Effect of a Rehabilitation Program Including Home-Based Vibration-Assisted Therapy on Gait Parameters in Children with Cerebral Palsy.

OBJECTIVES: The aim of the present study was to examine the effects of a rehabilitation program combined with a home-based vibration-assisted therapy on gait parameters in children with cerebral palsy (CP). METHODS: In a retrospective study, 180 children, 101 boys and 79 girls, (mean age 7.2 ± 3.3 years) with CP at Gross Motor Function Classification System (GMFCS) Level I and Level II were examined using gait analyses with the Leonardo Mechanograph® Gangway at three measurement points. The measurements were conducted before (M0) and after a six-month rehabilitation period (M6), as well as 12 months after the commencement of rehabilitation (M12). The difference between measurement points M6-M0 (treatment interval) and M12-M6 (follow-up interval) were compared, and significance was determined using the Wilcoxon test. RESULTS: Children with CP at GMFCS Level I and II demonstrated a significant improvement in gait efficiency (pathlength/distance M6-M0: -0.053 (SD 0.25) vs M12-M6: -0.008 (0.36), p=0.038). There were no significant difference in change of mean velocity and average step length between M6-M0 and M12-M6 (p=0.964 and p=0.611). CONCLUSIONS: The rehabilitation program seems to enhance gait efficiency in children with CP. German Clinical Trial Registry: DRKS0001131 at www.germanctr.de.

Gender-specific Indian Paediatric and Adult Reference Data for Muscle Function Parameters Assessed Using Jumping Mechanography.

OBJECTIVE: To establish age and gender-specific paediatric and adult reference data for muscle function parameters assessed using Jumping Mechanography in the Indian population. METHODS: 2056 healthy individuals (1068 males), aged 5 to 60 years, performed 2 tests on a force platform (Leonardo Mechanograph, Novotec). Maximum power (Pmax) was assessed by single two legged jump and maximum force (Fmax) by multiple one legged hopping. LMS method was used to generate age and gender-specific reference curves for 5 - 20y group and mean ± SD and median ± IQR are presented for 21 - 60y group. RESULTS: In 5 - 20y group, Pmax and Fmax increased with age while in 21 - 60y group, the parameters declined with age. Females had lower Pmax values than males, consistently through all age groups. In children <15y, there were no intergender differences in Fmax, however, in further age groups, females had lower Fmax (p<0.001). Our participants showed lower Pmax and Fmax when compared with machine reference data based on German population (p<0.001). CONCLUSION: We present ethnicity-specific reference values for muscle function by Jumping Mechanography. These values are intended to help in clinical assessment of muscle function of Indian population and to identify those at risk of poor muscle function.

Mechanography in children: pediatric references in postural control.

OBJECTIVE: To establish pediatric age- and sex-specific references for measuring postural control with a mechanography plate in a single centre, prospective, normative data study. METHODS: 739 children and adolescents (396 male/343 female) aged 4 to 17 years were studied. Each participant completed the following test sequence three times: Romberg, semi-tandem, tandem, each with eyes open and closed, and a one-leg stand with eyes open, and a single two-legged jump. Normal ranges were determined based on percentile calculations using the LMS method. Results from the two-legged jump were compared to a reference population the single two-legged jump (s2LJ) assessment in 2013. RESULTS: 38 different equilibrium parameters calculated were analysed. Of all parameters Path Length, vCoFmean, Equilibrium Score and Sway Angle showed a low variation within the same age group but high dependency on age and were thus chosen for automated balance assessment. CONCLUSION: Standard values of postural control in healthy children derived from automated balance testing using a mechanography plate were successfully acquired and a subset of parameters for automated balance assessment identified.

Determinants of muscle power and force as assessed by Jumping Mechanography in rural Indian children.

OBJECTIVES: To: 1. Assess muscle function (MF) of rural Indian children (6-11y, n=232), using Jumping Mechanography (JM) and hand dynamometer, 2. Investigate gender differences, 3. Identify determinants of MF. METHODS: Data on anthropometry, muscle mass%, diet, physical activity, sunlight exposure, MF (maximum relative power Pmax/mass, maximum relative force Fmax/BW by JM; relative grip strength (RGS) by hand dynamometer) were collected. Pearson's correlation and hierarchical linear regression was performed. RESULTS: Pmax/mass, Fmax/BW and RGS of the group were 31.7±5.0W/kg, 3.0±0.3 and 0.4±0.1 (mean±SD), respectively. The Pmax/mass Z-score was -1.1±0.9 and Fmax/BW Z-score was -0.9±1 (mean±SD) which was significantly lower than the machine reference data (p<0.05). Positive association of muscle mass% and protein intake was observed with all MF parameters and moderate+vigorous physical activity with Fmax/BW (p<0.05). Determinants of MF identified through regression for Pmax/mass were age (ß=1.83,95% CI=0.973 - 2.686), muscle mass% (ß=0.244,95% CI=0.131-0.358) and protein intake (ß=3.211,95% CI=1.597-4.825) and for Fmax/BW was protein intake (ß=0.130,95% CI=0.023-0.237) (p<0.05). Male gender was a positive predictor of having higher Pmax/mass (ß=1.707,95% CI=0.040-3.373) (p<0.05). CONCLUSION: MF was lower than in western counterparts. To optimize MF of rural Indian children, focus should be on improving muscle mass, ensuring adequate dietary protein, and increasing physical activity, especially in girls.

Longitudinal changes in muscle power compared to muscle strength and mass.

OBJECTIVES: The study reports longitudinal changes in grip strength, muscle mass and muscle power of lower extremities. The aim is to identify early muscular changes to improve the diagnosis and treatment of sarcopenia. METHODS: Grip strength was measured by hand dynamometer, muscle mass by dual-energy X-ray absorptiometry and muscle power by performing a chair rise test and two-leg jumps (2LJP) on the Leonardo Mechanograph®. Longitudinal changes were analysed using paired t-tests by age group and sex. Differences between groups in terms of the annual change were tested by Analysis of Variance and the Dunnett's test. Comparisons between the variables were performed using one sample t-tests. RESULTS: Six-year changes were determined in 318 randomly selected healthy participants aged 20-90 years from Berlin. 2LJP declined significantly earlier in 20-39 years old women (-3.70 W/kg) and men (-5.97 W/kg, both p<0.001). This is an absolute annual decline of -0.46 W/kg in females and -0.75 W/kg in males. In the oldest age group, 2LJP showed the highest absolute annual loss with -0.99 W/kg in women and -0.88 W/kg in men. 2LJP was significantly different compared to all variables of muscle mass and strength (p<0.01). CONCLUSIONS: The results underline the importance of assessing muscle power using 2LJP during aging.

Association between sarcopenia, physical performance and falls in patients with rheumatoid arthritis: a 1-year prospective study.

BACKGROUND: Patients with rheumatoid arthritis (RA) are at increased risk of falls and fractures. Sarcopenia occurs more frequently in RA patients due to the inflammatory processes. Early diagnosis and prevention programmes are essential to avoid serious complications. The present study aims to identify risk factors for falls related to sarcopenia and physical performance. METHODS: In a 1-year prospective study, a total of 289 patients with RA, ages 24-85 years, were followed using quarterly fall diaries to report falls. At the baseline, medical data such as RA disease duration and Disease Activity Score (DAS28CRP) were collected. Self-reported disability was assessed using the Health Assessment Questionnaire (HAQ). Appendicular skeletal mass was determined by Dual X-ray-Absorptiometry (DXA). Physical performance was evaluated by handgrip strength, gait speed, chair rise test, Short Physical Performance Battery, and FICSIT-4. Muscle mechanography was measured with the Leonardo Mechanograph®. Sarcopenia was assessed according to established definitions by the European Working Group on Sarcopenia in Older People (EWGSOP2) and The Foundation for the National Institutes of Health (FNIH). Univariate and multiple logistic regression analysis were used to explore associations with falling. Receiver-operating characteristics (ROC) were performed, and the area under the curve is reported. RESULTS: A total of 238 subjects with RA completed the 1-year follow-up, 48 (20.2%) experienced at least one fall during the observational period. No association was found between sarcopenia and prospective falls. Age (OR = 1.04, CI 1.01-1.07), HAQ (OR = 1.62, 1.1-2.38), and low FICSIT-4 score (OR = 2.38, 1.13-5.0) showed significant associations with falls. CONCLUSIONS: In clinical practice, a fall assessment including age, self-reported activities of daily life and a physical performance measure can identify RA patients at risk of falling. TRIAL REGISTRATION: The study has been registered at the German Clinical Trials Register and the WHO International Clinical Trials Registry Platform (ICTRP) since 16 March 2017 ( DRKS00011873 ).

Jumping Joints: The Complex Relationship Between Osteoarthritis and Jumping Mechanography.

We investigated the relationship between lower limb osteoarthritis (OA) and muscle strength and power (assessed by jumping mechanography) in UK community-dwelling older adults. We recruited 249 older adults (144 males, 105 females). OA was assessed clinically at the knee according to ACR criteria and radiographically, at the knee and hip, using Kellgren and Lawrence grading. Two-footed jumping tests were performed using a Leonardo Mechanography Ground Reaction Force Platform to assess maximum muscle force, power and Esslinger Fitness Index. Linear regression was used to assess the relationship between OA and jumping outcomes. Results are presented as ß (95% confidence interval). The mean age of participants was 75.2 years (SD 2.6). Males had a significantly higher maximum relative power during lift off (mean 25.7 W/kg vs. 19.9 W/kg) and maximum total force during lift off (mean 21.0 N/kg vs. 19.1 N/kg) than females. In adjusted models, we found significant associations in males between clinical knee OA and maximum relative power [- 6.00 (CI - 9.10, - 2.94)] and Esslinger Fitness Index [- 19.3 (- 29.0, - 9.7)]. In females, radiographic knee OA was associated with total maximum power [- 2.0 (- 3.9, - 0.1)] and Esslinger Fitness Index [- 8.2 (- 15.9, - 0.4)]. No significant associations were observed for maximum total force. We observed significant negative associations between maximum relative power and Esslinger Fitness Index and clinical knee OA in males and radiographic knee OA in females. We have used novel methodology to demonstrate relationships between muscle function and OA in older adults.

Lean mass and lower limb muscle function in relation to hip strength, geometry and fracture risk indices in community-dwelling older women.

In a population-based sample of British women aged over 70 years old, lean mass and peak lower limb muscle force were both independently associated with hip strength and fracture risk indices, thereby suggesting a potential benefit of promoting leg muscle strengthening exercise for the prevention of hip fractures in postmenopausal women. INTRODUCTION: To investigate cross-sectional associations of lean mass and physical performance, including lower limb muscle function, with hip strength, geometry and fracture risk indices (FRIs) in postmenopausal women. METHODS: Data were from the Cohort of Skeletal Health in Bristol and Avon. Total hip (TH) and femoral neck (FN) bone mineral density (BMD), hip geometry and total body lean mass (TBLM) were assessed by dual x-ray absorptiometry (DXA). Finite element analysis of hip DXA was used to derive FN, intertrochanteric and subtrochanteric FRIs. Grip strength, gait speed and chair rise time were measured objectively. Lower limb peak muscle force and muscle power were assessed by jumping mechanography. RESULTS: In total, 241 women were included (age = 76.4; SD = 2.6 years). After adjustment for age, height, weight/fat mass and comorbidities, TBLM was positively associated with hip BMD (ßTH BMD = 0.36, P ≤ 0.001; ßFN BMD = 0.26, P = 0.01) and cross-section moment of inertia (0.24, P ≤ 0.001) and inversely associated with FN FRI (- 0.21, P = 0.03) and intertrochanteric FRI (- 0.11, P = 0.05) (estimates represent SD difference in bone measures per SD difference in TBLM). Lower limb peak muscle force was positively associated with hip BMD (ßTH BMD = 0.28, P ≤ 0.001; ßFN BMD = 0.23, P = 0.008) and inversely associated with FN FRI (- 0.17, P = 0.04) and subtrochanteric FRI (- 0.18, P = 0.04). Associations of grip strength, gait speed, chair rise time and peak muscle power with hip parameters were close to the null. CONCLUSIONS: Lean mass and lower limb peak muscle force were associated with hip BMD and geometrical FRIs in postmenopausal women. Leg muscle strengthening exercises may therefore help prevent hip fractures in older women.

Normative-referenced percentile values for physical fitness among Canadians.

BACKGROUND: This study developed age- and sex-specific normative-referenced percentile values for five physical fitness tests across a wide age range of Canadians, using a nationally representative sample. DATA AND METHODS: The data are from 5,188 Canadians (50.1% female) and were collected as part of cycle 5 of the Canadian Health Measures Survey (2016 to 2017). RESULTS: Males had slightly better cardiorespiratory fitness and substantially better grip strength, jumping height and jumping power scores than females, whereas females had better sit-and-reach flexibility. Among females, there were pronounced increases in jumping height (P50: 25%) and jumping power (P50: 58%) between ages 8 and 13, and in grip strength (P50: 193%) between ages 6 and 19. Performance gradually declined with age, beginning in adolescence for jumping ability and at approximately age 35 for grip strength. Among males, there were pronounced increases in jumping height (P50: 69%) and jumping power (P50: 233%) between ages 8 and 20, and in grip strength (P50: 365%) between ages 6 and 20. Performance gradually declined with age, beginning immediately after adolescence for jumping ability and at approximately age 30 for grip strength. Sit-and-reach flexibility remained relatively stable with age in both sexes. Cardiorespiratory fitness scores in both sexes declined steadily with age beginning (generally) at age 8, with a larger decline evident in females until age 18. DISCUSSION: These normative-referenced values for physical fitness could be useful for screening in public health and clinical practice.

Postural control is associated with muscle power in post-menopausal women with low bone mass.

Older women with low bone mass are at higher risk of fracture and there is limited data on what is associated with risk of falls. We found explosive jumping to relate most strongly to postural control. It may be beneficial to include power or speed training into falls prevention programs. INTRODUCTION: Post-menopausal women with low bone mass are at higher risk of bone fractures subsequent to falls. Understanding the correlates of postural control in this collective informs intervention design for falls prevention. METHODS: We examined postural control in single-leg stance on stable and unstable surfaces in 63 community-dwelling post-menopausal women with osteopenia or osteoporosis but without diagnosed neuromuscular, vestibular or arthritic diseases. Postural measures were compared to countermovement jump performance (height, force and power), leg-press strength (10 repetition maximum), calf muscle area and density (via peripheral quantitative computed tomography), body mass, height and age. RESULTS: On step-wise regression, peak countermovement jump power and jump height (p ≤ 0.014), but not jump force, leg-press strength or calf muscle size, were related to postural control in single-leg stance on, respectively, an unstable surface (eyes open) and standing on a stable surface (eyes open). None of the parameters measured were significantly related to the postural control parameters in single-leg stance on a stable surface with eyes closed. With testing on the stable surface, body mass was associated with slow mean centre of pressure movement speed (p ≤ 0.030). CONCLUSIONS: Our findings show that, in post-menopausal women with low bone mass, neuromuscular power is a more important determinant of postural control than muscle strength or size. Our findings provide evidence to support the integration of power or speed training into falls prevention and balance training programs in post-menopausal women with osteopenia and osteoporosis.

Test-retest reliability of jump execution variables using mechanography: a comparison of jump protocols.

Mechanography during the vertical jump may enhance screening and determining mechanistic causes underlying physical performance changes. Utility of jump mechanography for evaluation is limited by scant test-retest reliability data on force-time variables. This study examined the test-retest reliability of eight jump execution variables assessed from mechanography. Thirty-two women (mean±SD: age 20.8 ± 1.3 yr) and 16 men (age 22.1 ± 1.9 yr) attended a familiarization session and two testing sessions, all one week apart. Participants performed two variations of the squat jump with squat depth self-selected and controlled using a goniometer to 80º knee flexion. Test-retest reliability was quantified as the systematic error (using effect size between jumps), random error (using coefficients of variation), and test-retest correlations (using intra-class correlation coefficients). Overall, jump execution variables demonstrated acceptable reliability, evidenced by small systematic errors (mean±95%CI: 0.2 ± 0.07), moderate random errors (mean±95%CI: 17.8 ± 3.7%), and very strong test-retest correlations (range: 0.73-0.97). Differences in random errors between controlled and self-selected protocols were negligible (mean±95%CI: 1.3 ± 2.3%). Jump execution variables demonstrated acceptable reliability, with no meaningful differences between the controlled and self-selected jump protocols. To simplify testing, a self-selected jump protocol can be used to assess force-time variables with negligible impact on measurement error.

Muscle Function in Osteogenesis Imperfecta Type IV.

Results of previous studies suggest that children and adolescents with osteogenesis imperfecta (OI) type IV have muscle force deficits. However, muscle function remains to be objectively quantified in this population. This study aimed to assess upper and lower extremity muscle function in patients with OI type IV. It was carried out in the outpatient department of a pediatric orthopedic hospital; 27 individuals with OI type IV (7-21 years; 13 males), 27 age- and sex-matched individuals with OI type I, and 27 age- and sex-matched controls. Upper extremity muscle force was assessed with hydraulic hand dynamometry, and lower extremity muscle function (peak force per body weight and peak power per body mass) was measured by mechanography through five tests: multiple two-legged hopping, multiple one-legged hopping, single two-legged jump, chair-rise test, and heel-rise test. Upper-limb grip force was normal for patients with OI type IV when compared to height and sex reference data (average z-score = 0.17 ± 1.30; P = 0.88). Compared to age- and sex-matched controls, patients with OI type IV had approximately 30% lower-limb peak force and 50% peak power deficits (P values <0.05). At the lower-limb level, they had a 50% lower peak power than age- and sex-matched patients with OI type I (P < 0.05). Patients with OI type IV have normal upper-limb muscle force but a muscle function deficit at the lower-limb level. These results suggest that lower-limb muscle weakness may contribute to functional deficits in these individuals.

Musculoskeletal system in children and adolescents with inflammatory bowel disease: normal muscle force, decreased trabecular bone mineral density and low prevalence of vertebral fractures.

Low bone mineral density (BMD) and an increased fracture incidence are two extraintestinal complications associated with inflammatory bowel disease (IBD). We aimed to evaluate musculoskeletal traits and assess vertebral fracture (VF) rate in children and adolescents with IBD. Seventy patients with IBD with a median age of 13.8 years were included. The BMD and geometric parameters of the non-dominant tibia were assessed using pQCT. Dynamic muscle functions were evaluated using jumping mechanography. VFs were assessed according to the semiquantitative standardized method by Genant. The muscle functions adjusted for the patients' weight did not differ from the reference population. A low trabecular BMD (Z-score - 1.6; p < 0.001) and cortical thickness (Z-score - 0.7; p < 0.001) were found in children and adolescents with IBD. Conversely, an increased cortical BMD (Z-score 1.1; p < 0.001) was noted. No significant association was found between the 25-OHD serum levels and the bone or muscle measurements. One patient with asymptomatic VF was identified. CONCLUSION: IBD in childhood or adolescents affects bones but not muscles. Bone changes are independent of the 25-OHD serum level. A thoracolumbar spine X-ray should not be routinely recommended in children with IBD. What is Known: • Low bone mineral density and an increased fracture rate are the complications associated with IBD. • Bone strength and structural development is strongly dependent on skeletal muscle stimulation. What is New: • Children with IBD have altered bone density and geometry but normal dynamic muscle functions. • Thoracolumbar spine X-ray should be indicated on an individual basis in children with IBD.

Association of Jumping Mechanography-Derived Indices of Muscle Function with Tibial Cortical Bone Geometry.

Jumping mechanography has been developed to estimate maximum voluntary muscle forces. This study assessed associations of jumping mechanography-derived force and power measurements with tibial cortical bone geometry, compared to other estimates of muscle mass, size, and function. Healthy men (n = 181; 25-45 years) were recruited in a cross-sectional, population-based sibling-pair study. Muscle parameters include isokinetic peak torque of the quadriceps, DXA-derived leg lean mass, mechanography-derived peak jump force and power, and pQCT-derived mid-tibial (66 %) muscle cross-sectional area (CSA). Mid-tibial cortical bone parameters were assessed by pQCT. In age, height, and weight-adjusted analyses, jump force and power correlated positively with cortical bone area, cortical thickness, and polar strength-strain index (SSIp) (ß = 0.23-0.34, p ≤ 0.001 for force; ß = 0.25-0.30, p ≤ 0.007 for power) and inversely with endosteal circumference adjusted for periosteal circumference (ECPC) (ß = -0.16, p < 0.001 for force; ß = -0.13, p = 0.007 for power). Force but not power correlated with cortical over total bone area ratio (ß = 0.25, p = 0.002). Whereas leg lean mass correlated with all cortical parameters except cortical over total bone area ratio (ß = 0.25-0.62, p ≤ 0.004), muscle CSA only correlated with cortical bone area, periosteal circumference, and SSIp (ß = 0.21-0.26, p ≤ 0.001), and quadriceps torque showed no significant correlations with the bone parameters. Multivariate models indicated that leg lean mass was independently associated with overall bone size and strength reflected by periosteal and endosteal circumference and SSIp (ß = 0.32-0.55, p ≤ 0.004), whereas jump force was independently associated with cortical bone size reflected by ECPC, cortical thickness, and cortical over total bone area ratio (ß = 0.13-0.28; p ≤ 0.002). These data indicate that jumping mechanography provides relevant information about the relationship of muscle with bone geometry.

Dynamic Muscle Function Parameters in Indian Children and Adolescents with Type 1 Diabetes Mellitus: A Case-Control Study.

Introduction: Recent evidence reveals that type 1 diabetes mellitus (T1DM) impairs muscle function (MF) in adolescents. However, despite its importance in physical well-being, data on dynamic MF in Indian children and adolescents (C and Y) with T1DM are scarce. We assessed MF using Jumping Mechanography (JM, a measurement method for motion analysis and assessment of muscle power and force). (1) To assess dynamic MF by JM in C and Y with T1DM as compared to healthy controls (2) To determine predictors of MF in children with T1DM. Methods: A cross-sectional observational study on 266 children (133 - T1DM duration >1 year with no known comorbidities + 133 age and gender-matched healthy controls) aged 6-19 years. Anthropometry, body composition, and MF (maximum relative power Pmax/mass, maximum relative force Fmax/BW by JM) were recorded. The lean mass index (LMI) was calculated as lean mass (kg)/height (m2). HbA1c was assessed in T1DM. Independent sample t-test and linear regression were performed. Results: MF parameters (Pmax/mass 33.5 ± 7.2 vs 38.0 ± 8.6 W/kg and Fmax/BW 10.5 ± 2.9 vs 11.4 ± 4.1 N/kg, P < 0.05) were significantly lower in T1DM group vs controls. Positive association of body mass index and LMI with both MF parameters and negative association of insulin requirement and HbA1c with Fmax was observed in T1DM. Predictors of MF identified were MMI (Pmax/mass:b = 1.6,95%CI = 0.6-2.6; Fmax/BW:b =2.0,95%CI = 1.6-2.4) and HbA1c (Pmax/mass:b = -2.1,95%CI = -4.5--0.5; Fmax/BW:b = -1.1,95%CI = -2.0--0.2) (P < 0.05). Conclusion: C and Y with T1DM exhibits compromised muscle function. Poor glycaemic control increases the risk of having decreased MF, irrespective of diabetes duration and may contribute to sarcopenia in adulthood.

Musculoskeletal fitness: relative handgrip strength and vertical jump power from 10 to 18 years old.

Background: There is an increasing consensus on the relevance of musculoskeletal fitness for health throughout the life cycle, requiring evaluation approaches and description of results capable of characterizing different age groups and body sizes. This study aimed to describe the musculoskeletal fitness of young Portuguese people aged 10-18 through handgrip strength (HGS) and vertical jump power (VJP) and investigate differences between the sexes. Methods: The sample included 736 participants (359 girls recruited from schools. HGS (kg) was assessed using a handheld dynamometer, and VJP (W) was assessed using a force platform; both measurements were standardized for body mass. Results: Higher HGS and VJP were observed in boys than in girls from 13 years old (13 years: p ≤ 0.05; 14-18 years: p ≤ 0.001), with no significant differences before this age. The percentile distributions of HGS and VJP are described for each sex using the lambda, mu, sigma (LMS) method. The pattern of development of these variables as a function of age is presented. Conclusions: Handgrip strength and vertical jump power show differences between the sexes from 13 years of age and similar trajectories to populations in other countries in the same age group.

Effect of Yoga or Physical Exercise on Muscle Function in Rural Indian Children: A Randomized Controlled Trial.

BACKGROUND: Synergistic effects of yoga or physical exercise (PE) along with protein supplementation on children's muscle function in rural India have not been studied. Hence, we aimed to study the effect of yoga and PE along with protein supplementation on muscle function in healthy 6- to 11-year-old rural Indian children post 6 months of intervention. METHODS: A randomized controlled trial on 232 children, recruited into 3 groups, each receiving 1 protein-rich ladoo (148 kcal, 7 g protein/40 g ladoo-an Indian sweet snack) daily and performing (1) yoga (n = 78) for 30 minutes 5 times per week, (2) PE (n = 76) for 30 minutes 5 times per week, or (3) control group (n = 78) no additional exercise. Maximum power, maximum voluntary force (Fmax), and grip strength (GS) were measured. Data were analyzed using paired t tests and a 2-way mixed analysis of variance with post hoc Bonferroni adjustment. RESULTS: GS, maximum power, and Fmax within yoga group increased significantly (P < .05) from baseline to endline. GS and Fmax increased significantly within PE group postintervention (P < .001). In controls, GS increased (P < .05) at endline. No significant effect of the intervention was observed on the change in maximum power (P > .05) postintervention. The 2 exercise groups showed significant increase in Fmax compared with the control group (P < .05). Similarly, increase in GS was significantly higher in both the exercise groups compared with the control group (P < .05). No significant difference was observed in change in muscle function between the 2 exercise groups (P > .05). CONCLUSIONS: Structured physical activity along with protein supplementation resulted in improved muscle function in children. Yoga and PE showed a comparable impact on muscle force.

Increase of jump performance during GH treatment in short children born SGA.

Background: Short children born small for gestational age (SGA) often have low muscle mass. Studies on maximal isometric grip-force (MIGF) observed lower muscle strength in these children. In contrast to MIGF, jumping is an everyday muscle activity for children. Our hypothesis was that GH treatment would cause an increase in jumping strength. So, we aimed to study jumping by mechanography in short SGA children before and during GH treatment. Methods: Monocentric prospective longitudinal study in a tertiary pediatric endocrinology center. We studied 50 prepubertal short children (23 females) born SGA (mean age 7.2 y, height -3.24 SDS) during GH treatment (mean dose 45 µg/kg/d). Main outcome measures were Peak jump force (PJF) and peak jump power (PJP) measured by Leonardo® ground reaction force plate at baseline and after 12 months of GH treatment. Mechanography data were compared to sex, age and height related references (SD-Score). Fitness was estimated as PJP/kg body weight by use of the Esslinger-Fitness-Index (EFI). Results: At start of GH treatment PJP/body weight was low at -1.52 SDS and increased significantly to -0.95 SDS during 12 months of treatment (p<0.001). PJF was low-normal compared to height dependent references and remained unchanged. PJP was normal compared to height dependent references and increased only slightly from -0.34 to -0.19 SDSHT. Conclusions: Jumping performance (EFI) measured by mechanography increased during one year of GH treatment in short children born SGA.

Jumping Mechanography: Reference Centiles in Childhood and Introduction of the Nerve-Muscle Index to Quantify Motor Efficiency.

Jumping mechanography provides robust motor function indicators among children. The study aim was to develop centiles for the single 2-leg jump (S2LJ) in German children and adolescents and to identify differences in children with obesity. Data were collected in 2004-2021 through the German DOrtmund Nutritional and Anthropometric Longitudinally Designed (DONALD) study. All participants (6-18 years, mean age 11.4) performed annually an S2LJ aiming for maximum height on a Ground Reaction Force Platform. LMS (lambda-mu-sigma), including resampling, was used to develop centiles for velocity (vmax), jump height (hmax), relative force (Fmax/BW), relative power (Pmax/mass), impulse asymmetry and a new parameter to describe jump efficiency, the Nerve-Muscle Index (NMI), defined as vmax/(Fmax/BW). Data from 882 children and adolescents were analyzed (3062 measurements, median 3 per individual). In females, Fmax/BW values were higher in younger age but remained constant in adolescence. vmax, hmax and Pmax/mass increased in childhood, reaching a plateau in adolescence. In males, vmax, hmax and Pmax/mass showed a constant increase and the Fmax/BW remained lower. Children with obesity showed lower Fmax/BW, hmax, vmax and the NMI, hence, lower velocity per relative force unit and less efficient jump. The centiles should be used to monitor motor development in childhood. The NMI is a surrogate for motor efficiency.

Compartment-specific effects of muscle strength on bone microarchitecture in women at high risk of osteoporosis.

BACKGROUND: It is well known that skeletal integrity is influenced by the musculature. Poor muscle strength (i.e. sarcopenia) is considered a major predictor of fragility fractures. While this observation appears particularly relevant for older women with increased risk of osteoporosis, there has been no comprehensive investigation to determine the influence of muscle performance on compartment-specific bone microarchitecture in multiple body regions. METHODS: We retrospectively analysed data from different muscle performance and bone microarchitecture assessments in 230 women (aged 21 to 87 years) at high risk of osteoporosis. Muscle performance tests included grip strength and chair rising test (CRT) combined with mechanography. Balance was determined by Romberg posturography. Areal bone mineral density (BMD) was measured by dual-energy X-ray absorptiometry (DXA) at the hip and lumbar spine. Compartment-specific volumetric BMD, microarchitecture, and geometry were assessed by second-generation high-resolution peripheral quantitative computed tomography (HR-pQCT) at multiple skeletal sites (distal radius, tibia, and fibula). Regression models were applied to test for interactions between muscle and bone parameters. Subgroups were defined to compare women with osteoporosis and osteosarcopenia regarding BMD and microarchitecture. RESULTS: While osteoporosis was diagnosed in 115/230 (50.0%) women, sarcopenia was detected in 38/230 (16.5%). Positive associations of both grip strength and CRT maximum force with cortical geometric and microarchitectural parameters were detected at all measured sites, with the strongest effect applying to CRT maximum force and tibial parameters (e.g. tibial cortical area R2  = 0.36, P < 0.0001, and tibial cortical thickness R2  = 0.26, P < 0.0001). Balance parameters showed much weaker or no associations with HR-pQCT parameters. Major associations between muscle strength and trabecular parameters could not be confirmed. Age and body mass index were confirmed as negative and positive predictors for several microarchitectural parameters, respectively. An independent predictive value of grip strength on radial, tibial, and fibular (all P < 0.01) cortical area and of CRT maximum relative force on cortical thickness (all P < 0.05) was revealed. Women with osteosarcopenia showed significantly reduced cortical HR-pQCT parameters but no differences in DXA values compared with women with osteoporosis but no sarcopenia. Stratification by fracture and treatment status revealed that vertebral fractures and denosumab treatment altered the muscle-bone interaction. CONCLUSIONS: A systemic interaction between muscle strength and bone microarchitecture was demonstrated, and this interaction appears to be primarily with the cortical bone compartment. The value of muscle assessments in fracture risk evaluation may be partly mediated by their effects on bone microarchitecture.