Age-Related Differences in Perceived Exertion While Walking and Running Near the Preferred Transition Speed.

PURPOSE: To investigate whether youth and adults can perceive differences in exertion between walking and running at speeds near the preferred transition speed (PTS) and if there are age-related differences in these perceptions. METHODS: A total of 49 youth (10-12 y, n = 21; 13-14 y, n = 10; 15-17 y, n = 18) and 13 adults (19-29 y) completed a walk-to-run transition protocol to determine PTS and peak oxygen uptake. The participants walked and ran on a treadmill at 5 speeds (PTS-0.28 m·s-1, PTS-0.14 m·s-1, PTS, PTS+0.14 m·s-1, PTS+0.28 m·s-1) and rated perceived exertion using the OMNI Perceived Exertion (OMNI-RPE) scale. Oxygen consumption was measured during the walk-to-run transition protocol to obtain the relative intensity (percentage of peak oxygen uptake) at PTS. OMNI-RPE scores at all speeds and percentage of peak oxygen uptake at PTS were compared between age groups. RESULTS: The 10- to 12-year-olds transitioned at a higher percentage of peak oxygen uptake than adults (64.54 [10.18] vs 52.22 [11.40], respectively; P = .035). The 10- to 14-year-olds generally reported higher OMNI-RPE scores than the 15- to 17-year-olds and adults (P < .050). In addition, the 10- to 14-year-olds failed to distinguish differences in OMNI-RPE between walking and running at PTS and PTS+0.14 m·s-1. CONCLUSIONS: Children aged 10-14 years are less able to distinguish whether walking or running requires less effort at speeds near the PTS compared with adults. The inability to judge which gait mode is less demanding could hinder the ability to minimize locomotive demands.

Improving Engagement With Biomechanics: Student Perspectives and a Professional Development Initiative.

Student engagement is an essential aspect of educational environments, and this is especially true for Science, Technology, Engineering, and Mathematics (STEM) disciplines, where student engagement declines in middle and high school years. Techniques for bolstering student engagement, such as hands-on learning, may be especially effective in the field of biomechanics since this discipline is rooted in STEM and has fundamental applications to everyday movement. To this end, this paper describes (1) the perceptions of student teachers in their first year of tertiary (undergraduate) education regarding the biomechanics content from their secondary (high school) education, and (2) a professional development initiative, in the form of a discipline-specific teacher training workshop, to enhance biomechanics resources for teachers via peer networking. The perception of student teachers in their first year of tertiary education in teaching indicated a positive relationship between perception of secondary school teaching quality and self-confidence with specific biomechanical concepts. Open responses focused on the need to cover concepts thoroughly, using practical activities where possible, and taking time to ensure understanding before progressing to more advanced concepts. The teacher training workshop provided secondary school Physical Education teachers with an opportunity to network nationally with other teachers across New Zealand, and internationally with university-based biomechanics researchers. Peer focus groups helped to design and refine sets of experiential learning activities that could be easily implemented in the classroom.

Stationary Exercise in Overweight and Normal Weight Children.

PURPOSE: This study examined differences in lower extremity kinematics and muscle activation patterns between normal weight (NW) and overweight (OW) children during stationary exercises (running in place, frontal kick, and butt kick) at submaximal intensity. METHODS: Healthy children (aged 10-13 y) were stratified into OW (n = 10; body fat percentage: 34.97 [8.60]) and NW (n = 15; body fat percentage: 18.33 [4.87]). Electromyography was recorded for rectus femoris, vastus lateralis, biceps femoris, gastrocnemius, and tibialis anterior. In addition, the ratings of perceived exertion and range of motion of hip, knee, and ankle joints were collected during stationary exercises. Repeated-measures analysis of variance compared muscle activation, range of motion, and ratings of perceived exertion between groups and exercises. Friedman test examined sequencing of muscles recruitment. RESULTS: Compared with NW, OW experienced significantly greater ratings of perceived exertion (13.7 [0.8] vs 11.7 [0.7]; P < .001) and electromyography amplitude in all muscles apart from vastus lateralis during stationary exercises. In addition, NW children used more consistent muscles' recruitment pattern in comparison with OW children. The range of motion was similar between groups at all joints. CONCLUSION: OW children may adopt a more active neuromuscular strategy to provide greater stability and propulsion during stationary exercises. Stationary exercise can be prescribed to strengthen lower extremity muscles in OW children, but mode and intensity must be considered.

Kinematic Comparison of Aquatic- and Land-Based Stationary Exercises in Overweight and Normal Weight Children.

PURPOSE: This study examined lower extremity kinematics in healthy weight (HW) and overweight (OW) children during water- and land-based stationary exercises (stationary running, frontal kick, and butt kick) at light submaximal intensity. METHODS: Participants included OW (N = 10; body fat percentage: 34.97 [8.60]) and HW (N = 15; body fat percentage: 18.33 [4.87]) children, aged 10 to 13 years. Spatiotemporal data, lower extremity joint kinematics, and rating of perceived exertion (RPE) were collected during water- and land-based stationary exercises. Repeated measures analysis of variance compared kinematic variables and RPE between groups and environments. A polygon area function compared coordination patterns between environments. RESULTS: RPE responses were significantly greater in OW than HW children on land (13.6 [0.7] vs 11.6 [0.7]; P < .001), whereas the RPE responses were similar between groups in water (11.2 [0.7] vs 11.1 [0.8]; P > .05). OW children were significantly more upright than HW children during land-based exercise, whereas there were no differences observed between groups during aquatic-based exercise. The duration of stance and swing phases, angular velocity, and cadence were significantly lower in water than on land. CONCLUSION: Compared with HW children, OW children performed stationary exercises in a more upright posture on land, with higher RPE. However, these differences diminished in water. Aquatic-based exercise may be effective in minimizing the effects of excess mass on OW children's ability to complete physical activity.

Potentiation of sprint cycling performance: the effects of a high-inertia ergometer warm-up.

Participant and protocol factors affect post-activation potentiation response. Performance enhancement is more consistent in highly-trained participants following multiple sets of a biomechanically similar conditioning activity. Providing optimal conditions, 6 international-level sprint cyclists executed multiple sets of short maximal conditioning contractions on a high-inertia ergometer before metered sprint performance. Three trial conditions were completed on separate days after a standardised warm-up: dynamic (DYN: 4 × 4 crank-cycles), isometric (ISO: 4 × 5-sec maximal voluntary contraction (MVC)), and control (CON: rest). Performance was measured from standing start to maximum velocity on an inertial-load ergometer at baseline (Pre), 4 (Post4), 8 (Post8) and 16 (Post16) min post-conditioning. Performance and biomechanical measures were assessed across 4 sprint segments, with magnitude-based inferences used to assess the likelihood that any affect was beneficial. Performance time only improved in DYN Post4, a 3.9% reduction during the first crank cycle (92% likely). On the ascending limb of the power-cadence relationship, peak torque and average power increased by 6.2% (94% likely) and 4.0% (87% likely), respectively. In ISOPost16, optimal cadence increased (82% likely) and average power improved over the descending limb (76% likely). DYN and ISO potentiated extremities of the torque-cadence relationship at distinct recovery times post-conditioning. This study suggests merit in including a high-inertia warm-up for sprint cycling.

The impact of uphill cycling and bicycle suspension on downhill performance during cross-country mountain biking.

Non-propulsive work demand has been linked to reduced energetic economy of cross-country mountain biking. The purpose of this study was to determine mechanical, physiological and performance differences and observe economy while riding a downhill section of a cross-country course prior to and following the metabolic "load" of a climb at race pace under two conditions (hardtail and full suspension) expected to alter vibration damping mechanics. Participants completed 1 lap of the track incorporating the same downhill section twice, under two conditions (hardtail and full suspension). Performance was determined by time to complete overall lap and specific terrain sections. Power, cadence, heart rate and oxygen consumption were sampled and logged every second while triaxial accelerometers recorded accelerations (128 Hz) to quantify vibration. No differences between performance times (P = 0.65) or power outputs (P = 0.61) were observed while physiological demand of loaded downhill riding was significantly greater (P < 0.0001) than unloaded. Full suspension decreased total vibrations experienced (P < 0.01) but had no effect on performance (P = 0.97) or physiological (P > 0.05) measures. This study showed minimal advantage of a full suspension bike in our trial, with further investigations over a full race distance warranted.

The influence of tyre characteristics on measures of rolling performance during cross-country mountain biking.

This investigation sets out to assess the effect of five different models of mountain bike tyre on rolling performance over hard-pack mud. Independent characteristics included total weight, volume, tread surface area and tread depth. One male cyclist performed multiple (30) trials of a deceleration field test to assess reliability. Further tests performed on a separate occasion included multiple (15) trials of the deceleration test and six fixed power output hill climb tests for each tyre. The deceleration test proved to be reliable as a means of assessing rolling performance via differences in initial and final speed (coefficient of variation (CV) = 4.52%). Overall differences between tyre performance for both deceleration test (P = 0.014) and hill climb (P = 0.032) were found, enabling significant (P < 0.0001 and P = 0.049) models to be generated, allowing tyre performance prediction based on tyre characteristics. The ideal tyre for rolling and climbing performance on hard-pack surfaces would be to decrease tyre weight by way of reductions in tread surface area and tread depth while keeping volume high.

Fractal structure enables temporal prediction in music.

1/f serial correlations and statistical self-similarity (fractal structure) have been measured in various dimensions of musical compositions. Musical performances also display 1/f properties in expressive tempo fluctuations, and listeners predict tempo changes when synchronizing. Here the authors show that the 1/f structure is sufficient for listeners to predict the onset times of upcoming musical events. These results reveal what information listeners use to anticipate events in complex, non-isochronous acoustic rhythms, and this will entail innovative models of temporal synchronization. This finding could improve therapies for Parkinson's and related disorders and inform deeper understanding of how endogenous neural rhythms anticipate events in complex, temporally structured communication signals.

Using a modified vector coding technique to describe the calcaneus-shank coupling relationship during unanticipated changes of direction: theoretical implications for prophylactic ACL strategies.

Shank rotation is associated with increased risk in lower limb injuries of weight-bearing sport activity. Straight-line running injury prevention research proposes a 'bottom-up' approach to minimising injury risk to the knee. This prophylactic recommendation is due to the observed distal-proximal coupling relationship between rearfoot and shank rotations. However, the coupling relationship between the calcaneus and shank is unknown in sports with high intensity decelerations, frequent changes of direction, associated with increased anterior cruciate ligament (ACL) injury risk. The aim of this study was to determine whether the movement of the calcaneus has a potential effect on the internal and external rotational movement of the shank, associated with ACL injury risk. We implemented a modified vector coding technique using segmental velocities in a local, anatomical reference frame to quantify the coupling relationship between the individual tri-planar calcaneus rotations and transverse plane shank rotations. During the loading phase, a distal-proximal coupling relationship between calcaneus eversion deceleration, abduction acceleration, and shank internal rotation deceleration was observed amongst most subjects. The distal-proximal coupling found between the calcaneus and shank justifies exploring interventions geared towards manipulating calcaneus motion to affect shank rotational movements during unanticipated change of direction tasks associated with ACL injury risk.

Body mass affects kinetic symmetry and inflammatory markers in adolescent knees during gait.

BACKGROUND: Early-onset osteoarthritis has been attributed to pro-inflammatory factors and biomechanical changes in obesity. However, research has yet to explore whether knee joint moments are asymmetrical in children with obesity and could precede the onset of knee osteoarthritis. The present study compares knee moment asymmetry between adolescents with and without obesity and examines the relationship between asymmetries and inflammatory biomarkers. METHODS: Twenty-eight adolescents (13-16 years) were classified as with (n = 12) or without (n = 16) obesity. Lower extremity kinetics were measured using three-dimensional motion analysis. Bilateral knee joint moments were analyzed in the sagittal, frontal, and transverse planes across stance phase. Kinetic asymmetry was calculated between the right and left sides and represented by the R2 value. Enzyme-linked immunosorbent assays analyzed serum 25-hydroxy vitamin D, interferon gamma, tumor nercrosis factor alpha, interleukin-6, and C-reactive protein levels. Parametric and non-parametric tests determined significant group differences in asymmetries and biomarkers, respectively. Spearman's correlations identified relationships between biomarkers and asymmetries with statistically significant group differences. FINDINGS: Adolescents with obesity had greater sagittal (loading, midstance) and frontal (midstance, pre-swing) plane kinetic knee asymmetry and higher concentrations of interleukin-6 and C-reactive protein. A moderately negative correlation existed between C-reactive protein and sagittal (loading, midstance) plane asymmetry, and also between interleukin-6 and frontal (pre-swing) plane asymmetry. INTERPRETATION: Inflammatory response increases with greater knee joint asymmetry, suggesting knee joint damage and altered joint loading co-exist in adolescents with obesity. Increased risk to joint health may exist in sub-phases where knee joints are improperly loaded.

Replacing Sedentary Time with Physically Active Behaviour Predicts Improved Body Composition and Metabolic Health Outcomes.

BACKGROUND: Discretionary leisure time for health-promoting physical activity (PA) is limited. This study aimed to predict body composition and metabolic health marker changes from PA reallocation using isotemporal substitution analysis. METHODS: Healthy New Zealand women (n = 175; 16-45 y) with high BMI (≥25 kg/m2) and high body fat percentage (≥30%) were divided into three groups by ethnicity (Maori n = 37, Pacific n = 54, and New Zealand European n = 84). PA, fat mass, lean mass, and metabolic health were assessed. Isotemporal substitution paradigms reallocated 30 min/day of sedentary behaviour to varying PA intensities. RESULTS: Reallocating sedentary behaviour with moderate intensity, PA predicted Maori women would have improved body fat% (14.83%), android fat% (10.74%), and insulin levels (55.27%) while the model predicted Pacific women would have improved waist-to-hip (6.40%) and android-to-gynoid (19.48%) ratios. Replacing sedentary time with moderate-vigorous PA predicted Maori women to have improved BMI (15.33%), waist circumference (9.98%), body fat% (16.16%), android fat% (12.54%), gynoid fat% (10.04%), insulin (55.58%), and leptin (43.86%) levels; for Pacific women, improvement of waist-to-hip-ratio (5.30%) was predicted. CONCLUSIONS: Sedentary behaviour must be substituted with PA of at least moderate intensity to reap benefits. Maori women received the greatest benefits when reallocating PA. PA recommendations to improve health should reflect the needs and current activity levels of specific populations.

Mini-Trampoline Jumping as an Exercise Intervention in Postmenopausal Women to Improve Women Specific Health Risk Factors.

BACKGROUND: Women tend to outlive men and are at higher risks of functional disability compared to men. Specifically, women are more likely to develop conditions like osteoporosis and stress urinary incontinence which can further increase the risk of functional disability. Regular physical activity and/or exercise programs can minimize the physiological decline that occurs during aging and can improve overall physical fitness, bone health, and pelvic floor muscle function; however, exercise programs tend to focus on only one parameter. Mini-trampoline jumping is a highly beneficial low-impact aerobic exercise capable of improving aerobic fitness, balance, muscle strength, and potentially bone health as well as pelvic floor muscle functioning. The aim of the proposed research project is to examine the benefits of a 3-month mini-trampoline exercise intervention on physical fitness, bone health, and pelvic floor muscle functioning in postmenopausal women. METHODS: Fifty postmenopausal healthy women aged 50-69 years will be recruited. Assessments on physical fitness (aerobic fitness, walking speed, balance, lower extremity strength, flexibility), bone health, and pelvic floor muscle functioning will occur within 1 week before and after the exercise intervention, including a 3-month follow-up assessment. The exercise intervention will last 12 weeks, with three sessions of 40 min each per week. CONCLUSIONS: The proposed research has the potential to improve functional ability and women-specific risk factors in older women with an innovative and fun exercise program.

Foot Muscle Strengthening and Lower Limb Injury Prevention.

Background and objectives: The active and passive structures of the foot act in unison to not only be compliant enough to assist in ground reaction force attenuation but also resist deformation to provide a stable base of support. A foot that is unable to adjust to the imposed demands during high-intensity sporting activities may alter the moments and forces acting on the joints, increasing the risk of non-contact anterior cruciate ligament ruptures (ACLR) and lateral ankle sprains (LAS). Prophylactic strengthening programs are often used to reduce the risk of these injuries, but at present, very few prophylactic programs include foot-specific strengthening strategies. The aim of this theoretical review is to ascertain the prophylactic role strengthening muscles acting on the foot may have on ACLR and LAS injury risk. Methods: Literature relating to risk factors associated with ACLR and LAS injury and the anatomy and biomechanics of normal foot function was searched. In addition, ACLR and LAS injury prevention programs were also sought. A theoretical, narrative approach was followed to synthesize the information gathered from the articles. Results: The foot segments are governed by the congruity of the articulations and the activity of the foot muscles. As such, there is a coupling effect between shank, calcaneus, midfoot, and hallux movement which play a role in both ACLR and LAS injury risk. Conclusions: Strengthening the muscles acting on the foot may have a significant impact on ACLR and LAS injury risk.

The coordination patterns of the foot segments in relation to lateral ankle sprain injury mechanism during unanticipated changes of direction.

Preventing lateral ankle sprain injuries (LAS) in females competing in court sports is a high priority, as an athlete's risk for re-injury and developing long term dysfunction increases significantly after sustaining an acute LAS. Stability to the ankle joint is passively provided by the joint congruity and ligaments, and actively by the muscles acting on the foot. The ankle joint is most stable when loaded and dorsiflexed. However, during unanticipated changes of direction, typical in court sports, the foot is often in a vulnerable unloaded, plantarflexed position. Stability of the forefoot and controlling rearfoot movement to avoid excessive ankle inversion and adduction thus becomes imperative. Information regarding the coupling relationship between the forefoot (hallux and metatarsal segments) and the rearfoot (calcaneus segment) during unanticipated changes of direction is lacking. The aim of this study was to supplement current LAS prophylactic knowledge by describing and quantifying hallux-calcaneus and metatarsal-calcaneus coupling. The coupling angles between sagittal plane hallux, tri-planar metatarsal and frontal- and transverse plane calcaneus movement, respectively, were calculated with a modified vector coding technique which used segmental velocities in a local, anatomical reference frame instead of segmental angles in a global reference frame. Coupling relationships revealed anti-phase movement between sagittal- metatarsal and frontal plane calcaneus movement throughout stance. During loading, sagittal- and frontal plane metatarsal acceleration/deceleration were coupled with frontal-transverse plane calcaneus acceleration/deceleration respectively. The remainder of the braking phase was characterized by calcaneus eversion deceleration. During propulsion, the hallux and metatarsal segments increased plantar flexion velocity in response to calcaneus inversion and adduction acceleration. As the forefoot was the only point of contact during stance, the coupling between segments were most likely neuromuscular. Strengthening intrinsic and extrinsic foot muscles may thus contribute to foot and ankle stability, adding to current prophylactic LAS strategies.

Are all Sedentary Behaviors Equal? An Examination of Sedentary Behavior and Associations with Indicators of Disease Risk Factors in Women.

Sedentary behavior increases risk for non-communicable diseases; associations may differ within different contexts (e.g., leisure time, occupational). This study examined associations between different types of sedentary behavior and disease risk factors in women, using objectively measured accelerometer-derived sedentary data. A validation study (n = 20 women) classified sedentary behavior into four categories: lying down; sitting (non-active); sitting (active); standing. A cross-sectional study (n = 348 women) examined associations between these classifications and disease risk factors (body composition, metabolic, inflammatory, blood lipid variables). Participants spent an average of 7 h 42 min per day in sedentary behavior; 58% of that time was classified as non-active sitting and 26% as active sitting. Non-active sitting showed significant (p ≤ 0.001) positive correlations with BMI (r = 0.244), body fat percent (r = 0.216), body mass (r = 0.236), fat mass (r = 0.241), leptin (r = 0.237), and negative correlations with HDL-cholesterol (r = -0.117, p = 0.031). Conversely, active sitting was significantly (p ≤ 0.001) negatively correlated with BMI (r = -0.300), body fat percent (r = -0.249), body mass (r = -0.305), fat mass (r = -0.320), leptin (r = -0.259), and positively correlated with HDL-cholesterol (r = 0.115, p = 0.035). In summary, sedentary behavior can be stratified using objectively measured accelerometer-derived activity data. Subsequently, different types of sedentary behaviors may differentially influence disease risk factors. Public health initiatives should account for sedentary classifications when developing sedentary behavior recommendations.

Perturbation-induced false starts as a test of the jirsa-kelso excitator model.

One difference between the excitator model and other theoretical models of coordination is the mechanism of discrete movement initiation. In addition to an imperative signal common to all discrete movement initiation, the excitator model proposes that movements are initiated when a threshold element in state space, the so-called separatrix, is crossed as a consequence of stimulation or random fluctuations. The existence of a separatrix predicts that false starts will be caused by mechanical perturbations and that they depend on the perturbation's direction. The authors tested this prediction in a reaction-time task to an auditory stimulus. Participants applied perturbations in the direction of motion (i.e., index finger flexion) or opposed to the motion prior to the stimulus on 1/4 of the trials. The authors found false starts in 34% and 9% of trials following flexion perturbations and extension perturbations, respectively, as compared with only 2% of trials without perturbations, confirming a unique prediction of the excitator model.

Catching fly balls in virtual reality: a critical test of the outfielder problem.

How does a baseball outfielder know where to run to catch a fly ball? The "outfielder problem" remains unresolved, and its solution would provide a window into the visual control of action. It may seem obvious that human action is based on an internal model of the physical world, such that the fielder predicts the landing point based on a mental model of the ball's trajectory (TP). However, two alternative theories, Optical Acceleration Cancellation (OAC) and Linear Optical Trajectory (LOT), propose that fielders are led to the right place at the right time by coupling their movements to visual information in a continuous "online" manner. All three theories predict successful catches and similar running paths. We provide a critical test by using virtual reality to perturb the vertical motion of the ball in mid-flight. The results confirm the predictions of OAC but are at odds with LOT and TP.

Fractal Tempo Fluctuation and Pulse Prediction.

WE INVESTIGATED PEOPLES' ABILITY TO ADAPT TO THE fluctuating tempi of music performance. In Experiment 1, four pieces from different musical styles were chosen, and performances were recorded from a skilled pianist who was instructed to play with natural expression. Spectral and rescaled range analyses on interbeat interval time-series revealed long-range (1/f type) serial correlations and fractal scaling in each piece. Stimuli for Experiment 2 included two of the performances from Experiment 1, with mechanical versions serving as controls. Participants tapped the beat at »- and ⅛-note metrical levels, successfully adapting to large tempo fluctuations in both performances. Participants predicted the structured tempo fluctuations, with superior performance at the »-note level. Thus, listeners may exploit long-range correlations and fractal scaling to predict tempo changes in music.

Age-dependent variability in spatiotemporal gait parameters and the walk-to-run transition.

Adolescents tend to exhibit more variability in their gait patterns than adults, suggesting a lack of gait maturity during this period of ongoing musculoskeletal growth and development. However, there is a lack of consensus over the age at which mature gait patterns are achieved and the factors contributing to gait maturation. Therefore, the purpose of this study was to investigate gait control and maturity in adolescents by determining if differences existed between adolescents and adults in a) the amount of spatiotemporal variability of walking and running patterns across a range of speeds, and b) how swiftly gait patterns are adapted to increasing gait speed during the walk-to-run transition. Forty-six adolescents (10-12-year-olds, n = 17; 13-14-year-olds, n = 12; and 15-17-year-olds, n = 17) and 12 young adults completed an incrementally ramped treadmill test (+0.2 km·h-1 every 30 s) to determine the preferred transition speed (PTS) during a walk-to-run transition. Age-related differences in the variability of stride lengths and stride durations were assessed across 4 speeds (self-selected walking speed, PTS - 0.06 m·s-1, PTS + 0.06 m·s-1, PTS + 0.83 m·s-1). Repeated measures ANOVAs (p < 0.05) compared coefficients of variation for these spatiotemporal parameters, while a one-way ANOVA compared the numbers of gait transitions and speed increments used to identify PTS between the adolescent groups and young adults. Compared to adults, 10-12yo exhibited more spatiotemporal variability during all gait conditions, while 13-17yo only exhibited more variability at PTS + 0.06 m·s-1. No age-dependent pattern was observed in PTS values, but 10-12yo completed more gait transitions over more speed increments than 15-17yo and adults. The development of mature gait patterns is thus a progressive process, with walking maturing at an earlier age than running. As 10-12yo were unable to swiftly adapt gait patterns to the changing task demands, their control mechanisms of gait may not have fully matured yet.

Multifractal Analysis Differentiates Postural Sway in Obese and Nonobese Children.

Multifractal analyses have been used in recent years as a way of studying balance, with the goal of understanding the patterns of movement of the center of pressure at different spatial scales. A multifractal detrended fluctuation analysis was used to compare obese and nonobese children to investigate the cause of previously demonstrated deficiencies in balance for obese children. Twenty-two children (11 obese and 11 nonobese), aged 8-15 years, performed 30-s trials of bilateral static balance on a plantar pressure distribution measuring device. Both the obese and nonobese groups demonstrated greater persistence for small fluctuations, but the effect was greater in the obese group. This was particularly evident with the eyes closed, where significant differences between the obese and nonobese were observed for small fluctuations. These results demonstrate that balance deficiencies in obese children may be the result of decreased proprioceptive abilities in obese children.