 9–19) were enrolled in our cross-sectional study. Hamstring flexibility was assessed with the forward bending Beighton task. Runners were categorized if they tested positive or negative on the forward bending task. Participants ran at a comfortable self-selected speed on a treadmill. Runners who tested positive on the forward bending task (n = 17) were matched with runners who tested negative on the task (n = 17) according to sex, physical maturation, and running speed. Statistical parametric mapping compared trunk, pelvis, hip, and knee kinematic waveforms throughout the gait cycle and independent sample t tests compared temporal-spatial parameters between the groups.ResultsRunners who tested positive on the forward bending task demonstrated significantly greater anterior pelvic tilt during stance (average difference = 4.8° ± 0.4°, p < .001) and swing (average difference = 4.3° ± 0.2°, p < .01) compared to runners who tested negative on the forward bending task. No significant differences were found between groups for the remaining kinematic waveforms or for any temporal-spatial parameters (p > .05).SignificanceThis is the first study to report the interaction between hamstring flexibility and running kinematics in adolescent long-distance runners. The greater anterior pelvic tilt demonstrated by runners with greater hamstring flexibility may place more eccentric demands on the hamstring musculature. However, as there were no other differences in joint kinematics or temporal-spatial parameters between groups, greater hamstring flexibility does not appear to have a significant interaction with running kinematics when running at sub-maximal speeds. Our results suggest hamstring flexibility does not predispose adolescent long-distance runners to sub-optimal segment positions associated with running-related injuries.     

The age of the best ultramarathon performance – the case of the “Comrades Marathon”

The aim of the present study was to determine the age of the fastest running speed in 202,370 runners (34,090 women and 168,280 men) competing in the “Comrades Marathon” between 1994 and 2015 using non-linear regression analysis (second order polynomial function). When all runners were considered in 1-year age intervals, the fastest running speed (9.61 ± 1.65 km/h) was achieved at the age of 29.89 years in men, whereas women achieved it at the age of 35.96 years 8.60 ± 1.10 km/h. When the fastest runners were considered in 1-year intervals, the fastest running speed (16.65 km/h) was achieved in men at the age of 36.38 years. For the fastest women, the age of the fastest running speed (13.89 km/h) was 32.75 years. To summarize, for all runners, men achieved the best ultramarathon performance ~6 years earlier than women. When the fastest runners were considered, however, men achieved the best performance ~4 years later than women.     

Differences in injury risk and characteristics of injuries between novice and experienced runners over a 4-year period

Objectives: Running is increasingly popular, but also carries a high injury risk, especially in novice runners. This study investigates differences in incidence and characteristics of running-related injuries (RRIs) between novice and experienced runners in the open population, in order to adapt to more specific needs for future prevention programs.

Methods: Data were obtained from Injuries and Physical Activity in the Netherlands (IPAN), a Dutch questionnaire on injuries, physical activity, and sports. A representative sample of runners (n = 4621) from IPAN, including 1405 novice runners, was used to assess injury incidence rates, anatomical site, onset and need for medical attention of RRIs. Participants who started running during the past 12 months were defined as ‘novice’ runners. ‘Experienced’ runners are participants who had been running for more than 1 year.

Results: Of the 4621 runners, 41,8% were female. The average age was 34.2 years. From 2010 to 2013, a total of 416 injuries were reported. The incidence of RRIs was significantly higher in novice runners compared with experienced runners: 8.78 (8.59–8.96) vs. 4.24 (4.11–4.37) per 1000 h running. In both novice and experienced runners, most RRIs were located at the knee (30.5%) and lower leg (17.8%), with the Achilles’ tendon less frequently injured in novice runners (2.3% vs. 8.4%, p = 0.031). Novice runners sustained more medical attention injuries (36.8%) than experienced runners (29.2%) (p > 0.132).

Conclusions: In total, over 30% of all (novice and experienced) runners, suffered from RRI within 1 year. Novice runners reported more injuries per 1000 h of running in comparison to experienced runners. A tendency toward receiving medical attention more frequently was found in novice runners compared to experienced runners. In view of this higher injury incidence of RRIs and healthcare consumption in novice runners, more studies are needed to develop effective injury prevention programs for novice runners.     

ProjectRun21: Do running experience and running pace influence the risk of running injury—A 14-week prospective cohort study

Objectives

The health benefits from participation in half-marathon is challenged by a yearly running-related injury (RRI) incidence proportion exceeding 30%. Research in injury etiology is needed to successfully prevent injuries. The body’s load capacity is believed to play an essential role for injury development. Therefore, the purpose of ProjectRun21 was to investigate the association between load capacity defined as running experience and running pace, and RRI when following a specific half-marathon running schedule.

Ankle Dorsiflexion displacement is associated with hip and knee kinematics in females following anterior cruciate ligament reconstruction

The purpose of this study was to examine associations between ankle dorsiflexion (ankle-DF) displacement and knee and hip kinematics and kinetics during a jump-landing task in females following anterior cruciate ligament reconstruction (ACLR). Females (n = 23) with a history of unilateral ACLR (≥ 6-months post-ACLR) underwent a three-dimensional lower extremity biomechanical evaluation. Pearson Product Moment (r) correlations assessed associations between ankle-DF displacement and knee and hip kinematic and kinetic variables. On the involved-limb, individuals with lesser ankle-DF displacement demonstrated greater knee abduction displacement during the loading phase (r = -0.645, p = 0.001). On the uninvolved-limb, individuals with greater ankle-DF displacement demonstrated greater hip flexion displacement (r = 0.599, p = 0.003) and knee flexion displacement (r = -0.545, p = 0.007). There were no other significant associations between ankle-DF displacement and ankle, knee, or hip biomechanical variables on either limb (p > 0.05). Our findings demonstrate that reduced ankle-DF motion appears to share a different relationship between the involved- and uninvolved-limbs in females post-ACLR.     

Medial tibial pain pressure threshold algometry in runners

Purpose

Pressure algometry (PA) may provide an objective and standardised tool in assessing palpation pain over the tibia. The purpose of this study was to analyse the intra-rater repeatability of PA and to determine whether tibial tenderness in healthy runners differ from runners with medial tibial stress syndrome (MTSS).

Methods

Pressure algometry was performed on 20 asymptomatic runners (40 legs) and 9 MTSS patients (14 symptomatic legs) at standardised locations along the medial border of the tibia. Intra-rater reliability was assessed in 10 randomly selected asymptomatic runners through repeated measurements 2 weeks later.

Results

Intra-rater reliability was moderate to excellent (ICC 0.53–0.90) in asymptomatic runners. Pain pressure threshold (PPT) was significantly reduced at 2/9–5/9 of the distance from the medial malleolus to the medial tibial condyle (p = 0.002–0.022). There was evidence of a statistically significant association between both height and weight, and PPT from the 3/9 (r = 0.416, p = 0.008) to 7/9 (r = 0.334, p = 0.035) and 3/9 (r = 0.448, p = 0.004) to 6/9 (r = 0.337, p = 0.034) area, respectively. In both MTSS patients and healthy runners, there was evidence of lower PPT in females compared to males (p = 0.0001–0.049) and a negative association between age and PPT (p = 0.001–0.033). MTSS patients had significantly lower PPT at the 3/9 site (p = 0.048) compared to asymptomatic runners.

Conclusion

Pain pressure threshold algometry can be incorporated into MTSS clinical assessment to objectively assess pain and monitor progress. The presence of reduced medial tibial PPT in asymptomatic runners suggests that clinicians may not need to await resolution of medial tibia tenderness before allowing return to sport in MTSS patients.

Level of evidence

III.     

Wearing compression socks during exercise aids subsequent performance

Objectives

To assess the effect of wearing compression socks on immediate and subsequent 5 km running time trials, with particular attention to the influences on physiological, perceptual and performance-based parameters.

Do novice runners have weak hips and bad running form?

First, we sought to better understand the predisposition of novice female runners to injury by identifying potential differences in running mechanics and strength between experienced female runners and active novice runners. Secondly, we aimed to assess the relationship between hip and trunk strength with non-sagittal hip kinematics during running. Two female populations were recruited: 19 healthy experienced runners and 19 healthy active novice runners. Strength measurements of the hip abductors and external rotators were measured using a hand held dynamometer while trunk endurance was assessed via a side-plank. Next, an instrumented gait analysis was performed while each participant ran at 3.3 m/s. Group comparisons were made using an independent t-test to identify differences in the impact peak, loading rate, peak non-sagittal hip joint angles, trunk endurance, and hip strength. Pearson's correlation coefficients were calculated between hip kinematics and strength measurements. There were no statistically significant differences in impact peak, loading rate, peak non-sagittal hip kinematics, or strength. However, the novice runners did show a clinically meaningful trend toward increased peak hip internal rotation by 3.8° (effect size 0.520). A decrease in trunk side-plank endurance was associated with an increased peak hip internal rotation angle (r = −0.357, p = 0.03), whereas isometric strength was not related to kinematics. Programs aiming to prevent injuries in novice runners should target trunk performance and possibly hip neuromuscular control, rather than hip strength.     

Biomechanical correlates of running performance in active children

Objectives

Examine the running kinematics in healthy, physically active prepubescent children and to determine if specific biomechanical factors correlate with running performance.

Biomechanics of graded running: Part II—Joint kinematics and kinetics

Compared to level running (LR), different strategies might be implemented by runners to cope with specific challenges of graded running at different speeds. The changes in joint kinetics and kinematics associated with graded running have been investigated, but their interactions with speed are unknown. Nineteen participants ran on an instrumented treadmill at five grades (0°, ±5° and ± 10°) and three speeds (2.50, 3.33 and 4.17 m/s), while 3D motion and forces were recorded. Three speed × five-grade repeated-measures ANOVA was used to analyze kinetic and kinematic variables. A speed × grade interaction was observed for hip range of motion (ROM). Downhill running (DR) at fastest speed did not reduce ROM at the hip, compared to LR. Compared to LR, it was observed that the hip joint was responsible for a greater contribution of energy generation while running at the fastest speed at +10°. Speed × grade interactions were also observed for the energy absorption, peak moment, and peak power at the knee. Contrary to LR, running faster during UR did not require higher peak power at the knee. Finally, DR at the fastest speed did not increase peak negative power at the knee compared to LR. This study demonstrates that ankle, knee, and hip joint kinetics depend on speed and grade of running, while the effect of grade on joint kinematics was not substantially modulated by speed.     

The effect of fatigue on running mechanics in older and younger runners

BackgroundThe presence of fatigue has been shown to modify running biomechanics. Throughout a run individuals become more fatigued, and the effectiveness of the musculoskeletal protective mechanism can diminish. Older adults are at an elevated risk for sustaining an overuse running related injury. This can be partially explained by changes in the musculoskeletal system and load attenuation.Research questionThe purpose was to compare post-fatigue running mechanics between older and younger runners.MethodsThirty runners (15 young, 15 older) between the ages of 18–65 participated in this study. All participants ran at least 15 miles/week. Running kinematics were captured using a 10-camera motion capture system while participants ran over a 10-m runway with force platforms collecting kinetic data under two conditions: C1: rested state at a controlled pace of 3.5 m/s ( ± 5%); C2: post-exertional protocol where pace was not controlled, rather it was monitored based on heartrate and RPE representative of somewhat-hard to hard intensity exercise. Prior to C2, participants underwent an exertional protocol that consisted of a maximal exercise test to induce fatigue and a required cool-down. A 2 (state of fatigue) x 2 (age) MANOVA was run to test for the effects of fatigue and age and their interactions. Results: No state of fatigue x age interaction was observed. A main effect of age for peak knee extension moment (Y > O; p = 0.01), maximum knee power (Y > O; p = 0.04), maximum hip power (O >Y; p = 0.04), and peak vertical ground reaction force (Y > O; p = 0.007). Regardless of age, participants exhibited decreased knee ROM (p = 0.007) and greater hip extension moment (p < 0.001) in C2 compared to C1.ConclusionWhile different in knee and hip mechanics overall, the subtle differences observed demonstrate that older runners exhibit comparable gait adaptions post-fatigue to younger volume-matched runners.     

The influence of maturation and sex on pelvis and hip kinematics in youth distance runners

ObjectivesThis study aimed to investigate differences in stance phase pelvic and hip running kinematics based on maturation and sex among healthy youth distance runners.DesignCross-Sectional.Methods133 uninjured youth distance runners (M = 60, F = 73; age = 13.5 ± 2.7 years) underwent a three-dimensional running analysis on a treadmill at a self-selected speed (2.8 ± 0.6 m·s^?1). Participants were stratified as pre-pubertal, mid-pubertal, or post-pubertal according to the modified Pubertal Maturational Observation Scale. Stance phase pelvis and hip range of motion (RoM) and peak joint positions were extracted. Two-way ANCOVAs (sex, maturation; covariate of running velocity) were used with Bonferroni-Holm method to control for multiple comparisons with a target alpha level of 0.05.ResultsA two-way interaction between sex and maturation was detected (p = 0.009) for frontal plane pelvic obliquity RoM. Post-hoc analysis identified a maturation main effect only among females (p?0.008). Pelvic obliquity RoM was significantly greater among post-pubertal (p = 0.001) compared to pre-pubertal females. Significant main effects of sex (p = 0.02), and maturation (p = 0.01) were found for hip adduction RoM. Post-hoc analysis indicated a significant increase in hip adduction RoM from pre-pubertal to post-pubertal female runners (p = 0.001). A significant main effect of sex was found for peak hip adduction angle (p = 0.001) with female runners exhibiting greater maximum peak hip adduction compared to males.ConclusionsMaturation influences pelvic and hip kinematics greater in female than male runners. Sex differences became more pronounced during later stages of puberty. These differences may correspond to an increased risk for running-related injuries in female runners compared to male runners.     

Chronic exercise preserves brain function in masters athletes when compared to sedentary counterparts

Objective: Exercise is beneficial for both the body and the mind, and it has been associated with protective neurocognitive effects, such as increased levels of brain-derived neurotrophic factor and neurogenesis. These effects are linked to the attenuation of age-related mental decline and the preservation of mental capacities in older, physically active adults. This study evaluated whether masters athletes, a highly active population, have better cognitive function compared to age-matched non-athletes based on the Immediate Post-concussion Assessment and Cognitive Testing (ImPACT) tool. Methods: Masters athletes and sedentary controls were recruited and screened for eligibility. All subjects were excluded if they had preexisting neurological diseases, psychiatric disorders, substance abuse disorders, learning disorders, and/or a history of traumatic brain injury, and in addition, control subjects were excluded if they performed >1 h/week of aerobic exercise. All participants completed a health and activity survey which includes the SF-12 and the ImPACT neurocognitive test which measures verbal and visual memory as well as reaction time. Differences between masters athletes and the control population were determined by ImPACT score composites. Results: 51 pairs of athletes and non-athletes were analyzed. Athletes had significantly higher verbal memory scores (85.9 ± 7.7 vs 79.9 ± 13.9, p = 0.01) and faster reaction times (0.71 ± 0.12 vs 0.76 ± 0.15 s, p = 0.04) on the ImPACT test. Athletes also scored significantly higher on the physical components summary score of the SF-12 (55.0 ± 3.3 vs 51.8 ± 6.7, p = 0.004). Conclusion: Masters athletes performed better on verbal memory and reaction time test, as well as on physical function as evaluated by the SF-12, compared to non-athlete controls. Chronic physical activity may preserve neurocognitive processes and increase physical health, which are protective factors for the negative effects of the aging process.     

Marked asymmetry in vertical force (but not contact times) during running in ACL reconstructed athletes <9 months post-surgery despite meeting functional criteria for return to sport.

Objectives

Compare maximum plantar force (Fmax) during running in soccer players following anterior cruciate ligament reconstruction (ACLR) as they pass return to sport (RTS) criteria.

Influence of speed and step frequency during walking and running on motion sensor output

PURPOSE: Studies have reported strong linear relationships between accelerometer output and walking/running speeds up to 10 km x h(-1). However, ActiGraph uniaxial accelerometer counts plateau at higher speeds. The aim of this study was to determine the relationships of triaxial accelerometry, uniaxial accelerometry, and pedometry with speed and step frequency (SF) across a range of walking and running speeds. METHODS: Nine male runners wore two ActiGraph uniaxial accelerometers, two RT3 triaxial accelerometers (all set at a 1-s epoch), and two Yamax pedometers. Each participant walked for 60 s at 4 and 6 km x h(-1), ran for 60 s at 10, 12, 14, 16, and 18 km x h(-1), and ran for 30 s at 20, 22, 24, and 26 km x h(-1). Step frequency was recorded by a visual count. RESULTS: ActiGraph counts peaked at 10 km x h(-10 (2.5-3.0 Hz SF) and declined thereafter (r=0.02, P>0.05). After correction for frequency-dependent filtering, output plateaued at 10 km x h(-1) but did not decline (r=0.77, P<0.05). Similarly, RT3 vertical counts plateaued at speeds > 10 km x h(-1) (r=0.86, P<0.01). RT3 vector magnitude and anteroposterior and mediolateral counts maintained a linear relationship with speed (r>0.96, P<0.001). Step frequency assessed by pedometry compared well with actual step frequency up to 20 km x h(-1) (approximately 3.5 Hz) but then underestimated actual steps (Yamax r=0.97; ActiGraph pedometer r=0.88, both P<0.001). CONCLUSION: Increasing underestimation of activity by the ActiGraph as speed increases is related to frequency-dependent filtering and assessment of acceleration in the vertical plane only. RT3 vector magnitude was strongly related to speed, reflecting the predominance of horizontal acceleration at higher speeds. These results indicate that high-intensity activity is underestimated by the ActiGraph, even after correction for frequency-dependent filtering, but not by the RT3. Pedometer output is highly correlated with step frequency.