Amateurs and Professionals in One County: Biology and Natural History in Late Victorian Yorkshire

My goals in this paper are twofold: to outline there fashioning of amateur and professional roles in life science in late Victorian Yorkshire, and to provide a revised historiography of the relationship between amateurs and professionals in this era. Some historical treatments of this relationship assume that amateurs were demoralized by the advances of laboratory science, and so ceased to contribute and were left behind by the autonomous “new biology.” Despite this view, I show that many amateurs played a vital part in the construction of a professional academic community in urban Yorkshire, and then continued to collaborate with the laboratory-based biologists. The key to any analysis of the relationship between amateurs and professionals is the great variety of amateur identities and practices in Victorian Yorkshire. The amateur-professional riftfallacy arose because laboratory biologists fashioned an identity in conscious opposition to a particular type of amateur: an ideal that belied an array of co-operative relationships. As naturalists refashioned their roles and identities in light of the changes within academe and without, debates about the practice and place of life science took place as often among amateurs as between professionals and amateurs. This revised version was published online in July 2006 with corrections to the Cover Date.     

Factors in the incidence of childlessness in Canada: An analysis of census data

The impact of the 1918 influenza pandemic on human fertility has been subject to significant scholarly debate. The current study characterizes the inter-temporal association between excess deaths during the pandemic and the subsequent birth deficit by identifying the length of time between these two phenomena using cross-correlations of monthly death and birth data from Taiwan from 1906 to 1943. The analysis demonstrates a strong and negative correlation between deaths (d) at time t and births (b) at time t + 9 (r_db(9) = –0.68, p < .0001). In other words, a significant drop in births was observed nine months after pandemic mortality peaked. The findings suggest that the 1918 influenza pandemic impacted subsequent births primarily through the mechanism of reduced conceptions and embryonic loss during the first month of pregnancy rather than through late-first-trimester embryonic loss.     

Examining Differences between Homebound Older Adult Pet Owners and Non-pet Owners in Depression,Systemic Inflammation,and Executive Function

Homebound older adults are prone to depression, which is linked to systemic inflammation that promotes executive function decline. A companion animal may reduce the negative biobehavioral processes asso- ciated with depression, inflammation, and reduced executive function in homebound older adults. The primary aim of this study was to examine dif- ferences between homebound older adult pet owners and non-pet owners in depression, salivary C-reactive protein (CRP), and executive function. The secondary aim was to determine if the level of attachment to pets was as- sociated with depression, salivary CRP, and executive function. The study was cross-sectional and investigated homebound older adult pet owners and non-pet owners (n = 88) using psychometrically reliable and valid instru- ments (Geriatric Depression Scale Short Form and CLOX 1). Salivary CRP was assessed with immunoassay. Level of attachment to pets was measured using a Likert scale (0–10). Mean age for the total sample was 75 years (SD = 9). Forty-eight (55%) participants owned pets (56% dogs, 25% cats, 4% other pets, 15% both cats and dogs). Pet owners reported a high level of attachment to pets (Median = 10). Pet owners had significantly higher ex- ecutive function than non-pet owners (t = –2.07; p = 0.04) but there were no significant differences in executive function between cat owners and dog owners (t = 1.53; p = 0.14). Pet owners and non-pet owners were similar in depression (t = –1.80, p = 0.08) and salivary CRP levels (t = 0.27, p = 0.79). Level of attachment to pets was significantly and positively correlated with executive function (r = 0.30; p = 0.04) but was not significantly correlated with depression (r = 0.04, p = 0.77) or salivary CRP (r = –0.04, p = 0.80). Compared with non-pet owners, pet owners had better executive function but similar depression and salivary CRP levels. Reasons for these findings are unclear. Significant positive correlation be- tween pet attachment and executive function suggests further investigation in this area. Future studies with larger samples and a longitudinal design are needed to investigate the biobehavioral changes over time in relation to pet ownership, level of attachment to pets, and executive func- tion in homebound older adults.     

Sleep Patterns of Day-Working,Evening High-Schooled Adolescents of São Paulo,Brazil

Children who grow up in developing countries of the world must work to help financially support their families, and they must also attend school. We investigated the impact of work on the sleep of working vs. nonworking high school students. Twenty-seven São Paulo, Brazil, public high school students (eight male and eight female working students plus six nonworking female and five nonworking male students) 14–18 yrs of age who attended school Monday–Friday between 19:00 to 22:30 h participated. A comprehensive questionnaire about work and living conditions, health status, and diseases and their symptoms was also answered. The activity level and rest pattern (sleep at night and napping during the day) were continuously assessed by wrist actigraphy (Ambulatory Monitoring, USA). The main variables were analyzed by a two-factor ANOVA with application of the Tukey HSD test for multiple comparisons, and the length of sleep during weekdays vs. weekends was compared by Student t-test. Working students went to sleep earlier weekends [F_(1,23) = 6.1; p = 0.02] and woke up earlier work days than nonworking students [F_(1,23) = 17.3; p = 0.001]. The length of nighttime sleep during weekdays was shorter among all the working [F_(1,23) = 16.7; p < 0.001] than all the nonworking students. The sleep duration of boys was shorter than of girls during weekends [F_(1,23) = 10.8; p < 0.001]. During weekdays, the duration of napping by working and nonworking male students was shorter than nonworking female students. During weekdays, working girls took the shortest naps [F_(1,23) = 5.6; p = 0.03]. The most commonly reported sleep complaint during weekdays was difficulty waking up in the morning [F_(1,23) = 6.5; p = 0.02]. During weekdays, the self-perceived sleep quality of working students was worse than nonworking students [F_(1,23) = 6.2; p = 0.02]. The findings of this study show that work has negative effects on the sleep of adolescents, with the possible build-up of a chronic sleep debt with potential consequent impact on quality of life and school learning.     

Theory of transport in linear biological systems: I. Fundamental integral equation

The conditions under which the output,γ _b (t), of a biological system is related to the input,γ _a (t), by an integral equation of the typeγ _b (t) = ∫ ₀ ^t γ _a (ω)w(t−ω)dω, where ω(t) is a transport functioncharacteristic of the system, are analyzed in detail. Methods of solving this type of integral equation are briefly discussed. The theory is then applied to problems in tracer kinetics in which input and output are sums of exponentials, and explicit formulae, which are applicable whether or not the pool is uniformly mixed, are derived for “turnover time” and “pool” size.     

Sleep Loss and Performance of Anaesthesia Trainees and Specialists

Fatigue risk associated with work schedules of hospital doctors is coming under increasing scrutiny, with much of the research and regulatory focus on trainees. However, provision of 24 h services involves both trainees and specialists, who have different but interdependent work patterns. This study examined work patterns, sleep (actigraphy, diaries) and performance (psychomotor vigilance task pre‐ and post‐duty) of 28 anaesthesia trainees and 20 specialists across a two‐week work cycle in two urban public hospitals. Trainees at one hospital worked back‐to‐back 12 h shifts, while the others usually worked 9 h day shifts but periodically worked a 14 h day (08:00–22:00 h) to maintain cover until arrival of the night shift (10 h). On 11% of day shifts and 23% of night shifts, trainees were working with ≥2 h of acute sleep loss. However, average sleep loss was not greater on night shifts, possibly because workload at night in one hospital often permitted some sleep. Post‐night shift performance was worse than post‐day shift performance for the median (t₍₁₃₁₎=3.57, p<0.001) and slowest 10% of reaction times (t₍₁₃₄₎=2.91, p<0.01). At the end of night shifts, poorer performance was associated with longer shift length, longer time since waking, greater acute sleep loss, and more total work in the past 24 h. Specialists at both hospitals had scheduled clinical duties during the day and were periodically scheduled on call to cover after‐hours services. On 8% of day shifts and 14% of day+call schedules, specialists were working with ≥2 h of acute sleep loss. They averaged 0.6 h less sleep when working day shifts (t_(23.5)=2.66, p=0.014) and 0.8 h less sleep when working day shifts+call schedules (t_(26.3)=2.65, p=0.013) than on days off. Post‐duty reaction times slowed linearly across consecutive duty days (median reaction time, t₍₁₃₁₎=?3.38, p<0.001; slowest 10%, t₍₁₆₀₎=?3.33, p<0.01; fastest 10%, t₍₁₃₈₎=?2.67, p<0.01). Poorer post‐duty performance was associated with greater acute sleep loss and longer time since waking, but better performance was associated with longer day shifts, consistent with circadian improvement in psychomotor performance across the waking day. This appears to be the first study to document sleep loss among specialist anaesthetists. Consistent with observations from experimental studies, the sleep loss of specialists across 12 consecutive working days was associated with a progressive decline in post‐duty PVT performance. However, this decline occurred with much less sleep restriction (< 1 h per day) than in laboratory studies, suggesting an exacerbating effect of extended wakefulness and/or cumulative fatigue associated with work demands. For both trainees and specialists, robust circadian variation in PVT performance was evident in this complex work setting, despite the potential confounds of variable shift durations and workloads. The relationship between PVT performance of an individual and the safe administration of anaesthesia in the operating theater is unknown. Nevertheless, the findings reinforce that any schedule changes to reduce work‐related fatigue need to consider circadian performance variation and the potential transfer of workload and fatigue risk between trainees and specialists.     

Speciation of phytate ion in aqueous solution. Non covalent interactions with biogenic polyamines

Abstract

The noncovalent interactions of phytate (Phy^6-) with biogenic amines were studied potentiometrically in aqueous solution, at t= 25°C. Several species are formed in the different H+-Phy^6--amine (A) systems, which have the general formula A_p(Phy)H_q^(12-q)-, with p ≤ 3 and 6 ≤ q ≤ 10. The stability of these species is strictly dependent on the charges involved in the formation equilibria. For the equilibrium pH_iAⁱ⁺ + H_j(Phy)⁽¹²-^j)- = A_p(Phy)H_q(^12q)-, (q = pi + j)we found the relationship logK= aζ (ζ is the charge product of reactants), where a= 0.35(0.03, valid for all the amines; this roughly indicates an average free energy contribution per bond -ΔG⁰ = 4.0 ± 0.2 kJ mol^-1. A slightly more sophisticated equation is also proposed for predicting the stability of these species. Owing to the quite high (partially protonated) phytate charge, the stability of A_p(Phy)H_q^(12-q)- species is quite high, making phytate a strong amine sequestering agent in a wide pH range.     

Age and growth of Monopterus albus Zuiew, 1793 (Synbranchidae)

Age and growth of Monopterus albus (Zuiew, 1787) in Lake Nanhu, Wuhan, Hubei Province, China, were studied from January to December 2007. A total of 418 samples were collected ranging from 18 to 86 cm total length (TL). Among these samples, ages of female were 1 ⁺ –5 ⁺ years while males were 3 ⁺ –9 ⁺ years as estimated by basihyal. The length–weight relationships and the von Bertalanffy growth curve were described for all individuals as: W_T = (2 × 10^?7) TL^3.2366 and L_t = 104.1{1‐e^{?0.108 (t + 1.625)}}. To the best knowledge of the authors, this study presents the first reference on the relationship between age and growth of this species for the management of fishery resources.     

Small angle neutron and x-ray scattering studies of concentrated protein solutions. II. Cytochrome C

Small angle neutron scattering (SANS) and small angle x-ray scattering (SAXS) techniques were used to study two series of concentrated protein solutions containing horse heart cytochrome C (a spherical protein molecule with hydrated diameter σ_H = 32.6 Å and pI = 10.2) at pD = 2.9 and 11.9, respectively. The concentration of the protein ranges from 1.2 to 24 g/dL. A titration experiment was made to determine the protein charge (Z_t) for each sample. Since the form factor of the protein was already determined from a previous experiment [C. F. Wu and S. H. Chen (1987) J. Chem. Phys. 87 , 6199–6205] at pD = 6.8, the present series of experiments was used to test the effect of protein charge on the interparticle structure factor. It is demonstrated that the absolute values of both SANS and SAXS cross sections can be calculated with a theory (called the generalized one-component macroion theory) of the interparticle structure factor, which contains a single unknown parameter, the effective protein charge Z_p. Comparison of Z_t and Z_p thus obtained shows that when the bare surface charge density of the protein calculated by using Z_t exceeds about 3 μC/cm², Z_p becomes much smaller than Z_t. This is interpreted as a charge renormalization phenomenon similar to that known to occur for highly charged polystyrene latex particles in aqueous solution [S. Alexander, P. M. Chaikin, P. Grant, G. J. Morales, and P. Pincus (1984) J. Chem. Phys. 80 , 5776–5781].     

Approximation of the Basic Reproduction Number <Emphasis Type="Italic">R</Emphasis><Subscript>0</Subscript> for Vector-Borne Diseases with a Periodic Vector Population

The main purpose of this paper is to give an approximate formula involving two terms for the basic reproduction number R ₀ of a vector-borne disease when the vector population has small seasonal fluctuations of the form p(t) = p ₀ (1+ε cos (ωt − φ)) with ε ≪ 1. The first term is similar to the case of a constant vector population p but with p replaced by the average vector population p ₀. The maximum correction due to the second term is (ε²/8)% and always tends to decrease R ₀. The basic reproduction number R ₀ is defined through the spectral radius of a linear integral operator. Four numerical methods for the computation of R ₀ are compared using as example a model for the 2005/2006 chikungunya epidemic in La Réunion. The approximate formula and the numerical methods can be used for many other epidemic models with seasonality. MSC 92D30 ⋅ 45C05 ⋅ 47A55     

Judging a Dog by Its Cover: Morphology but Not Training Influences Visitor Behavior toward Kenneled Dogs at Animal Shelters

Currently, visitor behavior in companion animal shelters is not adequately explored. A sequence of experiments investigated how visitors interacted with kenneled dogs at an animal shelter and whether training dogs to not engage in undesirable behavior in their kennels would evoke more interest from shelter visitors. In a set of two experiments, two sides of an animal shelter were differentially entered into training phases in a multiple baseline design. During the training phase, dogs were trained to not engage in undesirable in-kennel behavior (i.e., to not be in the back of the kennel, to not face backwards, to not lean on kennel walls, and to not bark) through pairing of the visual presentation of the experimenters (experiment 1) and shelter visitors (experiment 2) with treats. Across both experiments, visitors attended to approximately 35% of kenneled dogs and only spent an average of 15 s looking at individual dogs. We found that whereas training was effective in decreasing undesirable behavior in dogs (experiment 1: U = 4.83, p < 0.0001; experiment 2: U = 4.01, p = 0.0001), only morphology influenced visitor behavior. In experiment 1, morphologically preferred dogs (i.e., puppies, long-coated dogs, small dogs, and certain breeds) had a 1.3 times higher frequency of visits to their kennel (F_{(1, 248)} = 5.93, p < 0.05), and in experiment 2, these dogs had a 9 times higher frequency of being taken out of their kennel for further inspection (F_{(1, 69)} = 4.66, p < 0.05), compared to other dogs. One reason for a lack of effect of training may be the relatively small number of visitors observed (n = 115 across both experiments). An alternative reason may be that shelter visitors pay more attention to the morphology rather than the lack of undesirable behavior of kenneled dogs.     

The Estimation of a Multivariate Fitness Function from Several Samples Taken from a Population

The situation is considered where the multivariate distribution of certain variables X₁, X₂, …, X_p is changing with time in a population because natural selection related to the X's is taking place. It is assumed that random samples taken from the population at times t₁, t₂, …, t_s are available and it is desirable to estimate the fitness function w_t(x₁, x₂,…,x_p) which shows how the number of individuals with X_i = x_i, i = 1, 2, …, p at time t is related to the number of individuals with the same X values at time zero. Tests for population changes are discussed and indices of the selection on the population dispersion and the population mean are proposed. The situation with a multivariate normal distribution is considered as a special case. A maximum likelihood method that can be applied with any form of population distribution is proposed for estimating w_t. The methods discussed in the paper are illustrated with data on four dimensions of male Egyptian skulls covering a time span from about 4500 B.C. to about 300 A.D. In this case there seems to have been very little selection on the population dispersion but considerable selection on means.     

Alteration of tank dimensions reduces male aggression in the swordtail

Intraspecific agonism is a problem in fish culture. This has corresponding fish welfare implications. As the design of the holding container may moderate aggressive behaviour, the aim of this study was to reduce agonistic behaviour by altering tank dimensions without changing the available volume. The study used swordtails, a popular aquarium species in which dominance hierarchies between males are common. The frequency of attacks initiated by dominant males against subordinate males was significantly reduced in tanks with smaller surface area (t₍₁₂₎ = ?3.849, P = 0.002) while the frequency of mating displays, assumed to be a measure of normal behaviour, remained unchanged (t₍₁₂₎ = 1.126, P = 0.282). The time that subordinate males spent feeding was also unaffected (t₍₁₂₎ = ?0.081, P = 0.937) while dominant males reduced the time spent feeding in tanks with smaller surface area (t₍₁₂₎ = ?3.468, P = 0.005). However, this is unlikely to be detrimental to the health of dominant males but may reflect a decreased food requirement through reduced energy expenditure. Alteration of tank dimensions in this way is therefore a simple means for small‐scale facilities and pet stores to reduce agonistic behaviour in swordtails.     

NUCLEOTYPIC EFFECT IN HOMEOTHERMS: BODY-MASS-CORRECTED BASAL METABOLIC RATE OF MAMMALS IS RELATED TO GENOME SIZE

The body-mass-corrected rate of basal metabolism in mammals is found to be negatively correlated with genome size, which is possibly linked to average cell size. The correlation, already significant at the species level (r_sp = –0.61, P < 0.0002), gradually strengthens as mean values for higher taxonomic levels (genera, families, and orders) are substituted in place of the species points (r_gen = –0.65, P < 0.0002; r_fam = –0.71, P < 0.0004; r_ord = –0.81, P < 0.008). This finding suggests that a sizeable part of the mammalian (above 25% of human) genome can be used for evolutionary adjustment of metabolic rate resulting from nucleotypic effect independently of body size. The total variance of mammalian genome-size values is found to be divided into two parts: within genera (43%) and taxonomic levels higher than order (57%), with no tangible variance being added between these taxonomic levels; whereas the body-mass-corrected rate of basal metabolism varies mainly at family (42%) and order (53%) levels. The only order for which there seems to be a necessary minimum of data for intraorder analysis (rodents) shows a not statistically significant correlation at the species level (r_sp = –0.47; P < 0.09), significant at the genus level (r_gen = –0.74; P < 0.04), and very high at the family level (r_fam = –0.98; P < 0.03). The concept of ultimate (distant) characters consolidation is proposed. In birds, with average genome sizes 40% of those of mammals, and similarly narrower ranges both of genome sizes and of body-mass-corrected metabolic rates, the correlation was not significant.     

Amateur Certification in Archaeology:

Abstract

Amateur and professional archeologists alike have called again and again for more public education, particularly as destruction of archeological sites has accelerated. Several programs focusing on education through certification programs are reviewed. Problems of amateur participation, relevance to the community and university, and publication are discussed. It is concluded that a well-planned program of amateur education and certification can be an effective tool in the creation of a public ethic of conservation. Through such a program, archeology can benefit amateurs and professionals, museums and schools, communities and individuals. In short, it offers the possibility of a true “public archeology.”     

A model of photosystem II for the analysis of fast fluorescence rise in plant leaves

The polyphasic patterns of fluorescence induction rise in pea leaves in vivo and after the treatment with ionophores have been studied using a Plant Efficiency Analyzer. To analyze in detail photosystem II (PS II) electron transfer processes, an extended PS II model was applied, which included the sums of exponential functions to specify explicitly the light-driven formation of the transmembrane electric potential (ΔΨ(t)) as well as pH in the lumen (pH_L(t)) and stroma (pH_S(t)). PS II model parameters and numerical coefficients in ΔΨ(t), pH_L(t), and pH_S(t) were evaluated to fit fluorescence induction data for different experimental conditions: leaf in vivo or after ionophore treatment at low or high light intensity. The model imitated changes in the pattern of fluorescence induction rise due to the elimination of transmembrane potential in the presence of ionophores, when ΔΨ = 0 and pH_L(t), pH_S(t) changed to small extent relative to control values in vivo, with maximum ΔΨ(t) ∼ 90 mV and ΔΨ(t) ∼ 40 mV for the stationary state at ΔpH ≅ 1.8. As the light intensity was increased from 300 to 1200 μmol m⁻² s⁻¹, the heat dissipation rate constants increased threefold for nonradiative recombination of P680⁺Phe⁻ and by ∼30% for P680⁺Q_A⁻. The parameters ΔΨ, pH_S and pH_L were analyzed as factors of PS II redox state populations and fluorescence yield. The kinetic mechanism of fluorescence quenching is discussed, which is related with light-induced lumen acidification, when ⁺Q_A⁻ and P680⁺ recombination probability increases to regulate the Q_A reduction.     

Measurement of the chlorophyll fluorescence induction kinetics with a 10 µs time resolution and its application in the forest decline research

Summary Measurement methods are described which determine the initial phase of the fluorescence induction kinetics with a maximum time resolution of 10 µs simultaneously for the two fluorescence componentsF ₆₈₅(t) andF ₁₃₀(t) selected by filters at the wavelengths 685 nm and 730 nm, respectively. The excitation light provided by a He-Ne laser (632.8 nm) is switched on within 0.3 µs (maximum intensityI _e=12 mW/cm²).F _o,F _p, andF _s, the initial-, peak-, and steady-state intensity and the initial valueR _o of the ratioR(t)=F ₇₃₀(t)/F ₆₈₅(t) can accurately be determined as well as the initial time derivativeF _o ^* of the fluorescence intensity.F _o andF _o ^* are related to the quantum yield _a of the antenna and to the photochemical quantum yield _pc, respectively. Spruce, oak, birch, poplar, and soy bean show a decline ofR(t) fromR _o to a first minimumR _b at some 10 ms which has a similar value as the second minimumR _p in the time range of seconds. Furthermore, the initial valueR _o and the steady-state valueR _S ofR(t) are also very similar. Measurements on spruce with water deficiency and with varying excitation light intensityI _e show effects on the initial phase of the fluorescence induction kinetics. Further measurements on spruce of different damage classes indicate that for the current year's needles the ratioF _p/F_o, is the most sensitive parameter to differentiate between the damage classes and thatF _o/F_s andR _o/R_b are also affected. As demonstrated by measurements on leaves of soy beans, the initial decrease ofR(t) fromR _o toR _b originates from a change of the fluorescence spectrum because no change of the leaf transmission can be observed in the time range between 10 µs and 1 ms.     

Generalized stable population theory

In generalizing stable population theory we give sufficient, then necessary conditions under which a population subject to time dependent vital rates reaches an asymptotic stable exponential equilibrium (as if mortality and fertility were constant). If x ₀(t) is the positive solution of the characteristic equation associated with the linear birth process at time t, then rapid convergence of x ₀(t) to x ₀ and convergence of mortality rates produce a stable exponential equilibrium with asymptotic growth rate x ₀–1. Convergence of x ₀(t) to x ₀ and convergence of mortality rates are necessary. Therefore the two sets of conditions are very close. Various implications of these results are discussed and a conjecture is made in the continuous case.     

ALGORITHM FOR APPLICATION OF FOURIER ANALYSIS FOR BIORHYTHMIC BASELINES OF PHARMACODYNAMIC INDIRECT RESPONSE MODELS

The change of an indirect pharmacological response R(t) can be described by a periodic time-dependent production rate k_in (t) and a first-order loss constant k_out. If k_in(t) follows some biological rhythm (e.g., circadian), then the response R(t) also displays a periodic behavior. A new approach for describing the input function in indirect response models with biorhythmic baselines of physiologic substances is introduced. The present approach uses the baseline (placebo) response R_b(t) to recover the equation for k_in(t). Fourier analysis provides an approximate equation for R_b(t) that consists of terms (usually two or three) of the Fourier series (harmonics) that contribute most to the overall sum. The model differential equation is solved backward for k_in(t), yielding the equation involving R_b(t). A computer program was developed to perform the square L²-norm approximation technique. Fourier analysis was also performed based on nonlinear regression. Cortisol suppression after inhalation of fluticasone propionate (FP) was modeled based on the inhibition of the secretion rate k_in(t) using ADAPT II. The pharmacodynamic parameters k_out and IC₅₀ were estimated from the model equation with k_in(t) derived by the new approach. The proposed method of describing the input function needs no assumption about the behavior of k_in(t), is as efficient as methods used previously, and is more flexible in describing the baseline data than the nonlinear regression method. (Chronobiology International, 17(1), 77–93, 2000)     

Racial Differences in Relative Skeletal Muscle Mass Loss During Diet‐Induced Weight Loss in Women

Objective

It is unclear whether there are race‐specific differences in the maintenance of skeletal muscle during energy restriction. Changes in relative skeletal muscle index (RSMI; limb lean tissue divided by height squared) were compared following (1) diet alone, (2) diet + aerobic training, or (3) diet + resistance training.

Methods

Overweight, sedentary African American (AA; n = 72) and European American (EA; n = 68) women were provided an 800‐kcal/d diet to reduce BMI < 25 kg/m². Regional fat‐free mass was measured with dual‐energy x‐ray absorptiometry. Steady‐state VO₂ and heart rate responses during walking were measured.

Results

AA women had greater RSMI and preserved RSMI during diet alone, while RSMI was significantly reduced among EA women (EA women –3.6% vs. AA women + 1.1%; P < 0.05). Diet + resistance training subjects retained RSMI (EA women + 0.2% vs. AA women + 1.4%; P = 50.05), whereas diet + aerobic training subjects decreased RSMI (EA women –1.4% vs. AA women –1.5%; P < 0.05). Maintenance of RSMI was related to delta walking ease and economy.

Conclusions

Compared with AA women, EA women are less muscular and lose more muscle during weight loss without resistance training. During diet‐induced weight loss, resistance training preserves skeletal muscle, especially among premenopausal EA women. Maintenance of muscle during weight loss associates with better ease and economy of walking.