Gait asymmetry in spatiotemporal and kinetic variables does not increase running-related injury risk in lower limbs: a secondary analysis of a randomised trial including 800+ recreational runners

Objective

To investigate asymmetry in spatiotemporal and kinetic variables in 800+ recreational runners, identify determinants of asymmetry, investigate if asymmetry is related to greater running injury risk and compare spatiotemporal and kinetic variables between the involved and uninvolved limb at baseline in runners having sustained an injury during follow-up.

Methods

836 healthy recreational runners (38.6% women) were tested on an instrumented treadmill at their preferred running speed at baseline and followed up for 6 months. From ground reaction force recordings, spatiotemporal and kinetic variables were derived for each lower limb. The Symmetry Index was computed for each variable. Correlations and multiple regression analyses were performed to identify potential determinants of asymmetry. Cox regression analyses investigated the association between asymmetry and injury risk. Analysis of variance for repeated measures was used to compare the involved and uninvolved limbs in runners who had sustained injuries during follow-up.

Results

107 participants reported at least one running-related injury. Leg length discrepancy and fat mass were the most common determinants of asymmetry, but all correlation coefficients were negligible (0.01-0.13) and explained variance was very low (multivariable-adjusted R2<0.01-0.03). Greater asymmetry for flight time and peak breaking force was associated with lower injury risk (HR (95% CI): 0.80 (0.64 to 0.99) and 0.96 (0.93 to 0.98), respectively). No between-limb differences were observed in runners having sustained an injury.

Conclusion

Gait asymmetry was not associated with higher injury risk for investigated spatiotemporal and kinetic variables.

Trial registration number

NCT03115437.

Impact of COVID-19 Vaccination on Short-Term Perceived Change in Physical Performance among Elite Athletes: An International Survey

COVID-19 vaccination raised concerns about its potential effects on physical performance. To assess the impact of COVID-19 vaccination on the perceived change in physical performance, we conducted an online survey among elite athletes from Belgium, Canada, France and Luxembourg, with questions about socio-demographics, COVID-19 vaccination, perceived impact on physical performance and perceived pressure to get vaccinated. Full vaccination was defined as two doses of mRNA or vector vaccine or a heterologous vaccine scheme. Among 1106 eligible athletes contacted, 306 athletes answered the survey and were included in this study. Of these, 72% perceived no change in their physical performance, 4% an improvement and 24% a negative impact following full COVID-19 vaccination. For 82% of the included athletes, the duration of the negative vaccine reactions was ≤3 days. After adjustment for potential confounding variables, practicing an individual sport, a duration of vaccine reactions longer than 3 days, a high level of vaccine reaction and the perceived pressure to get vaccinated were independently associated with a perceived negative impact on physical performance of more than 3 days after the vaccination. The perceived pressure to get vaccinated appears to be a parameter associated with the negative perceived change in the physical performance and deserves further consideration.

P07-07 Put the promotion of physical activity for people with non-communicable diseases on the political agenda in Luxembourg!

Issue/problem

In 1984, cardiologists and cardiac patients created an association offering physical activity (PA) for people with cardiovascular diseases in Luxembourg (0.6 million inhabitants). During the last 20 years, several associations created therapeutic PA for people with a wide range of non-communicable diseases (NCDs). Today more than 70 hours of therapeutic PA are weekly offered. Nevertheless, the organization of these PA is incomplete and not enough patients benefit from it.

Description of the problem

Sustainability of privately organized courses is challenging. Despite a governmental financial support, the organization of PA offer remains mainly based on the idealism of a limited number of volunteers. However, this kind of commitment is disappearing and jeopardizes a correct offer of therapeutic PA. Only a minority of physicians are referring their patients on a regular basis and only a minority of them are engaging in an active lifestyle.

Results

A project was launched in 2013 to compile, monitor and promote the therapeutic PA offered by different associations. As a result of this project, six associations created a sport federation in 2016 destined to improve the organization of therapeutic PA for people with NCDs. In 2018, the federation obtained an increase in the financial support from the Ministry of Health. The same year, a campaign promoted the therapeutic PA but had no impact on the number of patients counselled about therapeutic PA (26.6%) and on the physician's knowledge of the therapeutical PA offer (21%). The federation is now trying to develop and implement deeper actions, such as a PA referral scheme.

Lessons

The collaborative and synergetic work of the different associations offering PA for people with NCDs bundled their activities resulting in an increased consideration and support from the Ministry of Health. Nevertheless, structural improvements should be conducted to increase sustainably the number of physically active patients.

Main messages

Spatiotemporal and Ground-Reaction Force Characteristics as Risk Factors for Running-Related Injury: A Secondary Analysis of a Randomized Trial Including 800+ Recreational Runners

BACKGROUND

Running biomechanics may play a role in running-related injury development, but to date, only a few modifiable factors have been prospectively associated with injury risk.

PURPOSE

To identify risk factors among spatiotemporal and ground-reaction force characteristics in recreational runners and to investigate whether shoe cushioning modifies the association between running biomechanics and injury risk.

STUDY DESIGN

Case-control study; Level of evidence, 3.

METHODS

Recreational runners (N = 848) were tested on an instrumented treadmill at their preferred running speed in randomly allocated, standardized running shoes (with either hard or soft cushioning). Typical kinetic and spatiotemporal metrics were derived from ground-reaction force recordings. Participants were subsequently followed up for 6 months regarding running activity and injury. Cox regression models for competing risk were used to investigate the association between biomechanical risk factors and injury risk, including stratified analyses by shoe version.

RESULTS

In the crude analysis, greater injury risk was found for greater step length (subhazard rate ratio [SHR], 1.01; 95% CI, 1.00-1.02; P = .038), longer flight time (SHR, 1.00; 95% CI, 1.00-1.01; P = .028), shorter contact time (SHR, 0.99; 95% CI, 0.99-1.00; P = .030), and lower duty factor (defined as the ratio between contact time and stride time; SHR, 0.95; 95% CI, 0.91-0.98; P = .005). In the stratified analyses by shoe version, adjusted for previous injury and running speed, lower duty factor was associated with greater injury risk in those using the soft shoes (SHR, 0.92; 95% CI, 0.85-0.99; P = .042) but not in those using the hard shoes (SHR, 0.97; 95% CI, 0.91-1.04; P = .348).

CONCLUSION

Lower duty factor is an injury risk factor, especially for softer shoe use. Contrary to widespread beliefs, vertical impact peak, loading rate, and step rate were not injury risk factors in recreational runners.

REGISTRATION

NCT03115437 (ClinicalTrials.gov identifier).

Exercise-Based Injury Prevention in High-Level and Professional Athletes: Narrative Review and Proposed Standard Operating Procedure for Future Lockdown-Like Contexts After COVID-19

In regular times, implementing exercise-based injury prevention programs into the training routine of high-level and professional athletes represents a key and challenging aspect to decrease injury risk. Barriers to implementing such prevention programs have previously been identified such as lack of resources, logistic issues or motivation. The COVID-19 pandemic associated with restrictions on daily life dramatically impacted sports participation from training to competition. It is therefore reasonable to assume that such lockdown-like context has exacerbated the challenge to implement exercise-based injury prevention programs, potentially leading to a greater musculoskeletal injury risk. In this narrative review, recommendations are proposed for building an expertise- and evidence-based Standard Operating Procedure for injury prevention in lockdown-like contexts for high-level and professional athletes. The following recommendations can be provided: (1) assess the global and sport-specific risks in the light of the ongoing cause of isolation; (2) adapt remote training materials and programs; (3) ensure regular quality communication within the staff, between athletes and the staff as well as between athletes; (4) follow the athlete's mental well-being; and (5) plan for a safe return-to-sports as well as for an ongoing monitoring of the load-recovery balance. These key domains should further be addressed to comply with local policies, which are subject to change over time in each individual country. The use of these recommendations may improve the readiness of athletes, coaches, physicians and all sports stakeholders for future lockdown-like contexts.

Effect of shoe cushioning on landing impact forces and spatiotemporal parameters during running: results from a randomized trial including 800+ recreational runners

AbstractIn a recent randomized trial including 800+ recreational runners, injury risk was lower in those who received the Soft shoe version compared to those using the Hard version (Hazard ratio = 1.52; 95% Confidence Interval = 1.07-2.16). Here, we investigated the effect of shoe cushioning on ground reaction forces (GRF) and spatiotemporal parameters in the same cohort, with a special focus on Vertical Impact Peak Force (VIPF) and Vertical Instantaneous Loading Rate (VILR). Healthy runners (n = 848) randomly received one of two shoe prototypes that differed only in their cushioning properties (Global stiffness: 61 ± 3 and 95 ± 6 N/mm in the Soft and Hard versions, respectively). Participants were tested on an instrumented treadmill at their preferred running speed. GRF data was recorded over 2 min. VIPF was higher in the Soft shoe group compared to the Hard shoe group (1.53 ± 0.21 vs. 1.44 ± 0.23 BW, respectively; p < 0.001). However, the proportion of steps with detectable VIPF was lower in the Soft shoe group (84 vs. 97%, respectively; p < 0.001) and Time to VIPF was longer (46.9 ± 8.5 vs. 43.4 ± 7.4 milliseconds, respectively; p < 0.001). No significant differences were observed for VILR (60.1 ± 13.8 vs. 58.9 ± 15.6 BW/s for Soft and Hard shoe group, respectively; p = 0.070) or any other kinetic variable. These results show that the beneficial effect of greater shoe cushioning on injury risk in the present cohort is not associated with attenuated VIPF and VILR. These GRF metrics may be inappropriate markers of the shoe cushioning-injury risk relationship, while delayed VIPF and the proportion of steps displaying a VIPF could be more relevant.Trial registration: ClinicalTrials.gov identifier: NCT03115437..

Shoe Cushioning Influences the Running Injury Risk According to Body Mass: A Randomized Controlled Trial Involving 848 Recreational Runners

BACKGROUND

Shoe cushioning is expected to protect runners against repetitive loading of the musculoskeletal system and therefore running-related injuries. Also, it is a common belief that heavier runners should use footwear with increased shock absorption properties to prevent injuries.

PURPOSE

The aim of this study was to determine if shoe cushioning influences the injury risk in recreational runners and whether the association depends on the runner's body mass.

STUDY DESIGN

Randomized controlled trial; Level of evidence, 1.

METHODS

Healthy runners (n = 848) randomly received 1 of 2 shoe prototypes that only differed in their cushioning properties. Global stiffness was 61.3 ± 2.7 and 94.9 ± 5.9 N/mm in the soft and hard versions, respectively. Participants were classified as light or heavy according to their body mass using the median as a cut-off (78.2 and 62.8 kg in male and female runners, respectively). They were followed over 6 months regarding running activity and injury (any physical complaint reducing/interrupting running activity for at least 7 days). Data were analyzed through time-to-event models with the subhazard rate ratio (SHR) and their 95% confidence interval (CI) as measures of association. A stratified analysis was conducted to investigate the effect of shoe cushioning on the injury risk in lighter and heavier runners.

RESULTS

The runners who had received the hard shoes had a higher injury risk (SHR, 1.52 [95% CI, 1.07-2.16]), while body mass was not associated with the injury risk (SHR, 1.00 [95% CI, 0.99-1.01]). However, after stratification according to body mass, results showed that lighter runners had a higher injury risk in hard shoes (SHR, 1.80 [95% CI, 1.09-2.98]) while heavier runners did not (SHR, 1.23 [95% CI, 0.75-2.03]).

CONCLUSION

The injury risk was higher in participants running in the hard shoes compared with those using the soft shoes. However, the relative protective effect of greater shoe cushioning was found only in lighter runners.

REGISTRATION

NCT03115437 (ClinicalTrials.gov identifier).

Motivational Interviewing to Increase Physical Activity Behavior in Cancer Patients: A Pilot Randomized Controlled Trials

OBJECTIVE

This pilot randomized controlled trial (RCT) aimed at evaluating the feasibility and potential efficacy of a motivational interviewing (MI) intervention to increase physical activity (PA) behavior in cancer patients.

METHODS

Participants were randomly assigned to an experimental group with standard care plus 12 MI sessions within 12 weeks or a control group with standard care only. The number of recruited participants and the modality of recruitment were recorded to describe the reach of the study. The acceptability of the study was estimated using the attrition rate during the intervention phase. The potential efficacy of the intervention was evaluated by analyzing the PA behavior.

RESULTS

Twenty-five participants were recruited within the 16-month recruitment period (1.6 participants per month). Five participants (38.5%) from the experimental group (n = 13) and one participant (8.3%) from the control group (n = 12) dropped out of the study before the end of the intervention phase. No group by time interaction effect for PA behavior was observed at the end of the intervention.

CONCLUSION

Due to the low recruitment rate and compliance, no conclusion can be drawn regarding the efficacy of MI to increase PA behavior in cancer patients. Moreover, the current literature cannot provide any evidence on the effectiveness of MI to increase PA in cancer survivors. Future RCTs should consider that the percentage of uninterested patients to join the study may be as high as 60%. Overrecruitment (30% to 40%) is also recommended to accommodate the elevated attrition rate.

Influence of sports flooring and shoes on impact forces and performance during jump tasks

We aim to determine the influence of sports floorings and sports shoes on impact mechanics and performance during standardised jump tasks. Twenty-one male volunteers performed ankle jumps (four consecutive maximal bounds with very dynamic ankle movements) and multi-jumps (two consecutive maximal counter-movement jumps) on force plates using minimalist and cushioned shoes under 5 sports flooring (SF) conditions. The shock absorption properties of the SF, defined as the proportion of peak impact force absorbed by the tested flooring when compared with a concrete hard surface, were: SF0 = 0% (no flooring), SF1 = 19%, SF2 = 26%, SF3 = 37% and SF4 = 45%. Shoe and flooring effects were compared using 2x5 repeated-measures ANOVA with post-hoc Bonferroni-corrected comparisons. A significant interaction between SF and shoe conditions was found for VILR only (p = 0.003). In minimalist shoes, SF influenced Vertical Instantaneous Loading Rate (VILR) during ankle jumps (p = 0.006) and multi-jumps (p<0.001), in accordance with shock absorption properties. However, in cushioned shoes, SF influenced VILR during ankle jumps only (p<0.001). Contact Time was the only additional variable affected by SF, but only during multi-jumps in minimalist shoes (p = 0.037). Cushioned shoes induced lower VILR (p<0.001) and lower Contact Time (p≤0.002) during ankle jumps and multi-jumps compared to minimalist shoes. During ankle jumps, cushioned shoes induced greater Peak Vertical Ground Reaction Force (PVGRF, p = 0.002), greater Vertical Average Loading Rate (p<0.001), and lower eccentric (p = 0.008) and concentric (p = 0.004) work. During multi-jumps, PVGRF was lower (p<0.001) and jump height was higher (p<0.001) in cushioned compared to minimalist shoes. In conclusion, cushioning influenced impact forces during standardised jump tasks, whether it was provided by the shoes or the sports flooring. VILR is the variable that was the most affected.

Shoe cushioning, body mass and running biomechanics as risk factors for running injury: a study protocol for a randomised controlled trial

INTRODUCTION

Repetitive loading of the musculoskeletal system is suggested to be involved in the underlying mechanism of the majority of running-related injuries (RRIs). Accordingly, heavier runners are assumed to be at a higher risk of RRI. The cushioning system of modern running shoes is expected to protect runners again high impact forces, and therefore, RRI. However, the role of shoe cushioning in injury prevention remains unclear. The main aim of this study is to investigate the influence of shoe cushioning and body mass on RRI risk, while exploring simultaneously the association between running technique and RRI risk.

METHODS AND ANALYSIS

This double-blinded randomised controlled trial will involve about 800 healthy leisure-time runners. They will randomly receive one of two running shoe models that will differ in their cushioning properties (ie, stiffness) by ~35%. The participants will perform a running test on an instrumented treadmill at their preferred running speed at baseline. Then they will be followed up prospectively over a 6-month period, during which they will self-report all their sports activities as well as any injury in an internet-based database TIPPS (Training and Injury Prevention Platform for Sports). Cox regression analyses will be used to compare injury risk between the study groups and to investigate the association among training, biomechanical and anatomical risk factors, and injury risk.

ETHICS AND DISSEMINATION

The study was approved by the National Ethics Committee for Research (Ref: 201701/02 v1.1). Outcomes will be disseminated through publications in peer-reviewed journals, presentations at international conferences, as well as articles in popular magazines and on specialised websites.

TRIAL REGISTRATION NUMBER

NCT03115437, Pre-results.

Effect of Promotional Initiatives on Visits to a Dedicated Website for Physical Activity and Non-Communicable Disease in Luxembourg: An Event Study

The Sport-Santé project and its website (www.sport-sante.lu) promote physical activity for individuals with non-communicable diseases (NCDs) in Luxembourg. Our purpose was to perform an event study analysis to evaluate the effects of communication and promotional initiatives on the number of visits to the Sport-Santé website. Between September 2015 and May 2016, the Sport-Santé website was promoted during different initiatives, including participation in health-related events or publication of articles in local journals. The daily number of visits to www.sport-sante.lu website (i.e., our outcome) was recorded using Google Analytics and compared to a counterfactual collected with its benchmarking tool. The counterfactual was defined as the daily number of visits to websites in the same field. A model was created to evaluate the relationship between the number of visits to www.sport-sante.lu website and the number of visits to similar websites during a control period with no promotional initiatives (from July 2015 to September 2015). The effect of promotional initiatives was subsequently tested, by comparing the actual number of visits to our website (up to 2 days after each event) with the theoretical number of visits predicted by the model. Twenty-two initiatives were identified, of which 11 were participations at major health-related events and 11 publications of popular science articles. Of these 22 initiatives, the event study identified 2 popular science articles and 1 interactive workshop that significantly increased the daily number of visits to the www.sport-sante.lu website. One of the two articles was published on the day before the workshop was held, which did not allow us to distinguish its specific impact. The second article was published in the main national newspaper. This is the first time to our knowledge that an event study analysis has been used to evaluate the impact of promotional initiatives on the number of visits to a dedicated website for physical activity and NCDs. Our results indicate that some initiatives can aid in the number of visits, but in general their impact is limited. To observe an increased rate of participation in physical activity, additional promotional and evaluative strategies should be explored.

Influence of the Heel-to-Toe Drop of Standard Cushioned Running Shoes on Injury Risk in Leisure-Time Runners: A Randomized Controlled Trial With 6-Month Follow-up

BACKGROUND

Modern running shoes are available in a wide range of heel-to-toe drops (ie, the height difference between the forward and rear parts of the inside of the shoe). While shoe drop has been shown to influence strike pattern, its effect on injury risk has never been investigated. Therefore, the reasons for such variety in this parameter are unclear.

PURPOSE

The first aim of this study was to determine whether the drop of standard cushioned running shoes influences running injury risk. The secondary aim was to investigate whether recent running regularity modifies the relationship between shoe drop and injury risk.

STUDY DESIGN

Randomized controlled trial; Level of evidence, 1.

METHODS

Leisure-time runners (N = 553) were observed for 6 months after having received a pair of shoes with a heel-to-toe drop of 10 mm (D10), 6 mm (D6), or 0 mm (D0). All participants reported their running activities and injuries (time-loss definition, at least 1 day) in an electronic system. Cox regression analyses were used to compare injury risk between the 3 groups based on hazard rate ratios (HRs) and their 95% CIs. A stratified analysis was conducted to evaluate the effect of shoe drop in occasional runners (<6 months of weekly practice over the previous 12 months) versus regular runners (≥6 months).

RESULTS

The overall injury risk was not different among the participants who had received the D6 (HR, 1.30; 95% CI, 0.86-1.98) or D0 (HR, 1.17; 95% CI, 0.76-1.80) versions compared with the D10 shoes. After stratification according to running regularity, low-drop shoes (D6 and D0) were found to be associated with a lower injury risk in occasional runners (HR, 0.48; 95% CI, 0.23-0.98), whereas these shoes were associated with a higher injury risk in regular runners (HR, 1.67; 95% CI, 1.07-2.62).

CONCLUSION

Overall, injury risk was not modified by the drop of standard cushioned running shoes. However, low-drop shoes could be more hazardous for regular runners, while these shoes seem to be preferable for occasional runners to limit injury risk.

Recommendations for participation in competitive sport and leisure-time physical activity in individuals with cardiomyopathies, myocarditis and pericarditis

Several relatively uncommon, but important cardiovascular diseases are associated with increased risk for acute cardiac events during exercise (including sudden death), such as hypertrophic cardiomyopathy (HCM), dilated cardiomyopathy (DCM), arrhythmogenic right ventricular cardiomyopathy (ARVC) and myo-pericarditis. Practising cardiologists are frequently asked to advise on exercise programmes and sport participation in young individuals with these cardiovascular diseases. Indeed, many asymptomatic (or mildly symptomatic) patients with cardiomyopathies aspire to a physically active lifestyle to take advantage of the many documented benefits of exercise. While recommendations dictating the participation in competitive sport for athletes with cardiomyopathies and myo-pericarditis have recently been published as a consensus document of the European Society of Cardiology, no European guidelines have addressed the possible participation of patients with cardiomyopathies in recreational and amateur sport activities. The present document is intended to offer a comprehensive overview to practising cardiologists and sport physicians of the recommendations governing safe participation in different types of competitive sport, as well as the participation in a variety of recreational physical activities and amateur sports in individuals with cardiomyopathies and myo-pericarditis. These recommendations, based largely on the experience and insights of the expert panel appointed by the European Society of Cardiology, include the most up-to-date information concerning regular exercise and sports activity in patients with cardiomyopathies and myo-pericarditis.

Does cumulating endurance training at the weekends impair training effectiveness?

BACKGROUND

Due to occupational restrictions many people's recreational endurance activities are confined to the weekends. We intended to clarify if cumulating the training load in such a way diminishes endurance gains.

DESIGN

We conducted a longitudinal study comparing training-induced changes within three independent samples.

METHODS

Thirty-eight healthy untrained participants (45+/-8 years, 80+/-18 kg; 172+/-9 cm) were stratified for endurance capacity and sex and randomly assigned to three groups: 'weekend warrior' (n=13, two sessions per week on consecutive days, 75 min each, intensity 90% of the anaerobic threshold; baseline lactate+1.5 mmol/l), regular training (n=12, five sessions per week, 30 min each, same intensity as weekend warrior), and control (n=13, no training). Training was conducted over 12 weeks and monitored by means of heart rate. Identical graded treadmill protocols before and after the training program served for exercise prescription and assessment of endurance effects.

RESULTS

VO2max improved similarly in weekend warrior (+3.4 ml/min per kg) and register training (+1.5 ml/min per kg; P=0.20 between groups). Compared with controls (-1.0 ml/min per kg) this effect was significant for weekend warriors (P<0.01) whereas there was only a tendency for the regular training group (P=0.10). In comparison with controls (mean decrease, 3 beats/min), the average heart rate during exercise decreased significantly by 11 beats/min (weekend warriors, P<0.01) and 9 beats/min (regular training, P<0.05). There was no significant difference, however, between the weekend warrior and regular training groups (P=0.99).

CONCLUSION

In a middle-aged population of healthy untrained subjects, cumulating the training load at the weekends does not lead to an impairment of endurance gains in comparison with a smoother training distribution.

Plantar pressure measurements and running-related injury: A systematic review of methods and possible associations

Pressure-sensitive measuring devices have been identified as appropriate tools for measuring an array of parameters during running. It is unclear which biomechanical characteristics relate to running-related injury (RRI) and which data-processing techniques are most promising to detect this relationship. This systematic review aims to identify pertinent methodologies and characteristics measured using plantar pressure devices, and to summarise their associations with RRI. PubMed, Embase, CINAHL, ScienceDirect and Scopus were searched up until March 2015. Retrospective and prospective, biomechanical studies on running using any kind of pressure-sensitive device with RRI as an outcome were included. All studies involving regular or recreational runners were considered. The study quality was assessed and the measured parameters were summarised. One low quality, two moderate quality and five high quality studies were included. Five different subdivisions of plantar area were identified, as well as five instants and four phases of measurement during foot-ground contact. Overall many parameters were collated and subdivided as plantar pressure and force, plantar pressure and force location, contact area, timing and stride parameters. Differences between the injured and control group were found for mediolateral and anteroposterior displacement of force, contact area, velocity of force displacement, relative force-time integral, mediolateral force ratio, time to peak force and inter-stride correlative patterns. However, no consistent results were found between studies and no biomechanical risk patterns were apparent. Additionally, conflicting findings were reported for peak force in three studies. Based on these observations, we provide suggestions for improved methodology measurement of pertinent parameters for future studies.

Injury risk in runners using standard or motion control shoes: a randomised controlled trial with participant and assessor blinding

Background/aim

This randomised controlled trial investigated if the usage of running shoes with a motion control system modifies injury risk in regular leisure-time runners compared to standard shoes, and if this influence depends on foot morphology.

Methods

Recreational runners (n=372) were given either the motion control or the standard version of a regular running shoe model and were followed up for 6 months regarding running activity and injury. Foot morphology was analysed using the Foot Posture Index method. Cox regression analyses were used to compare injury risk between the two groups, based on HRs and their 95% CIs, controlling for potential confounders. Stratified analyses were conducted to evaluate the effect of motion control system in runners with supinated, neutral and pronated feet.

Results

The overall injury risk was lower among the participants who had received motion control shoes (HR=0.55; 95% CI 0.36 to 0.85) compared to those receiving standard shoes. This positive effect was only observed in the stratum of runners with pronated feet (n=94; HR=0.34; 95% CI 0.13 to 0.84); there was no difference in runners with neutral (n=218; HR=0.78; 95% CI 0.44 to 1.37) or supinated feet (n=60; HR=0.59; 95% CI 0.20 to 1.73). Runners with pronated feet using standard shoes had a higher injury risk compared to those with neutral feet (HR=1.80; 95% CI 1.01 to 3.22).

Conclusions

The overall injury risk was lower in participants who had received motion control shoes. Based on secondary analysis, those with pronated feet may benefit most from this shoe type.

Promotion of physical activity in patients with non-communicable diseases in Luxembourg: a follow-up of the Sport-Sante inventory from 2014

Regular practice of physical activity (PA) has many health benefits in both healthy individuals and in people with non-communicable diseases (NCDs). In order to disseminate this evidence and to strengthen the promotion of PA in people with NCDs, the Sport-Santé project was created in Luxembourg and officially launched in April 2015. In 2014, a stocktaking of the different organizations offering PA for people with NCDs was realized in order to develop the Sport-Santé project. Different communication tools were used to promote Sport-Santé as well as the aforementioned organizations. The present study aimed to re-evaluate the offers of PA for people with NCDs in Luxembourg one year after the launch of the project. The organizations offering PA for people with NCDs (orthopaedics, obesity and overweight, neurology and rare diseases, oncology and cardiology) were screened in 2014 and in 2016. The number of weekly offered hours of PA for people with NCDs were collected and the participation rate was observed. Participants (192 in 2014 and 196 in 2016) volunteered to answer a survey, which contained questions regarding their age, sex, time since enrolment, travel distance, former and current PA participation, and type of recruitment. Additional items regarding prescription and refund were explored only in 2016. In 2016, more than 55 hours per week of PA were offered for people with NCDs in Luxembourg (≈44 hours per week were identified in 2014). However, this increase was not statistically significant. No difference was observed between 2014 and 2016 regarding the participation rate (2014: 8.9 ± 5.1 participants per hour; 2016: 8.4 ± 5.7 participants per hour). Participants were younger in 2016 than in 2014. The time since enrolment was shorter in 2016 than in 2014. No difference between 2014 and 2016 was observed for travel distance, sex distribution, former and current PA participation, and type of recruitment. Participants were mainly recruited by the healthcare professionals. More than 69 % of the participants would like to receive a medical prescription for the PA. Fifty-two percent of the participants would appreciate a refund of the participation fees by their health insurance. The increasing efforts of Sport-Santé and the organizations offering PA for people with NCDs lead to increase the offer. However, the participation rate remains unchanged. The decrease in age and in time since enrolment observed in 2016 could be explained by the creation of new activities, a larger participant's turnover or high number of withdrawals among long-term participants. Even if participants are mainly recruited by healthcare professionals, this type of recruitment can be attributed to very few idealists. All healthcare professionals should be aware of the offers of Sport-Santé and advise their patients to participate in a PA program. It is now time to advance the idea of prescription of PA as a privileged treatment option and to convince the policymakers to take action against sedentary behaviours in Luxembourg. Nevertheless, this type of promotion is not enough to increase the number of participants and additional strategies must be explored and developed. The best sustainable strategies are always those that approach the problem from different viewpoints.

The effect of shoe type and fatigue on strike index and spatiotemporal parameters of running

We aimed to observe differences in running style parameters and the stride-to-stride coefficient of variation and correlative patterns using detrended fluctuation analysis (DFA) between conventional and first-time minimalistic shoe use. We also aimed to study the effect of fatigue on these parameters. 26 recreational runners were tested using a pressure insole device on a treadmill whilst wearing conventional (CONV) and minimalistic (MIN) shoes. They then performed a prolonged running bout simulating a fatiguing training session, before being tested a second time in both shoe types. Average values of strike index (initial ground contact point on the footsole expressed as a percentage of total sole length) were not significantly different between CONV [25.7±14.6% (unfatigued), 23.1±11.1% (fatigued)] and MIN [28.9±19.1% (unfatigued), 26.7±17.6% (fatigued)] (p=0.501). The fatigued state also yielded a similar strike index compared to the unfatigued state (p=0.661). An overall trend in decreased inter-stride correlative patterns of strike index was observed in MIN compared to CONV (p=0.075). No differences in contact time, flight time, stride time, duty factor, stride length and stride frequency were found between shoe types. A trend in reduced flight time (p=0.078) and therefore increased duty factor (p=0.053) was observed due to fatigue. We conclude that in recreational runners, no meaningful, acute adaptation in running style occurs as a result of first-time MIN use. Similarly, runners were able to maintain their running style after a prolonged running bout.

Association of previous injury and speed with running style and stride-to-stride fluctuations

Running-related injuries remain problematic among recreational runners. We evaluated the association between having sustained a recent running-related injury and speed, and the strike index (a measure of footstrike pattern, SI) and spatiotemporal parameters of running. Forty-four previously injured and 46 previously uninjured runners underwent treadmill running at 80%, 90%, 100%, 110%, and 120% of their preferred running speed. Participants wore a pressure insole device to measure SI, temporal parameters, and stride length (S(length)) and stride frequency (S(frequency)) over 2-min intervals. Coefficient of variation and detrended fluctuation analysis provided information on stride-to-stride variability and correlative patterns. Linear mixed models were used to compare differences between groups and changes with speed. Previously injured runners displayed significantly higher stride-to-stride correlations of SI than controls (P = 0.046). As speed increased, SI, contact time (T(contact)), stride time (T(stride)), and duty factor (DF) decreased (P < 0.001), whereas flight time (T(flight)), S(length), and S(frequency) increased (P < 0.001). Stride-to-stride variability decreased significantly for SI, T(contact), T(flight), and DF (P ≤ 0.005), as did correlative patterns for T(contact), T(stride), DF, S(length), and S(frequency) (P ≤ 0.044). Previous running-related injury was associated with less stride-to-stride randomness of footstrike pattern. Overall, runners became more pronounced rearfoot strikers as running speed increased.

Moderate to severe injuries in football: a one-year prospective study of twenty-four female and male amateur teams

This study aimed to realize a prospective follow-up of the injuries occurring in female and male football players involved in the highest league in the Grand-Duchy of Luxembourg. Data concerning anthropometric characteristics and football activities were gathered in 125 female and 243 male football players via questionnaires at the beginning of the study. Then, a follow-up of moderate to severe injuries (> 15 days of interruption in football practice) was performed throughout the season 2013-2014. Sixteen injuries (injury incidence = 0.7 injuries/1000 h of exposure) were observed in 13 female football players (10.4%). These injuries concerned mainly the knee (n = 7; 43.7%), with capsules and ligaments being the most often concerned tissues (n = 7; 43.7%). In male football players, 41 severe injuries (injury incidence = 0.6 injuries/1000 h of exposure) were observed in 36 players (14.8%). These injuries concerned mainly the thighs (n = 12; 29.3%) and the muscles and tendons were the most often concerned tissues (n = 18; 43.9%). Injuries in football are predominantly located at the lower limbs, particularly the knees in female football players. The predominant muscle and tendon lesions of the thighs occurring in males could reveal that physical preparation is insufficient or inadequate for a number of players. Regarding these results, it is necessary to implement an injury prevention strategy. The "FIFA 11+" programme could be used as the basic method, but should be personalized according to sex. The injury collection methodology could be optimized with the use of an electronic database, such as the Training and Injury Prevention Platform for Sports (TIPPS). Beside the systematic recording of injury data (as well as the training load) by the players or the medical staff, this system allows to share of important information between stakeholders, follow-up the players, provide risk factor warnings and increase the awareness of the injury problem.

Ergometric performance and cardiovascular profile of obesity clinic patients

BACKGROUND

Aerobic exercise capacity is considered as an independent prognostic factor for cardiovascular disease and mortality. It is usually expressed in maximal oxygen consumption (VO2(max)) or metabolic equivalent (MET) and is measured by spiroergometry or calculated by a regression formula based on maximal performance achieved. Obesity is associated with reduced physical performance and increased cardiovascular mortality. The aim of our study was to describe the ergometric and cardiovascular profile of patients of an obesity clinic, and to compare a direct measure of VO2(max) with an indirect by a regression formula and to.

METHOD

131 consecutive patients of an obesity clinic (95 females, 36 males) aged 16-75 years participated. The VO2(max) was measured by spiro-ergometry on a treadmill and estimated by a regression formula on the basis of the speed and grade of the treadmill. We have determined the relationship between Body mass index (BMI), Waist Circumference (WC) and the parameters VO2(max)/kg, MET, Performance Relative for Age, Heart Rate Recovery one minute after maximal effort (HRR), VO2(max) relative to a theoretical normal body weight (corresponding to a BMI of 25 kg/m2 (VO2(max)Rel25)), blood pressure, at rest and 5 minutes after exercise, Framingham Score and C-reactive protein (CRP).

RESULTS

For the different age groups the VO2(max)/kg was below normal values (mean -23.4%). Measured VO2(max) was 15.2% lower than estimated by the regression formula. After adjusting to age and to a theoretical upper-limit normal body weight (corresponding to a BMI of 25 kg/m2) VO2(max)/kg was 5-20% (mean value 15%) higher than the reference values. VO2(max)/kg and HRR were correlated with BMI, WC and Framingham Score. 40% of the patients were already treated for hypertension, 55% had elevated blood pressure measurements at rest and 52% after exercise.

CONCLUSIONS

Ergometric stress testing in obese subjects delivers important information that helps to evaluate the cardiovascular risk in this population and to provide individual recommendations for training therapy (e.g. training intensity, heart rate etc). Obese patients show a marked diminution of aerobic exercise capacity. In this population, the use of a standard regression formula to calculate VO2(max) leads to an overestimation of aerobic performance. The even higher than normal VO2(max) related to upper-normal body weight indicates that the reduced physical performance in obese patients is rather due to the overweight than to a pathological loss of muscle mass.

[Promotion of physical activity for secondary prevention in patients with chronic diseases: the situation in the Grand-Duchy of Luxembourg]

The regular practice of physical activities has health benefits in healthy subjects (primary prevention) and in patients with non-communicable diseases (secondary prevention). This study aimed to perform a stocktaking of the physical activities programs for patients or individuals at risk in the Grand-Duchy of Luxembourg. The organizations offering therapeutic physical activities (TPA) have been investigated. Eleven groups offering TPA adapted to different non-communicable diseases were characterized by their costs, instructors, participants and potential participants. These groups were divided into five main categories: cardiology, neurology, obesity, oncology, and orthopedics. During on-site meetings, 41 professionals, 192 participants and 34 potential participants have been interviewed during the period September 2013 to April 2014. The results show that about 40 hours of TPA, 17 hours of which in cardiology, are currently proposed every week, except during school holidays. The main TPA are gymnastics, aerobics, swimming, Nordic walking, cycling, and resistance training. The national coverage is quite low, especially for obesity, neurology and orthopedics. The costs is mainly related to the human resources, the gym being often borrowed but rarely available during school holidays. Between 200 and 400 individuals participate in the TPA. The average number of participants per hour is 8.9 (± 5.1), which represents only 50% of the maximal capacity estimated by the instructors (18.0 ± 8.2 participants per hour). The recruitment process is different according to the groups but the medical doctors and the physiotherapists are mainly involved in this process. However, the majority of the potential participants were not aware of the existence of the groups. The existence of these groups is a positive point, since it contributes to compensate for the current lack of concrete action of the public and private authorities. However, the current TPA offer is clearly insufficient. The groups are frail, on the one hand because their future relies exclusively upon the idealism of a few key actors, and on the other hand because the participation rate is low. This low rate is related to a lack of information and to organizational constraints. However, the public health action initiated by these groups should be perpetuated and strengthened with a better structuration and professionalization. Finally, the increase of the number of participants remains the main objective.

Injury incidence in a sports school during a 3-year follow-up

PURPOSE

This study prospectively analysed sports injury incidence over 3 seasons in a regional sports school within an injury surveillance project, involving 372 athletes (12-19 years) from 16 different disciplines.

METHODS

A personal sports diary was used to record all sporting activities daily for every athlete. Injuries (time-loss definition) were registered via a standardized questionnaire.

RESULTS

Sports injury incidence (injuries/1,000 h) evolved from 3.9 in the first year to 4.8 in the second (p < 0.01) and down to 2.8 in the third (p < 0.001, compared to the preceding periods). Significant decreases of injury incidence in the third year were also observed when classifying injuries as traumatic or overuse, and as new or recurrent. The proportion of recurrent injuries was lower in the third period (11 %) when compared to the first (19.5 %, p < 0.05) and the second one (26.3 %, p < 0.05). Injury incidence was lowest during the third period for all severity categories. The same was found when considering injuries within racket, team and individual sports.

CONCLUSIONS

Implementing an injury surveillance system in this setting was associated with a lower injury incidence in the third observation period. This project may have influenced stakeholders' awareness and attitude towards the sports injury problematic.

Influence of midsole hardness of standard cushioned shoes on running-related injury risk

BACKGROUND

In this double-blind randomised controlled trial, we tested if leisure-time runners using shoes with less compliant midsoles have a higher running-related injury (RRI) risk.

METHOD

We provided 247 runners with standard running shoes having either a soft study shoes (soft-SS) or a hard study shoes (hard-SS) midsole and followed them prospectively for 5 months regarding RRI. All information about sports practice and injuries was uploaded on a dedicated internet platform and checked for consistency and completeness. RRI was defined as any first-time pain sustained during or as a result of running practice and impeding normal running activity for at least 1 day. Cox proportional hazards regressions were used to identify RRI risk factors.

RESULT

The type of study shoes used for running was not associated with RRIs (HR=0.92; 95% CI 0.57 to 1.48). The hard-SS had a 15% greater overall stiffness in the heel region. The two study groups were similar regarding personal and sports participation characteristics, except for years of running experience, which was higher (p<0.05) in the hard-SS group. Global RRI incidence was 12.1 RRI/1000 h of running. No between-group differences were found regarding injury location, type, severity or category. Nevertheless, the adjusted regression model revealed positive associations with RRI risk for body mass index (HR=1.126; 95% CI 1.033 to 1.227), previous injury (HR=1.735; 95% CI 1.037 to 2.902) and mean session intensity (HR=1.396; 95% CI 1.040 to 1.874). Protective factors were previous regular running activity (HR=0.422; 95% CI 0.228 to 0.779) and weekly volume of other sports activities (HR=0.702; 95% CI 0.561 to 0.879).

CONCLUSIONS

Midsole hardness of modern cushioned running shoes does not seem to influence RRI risk.

Reliability and validity of pressure and temporal parameters recorded using a pressure-sensitive insole during running

Running biomechanics has received increasing interest in recent literature on running-related injuries, calling for new, portable methods for large-scale measurements. Our aims were to define running strike pattern based on output of a new pressure-sensitive measurement device, the Runalyser, and to test its validity regarding temporal parameters describing running gait. Furthermore, reliability of the Runalyser measurements was evaluated, as well as its ability to discriminate different running styles. Thirty-one healthy participants (30.3 ± 7.4 years, 1.78 ± 0.10 m and 74.1 ± 12.1 kg) were involved in the different study parts. Eleven participants were instructed to use a rearfoot (RFS), midfoot (MFS) and forefoot (FFS) strike pattern while running on a treadmill. Strike pattern was subsequently defined using a linear regression (R(2)=0.89) between foot strike angle, as determined by motion analysis (1000 Hz), and strike index (SI, point of contact on the foot sole, as a percentage of foot sole length), as measured by the Runalyser. MFS was defined by the 95% confidence interval of the intercept (SI=43.9-49.1%). High agreement (overall mean difference 1.2%) was found between stance time, flight time, stride time and duty factor as determined by the Runalyser and a force-measuring treadmill (n=16 participants). Measurements of the two devices were highly correlated (R ≥ 0.80) and not significantly different. Test-retest intra-class correlation coefficients for all parameters were ≥ 0.94 (n=14 participants). Significant differences (p<0.05) between FFS, RFS and habitual running were detected regarding SI, stance time and stride time (n=24 participants). The Runalyser is suitable for, and easily applicable in large-scale studies on running biomechanics.

Complete inclusion of adaptive rowing only 1000 m ahead

Adaptive rowing (AR) at the Paralympic level is accessible for rowers with physical disability. AR was included for the first time in the Beijing 2008 Paralympic Games. Racing distance for all AR events is currently 1000 m, which impedes public recognition of this sport and leads to many organisational challenges during the inclusive World Rowing Championships. The aim of this report was to discuss the feasibility of increasing AR race distance to 2000 m from a sports injury and athletic health perspective. As limited data on injury and illness risks exist in AR, knowledge and experiences had to be taken from other Paralympic sports. The anticipated duration of 2000 m AR competitions is either comparable or considerably lower than that of the other Paralympic disciplines with similar characteristics. AR has inherent injury and health risks especially within thorax, shoulders and low back region, but they are not expected to be significantly modified by increased racing times. Specific considerations need to be taken into account for athletes with a spinal cord injury, like in other sport disciplines. There are no distinctive contra-indications for AR events of 2000 m based on the current literature review and a 10-year experience in this sport. Long-term follow-ups are needed to understand fully the injury and health risk associated with AR and to develop appropriate prevention strategies.

Intensity control in swim training by means of the individual anaerobic threshold

This study aimed at evaluating the homogeneity of physiological responses during swim training bouts with intensities prescribed by reference to the individual anaerobic threshold (IAT). Eighteen competitive front crawl swimmers (female 5, male 13, 10 long-distance, and 8 short-distance swimmers [LDSs, SDSs], age: 17 ± 1.7 years, training history: 7.0 ± 2.8 years, training volume per week: 35 ± 5.7 km) performed an incremental swimming test to determine the IAT. Within a maximum of 3 weeks, 4 training programs were conducted: 20 × 100-m low-intensity endurance training (EN(low), 97% IAT), 5 × 400-m high-intensity endurance training (EN(high), 101% IAT), 5 × 200 m (IT1, 105% IAT), and 10 × 100 m (IT2, 108% IAT) intensive interval training. Blood lactate concentrations (bLa) were determined during each training session. The results are given as median (25th and 75th percentiles). During EN(low) and EN(high), the mean bLas were 1.8 mmol·L(-1) (1.3/3.0 mmol·L(-1)) and 4.4 mmol·L(-1) (3.9/6.4 mmol·L(-1)). The bLas were higher during both IT programs: IT1, 6.3 mmol·L(-1) (5.6/7.2 mmol·L(-1)); IT2, 5.8 mmol·L(-1) (5.0/6.5 mmol·L(-1)). The bLas of most individuals were close to the median values (±2.4 mmol·L(-1)). However, in each of the training programs, some subjects showed bLa values that were clearly above (3-7 mmol·L(-1) higher). In particular, SDSs reached higher bLas at the same intensity compared with LDSs. It is concluded that intensity prescriptions by means of IAT seem to elicit an expected metabolic response in approximately 85% of swim training sessions. The observed average bLa is in the range of those recommended in the scientific literature.

Prevention, diagnosis, and treatment of the overtraining syndrome: joint consensus statement of the European College of Sport Science and the American College of Sports Medicine

Successful training not only must involve overload but also must avoid the combination of excessive overload plus inadequate recovery. Athletes can experience short-term performance decrement without severe psychological or lasting other negative symptoms. This functional overreaching will eventually lead to an improvement in performance after recovery. When athletes do not sufficiently respect the balance between training and recovery, nonfunctional overreaching (NFOR) can occur. The distinction between NFOR and overtraining syndrome (OTS) is very difficult and will depend on the clinical outcome and exclusion diagnosis. The athlete will often show the same clinical, hormonal, and other signs and symptoms. A keyword in the recognition of OTS might be "prolonged maladaptation" not only of the athlete but also of several biological, neurochemical, and hormonal regulation mechanisms. It is generally thought that symptoms of OTS, such as fatigue, performance decline, and mood disturbances, are more severe than those of NFOR. However, there is no scientific evidence to either confirm or refute this suggestion. One approach to understanding the etiology of OTS involves the exclusion of organic diseases or infections and factors such as dietary caloric restriction (negative energy balance) and insufficient carbohydrate and/or protein intake, iron deficiency, magnesium deficiency, allergies, and others together with identification of initiating events or triggers. In this article, we provide the recent status of possible markers for the detection of OTS. Currently, several markers (hormones, performance tests, psychological tests, and biochemical and immune markers) are used, but none of them meet all the criteria to make their use generally accepted.