Impact of stretching on the performance and injury risk of long-distance runners

Do Exercise-Based Prevention Programs Reduce Injury in Endurance Runners? A Systematic Review and Meta-Analysis

BACKGROUND

Endurance running is a popular sport and recreational activity yet is associated with a high prevalence of injury. Running related injuries (RRIs) are a leading cause of drop-out and represent a substantial financial burden to runners and healthcare services. There is clear evidence for the use of exercise-based injury prevention programs in games-based and youth sport settings, yet the research investigating the use of exercise to reduce injury risk in endurance runners has not been adequately reviewed recently.

OBJECTIVES

The aim of this review and meta-analysis was to systematically summarize the current research that has investigated the effect of exercise-based prevention programs and their state of supervision on the risk of RRIs in endurance runners.

METHODS

Three databases were searched for relevant studies. Selection and review were completed by two independent reviewers using the following inclusion criteria: (1) study population used endurance running training for health, occupational, or performance outcome(s); (2) participants performed running as their main form of exercise (> 50% of their total training time); (3) study was a randomized controlled trial; (4) a non-running-based exercise intervention was used; (5) a running-only or placebo exercise control group was included; (6) injury rate or incidence was reported; (7) injuries were recorded prospectively alongside the exercise training. Two meta-analyses were conducted using random-effects models, one based on log risk ratio and one based on log incidence rate ratio. The Cochrane Risk of Bias Assessment Tool 2 was used to evaluate the quality of studies and the Grading of Recommendations Assessment, Development and Evaluations approach was employed to grade the certainty of evidence.

RESULTS

A total of nine articles containing 1904 participants were included in analysis. Overall pooled results showed no significant differences between intervention and control groups in injury risk (z = - 1.60; p = 0.110) and injury rate (z = - 0.98; p = 0.329), while a post hoc analysis evaluating supervised interventions only showed that injury risk was significantly lower in the intervention group compared to the control group (z = - 3.75, p < 0.001). Risk of bias assessment revealed that seven studies included in the analysis were of low quality.

CONCLUSIONS

Exercise-based interventions do not appear to reduce the risk and rate of running-related injuries. Supervision may be essential for exercise-based intervention programs to reduce risk of RRIs, possibly due to increased compliance. Studies with more robust designs that include supervised exercise interventions should be prioritized in the future.

TRIAL REGISTRY

Clinical Trial Registration: PROSPERO CRD42021211274.

Relationship between muscular extensibility, strength and stability and the transmission of impacts during fatigued running

The aim was to analyse the relationship between isokinetic strength, dynamic stability, muscular extensibility and impacts transmission during fatigued running. Low- and high-frequency impacts-related to body movements and the severity of impacts, respectively-were assessed in 17 male recreational runners, before and after a treadmill running fatigue protocol, using a triaxial accelerometry system. High-frequency impacts in the tibia were negatively correlated to the knee angle at which the quadriceps peak torque was reached (p = 0.014), and also to the extensibility of the hamstrings and soleus (p = 0.001 and p = 0.023, respectively). The increases of high-frequency impacts in tibia caused by fatigue were positively related to the knee angle at which the hamstrings peak torque was reached (p = 0.001) and to stability after landing (p = 0.007). The attenuation of high-frequency impacts was positively related to hamstrings/quadriceps ratio of strength (p = 0.010) and to stability (p = 0.006). Limiting possible deficits in hamstring and soleus range of motion, improving stability after landing, developing hamstring and quadriceps strength in elongated muscle range, and maintaining a balanced ratio of hamstring/quadriceps strength could help to reduce the injury risk in running.

Aerobic, muscle-strengthening, and flexibility physical activity and risks of all-cause and cause-specific mortality: a population-based prospective cohort of Korean adults

BACKGROUND

Studies have shown that aerobic and muscle-strengthening physical activities reduce mortality risk. However, little is known about the joint associations of the two activity types and whether other type of physical activity, such as flexibility activity, can provide similar mortality risk reduction.

OBJECTIVES

We examined the independent associations of aerobic, muscle-strengthening, and flexibility physical activities with all-cause and cause-specific mortality in a population-based prospective cohort of Korean men and women. We also examined the joint associations of aerobic and muscle-strengthening activities, the two physical activity types that are recommended by the current World Health Organization physical activity guidelines.

DESIGN

This analysis included 34,379 Korea National Health and Nutrition Examination Survey 2007-2013 participants (aged 20-79 years) with mortality data linkage through December 31, 2019. Engagement in walking, aerobic, muscle-strengthening, and flexibility physical activities was self-reported at baseline. Cox proportional hazards model was performed to estimate hazard ratios (HRs) and 95% confidence intervals (CIs), adjusting for potential confounders.

RESULTS

Flexibility physical activity (≥ 5 vs. 0 d/wk) was inversely associated with all-cause (HR [95% CI] = 0.80 [0.70-0.92]; P-trend < 0.001) and cardiovascular mortality (0.75 [0.55-1.03], P-trend = 0.02). Moderate- to vigorous-intensity aerobic physical activity (≥ 50.0 vs. 0 MET-h/wk) was also associated with lower all-cause (HR [95% CI] = 0.82 [0.70-0.95]; P-trend < 0.001) and cardiovascular mortality (0.55 [0.37-0.80]; P-trend < 0.001). Similar inverse associations were observed with total aerobic physical activity, including walking. Muscle-strengthening activity (≥ 5 vs. 0 d/wk) was inversely associated with all-cause mortality (HR [95% CI] = 0.83 [0.68-1.02]; P-trend = 0.01) but was not associated with cancer or cardiovascular mortality. Compared to participants meeting the highest guidelines for both moderate- to vigorous-intensity aerobic and muscle-strengthening physical activities, those not meeting in any guideline were associated with higher all-cause (1.34 [1.09-1.64]) and cardiovascular mortality (1.68 [1.00-2.82]).

CONCLUSIONS

Our data suggest that aerobic, muscle-strengthening, and flexibility activities are associated with lower risk of mortality.

Stretching and Releasing of Iliotibial Band Complex in Patients with Iliotibial Band Syndrome: A Narrative Review

Iliotibial band syndrome (ITBS) is one of the most common overuse syndromes causing knee pain; it is especially prevalent in runners and also common in cyclists, rowers, and field athletes, with occasional cases occurring in non-athletes too. ITBS symptoms can negatively affect not only knee function, but also mental and physical aspects of health-related quality of life. Although various conservative treatment options have been investigated and discussed, there is still no consensus on a standard of care for ITBS. Moreover, the literature on the etiology and risk factors of ITBS, which could help in selecting appropriate treatment methods, is conflicting and inconclusive. The role of individual treatment modalities such as stretching and releasing techniques has not been extensively studied and remains unclear. In this article, we will critically review the available evidence for the benefits of ITB stretching and "release" methods in the treatment of ITBS. In addition to the direct evidence (clinical studies examining the effects of ITB stretching and other methods that purportedly stretch or "release" the ITB), we present several additional lines of reasoning that discuss the rationale for ITB stretching/releasing in terms of the etiology of ITBS, the mechanical properties and behavior of the ITB, and the risk factors for ITBS development. We conclude that the current literature provides some evidence for the inclusion of stretching or other "release" methods in the early rehabilitation of ITBS. Long-term interventions typically include ITB stretching; however, it remains unclear to what extent stretching within a multimodal treatment actually contributes to resolving the symptoms. At the same time, there is no direct evidence to suggest that stretching and "release" methods have any negative effects.

Healthcare providers have insufficient up-to-date knowledge of lower limb sports injuries, and their knowledge is similar to that of athletes

BACKGROUND

Being up-to-date with evidence-based knowledge of lower limb sports injuries is essential for Healthcare professionals (HCPs).

PURPOSE

To assess whether HCPs possess up-to-date knowledge of lower limb sports injuries by comparing their knowledge to that of athletes.

METHODS

With an expert panel, we developed an online quiz of 10 multiple-choice questions on various topics related to lower-limb sports injuries. Maximal score was 100. We used social media to invite HCPs (5 groups: Physiotherapists, Chiropractors, Medical Doctors, Trainers, and Other therapists) and athletes of all levels (amateur, semi-pro, and pro) to participate. We drafted the questions according to conclusions from the latest systematic reviews and meta-analyses.

RESULTS

1526 participants completed the study. Final quiz scores ranged from zero (n = 28, 1.8%) to 100 (n = 2, 0.1%) and were distributed normally with a mean score of 45.4 ± 20.6. None of the 6 groups' means surpassed the set threshold of 60 points. Multiple linear regressions of covariates indicated that age, gender, engagement in physical activity, learning hours per week, reading scientific journals, reading popular magazines and blogs, trainers, and other therapists' groups explained 19% of the variances (-5.914<β < 15.082, 0.000<p < 0.038).

CONCLUSIONS

HCPs have insufficient up-to-date knowledge of lower limb sports injuries, and their knowledge is similar to that of athletes of all levels. HCPs probably do not possess the proper tools to assess scientific literature Academic and sports medicine societies should look into ways to improve the scientific knowledge integration of HCPs.

Resistance Exercise for Improving Running Economy and Running Biomechanics and Decreasing Running-Related Injury Risk: A Narrative Review

It is well-accepted that at least a certain amount of resistance exercise (RE) is recommended for most endurance athletes. In this review, we aim to summarize the evidence regarding the effects of RE on running economy, running biomechanics, and running-related injury risk in endurance runners. The evidence robustly shows that lower limb RE is effective for improving running economy and performance, with a combination of strength and plyometric training being recommended to improve RE. Isometric training is also emerging as a possible alternative to implement during periods of high overall training load. Lower limb RE may change some aspects of joint kinematics during running; however, the evidence regarding the effects on kinetics is limited. Lower limb RE may help reduce running-related injury risk, but further evidence is needed.

The Effect of Static and Dynamic Stretching during Warm-Up on Running Economy and Perception of Effort in Recreational Endurance Runners

This randomized crossover counterbalanced study investigated, in recreational runners, the acute effects of pre-exercise stretching on physiological and metabolic responses, endurance performance, and perception of effort. Eight male endurance runners (age 36 ± 11 years) performed three running-until-exhaustion tests, preceded by three warm-ups, including the following different stretching protocols: static (SS), dynamic (DS), and no-stretching (NS). During the SS and DS sessions, the warm-up consisted of 10 min of running plus 5 min of SS or DS, respectively, while during the NS session, the warm-up consisted of 15 min of running. Physiological and metabolic responses, and endurance running performance parameters, were evaluated. The perception of effort was derived from the rating of perceived exertion (RPE). Running economy significantly improved after SS (p < 0.05) and DS (p < 0.01), and RPE values were significantly lower in SS (p < 0.05) and DS (p < 0.01), compared to NS. No differences in physiological and metabolic responses among the sessions were found. This study showed that including SS and DS within the warm-up ameliorated running economy and decreased the perception of effort during a running-until-exhaustion test, highlighting the benefits of stretching on endurance performance. These results should encourage recreational runners to insert stretching during warm-up, to optimize the running energy costs, reducing the perception of effort and making the training sessions more enjoyable.

Auto-Regulation Method vs. Fixed-Loading Method in Maximum Strength Training for Athletes: A Systematic Review and Meta-Analysis

The auto-regulation method is a rising training strategy to improve strength and motor performance, and the Autoregulatory Progressive Resistance Exercise (APRE), Rating of Perceived Exertion program (RPE), and Velocity-Based Training (VBT) are the three common auto-regulation programs. However, whether the auto-regulation method is more effective than the traditional strength training (the fixed-loading method) in maximum strength training is still unclear. The present study searched the Pubmed, SPORTDiscus, Web of Science, Embase, EBSCO, Cochrane, CNKI, and CQVIP databases, and included eight related studies published between 2010 and 2020, with a total of 166 subjects including division 1 college players and athletes with at least 1-year training history, and interventions ranging from 5 to 10 weeks. A meta-analysis was performed to check the difference between the two training methods, and analyzed the differences in the existing auto-regulation programs' effectiveness. The overall results showed that the auto-regulation method was more effective than the fixed-loading method in maximum strength training (effect size = 0.64; P < 0.001; I² = 0%). In specific, the pooled results in subgroup analysis indicated that the auto-regulation method may effectively improve the strength performance in squat (effect size = 4.64; P < 0.05; I² = 54%) and bench press (effect size = 3.21; P < 0.05; I² = 62%). Greater benefits of the auto-regulation method on strength improvement could be achieved in an 8-week or even shorter training (effect size = 0.87; P < 0.001; I² = 0%) compared with those of 8–10 weeks (effect size = 0.32; P < 0.001; I² = 0%). The APRE is the most effective training program among the three auto-regulation programs (effect size = 0.78; P < 0.001; I² = 0%). In conclusion, the auto-regulation method could be more effective than the fixed-loading method in maximum strength training. The APRE is a convenient and effective training program that may be considered a practical training program to replace traditional training in athletes.

Effect of hamstring tissue flossing during warm-up on sit and reach performance

BACKGROUND

Tissue flossing, also called voodoo flossing, is becoming a popular adjunct to athletic training to improve joint range of motion and muscle strength. The authors of this technique believe that tissue flossing can be used during warm-up. This study investigated the effect of tissue flossing during warm-up on the range of motion in the sit and reach test.

METHODS

The study enrolled 40 recreational athletes divided into an experimental and control group consisting of 20 participants each. The range of trunk flexion was assessed with the sit and reach test. Participants were tested before as well as immediately and 15, 30 and 45 minutes after completing the 9-minute warm-up. During the warm-up, athletes in the experimental group wore a floss band on the thigh muscles, while athletes in the control group exercised without wearing a floss band.

RESULTS

The sit and reach test revealed an improved range of motion after the warm-up in both groups (p<0.05). The improvement was noted at all time points. Regression analysis showed no effect of any of the study parameters (group assignment, sex, age, body mass index, pain intensity on a visual analogue scale) on the improvement in the sit and reach test results.

CONCLUSIONS

The similar results obtained in both groups indicate that there may not be a rationale for using tissue flossing during warm-up to improve trunk and hip flexibility.

Strength and Conditioning Habits of Competitive Distance Runners

Blagrove, RC, Brown, N, Howatson, G, and Hayes, PR. Strength and conditioning habits of competitive distance runners. J Strength Cond Res 34(5): 1392-1399, 2020-Targeted strength and conditioning (S&C) programs can potentially improve performance and reduce injury risk factors in competitive runners. However, S&C practices of distance runners are unknown. This study aimed to explore S&C practices of competitive middle- and long-distance runners and examined whether reported frequency of injuries was influenced by training behaviors. One thousand eight hundred eighty-three distance runners (≥15 years old) completed an online survey. All runners who raced competitively were included in data analysis (n = 667). Distance runners mainly engaged with S&C activities to lower risk of injury (63.1%) and improve performance (53.8%). The most common activities used were stretching (86.2%) and core stability exercises (70.2%). Resistance training (RT) and plyometric training (PT) were used by 62.5 and 35.1% of runners, respectively. Junior (under-20) runners include PT, running drills, and circuit training more so than masters runners. Significantly more international standard runners engaged in RT, PT, and fundamental movement skills training compared with competitive club runners. Middle-distance (800-3,000 m) specialists were more likely to include RT, PT, running drills, circuit training, and barefoot exercises in their program than longer-distance runners. Injury frequency was associated with typical weekly running volume and run frequency. Strength and conditioning did not seem to confer a protection against the number of injuries the runners experienced. Practitioners working with distance runners should critically evaluate the current S&C practices of their athletes, to ensure that activities prescribed have a sound evidence-based rationale.

Running coaches and running group leaders' engagement with, and beliefs and perceived barriers to prehabilitation and injury prevention strategies for runners

OBJECTIVES

To identify which pre-and post-run injury risk reduction activities and prehabilitation (prehab) strategies Coaches and Running Group Leaders (Coaches/RGLs) engage in with runners; to explore their beliefs on why runners get injured; to identify Coaches/RGLs confidence providing injury prevention activities, and what they believe are effective for reducing risk of injury; to identify their perceived barriers to including prehab during running coaching/training.

DESIGN

Survey; Participants: UK Coaches/RGLs (N = 100) OUTCOME MEASURES: Online questionnaire with open, closed and Likert scale questions.

RESULTS

Most Coaches/RGLs performed active warm-ups (97%), cool-downs (94%),gave injury prevention advice (91%), and advice on recovery strategies (84%) during training. Fewer coaches/RGLs incorporated prehab (67%). Although they collectively exhibited a wide range of knowledge, individually there was less consistency and confidence providing this. Prehab was rated as very important for injury risk reduction, with supervision recommended to facilitate runner engagement. Coaches/RGLs found conflicting advice, time, environment, and resistance from runners as barriers to incorporating prehab into training.

CONCLUSION

Coaches/RGLs believe prehab is important for runners however lack of confidence and knowledge appeared to limit the wider inclusion of prehab with runners. Coaches/RGLs welcomed reputable information on prehab from evidence-based sources. This may assist in reducing injury.

Factors Affecting Training and Physical Performance in Recreational Endurance Runners

Endurance running has become an immensely popular sporting activity, with millions of recreational runners around the world. Despite the great popularity of endurance running as a recreational activity during leisure time, there is no consensus on the best practice for recreational runners to effectively train to reach their individual objectives and improve physical performance in a healthy manner. Moreover, there are lots of anecdotal data without scientific support, while most scientific evidence on endurance running was developed from studies observing both recreational and professional athletes of different levels. Further, the transference of all this information to only recreational runners is difficult due to differences in the genetic predisposition for endurance running, the time available for training, and physical, psychological, and physiological characteristics. Therefore, the aim of this review is to present a selection of scientific evidence regarding endurance running to provide training guidelines to be used by recreational runners and their coaches. The review will focus on some key aspects of the training process, such as periodization, training methods and monitoring, performance prediction, running technique, and prevention and management of injuries associated with endurance running.

Influence of the ACTN3 R577X genotype on the injury epidemiology of marathon runners

A common single nucleotide polymorphism in the ACTN3 gene might result in the complete deficiency of α-actinin-3 (i.e., XX genotype). It has been found that ACTN3 XX individuals have several traits related to lessened muscle performance. This study aimed to determine the influence, if any, of ACTN3 genotypes on injury incidence of marathoners during the year preceding to participating in a competitive marathon race. Using a cross-sectional experimental design, the type and conditions of sports injuries were documented for one year in a group of 139 marathoners. Injuries were recorded following a consensus statement on injuries in Athletics. Afterward, ACTN3 genotyping was performed, and injury epidemiology was compared among RR, RX, and XX genotypes. The distribution of the RR/RX/XX genotypes was 28.8/42.8/23.5%, respectively. A total of 67 injuries were recorded. The frequency of marathoners that reported any injury during the previous year was not different across the genotypes (55.0/38.8/40.6%, P = 0.241). Although the overall injury incidence was not different among genotypes (2.78/1.65/1.94 injuries/1000 h of running, P = 0.084), the likelihood of suffering an injury was higher in RR than in RX (OR = 1.93: 95%CI = 0.87–4.30), and higher than in XX (OR = 1.79: 0.70–4.58). There was no difference in the conditions, severity, body location, time of year, or leading cause of injury among genotypes. However, XX presented a higher frequency of sudden-onset injuries (P = 0.024), and the OR for muscle-type injuries was 2.0 (0.51–7.79) times higher compared to RR runners. Although XX marathoners did not have a higher overall incidence of injury, the OR in these runners for muscle-type injuries was superior to RR and RX runners. The likelihood of suffering a muscle injury, especially with a sudden-onset, was twice in XX than in RR endurance runners.

In training for a marathon: Runners and running-related injury prevention

OBJECTIVE

To investigate which preventive measures runners use when preparing for a half- or full-marathon and whether the use of these measures at baseline and during the preparation-period differs between runners who sustained no/non-substantial running-related injuries (NSIRs) or substantial running-related injuries (SIRs).

DESIGN

Prospective cohort study.

SETTING

16-week period before the Utrecht Marathon.

PARTICIPANTS

Runners who subscribed for the half- or full-marathon.

MAIN OUTCOME MEASURES

The occurrence of RRIs was registered every 2-weeks, using the Dutch version of the Oslo Sport Trauma Research Center (OSTRC) questionnaire on Health Problems. The OSTRC was used to differentiate between runners with SIRs (question 2/3 score>12) and NSIRs (question 2/3 score<13). The use of different preventive measures, was registered every 4-weeks.

RESULTS

51.6% of the runners reported at least one RRI in the 12-months prior to this study (history of RRIs). The SIRs with a history of RRIs more often asked for running shoe advice than NSIRs with a history of RRIs (67.9%vs43.4%, P < 0.05); 18.9% of the SIRs with a history of RRIs used supportive materials for knee and/or ankle versus 0% of NSIRs with a history of RRIs (P < 0.05).

CONCLUSION

SIRs with a history of RRIs might be using their preventive measures for symptom reduction or secondary prevention.

Sport injury prevention in-school and out-of-school? A qualitative investigation of the trans-contextual model

OBJECTIVE

To investigate junior secondary school students' experiences and perspectives of in-school and out-of-school sport-safety, with a particular focus on the meaning and content that they applied to the motivational and social cognitive factors of sport injury prevention.

DESIGN

Focus-group interview.

METHOD

Participants were 128 junior secondary school students (Form 1 to Form 3) aged between 12 and 16 years from two secondary schools. We organised focus-group interviews by class (group size = six to nine students). Seventeen groups completed semi-structured interviews regarding their experience, beliefs, and motives for injury prevention in-school and out-of-school. We analysed data by thematic content analysis using a typological approach.

RESULTS

Higher order themes (N = 7) including in-school and out-of-school motives and social cognitive factors and associated lower-order themes (N = 16), emerged from the analysis corresponding to constructs from trans-contextual model tenets.

CONCLUSIONS

The current study is the first qualitative study to explore junior secondary school students' experience and perspectives on sport injury prevention, using trans-contextual model as a framework for investigation. The findings contribute to a better understanding on their motivational and social cognitive factors in adopting sport injury prevention. The content of the theme behavior also indicated the inadequacy of students' knowledge of effective sport injury prevention techniques, and underscored the importance of sport safety education.

Short-Term Effects of Rolling Massage on Energy Cost of Running and Power of the Lower Limbs

PURPOSE

Self-myofascial release (SMFR) is a type of self-massage that is becoming popular among athletes. However, SMFR's effects on running performance have not yet been investigated. The aim of this study was to evaluate the effects of SMFR on the cost of running (Cr). In addition, the authors evaluated the effects of SMFR on lower-limb muscle power.

METHODS

Cr and lower-limb muscle power during squat jump (SJ) and countermovement jump (CMJ) were measured before (PRE), immediately after (POST), and 3 h after (POST 3h) an SMFR protocol (experimental condition). In the control-condition testing session, the same measurements were performed without undergoing the SMFR protocol. Experimental and control conditions were tested in a randomized order.

RESULTS

Cr at POST trended to increase compared with PRE (+6.2% [8.3%], P = .052), whereas at POST 3h, Cr was restored to PRE values (+0.28% [9.5%], P = .950). In the experimental condition, no significant effect of time was observed for maximal power exerted during SJ. By contrast, maximal power exerted during CMJ at POST and at POST 3h was significantly higher than that observed at PRE (+7.9% [6.3%], P = .002 and +10.0% [8.7%], P = .004, respectively). The rate of force development measured during CMJ also increased after SMFR, reaching statistical significance at 200 ms from force onset at POST 3h (+38.9%, P = .024).

CONCLUSIONS

An acute use of foam rollers for SMFR performed immediately prior to running may negatively affect endurance running performance, but its use should be added before explosive motor performances that include stretch-shortening cycles.

Effects of Foam Rolling on Range of Motion, Peak Torque, Muscle Activation, and the Hamstrings-to-Quadriceps Strength Ratios

Madoni, SN, Costa, PB, Coburn, JW, and Galpin, AJ. Effects of foam rolling on range of motion, peak torque, muscle activation, and the hamstrings-to-quadriceps strength ratios. J Strength Cond Res 32(7): 1821-1830, 2018-To examine the effects of foam rolling (FR) on range of motion (ROM), peak torque (PT), hamstrings-to-quadriceps (H:Q) ratios, and muscle activation. Twenty-two recreationally active women (mean age ± SD = 21.55 ± 1.82 years, 161.91 ± 6.58 cm, 61.47 ± 10.54 kg) volunteered for this study. Participants performed pre- and posttests analyzing PT and surface electromyography (EMG) of their dominant limb, completing maximal knee extension and flexion at 3 different velocities. Participants foam rolled the hamstrings muscles or sat for the control condition between the pre- and posttests. Hamstrings ROM increased in the FR condition from (mean ± SE) 123.23 ± 3.49 to 126.41 ± 3.62° (p < 0.001) and decreased in the control condition from 118.82 ± 4.25 to 117.95 ± 4.29° (p = 0.013). Concentric hamstrings PT and conventional H:Q ratios decreased after both conditions, with smaller decreases after FR (p ≤ 0.05). No significant changes were found for eccentric hamstrings PT, eccentric hamstrings EMG, or functional H:Q ratios (p > 0.05). Foam rolling resulted in greater changes in hamstrings ROM without creating a deficit in PT or muscle activation when compared with the control group. When compared with other methods of stretching, FR may be beneficial in increasing ROM without decreasing functional H:Q ratios.

Prevalência de lesão e fatores associados em corredores de rua da cidade de Juiz de Fora (MG)

RESUMO No Brasil, a corrida de rua é o segundo esporte mais praticado; entretanto, pode ocasionar lesões musculoesqueléticas. Estudos sobre o tema são importantes para nortear estratégias de prevenção e intervenção. Assim, o objetivo foi investigar a prevalência de lesões e os fatores associados em corredores de rua da cidade de Juiz de Fora(MG). Trata-se de um estudo observacional do tipo transversal. A amostra foi selecionada por conveniência. Foram incluídos corredores amadores, entre 18 e 60 anos e que realizavam treinos em diferentes locais da cidade. Foram excluídos participantes com histórico de fratura e osteossíntese em membros inferiores ou que praticassem outro esporte que não fosse a musculação. Para analisar os dados, foram utilizados os testes t de Student, Mann-Whitney e X2 (α=0,05). Os participantes foram alocados em grupo lesão (GL, n=37) e grupo sem lesão (GSL, n=113). A prevalência de lesão foi de 24,7%. O GL praticava a corrida há mais tempo (76,2 ± 9,1 × 36,7 ± 39,0 meses; P<.01), teve menor aumento da frequência semanal do treinamento (49,5% × 54,2%; P=.04), realizou menos alongamento prévio (48,6% × 75,2%; P=.02), apresentou maior percentual de análise da marcha para escolha do calçado (62,1% × 43,3%; P=.04) e uso de palmilha (35,1% X 14,1%; P=<.01). A prevalência de lesões foi baixa. Os que correm há mais tempo têm maior risco de lesão mesmo sem incremento na frequência semanal. O alongamento foi protetor e a prescrição de calçado e palmilha indiscriminados não garantiram resultados satisfatórios.

Validity of injury self-reports by novice runners: comparison with reports by sports medicine physicians

This study examined the criterion validity of self-reported running-related injuries (RRI) by novice runners. Fifty-eight participants (41 females; age 46 ± 11 yrs) of the "Start-to-Run" program provided self-reports on their RRIs using an online questionnaire. Subsequently, they attended injury consultations with sports medicine physicians who provided physician-reports (blinded for the self-reports) as a reference standard. Self-reports and physician-reports included information on injury location (i.e., hip/groin, upper leg, knee, lower leg, and ankle/foot) and injury type (i.e., muscle-tendon unit, joint, ligament, or bone). Sensitivity, specificity, and positive predictive values were 100% for all five injury locations. For injury type, sensitivity was low (66% for muscle-tendon unit, 50% for ligament, and 40% for bone) and lowest for joint injuries (17%). In conclusion, the validity of self-reported RRIs by novice runners is good for injury locations but not for injury types. In particular for joint injuries, the validity of novice runners' self-reports is low. Abbreviations: RRI: Running Related Injury; SMC: Sports Medicine Centre; MTU: Muscle Tendon Unit; PPV: Positive Predictive Value.

Do We Need a Cool-Down After Exercise? A Narrative Review of the Psychophysiological Effects and the Effects on Performance, Injuries and the Long-Term Adaptive Response

It is widely believed that an active cool-down is more effective for promoting post-exercise recovery than a passive cool-down involving no activity. However, research on this topic has never been synthesized and it therefore remains largely unknown whether this belief is correct. This review compares the effects of various types of active cool-downs with passive cool-downs on sports performance, injuries, long-term adaptive responses, and psychophysiological markers of post-exercise recovery. An active cool-down is largely ineffective with respect to enhancing same-day and next-day(s) sports performance, but some beneficial effects on next-day(s) performance have been reported. Active cool-downs do not appear to prevent injuries, and preliminary evidence suggests that performing an active cool-down on a regular basis does not attenuate the long-term adaptive response. Active cool-downs accelerate recovery of lactate in blood, but not necessarily in muscle tissue. Performing active cool-downs may partially prevent immune system depression and promote faster recovery of the cardiovascular and respiratory systems. However, it is unknown whether this reduces the likelihood of post-exercise illnesses, syncope, and cardiovascular complications. Most evidence indicates that active cool-downs do not significantly reduce muscle soreness, or improve the recovery of indirect markers of muscle damage, neuromuscular contractile properties, musculotendinous stiffness, range of motion, systemic hormonal concentrations, or measures of psychological recovery. It can also interfere with muscle glycogen resynthesis. In summary, based on the empirical evidence currently available, active cool-downs are largely ineffective for improving most psychophysiological markers of post-exercise recovery, but may nevertheless offer some benefits compared with a passive cool-down.

Sports and environmental temperature: From warming-up to heating-up

Most professional and recreational athletes perform pre-conditioning exercises, often collectively termed a 'warm-up' to prepare for a competitive task. The main objective of warming-up is to induce both temperature and non-temperature related responses to optimize performance. These responses include increasing muscle temperature, initiating metabolic and circulatory adjustments, and preparing psychologically for the upcoming task. However, warming-up in hot and/or humid ambient conditions increases thermal and circulatory strain. As a result, this may precipitate neuromuscular and cardiovascular impairments limiting endurance capacity. Preparations for competing in the heat should include an acclimatization regimen. Athletes should also consider cooling interventions to curtail heat gain during the warm-up and minimize dehydration. Indeed, although it forms an important part of the pre-competition preparation in all environmental conditions, the rise in whole-body temperature should be limited in hot environments. This review provides recommendations on how to build an effective warm-up following a 3 stage RAMP model (Raise, Activate and Mobilize, Potentiate), including general and context specific exercises, along with dynamic flexibility work. In addition, this review provides suggestion to manipulate the warm-up to suit the demands of competition in hot environments, along with other strategies to avoid heating-up.