The most abundant mineral element in the skeletal muscle is Potassium.

Potassium plays a crucial role in muscle function and is essential for maintaining proper muscle contraction, nerve function, and overall muscle health. It is an electrolyte that helps regulate the balance of fluids in the body and is involved in the transmission of nerve impulses and the contraction of muscles.

Explanation:
1. Potassium and muscle contraction:
- Potassium is required for the generation of action potentials in muscle cells. Action potentials are electrical impulses that stimulate muscle contraction.
- During muscle contraction, potassium ions move out of the muscle cells, which allows muscle relaxation. The movement of potassium ions across the cell membrane plays a key role in regulating the contraction and relaxation of muscles.
- Potassium helps maintain the resting membrane potential of muscle cells, which is necessary for proper muscle function.

2. Role of other mineral elements in muscle function:
a) Sodium: Sodium is also an essential mineral involved in muscle contraction. It works in conjunction with potassium to regulate the movement of electrical impulses in muscle cells. However, sodium is not the most abundant mineral element in skeletal muscle.
b) Calcium: Calcium is another important mineral involved in muscle contraction. It initiates the release of stored calcium from the sarcoplasmic reticulum, which leads to muscle contraction. However, calcium is not the most abundant mineral element in skeletal muscle.
d) Phosphorus: Phosphorus is an important mineral for overall muscle health, but it is not the most abundant mineral element in skeletal muscle.

In conclusion, potassium is the most abundant mineral element in the skeletal muscle. It plays a crucial role in muscle contraction, nerve function, and maintaining the balance of fluids in the body.