Mechanography in childhood: references for force and power in counter movement jumps and chair rising tests.

OBJECTIVE: We sought to procure age- and gender- related reference data and study the characteristics of body weight related peak force (pFrel), body mass related peak power (pPrel) for counter movement jumps (single two-legged jumps, s2LJ) and chair rising tests (CRT) in children. METHODS: We examined 868 healthy participants (436 female) aged 3 to 19 years. Weight-related results of the s2LJ and CRT Mechanography parameters were reported. RESULTS: pPrel during s2LJ (pPrel(s2LJ)) increased linearly with age for males age 5 to 19 and female age 5 to 11 at a rate of 4.6 W/kg per year. pPrel(s2LJ) for females age 12 to 19 increased only by 2.5 W/kg. CRT time per repetition was 1.065 s, independent of age and gender. pPrel per body mass during the rise phase (pPrel(CRT)) showed similar but smaller age and gender relations as peak power during s2LJ. pFrel was 2.5 g (multiples of earth's gravity) for s2LJ and 1.5 g for CRT. CONCLUSION: This data from normal children from a healthy Caucasian population provide reference values for tests that reflect everyday motor function.

Mechanography in childhood: references for grip force, multiple one-leg hopping force and whole body stiffness.

OBJECTIVE: We sought to study and procure reference values for weight-related maximum isometric grip force (MIGF), maximum voluntary force in relation to body weight (Fmvrel) and peak whole body stiffness (pKwb) in multiple one-legged hopping (m1LH) in childhood. METHODS: We examined 868 children and adolescents (436 female) aged 3 to 19 yrs. Weight related results are reported as multiples of earth's gravity (g). RESULTS: MIFG and Fmv(m1LH) are highly linearly correlated with body weight. After adjustment for weight, mean Fmvrel(m1LH) increases from the age of 3 to 6 yrs, then remains at 3.33 g (SD 0.31 g) between 6 and 19 yrs, independent of age and gender. The difference between legs decreases from 10% at 3 yrs to a constant 5.5% after the age of 7 yrs. Weight-adjusted MIGF also increases steeply from 3 to 6 yrs, then shows a further linear, less steep increase - in males through to age 19 yrs while females show a near-standstill after the age of 12 yrs. pKwb(m1LH) increases from the age of 7 yrs. CONCLUSION: This data from normal children from a healthy Caucasian population provide a reference for tests of motor function.

Vibration or balance training on neuromuscular performance in osteopenic women.

Maintaining neuromuscular function in older age is an important topic for aging societies, especially for older women with low bone density who may be at risk of falls and bone fracture. This randomized controlled trial investigated the effect of resistive exercise with either whole-body vibration training (VIB) or coordination/balance training (BAL) on neuromuscular function (countermovement jump, multiple 1-leg hopping, sit-to-stand test). 68 postmenopausal women with osteopenia or osteoporosis were recruited for the study. 57 subjects completed the 9-month, twice weekly, intervention period. All subjects conducted 30 min of resistance exercise each training day. The VIB-group performed additional training on the Galileo vibration exercise device. The BAL-group performed balance training. An "intent-to-treat" analysis showed greater improvement in the VIB-group for peak countermovement power (p=0.004). The mean [95% confidence interval] effect size for this parameter was a + 0.9[0.3 to 1.5] W/kg greater change in VIB than BAL after 9 months. In multiple 1-leg hopping, a significantly better performance in the VIB-group after the intervention period was seen on a "per-protocol" analysis only. Both groups improved in the sit-to-stand test. The current study provides evidence that short-duration whole-body vibration exercise can have a greater impact on some aspects of neuromuscular function in post-menopausal women with low bone density than proprioceptive training.

Vitamin D status and muscle function in children with neurofibromatosis type 1 (NF1).

OBJECTIVES: The aim of this cross-sectional study was to assess the vitamin D status and muscle function in children with NF1 compared with their unaffected siblings. METHODS: NF1 children between 5 and 18 years of age and who had at least one unaffected sibling were identified. Serum concentrations of 25-hydroxyvitamin D (25(OH)D), calcium, inorganic phosphate, alkaline phosphate, parathyroid hormone and 1,25-dihydroxyvitamin D were measured. The Leonardo Mechanography Ground Reaction Force Platform (GRFP) was used to measure EFI, jump power, force and height. RESULTS: There was no significant difference in 25(OH)D between NF1 subjects and unaffected siblings. Relative jump power and force were found to be significantly different. The adjusted means (95% confidence limits) of non-NF1 and NF1 children for relative jump power (W/kg), controlling for body mass and age, were 37.31 (34.14, 40.49) and 32.51 (29.34, 35.68), respectively (P=0.054); and force (N/kg), controlling for body mass, age and gender, were 25.79 (24.28, 27.30) and 21.12 (19.61, 22.63), respectively (P<0.0001). Jumping parameters were not related to serum 25(OH)D. CONCLUSIONS: There was no significant relationship between vitamin D status and NF1 status in children. NF1 children had significantly impaired jumping power and force, when compared to their unaffected siblings.

Bone density and neuromuscular function in older competitive athletes depend on running distance.

UNLABELLED: Individuals who are involved in explosive sport types, such as 100-m sprints and long jump, have greater bone density, leg muscle size, jumping height and grip strength than individuals involved in long-distance running. INTRODUCTION: The purpose of this study is to examine the relationship between different types of physical activity with bone, lean mass and neuromuscular performance in older individuals. METHODS: We examined short- (n = 50), middle- (n = 19) and long-distance (n = 109) athletes at the 15th European Masters Championships in Poznan, Poland. Dual X-ray absorptiometry was used to measure areal bone mineral density (aBMD) and lean tissue mass. Maximal countermovement jump, multiple one-leg hopping and maximal grip force tests were performed. RESULTS: Short-distance athletes showed significantly higher aBMD at the legs, hip, lumbar spine and trunk compared to long-distance athletes (p ≤ 0.0012). Countermovement jump performance, hop force, grip force, leg lean mass and arm lean mass were greater in short-distance athletes (p ≤ 0.027). A similar pattern was seen in middle-distance athletes who typically showed higher aBMD and better neuromuscular performance than long-distance athletes, but lower in magnitude than short-distance athletes. In all athletes, aBMD was the same or higher than the expected age-adjusted population mean at the lumbar spine, hip and whole body. This effect was greater in the short- and middle-distance athletes. CONCLUSIONS: The stepwise relation between short-, middle- and long-distance athletes on bone suggests that the higher-impact loading protocols in short-distance disciplines are more effective in promoting aBMD. The regional effect on bone, with the differences between the groups being most marked at load-bearing regions (legs, hip, spine and trunk) rather than non-load-bearing regions, is further evidence in support of the idea that bone adaptation to exercise is dependent upon the local loading environment, rather than as part of a systemic effect.

Effects of jumping exercise on maximum ground reaction force and bone in 8- to 12-year-old boys and girls: a 9-month randomized controlled trial.

OBJECTIVES: To assess adaptations of the lower leg muscle-bone unit in 8- to 12-year-old children following a randomized controlled jumping exercise intervention for 9 months. METHODS: Twelve boys and 10 girls (INT) performed a supervised jumping protocol during the first 10 min of their regularly scheduled physical education class twice a week, while 11 boys and 12 girls (CON) completed the regular curriculum. We assessed maximum voluntary ground reaction force during multiple one-legged hopping (F(m1LH)), and tibial bone strength/geometry by peripheral quantitative computed tomography (pQCT) at the 4-, 14-, 38- and 66%-site pre, intermediate, and post intervention. RESULTS: Whether increases in F(m1LH) (+2.1% points, P= 0.752), nor changes in bone strength/geometry (+1 to +3% points, 0.169

A randomized, controlled trial of vitamin D supplementation upon musculoskeletal health in postmenarchal females.

CONTEXT: There has been a resurgence of vitamin D deficiency rickets throughout the developed world, with infants and adolescents being primarily affected. Adolescence is a crucial period for muscle and bone mineral accumulation. OBJECTIVE: The aim was to determine the effect of vitamin D supplementation on the adolescent musculoskeletal system. DESIGN AND SETTING: We conducted a community-based, double-blind, randomized controlled trial in a secondary school. PARTICIPANTS: Postmenarchal 12- to 14-yr-old females participated in the trial. Ninety-nine were screened, 73 were included in randomized controlled trial, and 69 completed the trial. There were no adverse events. INTERVENTION: Four doses of 150,000 IU vitamin D(2) (ergocalciferol) were given over 1 yr. MAIN OUTCOME MEASURES: Dual-energy x-ray absorptiometry, peripheral quantitative computed tomography, and jumping mechanography were used. RESULTS: At follow-up, 25-hydroxyvitamin D [25(OH)D] status was 56.0 ± 8.9 nmol/liter in the intervention group and 15.8 ± 6.6 nmol/liter in controls. There were no effects of supplementation on bone; however, for muscle function, efficiency of movement improved in the vitamin D-treated group. There was an interaction between baseline 25(OH)D concentration and response to vitamin D supplementation for muscle jump velocity. CONCLUSIONS: Despite improvements in 25(OH)D status, treatment with vitamin D(2) was not shown to increase mineral accretion, bone geometry or strength, muscle force, or power. There were greater increases in jump velocity in girls with the lowest baseline 25(OH)D concentrations. Lack of effect of intervention after the period of peak mineral and muscle mass accretion suggests that earlier action is required.

Whole body vibration in cystic fibrosis--a pilot study.

INTRODUCTION: In cystic fibrosis (CF), bone mass deficits as well as a lack of muscle mass and force have been described. The bone mass deficits are thought to be at least in part secondary to the reduced muscle mass. Whole body vibration has recently been suggested as an effective technique to increase muscle force and power. The aim of this pilot study was to evaluate the compliance and safety of a side-alternating, whole body vibration platform in patients with CF and to assess its effects on muscle force, muscle power, bone mass and lung function. PATIENTS AND METHODS: Eleven adult CF patients participated in a six-months home-based training programme on a whole body vibration platform. Muscle force and power were assessed with three standard manoeuvres on a ground reaction force plate at regular intervals. Bone densitometry was performed at the spine, the radius and the tibia using quantitative computerized tomography. RESULTS: Regular cardiovascular monitoring did not show any critical drop in oxygen saturation or blood pressure. Lung function remained relatively constant with a median FEV1 change [% of norm] of -3.1% (range -7-20). Trabecular density at the spine and parameters of bone density and geometry at the radius and tibia did not show consistent changes. A median decrease of -0.3% (-31.0-17.9) for muscle force and a median increase of 4.7% (-16.4-74.5) for muscle power and 6.6% (-0.9-48.3) for velocity was noted in the two-leg jump. In the one-leg jump, a median increase of 6.7% (-8.5-24.3) for muscle force was measured. CONCLUSIONS: Whole body vibration was well tolerated in the majority of the study participants. Most patients were able to increase peak force in the one-leg jump. In the two-leg jump, velocity and muscle power increased with equal or decreased muscle force. This may indicate an improvement in neuromuscular and intramuscular co-ordination (and therefore efficiency) with less muscle force necessary to generate the same power.

[Does the orientation of the IOL in the eye play a role? Imaging quality of foldable intraocular lenses measured utilizing point spread function (PSF-measurement) and scanning electron microscopy cross-sectional images]. / Spielt die Orientierung einer IOL im Auge eine Rolle? Abbildungseigenschaften von faltbaren Intraokularlinsen gemessen mittels Analyse der Punktbildfunktion (PSF-Messungen) und rasterelektronenmikroskopischen Querschnittsaufnahmen.

BACKGROUND: Foldable intraocular lenses (IOLs) are established in ophthalmic surgery and increasingly more complex geometries are available. This study investigates different designs of the optics of the IOL as well as the imaging quality of these optics utilizing electron microscopic photographs and mathematical approximations. METHOD: Included in this study were two different lens powers of common IOLs (+ 13 D and + 26 D). All studied IOLs were processed depending upon their water content: Aqueous IOLs with up to 25 % water content were fixed with 2.5 % glutaraldehyde in 0.1 M phosphate buffer (mPP), and then contrasted with 2 % OsO (4) and processed in an alcohol series of 30 - 100 % propanol. Subsequently, the IOLs were transferred into EPON (epoxy resin) and polymerization took place at 60 degrees C. After hardening, the samples were cut out with a leaves saw and divided into halves. Afterwards these were polished with glass and diamond knifes at the ultramicrotom (Ultracut, Rückert-Jung). After coal vaporization measurement took place in the scanning electron microscope (DSM 962, Zeiss). In the case of dry stored IOLs, the samples were sputtered with Au-Pd 20 nm and afterwards measurement was performed as described above. The measurement of the optical imaging quality was performed with correctly and inversely oriented IOLs according to the standard EN ISO 11979 -- 2 by means of a measuring system which works on the basis of the point spread function (PSF) and/or the modulation transfer function (MTF). From this the Strehl ratio was computed in each case. RESULTS: Utilizing a correlation of the electron microscopic investigation of the optics of different IOLs with their imaging quality (Strehl ratio), we were able to show that the optical design of the IOL has substantial influence on the imaging quality of an intraocular lens. In particular, with non-symmetrical designs of the optics (e. g., AR40 e; AMO) the orientation of an IOL in the eye is crucial; i. e., the Strehl ratio increased thereby from 0.68 to 0.87. CONCLUSIONS: The design of asymmetrical optics is crucial and much attention should be paid to the fact that the imaging quality can substantially be affected. A correct orientation of the lens within the eye is very important with these asymmetrical optics.

Polarimetric methods for measurement of intra ocular glucose concentration.

Due to the increasing lifespan in the industrialized world the number of senior Diabetes patients is growing rapidly. Using non-invasive techniques, measurements of the blood sugar level could be done more frequently and hence diagnosis as well as therapy of type II Diabetes Mellitus can be improved especially for this group of senior patients. Especially polarimetric techniques measuring at the human eye offer promising properties for non-invasive and painless measurement. This article discusses different approaches for utilizing the polarizing properties of the Aqueous Humour (AH) for quantitative glucose measurements.