It’s common sense that increased exercise in youth and old age has its advantages. There is much evidence to suggest that increased physical activity enhances cardio-vascular health, tackles obesity and aids the treatment and prevention of type 2 diabetes, but, according to two internationally renowned experts, exercise – and specifically weight-bearing exercise – at the extremes of ageing are vital for bone and joint health too.
Speaking at the 10th annual Scientific Meeting of the Faculty of Sports and Exercise Medicine at the Royal College of Surgeons in Ireland last week, Prof Bengt Saltin from the University of Copenhagen and Dr Nicola Crabtree from Birmingham Children's Hospital spoke of the importance of weight-bearing exercise in both youth and old age to improve bone development and joint mobility.
Saltin is considered one of the world’s foremost sports physiologists; he says in a person’s latter years, weight-bearing exercise or strength training can have a significant impact on mobility and injury prevention.
He says strength-training exercise results in greater muscle strength, leading to improved joint mobility and stability.
Saltin says we should spend our whole lives gearing up to having as pain-free an old age as possible by leading an active lifestyle, but that it is possible to begin strength training as an older person and to achieve a greater level of mobility, stability and joint strength through exercise.
He believes it is something that is becoming more understood in Denmark and elsewhere in Scandinavia, where an ageing population means gyms and other fitness facilities increasingly have to consider the needs of older people.
Saltin says that mobility is a vital issue for the elderly person and he recommends people exercise both the upper and lower body in order to maintain flexibility.
While weight-bearing exercise in youth impacts on bone density, in older age exercise can result in greater muscle strength and stability at joint sites, resulting in less tension around the joints. This, in turn, results in fewer falls but also in improved recovery when falls do occur, as well as a greater sense of emotional wellbeing as the person does not live in fear of falling, either in the home or outside.
He states that in old age it is necessary to use equipment in the gym or therapeutic setting that results in close to maximal contraction of the muscle at joint sites. It is, he says, tough and takes a number of weeks to be able to work up to the necessary level of muscle exertion, but the results can be striking. He recommends a series of exercises, as advised, that work on the knees, hips, shoulders, arm flexors, elbows, legs and hips.
Saltin references a study which showed that, among a population of nursing home residents, “a high-intensity progressive regime of resistance-exercise training improves muscle strength and size in frail elderly people”.
Also speaking at the conference was Dr Nicola Crabtree, a research scientist at Birmingham Children’s Hospital. For the past 15 years, Crabtree’s work has centred on bone development in healthy children as well as those with chronic disorders such as Duchenne muscular dystrophy.
Crabtree was keen to stress how crucial weight-bearing exercise is in the development of healthy bone structure. In children and adolescents, weight-bearing exercises are those which use the child’s own body weight such as running, skipping, jogging, hopping and particularly stop/start activities such as tennis and rugby.
As a thermostat registers heat and responds to changes in temperature accordingly, “within the bone there are mechanisms that sense how it is being loaded and the bone responds to that”, says Crabtree.
“Bone has a ‘mechanostat’ which responds to load and sends messages to create more bone to make the bones stronger.”
She adds: “Vigorous activity needs to be weight-bearing activity. If you can imagine playing tennis or rugby, stop/start games are good because the bone responds to forces – the more you load it, the more bone you will create.”
Crabtree says it is important that young people continue to exercise in their adolescent years, when bone growth is at its highest, and that females in particular should be encouraged to exercise as they tend to become less active than males in their teenage years.
“It is important for children to exercise at all ages because of the many obvious benefits, but from a bone point of view it is important that children continue to do weight-bearing exercise into their teenage years and into adulthood in order to see the benefits. Unfortunately, teenagers, unless they are particularly sporty, tend to do less exercise.
“There is a very strong relationship between muscle and bone and the stronger your muscles are, the stronger your bones will be,” says Dr Crabtree. “You want to try to attain the highest peak bone mass in childhood so that, if you have a nice high point to start with later on, you have further to fall.”