The Determinants of the Preferred Walking Speed in Individuals with Obesity

Walking around the preferred speed: examination of metabolic, perceptual, spatiotemporal and stability parameters

Walking is the most accessible and common type of physical activity. Exercising at one's self-selected intensity could provide long-term benefits as compared to following prescribed intensities. The aim of this study was to simultaneously examine metabolic, perceptual, spatiotemporal and stability parameters at an absolute 3 km·h-1 speed range around the individual preferred walking speed (PWS). Thirty-four young sedentary adults (18 women) volunteered to walk at seven speeds relative to their PWS in 3-min trials interspaced with 3-min rest intervals. Results indicated a significant main effect of speed on all studied variables. While metabolic, perceptual and spatiotemporal values were sensitive to the smallest change in speed (i.e., 0.5 km·h-1), a significant increase in the rate of carbohydrate oxidation and decrease in %fat oxidation were only observed at speeds above PWS. Results also revealed significantly higher coefficients of variation for stride characteristics at speeds below PWS only. Moreover, analyses of best fit models showed a quadratic relationship between most variables and speed, with the exceptions of metabolic cost of transport, rating of perceived exertion and stride duration that changed exponentially with speed. PWS coincided with optimized mechanical efficiency, fuel oxidation and gait stability. This indicated that walking below PWS decreased both mechanical efficiency and stability of gait, while walking above PWS increased carbohydrate oxidation. Those factors seem to play an important role as determinants of PWS. We suggest that walking at PWS may provide benefits in terms of fat oxidation while optimizing gait stability.

Retro walking treadmill training reduces C-reactive protein levels in overweight and obese young adults: A randomized comparative study

Background and Aims

Retro walking has been shown to acquire a greater metabolic cost, placing a higher cardiopulmonary demand on the body, when compared with forward walking at a similar speed. The aim of this study was to compare the effect of retro walking with that of forward walking on C-reactive protein (CRP) levels, body mass index (BMI) and blood pressure (BP) and to understand the influence of independent factors namely systolic blood pressure (SBP), diastolic blood pressure (DBP) and BMI on CRP in untrained overweight and obese young adults.

Methods

This was a randomised controlled trial whereby 106 participants underwent either retro walking (n = 53) or forward walking (n = 53) treadmill training four times a week for 12 weeks before and after which CRP, BMI, and BP levels were measured. Comparison of the measured values before and after intervention and between the groups was done and influence of BMI and BP on CRP levels was determined.

Results

Both groups recorded a significant decrease (p < 0.001) in CRP, BMI, and BP levels postintervention. The participants who underwent retro walking training showed a significantly (p < 0.001) higher decrease in all the outcomes as compared with the forward walking group. C-reactive protein levels were seen to be influenced by BMI and DBP.

Conclusion

Retro-walking training leads to greater decrease in CRP, BMI, and BP when compared with forward walking, and CRP levels are influenced by BMI and DBP. Retro walking treadmill training can be used preferentially to bring about reduction in cardiovascular risk factors.

Classification of moderate-intensity overground walking speed in 21- to 85-year-old adults

The Compendium of Physical Activities reports that walking at 2.5 mph associates with absolutely-defined moderate intensity (i.e., ≥3 metabolic equivalents [METs]). However, it is unclear whether this speed threshold is accurate during overground walking and/or across the adult age-span. This study aimed to identify optimal and heuristic speed thresholds associated with 3 METs during overground walking across age groups. Healthy adults (n = 248, 21-85 years old, 49% women) performed a 5-minute self-paced overground walking trial. Speed was measured using an electronic gait mat, and oxygen uptake was measured using indirect calorimetry and converted to METs. Optimal and heuristic thresholds and classification accuracy metrics were determined and compared using ROC curve analyses. Speed thresholds (95% CIs) associated with 3 METs for the whole sample, young (21-40 years), middle-aged (41-60 years) and older-aged (61-85 years) groups were 1.29 (1.25, 1.33), 1.30 (1,26, 1,35), and 1.25 (1.21, 1.29) m/s, respectively. Overall, 3 mph and 5 km/h performed better than 2.5 mph and 4.5 km/h in balancing both sensitivity and specificity (higher Youden's Indices). Overground walking speeds associated with 3 METs were similar across age groups. A heuristic threshold of 3 mph or 5 km/h may better identify absolutely-defined moderate intensity overground walking.

Objectively-measured step cadence and walking patterns in a rural African setting: a cross-sectional analysis

Objectives

To investigate free-living, accelerometry-derived step cadence and walking strategy parameters in 263 adult women (19–56 years) within a rural African setting. Participants were categorised into weight groups: Under-to-Normal Weight (UW/NW: < 25 kg/m²), Overweight-to-Obese (OW/OB: ≥ 25 kg/m²). From the minute-by-minute uni-axial accelerometry data, outcomes describing physical activity intensity, step volume, step cadence and step bouts were extracted. In addition, walking pattern parameters for step bout length and step cadence were determined.

Results

Average step volume was 13,568 steps/day, and > 85% of participants were classified as active-to-highly-active. Overall, ≈ 45% of daily steps was accumulated in the low-to-moderate intensity range. Peak cadence indices were higher in the UW/NW group (p ≤ 0.0112). For both groups, 75% of steps were accumulated in bouts > 15 min, and 95% of bouts were accumulated at 1–39 steps/min. The UW/NW group employed a more varied step cadence, and higher cadences contributed more to step accumulation than the OW/OB group (p ≤ 0.05). There were no significant group differences in bout length strategy parameters (p ≥ 0.0861). Despite no difference between the weight groups in step volume, there were differences in some step cadence indices which reflect higher step intensities, and in cadence strategies chosen to accumulate steps.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13104-022-06045-9.

The Role of Walking Experience in the Emergence of Gait Harmony in Typically Developing Toddlers

The ability to walk without support usually develops in the first year of a typically developing toddler’s life and matures further in the following years. Mature walking is characterized by the correct timing of the different gait phases that make up a full gait cycle formed by stance, swing, and double support phases. The harmony of mature walking is given by a specific self-similar structure of the ratios between the durations of these phases (stride/stance, stance/swing, swing/double support), that in adults all converge to the golden ratio (phi, about 1.618). The aim of this longitudinal, prospective, experimental study was to investigate the evolution of this gait harmonic structure in the transition from supported to independent walking. In total, 27 children were recruited and recorded at various stages of locomotor development, ranging from neonatal stepping up to an independent walking experience of about six months. Differently from walking speed that progressively increased with age, the gait phase ratios started to converge to golden value only after the first independent steps, suggesting a relation to the maturation of the walking experience. The independent walking experience seems to represent a trigger for the evolution of a locomotor harmonic pattern in toddlers learning to walk.

Causal relationship between spatiotemporal parameters of walking and the locomotor rehabilitation index in healthy people

BACKGROUND

Walking speed is a functional vital sign affecting mechanical parameters individually. Further, there is a tendency for pathological gait to occur at slower speeds, which does not always allow for an adequate comparison with normal gait. Therefore, recognizing the influence of spatiotemporal adjustments on healthy gait can broaden our understanding of the applicability of gait quality markers.

RESEARCH QUESTION

This study aimed to identify the causal relationship between the stride length-frequency walking ratio index (R_SL/SF) at the self-selected walking speed (SSWS) and optimal walking speed (OWS) and the locomotor rehabilitation index (LRI) in healthy adults.

MATERIALS AND METHODS

Healthy adults (n = 68) of both sexes aged 20-59 years were included in this study. The SSWS was determined using a 30-m walkway. The OWS and LRI were predicted by equations proposed in the literature. The volunteers walked on the treadmill at speeds corresponding to the OWS and SSWS in two bouts of 60 s each, with a break in between. The spatiotemporal parameters were recorded using a high-speed digital video camera, digitalized, and mathematically processed. Multiple linear regression was applied using the forced regression method.

RESULTS

Significant correlations were found between the LRI and R_SL/SF at the SSWS (R = 0.397; p < 0.001) and OWS (R = 0.266; p = 0.014). The regression model showed that 16 % of the variability in the LRI was attributable to the R_SL/SF variability at the SSWS. The average and 95 % confidence interval LRI were 94.7 % (91.6 %-97.8 %).

CONCLUSION

The LRI average is around 95 % for healthy and young adults and the R_SL/SF explained just 16 % of the variance in LRI.

Effect of very large body mass loss on energetics, mechanics and efficiency of walking in adults with obesity: mass-driven versus behavioural adaptations

Abstract

Understanding the mechanisms involved in the higher energy cost of walking (NC_w: the energy expenditure above resting per unit distance) in adults with obesity is pivotal to optimizing the use of walking in weight management programmes. Therefore, this study aimed to investigate the mechanics, energetics and mechanical efficiency of walking after a large body mass loss induced by bariatric surgery in individuals with obesity. Nine adults (39.5 ± 8.6 year; BMI: 42.7 ± 4.6 kg m^–2) walked at five fixed speeds before (baseline) and after the bariatric surgery (post 1 and post 2). Gas exchanges were measured to obtain NC_w. A motion analysis system and instrumented treadmill were combined to assess total mechanical work (W_tot). Mechanical efficiency (W_tot NC_w^–1) was also calculated. Participants lost 25.7 ± 3.4% of their body mass at post 1 (6.6 months; P < 0.001) and 6.1 ± 4.9% more at post 2 (12 months; P = 0.014). Mass‐normalized NC_w was similar between baseline and post 1 and decreased at post 2 compared to that at baseline (−6.2 ± 2.7%) and post 1 (−8.1 ± 1.9%; P ≤ 0.007). No difference was found in mass‐normalized W_tot during follow‐up (P = 0.36). Mechanical efficiency was similar at post 1 and post 2 when compared to that at baseline (P ≥ 0.19), but it was higher (+14.1 ± 4.6%) at post 2 than at post 1 (P = 0.013). These findings showed that after a very large body mass loss, individuals with obesity may reorganize their walking pattern into a gait more similar to that of lean adults, thus decreasing their NC_w by making their muscles work more efficiently.

Key points

A higher net (above resting) energy cost of walking (lower gait economy) is observed in adults with obesity compared to lean individuals.

Understanding the mechanisms (i.e. mass driven, gait pattern and behavioural changes) involved in this extra cost of walking in adults with obesity is pivotal to optimizing the use of walking to promote daily physical activity and improve health in these individuals.

We found that very large weight loss induced by bariatric surgery significantly decreased the energy cost of walking per kg of body mass after 1 year with similar total mechanical work per kg of body mass, resulting in an increased mechanical efficiency of walking.

Individuals with obesity may reorganize their walking pattern into a gait more similar to that of adults of normal body mass, thus decreasing their energy cost of walking by making their muscles work more efficiently.

Obesity, Even in the Metabolically Healthy, Increases the Risk of Poor Physical Performance: A Cross-Sectional Study of Older People in a Chinese Community

Objective

We examined the association between obesity and physical performance under different metabolic status.

Methods

The sample included 1395 Chinese community-dwelling participants (mean age, 71.88 ± 5.87 years; 40.9% men). Being metabolically healthy was defined as having the presence of < 3 of 5 components of metabolic syndrome (MetS); obesity was defined as having a BMI > 28 kg/m². Participants were divided into four groups based on BMI (non-obese/obese) and metabolic health (healthy/unhealthy). Physical performance was measured by grip strength, 4-m walking speed, and the timed up and go test (TUGT).

Results

After multiple adjustments, compared with metabolically healthy non-obese group, the metabolically unhealthy obese group showed lower relative grip strength, lower 4-m walking speed, and higher TUGT (P all < 0.05), and only relative grip strength of the metabolically healthy obese group was significantly lower than that of metabolically healthy non-obese (P < 0.01). Relative grip strength was negatively associated with impaired fasting glucose (β = −0.071), elevated triglycerides (β = −0.062), abdominal obesity (β = −0.230) and general obesity (β = −0.225) (P all < 0.01). Walking speed and TUGT were only associated with general obesity, rather than other metabolic components. The associations of MetS with physical performance were mainly driven by abdominal obesity.

Conclusion

Even in those who are metabolically healthy, obesity (especially general obesity) increases the risk of poor physical performance. Elderly people with general obesity and MetS, whether in combination or alone, have an increased risk of muscle dysfunction, and that combination produces a higher risk of impaired mobility.

Comparison of Gait Speed Reserve, Usual Gait Speed, and Maximum Gait Speed of Adults Aged 50+ in Ireland Using Explainable Machine Learning

Gait speed is a measure of general fitness. Changing from usual (UGS) to maximum (MGS) gait speed requires coordinated action of many body systems. Gait speed reserve (GSR) is defined as MGS-UGS. From a shortlist of 88 features across five categories including sociodemographic, cognitive, and physiological, we aimed to find and compare the sets of predictors that best describe UGS, MGS, and GSR. For this, we leveraged data from 3,925 adults aged 50+ from Wave 3 of The Irish Longitudinal Study on Ageing (TILDA). Features were selected by a histogram gradient boosting regression-based stepwise feature selection pipeline. Each model's feature importance and input-output relationships were explored using TreeExplainer from the Shapely Additive Explanations explainable machine learning package. The mean R a d j 2 (SD) from fivefold cross-validation on training data and the R a d j 2   score on test data were 0.38 (0.04) and 0.41 for UGS, 0.45 (0.04) and 0.46 for MGS, and 0.19 (0.02) and 0.21 for GSR. Each model selected features across all categories. Features common to all models were age, grip strength, chair stands time, mean motor reaction time, and height. Exclusive to UGS and MGS were educational attainment, fear of falling, Montreal cognitive assessment errors, and orthostatic intolerance. Exclusive to MGS and GSR were body mass index (BMI), and number of medications. No features were selected exclusively for UGS and GSR. Features unique to UGS were resting-state pulse interval, Center for Epidemiologic Studies Depression Scale (CESD) depression, sit-to-stand difference in diastolic blood pressure, and left visual acuity. Unique to MGS were standard deviation in sustained attention to response task times, resting-state heart rate, smoking status, total heartbeat power during paced breathing, and visual acuity. Unique to GSR were accuracy proportion in a sound-induced flash illusion test, Mini-mental State Examination errors, and number of cardiovascular conditions. No interactions were present in the GSR model. The four features that overall gave the most impactful interactions in the UGS and MGS models were age, chair stands time, grip strength, and BMI. These findings may help provide new insights into the multisystem predictors of gait speed and gait speed reserve in older adults and support a network physiology approach to their study.