Weekly Roundup

Abstract: Smoking during pregnancy is an established risk factor for adverse pregnancy outcomes and health issues for newborns later in life (1-3). National birth certificate data on cigarette smoking and the number of cigarettes smoked before and during pregnancy first became available in 2016. These data allow for the analysis of maternal cigarette use during pregnancy by numerous maternal and infant characteristics. This report describes changes in the number and percentage of mothers who smoked cigarettes at any time during pregnancy in the United States from 2016 to 2021 and changes between 2016 and 2021 in the percentage of mothers who smoked during pregnancy by maternal age, race and Hispanic origin, and state of residence.

The History and Evolution of the Back Squat in the United States

Strength and Conditioning Journal, 2022

Abstract: This article provides the first academic history of the barbell back squat and its evolution from a bodyweight exercise in the 19th century to a loaded exercise, used for a variety of purposes, in the present age. In doing so, the article highlights 3 key drivers in the evolution of the back squat—those being changes in equipment, the diversification of strength sports, and scientific communication concerning the safety and efficacy of the movement. The goal of this article was not to provide a dry and irrelevant history but rather to stress the complexity of the squat's prominence within fitness programs and the need to hold a nuance view toward the “optimal” way to approach this movement. In doing so, it examines how the movement evolved from 1 primarily done on the tips of one's toes, to a loaded movement on tippy toes, to a flat footed movement. By contextualizing the back squat's history, this article challenges rigid notions of “correct” squatting technique and encourages a more nuanced understanding of exercise selection in strength and conditioning practice. It concludes by highlighting the importance of critically examining the social construction of knowledge in fitness and sport, and the value of historical perspective in informing contemporary training practices.

Likelihood of fitness improvements during a standardised physical fitness programme in US Army trainees of different fitness levels

BMJ Military Health, 2024

Abstract: Introduction: US Army Initial Entry Training (IET) aims to develop general fitness and conditioning among large groups of trainees. Despite group mean improvement in physical fitness during IET, some trainees experience substantial gains and others experience no improvement or even declines in fitness. The purpose of this study was to examine the associations between trainee baseline fitness (Army Physical Fitness Test (APFT), the primary fitness assessment at the time of data collection) or estimated baseline body fat (%BF) and the change in fitness by the end of IET. Methods: Trainee (n=774 men, 195 women) APFT performance data were obtained, and baseline anthropometrics were used to estimate %BF. APFT performance change (final-baseline) was analysed directly (t-tests) or by quartiles of baseline APFT performance or %BF (analysis of variance). Cochran-Armitage χ2 for linear trend test and risk ratios allowed for comparison against the lowest initial performance referent quartile (Q1), providing the likelihood of fitness improvements. Significance was set at p≤0.05. Results: Performance improved (p<0.01) on all final APFT events for men and women, respectively (push-ups: +38.4% and +91.8% repetitions; sit-ups: +26.8% and +33.5% repetitions; 2-mile run: -9.6% and -10.4% time). Significant trends in both sexes indicated that moving from low-to-high initial APFT fitness quartiles, trainees were increasingly less likely to improve their fitness. Specifically, men and women in the highest initial fitness quartiles (Q4) were 22%-32% and 25%-34% less likely (p<0.01) to improve, respectively, versus the within-sex lowest initial fitness quartiles (Q1). Only the male trainee's 2-mile run time change was related to the initial %BF. Conclusions: Although most trainees' fitness improved by the end of IET, the likelihood and magnitude of improvement were clearly associated with initial fitness levels. Attention to individualised conditioning and training intensity in the physical readiness training programme of instruction may optimise training strategies across all trainee conditioning levels.

RUBBISH BIN

No rubbish this week!

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James L. Nuzzo

June 17, 2024

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Announcing a funding drive for research into childhood sex differences in muscle strength

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