The Effect of Obesity Class on the Energetics and Mechanics of Walking

Heart Rate Responses of Post-Menopausal Women to Zumba Gold® Classes

This study aimed to describe the heart rate (HR) responses of post-menopausal women during Zumba Gold® classes and to investigate the effects of body fat on HR responses. Twenty-three post-menopausal women (68.8 ± 7.2 years old; 160.0 ± 5.2 cm; 66.9 ± 11.1 kg, 36.0 ± 9.9% body fat) participated. Baseline testing assessed participants' anthropometric and fitness characteristics. Then, HR measurements were taken during four of their regular Zumba Gold® classes, and average HR (HRmean), as well as time spent in different HR intensity categories, was calculated. Linear regressions and t-tests were performed to analyse the data. The average HR during Zumba Gold® classes was 70.2% of maximum HR. Women with lower body fat achieved a significantly higher HRmean and spent less time at light to very light intensity and more time at moderate intensity compared to those with higher body fat. Body fat percentage and age were identified as determinants of time spent at moderate intensity. These findings suggest that Zumba Gold® can be an effective exercise option for post-menopausal women aiming to meet the recommended daily exercise guidelines. Understanding the HR responses during Zumba Gold® classes can aid in the development of safe and effective exercise prescriptions for this population.

Treadmill walking economy is not affected by body fat and body mass index in adults

To determine whether body fat and body mass index (BMI) affect the energy cost of walking (Cw; J/kg/m), ventilation, and gas exchange data from 205 adults (115 females; percent body fat range = 3.0%-52.8%; BMI range = 17.5-43.2 kg/m2) were obtained at rest and during treadmill walking at 1.34 m/s to calculate gross and net Cw. Linear regression was used to assess relationships between body composition indices, Cw, and standing metabolic rate (SMR). Unpaired t-tests were used to assess differences between sex, and one-way ANOVA was used to assess differences by BMI categories: normal weight, <25.0 kg/m2; overweight, 25.0-29.9 km/m2; and obese, ≥30 kg/m2. Net Cw was not related to body fat percent, fat mass, or BMI (all R2 ≤ 0.011). Furthermore, mean net Cw was similar by sex (male: 2.19 ± 0.30 J/kg/m; female: 2.24 ± 0.37 J/kg/m, p = 0.35) and across BMI categories (normal weight: 2.23 ± 0.36 J/kg/m; overweight: 2.18 ± 0.33 J/kg/m; obese: 2.26 ± 0.31, p = 0.54). Gross Cw and SMR were inversely associated with percent body fat, fat mass, and BMI (all R2 between 0.033 and 0.270; all p ≤ 0.008). In conclusion, Net Cw is not influenced by body fat percentage, total body fat, and BMI and does not differ by sex.

Pendular mechanism determinants and elastic energy usage during walking of obese and non-obese children

The mechanical and metabolic responses of walking by obese children are not yet well understood. The objectives of this study were (1) to compare the pendular mechanism (recovery, phase shift by α and β values, and ratio between forward and vertical mechanical work), the maximum possible elastic energy usage and the bilateral coordination during walking between non-obese and obese children, and (2) to verify if the bilateral coordination could contribute to understanding the pendular mechanism and elastic energy usage in these populations. Nine obese (six female, 8.7 ± 0.5 years, 1.38 ± 0.04 m, 44.4 ± 6.3 kg and 24.1 ± 3.50 kg/m2 ) and eight non-obese (four female, 7.4 ± 0.5 years, 1.31 ± 0.08 m, 26.6 ± 2.1 kg and 16.4 ± 1.40 kg/m2 ) children were analysed during walking on a treadmill at five speeds: 1, 2, 3, 4 and 5 km/h. The results indicated that although the mechanical energy response of the centre of mass during walking is similar between obese and non-obese children, the obese children showed a lower pendulum-like mechanism and greater elastic energy usage during level walking. Therefore, obese children seem to use more elastic energy during walking compared to non-obese children, which may be related to their apparent higher positive work production during the double support phase. Finally, bilateral coordination presented high values at slow speeds in both groups and requires further attention due to its association with falls. NEW FINDINGS: What is the central question of this study? Are there any differences of the pendular and elastic mechanisms and bilateral coordination during walking between non-obese and obese children? What is the main finding and its importance? To our knowledge, this study is the first to analyse the mechanical energy usage and the bilateral coordination of obese and non-obese children during walking. Obese children had a lower pendular recovery mechanism and used more elastic energy compared to non-obese children. The bilateral coordination was higher at slow speeds in both groups and requires further attention due to its association with falls.

The effect of severe obesity on three-dimensional ground reaction force signals during walking

BACKGROUND

The gait pattern of adults with class I obesity [30 ≤ body mass index < 35kg/m²] was characterized by altered three-dimensional ground reaction force signals compared to lean adults (18.5 ≤ body mass index < 25 kg/m²). However, results might not be generalizable to adults with severe obesity (class II and III; body mass index ≥ 35 kg/m²). Hence, the purpose of the present study was to investigate the differences in relative ground reaction force signals, i.e., normalized by body weight, between adults with severe obesity and lean adults using functional principal component analysis.

METHODS

Thirteen lean and eighteen sedentary adults with severe obesity performed a 5-min walking trial (1.11 m/s) on an instrumented treadmill. The first five functional principal components of the relative force signals (mediolateral, anterior-posterior, and vertical directions) were obtained using functional principal component analysis. Functional principal component scores were compared between groups using an analysis of covariance with age as covariable.

FINDINGS

Functional principal component analysis reported a statistically significant group effect for first functional principal component score for mediolateral (P = 0.004), and second and fifth functional principal component scores for anterior-posterior (P ≤ 0.02) force signals. Adults with severe obesity displayed a greater mediolateral force during most of the stance but similar magnitudes of the anterior-posterior and vertical forces compared to lean adults.

INTERPRETATION

Therefore, increasing the obesity level accentuates differences in mediolateral force but promotes no specific changes in anterior-posterior force likely due to chronic loading adaptation.

Analysis of Walking Economy after Sleeve Gastrectomy in Patients with Severe Obesity

BACKGROUND

Obesity is associated with a higher energy cost of walking which affects activities of daily living. Bariatric surgery with sleeve gastrectomy (SG) has beneficial effects on weight loss and comorbidities.

PURPOSE

The aim of this study was to analyze the impact of SG on walking economy in subjects with severe obesity.

METHODS

This observational cohort study included all patients with morbid obesity who were considered suitable candidates for SG between June 2017 and June 2019. Each patient underwent an incremental cardiopulmonary exercise test on a treadmill (modified Bruce protocol) one month before and six months after SG. Data on the energy cost of walking were recorded during three protocol stages (stage 0-slow flat walking: speed 2.7 km/h, slope 0%; stage ½-slow uphill walking: speed 2.7 km/h, slope 5%; stage 1-fast uphill walking: speed 4.0 km/h, slope 8%).

RESULTS

139 patients with morbid obesity (78% women; age 44.1 ± 10.7 years; BMI 42.5 ± 4.7 kg/m²) were included in the study. At six months post-SG, patients presented with a significantly decreased body weight (-30.5 ± 17.2 kg; p < 0.05), leading to an average BMI of 31.6 ± 4.2 kg/m². The net energy cost of walking (measured in J/m and J/kg/m) of the subjects was lower compared to pre-SG at all three protocol stages. This improvement was also confirmed when the subjects were grouped by gender and obesity classes.

CONCLUSION

After a significant weight loss induced by SG, regardless of the severity of obesity and gender, patients exhibited a lower energy expenditure and an improved walking economy. These changes make it easier to perform daily routines and may facilitate an increase in physical activity.

No association between body composition and walking outcomes in multiple sclerosis

BACKGROUND

One major concern of excess body weight is diminished physical function. The excess body weight associated with obesity can bring about challenges for physical function, particularly walking performance, among persons living with the consequences of a chronic, neurological disease. There is evidence that persons with multiple sclerosis (MS) have significantly reduced walking performance compared with controls; however, the relationship between body composition and walking outcomes has not been well-defined in persons with MS. To that end, the study examined the associations between body composition metrics and a comprehensive battery of walking outcomes in persons with MS recruited across a wide distribution of body mass index.

METHODS

Ambulatory participants with MS (n=64) underwent an assessment of neurological disability status using the Expanded Disability Status Scale (EDSS) and body composition metrics (i.e., percent body fat, fat mass, lean mass, bone mineral content and density) using dual-energy x-ray absorptiometry. Participants then completed the Timed 25-Foot Walk (T25FW), Timed Up and Go (TUG), 6-Minute Walk (6MW), and 12-Item Multiple Sclerosis Walking Scale (MSWS-12). We examined Spearman rank-order bivariate correlations among percent body fat, fat mass, lean mass, bone mineral content and density, T25FW, TUG, 6MW, MSWS-12, and EDSS.

RESULTS

Body composition metrics were not significantly associated with T25FW (rs=-.11, .12), TUG (rs=-.04, .11), 6MW (rs=-.01, .20), and MSWS-12 (rs=-.16, .03). Of note, body composition metrics were not correlated with disability status based on EDSS (rs=-.11, .03). Body composition metrics were not associated with walking outcomes even after controlling for EDSS.

CONCLUSION

Our data indicated that worse body composition profiles are not necessarily associated with worse walking performance, greater perception of MS-related walking impairment, or more severe disability status in MS. Future research may consider examining other health-related or disease outcomes of overweight or obesity in MS. Overall, our findings suggest that optimization of body composition may not be a target of interventions for improving walking outcomes, and future research might explore other factors that influence lower physical function in MS.