Heat production during exercise in pregnancy: discerning the contribution of total body weight

Studies have reported enhanced thermoregulatory function as pregnancy progresses; however, it is unclear if differences in thermoregulation are attributed to weight gain or other physiological changes. This study aimed to determine if total body weight will influence thermoregulation (heat production (Hprod)), heart rate, and perceptual measurements in response to weight-bearing exercise during early to late pregnancy. A cross-sectional design of healthy pregnant women at different pregnancy time points (early, T1; middle, T2; late, T3) performed a 7-stage weight-bearing incremental exercise protocol. Measurements of Hprod, HR, and RPE were examined. Two experimental groups were studied: (1) weight matched and (2) non-weight matched, in T1, T2, and T3. During exercise, equivalent Hprod at T1 (326 ± 88 kJ), T2 (330 ± 43 kJ), and T3 (352 ± 52 kJ) (p = 0.504); HR (p = 0.830); and RPE (p = 0.195) were observed in the WM group at each time point. In the NWM group, Hprod (from stages 1-6 of the exercise) increased across pregnancy time points, T1 (291 ± 76 kJ) to T2 (347 ± 41 kJ) and T3 (385 ± 47 kJ) (p < 0.001). HR increased from T1 to T3 in the warm-up to stage 6 (p = 0.009). RPE did not change as pregnancy time point progressed (p = 0.309). Total body weight, irrespective of pregnancy time point, modulates Hprod and HR during exercise. Therefore, accounting for total body weight is crucial when comparing thermoregulatory function during exercise across pregnancy.

Does a history of childbirth impact injury prevalence and mental health in female military members?

The effect of parity status on the prevalence and impact of musculoskeletal injury (MSKi) among female Canadian Armed Forces (CAF) members is unknown. This study aims to identify whether a history of childbirth and pregnancy-related complications are associated with MSKi occurrence among female members of the CAF. From September 2020 to February 2021, data were collected via an online questionnaire that assessed MSKi, reproductive health, and barriers to recruitment and retention in the CAF. Actively serving, female members were included in this analysis stratified by parous (n = 313) or nulliparous (n = 435) status. Descriptive analysis and binary logistic regressions were used to identify prevalence and adjusted odds ratios (aOR) of repetitive strain injuries (RSI), acute injuries, and body regions affected. Covariates included in aOR: age, body mass index, and rank. A p value of <0.05 was considered significant and 95% confidence intervals (CI) were reported. Female members with a history of childbirth were more likely to report an RSI (80.9% vs. 69.9%, OR = 1.57, CI: 1.03 to 2.40), and when stratified by body region, were more likely to have an RSI of the wrist (30.0% vs. 20.5%, aOR = 1.62, CI: 1.09 to 2.40), and foot (39.3% vs. 24.1%, aOR = 1.79, CI: 1.24 to 2.59). When compared to the nulliparous group, parity did not influence prevalence of acute injuries. MSKi and mental health perceptions were different for females who experienced postpartum depression, miscarriage, or preterm birth. Childbirth and pregnancy-related complications impact prevalence of some RSI among female CAF members. Thus, specific health and fitness support may be needed for parous female CAF members.

Sex disparities in self-reported musculoskeletal injuries in the Canadian Armed Forces

Recent comprehensive systematic reviews indicate that females are at greater risk of musculoskeletal injuries (MSKi) than males in military populations. Considering the Canadian Armed Forces (CAF) goal of increasing female representation in the next few years, exploring these trends is essential. We aimed to determine the association between biological sex and MSKi in the CAF. An online survey was conducted with active-duty and former CAF members aged 18-65 years. Sex disparities in MSKi (acute or repetitive strain [RSI]) were analyzed using bivariate associations and binary logistic regressions with significance level at p < 0.05. Analyses were stratified by military environment (i.e., Army, Navy, and Air Force). From the 1947 respondents whose biological sex was reported, 855 were females and 1092 were males. Rates of RSI sustained by females and males while serving were 76.2% and 70.5% (p = 0.011), respectively, whereas 61.4% of females reported acute injuries compared to 63.7% of males (p = 0.346). Females were more likely to report overall RSI (adjusted odds ratio [aOR]: 1.397; 95% confidence intervals [CI]: 1.068-1.829), RSI having a greater impact on daily activities (aOR [95%CI]: 2.979 [2.093-4.239]) and greater impact on career progress/length (aOR [95%CI]: 1.448 [1.066-1.968]). Acute injuries, also more prevalent in females, were reported to have a greater impact on daily activities (aOR [95%CI]: 1.688 [1.198-2.379]). This study highlights sex disparities in MSKi prevalence and outcomes. Females within the CAF sample presented greater likelihood of reporting RSI, perceived impact of RSI on daily activities and career progress/length, and perceived impact of acute injuries on daily activities.

Characteristics Associated with Pelvic Floor Disorders among Female Canadian Armed Forces Members

OBJECTIVES

Urinary incontinence (UI) and pelvic organ prolapse (POP) are prevalent pelvic floor disorders (PFDs) among the female population. In the military environment, being a non-commissioned member (NCM), and physically demanding occupations are factors associated with higher PFD risk. This study seeks to characterize the profile of female Canadian Armed Forces (CAF) members reporting symptoms of UI and/or POP.

METHODS

Present CAF members (18-65 years) responded to an online survey. Only current members were included in the analysis. Symptoms of UI and POP were collected. Multivariate logistic regressions analyzed the relationships between PFD symptoms and associated characteristics.

RESULTS

765 active members responded to female-specific questions. The prevalence of self-reported POP and UI symptoms were 14.5% and 57.0%, respectively, with 10.6% of respondents reporting both. Advanced age (adjusted odds ratio [aOR]: 1.062, CI 1.038-1.087), a body mass index (BMI) categorized as obese (aOR: 1.909, [1.183-3.081]), parity ≥1 (e.g., aOR for 1: 2.420, [1.352-4.334]) and NCMs (aOR: 1.662, [1.144-2.414]) were factors associated with urine leakage. Parity of ≥2 (aOR: 2.351, [1.370-4.037]) compared to nulliparous and having a perception of a physically demanding job (aOR: 1.933, [1.186-3.148]) were associated with experiencing POP symptoms. Parity of ≥2 increased the odds of reporting both PFD symptoms (aOR: 5.709, [2.650-12.297]).

CONCLUSION

Parity was associated with greater odds of experiencing symptoms of UI and POP. Higher age, higher BMI, and being an NCM were associated with more symptoms of UI, and the perception of having a physically demanding role increased the likelihood of reporting POP symptoms.

SmartMoms Canada: An evaluation of a mobile app intervention to support a healthy pregnancy

BACKGROUND

There is a lack of cost-effective and readily available access to evidence-based information to manage healthy behaviours for pregnant individuals. Mobile health (mHealth) tools offer a cost-effective, interactive, personalized option that can be delivered anywhere at a time most convenient for the user. This study protocol was primarily developed to, i) assess the feasibility of the SmartMoms Canada intervention in supporting participants to achieve gestational weight gain (GWG) guidelines. The secondary objectives are to, ii) assess user experience with the app, measured by adherence to the program via app software metrics and frequency of use, iii) determine the impact of SmartMoms Canada app usage on the adoption of healthful behaviours related to nutrition, physical activity and sleep habits, improvements in health-related quality of life, pregnancy-related complications, and symptoms of depression, and iv) investigate the potential extended effects of the app on postpartum health-related outcomes.

METHODS

This is a feasibility trial. Pregnant individuals aged 18-40 years with pre-gravid body mass index between 18.5 and 39.9 kg/m², carrying a singleton fetus, having Wi-Fi access, and at ≤20 weeks' gestation will be recruited. Eligible people will be followed from recruitment until 12 months postpartum.

DISCUSSION

SmartMoms Canada is the first bilingual Canadian-centric app designed for pregnant people. This mHealth intervention, with its ability to supply frequent interactions, provides pregnancy- related health knowledge to users, potentially leading to an improvement in pregnancy-related outcomes and behaviours, and, ultimately a reduction in the present economic burden related to in-person interventions.

TRIAL REGISTRATION

ISRCTN, ISRCTN16254958. Registered 20 December 2019, http://www.isrctn.com/ ISRCTN16254958.

Association Between Reproductive Health Factors and Musculoskeletal Injuries in Female Canadian Armed Forces Members

Background: Musculoskeletal injuries (MSKi) play a role in member retention in the military. In general, female military members have higher rates of MSKi than males and female reproductive health characteristics may be contributing to these disparities. This study seeks to characterize reproductive health factors in female Canadian Armed Forces (CAF) members and their relationship with MSKi. Materials and Methods: An electronic survey (SurveyMonkey^®) was made available to present and former CAF members 18-65 years of age. Responses were collected between September 2020 and February 2021. Seven female reproductive characteristics were assessed: age of menarche, menstrual cycle regularity, birth control use, having given birth while serving, endometriosis, early menopause, and secondary oligomenorrhea/amenorrhea. Binary logistic regressions were used to analyze associations between reproductive characteristics with repetitive strain (RSI) and acute injuries. Results: A total of 2,001 participants consented to the survey with 855 respondents being female. Females reporting menstrual cycles as never regular, irregular for a few months, who never had a period, and whose periods stopped while serving presented a greater likelihood of reporting RSI compared to their peers who reported regular menstrual cycles (adjusted odds ratio [aOR]: 1.898, confidence interval [CI]: 1.138-3.166). Participants who have experienced endometriosis presented a higher likelihood of reporting acute injuries than those who did not (aOR: 2.426, CI: 1.030-5.709). Conclusion: This examination of females within the CAF suggests that irregular menstrual cycles or absent periods increase the likelihood of experiencing MSKi, namely those categorized as RSI injuries and reporting endometriosis were associated with greater rates of acute injuries.

Physical Activity and Weight Gain Throughout Pregnancy Are Associated With Umbilical Cord Markers

OBJECTIVE

Maternal serum and umbilical cord (UC) lipid and glucose levels are influenced by a variety of maternal factors over the course of pregnancy, including maternal physical activity (PA) levels and gestational weight gain (GWG). However, previous research has not assessed the interaction of these 2 variables. This study investigated mid-gestation (24-28 weeks) and late gestation (34-38 weeks) maternal and UC serum lipid and glucose profiles in relation to maternal PA status and GWG, independently and in combination.

METHODS

This study had a longitudinal design. Pregnant participants (n = 40) were categorized as active or inactive based on the 2019 Canadian Guideline for Physical Activity throughout Pregnancy, and GWG was categorized as insufficient, appropriate, or excessive based on 2009 Institute of Medicine recommendations. Fasting maternal serum was taken in mid- and late gestation, and venous UC serum was taken at birth.

RESULTS

No relationship was found between maternal serum values and PA and/or GWG. Infants born to individuals who were physically active across pregnancy, or who were active in mid-pregnancy and had their activity status drop in late gestation, had lower UC total cholesterol levels than those who were inactive throughout pregnancy (P < 0.0001). Participants who had gained weight appropriately at mid-gestation had significantly lower UC glucose levels than those who gained weight insufficiently (P = 0.040) or excessively (P = 0.021).

CONCLUSION

In our study, PA, and GWG (independently and in combination) may not have affected maternal serum; however, meeting PA recommendations at mid-gestation may provide prophylactic effects on UC serum, potentially providing long-term health benefits to the newborn.

Population characteristics associated with adherence to prenatal group-based exercise programs

Community-based supervised group exercise may be an effective option to increase activity levels throughout pregnancy. Previous studies that have explored predictors of low adherence to exercise during pregnancy have not examined group-based settings. We analysed an international cohort of 347 pregnant women who participated in group-based prenatal exercise interventions (from <20 weeks to 34-36 weeks pregnant). Probable adherence predictors informed by previous literature that were assessed included: pre-pregnancy physical activity level and body mass index (BMI) classification, age, number of previous pregnancies, and education level. Adherence was measured by attendance. Adjusted odds ratios (aOR) and 95% confidence intervals (CI) were calculated to explore the relationship between the selected predictors and high adherence (≥70%). Post-secondary education level versus only secondary (aOR 5.28; CI 1.67; 16.72) or primary level (aOR 13.82; CI 4.30; 44.45) presented greater likelihood to have high adherence to the exercise intervention than low adherence. Future research and public health initiatives should consider implementing strategies to overcome education-related barriers to improve accessibility to prenatal exercise.

Exploring weight bias internalization in pregnancy

Background

Recent research has shown that pregnant individuals experience weight stigma throughout gestation, including negative comments and judgement associated with gestational weight gain (GWG). Weight bias internalization (WBI) is often a result of exposure to weight stigma and is detrimental to biopsychological health outcomes. The purpose of this study was to explore WBI in pregnancy and compare scores based on maternal weight-related factors including pre-pregnancy body mass index (BMI), obesity diagnosis and excessive GWG.

Methods

Pregnant individuals in Canada and USA completed a modified version of the Adult Weight Bias Internalization Scale. Self-reported pre-pregnancy height and weight were collected to calculate and classify pre-pregnancy BMI. Current weight was also reported to calculate GWG, which was then classified as excessive or not based on Institute of Medicine (2009) guidelines. Participants indicated if they were diagnosed with obesity by a healthcare provider. Inferential analyses were performed comparing WBI scores according to pre-pregnancy BMI, excessive GWG, and obesity diagnosis. Significance was accepted as p < 0.05 and effect sizes accompanied all analyses.

Result

336 pregnant individuals completed the survey, with an average WBI score of 3.9 ± 1.2. WBI was higher among those who had a pre-pregnancy BMI of obese than normal weight (p = 0.04, η² = 0.03), diagnosed with obesity than not diagnosed (p < 0.001, Cohen’s d = 1.3), and gained excessively versus not (p < 0.001, Cohen’s d = 1.2).

Conclusions

Pregnant individuals who have a higher BMI, obesity and gain excessively may experience WBI. Given that weight stigma frequently occurs in pregnancy, effective person-oriented strategies are needed to mitigate stigma and prevent and care for WBI.

Adaptation of Anaerobic Field-Based Tests for Wheelchair Basketball Athletes

Purpose: The aim of this study was to propose field-based tests to estimate the anaerobic power of wheelchair basketball athletes. Methods: Eleven lower class wheelchair basketball players performed the Wingate test (WT) and two field-based tests (repeated sprints) of 15 (S-15) and 20 (S-20) meters. The WT provides data in Watts (W). The S-15 and S-20 are recorded in seconds and converted to W using the Running-based Anaerobic Sprint Test (RAST) equation. The participants also completed other field-based tests, such as right and left handgrip strength (HGS) tests and the medicine ball chest pass test. In addition, body mass and height were measured, and the body composition was estimated. The field-based tests and anthropometric measures were used to estimate WT peak power (PP) and mean power (MP) using multiple linear regressions. Results: The field-based tests underestimated the anaerobic power measured with the WT (in W). However, a linear regression model based on S-15 PP, right HGS, height, and body mass explained 76% (P= .040) of the WT PP variance. Another model based on S-15 MP and right HGS explained 72% (P= .006) of the WT MP variance. Both models had excellent reliability (ICC > 0.90). Conclusion: WT PP can be estimated using S-15 PP (W), right HGS, height, and body mass. The WT MP is predicted using S-15 MP (W) and right HGS. Therefore, a combination of field-based tests and anthropometric measures seem to be appropriate to determine anaerobic power of lower class wheelchair basketball athletes.

Weight stigma and prenatal physical activity: Exploring the perspectives of pregnant women living with obesity

OBJECTIVE

To identify sources of weight stigma in physical activity (PA)-related milieus reported by pregnant women living with obesity. We also report person-informed strategies to improve the delivery of PA promotions and prescriptions to prevent weight stigma and improve maternal PA.

DESIGN

This is a qualitative descriptive study and semi-structured interviews were conducted.

SETTING AND PARTICIPANTS

Purposive sampling including pregnant women living with obesity, with a body mass index ≥35.0 kg/m², ≥18 years of age, and receiving specialized prenatal care were recruited from an obstetrics clinic in Kingston, Canada.

MEASUREMENT AND FINDINGS

Data were assessed by a content analysis, whereby coded themes represented sources of weight stigma related to prenatal PA. Demographic characteristics (pre-pregnancy body mass index, age, gestational age) were summarized and presented as means and standard deviations. In-depth interview data were collected from eight women. Average pre-pregnancy BMI, age, and gestational age were 44.6±4.8 kg/m², 32.0±4.1 years, 31.1±5.8 weeks, respectively. Two sources of weight stigma related to prenatal PA were identified: 1. Lack of visual representation - online images and images found in exercise promotional material do not include women who have obesity; 2. Lack of individualized recommendations - currently available prenatal PA guidelines and/or recommendations from healthcare providers do not always consider individual physical barriers or health goals women may have.

KEY CONCLUSION AND IMPLICATIONS FOR PRACTICE

By increasing body positive representation of pregnant women exercising and offering person-centered prenatal PA recommendations, maternal PA may improve including women living with obesity. Findings from this work can inform future PA interventions, health promotion programming, and prescriptions from prenatal care providers to implement person-oriented strategies to prevent weight stigma and improve the delivery of care for pregnant women living with obesity.

Evaluation of Afterschool Activity Programs' (ASAP) Effect on Children's Physical Activity, Physical Health, and Fundamental Movement Skills

Background

Physical literacy-focused afterschool activity programs (ASAPs) can be an effective strategy to improve children’s health-related parameters. We sought to compare physical activity, body composition, aerobic capacity, and fundamental movement skills between physical literacy-focused ASAP and a standard recreational ASAP.

Method

A pre–post (6 months) comparison study was conducted in 5- to 12-year-old children in a physical literacy-focused ASAP (physical literacy group, n = 14) and children attending a standard recreational ASAP (comparison group, n = 15). Physical activity guideline adherence was assessed using accelerometry, body composition was analyzed using bioelectrical impedance, aerobic capacity was estimated using the Progressive Aerobic Cardiovascular Endurance Run test, and fundamental movement skills were evaluated using the Test of Gross Motor Development–2.

Results

There were no significant differences between groups at baseline. After 6 months, the physical literacy group exhibited a significant improvement in their total raw score for the Test of Gross Motor Development–2 (p = .016), which was likely due to improvements in object control skills (p = .024). The comparison group significantly increased body mass index (p = .001) and body fat (p = .009) over time. No significant between-group differences were found; however, there was a trend for improved aerobic capacity in the physical literacy group (d = 0.58).

Conclusions

Engagement in the physical literacy-focused ASAP contributed to an attenuated increase in adiposity and an improvement in object control skills.

Musculoskeletal Injuries Among Females in the Military: A Scoping Review

INTRODUCTION

Musculoskeletal injuries (MSKi) are a common challenge for those in military careers. Compared to their male peers, reports indicate that female military members and recruits are at greater risk of suffering MSKi during training and deployment. The objectives of this study were to identify the types and causes of MSKi among female military personnel and to explore the various risk factors associated with MSKi.

MATERIALS AND METHODS

A scoping review was conducted over a 4-month time frame of English language, peer-reviewed studies published from 1946 to 2019. Search strategies for major biomedical databases (e.g., MEDLINE; Embase Classic + Embase; and the following EBM Reviews-Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, Database of Abstracts of Reviews of Effects, Health Technology Assessment, and the NHS Economic Evaluation Database) were developed by a senior medical information specialist and included 2,891 titles/abstracts. Study selection and data collection were designed according to the Population, Concept, and Context framework. Studies were included if the study population provided stratified data for females in a military context.

RESULTS

From a total of 2,287 citations captured from the literature searches, 168 peer-reviewed publications (144 unique studies) were eligible for inclusion. Studies were identified from across 10 countries and published between 1977 and 2019. Study designs were primarily prospective and retrospective cohorts. Most studies assessed both prevalence/incidence and risk factors for MSKi (62.50%), with few studies assessing cause (13.69%). For MSKi of female recruits compared to active female members, the prevalence was higher (19.7%-58.3% vs. 5.5%-56.6%), but the incidence (0.02%-57.7% vs. 13.5%-71.9%) was lower. The incidence of stress fractures was found to be much higher in female recruits than in active members (1.6%-23.9% vs. 2.7%). For anthropometric risk factors, increased body fat was a predictor of MSKi, but not stress fractures. For physiological risk factors for both female military groups, being less physically fit, later menarche, and having no/irregular menses were predictors of MSKi and stress fractures. For biomechanical risk factors, among female recruits, longer tibial length and femoral neck diameter increased the risk of stress fractures, and low foot arch increased risk of an ankle sprain. For female active military members, differences in shoulder rotation and bone strength were associated with risk of MSKi. For biological sex, being female compared to male was associated with an increased risk of MSKi, stress fractures, and general injuries. The consequences of experiencing MSKi for active military included limited duties, time off, and discharge. For recruits, these included missed training days, limited duty days, and release.

CONCLUSIONS

This scoping review provides insight into the current state of the evidence regarding the types and causes of MSKi, as well as the factors that influence MSKi among females in the military. Future research endeavors should focus on randomized controlled trials examining training paradigms to see if women are more susceptible. The data presented in the scoping review could potentially be used to develop training strategies to mitigate some of the identified barriers that negatively impact women from pursuing careers in the military.

Women's Suggestions for How To Reduce Weight Stigma in Prenatal Clinical Settings

OBJECTIVE

To describe the experiences of weight stigma in prenatal clinical settings among high-risk pregnant women living with obesity and to obtain women's perspectives regarding changes to prenatal health care practices that may reduce weight stigma.

DESIGN

Qualitative descriptive study.

SETTING/LOCAL PROBLEM

High-risk obstetrics clinic. Weight stigma experienced in prenatal clinical settings can negatively influence maternal health and well-being as well as communication with health care providers.

PARTICIPANTS

Nine pregnant women with obesity who were receiving specialized prenatal care in their third trimester.

INTERVENTION/MEASUREMENTS

Women participated in semistructured telephone interviews. Data were inductively analyzed using a content analysis, whereby coded data were organized to represent experiences of or suggestions provided by pregnant women to reduce weight stigma in prenatal clinical settings.

RESULTS

Experiences of weight stigma included poor communication, generalizations made about health and lifestyle behaviors, and focusing only on excess body weight during clinical appointments as the cause of negative health outcomes. To reduce weight stigma, women suggested that health care providers practice sensitive communication, offer individualized care for weight management, and reduce the focus on body weight by also independently addressing comorbidities or other health indicators.

CONCLUSION

Women interviewed for this study provided suggestions that can be implemented in prenatal clinical settings to reduce weight stigma and improve the delivery of equitable health care.

Taking a patient-oriented approach in exercise interventions for pregnant women: a commentary

Taking a patient-oriented approach to developing lifestyle interventions includes incorporating the patient into the program's design, delivery, and evaluation. This commentary assumes that a patient-oriented approach has not yet been implemented and tested in exercise-based interventions designed for pregnant women. We outline and define a patient-oriented approach to conduct exercise-based research and review previous physical activity interventions designed for pregnant women to determine whether a patient-oriented approach was applied. In addition, pregnant women living with obesity may have unique barriers to engaging in prenatal exercise interventions that have not been previously addressed, such as having experienced weight stigma before pregnancy in healthcare and fitness settings. We propose suggestions for future trials to effectively take a patient-oriented approach when designing and implementing prenatal exercise interventions to address patient-informed barriers and incorporate suggested facilitators for physical activity. Given that prenatal activity levels are low and pregnant women may have unique barriers to engaging in exercise interventions, a patient-oriented approach may be an effective strategy to improve inclusivity and equity and, as a result, increase uptake and adherence to the intervention.

Eating Habits, Advice from Family/Friends, and Limited Personal Effort May Increase the Likelihood of Gaining Outside Gestational Weight Gain Recommendations

OBJECTIVES

The present study analyzed the association between (i) eating habits during pregnancy, (ii) advice from family or friends about gestational weight gain (GWG), and iii) personal effort to stay within weight gain limits, and meeting GWG recommendations.

METHODS

Participants included pregnant and postpartum women who completed the validated electronic maternal health survey (EMat). Sociodemographic, lifestyle variables, and body mass index were covariates used in the analyses.

RESULTS

Among all eligible women (1171), and a subset of women receiving a specific GWG target from HCP (365, 31.2%), participants who considered that their eating habits became less healthy, or could not evaluate if habits changed, had a higher likelihood of gaining above (adjusted odds ratio, aOR = 2.62; 95% CI 1.84; 3.73 for the total sample (TS); aOR = 4.79; CI 2.32;9.88 for the subset) GWG guidelines after adjusting for the covariates. Women who received advice from family or friends about how much weight they should gain while pregnant were more likely to experience GWG below (TS: aOR = 1.49; CI 1.02;2.17; subset: aOR = 1.95; CI 1.03;3.68) and above (TS: aOR = 1.42; CI 1.01;1.99; subset: aOR = 1.92; CI 1.06;3.48) guidelines, when compared to women who did not receive family/friends advice. Moreover, lower personal effort to stay within weight gain limits was associated with gaining below (TS: aOR = 1.77; CI 1.07;2.92; subset: aOR = 2.71; CI 1.30; 5.65) GWG guidelines.

CONCLUSIONS FOR PRACTICE

Women self-reporting less healthy eating habits than before pregnancy, receiving advice from family/friends about GWG, and lower personal effort to stay within guidelines, had an increased odds of weight gain discordant with recommendations.

Physical activity and gestational weight gain predict physiological and perceptual responses to exercise during pregnancy

BACKGROUND

Exercise is known to improve the health of the pregnant woman and her child. Studies that have evaluated physiological parameters during prenatal exercise have conflicting results. Better understanding of these physiological responses can modify exercise prescriptions, safety, and monitoring strategies. We examined the association between age, prepregnancy body mass index (BMI), gestational weight gain (GWG), and physical activity (PA) levels, factors that may influence a change in physiological (HR, VO₂ responses) and perceptual (RPE) responses to acute exercise throughout pregnancy.

METHODS

Twenty-two healthy pregnant women (31.4 ± 3.7 years) performed a Submaximal incremental Walking Exercise Test (SWET). Early- (13-18 weeks), mid- (24-28 weeks), and late-pregnancy (34-37 weeks) were compared. VO₂ (L/min; ml/kg/min), HR (bpm), and RPE were collected at the end of each test stage. PA was determined by accelerometry. We associated PA levels, GWG, prepregnancy BMI, and age with HR, RPE, and VO₂ responses.

RESULTS

HR, RPE, and absolute VO₂ were higher in late-pregnancy compared to earlier time points (p < .05; η² = 0.299-0.525). Regression models were built for HR (all time points), RPE (early- and late-pregnancy), and VO₂ (L/min; late-pregnancy). HR (late-pregnancy) was predicted by time in vigorous PA, GWG, age, and prepregnancy BMI (r² = 0.645; SEE = 5.84). RPE (late-pregnancy) was predicted by sedentary time, GWG, prepregnancy BMI, and age (r² = 0.662; SEE = 1.21).

CONCLUSION

Physiological/perceptual responses were higher in late-pregnancy compared to other time points and associated with combined PA, GWG, prepregnancy BMI, and age. These findings can be used to modify exercise prescriptions and designs for future PA interventions in pregnant women.

Physical activity may be an adjuvant treatment option for substance use disorders during pregnancy: A scoping review

BACKGROUND

Substance abuse in pregnancy increases the chance of physical and neurobehavioral disabilities as well as many other undesirable fetal outcomes. In nonpregnant populations, physical exercise has shown to be an effective adjunctive therapy option for substance use disorders. Given the known positive maternal and fetal physiological and mental health benefits associated with prenatal exercise, perhaps exercise during pregnancy may also be a viable adjuvant therapy option for women with substance use disorders. The purpose of this scoping review was to summarize the available literature that has assessed the relationship between prenatal exercise and substance use disorders.

METHODS

A search strategy was developed combining the terms pregnancy, exercise/physical activity, and substance use. A systematic search was completed in the following databases: Medline/PubMed, SPORTDiscus, and ProQuest. Substances eligible for inclusion included illicit drugs, alcohol, and cannabis. Retrieved data were categorized as animal or human model studies, and were summarized narratively.

RESULTS

Eight studies were included in this review (five human studies, three animal model studies). Studies in humans suggest that pregnant women with substance use disorders are interested in engaging in physical activity interventions; however, known acute metabolic and physiological responses to prenatal exercise may be impaired in this population. Rodent models show preliminary evidence for improved mental health outcomes following prenatal exercise for substance use disorders.

CONCLUSION

The findings from this review may inform the development of future clinical trials to test the effect of structured exercise programs as an adjunctive treatment option for pregnant women with substance use disorders.

Endurance Running Training Individually Guided by HRV in Untrained Women

da Silva, DF, Ferraro, ZM, Adamo, KB, and Machado, FA. Endurance running training individually guided by HRV in untrained women. J Strength Cond Res 33(3): 736-746, 2019-The aim of this study was to analyze the effects of heart rate variability (HRV)-guided training compared with a standardized prescription on (a) time to complete 5-km running performance (t5km), (b) peak treadmill running speed (Vpeak) and its time limit (tlim at Vpeak), and (c) autonomic cardiac modulation (i.e., parasympathetic activity and recovery) in untrained women. Additionally, we correlated changes in t5km with changes in Vpeak, tlim at Vpeak and autonomic cardiac modulation. Thirty-six untrained women were divided into a HRV-guided training group (HRVG) and a control group (CG). The CG followed a predefined program, alternating moderate-intensity continuous training (MICT) and high-intensity interval training (HIIT). The determination of MICT or HIIT was based on the pretraining HRV for HRVG. MICT was performed if HRV was <mean - 1 SD of previous measures. Otherwise, HIIT was prescribed. The t5km, Vpeak, tlim at Vpeak, parasympathetic activity (i.e., rMSSD) and parasympathetic reactivation (i.e., HRR) were measured before and after the training period. The t5km decreased to a greater magnitude in the HRVG (-17.5 ± 5.6% vs. -14 ± 4.7%; Effect Size (ES) between-group difference = moderate). rMSSD and tlim at Vpeak only improved in HRVG (+23.3 ± 27.8% and +23.6 ± 31.9%, respectively). The HRVG experienced greater improvements in Vpeak and HRR (Vpeak: 10 ± 7.3% vs. 8.2 ± 4.7%; HRR: 19.1 ± 28.1% vs. 12.6 ± 12.9%; ES between-group difference = small). Although HRVG performed less MICT than CG, the volume of MICT was negatively related to changes in t5km. Vpeak changes were highly correlated with t5km changes. The greater improvements in HRVG for t5km and autonomic modulation reinforce the potential application of this tool.

Peak velocity and its time limit are as good as the velocity associated with VO 2max for training prescription in runners

This study compared the effects of 4 weeks of training prescribed by peak velocity (V _peak ) or velocity associated with maximum oxygen uptake (vVO _2max ) in moderately trained endurance runners. Study participants were 14 runners (18–35 years) randomized into 2 groups, named group VO ₂ (GVO ₂ ) and group V _peak (GVP). The GVO ₂ had training prescribed by vVO _2max and its time limit (t _lim ), whereas the GVP had training prescribed by V _peak and its t _lim . Four tests were performed on a treadmill: 2 maximum incremental for V _peak and vVO _2max and 2 for their t _lim . Performance (10 km) was evaluated on a 400 m track. Evaluations were repeated after 4 weeks of endurance training. The results showed a significant effect of training on V _peak [GVP (16.7±1.2 – 17.6±1.5 km ^. h ⁻¹ ), GVO ₂ (17.1±1.9–17.7±1.6 km·h ⁻¹ )]; vVO _2max [GVP (16.4±1.4–17.0±1.3 km·h ⁻¹ ), GVO ₂ (17.2±1.7–17.5±1.9 km·h ⁻¹ )]; and 10 km performance [GVP (41.3±2.4–39.9±2.7 min), GVO ₂ (40.1±3.4–39.2±2.9 min)]. The V _peak highly correlated with performance in both pre- and post-training in GVP (–0.97;–0.86) and GVO ₂ (–0.95;–0.94), as well as with vVO _2max in GVP (–0.82;–0.88) and GVO ₂ (–0.99; –0.98). It is concluded that training prescribed by V _peak promoted similar improvements compared to training prescribed by vVO _2max . The use of V _peak is recommended due to its practical application and the low cost of determination.

The effects of culture on guideline discordant gestational weight gain: a systematic review protocol

BACKGROUND

A significant proportion of women exceeds or does not meet the Institute of Medicine's gestational weight gain (GWG) guidelines. Inadequate, excessive GWG or weight loss during pregnancy is associated with an increased risk of negative maternal and fetal outcomes. Among the many determinants of GWG identified in the 2009 Institute of Medicine guidelines, culture was named as one of the few whose influence has not been fully explored. Some cultural beliefs may erroneously promote overeating as "eating for two" and discourage physical activity during pregnancy, but there is lack of empirical evidence on how culture affects GWG. The purpose of this systematic review is to examine the effects of culture on GWG.

METHODS/DESIGN

Ten electronic databases will be searched to identify studies reporting on the effects of culture on GWG. Grey literature, published conference abstracts, websites of relevant organizations and reference lists of included studies will also be searched. Studies that report on effects of culture, acculturation, ethnicity, race, nationality, ancestry and identity on GWG in adult women will be included. Quality of evidence will be evaluated using the grading of recommendations, assessment, development and evaluations (GRADE) approach to rating evidence. Study selection, data extraction and risk of bias assessment will be conducted by two independent reviewers, with disagreements being resolved by consensus or third party adjudication as needed. Formal meta-analyses will be conducted among included studies that are sufficiently statistically and clinically homogeneous.

DISCUSSION

This review will provide a comprehensive assessment and synthesis of current evidence and will draw attention to potential gaps where future research on the effects of culture on guideline discordant gestational weight gain remains to be conducted.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42015023399.

Physiological and Technical-tactical Analysis in Brazilian Jiu-jitsu Competition

Purpose

The present study aims at investigating the physiological response and technical-tactical parameters in Brazilian jiu-jitsu competition.

Methods

The study included 35 male Brazilian jiu-jitsu athletes (adult category, body mass: 80.2 ± 13.0 kg), graded from white to brown belt, during combats fought at regional level. Twenty-two fights were analyzed in terms of technique and time structure. Blood glucose, lactate and maximal isometric grip strength were determined before and after the fights. The rate of perceived exertion was also assessed after the fight, using the 6-20 Borg rating. The fights were recorded and the following variables were determined: the exertion/pause ratio and subjective intensity of actions, categorized between low and high intensity.

Results

The results indicated that during Brazilian jiu-jitsu fights, the glycolytic pathway is only moderately activated (lactate before: 4.4 (4.0 – 4.6) mmol/L, after: 10.1 (8.0 – 11.3) mmol/L; glucose before: 112.4 ± 22.3 mg/dL, after: 130.5 ± 31.0 mg/dL). The exertion during the fight resulted in significant reductions in handgrip strength (right hand grip before: 45.9 ± 10.3 kgf, after: 40.1 ± 9.5 kgf; left hand grip before: 44.2 ± 11.1 kgf, after: 37.0 ± 10.2 kgf). The athletes rated the fight as hard: 15 (13 – 15). Effort/pause ratio was 6:1, while high-intensity actions lasted approximately 4 s, resulting in a low/high intensity? ratio of 8:1.

Conclusion

It is recommended that coaches direct the training loads to simulate the energy demand imposed by the competitive matches, activating moderately the glycolytic pathway. Moreover, the time structure of combats can be used to prescribe both physical and technical-tactical training.

Incremental test design, peak 'aerobic' running speed and endurance performance in runners

OBJECTIVES

Peak running speed obtained during an incremental treadmill test (Vpeak) is a good predictor of endurance run performance. However, the best-designed protocol for Vpeak determination and the best Vpeak definition remain unknown. Therefore, this study examined the influence of stage duration and Vpeak definition on the relationship between Vpeak and endurance run performance.

DESIGN

Relationship.

METHODS

Twenty-seven male, recreational, endurance-trained runners (10-km running pace: 10-17 k mh(-1)) performed, in counterbalanced order, three continuous incremental treadmill tests of different stage durations (1-, 2-, or 3-min) to determine Vpeak, and two 5-km and two 10-km time trials on a 400-m track to obtain their 5-km and 10-km run performances. Vpeak was defined as either (a) the highest speed that could be maintained for a complete minute (Vpeak-60 s), (b) the speed of the last complete stage (Vpeak-C), or (c) the speed of the last complete stage added to the multiplication of the speed increment by the completed fraction of the incomplete stage (Vpeak-P).

RESULTS

The Vpeak determined during the 3-min stage duration protocol was the most highly correlated with both the 5-km (r=0.95) and 10-km (r=0.92) running performances and these relationships were minimally influenced by the Vpeak definition. However, independent of the stage duration, the Vpeak-P provided the highest correlation with both running performances.

CONCLUSIONS

Incremental treadmill tests comprising 3-min stage duration is preferred to 1-min and 2-min stage duration protocols in order to determine Vpeak to accurately predict 5-km and 10-km running performances. Further, Vpeak-P should be used as standard for the determination of Vpeak.

Effect of stage duration on maximal heart rate and post-exercise blood lactate concentration during incremental treadmill tests

OBJECTIVES

This study compared the responses during maximal incremental treadmill tests of 1-min, 2-min, and 3-min stage durations mainly in terms of maximal heart rate (HRmax) and peak blood lactate concentration (LApeak).

DESIGN

Repeated-measures.

METHODS

Thirty-four male, recreational, endurance-trained runners (40±13 years) performed three tests on a motorized treadmill. The tests started at 8kmh(-1) with increments of 1kmh(-1) every 1min for the short-stage protocol, every 2min for the intermediate-stage protocol, and every 3min for the long-stage protocol. LApeak was defined for each subject as the highest value among the lactate concentrations determined at the end of each test and at the third, fifth and seventh minutes after test, during passive recovery.

RESULTS

Analysis of variance revealed a significant effect of the stage duration on the HRmax (p=0.003) and LApeak (p=0.001). The HRmax was higher in the intermediate-stage compared to the short-stage protocol (184.8±12.7 vs. 181.8±12.1beatsmin(-1), p<0.001), but no significant differences were found between the long-stage (183.1±12.1beatsmin(-1)) and the intermediate-stage or short-stage protocols (p>0.05). The LApeak was lower in the long-stage compared to the short-stage and intermediate-stage protocols (7.9±2.2 vs. 9.4±2.2 and 9.2±1.9mmolL(-1), respectively, p<0.05). Further, blood lactate reached peak concentration at the fifth minute after test for all the protocols.

CONCLUSIONS

Thus, HRmax and LApeak depend on the stage duration of the incremental test, but the moment at which blood lactate reaches peak concentration is independent of the duration. Further, we suggest 2-min stage duration protocols to determine HRmax.