The importance of calcium for the female athlete
Although consuming enough calcium is an important element of a healthy diet for the general population, it is even more so for athletes, especially females. Calcium is commonly known for aiding the prevention of low Bone Mineral Density (BMD) which is a predisposing factor for stress fractures, osteopenia and osteoporosis, but calcium is also a vital mineral for muscle contractions.
Athletes are more vulnerable to being deficient in calcium due to higher levels of perspiration through high intensity exercise. Those who have inadequate calcium levels may suffer from weaker, faster fatiguing muscle contractions and faster breakdown of bone cells. Thus, increasing risk of injury as well as diminishing performance and longevity of an athlete’s career.
For Bone Health
Our bones not only give the body a functional structure, mobility, support and protection but also offer a “storehouse” for essential minerals; calcium and phosphorus. 99% of the body’s total calcium is stored in our bones, serving as a reservoir for maintaining levels of calcium in our cells and blood which is vital for the body’s organs, muscles and nerves to function.
Cells within our bones called osteoclasts are always breaking down bone content through it’s acidic environment underneath the cell, which dissolves the matrix of bone to excrete calcium and phosphorus, allowing these minerals to be available for reabsorption. At the same time, there are cells called osteoblasts which help rebuild bone mass via laying down osteoids; an organic material which then forms new bone material, countering the effects from osteoclasts. This breakdown and repair cycle is known as the “remodelling cycle”.
Within the remodelling cycle the importance of sufficient calcium intake is twofold. Firstly, an unsubstantial calcium intake can lead to a greater level of bone material break down offsetting the status quo of bone formation. Secondly, osteoblasts need calcium to fascinate their bone building properties which if in a limited supply leads to inadequate remodelling, resulting in reduced bone material density.
Through the aging process our remodelling cycle becomes more disadvantaged as the rate of osteoblast repair and regrowth doesn’t match of the rate of breakdown from osteoclasts. This is most heard of with woman post-menopause suffering from conditions such as osteopenia and osteoporosis yet many people live with these conditions not knowing they have them until they suffer from a fracture or break.
Although, osteopenia and osteoporosis tend to be seen as a more mature persons’ condition, inadequate calcium intake can prematurely begin the long-term degeneration process of bone density even from a young age. Consuming enough calcium is vital during developing years in order to facilitate correct bone formation and to supply the body during periods of rapid growth; growth spurts. Suboptimal calcium intake during this time accelerates the degeneration due to a reduced density starting point.
Weight bearing exercises is a great way to promote increased bone density especially when performed over a long-term period. Yet, regularly partaking in exercise requires elevated consumption of calcium, otherwise repetitive loading without optimal recovery via the remodelling cycle can lead to further breakdown, increasing the risk in those trying to prevent such issues. Similar to osteoporosis thin fragile bones tend to only be found after the individual suffers from a break resulting from a fall or collision.
For Muscle Contractions
The remaining 1% of our body’s calcium storehouse is within our muscle cells. Calcium is used for both muscular contraction and muscular relaxation. Muscle contractions follow the sliding filament theory where actin and myosin filaments within myofilaments bind and slide past each other. Many microscopic myofilaments group together to form a single muscle fibre. When many muscle fibres contract, it can visibly be seen through the appearance of muscles being shorter and thicker.
For the process of muscle contraction to begin, sarcoplasmic reticulum; a tube-like network surrounding each myofilament, releases calcium into the myofilaments via electrical input from the brain when movement is desired. An elevated calcium concentration within the myofilaments begin a chain reaction, where the actin and myosin cross bridges slidealong each other shortening a muscle fibre’s length.
Once the electrical input from the brain stops the calcium in the myofilaments returns to the sarcoplasmic reticulum, in order for the muscle to relax. The process of calcium transferring to and from sarcoplasmic reticulum and myofilaments is called the calcium cycle.
Low blood calcium levels lower calcium contractions within the sarcoplasmic reticulum and can cause muscle irritability such as cramps and involuntary muscle twitching. Muscles struggling to relax due to inadequate calcium intake will have an impaired recovery due to muscle contraction limits blood flow to the area. It also effects the level of force production of a muscle due to decreased calcium concentration in the myofilaments hindering muscle fibre contraction. Less myofilaments contracting leads to weaker muscle contractions and limited force production.
Adequate Daily Calcium Intake
Now you’re aware of the vital role calcium has it’s time to know how much you should be consuming in your diet. Below is a table of adequate daily calcium intake got various ages.
Final Words
Remember that as an athlete your dietary needs will be greater than the general population with the above values not tailored for athletes. In order for you to get the most optimal absorption of calcium supplementation of Vitamin D can drastically help especially those in countries with high vitamin D deficiencies such as the UK.
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