Body composition and physical fitness in adults born small for gestational age at term: a prospective cohort study

There is lack of research on body composition and physical fitness in individuals born small for gestational age (SGA) at term entering mid-adulthood. We aimed to investigate these outcomes in adults born SGA at term. This population-based cohort study included 46 adults born SGA with birth weight < 10th percentile at term (gestational age ≥ 37 weeks) (22 women, 24 men) and 61 adults born at term with birth weight ≥ 10th percentile (35 women, 26 men) at 32 years. Body composition was examined anthropometrically and by 8-polar bioelectrical impedance analysis (Seca® mBCA 515). Fitness was measured by maximal isometric grip strength by a Jamar hand dynamometer, 40-s modified push-up test and 4-min submaximal step test. Participants born SGA were shorter than controls, but other anthropometric measures did not differ between the groups. Men born SGA had 4.8 kg lower grip strength in both dominant (95% CI 0.6 to 9.0) and non-dominant (95% CI 0.4 to 9.2) hand compared with controls. Grip strength differences were partly mediated by height. In conclusion, body composition and physical fitness were similar in adults born SGA and non-SGA at term. Our finding of reduced grip strength in men born SGA may warrant further investigation.

Remote, Whole-Body Interval Training Improves Muscular Endurance and Cardiac Autonomic Control in Young Adults

High-intensity interval training (HIIT) is an exercise modality acknowledged to maintain physical fitness with more engagement in an active lifestyle compared with other traditional exercise models. Nevertheless, its effects on cardiac control and physical performance in an online-guided setting are not yet clarified. The present work assessed physical fitness and heart rate variability (HRV) before and after an online, home-based HIIT program in college-age students while pandemic lockdowns were in effect. Twenty university students (age: 21.9 ± 2.4 years.) that were solely enrolled in online classes were distributed into three groups: control-CON-(n = 6), 14 min of HIIT-HIIT-14-(n = 8), and 21 min of HIIT-HIIT-21-(n = 6). A maximal push-up test was employed to assess muscular endurance and performance, and resting HRV signals were collected with wireless heart rate monitors and were processed in Kubios HRV Std. (Kubios Oy, Finland). There was an increase in total push-up capacity compared to CON (p < 0.05 HIIT-21 vs. CON; p < 0.001 HIIT-14 vs. CON) after 8 weeks. A significant interaction was observed in high-frequency and low-frequency spectra ratios after the HIIT-21 intervention (p < 0.05). The current work demonstrated that either short- or mid-volume online, whole-body HIIT improves muscle strength, whereas mid-volume HIIT (HIIT-21) was the only intervention that developed a sympathovagal adaptation. This study showed promising results on muscular endurance and cardiac autonomic modulation through whole-body HIIT practice at home.

Active and Fit Communities. Associations between Neighborhood Walkability and Health-Related Fitness in Adults

There are many health benefits of regular physical activity and improving physical fitness levels can reduce the risk of chronic disease. Accumulating evidence suggests the neighborhood built environment is important for supporting physical activity; however, few studies have investigated the contribution of the neighborhood built environment to fitness levels. We examined the associations between objectively-determined and self-reported neighborhood walkability and overall and specific components of perceived health-related fitness (cardiorespiratory, muscular strength, and flexibility) in a random sample of 592 adults from two areas of Calgary (Canada). Participants provided complete data to an online questionnaire capturing perceived cardiorespiratory fitness (CRF), muscular strength (MST), flexibility, moderate-to-vigorous intensity physical activity (MVPA), resistance training, and sociodemographic characteristics. The questionnaire also captured participant’s perceptions of their neighborhood’s walkability (Physical Activity Neighborhood Environment Scale; PANES) and the physical activity supportiveness of neighborhood parks (Park Perceptions Index; PPI). Objectively-measured neighborhood walkability was estimated using Walk Score^®. The average (SD) age of participants was 46.6 (14.8) years and 67.2% were female. Participants, on average, participated in at least 30-minutes of MVPA on 3.4 (2.1) days/week and undertook resistance training 2.0 (1.8) days/week. Adjusting for covariates, Walk Score^® was not associated with any fitness outcomes. Adjusting for covariates, the PANES index was positively associated (p < 0.05) with CRF, MST, flexibility, and overall fitness and the PPI was positively associated (p < 0.05) with all fitness outcomes except MST. Our findings provide novel preliminary evidence suggesting the neighborhood built environment may be important for supporting higher health-related fitness levels in adults.