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Unveiling the Limitations of Continuous Glucose Monitoring: Insights from Fasting and OGTT with Advanced Clustering Analyses
Get PDFContinuous glucose monitoring (CGM) systems offer real-time glucose insights but are limited by temporal lags and variability compared to capillary blood glucose (CBG) and venous blood measurements. These limitations are particularly pronounced during fasting and oral glucose tolerance tests (OGTT), where accurate glucose tracking is critical. However, gaps remain in understanding how CGM performance compares to traditional methods in capturing glucose trends, variability, and clinical outliers. PURPOSE: This study addresses these gaps by evaluating the accuracy, variability, and clustering efficiency of CGM compared to CBG and venous glucose measurements during fasting and OGTT. METHODS: A cohort of 26 participants underwent fasting and OGTT with glucose levels measured via CGM, CBG, and venous blood at seven time points. Time-series analysis, k-means clustering, and DBSCAN identified trends, outliers, and clustering efficiencies across modalities. RESULTS: During fasting, CGM lagged 21 ± 2 minutes behind venous glucose, underestimated variability by 18% (p = 0.01), and failed to capture 12% of rapid glucose transitions. Venous glucose showed the least variability (SD: 13.13), while CGM exhibited the highest (SD: 44.36). In OGTT, CGM demonstrated a mean lag of 14 ± 3 minutes relative to CBG, with peak glucose discrepancies at 60 minutes (CGM: 192.8 ± 58.71 mg/dL; CBG: 179.17 ± 46.3 mg/dL). Clustering revealed that DBSCAN effectively isolated outliers, identifying extreme glucose deviations (CGM \u3e 300 mg/dL or CBG \u3e 275 mg/dL), while k-means smoothed over these anomalies. CONCLUSION: CGM\u27s temporal lag and variability compromise its clinical accuracy, particularly during rapid glucose fluctuations. While CGM excels in detecting trends, CBG and venous glucose provide more reliable point measurements. Enhanced CGM calibration and the integration of advanced clustering methods are essential to improving its diagnostic utility and clinical reliability
The Effects of Cognitive Demands on Landing Stability during Single-Leg Landings
Get PDFNon-contact anterior cruciate ligament (ACL) injuries commonly occur during the early deceleration phase of one-leg landing. While the risk of ACL injury increases with concurrent cognitive demands such as attention, reaction time or inhibitory control, only a few studies have investigated the association between cognitive function and unplanned landing mechanics under the jump-and-land movement paradigm. PURPOSE: The purpose of this study was to determine the biomechanical costs of single leg landing as a function of inhibitory control applied for the selection of landing limbs. METHODS: Participants (6 females and 8 males, 23.4 ± 5.2 years) were required to perform three successive trials of countermovement jump-and-land for each foot under three different anticipation conditions (i.e., planned (P), unplanned-compatible (UP-C), and unplanned-incompatible (UP-IC)). The indication of the requested landing leg was delivered by visual cues on the screen (i.e., left or right footprint) either before in planned condition or after take-off in unplanned condition. In trials with green color footprint participants were required to land with ipsilateral limb (planned & unplanned-compatible), and land with contralateral limb in trials with red color footprint (unplanned-incompatible). The landing direction (left or right) was randomized. Ground Reaction Force (GRF) was measured by force plate and vertical GRF (vGRF) and center of pressure (COP) characteristics were compared between the conditions. RESULTS: There were no significant differences in peak vGRF and Time-to-Stabilization (TTS) between the conditions, nor the landing feet. Measures in COP variables did not exhibit the differences between the landing feet. However, landing stability measured by COP 95% ellipse area (cm2) (P = 54.9 ± 3.7 and UP-IC = 95.4 ± 14.2), COP path length (m) (P = 0.67 ± 0.03 and UP-IC = 0.75 ± 0.05), and COP mean velocity (m/s2) (P = 0.27 ± 0.01 and UP-IC = 0.30 ± 0.02) was significantly greater in UP-IC than P condition (ps \u3c 0.05). CONCLUSION: While landing stability between P and UP-C was not significantly different, unplanned landing costs (greater values in COP measures) were associated with increased cognitive function (i.e., UP-IC). It can be inferred that the interference between cognitive and motor demands (i.e., incompatible visual stimuli) adversely affected single leg landing stability. No significant differences in time-to-stabilization (TTS) may indicate that greater postural fluctuations seem to affect only the early landing phase (e.g., ~ 3 sec), and this timeframe is sufficient for participants to regain their balance, regardless of the postural disturbances after landing. The findings from the study can help to clarify the association between cognitive function and unplanned landing stability, and its significance on the injury and performance in landing
Mental Toughness as a Catalyst for Social Team Cohesion: A Longitudinal Study in Female Collegiate Dancers
Get PDFCohesion bridges psychological and tactical aspects of how teams are structured and operate, significantly influencing both individual and team performance. Research has highlighted its particularly strong impact on women’s athletic success. Studies also show that women tend to prioritize social harmony, resolve conflicts collaboratively, and rely more on interpersonal relationships for team cohesion. While task-related cohesion (e.g., achieving performance goals) is often stable in elite athletes, social cohesion remains a malleable area for intervention. Mental toughness (MT), a trainable personal capacity, is theorized to enhance performance consistency under stress. However, MT’s role in fostering team cohesion, particularly social cohesion, remains underexplored in female sports teams. PURPOSE: To examine whether social cohesion responds differently than task cohesion to an MT intervention, and to identify which MT key dimensions contribute to improvements in social cohesion among elite female athletes. METHODS: A longitudinal study (T0–T5) was conducted with a convenience sample of 33 female collegiate dancers participating in weekly MT workshops over 6 weeks. Workshops focused on education and skill acquisition of MT’s eight key dimensions (e.g., buoyancy, emotion regulation, facing adversity). The Mental Toughness Index (MTI) served to weekly measure MT levels. Cohesion was also assessed weekly using the Group Environment Questionnaire (GEQ; four subscales), which measures (A) social cohesion: (i) Individual Attraction to Group–Social (ATGS; range: 4–36) and (ii) Group Integration–Social (GIS; range: 4–36); and (B) task cohesion: (iii) Individual Attraction to Group–Task (ATGT; range: 5–45) and (iv) Group Integration–Task (GIT; range: 5–45). A linear mixed-effects model was employed in MATLAB to analyze changes in overall MT, MT key dimensions, overall cohesion, and GEQ subscales. RESULTS: Social cohesion improved: ATGS: F(1,32) = 9.85, p = .004; GIS: F(1,32) = 4.32, p = .042. Task cohesion did not change (Ceiling Effect): ATGT: F(1,32) = 1.23, p = .27. GIT: F(1,32) = 0.78, p =.38. The MT key dimensions contributing to social cohesion improvements included: (1) Emotion Regulation: ATGS: β = 0.85, p = .005; GIS: β = 0.68, p = .021 and (2) Overcoming Adversity: ATGS: β = 0.64, p = .034; GIS: β = 0.55, p = .048. CONCLUSION: The MT intervention successfully enhanced social cohesion by improving two MT key dimensions, emotion regulation and facing adversity. These findings support previous research suggesting that athletes who effectively manage emotions and overcome adversity foster stronger social bonds, build greater team trust, and create more cohesive and resilient team environments through shared challenges and mutual support. Given the strong link between cohesion and performance in female athletes, these findings emphasize the potential value of integrating MT strategies into team development programs. Future research should further explore gender-specific approaches to optimizing cohesion and performance in female sports teams across different sports and settings
Patellofemoral Syndrome
Get PDFCLINICAL PRESENTATION & EXAM: Patellofemoral syndrome is a common cause of knee pain, particularly in young female athletes. Studies suggest that multiple factors contribute to its development, including patellar maltracking, imbalance between the vastus lateralis and vastus medialis, hip instability and weakness, hamstring imbalance and tightness, and rear-foot eversion. Patients typically present with anterior knee pain, especially during weight-bearing activities that involve knee flexion. The condition can also cause knee stiffness after prolonged sitting with the knee flexed and may lead to knee buckling due to quadriceps weakness. Pain often intensifies with squatting. Tight hamstrings have been linked to patellofemoral syndrome, as simultaneous contraction of the hamstrings and quadriceps increases force on the knee joint. Hamstring tightness may be observed during a passive knee extension test. ANATOMY & PATHOLOGY: The patellofemoral joint consists of the patella and the distal trochlea of the femur. The patella plays a crucial role in knee flexion, acting as a lever to enhance the efficiency of the quadriceps. It is connected to the quadriceps tendon and the patellar ligament. The patella is stabilized by surrounding muscles, including the rectus femoris, vastus lateralis, and vastus medialis obliquus. A Q angle exceeding 15-20 degrees is associated with an increased risk of patellofemoral syndrome. DIAGNOSTIC TESTING & CONSIDERATIONS: Diagnosing patellofemoral syndrome is based on a patient’s history and physical examination findings. Among manual maneuvers, the patellar tilt test has the highest likelihood ratio for identifying a true positive result. Additional tests, such as the patellar apprehension test or Clarke’s test, may also aid in evaluation. Gait analysis can reveal signs of patellofemoral syndrome, including exaggerated lumbar lordosis, asymmetric hip height, foot eversion, or quadriceps atrophy. Imaging may be useful for ruling out other conditions, such as osteoarthritis, fractures, or osteochondritis, if these are suspected based on the physical examination. TREATMENT & RETURN TO ACTIVITY: The treatment for patellofemoral syndrome is primarily non-operative, focusing on a conservative approach. Physical therapy is the most studied form of treatment, though no single exercise has been proven to be the most effective. Therapy should be individualized, with an emphasis on strengthening the hip, trunk, and knee muscles. Taping has shown success in addressing lateral patellar maltracking and patellar tilt. When combined with exercise, adhesive taping has demonstrated better results than exercise alone. The most commonly used taping technique is the McConnell method. Additionally, patellar braces can help manage patellar maltracking and pain levels
Impact of Electrical Muscle Stimulation During Prolonged Sitting Combined with Mental Stress - A Pilot Study
Get PDFMental stress superimposed on prolonged sitting is a common encounter. Both conditions are known to induce vascular dysfunction and impair executive function. While physical activity during sitting can mitigate these adverse effects, such activity is not always permissible for college students studying for important exams and office workers approaching critical deadlines. Electrical muscle stimulation (EMS) of the lower limb muscles has been proposed as a potential alternative to voluntary exercise and might help preserve vascular and cognitive function under these conditions. PURPOSE: This pilot study investigated whether EMS could attenuate arterial stiffening and cognitive decline induced by combined prolonged sitting and mental stress. METHODS: So far, three young healthy adults (mean age: 27 ± 1 years) completed a 3-hour sitting protocol. Mental stress tasks using mental arithmetic tests were performed at 30, 90, and 150 minutes after the start of sitting. In the EMS condition, EMS was applied to the thigh muscles following each stress task, whereas no EMS was applied in the control (CON) condition. Arterial stiffness was assessed using carotid-femoral pulse wave velocity (cfPWV) and femoral-ankle PWV (faPWV). Cognitive function was evaluated using a Go/No-go task before and after the prolonged sitting. RESULTS: After prolonged sitting, cfPWV did not change in either trial (CON: 653 ± 64 to 682 ± 74 cm/sec, EMS: 689 ± 24 to 653 ± 33 cm/sec). Compared with baseline, peripheral arterial stiffness as assessed by faPWV increased markedly after prolonged sitting in the CON trial (CON: 820 ± 35 to 913 ± 46 cm/sec), whereas the increase in the EMS trial was attenuated (EMS: 802 ± 31 to 867 ± 88 cm/sec). In contrast, the reaction time in the Go/No-go task increased in the CON trial (481 ± 88 to 515 ± 74 msec) while decreased in the EMS trial (508 ± 35 to 471 ± 20 msec). CONCLUSION: These findings suggest that EMS tends to mitigate the increase in peripheral arterial stiffness and help preserve cognitive function during combined prolonged sitting and mental stress
Effect of Lower Body Compression Tights on Recovery from an acute bout of Exhaustive Exercise
Get PDFCompression garments are widely used in a variety of different fitness and sports settings to improve physical performance, mitigate fatigue responses, and enhance recovery. PURPOSE: This research study was designed to determine the potential effects of calibrated lower-body compression tights on recovery following an acute bout of exhaustive exercise. METHODS: Ten college-aged participants (6 males and 4 females) who were deemed physically active according to the criteria provided by the American College of Sports Medicine participated in this research. After providing informed consent, each participant completed a PAR-Q and an ACSM-AHA health questionnaire. Each participant\u27s physical data was collected and included height, weight, body composition. Participants were placed in an experimental group in a counterbalanced method to ensure equal group size and distribution of participates by sex. The groups were designated as either the lower body compression tights group (CG, n = 5, 3 males and 2 females) or the loose clothing group (CON, n = 5, 3 males and 2 females). Data was collected in pre-posttest design before a fatiguing bout of acute exercise and again following 24-hours of recovery wearing either compression tights or loose-fitting clothing. The participants completed a familiarization trial and returned for the first data collection trial following a 24-hour recovery period. A 10-minute dynamic warm-up was performed before each trial. After the dynamic warm-up participants performed a vertical jump test, a broad jump test, agility T-test, and a 40-yd sprint. Participants were then given a 2-minute recovery prior to participating in the fatiguing bout of exercise which included a 20-meter Beep Test. Following another 2-minute recovery participants repeated sets of 5 consecutive squat jumps followed by a 30-meter sprint until volitional fatigue. Participants then wore the garment designated by the group for the next 24 hours. After this recovery period the participants reported to the lab for follow-up testing. Percent change was calculated for pre-to-post scores on all tests and multiple analysis of variance (MANOVA) was used for statistical analysis between the groups with significance set at p £ 0.05. RESULTS: The MANOVA did not indicate any statistically significant differences between the groups (p = 0.704). CONCLUSION: Although not statistically significant, between groups data indicated less decrement in performance for the CG group for vertical jump, horizontal jump, agility T-test, and 40-yd sprint. The primary limitation of this research is the small sample size
No Impact of Cardiorespiratory Fitness on The Stress Responses to Firefighting
Get PDFFirefighting can exacerbate cardiovascular disease (CVD) risk and has been shown to elevate α-amylase (AA), secretory immunoglobulin-A (SIgA), and cortisol. Data suggest firefighters may not meet cardiorespiratory fitness (CRF) standards. It is unclear if CRF levels impact the stress response to firefighting. Given the premature mortality risk, there is a critical need to understand the impact of CRF on firefighting stress responses. PURPOSE: This study assessed the impact of CRF on the stress response to an LFTE. METHODS: Forty-four (n=44) firefighters completed a cardiopulmonary exercise test (CPXT) and an LFTE. V̇O 2max was estimated via the Foster equation. The occupational CRF standard of 42 ml/kg/min was used to establish a low-fitness group (LF; n=22) and a high-fitness group (HF; n=22). Salivary samples were collected pre (baseline), immediately post, and 30-min post the LFTE and analyzed for AA, SIgA, and cortisol. Data were analyzed via a general linear model (GLM) multivariate and univariate analysis. RESULTS: GLM multivariate analysis revealed an overall time effect (p\u3c0.001, ηₚ²=0.218) with no group x time effect (p=0.622, ηₚ²=0.026) for the salivary stress biomarkers. The univariate analysis revealed time effects for AA (p\u3c0.001, ηₚ²=0.248), SIgA (p\u3c0.001, ηₚ²=0.262), and cortisol (p=0.002, ηₚ²=0.140); however, no group x time effects were found for AA (p=0.486, ηₚ²=0.015), SIgA (p=0.502, ηₚ²=0.015), and cortisol (p=0.978, ηₚ²=0.000). Significantly higher AA (p=0.003), SIgA (p=0.003), and cortisol (p=0.003) concentrations were noted immediately post-LFTE than baseline concentrations. Only AA concentrations remained elevated at 30-min post-LFTE compared to baseline (p=0.003). There were no significant group effects for AA (p=0.261, ηₚ²=0.030), CORT (p=0.768, ηₚ²=0.002), or SIgA (p=0.353, ηₚ²=0.021). CONCLUSION: These data demonstrate the CRF level does not impact the physiological stress response to firefighting. Certainly, it is reasonable to believe that a more fit firefighter will be able to carry out physically demanding occupational tasks; however, future work should elucidate the impact that CRF may have on the stress response to fire-suppressive activities
Sexual Pleasure, Satisfaction, and Activities in Masters Track and Field Athletes
Get PDFSexual function is an important factor for quality of life and has been shown to decrease with aging but increase with exercise training. Masters athletes (MA) demonstrate substantial physical function, reduced disease risks, and enhanced mental outlook, compared with the general population (GP), in spite of their chronological age. Currently, it is unknown whether MA who engage in strenuous exercise on a regular basis possess greater sexuality than their predominantly sedentary peers. PURPOSE: To compare sexual history, desire, and satisfaction in male and female MA with the GP. METHODS: A 52-item survey that evaluated sexual function and history was distributed at the 2023 World Masters Athletics Championships in Poland. A total of 104 masters track and field athletes (41% women, aged 59±11 years) completed the survey, and responses were compared with responses from an American Association of Retired Persons (AARP) dataset (53% women, aged 60±10 years). Age-graded sports performance was calculated based on each athlete’s competition results. RESULTS: Sexual satisfaction was high and greater in MA than in the GP (3.7 vs 3.4, p=0.02). Engagements in sexual activities, including kissing, sexual touching, intercourse, and self-stimulation, were more frequent in MA than in the GP (all pCONCLUSION: Sexual pleasure, satisfaction, and activity are high and substantially greater among masters athletes than the general public
Differences in Perceived Readiness to train between two Menstrual Cycle Phases in Division II Female Athletes
Get PDFRecently, the effects of the menstrual cycle (MC) and hormonal fluctuations on performance outcomes and training readiness have received significant research focus, leading to the potential for more individualized and informed approaches in athlete training. Training readiness refers to an athlete´s state of balance between their current training load, fatigue, and potential risk of injury or illness. The MC is divided into two phases (± 28 days), commencing with the follicular or proliferative phase (days 1 to 13) followed by the luteal phase, also known as the secretory phase (days 14 to 28). Its hormonal fluctuation throughout the cycle can significantly affect an athlete´s readiness and thereby directly influencing overall performance outcomes. PURPOSE: The purpose of this study was to determine the potential differences between two stages of the menstrual cycle (early follicular & luteal phase) on subjective and objective readiness to train measures in Division II female athletes. METHODS: A repeated measures crossover design was used to determine differences in Heart Rate Variability (HRV), psychological readiness and jumping performance (JP). Fifteen participants completed all data collection (age = 19.6 ± 1.3 yrs., height = 164.67 ± 5.78 cm, weight = 62.44 ± 10.95 kg, body fat = 24.34 ± 6.46 %). Participants from track & field (n = 8), softball (n = 5) & cycling team (n = 2) arrived at the laboratory during the early follicular phase (days 1 to 7) and the early luteal phase (days 14 to 21) to perform to identical ST training in conjunction with their current training regimes. For each trial, participants completed a pre and post measurement including body composition assessment (dexa body composition), a three-minute heart rate variability measurement (Scosche Rhythm & Elite HRV phone application), a wellness questionnaire form and four consecutive maximal countermovement jumps with a 30 second rest period after each jump). RESULTS: Significant differences were found in the early luteal phase (p \u3c 0.01) compared to the early follicular phase. No significant differences were found for HRV (p = 0.62) & JP (p = 0.12) between the two phases. In the early luteal phases, athletes tend to be less negatively affected by psychological factors and appear more ready to work out, although this does not have a significant impact on performance metrics. CONCLUSION: Recent research has hypothesized a potential influence of hormonal fluctuations on performance and training variables. Our study concludes that in the early luteal phases, athletes tend to be less negatively affected by psychological factors and appear more ready to work out, although this does not have a significant impact on performance metrics. Simple sport science tools such as wellness questionnaires to measure psychological readiness, heart rate variability and jumping performance assessments can effectively monitor athlete´s training responses through the MC. These tools help enhance awareness and understanding of fluctuations in training readiness & performance
Principal Component Analysis of Force Plate Variables from Collegiate Athlete Countermovement Jumps
Get PDFDespite widespread use of countermovement jump (CMJ) assessments in athletic performance testing, research has focused on isolated kinetic metrics without addressing redundancy among variables. This oversight can obscure data interpretation and limit CMJ utility in sports performance analysis. Principal component analysis (PCA) offers a means to distill complex, multivariate data into key performance indicators. PURPOSE: To evaluate PCA outcomes on kinetic variables recorded during CMJ assessments to reduce data dimensionality and identify redundant measures. METHODS: Retrospective analysis of kinetic force data from dual force plate assessments was performed on 7,404 trials from 308 collegiate athletes (male = 127, female = 181) across 16 teams over 28 months. Each athlete performed 28 ± 33 jumps. Variables, selected per literature prevalence, were computed via the force plate system’s software. PCA appropriateness was confirmed using Kaiser-Meyer-Olkin (MSA \u3e .8) and Bartlett’s test (p \u3c .05). Principal components capturing 95% of variance were initially selected; only components with eigenvalues \u3e 1 were retained. Loadings, squared cosine (Cos²) values, and Pearson correlations among variables were examined using R (v4.43) and the factoextra package. RESULTS: Three principal components explained 95% of variance: PC1 accounted for 77.9% (eigenvalue = 9.3), PC2 for 10.7% (eigenvalue = 1.3), and PC3 for 6.4% (eigenvalue = 0.8). Given PC3’s eigenvalue below 1, further analysis focused on PC1 and PC2. Variables with the highest loadings on PC1 were linked to the eccentric–concentric transition, whereas PC2 predominantly comprised measures associated with jump height. Pearson correlations (r \u3e .80) were observed among most top-loaded variables, except Peak Braking Rate of Force Development. CONCLUSION: These findings emphasize that variations during the braking phase parallel propulsive outcomes in CMJ performance, underscoring the need for phase-specific analyses. The heterogeneous athletic sample may explain lower loadings and Cos² values relative to prior studies. Sport-specific evaluations are recommended to optimize CMJ performance metrics for sport science applications