How do sleepwear and bedding fibre types affect sleep quality: A systematic review.

Sleepwear and bedding materials can affect sleep quality by influencing the skin and body temperature and thermal comfort. This review systematically evaluates the impact of sleepwear or bedding of different fibre types on sleep quality. A systematic search was conducted in six data bases plus Google Scholar and manual searches. Original articles that compared human sleep quality between at least two fibre types of bedding or sleepwear were included, resulting in nine eligible articles included in the review. The fibre types included cotton, polyester, wool, and blended materials for sleepwear; cotton, duck down, goose down, polyester and wool for duvet; and linen and a combination of cotton and polyester for bedding. The interplay between fibre materials and sleep quality is complex. Blended sleepwear demonstrated potential benefits for specific populations. Wool sleepwear showed benefits for sleep onset in adults (cool conditions) and in older adults (warm conditions). Linen bedsheets improved sleep quality under warm conditions in young adults. Goose down-filled duvets increased slow-wave sleep under cool conditions in young adults. However, a systematic comparison of fibre types is challenging due to the diverse nature of the studies evaluating sleep quality. Further research employing standardised methodologies with standard fibre samples in different populations and in different temperature conditions is imperative to elucidate comprehensively the effects of fibre choices on sleep quality. Despite the limitations and heterogeneity of the included studies, this analysis offers valuable insights for individuals seeking to optimise their sleep experiences and for manufacturers developing sleep-related products.

A Qualitative Exploration Of Experiences And Perceptions In Recent Parents Screening Positive For Perinatal Depression In Karachi, Pakistan.

The narrative review was planned to qualitatively analyse the experiences, factors and context of parents screening positive for perinatal depression in Karachi. Semi structured in-depth interviews were conducted to explore the experiences and perceptions of participants during pregnancy, birth and 10-12 weeks after birth. Seven men and 20 women participated in the in-depth interviews. Factors in the perinatal period that affected new parents included sleep disturbances, emotional stressors linked to preference for a male child, a lack of social support, financial burdens of perinatal care, personal frustrations caused by an inability to comprehend the signs and symptoms of perinatal depression, denial to admit challenging issues concerning mental health and social disapproval with expressing mental health issues. There is an imminent need for appropriate initiatives to raise awareness about perinatal depression, and the provision of adequate perinatal mental health services for Pakistani women and men.

Risk factors of paternal postnatal depression in Pakistan: Findings from an urban sample.

Paternal postnatal depression is an emerging public health concern, with negative outcomes for men, their partners, and the newborn. There is a dearth of data on paternal postnatal depression in lower-middle-income countries like Pakistan. This study aimed to identify risk factors of postnatal depression in Pakistani men. Men who consented to this cross-sectional study completed a questionnaire that included sociodemographic information and Urdu translated versions of the Edinburgh Postnatal Depression Scale (EPDS) and the Pittsburgh Sleep Quality Index, 10-12 weeks postpartum. Descriptive analyses for the sociodemographic variables were calculated. Univariate analyses were conducted to calculate the relative risk and 95% confidence interval of the independent variables with an EPDS score of >10. Multivariate binary logistic regression models were performed for risk factors of paternal postnatal depression. Fifty-one questionnaires were analyzed and 23.5% of the participants scored more than 10 on the EPDS. Spouse's EPDS score > 12, and own sleep disturbance were risk factors of paternal postnatal depression in Pakistani men. There is an imminent need to incorporate fathers in the existing and future perinatal mental health programs in Pakistan.

Perinatal depression in Pakistan: A systematic review and meta-analysis.

OBJECTIVE: To estimate the prevalence and associated risk factors of perinatal depression in Pakistan. METHODS: We conducted a systematic search of Medline, PsycINFO, CINAHL, EMBASE, and Global health, up through May 31, 2019. Studies reporting on the prevalence of perinatal depression in Pakistan with or without associated risks factors were included. RESULTS: Forty-three studies reporting data from 17 544 women met the eligibility criteria and were included. Overall, the pooled prevalence of antenatal depression was 37% (95% CI: 30-44), while that of postnatal depression was 30% (95% CI: 25-36). The prevalence of perinatal depression in women residing in urban areas and those living in rural settings was not significantly different. The most frequently reported risk factors for antenatal depression were intimate partner violence and poor relationship with spouse, and that reported for postnatal depression was low-income level. An unintended pregnancy was significantly associated with perinatal depression in Pakistan. CONCLUSIONS: We identified variability in prevalence rate of perinatal depression in Pakistan. It is difficult to gauge the true magnitude of this problem potentially due to differing risk factors between the antenatal and postnatal periods and the lack of uniformity of data collection protocols and procedures. The high prevalence rates of 30%-37% compared to global estimates suggest policy makers and stakeholders should direct additional resources toward improving perinatal mental health in Pakistan.

Cognitive effects of video games in older adults and their moderators: a systematic review with meta-analysis and meta-regression.

The growing interest in preserving cognition through video games in the ageing population is evidenced by its wealth of literature. However, there has been a lack of consensus on video games efficacy and even limited understanding on the factors moderating its effectiveness. The present review sought to evaluate video game effects, relative to no-game control condition, on cognitive functions in older adults. The functions included processing speed, attention, delayed memory, reasoning, and executive functions (inhibition, shifting and updating memory). Personal and methodological moderators were explored to explain the variability in cognitive effects using meta-regression. Through a systematic literature search of online databases, 27 intervention studies were eligible, with a total of 1126 participants, for analysis. Using random-effect models, small but significant training effects were found on updating memory but none were detected in other cognitive functions. The heterogeneity across studies was in general high for all cognitive functions and was partially accounted for, in all cognitive functions except for inhibition and updating, by different moderators such as the proportion of females, outcome measure parameters, training intensity, and game type. The findings highlight limited effects of video games on cognitive functions that were largely influenced by factors related to study design.

Hyperventilation-Aided Recovery for Extra Repetitions on Bench Press and Leg Press.

Sakamoto, A, Naito, H, and Chow, CM. Hyperventilation-aided recovery for extra repetitions on bench press and leg press. J Strength Cond Res 34(5): 1274-1284, 2020-Hyperventilation (HV)-induced alkalosis, an ergogenic strategy, improved repeated pedaling sprint performance through enhanced H removal. However, it did not confer beneficial effects on other forms of exercises. This study investigated the benefits of HV-aided recovery on lifting repetitions and joint velocity during resistance training involving multiple joints and both concentric and eccentric contractions. Eleven power-trained men (mean ± SD age: 22.5 ± 4.3 years, training experience: 8.3 ± 3.6 years) performed 6 sets each of bench press and leg press at 80% 1 repetition maximum. Each set was continued until failure, with a 5-minute recovery between sets. In protocol A, HV was implemented for 30 seconds before the first, third, and fifth sets of each exercise (HV-aided recovery), whereas spontaneous breathing continued throughout the recovery before the second, fourth, and sixth sets (control recovery). In protocol B, the order of the HV and control recoveries was reversed. For both protocols, reductions in repetitions (range: -4.7% to -22.5%) and velocity (range: -23.1% to -37.7%) were consistently observed after control recovery (p < 0.05), whereas HV-aided recovery resulted in increased repetitions (range: +21.3% to +55.7%) and velocity (range: +6.3% to +15.3%) (p < 0.05) or no reductions in these measures from the previous set. The total repetitions performed across 6 sets (protocols A and B combined) were greater after the HV-aided than control recovery (p ≤ 0.001) in bench press (44 ± 10 vs. 36 ± 10 reps, increased by 27.1 ± 24.1%) and leg press (64 ± 9 vs. 50 ± 15 reps, increased by 35.2 ± 29.5%). Hyperventilation-aided recovery may boost the effectiveness of resistance training through increased training volume and lifting velocity.

Dynamic changes in electroencephalogram spectral power with varying apnea duration in older adults.

Sleep apnea elicits brain and physiological changes and its duration varies across the night. This study investigates the changes in the relative powers in electroencephalogram (EEG) frequency bands before and at apnea termination and as a function of apnea duration. The analysis was performed on 30 sleep records (375 apnea events) of older adults diagnosed with sleep apnea. Power spectral analysis centered on two 10-s EEG epochs, before apnea termination (BAT) and after apnea termination (AAT), for each apnea event. The relative power changes in EEG frequency bands were compared with changes in apnea duration, defined as Short (between 10 and 20 s), Moderate (between 20 and 30 s) and Long (between 30 and 40 s). A significant reduction in EEG relative powers for lower frequency bands of alpha and sigma were observed for the Long compared to the Moderate and Short apnea duration groups at BAT, and reduction in relative theta, alpha and sigma powers for the Long compared to the Moderate and Short groups at AAT. The proportion of apnea events showed a significantly decreased trend with increased apnea duration for non-rapid eye movement sleep but not rapid eye movement sleep. The proportion of central apnea events decreased with increased apnea duration, but not obstructive episodes. The findings suggest EEG arousal occurred both before and at apnea termination and these transient arousals were associated with a reduction in relative EEG powers of the low-frequency bands: theta, alpha and sigma. The clinical implication is that these transient EEG arousals, without awakenings, are protective of sleep. Further studies with large datasets and different age groups are recommended.

The effects of multi-stage exercise with and without concurrent cognitive performance on cardiorespiratory and cerebral haemodynamic responses.

INTRODUCTION: Studies of cerebral haemodynamics have shown changes with increased exercise intensity, but the patterns have been highly variable and reliable associations with cognitive performance have not been identified. The aim of this study was to examine whether exercise-induced changes in oxygenated haemoglobin (O2Hb) led to changes in concomitant cognitive performance. METHODS: This study examined cardiorespiratory and cerebral haemodynamics during multi-stage exercise from rest to exhaustion, with (Ex + C) and without (Ex) concurrent cognitive performance (Go/No-go task). RESULTS: The presence of the cognitive task affected both cardiorespiratory and cerebral haemodynamics. The patterns in the cerebral haemodynamics during Ex and Ex + C diverged above the respiratory compensation threshold (RCT), but differences were significant only at 100% [Formula: see text], displaying increased deoxygenated haemoglobin (HHb), decreased difference between oxygenated and deoxygenated haemoglobin (HbDiff), and decreased cerebral oxygenation (COx) during Ex + C. More complex haemodynamic trends against intensity during Ex + C suggested that the presence of a cognitive task increases cerebral metabolic demand at high exercise intensities. The levels of O2Hb, HHb, HbDiff and total haemoglobin increased most steeply at intensities around the RCT during both Ex and Ex + C, but these changes were not accompanied by improved cognitive performance. CONCLUSION: The primary hypothesis, that cognitive performance would match changes in O2Hb, was not supported. Small variations in reaction time and response accuracy across exercise intensities were not significant, suggesting that cognitive performance is unaffected by intense short-duration exercise. Our results add further evidence that exercise-induced changes in cerebral haemodynamics do not affect cognitive performance.

Effects of Hyperventilation on Repeated Pedaling Sprint Performance: Short vs. Long Intervention Duration.

Sakamoto, A, Naito, H, and Chow, C-M. Effects of hyperventilation on repeated pedaling sprint performance: short vs. long intervention duration. J Strength Cond Res 32(1): 170-180, 2018-Previously, hyperventilation (HV)-induced respiratory alkalosis, implemented during the last 30 seconds of each 60-second recovery that separated repeated pedaling sprints, has been shown to attenuate performance decrement. The present study investigated whether the ergogenic effects of HV would hold if the HV duration was shortened or extended. Seventeen power-trained athletes performed 10 seconds × 10 sets of standing pedaling sprints on a cycle ergometer, with a 60-second interset recovery and the load (kp) set at 0.075 × body mass, under 3 breathing conditions: control, HV of 15 seconds (HVshort), and HV of 45 seconds (HVlong). Subjects breathed spontaneously during each 60-second recovery for the control condition. Under HVshort and HVlong conditions, subjects hyperventilated at 60 breaths·min with near-maximum tidal volume during the last 15 or 45 seconds, respectively, of each recovery period. Peak and mean pedaling power outputs (POpeak and POmean) were documented for each sprint set to compare performance decrements between conditions. No significant condition effect or condition × time interaction was found for POpeak and POmean. The lack of ergogenic effects with HVlong may be ascribed to a complex interaction between the positive (augmented buffering effects) and negative effects of HV (decreased aerobic energy metabolism and exaggerated discomfort sensation of increased ventilatory work). For HVshort, the implemented duration may have been too short to yield positive physiological effects. A practical implication is that ergogenic effects may be impaired when HV is too short or too long, with the duration of around 30 seconds being the target for this exercise type.

Hyperventilation-induced respiratory alkalosis falls short of countering fatigue during repeated maximal isokinetic contractions.

PURPOSE: Hyperventilation, implemented during recovery of repeated maximal sprints, has been shown to attenuate performance decrement. This study evaluated the effects of hyperventilation, using strength exercises, on muscle torque output and EMG amplitude. METHODS: Fifteen power-trained athletes underwent maximal isokinetic knee extensions consisting of 12 repetitions × 8 sets at 60°/s and 25 repetitions × 8 sets at 300°/s. The inter-set interval was 40 s for both speeds. For the control condition, subjects breathed spontaneously during the interval period. For the hyperventilation condition, subjects hyperventilated for 30 s before each exercise set (50 breaths/min, PETCO2: 20-25 mmHg). EMG was recorded from the vastus medialis and lateralis muscles to calculate the mean amplitude for each contraction. RESULTS: Hyperventilation increased blood pH by 0.065-0.081 and lowered PCO2 by 8.3-10.3 mmHg from the control values (P < 0.001). Peak torque declined with repetition and set numbers for both speeds (P < 0.001), but the declining patterns were similar between conditions. A significant, but small enhancement in peak torque was observed with hyperventilation at 60°/s during the initial repetition phase of the first (P = 0.032) and fourth sets (P = 0.040). EMG amplitude also declined with set number (P < 0.001) for both speeds and muscles, which was, however, not attenuated by hyperventilation. CONCLUSION: Despite a minor ergogenic effect in peak torque at 60°/s, hyperventilation was not effective in attenuating the decrement in torque output at 300°/s and decrement in EMG amplitude at both speeds during repeated sets of maximal isokinetic knee extensions.

Combined caffeine and carbohydrate ingestion: effects on nocturnal sleep and exercise performance in athletes.

PURPOSE: In athletes, caffeine use is common although its effects on sleep have not been widely studied. This randomised, double-blind, placebo-controlled crossover trial investigated the effects of late-afternoon caffeine and carbohydrate-electrolyte (CEB) co-ingestion on cycling performance and nocturnal sleep. METHODS: Six male cyclists/triathletes (age 27.5 ± 6.9 years) completed an afternoon training session (TS; cycling 80 min; 65% VO2max) followed by a 5 kJ kg(-1) cycling time trial (TT). Caffeine (split dose 2 × 3 mg kg(-1)) or placebo was administered 1 h prior and 40 min into the TS. A 7.4% CEB (3 ml kg(-1) every 15 min) was administered during the TS, followed 30 min after by a standardised evening meal. Participants retired at their usual bedtime and indices of sleep duration and quality were monitored via polysomnography. DATA: mean ± SD. RESULTS: All participants performed better in the caffeine TT (caffeine 19.7 ± 3.3; placebo 20.5 ± 3.5 min; p = 0.006), while ratings of perceived exertion (caffeine 12.0 ± 0.6; placebo 12.9 ± 0.7; p = 0.004) and heart rate (caffeine 175 ± 6; placebo 167 ± 11 bpm; p = 0.085) were lower in the caffeine TS. Caffeine intake induced significant disruptions to a number of sleep indices including increased sleep onset latency (caffeine 51.1 ± 34.7; placebo 10.2 ± 4.2 min; p = 0.028) and decreased sleep efficiency (caffeine 76.1 ± 19.6; placebo 91.5 ± 4.2%; p = 0.028), rapid eye movement sleep (caffeine 62.1 ± 19.6; placebo 85.8 ± 24.7 min; p = 0.028) and total sleep time (caffeine 391 ± 97; placebo 464 ± 49 min; p = 0.028). CONCLUSIONS: This study supports a performance-enhancing effect of caffeine, although athletes (especially those using caffeine for late-afternoon/evening training and competition) should consider its deleterious effects on sleep.

Hyperventilation as a strategy for improved repeated sprint performance.

Repeated high-intensity sprints incur substantial anaerobic metabolic challenges and create an acidic muscle milieu that is unfavorable for subsequent performance. Hyperventilation, resulting in respiratory alkalosis, acts as a compensatory mechanism for metabolic acidosis. This study tested the hypothesis that hyperventilation performed during recovery intervals would attenuate performance decrement in repeated sprint pedaling. Thirteen male university athletes performed 10 sets of 10-second maximal pedaling on a cycle ergometer with a 60-second recovery between sets under control (spontaneous breathing) and hyperventilation conditions in a crossover counter-balanced manner. Pedaling load was set at 0.075 × body mass. Peak and mean power outputs were documented for each set to compare performance decrements for 10 sets between conditions. Hyperventilation (60 breaths per minute and end-tidal partial pressure of CO2 maintained at 20-25 mm Hg) was performed 30 seconds before each sprint set. This intervention successfully increased blood pH by 0.03-0.07 but lowered P(CO2) by 1.2-8.4 mm Hg throughout exercise (p < 0.001). The peak and mean power outputs, and blood [La] accumulation were not significantly different between the conditions. However, a significant condition × time interaction existed for peak power (p = 0.035) and mean power (p = 0.023), demonstrating an attenuation in power decrement in later sprint sets with hyperventilation. In conclusion, hyperventilation implemented during recovery intervals of repeated sprint pedaling attenuated performance decrements in later exercise bouts that was associated with substantial metabolic acidosis. The practical implication is that hyperventilation may have a strategic role for enhancing training effectiveness and may give an edge in performance outcomes.

Efficacy of Morning Shorter Wavelength Lighting in the Visible (Blue) Range and Broad-Spectrum or Blue-Enriched Bright White Light in Regulating Sleep, Mood, and Fatigue in Traumatic Brain Injury: A Systematic Review.

Traumatic brain injury (TBI) profoundly affects sleep, mood, and fatigue, impeding daily functioning and recovery. This systematic review evaluates the efficacy of morning shorter wavelength lighting in the visible (blue) range and broad-spectrum or blue-enriched bright white light exposure in mitigating these challenges among TBI patients. Through electronic database searches up to May 2023, studies assessing sleep, circadian rhythm, sleepiness, mood, and fatigue outcomes in TBI patients exposed to morning shorter wavelength lighting in the visible (blue) range and broad-spectrum or blue-enriched bright white light were identified. Seven studies involving 309 participants met the inclusion criteria. Results indicated consistent advancement in sleep timing among individuals with mild TBI, alongside improvements in total sleep time, mood, and reduced sleepiness with both types of light exposure, particularly in mild TBI cases. Notably, two studies demonstrated alleviation of fatigue exclusively in severe TBI cases following light exposure. Despite promising findings, evidence remains limited, emphasizing the need for future research with standardized protocols to confirm the potential and optimize the benefits of light therapy for TBI recovery.

The effects of moderate to vigorous aerobic exercise on the sleep need of sedentary young adults.

Exercise has been recommended for enhancing sleep; a claim linked to the belief that sleep need - defined by sleep duration and depth - is increased post-exercise to allow tissue recovery. Objective studies investigating exercise-sleep responses have produced mixed outcomes, and the disparity in results between studies may be due to differences in individual characteristics and/or exercise protocol, emphasising the importance of carefully controlled trials. We investigated the role of exercise on the sleep need of sedentary adults, after controlling for exercise mode, timing and duration. Twelve healthy volunteers (25.2 ± 4.0 years, 9 females, [Vdot]O(2)max 35.4 ± 8.8 ml· kg(-1) · min(-1)) were randomised to no-exercise or to a bout of treadmill exercise at 45%, 55%, 65% or 75% [Vdot]O(2)max in a crossover design. Sleep on no-exercise and exercise nights were assessed by polysomnography. Participants spent a greater proportion of sleep in light sleep (stage 1 + stage 2) after exercise at both 65% and 75% [Vdot]O(2)max (P < 0.05) than the no-exercise condition. There was a trend of a reduced proportion of rapid eye movement sleep with increased exercise intensity (P = 0.067). No other changes were observed in any other sleep variables. Two findings emerged: vigorous exercise did not increase sleep need; however, this level of exercise increased light sleep.

The Valsalva maneuver: its effect on intra-abdominal pressure and safety issues during resistance exercise.

During resistance exercise, a brief Valsalva maneuver (VM) is unavoidable when lifting heavy loads (>80% of maximal voluntary contraction) or when lifting lighter loads to failure. It has been proposed that the performance of the VM during resistance exercise increases the stability of the spine because of augmented intra-abdominal pressure (IAP). However, resistance trainers are often advised to avoid the VM during resistance exercise because of potential adverse vascular events. The aim of this review was to establish the effect of the VM on IAP and to evaluate if the VM during resistance exercise is a safe practice. Relevant databases were searched to examine the effect of the VM on: (a) IAP and (b) hemodynamics during resistance exercise and reported adverse events. The data show that the VM alone increases IAP and that the VM augment IAP during various resistance exercises. An incremental rise in IAP was observed as the lifting intensity and effort increased, with IAP tending to be lower compared with peak IAP from the VM alone. The VM was associated with an increase in blood pressure during resistance exercise, but the VM alone was associated with greater hemodynamic changes. In conclusion, the VM effectively increases IAP, which may assist with spine stability and trunk rigidity during resistance exercise. The health risks associated with the VM during resistance exercise remain unconfirmed.

Training practices and ergogenic aids used by male bodybuilders.

Bodybuilding involves performing a series of poses on stage where the competitor is judged on aesthetic muscular appearance. The purpose of this study was to describe training practices and ergogenic aids used by competitive bodybuilders and to determine whether training practices comply with current recommendations for muscular hypertrophy. A web-based survey was completed by 127 competitive male bodybuilders. The results showed that during the off-season phase of training (OFF), the majority of respondents performed 3-6 sets per exercise (95.3%), 7-12 repetition maximum (RM) per set (77.0%), and 61- to 120-seconds recovery between sets and exercises (68.6%). However, training practices changed 6 weeks before competition (PRE), where there was an increased number of respondents who reported undertaking 3-4 sets per exercise at the expense of 5-6 sets per exercise (p < 0.001), an increase in the number reporting 10-15RM per set from 7-9RM per set (p < 0.001), and an increase in the number reporting 30-60 seconds vs. 61-180 seconds recovery between sets and exercises (p < 0.001). Anabolic steroid use was high among respondents competing in amateur competitions (56 of 73 respondents), whereas dietary supplementation was used by all respondents. The findings of this study demonstrate that competitive bodybuilders comply with current resistance exercise recommendations for muscular hypertrophy; however, these changed before competition during which there is a reduction resistance training volume and intensity. This alteration, in addition to an increase in aerobic exercise volume, is purportedly used to increase muscle definition. However, these practices may increase the risk of muscle mass loss in natural compared with amateur bodybuilders who reportedly use drugs known to preserve muscle mass.

An Arabic version of the effort-reward imbalance questionnaire: translation and validation study.

An Arabic version of the Effort-Reward Imbalance Questionnaire was developed and validated through a translation process with cross-cultural considerations. The translated questionnaire was evaluated for reliability and validity. A Principal Components Analysis was conducted following assessment of the suitability of data for factor analysis. Components with high eigenvalues were extracted, followed by Varimax rotation. Three components with eigenvalues greater than 1.0 (50% of variance) were indicated. The analysis showed Cronbach's alpha coefficients of .82 for the Effort scale, .88 for the Reward scale, and .74 for the Overcommitment scale. The test-retest reliability was high with intra-correlation coefficients of > or = .86. The Arabic version of the Effort-Reward Imbalance Questionnaire showed adequate reliability and validity and is a suitable instrument to assess work stress in Arabic-speaking people.

Self-perception and attitude toward physical activity in overweight/obese adolescents: the "martial fitness" study.

This randomized, placebo-exercise controlled trial found that 6-months of Kung Fu training improved enjoyment of physical activity more than the placebo-exercise intervention, while both groups improved perceptions of behavioral conduct and changed strategies for physical activity. Importantly, family support for physical activity declined in subjects who had more visits to health care professionals, which is worrisome, as this represents another risk factor for sedentary behavior in this vulnerable cohort that must be overcome for successful, sustained behavioral change. Programs supporting positive attitudes of both adolescents and their families toward physical activity will be necessary to optimize exercise adoption and adherence as a means to combat the obesity epidemic in childhood and adolescence.

The study design and methodology for the ARCHER study--adolescent rural cohort study of hormones, health, education, environments and relationships.

BACKGROUND: Adolescence is characterized by marked psychosocial, behavioural and biological changes and represents a critical life transition through which adult health and well-being are established. Substantial research confirms the role of psycho-social and environmental influences on this transition, but objective research examining the role of puberty hormones, testosterone in males and oestradiol in females (as biomarkers of puberty) on adolescent events is lacking. Neither has the tempo of puberty, the time from onset to completion of puberty within an individual been studied, nor the interaction between age of onset and tempo. This study has been designed to provide evidence on the relationship between reproductive hormones and the tempo of their rise to adult levels, and adolescent behaviour, health and wellbeing. METHODS/DESIGN: The ARCHER study is a multidisciplinary, prospective, longitudinal cohort study in 400 adolescents to be conducted in two centres in regional Australia in the State of New South Wales. The overall aim is to determine how changes over time in puberty hormones independently affect the study endpoints which describe universal and risk behaviours, mental health and physical status in adolescents. Recruitment will commence in school grades 5, 6 and 7 (10-12 years of age). Data collection includes participant and parent questionnaires, anthropometry, blood and urine collection and geocoding. Data analysis will include testing the reliability and validity of the chosen measures of puberty for subsequent statistical modeling to assess the impact over time of tempo and onset of puberty (and their interaction) and mean-level repeated measures analyses to explore for significant upward and downward shifts on target outcomes as a function of main effects. DISCUSSION: The strengths of this study include enrollment starting in the earliest stages of puberty, the use of frequent urine samples in addition to annual blood samples to measure puberty hormones, and the simultaneous use of parental questionnaires.

A novel scale to assess resistance-exercise effort.

In this study, we examined the validity of a novel subjective scale for assessing resistance-exercise effort. Seventeen male bodybuilders performed five sets of 10 repetitions at 70% of one-repetition maximum, for the bench press and squat. At the completion of each set, participants quantified their effort via the rating of perceived exertion (RPE) and novel estimated-repetitions-to-failure scales, and continued repetitions to volitional exhaustion to determine actual-repetitions-to-failure. There were high correlations between estimated- and actual-repetitions-to-failure across sets for the bench press and squat (r ≥ 0.93; P < 0.05). During sets 3, 4, and 5, estimated-repetitions-to-failure predicted the number of repetitions to failure for the bench press and squat, as indicated by smaller effect sizes for differences (ES = 0.37-0.0). The estimated-repetitions-to-failure scale was reliable as indicated by high intraclass correlation coefficients (≥0.92) and narrow 95% limits of agreement (≤0.63 repetitions) for both the bench press and squat. Despite high correlations between RPE and actual-repetitions-to-failure (P < 0.05), RPE at volitional fatigue was less than maximal for both exercises. Our results suggest that the estimated-repetitions-to-failure scale is valid for predicting onset of muscular failure, and can be used for the assessment and prescription of resistance exercise.