Very little is known about the energy needs of young athletes. Recent studies using the doubly labeled water method have shown that the recommended dietary allowances for energy may be too high for normally active children and adolescents living in affluent societies. No studies of energy balance in young athletes have been published. Self-report dietary records of young athletes indicate that energy, carbohydrate, and select micronutrient intakes of certain athletic groups and individual athletes may be marginal or inadequate. Potential consequences of inadequate energy and nutrient intakes in young athletes include poor bone health, fatigue, limited recovery from injuries, menstrual dysfunction in female athletes, and poor performance. Studies of energy balance and nutrient status in young athletes are needed to better understand the nutritional needs of this group.
Energy Balance in Young Athletes
Janice L. Thompson
Physical Activity, Sedentary Time, and Frailty in Older Migrant Women From Ethnically Diverse Backgrounds: A Mixed-Methods Study
Diana Castaneda-Gameros, Sabi Redwood, and Janice L. Thompson
There is limited evidence examining the association between physical activity (PA), sedentary time (ST), frailty, and factors influencing PA behaviors in migrant older women from ethnically diverse backgrounds. The aims of this mixed-methods study were to: 1) examine PA levels and ST across frailty status; 2) identify any differences in PA/ST between ethnic and religious groups; and 3) qualitatively explore factors influencing PA among older (≥60 years) migrant women (n = 60). PA/ST were assessed using accelerometry and frailty status using the frailty phenotype. Key factors influencing PA were explored via semi-structured interviews (n = 36) and analyzed using thematic analysis. Participants were highly sedentary irrespective of frailty status. Moderate-to-vigorous-physical activity (MVPA) was independently associated with frailty. Participants spent 69% of waking time in ST, with only 15% meeting current weekly PA recommendations. Health-related and socio-cultural factors were reported as common barriers to achieving PA recommendations. Maintaining independence, preventing physical decline and depression were key factors promoting PA. Understanding the challenges and needs of this population can help to inform strategies to promote PA and thus optimize physical function.
Effects of Diet and Diet-Plus-Exercise Programs on Resting Metabolic Rate: A Meta-Analysis
Janice L. Thompson, Melinda M. Manore, and Jerry R. Thomas
Studies examining the effects of diet (D) and diet-plus-exercise (DE) programs on resting metabolic rate (RMR) report equivocal results. The purpose of this study was to use meta-analysis to determine if exercise prevents the decrease in RMR observed with dieting. Results from the 22 studies included in this analysis revealed that the majority of studies used female subjects ages 31-45 years, who were fed a relatively low-fat, high-carbohydrate diet of less than 5,023 kJ · day1. The predominant prescribed exercise was aerobic in nature, 31-60 min in duration, performed 4-5 days per week, and of moderate intensity (51-70% of
Determinants of Neighborhood Activity of Adults Age 70 and Over: A Mixed-Methods Study
Afroditi Stathi, Holly Gilbert, Kenneth R. Fox, Jo Coulson, Mark Davis, and Janice L. Thompson
This mixed-methods study investigated personal, interpersonal, and environmental factors salient to decisions about being active in neighborhoods of different levels of deprivation.
Twenty-five participants age 70 years and older (10 women) with diverse physical activity levels provided data on their weekly activity patterns (using accelerometry) and their perceived barriers to exercise (questionnaire). They also participated in semistructured individual interviews exploring the barriers and facilitators influencing neighborhood activity.
Functional limitations, lack of intrinsic motivation, and not having an activity companion were the highest impact barriers. Walkable access to amenities, positive physical activity perceptions, and existing habit of being active were the highest impact facilitators.
The perceived quality and accessibility of the built and natural environments influence neighborhood activity in older adults. However, this relationship might be altered through the influence of personal and interpersonal determinants such as maintenance of good health and functional ability and supportive social networks.
Objectively Measured Sedentary Time and its Association With Physical Function in Older Adults
Mark G. Davis, Kenneth R. Fox, Afroditi Stathi, Tanya Trayers, Janice L. Thompson, and Ashley R. Cooper
The relationship of objectively measured sedentary time (ST), frequency of breaks in ST, and lower extremity function (LEF) was investigated in a diverse sample aged ≥ 70 years (n = 217). Physical activity (PA) was assessed by accelerometry deriving moderate-vigorous PA (MVPA) minutes per registered hour (MVPA min · hr−1), registered ST (ST min · hr−1), and breaks in ST min · hr−1 (breaks · hr−1). LEF was assessed by the Short Physical Performance Battery. Univariate associations with overall LEF were MVPA (r = .523), ST (r = −.499), and breaks (r = .389). Adjusted linear regression including MVPA min · hr−1, ST min · hr−1, and breaks · hr−1 explained 41.5% of LEF variance. Each additional break · hr−1 was associated with 0.58 point increase in LEF. Breaks and MVPA had strongest independent associations with LEF. Promoting regular breaks might be useful in maintaining or increasing LEF and later life independence. This novel finding is important for the design of effective lifestyle interventions targeting older adults.
A Test of the Activity Deficit Hypothesis with Children With Movement Difficulties
Marcel Bouffard, E. Jane Watkinson, Linda P. Thompson, Janice L. Causgrove Dunn, and Sandy K.E. Romanow
An activity deficit hypothesis was posited that children with movement difficulties are less physically active during recess than age- and gender-matched controls without movement difficulties. Criteria used in identifying children with movement difficulties were (a) a score of at least 4 on the Test of Motor Impairment, (b) regular physical education student, and (c) age 80 to 109 months. An observational study was conducted over a 2-month period in recess settings with 52 subjects. Findings revealed that during recess time, children with movement difficulties were vigorously active less often, played less often with large playground equipment, were not observable for significantly more time, and spent less time in positive social interactions with others of their own gender. Accordingly, it was concluded that the data support the activity deficit hypothesis.
Daily Myofibrillar Protein Synthesis Rates in Response to Low- and High-Frequency Resistance Exercise Training in Healthy, Young Men
Brandon J. Shad, Janice L. Thompson, James Mckendry, Andrew M. Holwerda, Yasir S. Elhassan, Leigh Breen, Luc J.C. van Loon, and Gareth A. Wallis
The impact of resistance exercise frequency on muscle protein synthesis rates remains unknown. The aim of this study was to compare daily myofibrillar protein synthesis rates over a 7-day period of low-frequency (LF) versus high-frequency (HF) resistance exercise training. Nine young men (21 ± 2 years) completed a 7-day period of habitual physical activity (BASAL). This was followed by a 7-day exercise period of volume-matched, LF (10 × 10 repetitions at 70% one-repetition maximum, once per week) or HF (2 × 10 repetitions at ∼70% one-repetition maximum, five times per week) resistance exercise training. The participants had one leg randomly allocated to LF and the other to HF. Skeletal muscle biopsies and daily saliva samples were collected to determine myofibrillar protein synthesis rates using 2H2O, with intracellular signaling determined using Western blotting. The myofibrillar protein synthesis rates did not differ between the LF (1.46 ± 0.26%/day) and HF (1.48 ± 0.33%/day) conditions over the 7-day exercise training period (p > .05). There were no significant differences between the LF and HF conditions over the first 2 days (1.45 ± 0.41%/day vs. 1.25 ± 0.46%/day) or last 5 days (1.47 ± 0.30%/day vs. 1.50 ± 0.41%/day) of the exercise training period (p > .05). Daily myofibrillar protein synthesis rates were not different from BASAL at any time point during LF or HF (p > .05). The phosphorylation status and total protein content of selected proteins implicated in skeletal muscle ribosomal biogenesis were not different between conditions (p > .05). Under the conditions of the present study, resistance exercise training frequency did not modulate daily myofibrillar protein synthesis rates in young men.
Understanding the Accuracy of Parental Perceptions of Child Physical Activity: A Mixed Methods Analysis
Joanna M. Kesten, Russ Jago, Simon J. Sebire, Mark J. Edwards, Laura Pool, Jesmond Zahra, and Janice L. Thompson
Interventions to increase children’s physical activity (PA) have achieved limited success. This may be attributed to inaccurate parental perceptions of their children’s PA and a lack of recognition of a need to change activity levels.
Fifty-three parents participated in semistructured interviews to determine perceptions of child PA. Perceptions were compared with children’s measured MVPA (classified as meeting or not meeting UK guidelines) to produce 3 categories: “accurate,” “over-estimate,” and “under-estimate.” Deductive content analysis was performed to understand the accuracy of parental perceptions.
All parents of children meeting the PA guidelines accurately perceived their child’s PA; while the majority of parents whose child did not meet the guidelines overestimated their PA. Most parents were unconcerned about their child’s PA level, viewing them as naturally active and willing to be active. Qualitative explanations for perceptions of insufficient activity included children having health problems and preferences for inactive pursuits, and parents having difficulty facilitating PA in poor weather and not always observing their child’s PA level. Social comparisons also influenced parental perceptions.
Strategies to improve parental awareness of child PA are needed. Perceptions of child PA may be informed by child “busyness,” being unaware of activity levels, and social comparisons.