The Association Between Pre-Pregnancy and First-Trimester Hair Cortisol and Preterm Birth: A Causal Inference Model.

Background Adverse life events and chronic psychological distress before and during pregnancy have frequently been associated with preterm birth (PTB) but the biological underpinnings remain unclear. We investigated the association between corticosteroid levels in pre-pregnancy and first-trimester hair and the risk of PTB. Methods We followed 1,808 pregnant women from a prospective pre-birth cohort study in Lima, Perú. Hair samples were taken at the end of the first pregnancy trimester. The two most proximal 3cm segments to the scalp (representing pre-pregnancy and first-trimester) were analyzed to obtain hair cortisol and cortisone concentrations (HCC and HCNC). PTB was defined as birth < 37 completed gestational weeks. We constructed four generalized propensity scores for pre-pregnancy and first-trimester HCC and HCNC to create corresponding inverse probability weights before fitting marginal structural models for estimating the effect of HCC and HCNC on PTB risk. Results Pre-pregnancy Log HCC was not independently associated with PTB risk (RR = 0.97; 95%CI: 0.79, 1.19). In contrast, one SD increase from the mean first-trimester Log HCC was independently associated with a 37% (95%CI: 1.11, 1.69) increased risk of PTB. Although imprecise, pre-pregnancy Log HCNC was negatively associated with PTB risk (RR = 0.84; 95%CI: 0.58, 1.20), whereas the association between first-trimester Log HCNC and PTB risk was positive (RR = 1.20; 95%CI: 0.87, 1.65). Conclusions Our findings show that chronic corticosteroid levels in early pregnancy are causally linked to PTB risk in pregnant Peruvian women. This finding contributes to understanding the biological underpinnings of PTB better to enhance PTB prevention.

Do you even exercise, ref? Exploring habits of Spanish basketball referees during practice and matches.

Background: Basketball referees are a vital part of the organised competition system, although they remain an "outgroup" in sport. While physical development and fitness programming are deemed necessary for basketball officiating excellence, there is a paucity of literature exploring strategies for physical fitness management in this population. Methods: This research was a nationwide cross-sectional, self-administered online survey conducted in 2021. A sample of 628 (531 males, 97 females) referees from 18 regional referee organisations in Spain provided individual responses to gather information on demographic details, level of participation in refereeing, physical fitness practices, and match-day exercise-based regimens. The data were described using summary statistics, and the associations of the assessed variables were subsequently calculated using contingency tables. Results: Our findings reveal that a large fraction of the Spanish basketball referee population focuses on aerobic (83%) and strength (73.6%) activities, while less attention is paid to speed (36.9%) and flexibility (23.2%), and agility, coordination, and balance tasks are somewhat overlooked. No significant differences were observed among the referee categories regarding weekly training days or session duration, with most training for 15-60 min per session. Elite referees were more likely to hire personal trainers and engage in strength and flexibility exercises. Sub-elite referees showed a higher tendency to perform stretching and joint mobility activities post-match, while regional referees did so less frequently. Approximately 30.7% of referees across all competitive levels engaged in re-warm-up (RW-U) activities, with stretching and joint mobility being the most prevalent. Conclusions: Spanish basketball referees participate in routine physical exercise and fitness practices, irrespective of their competition level. While warm-up activities are prevalent, some sub-elite and regional referees do not consistently perform them, and re-warm-up routines are not extensively embraced.

Joint movement patterns differ among male recreational runners with different running style.

The purpose of this study was to analyse the differences in joint kinematic patterns among runners with different spatiotemporal characteristics in the running cycle. Lower extremity kinematic data and spatiotemporal stride parameters were collected for ninety-two recreational runners during a treadmill run at a self-selected comfortable speed. A K-means clustering analysis was conducted on normalised stride cadence and Duty Factor to identify running style. Cluster 1 characterised by reduced stance times and low Duty Factor; Cluster 2, long stance times and low stride cadence; Cluster 3, high Duty Factor and stride cadence. Functional principal component analysis was used to identify patterns of variability between runners. Runners who used a combination of high cadence and Duty Factor showed differences in hip, knee and ankle sagittal kinematics compared to other runners. On the contrary, the joint kinematics was not altered when the Duty Factor was increased along with a decrease in the stride cadence. This study has demonstrated that the combination of several spatial-temporal parameters of the running cycle should be considered when analysing the movement pattern of the lower limb.

Fourteen-item perceived stress scale assessment using item response theory among pregnant women.

The current study aimed to assess the psychometric properties of the Spanish language version of the 14-item Perceived Stress Scale (PSS-S) in a population of pregnant women who speak Spanish in Peru using item response theory (IRT). Our study consisted of 5,435 pregnant women who participated in the Pregnancy Outcomes Maternal and Infant Study (PrOMIS) cohort in Peru. Exploratory and confirmatory factor analyses were conducted to determine dimensionality of the scale in this population, and item response theory was conducted to determine the applicability of the PSS. The PSS consisted of a 2-factor questionnaire measuring perceived stress and coping capacity accounting for 77% of variability. The IRT analysis showed differences in item difficulty and discrimination. Item difficulty represents the level of the latent construct where 50% of respondents endorse a particular response, and item discrimination determines the rate of change of the probability of endorsing an item for differing ability levels. For the first factor, perceived stress, item 12 was the least difficult and item 2 was the most difficult. For the second factor, coping capacity, item 9 was the least difficult and item 6 was the most difficult. The Spanish version of the 14-item PSS can be a useful assessment tool for perceived stress, but more IRT should be done to delve further into the psychometric properties of the questionnaire to inform clinicians and policy makers more appropriately.

Genetic association study of Preterm birth and Gestational age in a population-based case-control study in Peru: Genetics of PTB and GA in pregnant women in Peru.

Preterm birth (PTB) is an adverse pregnancy outcome affecting ~15 million pregnancies worldwide. Genetic studies have identified several candidate loci for PTB, but results remain inconclusive and limited to European populations. Thus, we conducted a genome-wide association study (GWAS) of PTB and gestational age at delivery (GA) among 2,212 Peruvian women. PTB cases delivered ≥ 20 weeks' but < 37 weeks' gestation, while controls delivered at term (≥ 37 weeks but < 42 weeks). After imputation (TOPMED) and quality control, we assessed the association of ~6 million SNPs with PTB and GA using multivariable regression models adjusted for maternal age and the first two genetic principal components. In silico functional analysis (FUMA-GWAS) was conducted among top signals detected with an arbitrary P < 1.0×10-5 in each GWAS. We sought to replicate genetic associations with PTB and GA identified in Europeans, and we developed a genetic risk score for GA based on European markers. Mean GA was 30 ± 4 weeks in PTB cases (N=933) and 39 ± 1 in the controls (N=1,279). PTB cases were slightly older and had higher C-sections and vaginal bleeding than controls. No association was identified at genome-wide level. Top suggestive (P < 1.0×10-5) signals were seen at rs13151645 (LINC01182) for PTB, and at rs72824565 (CTNNA2) for GA. Top PTB variants were enriched for biological pathways associated with polyketide, progesterone, steroid hormones, and glycosyl metabolism. Top GA variants were enriched in intronic regions and cancer pathways, and these genes were upregulated in the brain and subcutaneous adipose tissue. In combination with non-genetic risk factors, top SNPs explained 14% and 15% of the phenotypic variance of PTB and GA in our sample, but these results need to be interpreted with caution. Variants in WNT4 associated with GA in Europeans were replicated in our study. The genetic risk score based in European markers, was associated with a 2-day longer GA (R2=0.003, P=0.002) per standard deviation increase in the score in our sample. This genetic association study identified various signals suggestively associated with PTB and GA in a non-European population; they were linked to relevant biological pathways related to the metabolism of progesterone, prostanoid, and steroid hormones, and genes associated with GA were significantly upregulated in relevant tissues for the pathophysiology of PTB based on the in-silico functional analysis. None of these top variants overlapped with signals previously identified for PTB or GA in Europeans.

Correlates of preconception and pregnancy hair cortisol concentrations.

Assessing factors that influence chronic stress biomarkers like hair cortisol concentrations (HCCs) in pregnancy is critical to prevent adverse pregnancy outcomes. Thus, we aimed to identify correlates of HCC preconception and during pregnancy. 2,581 pregnant women participated in the study. HCC was available at four time periods: pre-pregnancy (0-3 months preconception, n = 1,023), and in the first (1-12 weeks, n = 1,734), second (13-24 weeks, n = 1,534), and third (25-36 weeks, n = 835) trimesters. HCC was assessed using liquid chromatography tandem mass spectrometry (LC-MS/MS). Sociodemographic, pregnancy- and hair-related characteristics, and measures of psychosocial stress, were interrogated as potential correlates of HCC. Spearman correlations, paired t-tests, and ANOVA were used to assess differences in log-transformed values of HCC (logHCC) across maternal characteristics. Multivariable linear regressions were used to identify the correlates of HCCs after adjusting for confounders. Mean logHCC values increased across the four prenatal periods (P < 0.001). In multivariable analyses, pre-pregnancy BMI was consistently associated with all HCCs, while gestational age, economic hardship, hair dyeing, and depression, showed time-specific associations with HCC. In conclusion, this study showed evidence of factors influencing HCC levels before and during pregnancy. The most consistent association was seen with pre-pregnancy BMI. Depression was also associated with HCC concentrations.

Association between trauma exposure and glucocorticosteroid concentration in hair during pregnancy.

BACKGROUND: Traumatic events, including child abuse and intimate partner violence, are highly prevalent among women of child-bearing age. These traumatic experiences may impact maternal and offspring physical and mental health. A proposed mechanism for these effects is maternal hypothalamic-pituitary-adrenal (HPA) axis dysregulation which can be measured using hair corticosteroid levels. AIMS: This study aims to examine the association of child abuse and intimate partner violence exposure with HPA axis functioning, as measured by hair corticosteroid levels in a cohort of pregnant women. METHODS: We included data from 1822 pregnant women (mean gestational age 17 weeks) attending a prenatal clinic in Lima, Peru. We extracted cortisol and cortisone concentrations from hair samples using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Each participant provided 6-cm hair samples: 3 cm hair segment closest to the scalp reflecting HCC in early pregnancy (first three months), and 3-6 cm from the scalp reflecting HCC in pre-pregnancy (three months prior to conception). Multivariable linear regression procedures were used to assess the association between maternal trauma exposure and hair corticosteroid levels. RESULTS: Overall, women who experienced child abuse on average had higher levels of cortisol (p < 0.01) and cortisone (p < 0.0001) after adjustment for age, race, adult access to basic foods and hair treatments. For the hair segment reflecting early pregnancy, presence of child abuse was associated with a 0.120 log unit increase in cortisol and a 0.260 log unit increase in cortisone (p < 0.001). For the hair segment reflecting pre-pregnancy, a history of child abuse was associated with a 0.100 log unit increase in cortisol and a 0.180 log unit increase in cortisone (p < 0.01). Results also suggested an impact of intimate partner violence on HPA regulation; however, associations were not statistically significant after controlling for child abuse. CONCLUSIONS: These results underscore the long-lasting impacts of exposure to adversity and trauma during early life. Our study findings will have implications for research investigating HPA axis function and long-term effects of violence on corticosteroid regulation.

Changes in Muscle Deoxygenation During Squat Exercise After 6-Week Resistance Training With Different Percentages of Velocity Loss.

ABSTRACT: Costilla, M, Casals, C, Marín-Galindo, A, Sánchez-Sixto, A, Muñoz-López, A, Sañudo, B, Corral-Pérez, J, and Ponce-González, JG. Changes in muscle deoxygenation during squat exercise after 6-week resistance training with different percentages of velocity loss. J Strength Cond Res 37(8): 1573-1580, 2023-The present study compared, for the first time, the effects of 6 weeks of 20% (20VL) vs. 40% (40VL) velocity loss (VL) resistance training (RT) programs on muscle oxygen dynamics during the squat exercise. Twenty-three young men (21.4 ± 2.4 years) were randomly allocated into the 20VL group ( n = 8), 40VL group ( n = 7), or control group (CG; n = 8). The RT program consisted of 3 sets of Smith machine back squat exercise at 20VL or 40VL with a 3-minute rest between sets, twice per week for 6 weeks. Tissue oxygenation index (TOI) was measured using near-infrared spectroscopy in the vastus medialis and vastus lateralis during a squat test (8-repetition 1 m·s -1 load test), and the maximum (maxTOI) and minimum (minTOI) TOIs were measured during a 3-min recovery period. After the 6-week RT program, TOI increased significantly at the beginning of the test in both muscles (during the first 4 repetitions in the vastus lateralis and 5 repetitions in the vastus medialis) in the 20VL group ( p < 0.05), with nonsignificant changes in the 40VL group and CG. The maxTOI was significantly increased in the vastus medialis (+3.76%) and vastus lateralis (+3.97%) after the training only in the 20VL group ( p < 0.05). The minTOI in the vastus medialis reached during the test remained unchanged postintervention for both training groups, with the CG showing significantly higher values compared with the 20VL group (+14.1%; p < 0.05). In conclusion, depending on the VL reached during a squat RT program, different changes in muscle oxygen dynamics can be expected. Training at 20% of VL improves metabolic efficiency and the reoxygenation peak after the set.

Maternal hair cortisol concentrations and its association with increased insulin resistance in midpregnancy.

PURPOSE: Stress and elevated maternal glycemia have negative effects on pregnancy. We evaluated the association of hair cortisol concentrations (HCC), a marker of chronic stress, with insulin resistance and gestational diabetes (GDM). METHODS: In total, 527 women from Lima, Peru, provided a hair sample in the second trimester of their pregnancy to measure HCC using liquid chromatography-tandem mass spectrometry. Each 6 cm of hair captured HCC in early (T1=1-12 weeks) and midpregnancy (T2 = 13-24 weeks). GDM diagnosis was conducted in midpregnancy. Multivariable regression models adjusted for putative risk factorsincluding maternal sociodemographic factors, diabetes history, and hair characteristics, were used to estimate the association of HCC with GDM and various glycemic traits. RESULTS: GDM was diagnosed in 122 (23%) women. Mean HCC across pregnancy was T1 = 3.7 (±3.4) pg/mg and T2 = 4.8 (±3.4) pg/mg. HCC was associated with increased log-transformed units of fasting insulin (T1 = 0.15 [0.03, 0.27], T2 = 0.17 [0.04, 0.30]), homeostasis model assessment for insulin resistance (T1 = 0.14 [0.01, 0.26], T2 = 0.17 [0.03, 0.30]), and homeostasis model assessment for ß-cell function (T1 = 0.20 [0.05, 0.34], T2 = 0.20 [0.04, 0.36]), but not with GDM (T1 = 0.95 [0.63, 1.40], T2 = 1.11 [0.74, 1.67]). CONCLUSIONS: Elevated maternal HCC was associated with abnormal insulin homeostasis in pregnancy. Dysregulation of the hypothalamic-pituitary-adrenal axis, as reflected by high HCC, may also contribute to insulin resistance syndrome in pregnancy.

Comparative Performance of the Resilience Inventory (IRES) and Resilience Scale-14 (RS-14) Spanish Versions Among Postpartum Adolescent Mothers.

We sought to evaluate the psychometric properties of two resilience scales; the Resilience Inventory (IRES) and the 14-item Resilience Scale (RS-14) among Peruvian postpartum adolescent mothers. This cross-sectional study included 785 adolescent mothers who delivered at a maternity hospital in Lima, Peru. The Spanish versions of IRES and RS-14 were used to evaluate the properties of the measures. We examined reliability using Cronbach's alpha. We used exploratory factor analysis (EFA) and confirmatory factor analysis (CFA) to assess the construct validity and factor structures of the two scales. Both scales had good internal consistency (Cronbach's alpha > 0.7). Correlation between IRES and RS-14 scores was fair (r = 0.53). The EFA results of both scales yielded a three-factor structure. EFA including all items from IRES and RS-14 yielded a six-factor structure. CFA results corroborated the original seven-factor structure for IRES and yielded measures indicating a good level of goodness of fit (comparative fit index of 0.93) and accuracy (root mean square error of approximation of 0.07). Overall, Spanish language versions of both the IRES and the RS-14 are reliable and valid scales for assessing resilience among Peruvian postpartum adolescent mothers. Additional research is needed to integrate culturally-specific traits into resilience measures.

Validation of the Patient Health Questionnaire-9 (PHQ-9) for Detecting Depression Among Pregnant Women in Lima, Peru.

Depression during pregnancy is linked to adverse perinatal and offspring outcomes. The Patient Health Questionnaire-9 (PHQ-9) has been validated for identifying depression in pregnant women in limited cultural contexts. Construct validity and reliability have been assessed in Lima, Peru, but criterion validity has not. This study aimed to comprehensively evaluate the PHQ-9 among pregnant Peruvian women in the Pregnancy Outcomes, Maternal and Infant Study (PrOMIS). Using Composite International Diagnostic Interview (CIDI) criteria for past-12-month major depressive disorder as the reference standard, sensitivity, specificity, and predictive value of the PHQ-9 for detecting depression were assessed at various cutpoints of the PHQ-9. Confirmatory factor analysis (CFA) was used to evaluate one- and two-factor structures for the PHQ-9. Cronbach's alpha was computed for the entire PHQ-9 scale and for subscales supported by CFA. A cutpoint of ≥8 maximized combined sensitivity (61%) and specificity (62%). At this cutpoint, positive predictive value was low (15%) and negative predictive values was high (93%). Reliability for the full scale was high (α=0.80). Both one- and two-factor solutions were appropriate for this population, but a two-factor solution containing an affective/mood factor (α=0.67) and a somatic factor (α=0.75) was optimal (CFI=0.93, RMSEA=0.075). Among pregnant women in Lima, screening with the PHQ-9 can identify those in need of mental health care, but may identify a large number of false positive cases.

Association between Ancestry-Specific 6q25 Variants and Breast Cancer Subtypes in Peruvian Women.

BACKGROUND: Breast cancer incidence in the United States is lower in Hispanic/Latina (H/L) compared with African American/Black or Non-Hispanic White women. An Indigenous American breast cancer-protective germline variant (rs140068132) has been reported near the estrogen receptor 1 gene. This study tests the association of rs140068132 and other polymorphisms in the 6q25 region with subtype-specific breast cancer risk in H/Ls of high Indigenous American ancestry. METHODS: Genotypes were obtained for 5,094 Peruvian women with (1,755) and without (3,337) breast cancer. Associations between genotype and overall and subtype-specific risk for the protective variant were tested using logistic regression models and conditional analyses, including other risk-associated polymorphisms in the region. RESULTS: We replicated the reported association between rs140068132 and breast cancer risk overall [odds ratio (OR), 0.53; 95% confidence interval (CI), 0.47-0.59], as well as the lower odds of developing hormone receptor negative (HR-) versus HR+ disease (OR, 0.77; 95% CI, 0.61-0.97). Models, including HER2, showed further heterogeneity with reduced odds for HR+HER2+ (OR, 0.68; 95% CI, 0.51-0.92), HR-HER2+ (OR, 0.63; 95% CI, 0.44-0.90) and HR-HER2- (OR, 0.77; 95% CI, 0.56-1.05) compared with HR+HER2-. Inclusion of other risk-associated variants did not change these observations. CONCLUSIONS: The rs140068132 polymorphism is associated with decreased risk of breast cancer in Peruvians and is more protective against HR- and HER2+ diseases independently of other breast cancer-associated variants in the 6q25 region. IMPACT: These results could inform functional analyses to understand the mechanism by which rs140068132-G reduces risk of breast cancer development in a subtype-specific manner. They also illustrate the importance of including diverse individuals in genetic studies.

Poor sleep Quality and Obstructive Sleep Apnea are Associated with Maternal Mood, and Anxiety Disorders in Pregnancy.

BACKGROUND: Previous studies suggest sleep quality and obstructive sleep apnea (OSA) may be associated with psychiatric symptoms, including depression, anxiety, and posttraumatic stress disorder (PTSD). However, few studies have examined the relationship between sleep quality and OSA with maternal psychiatric symptoms during pregnancy, a state of vulnerability to these disorders. OBJECTIVE: The objective of our study is to examine the association between poor sleep quality and sleep apnea with antepartum depression, anxiety, and PTSD among pregnant women. METHODS: A cross-sectional study was conducted among women seeking prenatal care in Lima, Peru. Sleep quality was measured using the Pittsburgh Sleep Quality Index, and the Berlin questionnaire was used to identify women at high risk for OSA. Depression, generalized anxiety, and PTSD symptoms were measured using the Patient Health Questionnaire-9, Generalized Anxiety Disorder Assessment, and PTSD Checklist - Civilian Version. Multivariate logistic regression procedures were used to estimate adjusted odds ratios (aOR) and 95% confidence intervals (95% CI). RESULTS: Approximately 29.0X% of women had poor sleep quality, and 6.2% were at high risk for OSA. The prevalence of psychiatric symptoms was high in this cohort with 25.1%, 32.5%, and 30.9% of women reporting symptoms of antepartum depression, antepartum anxiety, and PTSD, respectively. Women with poor sleep quality had higher odds of antepartum depression (aOR = 3.28; 95%CI: 2.64-4.07), generalized anxiety (aOR = 1.94; 95%CI: 1.58-2.38), and PTSD symptoms (aOR = 2.81; 95% CI: 2.28-3.46) as compared with women who reported good sleep quality. Women with a high risk of OSA had higher odds of antepartum depression (aOR = 2.36; 95% CI: 1.57-3.56), generalized anxiety (aOR = 2.02, 95% CI: 1.36-3.00), and PTSD symptoms (aOR = 2.14; 95%CI: 1.43-3.21) as compared with those with a low risk of sleep apnea. CONCLUSIONS: Poor sleep quality and high risk of OSA are associated with antepartum depression, generalized anxiety, and PTSD symptoms among pregnant women. Further characterizations of the associations of these prevalent sleep, mood, and anxiety conditions among pregnant women could aid in evaluating and delivering optimal perinatal care to women with these comorbidities.

Association of morningness-eveningness with psychiatric symptoms among pregnant women.

In the present study, we examined associations between circadian preference and psychiatric symptoms among 1,796 pregnant women from Lima, Peru. One quarter were classified as evening types. Compared to morning types, evening type pregnant women had increased odds of generalized anxiety (OR = 1.44; 95%CI: 1.12-1.86) and posttraumatic stress disorder (OR = 1.38; 95%CI: 1.07-1.78). Although there was a positive trend, evening chronotype was not significantly associated with elevated odds of depression (OR = 1.23; 95%CI: 0.94-1.61). Future studies are warranted to help understand the underlying behavioral, biological, and genetic pathways of these associations. Assessing circadian preference may help clinicians identify pregnant women at risk for psychiatric symptoms.

Maternal-fetal genetic interactions, imprinting, and risk of placental abruption.

RESULTS: Abruption cases were more likely to experience preeclampsia, have shorter gestational age, and deliver infants with lower birthweight compared with controls. Models with MFGI effects provided improved fit than models with only maternal and fetal genotype main effects for SNP rs12530904 (p-value = 1.2e-04) in calcium/calmodulin-dependent protein kinase [CaM kinase] II beta (CAMK2B), and, SNP rs73136795 (p-value = 1.9e-04) in peroxisome proliferator-activated receptor-gamma (PPARG), both MB genes. We identified 320 SNPs in 45 maternally-imprinted genes (including potassium voltage-gated channel subfamily Q member 1 [KCNQ1], neurotrimin [NTM], and, ATPase phospholipid transporting 10 A [ATP10A]) associated with abruption. Top hits included rs2012323 (p-value = 1.6E-16) and rs12221520 (p-value1.3e-13) in KCNQ1, rs8036892 (p-value = 9.3E-17) and rs188497582 in ATP10A, rs12589854 (p-value = 2.9E-11) and rs80203467 (p-value = 4.6e-11) in maternally expressed 8, small nucleolar RNA host (MEG8), and rs138281088 in solute carrier family 22 member 2 (SLC22A2) (p-value = 6.8e-9). CONCLUSIONS: We identified novel PA-related maternal-fetal MB gene interactions and imprinting effects that highlight the role of the fetus in PA risk development. Findings can inform mechanistic investigations to understand the pathogenesis of PA.

Effects of Different Velocity Loss Thresholds on Passive Contractile Properties and Muscle Oxygenation in the Squat Exercise Using Free Weights.

ABSTRACT: Muñoz-López, A, Marín-Galindo, A, Corral-Pérez, J, Costilla, M, Sánchez-Sixto, A, Sañudo, B, Casals, C, and Ponce-González, JG. Effects of different velocity loss thresholds on passive contractile properties and muscle oxygenation in the squat exercise using free weights. J Strength Cond Res 36(11): 3056-3064, 2022-The current study assessed the impact between different velocity loss thresholds on changes in the muscle contractile properties and muscle oxygenation after a single resistance training (RT) session. Thirty physically active men participated in a crossover study performing 3 sets of the squat exercise at a lifted speed of ≈0.75 m·s -1 , with 2 different velocity loss thresholds: 20% (VL20) vs 40% (VL40) in a randomized order. Contractile properties of the knee extensor muscles were tested using tensiomyography. In addition, muscle oxygenation was continuously measured from baseline until the end of the exercise session. The vastus lateralis showed a significant moment by condition interaction in time delay ( p = 0.044), muscle displacement ( p = 0.001), and contraction velocity ( p = 0.007), with greater reductions in VL40. In both trainings, oxygenated hemoglobin and tissue oxygen index decreased, whereas deoxygenated hemoglobin increased (moment as the main effect, p < 0.05), but without a moment by condition interaction. VL40 showed a lower deoxygenation slope in set 1 (-0.468%·s -1 , p = 0.001) and set 3 (-0.474%·s -1 , p = 0.037) as well as higher losses in set 1 (-41.50%, p = 0.003), set 2 (-41.84%, p = 0.002), and set 3 (-62.51%, p < 0.001), compared with VL20. No differences were found in the recovery period between conditions. In conclusion, during the RT program design, coaches and athletes should consider that VL40 produces higher mechanical and neuromuscular impairments than VL20, which seems to be necessary for hypertrophy to occur; however, VL40 also produces a longer period of lower oxygen supply than VL20, which can induce fast-to-slow muscle fiber transition.

Mobile Technology Access and Use Among Adolescent Mothers in Lima, Peru: Mixed Methods Study.

BACKGROUND: Research shows promise for the use of mobile health interventions to improve access to care for mothers and infants. Although adolescent mothers in particular are comfortable with technology and often face barriers to accessing care, data on the use of digital interventions with young mothers are limited. OBJECTIVE: This study aims to examine technology access and use behavior among adolescent mothers in Lima, Peru, to inform the development of technology-mediated perinatal interventions for high-risk mothers and infants in low- and middle-income countries and other areas with limited access to care. METHODS: This mixed methods study consisted of a phone survey about technology access (N=29), focus group discussions with clinicians (N=25), and semistructured in-depth interviews with adolescent mothers (N=10) and their family members (N=8) in Lima. RESULTS: All adolescent mothers surveyed had access to a smartphone, and nearly half had access to a computer or tablet. However, participants reported a number of obstacles to consistent smartphone access related to the financial precarity of their situations. Examples of this included difficulty affording phone services, using shared plans, and losing smartphones because of theft. CONCLUSIONS: These findings indicate that adolescent mothers are connected to technology, highlighting the potential scalability of technology-based health interventions for adolescent mothers in low- and middle-income countries while identifying barriers that need to be addressed.

Effects of Plyometric Vs. Combined Plyometric Training on Vertical Jump Biomechanics in Female Basketball Players.

The purpose of this study was to assess and compare the effects of plyometric training and combined training programs on vertical jump kinematics and kinetics of female basketball players. Thirty-six female basketball players were included in the study and further divided into three groups: plyometric training, n = 11; combined training n =13; and a control group, n =12. Combined training comprised full squat exercise with low resistance (50-65% 1RM) and low volume (3-6 repetitions/set) combined with repeated jumps. Plyometric training included drop jumps and repeated jumps. Both training methods showed a moderate increase in jump performance, although combined training achieved substantially higher values than plyometric training alone. After plyometric training, the vertical velocity and displacement of the center of mass of the countermovement jump increased, while force variables decreased. Combined training increased power, vertical velocity and displacement of the center of mass, but force variables remained unchanged. Both training methods improved jump height, velocity and displacement of the center of mass. Combined training maintained force measures while plyometric training decreased them. These results indicate that combined training might provide better outcomes on jump performance than plyometric training alone. It also appears important to measure biomechanical variables to appropriately interpret the effects of different training methods.

Associations between adverse childhood experiences and migraine among teenage mothers in Peru.

OBJECTIVE: The objective of this study was to evaluate the association between (1) different types of ACEs and migraine, and (2) the number of ACEs and migraine among adolescent mothers in Lima, Peru. METHODS: Our cross-sectional study included 787 adolescent mothers (14- to 18-years of age) in Peru. In-person interviews were conducted postpartum, in hospital, within 2-days of delivery. Nine types of ACEs were assessed, including exposure to three categories of abuse, two categories of neglect, and four categories of household dysfunction. Multivariable logistic regression procedures were used to estimate odds ratios (ORs) and 95% confidence intervals (95% CI) for the association between ACEs and migraine while adjusting for putative confounders. RESULTS: Approximately 75% of adolescent mothers reported having experienced at least one type of ACE. Adolescent mothers who reported any childhood abuse had 1.49-fold increased odds of migraine (aOR = 1.49; 95% CI 1.03-2.18) compared to those with no history of childhood abuse. Adolescent mothers who reported experiencing household dysfunction had 1.56-fold increase odds of migraine (aOR = 1.56; 95% CI 1.09-2.24). Compared to participants who reported no ACE, those who experienced four or more ACEs had 3.09-fold (aOR = 3.09; 95% CI 1.80-5.40) increased odds of migraine (ptrend < 0.001). CONCLUSION: Exposure to ACEs is highly prevalent in adolescent-aged mothers postpartum and is associated with increased odds of migraine. These findings support the importance of screening for ACEs and migraine among adolescent mothers; and the need for providing culturally appropriate, trauma-informed headache care.

Psychometric properties of the Spanish version of the 10-item Connor Davidson Resilience Scale (CD-RISC) among adolescent mothers in Peru.

The objective of this research is to assess the psychometric properties of the Connor-Davidson Resilience Scale (CD-RISC) in order to contribute to the literature identifying validated resilience measures in low-resource settings where individuals face significant adversity. This cross-sectional study included 789 adolescent mothers who delivered at a maternity hospital in Lima, Peru. The Spanish version of the 10-item CD-RISC was used to measure resilience. Internal consistency and construct validity were assessed by evaluating individual item characteristics as well as the association of CD-RISC score with symptoms of depression, anxiety and sleep disturbance. Exploratory factor analysis (EFA) was performed to test the factorial structure of the CD-RISC. The CD-RISC was found to have good internal consistency (Cronbach's alpha = 0.85). CD-RISC scores were positively associated with school attendance, financial hardship, and history of childhood abuse; scores were negatively associated with household dysfunction, depression, anxiety and poor sleep quality. The results of the EFA showed that the CD-RISC contained a two-factor solution, which accounted for 46% of the variance. Overall, these findings suggest that the Spanish-language version of the CD-RISC-10 is an adequate measure of resilience in this population. Further research is needed to incorporate culturally-specific constructs into resilience measures.