Answer:
Explanation:
Forehand groundstroke effectiveness is important for tennis success. Ball topspin angular velocity (TAV) and accuracy are important for fore hand groundstroke effectiveness, and have been extensively studied, previously; despite previous, quality studies, it was unclear whether certain racquet kinematics relate to ball TAV and shot accuracy during the forehand groundstroke. This study evaluated potential relationships between (1) ball TAV and (2) forehand accuracy, and five measures of racquet kinematics: racquet head impact angle (i.e., closed or open face), horizontal and vertical racquet head velocity before impact, racquet head trajectory (resultant velocity direction, relative to horizontal) before impact, and hitting zone length (quasi-linear displacement, immediately before and after impact). Thirteen collegiate-level tennis players hit forehand groundstrokes in a biomechanics laboratory, where racquet kinematics and ball TAV were measured, and on a tennis court, to assess accuracy. Correlational statistics were used to evaluate potential relationships between racquet kinematics, and ball TAV (mixed model) and forehand accuracy (between-subjects model; α = 0.05). We observed an average (1) racquet head impact angle, (2) racquet head trajectory before impact, relative to horizontal, (3) racquet head horizontal velocity before impact, (4) racquet head vertical velocity before impact, and (5) hitting zone length of 80.4 ± 3.6˚, 18.6 ± 4.3˚, 15.4 ± 1.4 m·s-1, 6.6 ± 2.2 m·s-1, and 79.8 ± 8.6 mm, respectively; and an average ball TAV of 969 ± 375 revolutions per minute. Only racquet head impact angle and racquet head vertical velocity, before impact, significantly correlated with ball TAV (p < 0.01). None of the observed racquet kinematics significantly correlated to the measures of forehand accuracy. These results confirmed mechanical logic and indicate that increased ball TAV is associated with a more closed racquet head impact angle (ranging from 70 to 85˚, relative to the ground) and increased racquet head vertical velocity before impact.
Answer:
Tissue is a group of cells or fluid that work together to perform a specific job in the body like cells in an organ like the kidney or heart or blood cells that carry oxygen to and waste materials from the cells in the body. This is why itd be very important
Explanation:
Vaccination of non-immune individuals is considered the key strategy in limiting the spread of measles during outbreaks.
Explanation:
- Measles is an extremely contagious, severe disease caused by a virus in the paramyxovirus group and it is usually spread by direct contact and the air.
- The virus affects the respiratory tract, then circulates throughout the body. Measles is a human disease and is not recognized to occur in animals.
- Unvaccinated young children are at the biggest peril of measles and its complexities, including death.
- Unvaccinated pregnant women are also in danger.
- An Unvaccinated person (non-immune individual not vaccinated or was treated but didn't increase immunity) can be infected.
- Routine measles vaccination for non-immune children and adult individuals united with mass immunization operations in countries with high occurrence and death rates are key public health strategies to overcome global measles deaths.
- The measles vaccine has been in treatment for nearly 60 years. It is secure, efficient and economical.
- It costs around one US dollar to immunize a child against measles.
Answer:
The fat soluble vitamins A, D, E and K are absorbed from the intestinal lumen using the same mechanisms used for absorption of other lipids. In short, they are incorporated into mixed micelles with other lipids and bile acids in the lumen of the small intestine and enter the enterocyte largely by diffusion.
Explanation:
Pure determination and hardwork
