Why Kids Shouldn't Run Marathons

Kids can be very good runners. They are more often slim and lean with good power/weight ratios. A proportion have the focus and competitive instinct that aides training. They also have the time and likely support of parents, teachers and coaches who see sport involvement as better than the “alternative” activity options at this age

The big problem with kids, however, is their bones. Because they are still growing, their bones have growth plates composed of cartilaginous materials at either end. These growth plates allow new bone to form and hence the bone to grow in size and length. Once the growth plates fuse, the bone becomes solid and no new growth can ever occur.Growth plates are weaker than the bone around them and are prone to injury, especially when the growth plates are active during growth spurts.

Kids are susceptible to a whole group of injuries that adults can’t get and these are quite common. Of these, the most common growth plate injury is “Osgood Schlatters” disease, an irritation of the growth plate of the tibial tendon. This is the big tendon off the bottom of the kneecap, which attaches to a bony prominence on the upper front tibia (shin bone). This has a small growth plate that becomes inflamed, swollen and painful. It is very common in soccer players as kicking, especially, irritates it. It is also common in runners, jumpers and netballers. Like most growth plate injuries, it will settle with rest and a reduction in the amount of aggravating exercise. Typically, it recurs over a period of one to two years over the period of rapid growth in the pre-teen when the growth plate is most active and vulnerable.

The next most common site for growth problems is the heel. The Achilles tendon attaches to the heel bone with a growth plate underneath. If this becomes irritated and tender it is called “severs” disease. In a similar fashion, it settles with rest and reduction in activity although heel raises and orthotics may be helpful.

Not all growth plate injuries are so benign. The hip in particular is prone to growth problems that are serious. “Perthes” disease is a failure of the head of the femur to properly form a spherical head for a proper hip joint, leading to long-term problems.

Also the growth plate under the ball joint of the head can “slip” either gradually or suddenly again with severe long-term results. Both conditions cause pain in the hip or groin and usually a limp are symptoms that should always be treated seriously in a kid of any age because if a diagnosis is not made, permanent joint damage is likely.

The spine is also prone to bone growth problems, especially the low back where incomplete formation of the spine aggravated by stress from hyperextension. This leads to a condition called “Spondylolithesis” Sports like gymnastics, fast bowling or even netball goal shooting where the spine is arched back may contribute to this, so again back pain in the growing person must be investigated.

Most of these injuries are caused by the overuse of a particular type of stress on a particular bone.

Running does involve considerable lower limb stress so the reason kids shouldn’t run marathons is because of the likelihood of growth plate injuries which are occasionally very serious.

Recommendations are that children should restrict running distances according to age.

Under 9yrs 3km
9-11 yrs 5km
12-14 yrs 10km
15-16 yrs ½ marathon
17-18 yrs 30km
> 18 yrs marathon

Kids that play lots of different sports also with lots of training are also at risk especially if all are similar in the way they stress body parts, ie touch and running. Ideally if kids want to do more activity they should add a sport that has different loading ie touch with swimming, so they are less likely to get growth plate injuries.

It’s also important that coaches are aware of all the child’s sports commitments. There is a case to be made for not doing all the training for all the sports in the active child. Parents also need to be aware that sport is good, but you can have too much of a good thing. They should not apply pressure on their child either overtly or covertly to achieve or train above what that child is comfortable with.

Once you are over 18 there are however no excuses for not running your marathon!