Comparison of body segment models for female high jumpers utilising DXA images.

In motion analysis of sport competitions, the question is often about the most convenient choice for defining the segment endpoints when no visible landmarks can be used. The purpose of the present study was to determine the location of the body centre of mass (CoM) of female high jumpers by using a high accuracy reaction board and two different segment models: Dempster (1955) and de Leva (1996). Digitising the bony landmarks from the images of dual energy x-ray absorptiometry (DXA) and overhead digital camera were used to compare the digitising accuracy.

Body composition and power performance improved after weight reduction in male athletes without hampering hormonal balance.

The aim of this study was to investigate the effects of a 4-week weight reduction period with high protein and reduced carbohydrate intake on body composition, explosive power, speed, serum hormones, and acid-base balance in male track and field jumpers and sprinters. Eight participants were assigned to a high weight reduction group (HWR; energy restriction 750 kcal·d) and 7 to a low weight reduction group (LWR; energy restriction 300 kcal·d). Energy and carbohydrate intake decreased significantly (p ≤ 0.

Determining the location of the body׳s center of mass for different groups of physically active people.

The purpose of the present study was to compare the location of the body center of mass (CoM) determined by using a high accuracy reaction board (RB) and two different segment parameter models for motion analysis (Dempster, 1955, DEM and de Leva, 1996 adjusted from Zatsiorsky and Seluyanov, ZAT). The body CoM (expressed as percentage of the total body height) was determined from several subjects including athletes as well as physically active students and sedentary people. Some significant differences were found in the location of the body CoM between the used segment models and the reaction board method for all male subjects (n=58, 57.

Comparison of impact characteristics of four different ice hockey arena dasher boards.

During recent years the incidence of ice hockey related concussions has increased. Therefore, the main aim of this study was to determine how dasher board materials and structures affect impact characteristics and thereby concussion risk. The measurements were divided into two parts; 1.

Bone density, structure and strength, and their determinants in aging sprint athletes.

Purpose: This study was undertaken to examine bone properties in masters sprinters of different ages and younger reference subjects. In addition, the association of sport-specific ground reaction force, muscle, training, and hormone characteristics with the bone parameters was evaluated in the athletes.

Methods: Bone densitometric, structural, and strength parameters were assessed by peripheral quantitative computed tomography at the distal and midtibia in 83 male sprinters (40-85 yr) and 19 physically active referents (31-45 yr).

Comparison of running kinematics between elite and national-standard 1500-m runners.

The aim of this study was to determine whether elite 1500-m runners differ in their running kinematics from national-standard 1500-m runners. Six national-standard male runners (seasonal best: 3 min 49.2 s +/- 3.

Loading and gait symmetry during level and stair walking in asymptomatic subjects with knee osteoarthritis: importance of quadriceps femoris in reducing impact force during heel strike?

Repetitive impulsive forces during walking are claimed to result in joint osteoarthritis (OA). The aim of this study was to investigate impact loading and gait symmetry during level and stair walking in asymptomatic elderly subjects with knee OA. It was hypothesised that pre-activity of the quadriceps femoris muscle (QF) would be an important factor reducing impulsive loading when walking on level ground.

Characteristics of the early flight phase in the Olympic ski jumping competition.

Early flight phase (approximately 40 m) of the athletes participating in the final round of the individual large hill ski jumping competition in Salt Lake City Olympics was filmed with two high-speed pan & tilt video cameras. The results showed that jumpers' steady flight position was almost completed within 0.5s.