Diane L. Riddiford-Harland

Upper and lower limb functionality: Are these compromised in obese children?

OBJECTIVE The aim of this study was to investigate the effects of obesity on upper and lower limb functional strength and power in children, and to determine whether the ability to perform the daily activity of rising from a chair was compromised in obese children. It was hypothesised that obese children would display less upper and lower limb functionality compared to their non-obese counterparts. METHODS Upper and lower limb strength and power of 43 obese children (aged 8.4 +/- 0.5 y, BMI 24.1 +/- 2.3 kg/m(-2)) and 43 non-obese controls (aged 8.4 +/- 0.5 y, BMI 16.9 +/- 0.4 kg/m(-2)) were assessed using age-appropriate field-based tests: arm push/pull ability; basketball throw; vertical jump (VJ), and standing long jump (SLJ) performance. Functional lower limb strength was assessed for 13 obese and 13 non-obese children by quantifying their chair rising ability. RESULTS Although obese children displayed significantly greater upper limb push (9.3 +/- 2.3 kg) and pull strength (9.6 +/- 3.0 kg) than their non-obese peers (push: 8.8 +/- 2.2 kg; pull: 8.8 +/- 2.3 kg; p < or = 0.05), their VJ (22.1 +/- 4.3 cm) and SLJ (94.6 +/- 12.8 cm) performance was significantly impaired relative to the non-obese children (VJ: 24.7 +/- 4.0 cm; SLJ: 101.7 +/- 14.0 cm; p < or = 0.05). Obese children spent significantly more time during all transfer phases of the chair rising task, compared to the non-obese children. CONCLUSIONS Lower limb functionality in young obese children is impeded when they move their greater body mass against gravity.

Are the feet of obese children fat or flat? Revisiting the debate

Objective:There is debate as to the effects of obesity on the developing feet of children. We aimed to determine whether the flatter foot structure characteristic of obese primary school-aged children was due to increased medial midfoot plantar fat pad thickness (fat feet) or due to structural lowering of the longitudinal arch (flat feet).Methods and procedures:Participants were 75 obese children (8.3±1.1 years, 26 boys, BMI 25.2±3.6 kg m−2) and 75 age- and sex-matched non-obese children (8.3±0.9 years, BMI 15.9±1.4 kg m−2). Height, weight and foot dimensions were measured with standard instrumentation. Medial midfoot plantar fat pad thickness and internal arch height were quantified using ultrasonography.Results:Obese children had significantly greater medial midfoot fat pad thickness relative to the leaner children during both non-weight bearing (5.4 and 4.6 mm, respectively; P<0.001) and weight bearing (4.7 and 4.3 mm, respectively; P<0.001). The obese children also displayed a lowered medial longitudinal arch height when compared to their leaner counterparts (23.5 and 24.5 mm, respectively; P=0.006).Conclusion:Obese children had significantly fatter and flatter feet compared to normal weight children. The functional and clinical relevance of the increased fatness and flatness values for the obese children remains unknown.

Medial midfoot fat pad thickness and plantar pressures: are these related in children?

OBJECTIVE Previous research has shown that obese children have thicker plantar fat pads compared to non-obese children. As it is uncertain how this thickness influences dynamic foot function, this study aimed to investigate the relationship between dynamic plantar pressures generated beneath the feet of school-aged children and their medial midfoot fat pad thickness measures. METHODS AND PROCEDURES Height and weight were measured, and BMI calculated, for 252 children aged 6.0-9.9 y (mean ? SD 8.1 ? 1.0 y, 112 boys). Medial midfoot plantar fat pad thickness was quantified using ultrasonography and dynamic plantar pressure distributions were measured using a pressure platform. Data were correlated to establish the strength of the relationships among BMI, plantar fat pad thickness and medial midfoot plantar pressures. RESULTS Both medial midfoot plantar fat pad thickness and medial midfoot plantar pressure were significantly correlated with BMI (r = 0.401, P < 0.001 and r = 0.465, P < 0.001, respectively). Although medial midfoot plantar pressure significantly correlated with midfoot plantar fat pad thickness during non-weight bearing (r = 0.294, P < 0.001) and weight bearing (r = 0.289, P < 0.001), the strength of the relationships was low. CONCLUSION Additional medial midfoot fat padding in obese school-aged children appears to reflect their excess body mass rather than an adaptation to cushion pressures associated with this increased body mass. Further investigation is required to identify probable short- and long-term functional limitations resulting from increased pressures generated beneath the feet of obese children when walking.

Lower activity levels are related to higher plantar pressures in overweight children

PURPOSE This study aimed to establish whether the peak plantar pressures generated by overweight and obese school-age children during walking were associated with their objectively measured physical activity. METHODS Physical activity levels of a subset of 73 overweight/obese children from a randomized controlled trial (mean ± SD: age, 8.3 ± 1.1 yr; 47 girls; body mass index z-score, 2.7 ± 0.7) were objectively measured using accelerometers. Plantar pressure distributions were also quantified as the participants walked over a pressure platform. Pearson product moment correlation coefficients were calculated to determine the strength of the relations between the peak plantar pressures generated during walking and the physical activity levels for overweight/obese children. RESULTS Peak pressures generated beneath the forefoot during walking were inversely correlated with time spent in different intensity levels of physical activity. Moderate-intensity (r = -0.321, P = 0.007), vigorous-intensity (r = -0.326, P = 0.006), and moderate- to vigorous-intensity (r = -0.342, P = 0.004) physical activity were significantly correlated with middle forefoot pressure and with lateral forefoot pressure (r = -0.248, P = 0.040; r = -0.264, P = 0.028; r = -0.267, P = 0.027, respectively). Lateral midfoot (r = -0.244, P = 0.044) and second toe (r = 0.227, P = 0.021) pressure were also significantly correlated with vigorous-intensity activity. CONCLUSIONS Those children who generated higher pressures beneath their forefoot and midfoot during walking had lower levels of physical activity. Further research is required to determine the long-term effects of excessive body mass on participation in physical activity and whether the walking plantar pressure patterns associated with reduced physical activity are related to foot pain or discomfort.

Effects of wearing gumboots and leather lace-up boots on lower limb muscle activity when walking on simulated underground coal mine surfaces

This study aimed to investigate the effects of wearing two standard underground coal mining work boots (a gumboot and a leather lace-up boot) on lower limb muscle activity when participants walked across simulated underground coal mining surfaces. Quadriceps (rectus femoris, vastus medialis, vastus lateralis) and hamstring (biceps femoris, semitendinosus) muscle activity were recorded as twenty male participants walked at a self-selected pace around a circuit while wearing each boot type. The circuit consisted of level, inclined and declined surfaces composed of rocky gravel and hard dirt. Walking in a leather lace-up boot, compared to a gumboot, resulted in increased vastus lateralis and increased biceps femoris muscle activity when walking on sloped surfaces. Increased muscle activity appears to be acting as a slip and/or trip prevention strategy in response to challenging surfaces and changing boot features.

Work boot design affects the way workers walk: A systematic review of the literature

Safety boots are compulsory in many occupations to protect the feet of workers from undesirable external stimuli, particularly in harsh work environments. The unique environmental conditions and varying tasks performed in different occupations necessitate a variety of boot designs to match each workers occupational safety and functional requirements. Unfortunately, safety boots are often designed more for occupational safety at the expense of functionality and comfort. In fact, there is a paucity of published research investigating the influence that specific variations in work boot design have on fundamental tasks common to many occupations, such as walking. This literature review aimed to collate and examine what is currently known about the influence of boot design on walking in order to identify gaps in the literature and develop evidence-based recommendations upon which to design future research studies investigating work boot design.

Does participation in a physical activity program impact upon the feet of overweight and obese children

OBJECTIVES To investigate the effect of a weight-bearing physical activity program on foot structure and plantar pressures generated by overweight/obese children. DESIGN Descriptive study. METHODS Measurements were collected for a sample of children participating in an obesity treatment trial (mean±SD 8.5±1.1 y, 29.4% boys, 2.63±0.61 body mass index z-score). Children were randomised to physical activity (physical activity; n=24) and no physical activity (no physical activity; n=10) groups. Foot structure was characterised using anthropometry, an emed(®) AT-4 system quantified pressure distributions and Actigraph accelerometers objectively measured physical activity. RESULTS After 6 months there was a significant decrease in body mass index z-score (physical activity: p=0.002, no physical activity: p<0.001), an increase in foot length (physical activity: p<0.001, no physical activity: p<0.001) and foot height (physical activity: p<0.001, no physical activity: p=0.008), although no change in physical activity. Pressure-time integrals increased after 6 months (lateral midfoot; physical activity: p=0.036, medial forefoot; physical activity: p=0.002, no physical activity: p=0.013, middle forefoot; physical activity: p=0.044, lateral forefoot; physical activity: p=0.043) but there were no between-group differences in plantar pressures after the physical activity program. CONCLUSIONS Although changes to foot structure and function in overweight/obese children could not be attributed to participating in the physical activity program, their developing feet may still be at risk of pain and discomfort due to higher plantar pressures and pressure-time integrals. Further research investigating ways to reduce plantar pressures generated by overweight/obese children while they are physically active is warranted.

The three-dimensional shapes of underground coal miners’ feet do not match the internal dimensions of their work boots

Abstract Mining work boots provide an interface between the foot and the ground, protecting and supporting miners’ feet during lengthy coal mining shifts. Although underground coal miners report the fit of their work boots as reasonable to good, they frequently rate their boots as uncomfortable, suggesting that there is a mismatch between the shape of their feet and their boots. This study aimed to identify whether dimensions derived from the three-dimensional scans of 208 underground coal miners’ feet (age 38.3 ± 9.8 years) differed from the internal dimensions of their work boots. The results revealed underground coal miners wore boots that were substantially longer than their feet, possibly because boots available in their correct length were too narrow. It is recommended boot manufacturers reassess the algorithms used to create boot lasts, focusing on adjusting boot circumference at the instep and heel relative to increases in foot length. Practitioner Summary: Fit and comfort ratings suggest a mismatch between the shape of underground coal miners’ feet and their boots exists. This study examined whether three-dimensional scans of 208 miners’ feet differed from their boot internal dimensions. Miners wore boots substantially longer than their feet, possibly due to inadequate width.

Scoring Analysis of Manoeuvres Performed in Elite Male Professional Surfing Competitions

PURPOSE To investigate the influence of turns, tube rides, and aerial maneuvers on the scores awarded in elite mens professional surfing competitions. The successful completion rate and scores associated with different aerial variations were also investigated. METHODS Video recordings from all 11 events of the 2015 World Surf League mens world championship tour were viewed to classify maneuvers performed by the competitors on each wave as turns, tube rides, and aerials. A 2-way ANOVA was used to determine any main effect or interaction of maneuver type or event location on the wave scores. A 1-way ANOVA was used to determine any main effect of aerial type on successful completion rate. RESULTS Aerial maneuvers were scored significantly higher than tube rides and turns. A significant main effect existed for maneuver and completion rate. Aerial maneuvers had the lowest completion rate, 45.4%. During the finals series (quarterfinals, semifinals, and finals heats) aerial-maneuver completion rate was higher, 55.4%. The frontside air reverse was the most commonly performed maneuver and received an average score of 6.77 out of 10. CONCLUSION Professional surfers can optimize their potential single-wave scores during competition by successfully completing aerial maneuvers. However, aerial maneuvers continue to be a high-risk maneuver with a significantly lower completion rate. Our findings suggest that surfers should aim to improve their aerial-maneuver completion rate via surf practice or land-based training drills.

Excessive Weight Bearing Compromises Foot Structure and Function Across the Lifespan

The base of support for the musculoskeletal system during most physical activities is the feet. Feet are highly unique and flexible structures, which are required to perform extremely diverse functions, particularly during weight-bearing tasks. Although feet that are structurally sound can usually perform tasks of daily living with ease, deviations from normal foot structure or alignment can compromise foot function and, in turn, cause discomfort or pain. Extensive research has confirmed that obesity negatively affects foot structure and function. Obese individuals have been found to have broader, thicker and flatter feet; generate significantly higher dynamic plantar pressures; and alter their foot mechanics during walking relative to their non-overweight counterparts. The need for overweight and obese individuals to bear excess body mass has also been associated with the development of musculoskeletal pain and discomfort in the feet, which can be severe enough to limit these individuals from participating in activities of daily living, work and recreation. As this can perpetuate the cycle of obesity, the compromised foot structure of obese individuals is deemed a major health issue. In this chapter, we review the effects of bearing excessive body mass on foot structure and function across a lifespan and, where possible, highlight the impact of this excessive weight bearing on the ability of individuals to perform activities of daily living. Based on the studies reviewed we recommend that evidence-based interventions be designed to reduce excess fat mass in overweight and obese individuals, focussing on non-weight bearing activities to relieve loading of their foot structures and, in turn, improve the quality of life of these individuals.