Strengthen your bones
What makes bones stronger and more durable? Although bone strength is genetically determined, there are certainly strategies that can improve it, particularly when it comes to physical activity and nutrition.
Paul Hough, an expert in exercise physiology, explains: “Weight-bearing activities, such as running, encourage a process called bone remodelling, which increases bone mineral density (BMD) and reduces the risk of fractures. However, not all forms of physical activity improve BMD. For example, cycling – a non-weight-bearing sport – is ineffective in increasing BMD. Indeed, BMD has been reported to be lower in cyclists compared to individuals who engage in weight-bearing activities.”
Paul suggests that adding strength training to your running programme is key to increasing your BMD. “Although typically associated with boosting muscle strength, resistance training is an excellent method of improving BMD,” he adds. “That’s why I recommend strength training for endurance athletes.”
Nutrition should be an equally high priority for anyone serious about looking after their bone
health, adds Paul. “What we eat strongly influences bone strength, in particular energy (calorie) intake in relation to energy expenditure. Energy availability (EA) is the amount of energy that is available to the body to fuel normal physiological functions after subtracting the energy expended through exercise. In essence, this is how much energy is left for the body after physical activity. EA can be reduced due to a low-calorie intake, increased energy expenditure, or a combination of both. A chronic low EA (inadequate energy intake) can reduce reproductive hormones and growth factors, which can lower BMD and increase the risk of fractures.” And what is in your diet is just as important as how many calories you consume.
“The composition of a diet greatly influences bone strength,” Paul explains. “The diet should include food and drink rich in calcium, as bone mineral content is largely formed from calcium and phosphorus. Other vitamins and minerals are also required for normal bone metabolism; for example, vitamin D and K, magnesium, zinc and fluoride. Therefore, it is essential to consume foods high in protein and a variety of vegetables, fruits, seeds and nuts.”
Sunshine should also play a key role in maintaining healthy bones, says Paul: “The body produces vitamin D when the skin is exposed to sun. So spend plenty of time out in the sunshine.”
How running affects bones
The continual forces on the body’s skeleton caused by running significantly increases bone mass, as Paul explains: “Running can improve BMD due to the repetitive forces applied to the bones during running. However, these forces are low compared to other sports such as football and tennis. Moreover, the load applied to the bones during running primarily occurs in a single plane at a constant rate (around 80 to 110 strides per minute in most runners). Studies in mice have demonstrated that high-impact loads applied in different directions are more effective at increasing BMD. This may be why team sport athletes and tennis players have a higher BMD than endurance athletes.” Paul emphasises the importance of a wellbalanced diet when running regularly. He explains: “In some individuals, running can actually have the opposite effect and reduce BMD. For example, people at risk of chronically low EA, such as young females and ultra-endurance athletes. Therefore, it is essential for these individuals to focus on consuming enough calories, vitamins and minerals within their diets. It is also sensible to increase mileage gradually and perform resistance training exercises.” Bone mineral density and strength peak in the late 20s, but muscle and bone mass begin to decline after our mid-30s, as Paul explains: “In the decade following
‘Low energy intake can reduce reproductive hormones and growth factors, and increase the risk of fractures.’
our mid-20s, the reduction of muscle and bone mass leads to a decrease in strength of both tissues. A substantial loss of bone can lead to osteoporosis, a skeletal disease characterised by low bone mass and structural weakening of the bone; this reduces bone strength and increases susceptibility to fracture. Consequently, the risk of stress fractures increases amongst older runners, particularly if energy intake is inadequate and weekly mileage is rapidly increased. Diet, resistance training and sensible programme design become increasingly important to senior runners.”
Vitamin-packed nuts and seeds can bolster bone health