Kinematics of recreational male runners in "super", minimalist and habitual shoes.

We conducted an exploratory analysis to compare running kinematics of 16 male recreational runners wearing Nike Vaporfly 4% (VP4), Saucony Endorphin racing flat (FLAT), and their habitual (OWN) footwear. We also explored potential relationships between kinematic and physiological changes. Runners (age: 33 ± 12 y, V˙ O2peak: 55.2 ± 4.3 ml · kg-1·min-1) attended 3 sessions after completing an V˙ O2peak test in which sagittal plane 3D kinematics at submaximal running speeds (60%, 70% and 80% ʋ V˙ O2peak) were collected alongside economy measures. Kinematics were compared using notched boxplots, and between-shoe kinematic differences were plotted against between-shoe economy differences. Across intensities, VP4 involved longer flight times (6.7 to 10.0 ms) and lower stance hip range of motion (~3°), and greater vertical pelvis displacement than FLAT (~0.4 cm). Peak dorsiflexion angles (~2°), ankle range of motion (1.0° to 3.9°), and plantarflexion velocities (11.3 to 89.0 deg · sec-1) were greatest in FLAT and lowest in VP4. Foot-ground angles were smaller in FLAT (2.5° to 3.6°). Select kinematic variables were moderately related to economy, with higher step frequencies and shorter step lengths in VP4 and FLAT associated with improved economy versus OWN. Footwear changes from OWN altered running kinematics. The most pronounced differences were observed in ankle, spatiotemporal, and foot-ground angle variables.

Immediate Effects of Manipulating Footwear or Cadence on the Lower Limb Biomechanics of Female Masters Runners.

The objective of this study was to compare the immediate effects of modifications to footwear or cadence on lower limb biomechanics of female Masters runners. After analyzing habitual treadmill running biomechanics in 20 female runners (52.4 [8.3] y), we assessed the effects of 5 conditions: (1) barefoot running, (2) Merrell Vapor Glove, (3) Merrell Bare Access, (4) Brooks Pure Flow, and (5) increasing cadence by 10%. In comparison with habitual biomechanics, greater vertical loading rates of the ground reaction force were observed during running barefoot or with a Merrell Vapor Glove or Bare Access. There was high variability among participants as to changes in foot kinematics during the conditions. Running barefoot (-26.0%) and with a Merrell Vapor Glove (-12.5%) reduced sagittal plane knee moments, but increased sagittal plane ankle moments (both 6.1%). Increasing cadence by 10% resulted in a more modest decrease in knee flexion moments (-7.7%) without increasing peak external ankle dorsiflexion moments. When asked if they would prefer minimalist shoes or increasing cadence, 11 participants (55%) chose cadence and 9 (45%) chose footwear. Minimalist footwear decreased sagittal knee moments, but increased vertical loading rate and sagittal ankle moments. Increasing cadence may be useful to lower sagittal knee moments without increasing ankle moments.

Validity and reliability of wearable inertial sensors in healthy adult walking: a systematic review and meta-analysis.

BACKGROUND: Inertial measurement units (IMUs) offer the ability to measure walking gait through a variety of biomechanical outcomes (e.g., spatiotemporal, kinematics, other). Although many studies have assessed their validity and reliability, there remains no quantitive summary of this vast body of literature. Therefore, we aimed to conduct a systematic review and meta-analysis to determine the i) concurrent validity and ii) test-retest reliability of IMUs for measuring biomechanical gait outcomes during level walking in healthy adults. METHODS: Five electronic databases were searched for journal articles assessing the validity or reliability of IMUs during healthy adult walking. Two reviewers screened titles, abstracts, and full texts for studies to be included, before two reviewers examined the methodological quality of all included studies. When sufficient data were present for a given biomechanical outcome, data were meta-analyzed on Pearson correlation coefficients (r) or intraclass correlation coefficients (ICC) for validity and reliability, respectively. Alternatively, qualitative summaries of outcomes were conducted on those that could not be meta-analyzed. RESULTS: A total of 82 articles, assessing the validity or reliability of over 100 outcomes, were included in this review. Seventeen biomechanical outcomes, primarily spatiotemporal parameters, were meta-analyzed. The validity and reliability of step and stride times were found to be excellent. Similarly, the validity and reliability of step and stride length, as well as swing and stance time, were found to be good to excellent. Alternatively, spatiotemporal parameter variability and symmetry displayed poor to moderate validity and reliability. IMUs were also found to display moderate reliability for the assessment of local dynamic stability during walking. The remaining biomechanical outcomes were qualitatively summarized to provide a variety of recommendations for future IMU research. CONCLUSIONS: The findings of this review demonstrate the excellent validity and reliability of IMUs for mean spatiotemporal parameters during walking, but caution the use of spatiotemporal variability and symmetry metrics without strict protocol. Further, this work tentatively supports the use of IMUs for joint angle measurement and other biomechanical outcomes such as stability, regularity, and segmental accelerations. Unfortunately, the strength of these recommendations are limited based on the lack of high-quality studies for each outcome, with underpowered and/or unjustified sample sizes (sample size median 12; range: 2-95) being the primary limitation.

Is combining gait retraining or an exercise programme with education better than education alone in treating runners with patellofemoral pain?A randomised clinical trial.

DESIGN: Single-blind randomised clinical trial. OBJECTIVE: To compare the effects of three 8-week rehabilitation programmes on symptoms and functional limitations of runners with patellofemoral pain (PFP). METHODS: Sixty-nine runners with PFP were randomly assigned to one of three intervention groups: (1) education on symptoms management and training modifications (education); (2) exercise programme in addition to education (exercises); (3) gait retraining in addition to education (gait retraining). Symptoms and functional limitations were assessed at baseline (T0), and after 4, 8 and 20 weeks (T4, T8 and T20) using the Knee Outcome Survey of the Activities of Daily Living Scale (KOS-ADLS) and visual analogue scales (VASs) for usual pain, worst pain and pain during running. Lower limb kinematics and kinetics during running, and isometric strength were also evaluated at T0 and T8. The effects of rehabilitation programmes were assessed using two-way analysis of variance. RESULTS: No significant group × time interactions (p<0.447) were found for KOS-ADLS and VASs. All three groups showed similar improvements at T4, T8 and T20 compared with T0 (p<0.05). Only the exercises group increased knee extension strength following rehabilitation (group × time: p<0.001) and only the gait retraining group (group × time: p<0.001) increased step rate (+7.0%) and decreased average vertical loading rate (-25.4%). CONCLUSION: Even though gait retraining and exercises improved their targeted mechanisms, their addition to education did not provide additional benefits on symptoms and functional limitations. Appropriate education on symptoms and management of training loads should be included as a primary component of treatment in runners with PFP. TRIAL REGISTRATION NUMBER: ClinicalTrials.gov (NCT02352909).

Effects of rehabilitation approaches for runners with patellofemoral pain: protocol of a randomised clinical trial addressing specific underlying mechanisms.

BACKGROUND: Patellofemoral pain (PFP) is highly prevalent in runners, and often leads to functional limitations and cessation of running. Training errors as well as decreased lower limb strength and control during running have all been associated with PFP. While strengthening and gait retraining are commonly used by clinicians, no randomised clinical trial has compared these modalities in runners with PFP. The primary objective of this randomised clinical trial will be to compare the effects of three rehabilitation programs targeting different key factors on symptoms and functional limitations of runners with PFP. The secondary objective will be to explore the factors leading to clinical improvement. METHODS/DESIGN: We will conduct a single-blind randomised clinical trial to compare three different 8 week rehabilitation programs: Group 1 will receive education on symptoms management based on training modifications; Group 2 will receive an exercise program targeting lower limb strengthening and control in addition to the education component of Group 1; Group 3 will receive running gait retraining advice as well as the education component of Group 1. Sixty-nine runners with PFP will be recruited and will be seen by independent physiotherapists on five visits through 8 weeks. The primary outcome measure will be symptoms and functional limitations measured by the Knee Outcome Survey - Activities of Daily Living Scale questionnaire at baseline, and at the four, eight and 20 weeks follow-up. Secondary outcomes will include pain level measured using visual analog scales, and running mileage. Lower limb kinematics and kinetics during running, and isometric strength will also be evaluated at baseline and 8 weeks follow-up. The effects of rehabilitation programs on measures of symptoms and functional limitations will be assessed using a 2-way ANOVA (Groups x Time). Regression analyses will be used to identify if changes in running mechanics or strength are determinants of clinical success. DISCUSSION: Studies with a high level of evidence are needed to determine the best rehabilitation interventions for runners with PFP. This randomised clinical trial will be the first to compare programs targeting different key factors linked with PFP. Results may guide clinicians and improve their clinical outcomes when treating runners with PFP. TRIAL REGISTRATION: ClinicalTrials.gov: NCT02352909. Registered on December 3, 2014.

The Effects of a Multimodal Rehabilitation Program on Symptoms and Ground-Reaction Forces in Runners With Patellofemoral Pain Syndrome.

CONTEXT: Patellofemoral pain (PFP) is one of the most frequent running-related injuries. However, few interventions taking into consideration the specificity of running have been shown to be effective in runners with PFP. OBJECTIVE: To evaluate the effects of a multimodal rehabilitation program including lower-limb-strengthening/ motor-control exercises, advice on running biomechanics, and symptoms management on symptoms, strength, and ground-reaction forces in runners with PFP. DESIGN: Pre- to post- quasi-experimental. SETTING: Gait-analysis laboratory and private physical therapy clinic. PARTICIPANTS: 21 runners with PFP (34.1 ± 6.0 y old, symptoms duration 38.1 ± 45.5 mo). INTERVENTION: An 8-wk multimodal rehabilitation program including lower-limb- and core-strengthening and motor-control exercises, as well as advice on running gait and symptoms management. MAIN OUTCOME MEASURES: The Activities of Daily Living Scale of the Knee Outcome Survey (KOS-ADLS) questionnaire and visual analog scales for usual pain (VAS-U), worst pain (VAS-W), and pain during running (VAS-R) were used to assess changes in symptoms and function. Vertical ground-reaction forces (VGRF) during running and lower-limb isometric strength were also measured. RESULTS: Statistically and clinically significant improvements (P < .001) were reported on KOS-ADLS (+17.8 pts), VAS-U (-19.2 pts), VAS-W (-28.7 pts), and VAS-R (-32.2 pts) after the intervention. No significant changes in isometric strength were observed. The instantaneous vertical loading rate was decreased after the intervention (P = .002), and this reduction was correlated with changes in KOS-ADLS scores (P = .028). CONCLUSION: This multimodal intervention was successful in reducing pain and improving function of runners with PFP. However, no significant changes in lower-limb strength were observed. It appears that changes in VGRF combined with appropriate training advice could explain the clinical outcomes.

Translation, cross-cultural adaptation and validation of the French version of the Knee Outcome Survey-Activities of Daily Living Scale.

PURPOSE: The Activities of Daily Living Scale of the Knee Outcome Survey (KOS-ADLS) is a joint-specific questionnaire measuring functional limitation experienced by individuals with knee disorders. The original English version of the KOS-ADLS has been shown to be highly reliable and responsive to change. The purpose of this study was to perform a translation and cross-cultural adaptation of the original version of the KOS-ADLS questionnaire into French and to validate this French version of the questionnaire. METHOD: In accordance with standard procedure, the original version of the KOS-ADLS was translated and cross-culturally adapted into French. Once the final French version of the KOS-ADLS was developed, it was subjected to further psychometric evaluation with 76 individuals with knee disorders. Each participant completed the KOS-ADLS on three occasions: at baseline, two days later to evaluate test-retest reliability, and four weeks later to evaluate responsiveness. Symptoms and function-oriented construct questions were also completed to evaluate construct-convergent and known-group validity. RESULTS: The cross-cultural adaptation procedure revealed no major problems with content or language. The French version of the KOS-ADLS showed excellent test-retest reliability with low measurement error (intraclass correlation coefficient = 0.92, minimal detectable change = 8.3), as well as high responsiveness (standardized response mean = 1.41; clinically important difference = 13.6). Further, it discriminates between different levels of self-rated or clinician-rated knee function. CONCLUSIONS: The French version of the KOS-ADLS is a reliable, valid and responsive questionnaire for the assessment of functional limitation in individuals with musculoskeletal knee disorders.

Return to Running after Knee Arthroplasty: A Case Report.

Individuals who have undergone knee arthroplasty may still want to run, but no study has reported a progression to guide patients and clinicians. The objective of this case report is to document the process of returning to running after total knee arthroplasty with a 1-year follow-up. The client was a 55-year-old woman, former triathlete, who underwent unilateral knee arthroplasty 1 year prior to consultation. She alternated slow running with walking and increased based on symptoms. She also performed a lower limb exercise programme. The client was a low-impact forefoot striker, ran with a high step rate and wore minimalist shoes. During the 1-year follow-up, she reported no knee pain but experienced minor episodes of calf strains. Towards the end, her comfort level was best when alternating running and walking for 3-4 km, three to four times per week. The client reached her objective of finishing an olympic distance triathlon. The exercise programme also helped to increase lower limb strength and improve physical performance. This case report suggests that it is possible to return to running up to 1 year after total knee arthroplasty. Future research should study bigger samples and monitor implant wear to provide better guidance to patients and physiotherapists.

Certains individus désirent reprendre la course à pied après une arthroplastie du genou. Cependant, aucune étude n'a exploré une progression sécuritaire. L'objectif de cette étude de cas est de documenter un retour à la course avec un suivi d'un an. La cliente était une femme triathlète de 55 ans, ayant subi une arthroplastie unilatérale du genou. Un an après sa chirurgie, elle a alterné la course à vitesse lente avec la marche et a progressé en fonction des symptômes, en plus d'effectuer un programme d'exercices. La cliente courait avec une attaque avant-pied, à faible impact, avec une cadence de pas élevée et portait des chaussures minimalistes. Pendant le suivi d'un an, elle n'a ressenti aucune douleur au genou mais a subi des blessures musculaires mineures aux mollets. Vers la fin du suivi, un régime hebdomadaire de 3-4 entraînements alternant course-marche pour 3­4 km était confortable. La cliente a atteint son objectif de compléter un triathlon de distance Olympique. Le programme de renforcement a permis d'augmenter la force du membre inférieur et d'améliorer les résultats aux tests fonctionnels. Cette étude de cas suggère qu'il est possible de retourner à la course après une arthroplastie du genou, jusqu'à un suivi d'un an.

Effects of two gait retraining programs on pain, function, and lower limb kinematics in runners with patellofemoral pain: A randomized controlled trial.

BACKGROUND: Patellofemoral Pain (PFP) is one of the main injuries in runners. Consistent evidence support strengthening programs to modulate symptoms, however, few studies investigated the effects of gait retraining programs. OBJECTIVE: To investigate the effects of two different two-week partially supervised gait retraining programs on pain, function, and lower limb kinematics of runners with PFP. METHODS: Randomized controlled trial. Thirty runners were allocated to gait retraining groups focusing on impact (n = 10) or cadence (n = 10), or to a control group (n = 10). Impact group received guidance to reduce tibial acceleration by 50%, while cadence group was asked to increase cadence by 7.5-10%. The control group did not receive any intervention. Usual and running pain, knee function, and lower limb kinematics (contralateral pelvic drop, hip adduction, knee flexion, ankle dorsiflexion, tibia inclination, and foot inclination) were evaluated before (T0), immediately after the intervention (T2), and six months after the protocol (T24). RESULTS: A significant group x time interaction was found for running pain (p = 0.010) and knee function (p = 0.019). Both programs had greater improvements in running pain compared to no intervention at T24 (Impact x Control-mean difference (MD) -3.2, 95% CI -5.1 to -1.3, p = 0.001; Cadence x Control-MD -2.9, 95% CI -4.8 to -1.0, p = 0.002). Participants of the impact group had greater improvements in knee function compared to no intervention at T2 (Impact x Control-MD 10.8, 95% CI 1.0 to 20.6, p = 0.027). No between-group differences in usual pain and lower limb kinematics were found (p>0.05). CONCLUSION: Compared to no intervention, both programs were more effective in improving running pain six months after the protocol. The program focused on impact was more effective in improving knee function immediately after the intervention. Clinical trial registry number: RBR-8yb47v.

Canadian Physiotherapists Integrate Virtual Care during the COVID-19 Pandemic.

Purpose: To examine Canadian physiotherapists' experiences in adapting their delivery of patient care during the COVID-19 pandemic. We examine the level of strain on the profession and barriers and enablers to virtual care and provide strategies to support future virtual care implementation. Methods: From May to October 2020, a series of eight cross-sectional survey cycles were distributed every 2-4 weeks through branches and divisions of the Canadian Physiotherapy Association, social media, and personal networks. Descriptive statistics summarized the main findings. Open ended questions were first analyzed inductively using thematic analysis, then deductively mapped to the Capability-Opportunity-Motivation Behavioural (COM-B) Model. Results: Between 1,820 (cycle 1) and 334 (cycle 7) physiotherapists responded. Median strain level was 5/5 (cycle 1) and dropped to median 3/5 (cycles 5-8). In cycle 1, 55% of physiotherapists had ceased in-person care, while 41% were providing modified in-person care. Of these physiotherapists, 79% were offering virtual care. As modified in-person care increased, virtual care continued as a substantial aspect of practice. Physiotherapists identified barriers (e.g., lack of hands-on care) and enabling factors (e.g., greater accessibility to patients) for virtual care. In-depth examination of the barriers and enablers through the COM-B lens identified potential interventions to support future virtual care implementation, including education and training resources for physiotherapists and communication and advocacy to patients and the public on the value of virtual care. Conclusions: Canadian physiotherapists exhibited high adaptability in response to COVID-19 through the rapid and widespread use of virtual care. By creating an in-depth understanding of the barriers and enablers to virtual care, along with potential interventions, this work will facilitate future opportunities to support and enhance physiotherapists' delivery of virtual care.

Objectif : examiner les expériences des physiothérapeutes canadiens qui ont adapté la prestation de leurs soins aux patients pendant la pandémie de COVID-19. Les auteurs ont examiné le degré de pression sur la profession de même que les obstacles et les incitations aux soins virtuels et ils proposent des stratégies pour appuyer la future mise en œuvre des soins virtuels. Méthodologie : de mai à octobre 2020, toutes les deux à quatre semaines, les auteurs ont distribué une série de huit cycles de sondages transversaux aux sections et divisions de l'Association canadienne de physiothérapie, aux réseaux sociaux et à leurs réseaux personnels. Ils ont utilisé des statistiques descriptives pour résumer leurs principales observations. Ils ont d'abord procédé à l'examen inductif des questions ouvertes par une analyse thématique, puis ont entrepris la cartographie déductive du modèle comportemental de capacité-possibilité-motivation (COM-B). Résultats : entre 1 820 (cycle 1) et 334 (cycle 7) physiothérapeutes ont répondu. Le degré médian de pression a atteint 5/5 (cycle 1), pour reculer à 3/5 (cycles 5 à 8). Au cours du cycle 1, 55 % des physiothérapeutes ont interrompu leurs soins en présentiel, tandis que 41 % ont fourni des soins modifiés en présentiel. Par ailleurs, 79 % de tous ces physiothérapeutes ont offert des soins virtuels. Alors que les soins modifiés en présentiel ont augmenté, les soins virtuels ont continué de représenter un volet substantiel de la pratique. Les physiothérapeutes ont relevé des obstacles (p. ex., absence de soins manuels) et des incitatifs (p. ex., plus grande accessibilité aux patients) aux soins virtuels. L'examen approfondi des obstacles et des incitatifs en fonction du modèle COM-B a permis d'extraire des interventions possibles pour appuyer la future mise en œuvre des soins virtuels, y compris des ressources d'éducation et de formation pour les physiothérapeutes et les communications et la promotion de la valeur des soins virtuels auprès des patients et du public. Conclusions : les physiothérapeutes canadiens ont fait preuve d'une grande adaptabilité en réponse à la COVID-19 grâce au recours rapide et généralisé aux soins virtuels. Par une compréhension approfondie des obstacles et des incitations aux soins virtuels et des interventions potentielles, la présente étude favorisera les futures occasions de soutenir et d'améliorer la prestation des soins virtuels par des physiothérapeutes.

The Role of Footwear, Foot Orthosis, and Training-Related Strategies in the Prevention of Bone Stress Injuries: A Systematic Review and Meta-Analysis.

Objective: To evaluate the effectiveness of footwear, foot orthoses and training-related strategies to prevent lower extremity bone stress injury (BSI). Design: Systematic review and meta-analysis. Data sources: Four bibliographic databases (from inception until November 2021): Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE and CINAHL. Eligibility criteria: Randomised controlled trials (RCTs) that assessed the risk of developing a BSI when using particular footwear, foot orthoses or training-related strategies such as muscle strengthening, stretching, and mechanical loading exercises. Results: Eleven studies were included in this systematic review. When wearing foot orthoses, the risk ratio of developing a BSI on any lower extremity bone is 0.47 (95% CI 0.26 to 0.87; p = 0.02). When doing pre-exercise dynamic stretching, the risk ratio of suffering a tibial BSI is 1.06 (95% CI 0.67 to 1.68; p = 0.79). No meta-analyses could be performed for footwear or training-related strategies. The quality of evidence for all these results is low considering the high risk of bias in each study, the low number of studies and the low number of cases in each study. Conclusion: This systematic review reveals the lack of high-quality studies in BSI prevention. Based on studies at high risk of bias, foot orthoses could potentially help prevent BSIs in the military setting. It is still unknown whether footwear and training-related strategies have any benefits. It is crucial to further investigate potential BSI prevention strategies in women and athletes. Research is also needed to assess the influence of running shoes and loading management on BSI incidence.

Running gait modifications can lead to immediate reductions in patellofemoral pain.

Gait modifications are commonly advocated to decrease knee forces and pain in runners with patellofemoral pain (PFP). However, it remains unknown if clinicians can expect immediate effects on symptoms. Our objectives were (1) to compare the immediate effects of gait modifications on pain and kinetics of runners with PFP; (2) to compare kinetic changes in responders and non-responders; and (3) to compare the effects between rearfoot strikers (RFS) and non-RFS. Sixty-eight runners with PFP (42 women, 26 men) ran normally on a treadmill before testing six modifications: 1- increase step rate by 10%; 2- 180 steps per minute; 3- decrease step rate by 10%; 4- forefoot striking; 5- heel striking; 6- running softer. Overall, there were more responders (pain decreased ≥1/10 compared with normal gait) during forefoot striking and increasing step rate by 10% (both 35%). Responders showed greater reductions in peak patellofemoral joint force than non-responders during all conditions except heel striking. When compared with non-RFS, RFS reduced peak patellofemoral joint force in a significant manner (P < 0.001) during forefoot striking (partial η 2 = 0.452) and running softer (partial η 2 = 0.302). Increasing step rate by 10% reduced peak patellofemoral joint force in both RFS and non-RFS. Forty-two percent of symptomatic runners reported immediate reductions in pain during ≥1 modification, and 28% had reduced pain during ≥3 modifications. Gait modifications leading to decreased patellofemoral joint forces may be associated with immediate pain reductions in runners with PFP. Other mechanisms may be involved, given that some runners reported decreased symptoms regardless of kinetic changes.

The Association Between Running Injuries and Training Parameters: A Systematic Review.

OBJECTIVE: To synthesize the current evidence on the incidence of running-related injuries (RRIs) and their association with training parameters (distance, duration, frequency, intensity), as well as recent changes in training parameters. DATA SOURCES: Searches were conducted in MEDLINE/Ovid, CINAHL, Embase, and SPORTDiscus from their inception through July 7, 2020. STUDY SELECTION: Included articles had to report prospective data on RRIs and training parameters or any changes in parameters and be published in English or French. Two reviewers independently screened the titles, abstracts, and full texts. DATA EXTRACTION: Two independent raters performed data extraction and quality assessment using QualSyst, a quality appraisal tool. DATA SYNTHESIS: A total of 36 articles that involved 23 047 runners were included. Overall, 6043 runners (26.2%) sustained an RRI (incidence range = 8.8%-91.3%). The incidence of RRI was 14.9% in novice runners (range = 9.4%-94.9%), 26.1% in recreational runners (range = 17.9%-79.3%), and 62.6% in competitive runners (range = 52.6%-91.3%). The 3 most frequently injured body parts were the knee (25.8%), foot/ankle (24.4%), and lower leg (24.4%). Overall, evidence about the association between weekly running distance, duration, frequency, intensity, or specific changes in training parameters and the onset of RRIs was conflicting. CONCLUSIONS: Despite high rates of RRIs, current evidence does not consistently link RRIs with specific training parameters or recent changes in training parameters. Therefore, caution should be taken when recommending optimal parameters or progressions. Given the multifactorial nature of RRIs, future studies also need to consider the interactions between training parameters as well as psychosocial, hormonal, lifestyle, and recovery outcomes to better understand the onset of RRIs.

The Influence of Running on Lower Limb Cartilage: A Systematic Review and Meta-analysis.

BACKGROUND: Running is a popular activity practiced worldwide. It is important to understand how running affects joint health to provide recommendations to sports medicine practitioners and runners. OBJECTIVE: Our aim was to summarize the influence of running on lower limb cartilage morphology and composition using quantitative magnetic resonance imaging (MRI). METHODS: Prospective repeated-measures studies evaluating cartilage using MRI before and after running were included. Data sources included Pubmed, Embase, CINAHL, SportDiscus, Web of Science, and Cochrane Central Registry of Controlled Trials. Qualitative analyses considered the number and methodological quality ratings of studies based on the QualSyst tool, and recommendations were based on the strength of evidence (strong, moderate, limited, or very limited). Quantitative analysis involved meta-analyses, for which effect sizes were calculated as Hedge's g standardized mean differences. RESULTS: We included 43 articles, assessing seven outcomes (lesions, volume, thickness, glycosaminoglycan content, and T1ρ, T2, and T2* relaxation times). Nineteen articles were rated as high quality, 24 were rated as moderate quality, and none were rated as low quality. Qualitative analyses suggest that running may cause an immediate reduction in knee cartilage volume, thickness, as well as T1ρ and T2 relaxation times immediately; however, these changes did not persist. Meta-analyses revealed a small and moderate decrease immediately following a single running bout in T2 relaxation time in the medial femur and tibia, respectively. Qualitative analyses indicated that the influence of repeated exposure to running on cartilage morphology and composition was limited. Despite conflicting evidence regarding pre-existing knee cartilage lesions, moderate evidence suggests that running does not lead to the formation of new lesions. Repeated running exposure did not cause changes to foot and ankle cartilage thickness or composition. CONCLUSIONS: Changes to lower limb cartilage following running are transient. Immediate changes to cartilage morphology and composition, which likely reflect natural fluid dynamics, do not persist and were generally not significant when pooled statistically. Results suggest that cartilage recovers well from a single running bout and adapts to repeated exposure. Given that moderate evidence indicates that running does not lead to new lesions, future trials should focus on clinical populations, such as those with osteoarthritis. TRIAL REGISTRATION: Not applicable.

Metabolic and performance responses of male runners wearing 3 types of footwear: Nike Vaporfly 4%, Saucony Endorphin racing flats, and their own shoes.

PURPOSE: We compared running economy (RE) and 3-km time-trial (TT) variables of runners wearing Nike Vaporfly 4% (VP4), Saucony Endorphin lightweight racing flats (FLAT), and their habitual running (OWN) footwear. METHODS: Eighteen male recreational runners (age = 33.5 ± 11.9 year (mean ± SD), peak oxygen uptake (VO2peak) = 55.8 ± 4.4 mL/kg·min) attended 4 sessions approximately 7 days apart. The first session consisted of a VO2peak test to inform subsequent RE speeds set at 60%, 70%, and 80% of the speed eliciting VO2peak. In subsequent sessions, treadmill RE and 3-km TTs were assessed in the 3 footwear conditions in a randomized, counterbalanced crossover design. RESULTS: Oxygen consumption (mL/kg·min) was less in VP4 (from 4.3% to 4.4%, p ≤ 0.002) and FLAT (from 2.7% to 3.4%, p ≤ 0.092) vs. OWN across intensities, with a non-significant difference between VP4 and FLAT (1.0%-1.7%, p ≥ 0.292). Findings related to energy cost (W/kg) and energetics cost of transport (J/kg·m) were comparable. VP4 3-km TT performance (11:07.6 ± 0:56.6 mm:ss) was enhanced vs. OWN by 16.6 s (2.4%, p = 0.005) and vs. FLAT by 13.0 s (1.8%, p = 0.032). The 3-km times between OWN and FLAT (0.5%, p = 0.747) were similar. Most runners (n = 11, 61%) ran their fastest TT in VP4. CONCLUSION: Overall, VP4 improved laboratory-based RE measures in male recreational runners at relative speeds compared to OWN, but the RE improvements in VP4 were not significant vs. FLAT. More runners exhibited better treadmill TT performances in VP4 (61%) vs. FLAT (22%) and OWN (17%). The variability in RE (-10.3% to 13.3%) and TT (-4.7% to 9.3%) improvements suggests that responses to different types of shoes are individualized and warrant further investigation.