Often after an acute injury of the knee the quadriceps muscle will not contract, which is called âquad inhibition.â. Inability to straighten the leg. Athletes with acute patellar injuries may find that they cannot flex the knee joint fully or straighten the leg. This may be exacerbated by swelling of the knee.
The alkali metals are a group (column) in the periodic table consisting of the chemical elements lithium (Li), sodium (Na), potassium (K), rubidium (Rb), caesium (Cs), and francium (Fr).
The alkali metals, halogens and noble gases are three important groups in the periodic table. The alkali metals are soft, reactive metals. They react vigorously with water and become more reactive as you go down the group.The halogens are reactive non-metals.They become darker as you go down the group.he alkali metals have the following properties in common: 1  they have low melting and boiling points compared to most other metals. 2  they are very soft and can be cut easily with a knife. 3  they have low densities (lithium, sodium and potassium will float on water).