Age-related change in sit-to-stand power in Japanese women aged 50 years or older

BACKGROUND: This study examined whether the age-related change in power, calculated from the score of a sit-to-stand (STS) test, corresponds to those in knee extension torque and leg lean tissue mass in Japanese women aged 50 years or older. FINDINGS: Time for a 10-times-repeated STS test and knee extension torque were determined in 556 Japanese women aged 50 to 94 years. STS power was calculated using an equation reported previously. In addition, leg lean tissue mass was estimated using muscle thicknesses determined at thigh and lower leg. STS power, knee extension torque, and lean tissue mass were negatively correlated to age. STS power and knee extension torque, expressed as the percentages of the mean value of the corresponding variable for the subjects aged 50 to 54 years were lower than that of lean tissue mass in the subjects aged 60 years or over, and were similar in those aged under 75 years. However, the relative value of STS power was lower than that of knee extension torque in the subjects aged over 75 years. CONCLUSIONS: In Japanese women aged 50 to 74 years, STS power can be a convenient measure for assessing the age-related decline in knee extension torque, but not for leg lean tissue mass. At over 75 years old, the magnitude of the age-related decline in STS power does not parallel to that in the force generation capability of knee extensor muscles

Prevention of downhill walking-induced muscle damage by non-damaging downhill walking

Purpose: Mountain trekking involves level, uphill, and downhill walking (DW). Prolonged DW induces damage to leg muscles, reducing force generating ability and muscle coordination. These increase risks for more serious injuries and accidents in mountain trekking, thus a strategy to minimize muscle damage is warranted. It has been shown that low-intensity eccentric contractions confer protective effect on muscle damage induced by high-intensity eccentric contractions. This study tested the hypothesis that 5-min non-damaging DW would attenuate muscle damage induced by 40-min DW, but 5-min level walking (LW) would not. Methods: Untrained young men were allocated (n = 12/group) to either a control or one of the two preconditioning groups (PRE-DW or PRE-LW). The PRE-DW and PRE-LW groups performed 5-min DW (-28%) and 5-min LW, respectively, at 5 km/h with a load of 10% body mass, 1 week before 40-min DW (-28%, 5 km/h, 10% load). The control group performed 40-min DW only. Maximal knee extension strength, plasma creatine kinase (CK) activity, and muscle soreness (0±100 mm visual analogue scale) were measured before and 24 h after 5-min DW and 5-min LW, and before and 24, 48, and 72 h after 40-min DW. Results: No significant changes in any variables were evident after 5-min DWand 5-min LW. After 40- min DW, the control and PRE-LW groups showed significant (PP Conclusions: The results supported the hypothesis and suggest that performing small volume of downhill walking is crucial in preparation for trekking

CONTRIBUTION OF FORWARD AND VERTICAL IMPULSES DURING MAXIMAL 5OM SPRINTING TO THE MAXIMUM RUNNING VELOCITY IN SPRINTERS

The present study developed a 50 m-forceplate system and examined relationships between the impulse calculated from ground reaction force (GRF) from start to 50m and the maximum running velocity (Vfmax). Thirty five male sprinters performed maximal sprint on the system, using starting block. The forward and vertical components of impulses (IMPf and IMPv. respectively) were computed far each support phase by integrating the GRF. The highest correlation coefficients for both IMPf(~0.736)a nd IMPv(r=-0.729) were found at the distance of 10 m from the start. These results indlcate the ability to keep lMPv low and lMPf high seems to be important for achieving greater Vfmax, notably in the initial stage of acceleration phase

Effect of maturation on muscle quality of the lower limb muscles in adolescent boys

BACKGROUND: The purpose of this study was to clarify the effect of maturation on the muscle quality of the lower limb muscles around puberty. METHODS: Subjects were 117 Japanese boys age 12 to 15 years. The maturity status was assessed by using a self-assessment of stage of pubic hair development based on the criteria of Tanner. On the basis of the criteria, subjects were divided into the prepubescent or pubescent group. Muscle thickness of knee extensors and plantar flexors were measured by a B-mode ultrasound. Muscle volume index (MV) was calculated from muscle thickness and limb length. Maximal voluntary isometric joint toques (TQ) of knee extension and ankle plantar flexion were measured using a myometer. Muscle quality was derived from dividing TQ by MV (TQ/MV). RESULTS: In both muscles, TQ-MV relationships were also similar between the prepubescent and pubescent groups, and there was no significant difference in TQ/MV between the two groups when chronological age was statistically adjusted. CONCLUSION: The current results indicate that, for adolescent boys, the muscle quality of the lower limb muscles is not significantly influenced by maturation

ACCURACY IN DETERMINING KINETIC PARAMETERS WITH FORCE PLATES EMBEDDED UNDER SOIL-FILLED BASEBALL MOUND

We developed a force measurement system embedded in a soil-filled mound for measuring ground reaction forces (GRF) acting on baseball pitchers and examined the accuracy of determining the point of force application (PFA) and kinetic parameters computed from GRF. Three 1.0 x 0.9 m2 force platforms were placed on the concrete foundation of an indoor sports facility and three bays were fixed onto the aluminum plates of the force plateorms. In each tray, clay-blocks were laid tightly and a mixture of red sand and volcanic-ash was used to make a smooth surface layer. The mean absolute error was 6.0 f 4.0 mm in determining PFA, less than 15.5 Ns (5% of the true value) in determining linear impulse. These results suggest that the present method is valid for measuring the PFA and GRF acting on the pitcher's legs for analyzing kinetics of pitching performances

Mechanical interaction between neighboring muscles in human upper limb: evidence for epimuscular myofascial force transmission in humans

To confirm the existence of epimuscular myofascial force transmission in humans, this study examined if manipulating joint angle to stretch the muscle can alter the shear modulus of a resting adjacent muscle, and whether there are regional differences in this response. The biceps brachii (BB: manipulated muscle) and the brachialis (BRA: resting adjacent muscle) were deemed suitable for this study because they are neighboring, yet have independent tendons that insert onto different bones. In order to manipulate the muscle length of BB only, the forearm was passively set at supination, neutral, and pronation positions. For thirteen healthy young adult men, the shear modulus of BB and BRA was measured with shear-wave elastography at proximal and distal muscle regions for each forearm position and with the elbow joint angle at either 100° or 160°. At both muscle regions and both elbow positions, BB shear modulus increased as the forearm was rotated from a supinated to pronated position. Conversely, BRA shear modulus decreased as function of forearm position. The effect of forearm position on shear modulus was most pronounced in the distal muscle region when the elbow was at 160°. The observed alteration of shear modulus of the resting adjacent muscle indicates that epimuscular myofascial force transmission is present in the human upper limb. Consistent with this assertion, we found that the effect of muscle length on shear modulus in both muscles was region-dependent. Our results also suggest that epimuscular myofascial force transmission may be facilitated at stretched muscle lengths

Preparation and Organization of Golf Tournament

Import 05/08/2014Cílem této bakalářské práce je popsat a objasnit všechny náležitosti přípravy a organizace golfového turnaje. Zaměřil jsem se na pořádání regionálního amatérského golfového turnaje. Zvolenou situaci jsem řešil za pomocí fiktivního příkladu golfového turnaje. V této práci jsem použil výzkumné metody SWOT analýza, SMART analýza, introspekce a výzkumné techniky rozhovor a pozorování. Díky zvolenému příkladu přípravy a organizování golfového turnaje bylo možné, aplikovat obecné zákonitosti a dílčí procesy a hodnoty do reálné situace, která přibližuje všechny detaily pořádání sportovně společenské akce a zároveň reflektuje postavení golfu v České republice. Tato práce by měla sloužit jako návod a zdroj informací pro potenciální organizátory golfových turnajů.The goal of this bachelor thesis is to describe and clarify all the essentials of preparation and organization of a golf tournament. I aimed at running a regional amateur golf tournament. I solved the situation by creating fictive example of a golf tournament. In this thesis I used the exploratory methods SWOT analysis, SMART analysis and introspection and exploratory techniques dialogue and observation. Thanks to the example of preparation and organization of the golf tournament I was able to apply general regularities and particular processes and values to the real situation, which introduces all the details of running a sports-social event and also reflects the condition of golf in the Czech Republic. This bachelor thesis should be instrumental towards the potential organizers of the golf tournament as a guideline and source of information.115 - Katedra managementuvelmi dobř

QTL/microarray approach using pathway information

<p>Abstract</p> <p>Background</p> <p>A combined quantitative trait loci (QTL) and microarray-based approach is commonly used to find differentially expressed genes which are then identified based on the known function of a gene in the biological process governing the trait of interest. However, a low cutoff value in individual gene analyses may result in many genes with moderate but meaningful changes in expression being missed.</p> <p>Results</p> <p>We modified a gene set analysis to identify intersection sets with significantly affected expression for which the changes in the individual gene sets are less significant. The gene expression profiles in liver tissues of four strains of mice from publicly available microarray sources were analyzed to detect trait-associated pathways using information on the QTL regions of blood concentrations of high density lipoproteins (HDL) cholesterol and insulin-like growth factor 1 (IGF-1). Several metabolic pathways related to HDL levels, including lipid metabolism, ABC transporters and cytochrome P450 pathways were detected for HDL QTL regions. Most of the pathways identified for the IGF-1 phenotype were signal transduction pathways associated with biological processes for IGF-1's regulation.</p> <p>Conclusion</p> <p>We have developed a method of identifying pathways associated with a quantitative trait using information on QTL. Our approach provides insights into genotype-phenotype relations at the level of biological pathways which may help to elucidate the genetic architecture underlying variation in phenotypic traits.</p