A systematic review of running-related musculoskeletal injuries in runners

Co-creation of injury prevention measures for competitive adolescent distance runners: knowledge, behavior, and needs of athletes and coaches enrolled on England Athletics' Youth Talent Programme

This study assessed the knowledge, behavior, and needs of competitive adolescent (16-18 years) distance runners and distance running coaches enrolled as part of England Athletics' Youth Talent Programme in relation to the prevention of running-related injury (RRI). Two online surveys were developed and distributed to the distance runners (survey one) and coaches (survey two). Both surveys included sections related to: (1) current knowledge; (2) current behavior; (3) need and support for RRI prevention measures; and (4) possible content and form of RRI prevention measures. A total of 39 distance runners (36% of total possible sample) completed survey 1, and 29 coaches (32% of total possible sample) completed survey 2. Key findings included that the majority of distance runners and coaches: (1) agreed that it is 'very important' to try to prevent RRI; (2) are currently implementing something in practice (e.g., strength training) to prevent RRI; and (3) view the creation of RRI prevention measures as an important initiative. Differences between distance runners and coaches were identified in relation to their understanding of the most common causes of RRI. Interestingly, distance runners identified a modifiable cause of RRI (i.e., too much training) as the most common cause of RRI, while coaches selected a non-modifiable cause of RRI (i.e., growth and maturation). These key findings were supplemented by competitive adolescent runners and distance running coaches detailing their delivery preferences for such RRI prevention measures. Results from this study will help inform subsequent steps of the larger co-creation process, with an emphasis on developing multifaceted and context-specific RRI prevention measures that are deemed to be feasible and acceptable for real-world implementation.

Risk factors for running-related injuries: An umbrella systematic review

PURPOSE

This umbrella systematic review (SR) of SRs and meta-analysis seeks to comprehensively synthesize existing literature to identify and consolidate the diverse range of risk factors contributing to running-related injuries (RRIs).

METHODS

Systematic searches were conducted on June 28, 2023, across Web of Science, SPORTDiscus, Scopus, PubMed, and Cochrane Library. We included SRs, whether accompanied by meta-analyses or not, that focused on investigating risk factors for RRIs within observational studies. The methodological quality of the SRs was evaluated using the Assessing the Methodological Quality of Systematic Reviews II. To assess the extent of overlap across reviews, the corrected covered area metric was calculated.

RESULTS

From 1509 records retrieved, 13 SRs were included. The degree of overlap between SRs was low (4%), and quality varied from critically low (n = 8) to low (n = 5). Two hundred seven outcomes assessed in 148 primary studies were identified as being associated with the occurrence of RRIs. The effect sizes of the associations for which risk measures were reported (n = 131) were classified as large (n = 30, 23%), medium (n = 38, 29%), small (n = 48, 37%) or no effect (n = 15, 11%). Running/training characteristics, health and lifestyle factors, along with morphological and biomechanical aspects, exhibit large effect sizes in increasing the risk for RRIs.

CONCLUSION

Drawing from the outcomes of the low-quality SRs and associations with large effect sizes, our findings indicate that running/training characteristics and health and lifestyle factors, as well as morphological and biomechanical aspects, are all implicated in elevating the risk of RRIs, emphasizing the multifactorial basis of injury incidence in running. Given the low quality and heterogeneity of SR, individual findings warrant cautious interpretation.

The effect of knee braces on knee joint kinematics at different exercise speeds

This study aims to investigate the influence of a new semi-rigid knee joint braces on kinematics using the Opti-knee knee joint kinematic analysis system at various exercise speeds. Twenty-four healthy young male adults were recruited for this study. Participants were randomly assessed while wearing and not wearing knee brace at four different speeds on a treadmill: normal walking (3.6 km/h), brisk walking (5.4 km/h), jogging (9 km/h), and moderate intensity running (10.8 km/h). Six degrees of freedom kinematic data from the knee joint were collected. Paired t-tests were conducted to calculate the kinematic differences. At speeds of 3.6 km/h and 5.4 km/h, wearing the knee brace led to reduced knee joint mobility in anterior-posterior translation, superior-inferior translation, internal-external rotation, and flexion-extension angles during the stance phase (P < 0.05). At 9 km/h, wearing the brace reduced knee joint internal-external rotation and flexion-extension mobility during the stance phase (P < 0.05). At 10.8 km/h, wearing the brace reduced knee joint flexion-extension mobility during the stance phase (P < 0.05). Wearing brace has significant influence on knee kinematics at four speeds, and the effect of brace varies with the speed of movement.

Can Foot Orthoses Benefit Symptomatic Runners? Mechanistic and Clinical Insights Through a Scoping Review

BACKGROUND

Running is a widely practiced sport worldwide associated with a host of benefits on cardiovascular, metabolic, musculoskeletal, and mental health, but often leads to musculoskeletal overuse injuries. The prescription of a foot orthosis (FO) is common to manage musculoskeletal impairments during physical activity or functional tasks. Although FOs are frequently prescribed by clinicians for symptomatic populations of runners, the existing literature supporting the prescription of FOs in runners has predominantly focused on either uninjured individuals or a mix of uninjured and symptomatic populations. Thus, the effects of FOs on the treatment and/or prevention of overuse running injuries need to be investigated to guide future research and assist clinicians in their decision-making process.

MAIN BODY

This scoping review aimed to evaluate the immediate and long-term effects of FOs on lower limb biomechanics, neuromuscular parameters, and pain and disability in symptomatic runners, and to identify factors that may influence the effects of FOs. Five databases (CINAHL, SPORTDiscus, MEDLINE, Embase, and Web of Science) were searched, resulting in 2536 studies. A total of 30 studies, published between 1992 and 2023 (730 symptomatic runners), were included following the removal of duplicates and the screening process. Wearing FOs while running is related to an immediate and a long-term decrease in pain and symptoms of overuse running injuries. Also, wearing FOs while running decreases eversion at the foot/ankle complex, leads to a more lateral plantar pressure at the heel and forefoot, and may change running motor control strategies. Finally, the effectiveness of FOs is influenced by its added features.

CONCLUSIONS

This study provides recommendations for future research such as the need for standardized methods in describing FOs, considering participant characteristics such as foot morphology, and comparing different types of FOs. Also, this scoping review provides valuable insights for guiding the prescription and design of FOs, and suggests that integrating FOs into a comprehensive treatment plan may yield better results than standalone first-line treatments. Nonetheless, this scoping review highlights the need for future research to explore the optimal integration of FOs into injury-specific treatment plans.

Lateral Femoral Condyle Stress Fracture in an Ultramarathoner: A Case Report

CASE

A 62-year-old ultramarathon athlete presented to the clinic with right posterolateral knee pain for 3 to 4 weeks and muscle tightness. Magnetic resonance imaging demonstrated a right lateral femoral condyle fracture. The fracture was treated conservatively, with return full Ironman competition 14 months later.

CONCLUSION

Femoral condyle fractures should be suspected in endurance athletes with nonspecific knee pain to prevent further injury. These fractures are rare, and more studies are needed to determine risk factors, risk classification, and optimal treatment protocol. With rising popularity of ultraendurance events, sports medicine physicians must educate patients on injury recognition and mitigation strategies.

Comparison of Weekly Training Load and Acute: Chronic Workload Ratio Methods to Estimate Change in Training Load in Running

CONTEXT

Before examining the impact of training load on injury risk in runners, it is important to gain insight into the differences between methods that are used to measure change in training load.

OBJECTIVE

To investigate differences between 4 methods when calculating change in training load: (1) weekly training load; (2) acute : chronic workload ratio (ACWR), coupled rolling average (RA); (3) ACWR, uncoupled RA; (4) ACWR, exponentially weighted moving average (EWMA).

DESIGN

Descriptive epidemiology study.

SETTING

This study is part of a randomized controlled trial on running injury prevention among recreational runners. Runners received a baseline questionnaire and a request to share global positioning system training data.

PATIENTS OR OTHER PARTICIPANTS

Runners who registered for running events (distances 10-42.195 km) in the Netherlands.

MAIN OUTCOME MEASURE(S)

The primary outcome measure was the predefined significant increase in training load (weekly training loads ≥ 30% progression and ACWRs ≥ 1.5), based on training distance. Proportional Venn diagrams visualized the differences between the methods.

RESULTS

A total of 430 participants (73.3% men; mean age = 44.3 ± 12.2 years) shared their global positioning system training data for a total of 22 839 training sessions. For the weekly training load, coupled RA, uncoupled RA, and EWMA method, respectively, 33.4% (95% CI = 32.8, 34.0), 16.2% (95% CI = 15.7, 16.6), 25.8% (95% CI = 25.3, 26.4), and 18.9% (95% CI = 18.4, 19.4) of the training sessions were classified as significant increases in training load. Of the training sessions with significant increases in training load, 43.0% from the weekly training load method were different than the coupled RA and EWMA methods. Training sessions with significant increases in training load based on the coupled RA method showed 100% overlap with the uncoupled RA and EWMA methods.

CONCLUSIONS

The difference in the change in training load measured by weekly training load and ACWR methods was high. To validate an appropriate measure of change in training load in runners, future research on the association between training loads and running-related injury risk is needed.

Using dynamic ultrasound to assess Achilles tendon mechanics during running: The effect on running pattern and muscle-tendon junction tracking

Achilles tendon strain can be quantified using dynamic ultrasound, but its use in running is limited. Minimal effects on running pattern and acceptable test-retest reliability of muscle-tendon junction (MTJ) tracking are prerequisites for ultrasound use during running. We aimed to assess (i) the effect of wearing an ultrasound transducer on running pattern and (ii) the test-retest reliability of MTJ tracking during running. Sixteen long-distance runners (nine injury-free, seven with Achilles tendinopathy) ran at different speeds on an instrumented treadmill with a 10-camera system tracking skin-mounted retroreflective markers, first without and then with an ultrasound transducer attached to the lower leg to track the MTJ of the gastrocnemius medialis. Spatiotemporal parameters, joint kinematics and kinetics were compared between conditions using mixed ANOVAs and paired t-tests. MTJ tracking was performed manually twice by three raters in ten participants. Variability and standard error of measurement (SEM) quantified the inter- and intra-tester test-retest reliability. The running pattern was not affected by wearing the ultrasound transducer, except for significantly less knee flexion during midstance (1.6°) and midswing (2.9°) found when wearing the transducer. Inter-rater and intra-rater SEMs for MTJ tracking to assess the tendon strain (0.43%, and 0.56%, respectively) were about four times as low as between-group differences presented in literature. The minimal effects found on the running pattern and acceptable test-retest reliability indicates that dynamic ultrasound during running can be appropriately used to study Achilles tendon mechanics and thereby help improve our understanding of Achilles tendon behavior during running, injury development and recovery.

Acute effects of the short-foot exercise in runners with medial tibial stress syndrome: A quasi-experimental study

OBJECTIVES

Analyze whether there are immediate changes in peak soleus activation and peak hindfoot eversion after short-foot exercise (SFE) in runners with medial tibial stress syndrome (MTSS). Secondarily, establish differences in peak soleus activation and peak hindfoot eversion between asymptomatic individuals and those presenting MTSS.

DESIGN

Quasi-experimental study.

SETTING

University Laboratory.

PARTICIPANTS

Thirty-two runners participated: 16 with MTSS and 16 in the no-pain group (NPG).

MAIN OUTCOME MEASURES

Soleus activation was measured using electromyography, and hindfoot eversion via 3D kinematic analysis. Participants performed SFE, and running data were collected at 9,12 and 15 km/h pre- and post-intervention.

RESULTS

SFE reduced peak soleus activation at 9 (p = 0.017) and 15 km/h (p = 0.019) for the MTSS group and at 15 km/h (p < 0.001) for the NPG, suggesting improved neuromuscular efficiency and potentially reduced tibial stress. SFE did not significantly affect peak hindfoot eversion. Significant correlations were found between ankle dorsiflexion range of motion and muscle activation (r = 0.585 to 0.849, p < 0.05). These findings suggest SFE could improve neuromuscular efficiency and reduce tibial stress, and highlights ankle flexibility's role in muscle activation.

CONCLUSIONS

SFE significantly reduces soleus activation, potentially improving neuromuscular efficiency and decreasing tibial stress.

The Impact of Blood Flow Restriction Training on Tibial Bone Stress Injury Rehabilitation: An Exploratory Case Series

Background

Lower extremity bone stress injuries (BSI) are common injuries among athletes and military members. Typical management involves a period of restricted weightbearing which can have rapid detrimental effects upon both muscle and bone physiology. Few studies have investigated the effect of blood flow restriction (BFR) training on bone in the rehabilitative setting.

Purpose

The purpose of this study was to investigate the effects of lower extremity exercise with the addition of BFR upon bone mineral density, bone mineral content, and lean body mass in military members with tibial BSIs.

Study Design

Case series.

Methods

Twenty military members with MRI-confirmed tibial BSI were recruited to complete lower extremity exercise with the addition of BFR twice per week for four weeks. The BFR cuff was applied proximally to the participant's involved limb while they performed gluteal, thigh, and leg resistance exercises. Outcomes were assessed at baseline and four weeks. The primary outcomes were whole leg bone mineral density (BMD), bone mineral content (BMC), and lean body mass (LM) as measured by dual-energy x-ray absorptiometry. Secondary outcomes included thigh and leg circumference measures and patient-reported outcomes, including the Lower Extremity Functional Scale (LEFS), Patient-Reported Outcomes Measurement Information System 57 (PROMIS-57), and Global Rating of Change (GROC).

Results

No significant differences were found in BMD (p=0.720) or BMC (p=0.749) between limbs or within limbs over time. LM was generally less in the involved limb (p=0.019), however there were no significant differences between or within limbs over time (p=0.404). For thigh circumference, significant main effects were found for time (p=0.012) and limb (p=0.015), however there was no significant interaction effect (p=0.510). No significant differences were found for leg circumference (p=0.738). Participants showed significant mean changes in LEFS (15.15 points), PROMIS physical function (8.98 points), PROMIS social participation (7.60 points), PROMIS anxiety (3.26 points), and PROMIS pain interference (8.39 points) at four weeks.

Conclusion

The utilization of BFR in the early rehabilitative management of tibial BSI may help mitigate decrements in both bone and muscle tissue during periods of decreased physical loading.

Level of Evidence

4.

The Dogma of Running Injuries: Perceptions of Adolescent and Adult Runners

CONTEXT

Adults perceive certain factors to increase or decrease the risk of sustaining running-related injuries, but many of their perceptions are not supported by research. Little is known about the perceptions that adolescent runners hold. Investigating perceptions for adolescent runners is needed to assist in the development of future injury educational materials, as these resources may need to be tailored differently for adolescents and adults.

OBJECTIVE

To identify factors that adolescent runners perceive as risk or protective factors for running-related injuries and to compare these perceptions with those of adult runners.

DESIGN

Cross-sectional study.

SETTING

Online survey.

PATIENTS OR OTHER PARTICIPANTS

We surveyed 302 adolescent (164 females, 138 males; age = 16.0 ± 1.4 years [range, 12-19 years]) and 357 adult runners (197 women, 160 men; age = 40.7 ± 11.8 years [range, 20-77 years]).

MAIN OUTCOME MEASURE(S)

Participants completed a survey with questions about whether factors related to training habits, footwear, biomechanics, strength, stretching, or nutrition influence the risk of sustaining a running-related injury. If ≥75% of adolescents indicated that a factor increases or decreases the risk of sustaining an injury, we considered that factor to be a perceived risk or protective factor, respectively. We also performed Fisher's exact test to compare the proportion of adolescent and adult runners who responded with "increase," "decrease," "neither increase or decrease," or "I don't know" to each question.

RESULTS

Adolescent runners perceived training habits, footwear, biomechanics, strength, stretching, and nutrition to increase or decrease the risk of sustaining a running-related injury. A larger proportion of adolescents than adults perceived that more footwear cushioning and stretching decrease injury risk, but a smaller proportion perceived that overtraining increases injury risk and strength decreases injury risk.

CONCLUSIONS

Differences in perceptions exist between adolescent and adult runners, and future educational materials and research questions may need to be tailored for different running populations.

MRI and single-cell RNA sequence results reveal the influence of anterior talofibular ligament injury on osteochondral lesions of the talus

Anterior talofibular ligament injuries and osteochondral lesions of the talus present unique challenges to orthopedic surgeons. This study aimed to investigate the relevant relationship between them by analyzing the Magnetic resonance imaging (MRI) results of clinical patients and single-cell RNA sequence (scRNA seq) results of healthy talus cartilage to discuss the risk factors. Data from 164 patients from 2018 to 2023 was retrospectively analyzed. The correlation analysis between ATFL injury grade and the Hepple stage of OLT determined by MRI was performed. Publicly available single-cell RNA datasets were collected. Single-cell RNA datasets from five volunteers of healthy talus cartilage were analyzed. ATFL injury grade was relevant with the Hepple stage of OLT (P < 0.05). The results of multivariate logistic regression analysis showed that injured area was the independent influencing factor of the incidence rate and the severity of OLT (P < 0.05). The Hepple stage of OLT was relevant with AOFAS and VAS (P < 0.05). Single-cell RNA sequence results showed that among the 9 subtypes of chondrocytes, the interaction strength between HTC-A and HTC-B is the highest. Their physical interactions are mainly achieved through the CD99 signaling pathway, and factor interactions are mainly achieved through the ANGPTL signaling pathway. Anterior talofibular ligament injury may lead to osteochondral lesions of the talus. Early medical intervention should be carried out for ligament injuries to restore joint stability and avoid cartilage damage.

Immediate effect of the use of toe separators on dynamic balance and ankle range of motion: a pilot study

BACKGROUND AND OBJECTIVES

Injuries involving ankle stability and range of motion are among the most frequent in athletes and in the general population. In response, this study aimed to assess the immediate effects of toe separators on dynamic stability and ankle range of motion in healthy young individuals.

METHODS

Among the 68 eligible participants, 50 healthy and active subjects completed all trials. The impact of the intervention was evaluated using the Weight Bearing Lunge Test and Y-Test. The control condition performed the tests without toe separators, while the experimental condition performed the tests with toe separators. All participants performed both conditions with a wash-out period of at least 7 days between trials.

RESULTS

Statistical analysis revealed no significant differences in dynamic balance (p > 0.05) and range of motion (p > 0.05) between the two conditions. Additionally, no asymmetries were detected between the lower limbs in both tests (p > 0.05).

CONCLUSIONS

The results of this pilot study indicate that using toe separators does not have an immediate effect on ankle range of motion and dynamic balance in young, healthy individuals. Future research should consider evaluating intervention programs of longer duration and exploring different populations.

Predictive Value of the KOJI AWARENESS Self-Evaluation System for Running Injuries in Elite Male Long-Distance Runners: A Prospective Cohort Study

Background

The KOJI AWARENESS (KA) test is a practical self-evaluation tool that assesses body movements and may help develop individual conditioning plans to improve movement function. However, the association between preseason KA scores and in-season injury occurrence remains unexplored.

Purpose

To investigate whether the KA self-screening test score can predict running-related injuries in elite long-distance runners.

Study Design

Cohort study; Level of evidence, 2.

Methods

A total of 47 elite college male long-distance runners (age, 18-22 years) were enrolled in this study in June 2022. The participants underwent the KA self-screening test to assess preseason upper limb, core, and lower limb function. Running-related injuries with a training time loss of >3 weeks were tracked for 6 months during the season. The participants were divided into injury and noninjury groups, and between-group comparisons and receiver operating characteristic (ROC) curve analysis were used to determine the association between the KA scores and the injury incidence. Chi-square tests and risk ratios were calculated based on the cutoff value- and injury-based grouping.

Results

Among the runners, 10 (21.3%) sustained an injury. There were no significant differences in the demographic characteristics between the injury and noninjury groups. The injury group had significantly lower KA scores than the noninjury group (median, 44.5 [interquartile range, 43-46.8] vs median, 48 [interquartile range, 46-50], respectively; P = .009). The ROC curve analysis determined a cutoff value of 46.5 points (sensitivity, 73%; specificity, 63.6%), indicating that the KA scores exhibited a relatively high predictive value for running-related injuries (area under the ROC curve, 0.764 [95% CI, 0.600-0.930]). The risk ratio for group division based on the cutoff value was 2.590 (95% CI, 1.329-5.047).

Conclusion

These findings demonstrated that the KA test is an effective self-screening tool for predicting the risk of running-related injuries in elite male long-distance runners.

An Investigation Into the Measurement of Injury Severity in Running-Related Injury Research: A Scoping Review

Understanding injury severity is essential to inform injury prevention practice. The aims of this scoping review were to investigate how running-related injury (RRI) severity is measured, compare how it differs across studies, and examine whether it influences study outcomes (i.e., injury rates and risk factor identification). This scoping review was prospectively registered with Open Science Framework. A systematic electronic search was conducted using PubMed, Scopus, SPORTDiscuss, MEDLINE, and Web of Science databases. Included studies were published in English between January 1980 and December 2023, investigated RRIs in adult running populations, and included a measure of injury severity. Results were extracted and collated. Sixty-six studies were included. Two predominant primary criteria are used to define injury severity: the extent of the effect on running and/or the extent of the physical description. When secondary definition criteria are considered, 13 variations of injury severity measurement are used. Two approaches are used to grade injury severity: a categorization approach or a continuous numerical scale. Overall, the measurement of RRI severity is relatively inconsistent across studies. Less than half of studies report incidence rates per level of injury severity, while none report specific risk factors across levels, making it difficult to determine if the approach to measuring injury severity influences these study outcomes. This lack of information is possibly contributing to inconsistent rates of RRIs reported, and the lack of clarity on risk factors.

Current iliotibial band syndrome alters patterns of running coordination in male and female runners, but not their levels of coordination variability

The aim of the present study was to compare the coordination patterns and levels of coordination variability of healthy and injured runners with iliotibial band syndrome (ITBS). Sixty runners divided into four groups (15 healthy males, 15 healthy females, 15 males with ITBS and 15 females with ITBS) ran at a steady and freely chosen pace on an over-ground track, and their coordination patterns of the lower limbs were calculated during 10 running stances using the vector coding technique. Both male and female runners with ITBS showed a greater dominance of the pelvis segment and the anti-phase patterns in the frontal plane thigh-pelvis coupling (p = 0.001, η2 = 0.36). In addition, injured female runners showed a greater hip adduction dominance, whereas injured males presented a greater anti-phase pattern in the transverse plane-frontal plane hip coupling (p = 0.003, η2 = 0.08). The levels of coordination variability during running stance did not change between ITBS injured and healthy runners in any of the couplings. Currently injured runners with ITBS appeared to present altered coordination patterns on the hip couplings that were partly dependent on gender but did not lead to changes in the coordination variability levels.

Enhancing running injury prevention strategies with real-time biofeedback: A systematic review and meta-analysis

The number of runners and the incidence of running-related injuries (RRIs) are on the rise. Real-time biofeedback gait retraining offers a promising approach to RRIs prevention. However, due to the diversity in study designs and reported outcomes, there remains uncertainty regarding the efficacy of different forms of feedback on running gait biomechanics. Three databases: MEDLINE, PUBMED, and SPORTDiscus were searched to identify relevant studies published up to March 2024, yielding 4646 articles for review. The quality of the included studies was assessed using the Downs and Black Quality checklist. Primary outcomes, including Peak Tibial Acceleration (PTA), Vertical Average Loading Rate (VALR), and Vertical Instantaneous Loading Rate (VILR), were analysed through meta-analysis. 24 studies met the inclusion criteria and were analysed in this review.17 used visual biofeedback (VB) while 14 chose auditory biofeedback (AB). The meta-analysis revealed a reduction in loading variables both immediately following the intervention and after extended training, with both visual and auditory feedback. Notably, the decrease in loading variables was more pronounced post-training and VB proved to be more effective than AB. Real-time biofeedback interventions are effective in lowering loading variables associated with RRIs. The impact is more substantial with sustained training, and VB outperforms AB in terms of effectiveness.

Prevalence and Risk Factors for Musculoskeletal Pain when Running During Pregnancy: A Survey of 3102 Women

BACKGROUND

Musculoskeletal pain while running is a concern to women during pregnancy and can lead to running cessation. To support women who wish to run during pregnancy, it is essential to understand the sites, severities and personal risk factors associated with musculoskeletal pain.

OBJECTIVE

The aim was to investigate prevalence and risk factors for musculoskeletal pain when running during pregnancy.

METHODS

An online survey was completed by women who had a child in the past 5 years and ran prior to and during pregnancy. Pain frequency informed prevalence rates by body site, and logistic regression odds ratios (ORs) and 95% confidence intervals were calculated.

RESULTS

A total of 3102 women of 23 ethnicities from 25 countries completed the survey. Women were 22-52 years old when they gave birth and ran 2-129 km/week during the 0.5-35 years before the birth of their youngest child. Women ran significantly less distance and less often during pregnancy than before pregnancy. Most women (86%) experienced pain while running during pregnancy (59% pelvis/sacroiliac joint, 52% lower back, 51% abdomen, 44% breast, 40% hip). The highest prevalence of severe-to-worst pain was at the pelvis/sacroiliac joint (9%). Women at greatest risk of pain while running during pregnancy had a previous injury (OR = 3.44) or were older (OR = 1.04). Women with a previous child were less likely to experience breast pain (OR = 0.76) than those running during their first pregnancy.

CONCLUSION

Healthcare practices to reduce pain should focus on regions of greatest musculoskeletal change during pregnancy, specifically the pelvis, lower back and abdomen. Efforts to support women to run for longer throughout pregnancy should focus on pain at the pelvis and breasts.

Effectiveness of Percutaneous Needle Electrolysis to Reduce Pain in Tendinopathies: A Systematic Review With Meta-Analysis

CONTEXT

Tendon injuries are common disorders in both workers and athletes, potentially impacting performance in both conditions. This is why the search for effective treatments is continuing.

OBJECTIVE(S)

The objective of this study was to analyze whether the ultrasound-guided percutaneous needle electrolysis technique may be considered a procedure to reduce pain caused by tendinosis.

EVIDENCE ACQUISITION

The search strategy included the PubMed, SCOPUS, CINAHL, Physiotherapy Evidence Database, SciELO, and ScienceDirect up to the date of February 25, 2024. Randomized clinical trials that assessed pain caused by tendinosis using the Visual Analog Scale and Numeric Rating Scale were included. The studies were evaluated for quality using the Cochrane Risk of Bias 2, and the evidence strength was assessed by the GRADEpro GDT.

EVIDENCE SYNTHESIS

Out of the 534 studies found, 8 were included in the review. A random-effects meta-analysis and standardized mean differences (SMD) were conducted. The ultrasound-guided percutaneous needle electrolysis proved to be effective in reducing pain caused by tendinosis in the overall outcome (SMD = -0.97; 95% CI, -1.26 to -0.68; I2 = 58%; low certainty of evidence) and in the short-term (SMD = -0.83, 95% CI, -1.29 to -0.38; I2 = 65%; low certainty of evidence), midterm (SMD = -1.28; 95% CI, -1.65 to -0.91; I2 = 0%; moderate certainty of evidence), and long-term (SMD = -0.94; 95% CI, -1.62 to -0.26; I2 = 71%; low certainty of evidence) subgroups.

CONCLUSION(S)

The application of the ultrasound-guided percutaneous needle electrolysis technique for reducing pain caused by tendinosis appears to be effective. However, due to the heterogeneity found (partially explained), more studies are needed to define the appropriate dosimetry, specific populations that may benefit more from the technique, and possible adverse events.

Do we underestimate the frequency of ankle sprains in running? A systematic review and meta-analysis

OBJECTIVE

To provide a systematic review and meta-analysis of the proportion of ankle sprains in running practices.

DESIGN

Systematic review and meta-analysis.

MAIN OUTCOME MEASURES

We calculated the weighted summary proportion and conducted meta-analyses for runners, considering levels (elite/recreational) and disciplines (distance, track, cross-country, trail, and orienteering).

RESULTS

32 studies were included in the systematic review and 19 were included in the meta-analysis with a level of quality ranging from poor to good. Proportion of ankle sprains in runners was 13.69% (95%CI = 7.40-21.54; I2 = 98.58%) in global, 12.20% (95%CI = 5.24-21.53; I2 = 89.31%) in elite, 19.40% (95%CI = 10.05-30.90; I2 = 99.09%) in recreational, 8.51% (95%CI = 4.22-14.12; I2 = 96.15%) in distance, 67.42% (95%CI = 0.50-82.85; I2 = 99.36%) in track, 27.07% (95%CI = 12.48-44.81; I2 = 97.97%) in cross-country, and 25.70% (95%CI = 19.87-32.14; I2 = 0.00) in orienteering.

CONCLUSIONS

Running practice results in significant proportion rate of ankle sprains. Recreational runners exhibit higher proportion than elite. Running disciplines, especially track, cross-country, and orienteering, influence reported ankle sprain rates, surpassing those of distance runners.

Evaluating Compliance With the Ottawa Rules: A Retrospective Clinical Audit at a District General Hospital in the UK

BACKGROUND

The Ottawa Rules are clinical decision tools designed to assist healthcare providers in determining the need for radiographs in patients with ankle or knee injuries. Compliance with these rules can lead to more efficient use of resources and reduced radiation exposure.

OBJECTIVE

This retrospective clinical audit aimed to evaluate healthcare provider's compliance with the Ottawa Rules in an Emergency Department setting and assess the positivity rates of requested knee and ankle X-rays.

METHODS

A two-cycle retrospective audit was conducted at Lincoln County Hospital's Emergency Department, involving 648 X-rays collected in two cycles. In between, multiple interventions were implemented to improve the outcomes.

RESULTS

The study revealed varying levels of compliance with the Ottawa Rules, with higher compliance observed for knee X-rays than ankle X-rays. The compliance for knee X-rays improved from 74.6% to 89.9% and ankle X-rays improved from 33.1% to 75.8%. Positivity rates for ankle radiographs were higher than knee radiographs in both cycles. The interventions implemented between the cycles significantly improved compliance rates with the Ottawa Rules.

CONCLUSION

The findings underscore the importance of adherence to the Ottawa Rules in optimizing patient care and resource utilization. The study suggests the need for continued education and periodic audits to maintain and further improve compliance rates. Additionally, the higher positivity rates for ankle radiographs highlight the importance of targeted imaging strategies based on clinical guidelines.

Demographics, culture and participatory nature of multi-marathoning-An observational study highlighting issues with recommendations

OBJECTIVES

The defining achievement of a multi-marathoner is completing 100 marathons. This study aimed to comprehensively document the phenomenon of multi-marathoning, addressing its demographics, culture and participatory nature, filling a gap in peer-reviewed research on the topic. Additionally, it aimed to provide recommendations for multi-marathon governing bodies, event organisers, health professionals and participants to address identified issues.

METHODS

A global survey was distributed to participants and individuals interested in multi-marathoning. It was distributed with support from major national and international multi-marathon clubs through their social media channels, email groups and newsletters. The survey was conducted anonymously and online.

RESULTS

The survey garnered responses from 830 participants across 40 countries, with an average marathon completion count of 146.54 (SD 201.83) per respondent. Gender distribution showed 60.69% men, 39.3% women and 0.1% gender variant/non-conforming. Respondents' average ages were 51.6 (SD 9.96) years for men, 48.83 (SD 9.15) years for women and 35.00 (SD 8.76) years for gender variant/non-conforming. As participants age, social and travel motivations surpass competitiveness. A majority (57%) of respondents had at least one contravention to the pre-participation screening questionnaire PARQ-+ and 67% reported taking pain relief medication around events. Notably, 93% of respondents reported multi-marathoning as beneficial for their mental health.

DISCUSSION

Multi-marathoning accommodates older athletes, but a significant gender imbalance exists in participation levels. Long-term health implications warrant attention from governing bodies, event organisers, health professionals and participants alike. Multi-marathoners should seek medical advice before participation, utilise modern equipment for health monitoring and optimise training accordingly.

CONCLUSION

Recommendations include encouraging diversity at events, ensuring event directors have well-resourced health plans and promoting participants' proactive health management before and during their involvement in the sport. This study not only advances our understanding of multi-marathoning as a sport but also contributes to theoretical frameworks such as SDT and HBM.

Prevalence of Sonographic Achilles Tendon, Patellar Tendon, and Plantar Fascia Abnormalities in Division I Collegiate Athletes From a Variety of Sports

OBJECTIVE

This study aimed to determine the prevalence of ultrasound abnormalities in the Achilles tendon, patellar tendon, and plantar fascia among a large cohort of collegiate student-athletes.

DESIGN

Observational cross-sectional study.

SETTING

Three Division I institutions.

PARTICIPANTS

243 student-athletes participated in this study. Exclusion criteria included those younger than 18 years or who underwent prior surgery/amputation of structures, including anterior cruciate ligament (ACL) surgeries with patellar tendon grafts.

INTERVENTIONS

Ultrasound examination of the Achilles tendon, patellar tendon, and plantar fascia of each leg was performed. An experienced sonographer reviewed each tendon video in a blinded manner, with a separate experienced sonographer separately reviewing to establish inter-rater reliability.

MAIN OUTCOME MEASURES

The primary outcome measured was the presence of any sonographic abnormality including hypoechogenicity, thickening, or neovascularity.

RESULTS

Ultrasound abnormalities were identified in 10.1%, 37.2%, and 3.9% of all Achilles tendons, patellar tendons, and plantar fasciae, respectively. Abnormalities were significantly associated with the presence of concurrent pain for all structures ( P < 0.01). Specifically, athletes with sonographic abnormalities were approximately 4 times [relative risk (RR) = 4.25; 95% confidence interval (CI), 2.05-8.84], 6 times (RR = 5.69; 95% CI, 2.31-14.00), and 5 times (RR = 5.17; 95% CI, 1.76-15.25) more likely to self-report pain in the Achilles tendon, patellar tendon, and plantar fascia, respectively.

CONCLUSIONS

This multi-institutional study completed at 3 Division I institutions is the largest study of its kind to identify the prevalence of sonographic abnormalities in the Achilles tendon, patellar tendon, and plantar fascia among collegiate student-athletes of various sports.

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.

The Effects of Lower Leg Compression Garments on Lower Extremity Sports Injuries, Subjective Fatigue and Biomechanical Variables: A Systematic Review with Meta-analysis

The objective of this study was to systematically review the literature on the effect of CGs versus non-CGs (such as regular socks) or versus placebo garments on 1) the incidence of lower extremity sports injuries and 2) subjective ratings of fatigue and biomechanical variables in athletes at participating in any sport that required any level of running performance, given that fatigue-related biomechanical alterations may increase the risk of sports injuries. This study was a systematic review with meta-analyses. PubMed, Embase, CINAHL, Cochrane, PEDro, and Scopus were searched for eligible studies until 7 July 2021. Two reviewers independently assessed the risk of bias using the Cochrane Collaboration's tool for risk of bias. Meta-analyses were performed using a random-effects model. The Grades of Recommendation, Assessment, Development and Evaluation (GRADE) approach was used to assess the certainty of evidence for all outcome measures. Twenty-three studies, all with a high risk of bias, were included. Nineteen studies were used in the meta-analyses. No studies focused on the effect of CGs on the incidence of lower extremity sports injuries in athletes. Seventeen studies investigated the effect of CGs on subjective ratings of fatigue, but meta-analysis showed no difference in effectiveness between CGs versus non-CGs (such as regular socks) and versus placebo CGs (low certainty evidence). Because of heterogeneity, pooling of the results was not possible for the biomechanical variables. Nonetheless, low certainty evidence showed no effect of CGs. We identified no evidence for a beneficial or detrimental effect of lower leg CGs on the occurrence of lower extremity sports injuries, subjective ratings of fatigue, or biomechanical variables in athletes at any level of running performance. Based on the variable use of running tests, definitions used for biomechanical variables, and reporting of CG characteristics and more standardized reporting is recommended for future studies evaluating CGs.

Return to Play in the Professional Athlete

The management of any injury in elite athletes poses unique challenges distinct from the general population because the goal is rapid recovery and return to play (RTP) while simultaneously managing residual symptoms and minimizing risk of reinjury. The time required for treatment, recovery, and return to peak performance can have consequences for both the athlete and his or her team: financial implications, psychological stressors, team dynamics, and future performance. RTP after an injury in the professional athlete requires a complex decision-making process with many stakeholders. Several factors influence this decision, not the least of which is the type and mechanism of injury. This article provides an overview of the RTP process including nonmedical factors that may influence this decision, common injuries seen in professional athletes, injury patterns particular to certain popular sports, and imaging guidelines for such injuries.

Immediate Effects of Instrument-Assisted Soft-Tissue Mobilization Versus Dry Needling on Trigger Point Pain and Tightness of Calf Muscles in Long-Distance Runners

Introduction Muscle tightness is frequently identified as a potential precursor to muscle injuries. Reclaiming flexibility and enhancing range of motion (ROM) is crucial for preventing injuries and achieving improvements in performance. The present study examines the immediate effects of instrument-assisted soft-tissue mobilization (IASTM) and dry needling (DN) in reducing trigger point pain and calf tightness in long-distance runners. Methodology A total of 40 long-distance runners were recruited in the study (30 males and 10 females). The procedure was performed under the author's surveillance at the sports complex. These recruited players were placed into two groups: the IASTM (n=20) and the DN (n=20) group. The outcome measures used were the pressure algometer for assessing pain pressure threshold and the lunge test. An iPhone Measure app (Measure app, Apple App Store 2023) is used to assess ankle dorsiflexion ROM. The evaluation took place both prior to and immediately following the intervention and 48 hours after the intervention. Result The analysis within each group revealed a significant alteration in pain pressure threshold for both the IASTM and DN groups (p≤0.05), along with a relative enhancement in ankle dorsiflexion ROM observed in the IASTM group (p≤0.05). Between-group analysis revealed a notable difference with an effect size difference of Cohen's d=1.06 (large difference) in pain pressure threshold, d=0.21 (small difference) in lunge test, and d=0.57 (medium difference) in ankle dorsiflexion ROM. Conclusion The present study concludes that both groups, IASTM and DN, showed significant effects in improving pain pressure threshold in long-distance runners. However, DN showed better results. IASTM showed significant results in enhancing the ankle dorsiflexion ROM immediately. This implies that it can be used in conjunction with stretching to decrease pain and enhance flexibility, hence improving performance and preventing injuries.

Pain and disability were related to Y-balance test but not with proprioception acuity and single-leg triple-hop test in patients with patellofemoral pain: A cross-sectional study

INTRODUCTION

Patellofemoral pain is a common complaint between physically active subjects. Patients with patellofemoral pain present limitations to performing daily activities. Pain could alter proprioceptive acuity and lead to movement impairment. The aim of this study was to investigate the relationship of pain and disability with proprioception acuity and physical performance in patients with patellofemoral pain.

METHODS

Forty-eight patients with patellofemoral pain [age 31.15 (5.91) years; 30 (62.50%) males] were recruited. Data collected included pain intensity, pain duration, disability, joint position sense (JPS) test at 20° and 60° of knee flexion, and physical performance tests (Single-Leg Triple-Hop Test and Y- Balance Test). Spearman's rank correlation coefficient (rs) and 95% confidence intervals (CI) were computed to assess the relationship between the variables.

RESULTS

Pain intensity was correlated with Y-Balance Test posteromedial component (rs = -0.32, 95%CI = -0.55 to -0.03, p = 0.029) and the composite score (rs = -0.35, 95%CI = -0.58, -0.07, p = 0.015). Pain duration was correlated with Y-Balance Test posterolateral component (rs = -0.23, 95% CI = -0.53 to -0.01, p = 0.047). Disability was correlated with Y-Balance Test posteromedial component (rs = 0.41, 95% CI = 0.14 to 0.62, p = 0.004). Pain and disability were not correlated with JPS and the Single-Leg Triple-Hop Test.

CONCLUSION

Pain and disability were related to Y-Balance Test but not to proprioceptive acuity and Single-Leg Triple-Hop Test in patients with patellofemoral pain.

Diffusion tensor imaging combined with chemical shift-encoded sequence to quantify the adaptive changes of calf muscles in amateur marathoners

PURPOSE

Calf muscles play an important role in marathon race, and the incidence of injury is high in this process. This study prospectively quantified diffusion tensor metrics, muscle fat fraction (MFF) and cross-sectional area (CSA) of calf muscles induced by endurance exercise in amateur marathoners, and the potential mechanisms underlying the changes in these parameters were analyzed.

METHOD

In this prospective study, 35 marathoners (27 males, 8 females; mean age (standard deviation, SD), 38.92 (4.83) years) and 26 controls (18 males, 8 females; mean age (SD), 38.35 (6.75) years) underwent magnetic resonance imaging (MRI) from September 2022 to March 2023. The diffusion tensor eigenvalues (λ1, λ2, λ3), radial diffusivity (RD), fractional anisotropy (FA), MFF and CSA of calf muscles were compared between marathoners and controls. A binary logistic regression model with gender correction was performed analyze the relationship between marathon exercise and DTI parameters, CSA and MFF of calf muscles.

RESULTS

Interobserver agreement was good (κ = 0.71). The results of binary logistic regression model with gender correction showed that the regression coefficients of FA values in anterior group of calf (AC), soleus (SOL), medial gastrocnemius (MG) and lateral gastrocnemius (LG) were negative, and the odds ratios (OR) were 0.33, 0.45, 0.35, 0.05, respectively (P < 0.05). The OR of RD in SOL and λ2 in external group of calf (EC) were relatively higher, 3.74 and 3.26, respectively (P < 0.05). CSA was greater in SOL of marathoners, with an OR value of 1.00(P < 0.05). The MFF in AC and LG was lower in marathoners and OR of two indexes were -0.69 and -0.59, respectively (P < 0.05).

CONCLUSIONS

Diffusion tensor imaging (DTI) combined with chemical shift-encoded sequence can noninvasively detect and quantify the adaptive changes of calf muscle morphology, microstructure and tissue composition induced by long-term running training in amateur marathoners.

Injury patterns and healthcare utilisation by runners of the New York City Marathon

Objectives

The purpose of this study was to describe injury patterns and healthcare utilisation of marathon runners.

Methods

This was a previously reported 16-week prospective observational study of runners training for the New York City Marathon. Runners completed a baseline survey including demographics, running experience and marathon goal. Injury surveys were collected every 4 weeks during training, as well as 1 week before and 1 week after the race. Injury details collected included anatomic location, diagnosis, onset, and treatment received.

Results

A total of 1049 runners were enrolled. Injuries were reported by 398 (38.4%) during training and 128 (14.1%) during the marathon. The overall prevalence of injury was 447/1049 (42.6%). Foot, knee and hip injuries were most common during training, whereas knee, thigh and foot injuries were most common during the race. The most frequent tissue type affected was the category of muscle, tendon/fascia and bursa. The prevalence of overuse injuries increased, while acute injuries remained constant throughout training. Hamstring injuries had the highest prevalence of diagnosis with 38/564 injuries (6.7%). Of the 447 runners who reported an injury, 224 (50.1%) received medical care. Physical therapy was the most common medical care received with 115/1037 (11.1%) runners during training and 44/907 (4.9%) postrace.

Conclusion

Runners training and participating in a marathon commonly experience injuries, especially of the foot and knee, which often are overuse soft tissue injuries. Half of the injured runners sought out medical care for their injury. Understanding the patterns of injuries affecting marathon runners could help guide future injury prevention efforts.

Clinical and exercise professional opinion of return-to-running readiness after childbirth: an international Delphi study and consensus statement

Female athletes have identified a lack of guidance as a barrier to successfully returning to running postpartum, and existing guidelines are vague. Our aim was to define the current practice of determining postpartum run-readiness through a consensus survey of international clinicians and exercise professionals in postpartum exercise to assist clinicians and inform sport policy changes.A three-round Delphi approach was used to gain international consensus from clinicians and exercise professionals on run-readiness postpartum. Professionals who work with postpartum runners participated in an online survey to answer open-ended questions about the following postpartum return-to-running topics: definitions (runner and postpartum), key biopsychosocial milestones that runners need to meet, recommended screening, timeline to initiate running, support items, education topics and factors that contribute to advising against running. Consensus was defined as ≥75% participant agreement.One hundred and eighteen professionals participated in round I, 107 participated in round II (response rate 90.6%) and 95 participated in round III (response rate 80.5%). Responses indicated that, following a minimum 3-week period of rest and recovery, an individualised timeline and gradual return to running progression can be considered. Screening for medical and psychological concerns, current physical capacity, and prior training history is recommended prior to a return to running.This study proposes recommendations for the initial guidance on return-to-running postpartum, framed in the context of current research and consensus from professionals. Future research is needed to strengthen and validate specific recommendations and develop guidelines for best practice when returning-to-running after childbirth.

Acute effects of negative heel shoes on perceived pain and knee biomechanical characteristics of runners with patellofemoral pain

BACKGROUND

To determine the effects of negative heel shoes on perceived pain and knee biomechanical characteristics of runners with patellofemoral pain (PFP) during running.

METHODS

Sixteen runners with PFP ran in negative (-11 mm drops) and positive (5 mm drops) heel shoes while visual analog scale (VAS) scores, retroreflective markers, and ground reaction force were acquired by applying a 10-cm VAS, infrared motion capture system, and a three-dimensional force plate. Knee moment, patellofemoral joint stress (PFJS), and other biomechanical parameters during the stance phase were calculated based on inverse dynamics and a biomechanical model of the patellofemoral joint.

RESULTS

The foot inclination angle, peak PFJS during the stance phase, patellofemoral joint reaction force, knee extension moment, and quadriceps force at the time of peak PFJS of runners with PFP in negative heel shoes were lower than that in positive heel shoes, no significant difference was found in VAS scores, knee flexion angle, patellofemoral contact area, and quadriceps moment arm at the time of peak PFJS.

CONCLUSIONS

Compared to positive heel shoes, running in negative heel shoes decreases peak PFJS in runners with PFP, which may decrease patellofemoral joint loading, thus reducing the possibility of further development of PFP.

TRAIL REGISTRATION

Sports Science Experiment Ethics Committee of Beijing Sport University. 2023095H, April 18, 2023 (prospectively registered).

Biomechanical Effect on Jack's Test on Barefoot Position, Regular Socks, and Biomechanics Socks

The proper dorsal flexion movement of the first metatarsophalangeal joint (MTPJ) is crucial for an accurate gait. Restricted movement can disrupt the windlass mechanism, and Jack's test is a tool to assess such alterations. Although running socks are commonly used, their influence on the windlass mechanism remains unclear. Therefore, the aim of this study was to measure the resistance to passive dorsal flexion of the first metatarsophalangeal joint (MTPJ) under three different conditions: barefoot, wearing regular socks, and wearing biomechanical socks, using a digital force gauge.

METHODS

The research involved a sample size of 30 subjects (14 men and 16 women), and Jack's test was conducted using a digital force gauge and a lever system. Three conditions were measured, barefoot, with a regular sock, and with the biomechanical socks.

RESULTS

Statistically significant differences were observed when using biomechanical socks with orthopedic corrections during Jack's test, as measured with the digital force gauge (13.33 N ± 3.54, p < 0.001).

CONCLUSIONS

The utilization of biomechanical socks with a kinetic wedge, reinforced mesh in the medial longitudinal arch, and padding in the heel area results in a reduction of the force required, measured in newtons, to perform dorsal flexion of the first metatarsophalangeal joint (MTPJ) during Jack's test compared to being barefoot or wearing regular socks.

Exercise-induced Musclin determines the fate of fibro-adipogenic progenitors to control muscle homeostasis

The effects of exercise on fibro-adipogenic progenitors (FAPs) are unclear, and the direct molecular link is still unknown. In this study, we reveal that exercise reduces the frequency of FAPs and attenuates collagen deposition and adipose formation in injured or disused muscles through Musclin. Mechanistically, Musclin inhibits FAP proliferation and promotes apoptosis in FAPs by upregulating FILIP1L. Chromatin immunoprecipitation (ChIP)-qPCR confirms that FoxO3a is the transcription factor of FILIP1L. In addition, the Musclin/FILIP1L pathway facilitates the phagocytosis of apoptotic FAPs by macrophages through downregulating the expression of CD47. Genetic ablation of FILIP1L in FAPs abolishes the effects of exercise or Musclin on FAPs and the benefits on the reduction of fibrosis and fatty infiltration. Overall, exercise forms a microenvironment of myokines in muscle and prevents the abnormal accumulation of FAPs in a Musclin/FILIP1L-dependent manner. The administration of exogenous Musclin exerts a therapeutic effect, demonstrating a potential therapeutic approach for muscle atrophy or acute muscle injury.

A One Session Gait Retraining Protocol with Metronome Augmentation Increases Cadence in Novice and Recreational Runners

Background

Running is a common leisure physical activity that carries a risk for running related injury (RRI). Non-experienced runners are more likely to sustain RRIs. One form of gait retraining focuses on increasing cadence to improve running biomechanics related to RRI. Protocols for increasing cadence must be pragmatic to be implemented into clinical practice.

Hypothesis/Purpose

The purpose of this study was to determine if a pragmatic protocol including one instructional session, followed by independent gait retraining with metronome augmentation resulted in increased cadence and altered biomechanics in novice and recreational runners.

Study Design

Randomized Controlled Trial.

Methods

Thirty-three novice or recreational adult runners completed a 12 Minute Cooper Run on an indoor track. Variables measured during the 12 Minute Cooper Run included distance, rate of perceived exertion (RPE), heart rate (HR), and 3-D biomechanics using inertial measurement units (IMUs). After baseline testing, the intervention group received instruction and five minutes of gait retraining at a cadence set 5-10% higher than baseline with metronome augmentation (Pro Metronome- Tempo, Beat; by Xiao Yixiang). They then ran two to three times a week for two weeks up to 30 minutes per session with the metronome set at the new cadence. After two weeks, repeat testing using the same protocol was completed. A Mann-Whitney U test analyzed differences between groups.

Results

Cadence at one minute (p = 0.037) and average cadence over the entire run (p=0.002) increased in the intervention group only with a large effect size (Cohens d = 0.837). No other group differences were found.

Conclusion

A pragmatic gait retraining protocol with metronome augmentation including one instructional and four to six independent sessions over a two-week duration increased cadence without negative effects on HR, RPE, distance. Biomechanics did not change with this intervention. Further research with pragmatic gait retraining protocols that increase cadence are needed with larger sample sizes, repeated measures over time, across runners of various abilities and experience levels.

Level of Evidence

Level 2.

Effects of a 12-week gait retraining program on the Achilles tendon adaptation of habitually shod runners

PURPOSE

This study investigated the effects of a 12-week gait retraining program on the morphological and mechanical properties of the Achilles tendon (AT) during running on the basis of real-time dynamic ultrasound imaging.

METHODS

A total of 30 male recreational runners who were used to wearing cushioned shoes with a rearfoot strike (RFS) pattern were recruited. They were randomized into a retraining group (RG, n = 15) and a control group (CG, n = 15). The RG group was asked to run in five-fingered minimalist shoes with a forefoot strike (FFS) pattern, and the CG group was asked to keep their strike pattern. Three training sessions were performed per week. All the participants in RG uploaded running tracks obtained through a mobile application (.jpg) after each session for training supervision. The ground reaction force, kinematics, and kinetics of the ankle joint at 10 km/h were collected using an instrumented split-belt treadmill and a motion capture system. The morphological (length and cross-sectional area) and mechanical characteristics (force, stress, strain, etc.) of AT in vivo were recorded and calculated with a synchronous ultrasonic imaging instrument before and after the intervention. Repeated two-way ANOVA was used to compare the aforementioned parameters.

RESULTS

A total of 28 participants completed the training. The strike angle of RG after training was significantly smaller than that before training and significantly smaller than that of CG after training (F (1, 13)  = 23.068, p < 0.001, partial η2  = 0.640). The length (F (1, 13)  = 10.086, p = 0.007, partial η2  = 0.437) and CSA (F (1, 13)  = 7.475, p = 0.017, partial η2  = 0.365) of AT in RG increased after training. A significant main effect for time was observed for the time-to-peak AT force (F (1, 13)  = 5.225, p = 0.040, partial η2  = 0.287), average (F (1, 13)  = 7.228, p = 0.019, partial η2  = 0.357), and peak AT loading rate (F (1, 13)  = 11.687, p = 0.005, partial η2  = 0.473).

CONCLUSION

Preliminary evidence indicated that a 12-week gait retraining program could exert a beneficial effect on AT. 57% (8/14) runners in RG shifted from RFS to FFS pattern. Although not all runners were categorized as FFS pattern after the intervention, their foot strike angle was reduced. Retraining primarily positively promoted AT morphological properties (i.e., CSA and length) to strengthen AT capability for mechanical loading.

Relevant Biomechanical Variables in Skateboarding: A Literature Review

Skateboarding, once regarded primarily as a means of transportation and entertainment for youth, has become a recognized professional sport, gaining global popularity. With its recent inclusion in the Olympics, a growing imperative exists to comprehensively understand biomechanics explaining skateboarding performance. This literature review seeks to consolidate knowledge within this domain, focusing on experimental and modeling studies about skateboard riding and tricks. The criteria for study selection encompassed content relevance and publication year, spanning from the last two decades and extending further back to 1980 following cross-referencing of seminal works. Peer-reviewed journal articles, conference proceedings, and books were considered, with comprehensive searches conducted on electronic databases, including SCOPUS, PubMed, Scielo, and Taylor & Francis. Comprehending the biomechanical facets of skateboarding is essential in promoting its use and ensuring safety among all practitioners. Insights into factors such as body kinetics, kinematics, and muscle activation represent a foundational step toward understanding the nuances of this sport with implications for both clinical and biomechanical research. Modern data collection systems such as inertial measurement units (IMU) and electromyography (EMG) offer unprecedented insights into human performance during skateboarding, such as joint range of motion, coordination, and muscle activation, whether in casual riding or executing complex tricks and maneuvers. Developing robust modeling approaches also holds promise for enhancing skateboarding training and performance. Crucially, these models can serve as the initial framework for understanding injury mechanisms and implementing strategies to improve performance and mitigate injury risks.

Preinjury Knee and Ankle Mechanics during Running Are Reduced among Collegiate Runners Who Develop Achilles Tendinopathy

INTRODUCTION

Achilles tendinopathies (AT) are common in runners, but prospective data assessing running mechanics associated with developing AT are limited. Asymmetry in running mechanics is also considered a risk factor for injury, although it is unknown if the problematic mechanics occur on the injured limb only or are present bilaterally.

PURPOSE

This study aimed to prospectively identify differences in preinjury running biomechanics in collegiate runners who did and did not develop AT and determine if between-limb asymmetries were associated with which limb developed AT.

METHODS

Running gait data were obtained preseason on healthy collegiate cross-country runners, and AT incidence was prospectively recorded each year. Spatiotemporal, ground reaction forces, and joint kinematics and kinetics were analyzed. Linear mixed-effects models assessed differences in biomechanics between those who did and did not develop AT during the subsequent year. Generalized linear mixed-effects models determined if the asymmetry direction was associated with which limb developed an AT, with odds ratios (OR) and 95% confidence intervals (95% CI) reported.

RESULTS

Data from 106 runners were analyzed and 15 developed AT. Preinjury biomechanics of runners who developed AT showed less peak knee flexion (noninjured: 45.9° (45.2°-46.6°), injured: 43.2° (41.5°-44.9°), P < 0.001), ankle dorsiflexion (noninjured: 28.7° (28.0°-30.2°), injured: 26.0° (23.8°-28.3°), P = 0.01), and knee extensor moment (noninjured: -2.18 (N·m)·kg -1 (-2.24 to -2.12 (N·m)·kg -1 ), injured: -2.00 (N·m)·kg -1 (-2.17 to -1.84 (N·m)·kg -1 ), P = 0.02). The limb demonstrating less peak knee flexion had greater odds of sustaining an AT (OR, 1.29 (1.00-1.65), P = 0.05).

CONCLUSIONS

Knee and ankle kinematics, in addition to knee kinetics, were associated with developing an AT. Monitoring these mechanics may be useful for prospectively identifying runners at risk of developing AT.

Pre-pubertal runners demonstrate greater variability in running kinematics than post-pubertal runners

BACKGROUND

Adolescents undergo a period of motor incoordination during puberty characterized by high movement variability. It is unknown if differences in running kinematics variability exist among adolescent long-distance runners.

RESEARCH QUESTION

Is kinematic variability different among male and female adolescent long-distance runners of different stages of physical maturation?

METHODS

We enrolled 114 adolescent long-distance runners (ages 8-19, F = 55, M = 59) in this secondary analysis of a larger cross-sectional study. Participants completed a three-dimensional overground running analysis at a comfortable self-selected speed. Peak frontal, sagittal, and transverse plane hip, knee, and ankle/shoe joint angles from the right leg were identified during stance phase for at least five trials. Variability in running kinematics was quantified as the standard deviation of the peak joint angles among the running trials for each participant. Participants were stratified by sex and stage of physical maturation (pre-, mid-, post-pubertal) and two-way ANOVAs compared between-subjects variability among groups (p ≤ .05).

RESULTS

Significant sex by maturation interactions were observed for hip external rotation and ankle external rotation variability. Sex differences were observed for hip internal rotation, with males demonstrating greater variability, and ankle internal rotation, with females demonstrating greater variability. Pre-pubertal runners demonstrated significantly greater variability than mid-pubertal runners for hip flexion, and greater variability than post-pubertal runners for hip flexion, hip adduction, hip internal rotation, and knee flexion.

SIGNIFICANCE

Pre-pubertal adolescent long-distance runners demonstrate greater stance phase variability in running kinematics than post-pubertal adolescent long-distance runners, while adolescent males and females demonstrate similar variability. Anthropometric and neuromuscular changes that occur during puberty likely influence running patterns and may contribute to more consistent kinematic patterns for post-pubertal runners.

Acute effect of foot strike patterns on in vivo tibiotalar and subtalar joint kinematics during barefoot running

BACKGROUND

Foot kinematics, such as excessive eversion and malalignment of the hindfoot, are believed to be associated with running-related injuries. The majority of studies to date show that different foot strike patterns influence these specific foot and ankle kinematics. However, technical deficiencies in traditional motion capture approaches limit knowledge of in vivo joint kinematics with respect to rearfoot and forefoot strike patterns (RFS and FFS, respectively). This study uses a high-speed dual fluoroscopic imaging system (DFIS) to determine the effects of different foot strike patterns on 3D in vivo tibiotalar and subtalar joints kinematics.

METHODS

Fifteen healthy male recreational runners underwent foot computed tomography scanning for the construction of 3-dimensional models. A high-speed DFIS (100 Hz) was used to collect 6 degrees of freedom kinematics for participants' tibiotalar and subtalar joints when they adopted RFS and FFS in barefoot condition.

RESULTS

Compared with RFS, FFS exhibited greater internal rotation at 0%-20% of the stance phase in the tibiotalar joint. The peak internal rotation angle of the tibiotalar joint under FFS was greater than under RFS (p < 0.001, Cohen's d = 0.92). RFS showed more dorsiflexion at 0%-20% of the stance phase in the tibiotalar joint than FFS. RFS also presented a larger anterior translation (p < 0.001, Cohen's d = 1.28) in the subtalar joint at initial contact than FFS.

CONCLUSION

Running with acute barefoot FFS increases the internal rotation of the tibiotalar joint in the early stance. The use of high-speed DFIS to quantify the movement of the tibiotalar and subtalar joint was critical to revealing the effects of RFS and FFS during running.

Predicting Tissue Loads in Running from Inertial Measurement Units

BACKGROUND

Runners have high incidence of repetitive load injuries, and habitual runners often use smartwatches with embedded IMU sensors to track their performance and training. If accelerometer information from such IMUs can provide information about individual tissue loads, then running watches may be used to prevent injuries.

METHODS

We investigate a combined physics-based simulation and data-based method. A total of 285 running trials from 76 real runners are subjected to physics-based simulation to recover forces in the Achilles tendon and patella ligament, and the collected data are used to train and test a data-based model using elastic net and gradient boosting methods.

RESULTS

Correlations of up to 0.95 and 0.71 for the patella ligament and Achilles tendon forces, respectively, are obtained, but no single best predictive algorithm can be identified.

CONCLUSIONS

Prediction of tissues loads based on body-mounted IMUs appears promising but requires further investigation before deployment as a general option for users of running watches to reduce running-related injuries.

KeepRunning: A MoCap-Based Rapid Test to Prevent Musculoskeletal Running Injuries

The worldwide popularisation of running as a sport and recreational practice has led to a high rate of musculoskeletal injuries, usually caused by a lack of knowledge about the most suitable running technique for each runner. This running technique is determined by a runner's anthropometric body characteristics, dexterity and skill. Therefore, this study aims to develop a motion capture-based running analysis test on a treadmill called KeepRunning to obtain running patterns rapidly, which will aid coaches and clinicians in assessing changes in running technique considering changes in the study variables. Therefore, a review and proposal of the most representative events and variables of analysis in running was conducted to develop the KeepRunning test. Likewise, the minimal detectable change (MDC) in these variables was obtained using test-retest reliability to demonstrate the reproducibility and viability of the test, as well as the use of MDC as a threshold for future assessments. The test-retest consisted of 32 healthy volunteer athletes with a running training routine of at least 15 km per week repeating the test twice. In each test, clusters of markers were placed on the runners' body segments using elastic bands and the volunteers' movements were captured while running on a treadmill. In this study, reproducibility was defined by the intraclass correlation coefficient (ICC) and MDC, obtaining a mean value of ICC = 0.94 ± 0.05 for all variables and MDC = 2.73 ± 1.16° for the angular kinematic variables. The results obtained in the test-retest reveal that the reproducibility of the test was similar or better than that found in the literature. KeepRunning is a running analysis test that provides data from the involved body segments rapidly and easily interpretable. This data allows clinicians and coaches to objectively provide indications for runners to improve their running technique and avoid possible injury. The proposed test can be used in the future with inertial motion capture and other wearable technologies.

Biomechanics and Injury Prevention for Barefoot/Minimalist Running

» Biomechanical studies indicate that barefoot/minimalist running coincides with a transition to an anterior foot strike, lower vertical loading rates, higher cadences, less energy absorption at the knee joint, and higher energy absorption at the ankle joint.» The clinical outcome studies indicate improvement of previous injuries and equivocal injury rates in the barefoot/minimal-style running groups.» Foot strike pattern is more important than footwear regarding injury prevention and vertical loading rate.» Minimalist footwear places higher degrees of stress on the ankle joints and an increased injury rate when abruptly transitioning to barefoot running. Runners must weigh the risks and benefits and take caution to properly strengthen their feet and safely transition to minimalist running.

Reliability of 2D video analysis assessing running kinematic variables in patients with exercise-related leg pain in a primary care practice

BACKGROUND

Suboptimal lower limb and trunk positionings is known to influence exercise-related leg pain (ERLP). It is unknown whether simple 2D video analysis is useful for recording and interpreting running variables in a primary care practice.

RESEARCH QUESTION

Is 2D video analysis a reliable instrument to assess running variables in patients with ERLP in a primary care practice?

METHODS

Participants undergoing an evaluation for ERLP in two primary care practices were studied. In this reliability study, analysis of running variables was performed by 4 blinded raters on one-stride videos captured with non-high speed cameras (30 fps). Intraclass correlation coefficients (two-way random; ICC 2,1) were calculated to determine the inter-rater reliability. The intra-rater reliability was presented by ICC type two-way mixed (3,1). Footstrike pattern was analyzed by calculating the Fleiss' kappa for inter-rater agreement and Cohen's kappa for intra-rater agreement. Sample size calculation indicated that 16 participants would be required for answering the research question.

RESULTS

Data of all 16 participants (9 males, age 31 ± 10 yr) were of sufficient quality for analysis. The 2D video analysis demonstrated excellent inter-rater reliability with an overall ICC value of 0.999 (95 % CI = 0.998-0.999). The ICC value of the eversion was 0.384 (95 % CI = 0.148-0.66) and after correction of the systematic error, 0.817 (95 % CI = 0.664-0.922). The agreement on footstrike was substantial with a Fleiss kappa of 0.737. The overall intra-rater reliability was excellent with an ICC value of 0.997 (95 % CI = 0.996-0.997). The intra-rater agreement of the footstrike was excellent with a Cohen's kappa of 0.868.

SIGNIFICANCE

2D video analysis provides a highly reliable, relative inexpensive, feasible and suitable measuring instrument for determining running variables in patients ERLP in a primary care setting. This simple technique may identify possible running variables associated with different types of ERLP and may serve as an instrument for tailor-made gait retraining programs.

Mechanics of The Medial Gastrocnemius-Tendon Unit in Behaving more Efficiently in Habitual Non-Rearfoot Strikers than in Rearfoot Strikers during Running

This study aims to quantify how habitual foot strike patterns would affect ankle kinetics and the behavior and mechanics of the medial gastrocnemius-tendon unit (MTU) during running. A total of 14 runners with non-rearfoot strike patterns (NRFS) and 15 runners with rearfoot strike patterns (RFS) ran on an instrumented treadmill at a speed of 9 km/h. An ultrasound system and a motion capture system were synchronously triggered to collect the ultrasound images of the medial gastrocnemius (MG) and marker positions along with ground reaction forces (GRF) during running. Ankle kinetics (moment and power) and MG/MTU behavior and mechanical properties (MG shortening length, velocity, force, power, MTU shortening/lengthening length, velocity, and power) were calculated. Independent t-tests were performed to compare the two groups of runners. Pearson correlation was conducted to detect the relationship between foot strike angle and the MTU behavior and mechanics. Compared with RFS runners, NRFS runners had 1) lower foot strike angles and greater peak ankle moments; 2) lower shortening/change length and contraction velocity and greater MG peak force; 3) greater MTU lengthening, MTU shortening length and MTU lengthening velocity and power; 4) the foot strike angle was positively related to the change of fascicle length, fascicle contraction length, and MTU shortening length during the stance phase. The foot strike angle was negatively related to the MG force and MTU lengthening power. The MG in NRFS runners appears to contract with greater force in relatively isometric behavior and at a slower shortening velocity. Moreover, the lengthening length, the lengthening velocity of MTU, and the MG force were greater in habitual NRFS runners, leading to a stronger stretch reflex response potentially.

Increasing Step Frequency Reduces Patellofemoral Joint Stress and Patellar Tendon Force Impulse More at Low Running Speed

PURPOSE

Patellofemoral pain syndrome and patellar tendinopathy are important running-related overuse injuries. This study investigated the interaction of running speed and step frequency alterations on peak and cumulative patellofemoral joint stress (PFJS) and patellar tendon force (PTF) parameters.

METHODS

Twelve healthy individuals completed an incremental running speed protocol on a treadmill at habitual, increased and decreased step frequency. Peak PFJS and PTF, peak rate of PFJS and PTF development, and PFJS and PTF impulse per kilometer (km) were calculated using musculoskeletal modeling.

RESULTS

With increasing running speed, peak PFJS ( P < 0.001) and PTF ( P < 0.001) and peak rate of PFJS ( P < 0.001) and PTF ( P < 0.001) development increased, whereas PFJS ( P < 0.001) and PTF ( P < 0.001) impulse per km decreased. While increasing step frequency by 10%, the peak PFJS ( P < 0.001) and PTF ( P < 0.001) and the PFJS ( P < 0.001) and PTF ( P < 0.001) impulse per kilometer decreased. No significant effect of step frequency alteration was found for the peak rate of PFJS ( P = 0.008) and PTF ( P = 0.213) development. A significant interaction effect was found for PFJS ( P < 0.001) and PTF ( P < 0.001) impulse per km, suggesting that step frequency alteration was more effective at low running speed.

CONCLUSIONS

The effectiveness of step frequency alteration on PFJS and PTF impulse per km is dependent on the running speed. With regard to peak PFJS and PTF, step frequency alteration is equally effective at low and high running speeds. Step frequency alteration was not effective for peak rate of PFJS and PTF development. These findings can assist the optimization of patellofemoral joint and patellar tendon load management strategies.

The effects of alteration in muscle activation on the iliotibial band during an exhaustive run

PURPOSE

Long exhausted running causes pain at the lateral femoral epicondyle for some runners. The pain has been revealed to be related to the behavior of the iliotibial band (ITB) during running. The purpose of this study is to examine the effects of in-series musculature on the behavior of the ITB in healthy participants during an exhaustive run.

METHODS

Twenty-five healthy participants (15 males, 10 females) were recruited in the current study. All participants performed a 30-minute exhaustive run at a self-selected speed with laboratory-provided footwear. Muscle activities of ITB-related muscles including tensor fascia latae (TFL), gluteus maximus (Gmax), gluteus medius (Gmed), biceps femoris (BF), and vastus lateralis (VL) were recorded using surface electromyography (EMG).

RESULTS

Maximum amplitudes at the initial stage (the first minute), the mid stage (the 15-minute), and the end stage (the 30-minute) were compared during the exhaustive running. Significant decreases (p < 0.05) were observed in the maximum amplitudes of the TFL, Gmax, Gmed, and BF at the mid (decreased by ~ 15%) and end (decreased by ~ 30%) stages compared to the initial stage. The onset and the offset remained unaltered during the running (p ≥ 0.05).

CONCLUSION

The behavior of the healthy ITB might be altered due to the activities of the in-series musculature. Excessive compression forces might be applied to the lateral femoral epicondyle from the ITB to provide stability for the knee joint during an exhaustive run. The findings could provide a basic understanding of the behavior of healthy ITB.

Exercise behavior, practice, injury, and symptoms of respiratory tract infection of 502 Brazilian adults during lockdown oscillations in two years (2021-2022) of the COVID-19 pandemic

BACKGROUND

In the period between 2020 and 2023, during the COVID-19 (coronavirus disease 2019) pandemic, many countries released their restriction measures so that individuals were able to begin practicing physical exercises and outdoor sports again. The purpose of the current study was to evaluate the physical exercise behavior, symptoms of respiratory tract infection, and training practice, as well as aspects of pain and injuries in the lower limbs of adults during periods of lockdown oscillations in the two years of the COVID-19 pandemic in Brazil.

METHODS

Cross-sectional study.

PARTICIPANTS

A total of 502 adults were evaluated during two consecutive years of the COVID-19 pandemic, corresponding to the years 2021 and 2022. A virtual questionnaire was applied using the Google Forms platform through a link, or a Quick Response Code available in social media environments. The variables collected were: anthropometric characteristics, presence of comorbidities, clinical history for the diagnosis of COVID-19, and behavior related to physical exercise practices, divided into five topics: (1) physical exercise habits; (2) symptoms and health care utilization; (3) habit of practicing physical exercise in relation to the prevention of COVID-19; (4) preventive measures for COVID-19; and (5) feelings and reasons for practicing exercises.

RESULTS

A total 79.0% of the participants returned to the practice of physical exercise after a period of social isolation due to COVID-19, with running (30.0%) and muscle strength training (50.0%) being the most prevalent modalities, in which 62.0% of practitioners carried out the activity individually, without any professional or technical monitoring. With regard to physical preparation, 61.0% reported performing pre-training stretching, 64.0% associated with muscular resistance training. Of these, 89% did not report current injuries or pain symptoms when returning to exercise (69.0%). Total of 60.5% reported experiencing respiratory tract symptoms of COVID-19 and seeking a consultation with a doctor, and 61.0% performed diagnostic test, with RT-PCR (Real time-polymerase chain reaction) being the most common test. Of those tested, 55.0% were positive for COVID-19, without the need for hospitalization (95.0%). The most commonly used measures for the prevention of COVID-19 were the fabric or surgical mask. The predominant feeling in the pandemic was anxiety (50.5%) and the reasons for practicing sports were: physical conditioning (30.9%), a feeling of pleasure (21.3%), and weight loss (20.3%).

CONCLUSION

After two years of the COVID-19 pandemic (2021-2022), with periods of lockdown, there were low reports of injuries and pain symptoms after exercising on the return to physical exercise practices of running and strength training. However, the restrictions negatively affected the exercise behavior due to respiratory tract symptoms of COVID-19 and a reduction in training intensity, performed without any professional or technical supervision. The participants reported the use of a fabric or surgical mask for the prevention of COVID-19, and an increased feeling of anxiety. The reasons given for practicing physical exercise were physical conditioning, a feeling of pleasure, and weight loss.

The "impacts cause injury" hypothesis: Running in circles or making new strides?

Some of the earliest biomechanics research focused on running and the ground reaction forces generated with each step. Research in running gait accelerated in the 1970's as the growing popularity in running increased attention to the musculoskeletal injuries sustained by runners. Despite decades of high-quality research, running remains the most common cause of exercise-related musculoskeletal injuries and rates of overuse running-related injuries (RRI) have not appreciably declined since the research began. One leading area of running gait research focuses on discrete variables derived from the vertical ground reaction force, such as the vertical loading rate. Across sub-disciplines of running gait research, vertical loading rate is often discussed as the primary and undisputed variable associated with RRI despite only low to moderate evidence that retrospectively or prospectively injured runners generate greater vertical loading rates than uninjured counterparts. The central thesis of this review is that relying on vertical loading rate is insufficient to establish causal mechanisms for RRI etiology. To present this argument, this review examines the history of the 'impacts cause injury' hypothesis, including a historical look at ground reaction forces in human running and the research from which this hypothesis was generated. Additionally, a synthesis of studies that have tested the hypothesis is provided and recommendations for future research are discussed. Although it is premature to reject or support the 'impacts cause injury' hypothesis, new knowledge of biomechanical risk factors for RRI will remain concealed until research departs from the current path or adopts new approaches to previous paradigms.

Aetiological Factors of Running-Related Injuries: A 12 Month Prospective "Running Injury Surveillance Centre" (RISC) Study

BACKGROUND

Running-related injuries (RRIs) are a prevalent issue for runners, with several factors proposed to be causative. The majority of studies to date are limited by retrospective study design, small sample sizes and seem to focus on individual risk factors in isolation. This study aims to investigate the multifactorial contribution of risk factors to prospective RRIs.

METHODS

Recreational runners (n = 258) participated in the study, where injury history and training practices, impact acceleration, and running kinematics were assessed at a baseline testing session. Prospective injuries were tracked for one year. Univariate and multivariate Cox regression was performed in the analysis.

RESULTS

A total of 51% of runners sustained a prospective injury, with the calf most commonly affected. Univariate analysis found previous history of injury < 1 year ago, training for a marathon, frequent changing of shoes (every 0-3 months), and running technique (non-rearfoot strike pattern, less knee valgus, greater knee rotation) to be significantly associated with injury. The multivariate analysis revealed previous injury, training for a marathon, less knee valgus, and greater thorax drop to the contralateral side to be risk factors for injury.

CONCLUSION

This study found several factors to be potentially causative of injury. With the omission of previous injury history, the risk factors (footwear, marathon training and running kinematics) identified in this study may be easily modifiable, and therefore could inform injury prevention strategies. This is the first study to find foot strike pattern and trunk kinematics to relate to prospective injury.

Does orthotics use improve comfort, speed, and injury rate during running? A randomised control trial

BACKGROUND

Running is a hugely popular sport. Unfortunately, running-related injury (RRI) rates are high, particularly amongst amateur and recreational runners. Finding ways to reduce RRI rates and maximise comfort and performance for runners is important. Evidence regarding whether orthotics can successfully improve these parameters is limited and contradicting. Further research is required to provide runners with clearer guidance on the usefulness of orthotics.

AIM

To investigate the effect of Aetrex Orthotics on comfort, speed and RRI rates during recreational running.

METHODS

One hundred and six recreational runners were recruited on a voluntary basis via running clubs and social media pages and randomised into either the intervention or control group. Participants in the intervention group ran with Aetrex L700 Speed Orthotics inserted in their usual running shoes, whilst participants in the control group ran in their usual running shoes with no orthotics. The study ran for an 8-wk period. Participants provided data relating to running comfort, distance, and time during weeks 3-6. Participants provided data relating to any RRIs they sustained during all 8 wks. Running distance and time were used to calculate running speed in miles per hour (mph). For each outcome variable, 95% confidence intervals and P values were calculated to assess the statistical significance between the groups. For comfort and speed data, univariate multi-level analysis was performed, and for outcome variables with significant between group differences, multi-level multivariate analysis was performed to evaluate any confounding effects of gender and age.

RESULTS

Ninety-four participants were included in the final analysis (drop-out rate = 11%). Comfort and speed from 940 runs and 978 injury data reports were analysed. Participants who ran with orthotics reported, on average, speeds 0.30 mph faster (P = 0.20) and comfort scores 1.27 points higher (P ≤ 0.001) than participants who ran with no orthotics. They were also 2.22 times less likely to sustain an injury (P = 0.08) than participants who ran with no orthotics. However, findings were only significant for comfort and not for speed or injury rates. Age and gender were found to be significant predictors of comfort. However, the improvements in comfort reported by participants who ran with orthotics were still significant after adjusting for age and gender.

CONCLUSION

This study found orthotics to improve comfort and speed and prevent RRIs whilst running. However, these findings were only statistically significant for comfort.