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espanolDado que la suplementacion con creatina puede atenuar el dano inducido por el ejercicio e influir directamente en el sistema ATP-CP, predominante en el voleibol, el proposito del estudio es evaluar los efectos de la suplementacion con creatina (Cr) sobre los marcadores de dano muscular como creatina quinasa (CK) y lactato deshidrogenasa (LDH), dolor muscular de aparicion tardia (DOMS) y rendimiento fisico en atletas de voleibol. Se realizo un estudio controlado con modelo doble ciego, en el que catorce jugadores de voleibol (menores de 20 anos) se dividieron en 2 grupos: creatina y placebo donde suplementaban (0.3 g/kg) de creatina o placebo durante 7 dias (fase de carga) y 0.1 g/kg) durante los siguientes 4 dias (fase de mantenimiento). Antes y despues de cada fase de suplementacion, los jugadores se sometieron a pruebas de rendimiento fisico y recoleccion de muestras de sangre para evaluar CK, LDH y la concentracion de creatina en plasma. EnglishGiven that creatine supplementation may attenuate exercise-induced damage and directly influence the ATP-CP system, predominant in volleyball, the purpose of the study is to evaluate the effects of creatine (Cr) supplementation on muscle damage markers; creatine kinase (CK) and lactate dehydrogenase (LDH), delayed onset muscle soreness (DOMS) and physical performance in volleyball athletes.Fourteen volleyball players (under- 20 y) were divided into 2 groups: Creatine supplemented and Placebo. Double-blind controlled supplementation was performed using (0.3 g/kg) creatine or placebo for 7 days (loading phase) and (0.1 g/kg) for the next 4 days (maintenance phase). Before and after the supplementation phases, the players underwent Physical Performance Testing and blood sample collection to evaluate CK, LDH, and plasma creatine concentration.

Background: Graft tears and contralateral anterior cruciate ligament (ACL) tears are common in pediatric athletes after ACL reconstruction. Use of objective return-to-sports (RTS) criteria, in particular physical performance tests (PPTs), is believed to reduce the incidence of secondary injury; however, pediatric norms for these tests are unknown. Purpose: To establish a proof of concept for the creation of age- and sex-based norms for commonly used RTS PPTs in healthy pediatric athletes, allowing the creation of growth curves for clinical referencing. Study Design: Cross-sectional study; Level of evidence, 3. Methods: A total of 100 healthy people who were between the ages of 6 and 18 years and involved in organized sports were enrolled, with even distributions of age and sex. All participants underwent 9 common RTS PPTs: stork test, stork test on Bosu, single-leg squat, single-leg squat on Bosu, clockwise and counterclockwise quadrant hops, single-leg hop for distance, 6-m timed hop, and triple crossover hop for distance. Mean performance across limbs was calculated for each individual. Chronological age, height, weight, sex, and self-reported Pubertal Maturational Observational Scale (PMOS) score were recorded. Univariable and multivariable models were created for each PPT, assessing the importance of the recorded descriptive variables. Quantile regression was used to create growth curves for each PPT. Results: The cohort was 52% female, and the mean ± standard deviation age was 11.7 ± 3.6 years. PMOS was highly correlated with age ( r = 0.86) and was excluded from the regressions. In univariable regression, age, height, and weight were strong predictors of performance for all PPTs, whereas sex was a predictor of performance on the single-leg and triple crossover hops for distance (with males outperforming females). Height and weight were excluded from multivariable regression because of multicollinearity with age. Multivariable regression showed predictive patterns for age and sex that were identical to those shown in the univariable analysis. Given ceiling effects, quantile regression for the stork tests was not possible, but quantile regression growth curves were successfully created for the 7 remaining PPTs. Conclusion: Chronological age and sex accurately predicted performance on common RTS PPTs in pediatric patients. The growth curves presented herein could assist clinicians with benchmarking pediatric patients postoperatively against a healthy athletic cohort.

Exercise is critical for health maintenance in late life. The COVID-19 shelter in place and social distancing orders resulted in wide-scale interruptions of exercise therapies, placing older adults at risk for the consequences of decreased mobilization. The purpose of this paper is to describe rapid transition of the Gerofit facility-based group exercise program to telehealth delivery. This Gerofit-to-Home (GTH) program continued with group-based synchronous exercise classes that ranged from 1 to 24 Veterans per class and 1 to 9 classes offered per week in the different locations. Three hundred and eight of 1149 (27%) Veterans active in the Gerofit facility-based programs made the transition to the telehealth delivered classes. Participants’ physical performance testing continued remotely as scheduled with comparisons between most recent facility-based and remote testing suggesting that participants retained physical function. Detailed protocols for remote physical performance testing and sample exercise routines are described. Translation to remote delivery of exercise programs for older adults could mitigate negative health effects.

Purpose/Hypothesis: Return to sport (RTS) after anterior cruciate ligament (ACL) reconstruction in children is associated with a much higher risk (˜30%) of subsequent ACL injury than in adults. In adults, delaying RTS until objective physical performance test (PPT) criteria are met reduces re-injury rates. However, normative data on PPTs in children is missing, limiting their utility in this high-risk population. Designing age-specific pediatric guidelines for RTS is therefore a critical area of investigation. Number of Subjects: 63 Materials/Methods: We designed a prospective observational study of 130 healthy pediatric athletes (ages 6 - 18 years, 5 males and 5 females of each age). Each athlete underwent a series of 10 functional tests assessing balance (Y-Balance Test, stork test, stork test on Bosu ball), strength (single leg squat, single leg hop) and composite neuromuscular control (single leg squat on Bosu ball, clockwise and counterclockwise quadrant hop, 6 m timed hop and triple crossover hop). Demographic data including sex, chronologic age, Pubertal Maturity Observational Score (PMOS), height, weight, and body mass index (BMI). Testing order was randomized to reduce confounding from fatigue. Our primary hypothesis was that PPT results would vary predictably with chronologic age. For each PPT, multivariable linear regression was performed including age, sex, PMOS, BMI and testing order as independent variables. Standard “growth curves” for each test were then built based on age and sex. Results: Sixty-three athletes (29 male, 34 female) have completed testing so far (48% enrollment). Mean age was 10.7 +/- 3.2 years (range 6 - 18). Mean PMOS was 3.2 +/- 3.1 (range 0 - 9). PMOS was strongly correlated with chronologic age (Pearson’s? = 0.83), therefore PMOS was excluded as a predictor variable in regression models to avoid multicollinearity. Chronologic age was an independent predictor of all PPT results (p < 0.05 in all cases). There was a learning effect for the Bosu Stork test, with athletes doing this test later in the sequence performing better (ß = 2.47, 95% CI 0.74 - 4.19, p = 0.006). Female sex was an independent predictor of a shorter triple crossover hop distance (ß = -74.1, 95% CI -106.9 to -41.2, p < 0.0001). Balance tests showed the least linear relationships with age. The stork test had a clear ceiling effect by age 10 in females and 13 in males. The Bosu Stork test showed wide variability at all ages. Conclusion: Chronologic age is a strong, typically linear predictor of commonly used PPTs in children. The PMOS did not add additional predictive value. Clinical Relevance: The normative data generated in this study help understand normal neuromuscular development, and provide a foundation for creating age-specific RTS scores.

Digital breast tomosynthesis has become accepted in clinical use. It is important to physically evaluate a system to ensure that it is working at full performance. Non-linear reconstruction processing is proposed to improve interpretation of clinical images by enhancing the minute contrasts of breast tissue while suppressing metal artifacts. Because existing measuring methods assume a linear system, physical evaluation applied to images reconstructed with non-linear processing may result in unnatural values. We investigated the influence of different reconstruction methods on physical evaluations. We suggest using images reconstructed by back projection processing without a filter to ensure the device performance directly.

There is a paucity of evidence-based care protocols for the management of patellofemoral (PF) joint conditions. There remains ambiguity in defining conditions; PF pain, malalignment, instability are intersecting patient cohorts in clinical practice. Treatment should address muscle strength deficits as well as movement pattern dysfunctions frequently observed in association with PF conditions. Quadriceps muscle dysfunction has significant heterogeneity in its etiology. The hip contributes to PF pathology as a consequence of femoral internal rotation and adduction. Inadequate gluteus medius ans maximus muscle performance is associated with kinematic flaws. Various surgical procedures are employed to address PF instability and associated pain patterns. Postoperative progressions should respect specific demands for bony healing, soft tissue healing and/or ligamentous graft incorporation. Symptomatic cartilage lesions may limit return to full function. Physical performance testing activities can be useful to measure patient progress and advise on return to activity/play.

Previous studies have shown that low serum 25-hydroxyvitamin D [25(OH)D] level is a risk factor for falls among the elderly in European and North American populations. We used a cross-sectional community-based survey to study the association of serum 25(OH)D level and falls among Japanese community-dwelling elderly. A total of 2957 elderly persons (950 men and 2007 women) 65-92 yr of age who participated in mass health examinations for the prevention of geriatric syndrome for the elderly underwent an interview, blood analysis, and physical performance testing. Experience of falls over the previous year was assessed in an interview. Physical performance tests of handgrip strength, stork standing time with the eyes open, and normal waking speed as risk factors for falls among the elderly were conducted. Serum albumin and 25(OH)D concentrations were analyzed. Mean 25(OH)D concentration was significantly lower in women than in men (p < 0.001). Women showed a significant decline of 25(OH)D level with increased age (p < 0.001). There was also a significant difference in the prevalence of 25(OH)D insufficiency [25(OH)D level < 20 ng/ml] between the sexes (p < 0.001). The rate of falls was significantly higher in the lowest quartile of 25(OH)D level in women (p = 0.02) and in women with 25(OH)D insufficiency (p = 0.001). Women also showed significant declines in all three fall-related physical performance tests. Multiple logistic regression analysis showed significant and independent associations between 25(OH)D level and experience of falls in women only (p = 0.01). Low 25(OH)D level was significantly associated with a high prevalence of falls in Japanese elderly women because of their inferior physical performance. Low serum 25(OH)D levels appear preventable and easily treated; there is an evident need for greater awareness to screen and thus prevent this condition.

This paper introduces usage of ADAMS in modeling and simulation of tracked vehicle performance. And how to make full use of the ADAMS Toolkit (ATV) in modeling and simulation is analyzed, further applications of the ATV software in simulating dynamic performance of a tracked vehicle are made. The following three typical examples are simulated: (1) making the vehicle climb a ramp with slope of 32 degrees, (2) making the vehicle get over a 2.8m ditch, (3) making the vehicle cross a 0.8m high obstacle wall. Through analysis of simulation results of the prototype and later physical performance testing, the conclusion can be made that the simulation results are consistent well with the physical testing data. In the process of simulation, a DLL file is built. And the problem of “sliding down” the ramp with slope of 32-degree while it is climbing up is encountered, through making various efforts, this “sliding down” problem is finally solved successfully....

To develop and field-test a physical performance measure (MPS-PPM) for individuals with Mucopolysaccharidosis I (MPS I), a rare genetic disorder.Motor performance and endurance items were developed based on literature review, clinician feedback, feasibility, and equipment and training needs. A standardized testing protocol and scoring rules were created. The MPS-PPM includes: Arm Function (7 items), Leg Function (5 items), and Endurance (2 items). Pilot data were collected for 10 subjects (ages 5-29 years). We calculated Spearman's rho correlations between age, severity and summary z-scores on the MPS-PPM.Subjects had variable presentations, as correlations among the three sub-test scores were not significant. Increasing age was related to greater severity in physical performance (r = 0.72, p0.05) and lower scores on the Leg Function (r = -0.67, p0.05) and Endurance (r = -0.65, p0.05) sub-tests. The MPS-PPM was sensitive to detecting physical performance deficits, as six subjects could not complete the full battery of Arm Function items and eight subjects were unable to complete all Leg Function items. Subjects walked more slowly and expended more energy than typically developing peers.Individuals with MPS I have difficulty with arm and leg function and reduced endurance. The MPS-PPM is a clinically feasible measure that detects limitations in physical performance and may have potential to quantify changes in function following intervention.

Through its association with fat-free mass (FFM), bioelectrical impedance analysis (BIA) offers an alternative to physical performance testing. We examined the relations between stature2/resistance (S2/R), FFM, and muscular strength in data from three studies of young military men and women. Resistance was measured at 50 kHz by using the conventional tetrapolar electrode method. FFM was based on skinfold thicknesses, and estimated with the regression equations of Durnin and Womersley. Strength was measured as a one-repetition maximum on an incremental lift test (IL1RM), which is widely used by the military services to predict overall body strength. Although there was an association between IL1RM and S2/R in each of these studies (correlations ranged from 0.35 to 0.53), correlations were strongest between FFM and S2/R (R = 0.53 to 0.85), indicating that BIA and FFM derived from skinfold thicknesses are better correlated with each other than are the relations of either of these with physical performance. Modest increases in FFM and strength in one 8-wk training study correlated with S2/R; however, large decreases in FFM and strength in another study (with weight losses of 10 kg in 8 wk) were not reflected by changes in S2/R. Thus, BIA is not particularly useful for performance prediction despite its moderate relation to FFM. BIA is especially problematic with large changes in body composition, for which there are apparent deviations in hydration status; expedient methods such as skinfold predictions will be more resistant to such effects.

The relationship between excessive idiopathic femoral anteversion and physical performance in adolescent and adult subjects is explored in 9 adults with excessive anteversion and in 10 age-matched controls subjected to extensive physical performance testing. Two hundred and forty-nine high school students were studied by assessing running speed and measuring hip rotation. Those with greatest internal rotation were isolated and compared with the total group. In both studies no relationship could be found between excessive anterversion and physical performance.