Breast Cancer Disparity and Outcomes in Underserved Women.

Women in the United States who continue to face obstacles accessing health care are frequently termed an underserved population. Safety-net health care systems play a crucial role in mitigating health disparities and reducing burdens of disease, such as breast cancer, for underserved women. Disparities in health care are driven by various factors, including race and ethnicity, as well as socioeconomic factors that affect education, employment, housing, insurance status, and access to health care. Underserved women are more likely to be uninsured or underinsured throughout their lifetimes. Hence they have greater difficulty gaining access to breast cancer screening and are less likely to undergo supplemental imaging when needed. Therefore, underserved women often experience significant delays in the diagnosis and treatment of breast cancer, leading to higher mortality rates. Addressing disparities requires a multifaceted approach, with formal care coordination to help at-risk women navigate through screening, diagnosis, and treatment. Mobile mammography units and community outreach programs can be leveraged to increase community access and engagement, as well as improve health literacy with educational initiatives. Radiology-community partnerships, comprised of imaging practices partnered with local businesses, faith-based organizations, homeless shelters, and public service departments, are essential to establish culturally competent breast imaging care, with the goal of equitable access to early diagnosis and contemporary treatment. Published under a CC BY 4.0 license. Test Your Knowledge questions are available in the Online Learning Center. See the invited commentary by Leung in this issue.

Using artificial intelligence for exercise prescription in personalised health promotion: A critical evaluation of OpenAI's GPT-4 model.

The rise of artificial intelligence (AI) applications in healthcare provides new possibilities for personalized health management. AI-based fitness applications are becoming more common, facilitating the opportunity for individualised exercise prescription. However, the use of AI carries the risk of inadequate expert supervision, and the efficacy and validity of such applications have not been thoroughly investigated, particularly in the context of diverse health conditions. The aim of the study was to critically assess the efficacy of exercise prescriptions generated by OpenAI's Generative Pre-Trained Transformer 4 (GPT-4) model for five example patient profiles with diverse health conditions and fitness goals. Our focus was to assess the model's ability to generate exercise prescriptions based on a singular, initial interaction, akin to a typical user experience. The evaluation was conducted by leading experts in the field of exercise prescription. Five distinct scenarios were formulated, each representing a hypothetical individual with a specific health condition and fitness objective. Upon receiving details of each individual, the GPT-4 model was tasked with generating a 30-day exercise program. These AI-derived exercise programs were subsequently subjected to a thorough evaluation by experts in exercise prescription. The evaluation encompassed adherence to established principles of frequency, intensity, time, and exercise type; integration of perceived exertion levels; consideration for medication intake and the respective medical condition; and the extent of program individualization tailored to each hypothetical profile. The AI model could create general safety-conscious exercise programs for various scenarios. However, the AI-generated exercise prescriptions lacked precision in addressing individual health conditions and goals, often prioritizing excessive safety over the effectiveness of training. The AI-based approach aimed to ensure patient improvement through gradual increases in training load and intensity, but the model's potential to fine-tune its recommendations through ongoing interaction was not fully satisfying. AI technologies, in their current state, can serve as supplemental tools in exercise prescription, particularly in enhancing accessibility for individuals unable to access, often costly, professional advice. However, AI technologies are not yet recommended as a substitute for personalized, progressive, and health condition-specific prescriptions provided by healthcare and fitness professionals. Further research is needed to explore more interactive use of AI models and integration of real-time physiological feedback.

Surviving the COVID-19 pandemic: navigating the recovery of breast imaging services in a safety-net hospital.

PURPOSE: The purpose of this study was to determine the impact of COVID-19 on county safety-net breast imaging services and describe the steps taken to actively manage and mitigate delays. METHODS: This was an IRB exempt retrospective review of our county safety-net breast imaging practice analyzed for 4 distinct time periods: (1) "Shut-down period": March 17, 2020 to May 17, 2020; (2) "Phased re-opening": May 18, 2020 to June 30, 2020; (3) "Ramp-up": July 1, 2020 to September 30, 2020; and (4) "Current state": October 1, 2020 to September 30, 2021. These time periods were compared to identical time periods 1 year prior. For "Current state," given that the 1-year prior comparison encompassed the first 3 periods of the pandemic, the identical time period 2 years prior was also compared. RESULTS: Our safety-net practice sustained significant volume losses during the first 3 time periods with a 99% reduction in screening mammography in the shut-down period. Cancers diagnosed decreased by 17% in 2020 (n = 229) compared to 2019 (n = 276). By implementing multiple initiatives that targeted improved access to care, including building community-hospital partnerships and engagement through outreach events and a community education roadshow, we were able to recover and significantly exceed our pandemic screening volumes by 48.1% (27,279 vs 18,419) from October 1, 2020 to September 30, 2021 compared to the identical time period 1 year prior, and exceed our pre-pandemic screening volume by 17.4% (27,279 vs 23,234) compared to the identical time period 2 years prior. CONCLUSION: Through specific community outreach programs and optimized navigation, our safety-net breast imaging practice was able to mitigate the impact of COVID-19 on our patient population by increasing patient engagement and breast imaging services.

CEST-MRI for body oncologic imaging: are we there yet?

Chemical exchange saturation transfer (CEST) MRI has gained recognition as a valuable addition to the molecular imaging and quantitative biomarker arsenal, especially for characterization of brain tumors. There is also increasing interest in the use of CEST-MRI for applications beyond the brain. However, its translation to body oncology applications lags behind those in neuro-oncology. The slower migration of CEST-MRI to non-neurologic applications reflects the technical challenges inherent to imaging of the torso. In this review, we discuss the application of CEST-MRI to oncologic conditions of the breast and torso (i.e., body imaging), emphasizing the challenges and potential solutions to address them. While data are still limited, reported studies suggest that CEST signal is associated with important histology markers such as tumor grade, receptor status, and proliferation index, some of which are often associated with prognosis and response to therapy. However, further technical development is still needed to make CEST a reliable clinical application for body imaging and establish its role as a predictive and prognostic biomarker.

Optoacoustic Imaging With Decision Support for Differentiation of Benign and Malignant Breast Masses: A 15-Reader Retrospective Study.

BACKGROUND. Overlap in ultrasound features of benign and malignant breast masses yields high rates of false-positive interpretations and benign biopsy results. Optoacoustic imaging is an ultrasound-based functional imaging technique that can increase specificity. OBJECTIVE. The purpose of this study was to compare specificity at fixed sensitivity of ultrasound images alone and of fused ultrasound and optoacoustic images evaluated with machine learning-based decision support tool (DST) assistance. METHODS. This retrospective Reader-02 study included 480 patients (mean age, 49.9 years) with 480 breast masses (180 malignant, 300 benign) that had been classified as BI-RADS category 3-5 on the basis of conventional gray-scale ultrasound findings. The patients were selected by stratified random sampling from the earlier prospective 16-site Pioneer-01 study. For that study, masses were further evaluated by ultrasound alone followed by fused ultrasound and optoacoustic imaging between December 2012 and September 2015. For the current study, 15 readers independently reviewed the previously acquired images after training in optoacoustic imaging interpretation. Readers first assigned probability of malignancy (POM) on the basis of clinical history, mammographic findings, and conventional ultrasound findings. Readers then evaluated fused ultrasound and optoacoustic images, assigned scores for ultrasound and optoacoustic imaging features, and viewed a POM prediction score derived by a machine learning-based DST before issuing final POM. Individual and mean specificities at fixed sensitivity of 98% and partial AUC (pAUC) (95-100% sensitivity) were calculated. RESULTS. Averaged across all readers, specificity at fixed sensitivity of 98% was significantly higher for fused ultrasound and optoacoustic imaging with DST assistance than for ultrasound alone (47.2% vs 38.2%; p = .03). Across all readers, pAUC was higher (p < .001) for fused ultrasound and optoacoustic imaging with DST assistance (0.024 [95% CI, 0.023-0.026]) than for ultrasound alone (0.021 [95% CI, 0.019-0.022]). Better performance using fused ultrasound and optoacoustic imaging with DST assistance than using ultrasound alone was observed for 14 of 15 readers for specificity at fixed sensitivity and for 15 of 15 readers for pAUC. CONCLUSION. Fused ultrasound and optoacoustic imaging with DST assistance had significantly higher specificity at fixed sensitivity than did conventional ultrasound alone. CLINICAL IMPACT. Optoacoustic imaging, integrated with reader training and DST assistance, may help reduce the frequency of biopsy of benign breast masses.

Imaging and Management of Fibroepithelial Lesions of the Breast: Radiologic-Pathologic Correlation.

Fibroepithelial lesions (FELs) are among the most common breast masses encountered by breast radiologists and pathologists. They encompass a spectrum of benign and malignant lesions, including fibroadenomas (FAs) and phyllodes tumors (PTs). FAs are typically seen in young premenopausal women, with a peak incidence at 20-30 years of age, and have imaging features of oval circumscribed hypoechoic masses. Although some FA variants are especially sensitive to hormonal influences and can exhibit rapid growth (eg, juvenile FA and lactational adenomas), most simple FAs are slow growing and involute after menopause. PTs can be benign, borderline, or malignant and are more common in older women aged 40-50 years. PTs usually manifest as enlarging palpable masses and are associated with a larger size and sometimes with an irregular shape at imaging compared with FAs. Although FA and FA variants are typically managed conservatively unless large and symptomatic, PTs are surgically excised because of the risk of undersampling at percutaneous biopsy and the malignant potential of borderline and malignant PTs. As a result of the overlap in imaging and histologic appearances, FELs can present a diagnostic challenge for the radiologist and pathologist. Radiologists can facilitate accurate diagnosis by supplying adequate tissue sampling and including critical information for the pathologist at the time of biopsy. Understanding the spectrum of FELs can facilitate and guide appropriate radiologic-pathologic correlation and timely diagnosis and management of PTs. Published under a CC BY 4.0 license. Online supplemental material is available for this article. Quiz questions for this article are available through the Online Learning Center.

Diagnostic Evaluation of Recalled Noncalcified Lesions Using Ultrasound Alone Versus Ultrasound Plus Additional Mammographic Views: A Prospective Study.

BACKGROUND. The diagnostic performance of digital breast tomosynthesis (DBT) has been shown to be equal to that of diagnostic mammography. However, the value of additional mammographic views in diagnostic evaluations remains unclear. OBJECTIVE. The purpose of this study was to compare the performance of diagnostic breast ultrasound (US) alone with that of combined US and diagnostic mammography for specific noncalcified recalled abnormalities detected on screening DBT. METHODS. This was a prospective study with a single-arm management strategy. Women recalled for noncalcified lesions on screening DBT underwent initial diagnostic US as part of the study protocol. Additional diagnostic mammography was performed at the discretion of the radiologist. Imaging assessment decisions determined by BI-RADS assessments and management recommendations, biopsy outcomes, and follow-up were recorded using case report forms completed on the day of the diagnostic evaluation and stored in the electronic medical record. RESULTS. From July 10, 2017, to June 6, 2019, a total of 430 recalled noncalcified lesions in 399 women (mean age, 60 ± 12 [SD] years) were included. US alone was performed for 71.2% (306/430) of lesions, whereas US with diagnostic mammography was performed for 28.8% (124/430). Of the recalled lesions, 93.7% (178/190) of masses, 60.0% (51/85) of focal asymmetries, 46.1% (53/115) of asymmetries, 69.2% (9/13) of developing asymmetries, and 55.6% (15/27) of architectural distortions were evaluated with US alone. Of 93 lesions that underwent needle biopsy, 40.9% (38/93) were cancers, all of which were invasive. Thirty-five of 38 (92.1%) cancers were evaluated by US alone, whereas three (7.9%) were evaluated with US and diagnostic mammography. At a median follow-up of 25 months, six cancers were identified (three with US alone and three with US plus diagnostic mammography) in patients with initially benign workup. US alone had two false-negative cancers (one architectural distortion identified at follow-up and one mass biopsied stereotactically at initial detection). CONCLUSION. US alone is effective in the diagnostic evaluation of noncalcified masses recalled on screening tomosynthesis. For asymmetries, diagnostic mammography may be best without the need for additional US, whereas architectural distortions still warrant diagnostic mammography and US. CLINICAL IMPACT. Radiologists should consider performing US first for DBT-recalled noncalcified masses. Omitting diagnostic mammography when US is negative has a low false-negative rate.

Axillary Lymphadenopathy in the COVID-19 Era: What the Radiologist Needs to Know.

Axillary lymphadenopathy caused by the high immunogenicity of messenger RNA (mRNA) COVID-19 vaccines presents radiologists with new diagnostic dilemmas in differentiating vaccine-related benign reactive lymphadenopathy from that due to malignant causes. Understanding axillary anatomy and lymphatic drainage is key to radiologic evaluation of the axilla. US plays a critical role in evaluation and classification of axillary lymph nodes on the basis of their cortical and hilar morphology, which allows prediction of metastatic disease. Guidelines for evaluation and management of axillary lymphadenopathy continue to evolve as radiologists gain more experience with axillary lymphadenopathy related to COVID-19 vaccines. General guidelines recommend documenting vaccination dates and laterality and administering all vaccine doses contralateral to the site of primary malignancy whenever applicable. Guidelines also recommend against postponing imaging for urgent clinical indications or for treatment planning in patients with newly diagnosed breast cancer. Although conservative management approaches to axillary lymphadenopathy initially recommended universal short-interval imaging follow-up, updates to those approaches as well as risk-stratified approaches recommend interpreting lymphadenopathy in the context of both vaccination timing and the patient's overall risk of metastatic disease. Patients with active breast cancer in the pretreatment or peritreatment phase should be evaluated with standard imaging protocols regardless of vaccination status. Tissue sampling and multidisciplinary discussion remain useful in management of complex cases, including increasing lymphadenopathy at follow-up imaging, MRI evaluation of extent of disease, response to neoadjuvant treatment, and potentially confounding cases. An invited commentary by Weinstein is available online. ©RSNA, 2022.

Diagnosis, Management, and Percutaneous Sampling of Nipple-Areolar Calcifications: How Radiologists Can Help Patients Avoid the Operating Room.

OBJECTIVE: Both benign and malignant causes of calcifications in the nipple-areolar complex exist. BI-RADS terminology applies to the description and classification of nipple-areolar calcifications in the same way it does to calcifications elsewhere in the breast. Minimally invasive sampling can be performed safely and accurately with ultrasound-guided techniques, with a few technical modifications. CONCLUSION: This article provides insight regarding the management algorithm and image-guided interventional techniques for sampling nipple-areolar calcifications as an essential competency for breast imaging practices.

Sprint mechanical properties in soccer players according to playing standard, position, age and sex.

The purpose of this study was to quantify possible differences in sprint mechanical outputs in soccer according to soccer playing standard, position, age and sex. Sprint tests of 674 male and female players were analysed. Theoretical maximal velocity (v0), horizontal force (F0), horizontal power (Pmax), force-velocity slope (SFV), ratio of force (RFmax) and index of force application technique (DRF) were calculated from anthropometric and spatiotemporal data using an inverse dynamic approach applied to the centre-of-mass movement. Players of higher standard exhibited superior F0, v0, Pmax, RFmax and DRF scores (small to large effects) than those of lower standard. Forwards displayed clearly superior values for most outputs, ahead of defenders, midfielders and goalkeepers, respectively. Male >28 y players achieved poorer v0, Pmax and RFmax than <20, 20-24 and 24-28 y players (small to moderate), while female <20 y players showed poorer values than 20-24 and >24 y players for the same measures (small). The sex differences in sprint mechanical properties ranged from small to very large. These results provide a holistic picture of the force-velocity-power profile continuum in sprinting soccer players and serve as useful background information for practitioners when diagnosing individual players and prescribing training programmes.

Lifestyle changes in cancer patients undergoing curative or palliative chemotherapy: is it feasible?

INTRODUCTION: This study aimed to explore the feasibility of an individualized comprehensive lifestyle intervention in cancer patients undergoing curative or palliative chemotherapy. MATERIAL AND METHODS: At one cancer center, serving a population of 180,000, 100 consecutive of 161 eligible newly diagnosed cancer patients starting curative or palliative chemotherapy entered a 12-month comprehensive, individualized lifestyle intervention. Participants received a grouped startup course and monthly counseling, based on self-reported and electronically evaluated lifestyle behaviors. Patients with completed baseline and end of study measurements are included in the final analyses. Patients who did not complete end of study measurements are defined as dropouts. RESULTS: More completers (n = 61) vs. dropouts (n = 39) were married or living together (87 vs. 69%, p = .031), and significantly higher baseline physical activity levels (960 vs. 489 min.wk-1, p = .010), more healthy dietary choices (14 vs 11 points, p = .038) and fewer smokers (8 vs. 23%, p = .036) were observed among completers vs. dropouts. Logistic regression revealed younger (odds ratios (OR): 0.95, 95% confidence interval (CI): 0.91, 0.99) and more patients diagnosed with breast cancer vs. more severe cancer types (OR: 0.16, 95% CI: 0.04, 0.56) among completers vs. dropouts. Improvements were observed in completers healthy (37%, p < 0.001) and unhealthy dietary habits (23%, p = .002), and distress (94%, p < .001). No significant reductions were observed in physical activity levels. Patients treated with palliative intent did not reduce their physical activity levels while healthy dietary habits (38%, p = 0.021) and distress (104%, p = 0.012) was improved. DISCUSSION: Favorable and possibly clinical relevant lifestyle changes were observed in cancer patients undergoing curative or palliative chemotherapy after a 12-month comprehensive and individualized lifestyle intervention. Palliative patients were able to participate and to improve their lifestyle behaviors.

Mammographic density changes in surgical weight loss-an indication for personalized screening.

BACKGROUND: Obesity and high radiologic breast density independently increase breast cancer risk. We evaluated the effect of surgical weight loss on mammographic density (MD). METHODS: Patients undergoing bariatric surgery and screening mammography (MG) were identified, data regarding demographics, comorbidities, calculated and genetic breast cancer risk was collected. Patients had a MG before and after surgery. Fellowship-trained breast radiologists assigned Breast Imaging Reporting and Data System density categories. RESULTS: Patients underwent sleeve gastrectomy (n = 56) or gastric bypass (n = 7), 78% had hypertension, 48% had diabetes. Four had deleterious BRCA mutations, four were calculated high risk. Mean weight loss = 28.7 kg. Mean initial BMI = 44.3 kg/m2 (range:33-77), final BMI = 33.6 kg/m2 (range:20-62;p < 0.01). Density was unchanged in 53, decreased in 1, increased in 9. Of these 9(14%), 5 changed from almost entirely fatty to scattered MD, and 4 changed from scattered MD to heterogeneously dense. Mean weight loss of the 9 with increased MD was greater than the cohort (37.7vs.28.7 kg;p < 0.01). CONCLUSIONS: Surgical weight loss increased MD in 14%. Increased MD masks malignancies, patients may benefit from additional screening based on calculated risk assessments that include MD.

Bracketed radioactive seed localization vs bracketed wire-localization in breast surgery.

Multiple localizers placed in a bracketed fashion facilitates excision of radiographically extensive breast lesions. In this study, bracketed radioactive seed localization (bRSL) was compared to bracketed wire localization (bWL). We hypothesized that bRSL would achieve adequate margins and decrease re-operation rates with similar or less specimen volumes (SV) than bWL. Retrospective review identified patients who underwent bracketed breast procedures at an academic medical center. Data collected included patient demographics, tumor features, treatment variables, and surgical outcomes. Wilcoxon rank-sum test and chi-square test were used to compare continuous and categorical data, respectively. A multivariable logistic regression model was used to evaluate the association between re-excision and localization technique after adjusting for clinically relevant variables. Patients who underwent bWL were 3.9 times more likely to undergo re-excision compared to patients in bRSL group (OR=3.9, 95% CI: 2.0-7.4). Initial and total SV did not significantly differ between the two groups (P=.4). Patients were significantly more likely to undergo a mastectomy in the bWL group than in the bRSL group (24% vs 7%; P<.01). For patients undergoing excision of radiologically extensive breast lesions, bRSL serves as an alternative to bWL. In this retrospective study, bRSL was associated with a decreased re-excision rate with similar SV and a lower rate of mastectomy when compared to bWL.

Multimodality Imaging-based Evaluation of Single-Lumen Silicone Breast Implants for Rupture.

Breast implants are frequently encountered on breast imaging studies, and it is essential for any radiologist interpreting these studies to be able to correctly assess implant integrity. Ruptures of silicone gel-filled implants often occur without becoming clinically obvious and are incidentally detected at imaging. Early diagnosis of implant rupture is important because surgical removal of extracapsular silicone in the breast parenchyma and lymphatics is difficult. Conversely, misdiagnosis of rupture may prompt a patient to undergo unnecessary additional surgery to remove the implant. Mammography is the most common breast imaging examination performed and can readily depict extracapsular free silicone, although it is insensitive for detection of intracapsular implant rupture. Ultrasonography (US) can be used to assess the internal structure of the implant and may provide an economical method for initial implant assessment. Common US signs of intracapsular rupture include the "keyhole" or "noose" sign, subcapsular line sign, and "stepladder" sign; extracapsular silicone has a distinctive "snowstorm" or echogenic noise appearance. Magnetic resonance (MR) imaging is the most accurate and reliable means for assessment of implant rupture and is highly sensitive for detection of both intracapsular and extracapsular rupture. MR imaging findings of intracapsular rupture include the keyhole or noose sign, subcapsular line sign, and "linguine" sign, and silicone-selective MR imaging sequences are highly sensitive to small amounts of extracapsular silicone. ©RSNA, 2017.

Ultrasound-Guided Placement of Gold Fiducial Markers for Stereotactic Partial-Breast Irradiation.

OBJECTIVE: A novel technique of placing gold fiducial markers in the breast using ultrasound guidance was developed and performed in 51 of 55 consecutive postlumpectomy patients enrolled in a phase I dose escalation trial of accelerated partial-breast irradiation (APBI) using robotic-based stereotactic body radiation therapy (SBRT). CONCLUSION: All 51 postoperative patients underwent successful fiducial placement without complications. Our technique of placing gold fiducial markers in proximity to the seroma cavity is considered safe and effective for breast cancer patients being treated with APBI using robotic-based SBRT.

Preoperative Radioactive Seed Localization for Nonpalpable Breast Lesions: Technique, Pitfalls, and Solutions.

Iodine 125 ((125)I) radioactive seed localization has emerged as a reliable and safe alternative to wire localization for guidance during the surgical resection of nonpalpable breast lesions. The breast imager has a responsibility to be familiar with the general principles of this evolving technique, including its advantages and disadvantages as well as the technical differences involved in placement of seeds versus traditional wire localization. Although placement of (125)I seeds is conceptually similar to wire placement, there are additional technical considerations and safety measures that need to be addressed and implemented when radioactive seeds are used. We draw from our experience with more than 1000 cases of radioactive seed localization since inception of our program in 2009 to provide illustrative examples of not only the proper technique of radioactive seed localization, but also mishaps that may occur during this procedure, along with practical suggestions to prevent these problems. We examine some of the difficulties that we have encountered during radioactive seed localization at our institution, including bone wax mimicking the seed, the inadvertent deployment of seeds, the need for multiple seeds or supplemental wires, problematic seed locations, and difficulty in surgical retrieval of the seed. Recognizing the potential pitfalls of radioactive seed localization and understanding the appropriate guidelines and precautions for the safe, secure handling and placement of radioactive seeds is essential for a successful radioactive seed localization program.

Normative data of BMI and physical fitness in a Norwegian sample of early adolescents.

AIM: The purpose of the present study was to 1) provide normative data quantifying the physical fitness level and body mass index of 13-15-year-old Norwegian adolescents using a multi-component fitness assessment, and 2) compare the physical fitness of Norwegian teenagers with available European and International fitness data. METHODS: 1059 adolescents (529 males, 530 females) from 12 public schools in Kristians and were invited to testing at age 13, 14, and 15 years (Grades 8-10). Test participation was 75%-80%. The participants performed objectively anthropometrical measures (height and weight) and six field-based physical fitness tests. RESULTS AND CONCLUSIONS: As expected, sex differences in physical fitness expanded from age 13 to 15. Strength and power increased more in males than females. Aerobic capacity increased slightly in males while remaining stable or tending to decline in females. Balance and gross motor coordination improved identically in males and females from age 13 to 15. Compared to European and International reference data, the sample performed superior in endurance and balance, slightly above median in lower-body strength, but inferior in flexibility.

Not quite so fast: effect of training at 90% sprint speed on maximal and repeated-sprint ability in soccer players.

Abstract The aim of the present study was to investigate the effect of training at an intensity eliciting 90% of maximal sprinting speed on maximal and repeated-sprint performance in soccer. It was hypothesised that sprint training at 90% of maximal velocity would improve soccer-related sprinting. Twenty-two junior club-level male and female soccer players (age 17 ± 1 year, body mass 64 ± 8 kg, body height 174 ± 8 cm) completed an intervention study where the training group (TG) replaced one of their weekly soccer training sessions with a repeated-sprint training session performed at 90% of maximal sprint speed, while the control group (CG) completed regular soccer training according to their teams' original training plans. Countermovement jump, 12 × 20-m repeated-sprint, VO2max and the Yo-Yo Intermittent Recovery Level 1 test were performed prior to and after a 9-week intervention period. No significant between-group differences were observed for any of the performance indices and effect magnitudes were trivial or small. Before rejecting the hypothesis, we recommend that future studies should perform intervention programmes with either stronger stimulus or at other times during the season where total training load is reduced.