Impact of Underwater Treadmill Training on Glycemic Control, Blood Lipids, and Health-Related Fitness in Adults With Type 2 Diabetes.

IN BRIEF A large number of adults with type 2 diabetes experience comorbidities that discourage physical activity and hinder regular participation in land-based exercise programs. An aquatic exercise program is an innovative exercise modality that incorporates combined aerobic and resistance exercise. The purpose of this study was to determine if an underwater treadmill walking program featuring gradual and progressive increases in walking speed and duration has a positive effect on glycemic control, metabolic health, cardiovascular function, body composition, and leg strength in middle-aged adults with type 2 diabetes.

Use of Functional Movement Screen Scores to Predict Dynamic Balance in Physically Active Men and Women.

Scudamore, EM, Stevens, SL, Fuller, DK, Coons, JM, and Morgan, DW. Use of functional movement screen scores to predict dynamic balance in physically active men and women. J Strength Cond Res 33(7): 1848-1854, 2019-The primary focus of this study was to determine whether scores obtained from the Functional Movement Screen (FMS) can predict dynamic balance in young, healthy adults. Thirty-four physically active participants completed the FMS, and balance was assessed using measures of composite reach (CR) distance and overall stability indices (OSI) derived from Y Balance and Biodex Balance System testing, respectively. Results indicated that higher overall FMS scores were associated with better CR and OSI, and participants with FMS composite scores greater than 14 exhibited better CR compared to those with composite scores less than or equal to 14. In addition, lasso penalized regression demonstrated that (a) scores of 2 on the deep squat and 3 on the trunk stability push-up movements predicted a greater CR and (b) higher shoulder mobility scores and a rotary stability score of 3 predicted better OSI. We conclude that dynamic balance in young, active men and women can be predicted by specific FMS item scores.

From Disease to Health: Physical Therapy Health Promotion Practices for Secondary Prevention in Adult and Pediatric Neurologic Populations.

BACKGROUND AND PURPOSE: Over the last decade there has been a substantial increase in efforts to better understand how targeted physical activity and exercise interventions can be used to minimize secondary consequences arising from neurological damage in both adult and pediatric populations. This article offers an overview of contemporary research that addresses mediators of functional and neuroplastic adaptations associated with physical activity and exercise. We emphasize the important role that physical therapists can play to increase participation and improve well-being in adults and children with neurological disorders. We further highlight potential strategies to foster translation of evidence-based findings for use by clinicians and consumers. SUMMARY OF KEY POINTS: Engagement in physical activity can serve as a powerful promoter of health and well-being in adults and youth with neurologic disease, and has the potential to alter the course of disease processes. Physical therapists can play a key role in promoting fitness and wellness by encouraging active living, providing early diagnosis of disease and prescribing targeted activity interventions to improve fitness and participation, and helping individuals overcome personal and environmental barriers to an active lifestyle. RECOMMENDATIONS FOR CLINICAL PRACTICE: Physical therapists must adopt a model of rehabilitation that emphasizes secondary prevention in adults and youth with neurologic diseases. Physical therapists have a unique role in developing forward-thinking approaches in using innovative health and wellness strategies to promote positive changes in activity and exercise behaviors.

Sedentary Behavior, Physical Activity, and Bone Health in Postmenopausal Women.

The purpose of this study was to determine if bone health at the femoral neck (FN) and lumbar spine (LS) can be predicted from objectively-measured sedentary behavior and physical activity data in postmenopausal women. Waist-mounted ActiGraph GT1M and GT3X devices were used to quantify levels of sedentary and moderate-to-vigorous intensity behavior during a 7-day period in 44 older females. Bone health (normal and osteopenia/osteoporosis) of FN and LS was derived from T scores generated using dual energy x-ray absorptiometry. Binomial logistic regression analysis indicated that sedentary time and number of breaks in sedentary behavior were significant predictors of osteopenia/osteoporosis at the FN, but not at the LS. Adherence to physical activity guidelines was not a significant predictor of bone health at the FN or LS. Our findings suggest that more frequent interruptions in sedentary behavior are associated with improved bone health in postmenopausal women.

Comparison of Running Economy Values While Wearing No Shoes, Minimal Shoes, and Normal Running Shoes.

Cochrum, RG, Connors, RT, Coons, JM, Fuller, DK, Morgan, DW, and Caputo, JL. Comparison of running economy values while wearing no shoes, minimal shoes, and normal running shoes. J Strength Cond Res 31(3): 595-601, 2017-The purpose of this study was to quantify differences in running economy (RE) at 50 and 70% of each subject's velocity at V[Combining Dot Above]O2max (vV[Combining Dot Above]O2max) across barefoot and 2 mass, stack height, and heel-to-toe-drop controlled footwear conditions (minimal shoes and normal running shoes) in 9 recreational distance runners (mean age 26.8 ± 6.8 years). Over 3 days, subjects ran in one of the footwear conditions while RE (oxygen consumption) and step frequency were measured at each speed with a 5-minute rest between each trial. A 2-way repeated-measures multivariate analysis of variance (p ≤ 0.05) and Bonferroni-adjusted follow-up analyses revealed that RE was not significantly different across footwear conditions at either speed. However, those running barefoot exhibited a higher step frequency than when running in minimal (50%, p = 0.007; and 70%, p < 0.001) and standard footwear conditions (70% only, p < 0.001). Higher step frequencies were also exhibited by those running in minimal versus standard footwear (70% only, p = 0.007). Thus, RE is not affected by footwear or running barefoot in those with experience running in minimal-type footwear. Significant adjustments in step frequency when alternative footwear was introduced may help explain why RE was statistically maintained during each footwear and speed condition across but not between subjects. Therefore, determination of footwear for the enhancement of RE should be based on individual physical characteristics and preferences rather than a global recommendation of an economical running shoe.

Heart rate response during underwater treadmill training in adults with incomplete spinal cord injury.

BACKGROUND: Walking on a submerged treadmill can improve mobility in persons displaying lower limb muscle weakness and balance deficits. Little is known, however, regarding the effect of water treadmill exercise on cardiac performance in persons with incomplete spinal cord injury (iSCI). OBJECTIVE: To assess heart rate response during underwater treadmill training (UTT) in adults with iSCI. METHODS: Seven males and 4 females with iSCI (age = 48 ± 13 years; 5 ± 8 years after injury) completed 8 weeks of UTT (3 sessions per week; 3 walks per session) incorporating individually determined walking speeds, personalized levels of body weight unloading, and gradual, alternating increases in speed and duration. Heart rate was monitored during the last 15 seconds of the final 2 minutes of each walk. RESULTS: Over the course of 3 biweekly periods in which walking speed remained constant, heart rate fell by 7% (7 ± 1 b•min(-1); P < .001) in weeks 2 and 3, 14% (17 ± 6 b•min(-1); P < .001) in weeks 4 and 5, and 17% (21 ± 11 b•min(-1); P < .001) in weeks 6 and 7. CONCLUSION: In adults with iSCI, progressively greater absolute and relative reductions in submaximal exercise heart rate occurred after 2 months of UTT featuring a systematic increase in training volume.

Acquiring a stable estimate of physical activity in adults with visual impairment.

As a first step toward the development of adapted physical activity (PA) programs for adults with visual impairment (VI), the purpose of this study was to determine the time frame needed to reliably estimate weekly PA in adults with VI. Thirty-three adults with VI completed 7 days of pedometer-based PA assessment. Generalizability theory analyses were conducted to quantify sources of variance within the PA estimate and determine the appropriate number of days of PA monitoring needed for the total sample and for participants with mild-to-moderate and severe VI. A single-facet, crossed design was employed including participants and days. Participants and days correspondingly accounted for 33-55% and 0-3% of the total variance in PA. While a reliable account of PA was obtained for the total sample over a 6-day period, shorter (4-day) and longer (9-day) periods were required for persons with mild-to-moderate and severe VI, respectively.

Leg strength, preferred walking speed, and daily step activity in adults with incomplete spinal cord injuries.

BACKGROUND: The reduction in physical activity that accompanies spinal cord injury (SCI) contributes to the development of secondary health concerns. Research has explored potential strategies to enhance the recovery of walking and lessen the impact of physical disability following SCI, but further work is needed to identify determinants of community walking activity in this population. OBJECTIVES: To quantify relationships among lower extremity strength (LES), preferred walking speed (PWS), and daily step activity (DSA) in adults with incomplete SCI (iSCI) and determine the extent to which LES and PWS predict DSA in persons with iSCI. METHODS: Participants were 21 adults (age range, 21 to 62 years; AIS levels C and D) with iSCI. Maximal values of hip abduction, flexion, and extension, knee flexion and extension, and ankle dorsiflexion and plantar flexion were measured using handheld dynamometry and were summed to determine LES. PWS was calculated using a photoelectric cell-based timing system, and participants were fitted with activity monitors to measure DSA in a natural setting. RESULTS: Statistically significant (P <; .05) correlations of moderate to high magnitude (.74 to .87) were observed among LES, PWS, and DSA. Multiple regression analysis revealed that LES and PWS accounted for 83% (adjusted R2) of the variation in DSA (P <; .001). CONCLUSION: A significant proportion of the explained variance in DSA can be predicted from knowledge of LES and PWS in adults with iSCI. These findings suggest that future efforts to improve community walking behavior following SCI should be directed toward increasing LES and PWS.

A-B-C-1-2-3 Healthy Kids in Tennessee - Let's Eat Well, Play, and Be Aware Every Day: a preliminary report.

The "A-B-C-1-2-3 Healthy Kids in Tennessee - Let's Eat Well, Play, and Be Aware Every Day" project is a hands-on educational program emphasizing healthy living that targets childcare providers, the children they care for, and their families. The program was initially implemented as a pilot project in 6 middle Tennessee childcare centers. Materials were organized and developed by the Middle Tennessee Cancer Coalition's childhood action team in conjunction with staff from Middle Tennessee State University (MTSU) Center for Health and Human Services and the MTSU Center for Physical Activity and Health in Youth. The A-B-C-1-2-3 initiative served as a feasibility project to inform the conduct of field operations. Through the MTSU Center for Physical Activity and Health in Youth, an expanded 12-week pilot program took place during 2010 in 2 childcare centers. The purpose of the program is to educate childcare providers who, in turn, educate children and their parents and promote healthy lifestyles and decrease the risk of developing cancer, obesity, and other lifestyle-associated diseases and health conditions. The overall goal of the project is to decrease lifestyle and environmental cancer risk factors among Tennesseans by 2012 as detailed in the 2009-2012 Tennessee Comprehensive Cancer Control Plan and to provide educational opportunities in healthy eating and healthy weight to childcare providers detailed in the 2010-2015 Tennessee Statewide Nutrition and Physical Activity Plan using a "train the trainer approach" along with classroom and family education. In 2012, the project will partner with a statewide Tennessee Department of Health initiative, Gold Sneakers, which provides a policy piece to the A-B-C-1-2-3 Healthy Kids in Tennessee's approach to disseminate nutritional and physical activity education to childcare providers, children, and their families, offering a full-circle approach to health promotion in a childcare setting.

Use of water- and land-based gait training to improve walking capacity in adults with complete spinal cord injury: A pilot study.

OBJECTIVE: Little is known regarding the extent to which mobility can be improved using gait-based therapies in individuals with complete spinal cord injury (cSCI). Against this backdrop, the purpose of our study was to document changes in walking capacity following an extended period of underwater treadmill training (UTT) and supplemental overground walk training (OWT) in persons with cSCI. DESIGN: Longitudinal design. SETTING: University research center. PARTICIPANTS: Five adults (mean age = 41.2 ± 5.9 years) with motor-complete (AIS A), chronic (mean years post-injury = 3.2 ± 1.6 years) cSCI who had not received epidural spinal cord stimulation (eSCS). INTERVENTION: Participants underwent one year of UTT (3 walking bouts per day; 2-3 days per week). Once independent stepping activity in the water was observed, OWT, as tolerated, was performed prior to UTT. OUTCOME MEASURE: Walking capacity was evaluated using the Walking Index for Spinal Cord Injury (WISCI-II) prior to UTT (Time 1: T1), six months after the start of UTT (Time 2: T2), and following completion of UTT (Time 3: T3). RESULTS: Non-parametric analyses revealed a significant time effect (P < .05) for WISCI-II. Pre-planned comparisons revealed no difference in WISCI-II levels measured at T1 (0.20 ± 0.45) and T2 (4.80 ± 4.55) and at T2 (4.80 ± 4.55) and T3 (8.40 ± 1.34). However, the WISCI-II level obtained at T3 (8.40 ± 1.34) was significantly higher compared to the T1 value. CONCLUSION: Our preliminary findings demonstrate that in the absence of eSCS, combined UTT and supplemental OWT can improve functional walking capacity in adults with cSCI.

Visual classification of running economy by distance running coaches.

AbstractObjectives: This study assessed the ability of coaches to rank-order distance runners on running economy (RE) through visual assessment. Methods: Running economy was measured in five trained recreational distance runners at a speed of 3.57 m·s-1, with a minimum VO2 difference of 2-mL.kg-1.min-1 between adjacent runners. Following measurement of RE, participants were filmed from the front, side, and rear while running on a treadmill. Endurance coaches from high school to international level (N = 121) viewed each video and ranked the runners on a scale from 1 (most economical) to 5 (least economical). Coaches also completed a demographic questionnaire and listed running style biomechanical observations they used in determining each ranking. A cumulative odds ordinal logistic regression with proportional odds was run to determine the effect of coaching level, years of coaching experience, years of training experience, competition level, certification status, and education level, on the ability of distance running coaching to accurately rank RE among a group of runners. Results: No coaching characteristic was a significant predictor of ranking accuracy, χ2 = 3.566, p = .735. Conclusions: Visual assessment of effort, based on RE, is a difficult task, even for the trained eye and could be related to difficulty in understanding the interaction effect of various RE factors or the translation of scientific-based knowledge to the field of play. Practically, coaches should be cautious when recommending biomechanical adjustments without considering the interconnected factors related to such changes.

Influence of age on step activity patterns in children with cerebral palsy and typically developing children.

OBJECTIVE: To document the influence of age on step activity patterns in children with cerebral palsy (CP) and typically developing (TD) children. DESIGN: Cross-sectional. SETTING: All step activity data were collected in free-living environments. PARTICIPANTS: Children with CP (n=27; age, 4-18y; 22 boys, 5 girls; Gross Motor Function Classification System levels I and II) and 27 age- and sex-matched TD children were recruited through public advertisements and contacts with local clinicians. CP and TD participants were stratified into younger (<10y; n=14) and older (10-18y; n=13) age groups. INTERVENTION: Daily step activity was monitored using a step activity monitor that was individually programmed to account for the gait characteristics of each participant. Step activity data were collected in 1-minute epochs during waking hours on 3 weekdays and 1 weekend day. Stored data were analyzed to yield average values of daily step activity, percentage of inactive time (0 steps) over the entire day, and percentage of total daily active time spent in low step activity (1-15 steps/min), medium step activity (16-40 steps/min), and high step activity (>40 steps/min). MAIN OUTCOME MEASURES: Daily step activity, percentage of inactive time, and percentage of active time spent in low-, moderate-, and high-intensity step activity. RESULTS: A significant (P<.05) interaction was observed between age (younger, older) and condition (CP, TD) for daily step activity, percentage of inactive time, and percentage of active time spent in low- and high-intensity step activity. The main effect of age was significant for each physical activity measure except for relative high-intensity step activity, and the main effect of condition was significant for all physical activity measures. Follow-up analyses (P<.025) revealed that older children with CP took fewer daily steps and displayed higher relative levels of inactivity and low-intensity activity and lower relative levels of high-intensity activity compared with older TD children. Older children with CP also exhibited lower daily step activity, demonstrated higher relative levels of inactivity and low-intensity activity, and displayed lower relative levels of moderate-intensity activity compared with younger children with CP. CONCLUSIONS: Compared with younger children with CP and age- and sex-matched TD youth, older youth with CP generally displayed step activity patterns typified by lower levels of physical activity and a greater degree of inactivity. These findings highlight the need to provide multiple opportunities for adolescents with CP to engage in a variety of physical activities that are appropriate to their needs, abilities, and preferences and that can aid in maintaining functional mobility, health, and quality of life.

Functional Movement Screen Items Predict Dynamic Balance Under Military Torso Load.

INTRODUCTION: Musculoskeletal injuries threaten military readiness and impose a significant financial burden. The functional movement screen (FMS), a 7-item, preparticipation screening tool, may aid in identifying compensatory movement patterns that can hinder physical performance and lead to injuries in active-duty military personnel. The primary aim of our study was to determine if items scores from the traditional FMS or a modified FMS (mFMS) obtained under loaded conditions can predict dynamic balance scores while wearing a military load. MATERIALS AND METHODS: Thirty physically active adults (19 males and 11 females) who qualified for Army basic training completed unloaded and loaded FMS testing. Loaded balance was assessed using the Y balance test and the Biodex balance system. The mFMS and both loaded balance assessment protocols included a military load consisting of a standard issue rucksack (M.O.L.L.E.), kevlar helmet, and weighted vest (mass = 24.2 kg). RESULTS: mFMS item scores were significantly lower than FMS scores for six of the seven movement items. Both FMS and mFMS composite scores were correlated with Y balance scores (FMS: r = 0.53, P = 0.003; mFMS: r = 0.37, P = 0.043). Participants with higher composite scores (≥15) outperformed those with lower composite scores (≤14) for the FMS (P =0.006, d = 1.16) and mFMS (P = 0.031, d = 0.75). Lasso penalized regression analyses revealed that (1) higher unloaded in-line lunge subscores predicted better Y balance scores, (2) loaded trunk stability push-up scores of three predicted worse balance on the Biodex, and (3) unloaded and loaded shoulder mobility scores of 3 predicted better performance on the Biodex balance system. CONCLUSIONS: The in-line lunge subscore from the FMS was the strongest predictor of torso-loaded balance, and the FMS may be more appropriate than a torso-loaded FMS battery when predicting torso-loaded balance among adults with body composition and fitness profiles similar to those of entering military recruits. These findings provide evidence supporting the use of the conventional FMS to identify active-duty personnel who exhibit greater balance deficits and may develop related musculoskeletal injuries while performing operational tasks that require the transport of heavy loads over long distances.

Physical activity and quality of life in adults with spinal cord injury.

BACKGROUND/OBJECTIVE: To document the relationship between level of physical activity and quality of life in persons with spinal cord injury. DESIGN: Cross-sectional investigation. PARTICIPANTS/METHODS: Men (n = 32) and women (n = 30) with complete and incomplete spinal cord lesions below C6 volunteered to participate in this study. The average length of time since the onset of disability was 9 years (range, 1.5-40 years). Using an interview-formatted survey (Quality of Well-Being Scale), a measure of quality of life was obtained for each participant. Physical activity levels were determined using the Physical Activity Scale for Individuals with Physical Disabilities. RESULTS: A strong positive association (r = 0.75; P < 0.05) was observed between level of physical activity and quality of life. Multiple regression analysis also showed that when level of physical activity, anatomical location of the injury, completeness of injury, and time since injury were used as explanatory variables, level of physical activity was the only significant predictor of quality of life, accounting for 56% of the total variation in quality of life. CONCLUSIONS: Results from this study show that a significant and moderately strong positive relationship exists between level of physical activity and quality of life in adults with spinal cord injury. From a clinical perspective, these findings suggest that interventions aimed at promoting physical activity may be effective in improving quality of life in this population.

Influence of gait manipulation on running economy in female distance runners.

The aim of this investigation was to determine if gait manipulation influences running economy. Following 30 minutes of accommodation to level treadmill running at 3.35 m·s(-1) and determination of VO2peak, nine female distance runners (age = 23.3 ± 4.2 years; body mass = 57.5 ± 5.2 kg; height = 1.64 ± 0.10 m; body fat = 11.4 ± 2.4 %; VO2peak = 54.9 ± 4.1 ml·kg(-1)·min(-1)) completed two treadmill running sessions. In each session, standing VO2 was measured and subjects ran for 6 minutes at 3.35 m·s(-1) under 4 randomly-selected conditions: a) normal running (NL), b) hands behind back (BK), c) hands on head (HD), and d) running with exaggerated vertical oscillation (VOSC). During the last 2 minutes of each running bout, samples of expired air were analyzed to determine oxygen uptake (VO2). Data obtained by averaging gross VO2 values across sessions indicated that VOSC (51.0 ± 2.5 ml·kg(-1)·min(-1)) and HD (46.1 ± 2.0 ml·kg(-1)·min(-1)) resulted in significantly (p < 0.05) elevated VO2 values compared to BK (43.9 ± 2.4 ml·kg(-1)·min(-1)) and NL (43.4 2.6 ml·kg(-1)·min(-1)). VO2 measured during VOSC was also higher compared to HD. Viewed in concert, these results suggest that specific gait manipulations can produce marked decrements in running economy among trained female distance runners. Key pointsThis investigation demonstrates that specific biomechanical manipulations can produce substantive increases in the oxygen cost (VO2) of submaximal running in female distance runners.The magnitude of increases in VO2 reported in this study raises the intriguing possibility that meaningful improvements in running economy might be achieved by manipulating the gait of distance runners who exhibit specific aspects of running style that deviate markedly from the optimum.

Physical activity, calcium intake and bone health in children and adolescents.

Osteoporosis is a serious and potentially debilitating disease, which can lead to a variety of health complications and a diminished quality of life. Consequently, the development of bone mineral density (BMD) and content (BMC) during childhood and adolescence is of great importance, as it may attenuate the effects and incidence of osteoporosis later in life. Identifying the mechanisms by which bones are strengthened early in life is crucial. This review highlights research examining factors that influence BMD and BMC in children and adolescents. While a sizeable amount of variation in BMD and BMC in children and adolescents can be attributed to genetic factors and body size, studies have also shown the positive influence of physical activity and calcium intake on bone development. Research supporting the role of these modifiable factors varies according to age, sex and the bone site studied. During the pubertal years, large gains in BMD and BMC are evident. However, physical activity and calcium intake are also important to the development of BMD and BMC during the prepubertal years. Thus, actions taken throughout childhood may exert a great impact on BMD and BMC, and overall bone health as an adult.

Promotion of physical fitness and prevention of secondary conditions for children with cerebral palsy: section on pediatrics research summit proceedings.

Inadequate physical fitness is a major problem affecting the function and health of children with cerebral palsy (CP). Lack of optimal physical activity may contribute to the development of secondary conditions associated with CP such as chronic pain, fatigue, and osteoporosis. The purpose of this article is to highlight the content and recommendations of a Pediatrics Research Summit developed to foster collaborative research in this area. Two components of physical fitness-muscle strength and cardiorespiratory fitness-were emphasized. Although there is evidence to support the use of physical fitness interventions, there are many gaps in our current knowledge. Additional research of higher quality and rigor is needed in order to make definitive recommendations regarding the mode, intensity, frequency, and duration of exercise. Outcome measurements have focused on the body functions and structures level of the International Classification of Functioning, Disability and Health (ICF), and much less is known about effects at the activities and participation levels. Additionally, the influence of nutritional and growth factors on physical fitness has not been studied in this population, in which poor growth and skeletal fragility have been identified as serious health issues. Current intervention protocols and outcome measurements were critically evaluated, and recommendations were made for future research.

Within- and between-day stability of treadmill walking VO2 in children with hemiplegic cerebral palsy. Stability of walking VO2 in children with CP.

Within- and between-day stability in locomotor energy use was quantified in 13 children with hemiplegic CP. During testing, subjects were familiarized with the laboratory environment (Session 1), performed three 5-min level treadmill walks (Trials 1, 2, and 3) at 0.67 m x s-1 (Session 2), and completed a single 5-min walk (Trial 4) at 0.67 m x s-1 (Session 3). In Sessions 2 and 3, HR was assessed and expired air was collected and analyzed to determine VO2. Data analyses revealed no significant difference (P > 0.05) in either net VO2 (ml x kg-1 x min-1) or EEIHR (b x m-1) across the three trials performed in Session 2 and between average measures of net VO2 and EEIHR quantified in Session 2 and those obtained in Session 3. Mean within-day coefficient of variation (CV) values for net VO2 and EEIHR were 8.6% +/- 8.5% and 13.9% +/- 7.8%, respectively. Analysis of between-day variability and energy expenditure revealed a between-day CV value of 13.1% for net VO2 and 24.0% for EEIHR. In addition, significant inverse relationships between GMFM scores and within-day (r = -0.61) and between-day (r = -0.58) CV values for net VO2 were detected. Viewed in concert, these data suggest that fairly stable within- and between-day measures of locomotor energy expenditure during level treadmill walking can be achieved in subjects with hemiplegic CP if testing is preceded by a short period of treadmill accommodation. However, children with greater motor dysfunction may require an extended period of treadmill accommodation to reduce trial-to-trial variability in walking energy use.

Within- and between-day stability of treadmill walking VO2 in children with hemiplegic cerebral palsy, stability of walking VO2 in children with CP.

Within- and between-day stability in locomotor energy use was quantified in 13 children with hemiplegic cerebral palsy (CP). During testing, subjects were familiarized with the laboratory environment (Session 1), performed three 5 min level treadmill walks (Trials 1-3) at 0.67 m*s(-1) (Session 2), and completed a single 5 min walk (Trial 4) at 0.67 m*s(-1) (Session 3). In Sessions 2 and 3, heart rate (HR) was assessed and expired air was collected and analyzed to determine VO2. Data analyses revealed no significant difference (P > 0.05) in either net VO2 (ml kg(-1)*min(-1)) or EEI(HR) (b*m(-1)) across the three trials performed in Session 2 and between average measures of net VO2 and EEI(HR) quantified in Session 2 and those obtained in Session 3. Mean within-day coefficient of variation (CV) values for net VO2 and EEI(HR) were 8.6% +/- 8.5% and 13.9% +/- 7.8%, respectively. Analysis of between-day variability and energy expenditure revealed a between-day CV value of 13.1% for net VO2 and 24.0% for EEI(HR). In addition, significant inverse relationships between Gross Motor Function Measure (GMFM) scores and within- (r = -0.61) and between-day (r = -0.58) CV values for net VO2 were detected. Viewed in concert, these data suggest that fairly stable within- and between-day measures of locomotor energy expenditure during level treadmill walking can be achieved in subjects with hemiplegic CP if testing is preceded by a short period of treadmill accommodation. However, children with greater motor dysfunction may require an extended period of treadmill accommodation to reduce trial-to-trial variability in walking energy use.

Prediction of bone mineral density and content from measures of physical activity and sedentary behavior in younger and older females.

BACKGROUND: Little is known regarding the extent to which physical activity (PA) and sedentary behavior (SB) influence bone mineral content (BMC) and bone mineral density (BMD) in females across the lifespan. METHODS: Data from 2232 females aged 12 years and older collected as part of the 2007-2008 National Health and Nutrition Examination Survey were analyzed. Categories of PA and SB were used to predict femoral and spinal BMD and BMC in four age groups (G1: 12-17; G2: 18-39; G3: 40-64; G4: ≥ 65 years). Self-reported PA categories included sufficient moderate-to-vigorous recreational PA (S-MVRPA) and insufficient MVRPA (I-MVRPA). RESULTS: G1 females who accumulated S-MVRPA displayed greater femoral and spinal BMC and BMD compared to G1 females who displayed I-MVRPA. For G4 females, higher levels of SB were associated with lower femoral BMC and BMD. CONCLUSIONS: These findings highlight the importance of engaging in sufficient moderate-to-vigorous physical activity during adolescence and reducing sedentary behavior in older adults to improve bone health in females.