Monitoring youth athletes could reduce the risk of injuries
Many sports injuries – and the risk factors involved in developing them – are overlooked by coaches. In order to reduce injuries and dropouts, training should be more adapted to accommodate growth and maturity than is currently the case.
You have probably noticed this yourself: teenagers grow at different times and at different rates. Some quickly become muscular, others suddenly grow tall and skinny. Girls mature well before boys.
However; what if different parts of the body mature at different rates? If this is the case, the most vulnerable body parts, the weakest links, will also vary over time.
"This is something coaches need to take into account. At the same time they need to know which injuries are most common and have the greatest impact. There is a lot of room for improvement here.”
These are the words of Eirik Halvorsen Wik, who has been studying how various injuries can be linked to different risk factors during one’s adolescent years – or: how injuries can be linked to different stages of growth and biological maturation in elite youth athletes. When there are such differences in maturation within a group, we should not just place emphasis on age when putting together a team or a training group. We will return to that.
One of the aims of Mr. Wik's work has been to answer the question about whether or not the risk of developing injuries is associated with growth and maturation. There is a lot to indicate that they are. One of his findings is that skeletal injuries – one of the most serious types of injury – are under-reported.
Eirik Halvorsen Wik will be defending his doctoral dissertation on 10 June: «Injuries in elite male youth football and athletics - growth and maturation as potential risk factors»
Eirik Halvorsen Wik is affiliated with the Oslo Sports Trauma Research Center under the Department of Sports Medicine at the NIH.
For the past four years, Eirik Halvorsen Wik has been living in Qatar's capital, Doha, working with Aspire Academy, an elite national academy for talented boys between the ages of 12 and 18. He has studied sports injuries in football and athletics, specializing in sprints, endurance, throws and jumps. All these youth athletes have access to physiotherapists on a daily basis, so it has to be possible to record all injuries - both those less and more severe.
The main aim of the Oslo Sports Trauma Research Center with which Wik is affiliated in Norway is to prevent injuries. In order to know where to implement measures, it is necessary to know as much as possible about the injury patterns. This will allow for detection of injuries in the initial stages, implementation of injury-reduction measures – and to ensure continued development for the athlete concerned. This is important for individual progress, in order to prevent long-term complaints and possibly also for whether or not the athlete will be able to continue with his or her sport. It is also important for the team.
Some examples of injuries that can occur before the skeleton is fully developed, while a young athlete is still growing:
Osgood-Schlatter's disease is an irritation that can occur in the tendon attachment at the top of the tibia (lower leg), where the tendon from the thigh muscle is attached via the kneecap.
Sever’s disease (also known as calcaneal apophysitis) is an irritation in the attachment of the Achilles tendon to the back of the heel. The tendon is attached to the area around the growth plate of the heel.
Apophysitis or irritation of the upper attachment of the thigh muscles to the hip bone.
In this respect Wik has not only looked at the so-called incidence rate, i.e. how often an injury occurs, he has also looked at how serious the injury is: the injury burden (see the fact box).
"We discovered that skeletal injuries in particular are overlooked. These occur less frequently, so they disappear in the statistics, but they are serious for the athlete. If you look at total injury time, such injuries are more serious than previously reported. Relatively speaking, they are a greater problem in athletics than in football.”
Weakest links change
Skeletal injuries do not just include fractures, but also bone stress injuries and irritations to the growth cartilage (growth plates). Such injuries are often found close to where the muscle attaches to the skeleton, and this growth cartilage gradually hardens into mature bone with age. Unlike fractures, such injuries will often only cause pain, so the athlete is able to continue.
“In order to limit such injuries, we should not only take the pain seriously, we should also know that the typical locations of such injuries is age-dependent," says Mr. Wik. The heel is most likely culprit between the ages of 10 and 12-13, and the knee between the ages of 12 and 15, while the bones in the hip and pelvis for many is not fully developed until the age of 20. This applies to boys, while girls develop earlier.”
"But are the "weakest links" at any one time in one’s development individual as well?
"Yes, because the structures mentioned develop at such different times between individuals.”
Which injuries restrict athlete participation? - FOTBALL
The Doha study comprises football and athletics for boys between the ages of 12 and 18
Comprises 1,111 time-loss injuries, 92,828 hours of football, involving 301 players over 4 seasons.
Muscle and tendon injuries are most common, but bone injuries account for the highest percentage of lost days (one third), thus having a much greater impact on participation - they have the greatest "injury burden".
Injuries with the greatest impact on participation – injury burden (days lost per 1,000 hours):
Knee sprain: 46
Thigh muscle strain: 29
Ankle sprain: 27
Lower back bone stress injury: 13
Pelvis/hip/groin growth plate injury: 11
Athletics - please see below...
Can monitor growth and maturation
Eirik Halvorsen Wik believes that coaches need to take these changes in the injury pattern into account. However, if we know about the risk factors, then things do not need to be so difficult.
“You can monitor growth or maturation by recording the height of each individual athlete, for example, 3-4 times per year. When puberty and the growth spurt "takes off", we should be more careful with exercises that have a big impact, especially on the heels, knees and hips,” he says. “At the same time we should be careful about making sudden changes in the training load. Late maturing athletes may be particularly prone in this respect, because the demands of training and competition often increase while they are still in a phase with rapid growth and before they are mature enough to withstand the load.”
Maturation of young athletes can be monitored even more carefully if their so-called bone age is measured, but this requires more advanced equipment. At the same time it would probably be important for a coach to explain to the parents why he/she has adjusted a training programme.
"But that could be difficult, couldn’t it?" They are so keen to do their best at all times.”
“We need to explain why adjustments are important. If they are able to make individual adjustments, it would be a win-win for all concerned.”
Which injuries restrict athlete participation? - ATHLETICS
Comprises 290 time-loss injuries from 72,086 sessions involving 178 athletes over 5 seasons:
Bone injuries had the greatest injury burden, with 58 percent of all "days lost".
Injuries with the greatest impact on participation (days lost per 1,000 hours):
Thigh muscle strain: 15
Lower back stress fracture: 12
Lower leg bone stress injury: 7
Pelvis/hip/groin growth plate injury: 5
Knee growth plate injury: 4
Keeping an eye on maturation is decisive for retaining athletes in their sport. This is because young people grow and mature at such different times. A 13-year-old who matures early may physically be like an average 15-year old, who in turn could be like a "late bloomer" at the age of 17.
“Each individual should get the opportunity to compete or train with others at his/her own level, regardless of age, at least every now and then.” Mr. Wik believes that this can be motivating for both early and late maturing athletes, because they are able to pit themselves against others who are equally strong, in respect of both physical challenges and displaying their technical skills. “In some sports, such as martial arts like judo, they already use weight classes within wider age groups.”
However, he stresses that such juggling needs to be carried out carefully. "In this respect coaches also need to explain properly why they are doing it.”
He emphasises that these are ideas inspired by studies elsewhere and might well appear difficult in practice, e.g. for social reasons that might be experienced over time.
When Eirik Halvorsen Wik put together the injury records from the physiotherapists in Doha, he discovered huge discrepancies when he included all the injuries that required medical attention by a physiotherapist or a doctor (using a so-called broad injury definition). He warns that other studies may also suffer from the same problem:
"Accurate injury recording is decisive for preventing injuries."
"It turned out that different physiotherapists were reporting in very different ways – because they were using a so-called broad injury definition. The most motivated ones were recording almost nine times more injuries which did not impact on participation than the less motivated ones. This meant that the figures could not be used reliably.
From a methodological point of view, this is a very important finding in the Doha study.
"Fortunately: the physiotherapists’ records of the more serious injuries were much better since they were able to use a "narrower" injury definition: when an injury affects participation (time loss), they all recorded it in the same way."
Modifying training at the right time
In addition to the incremental maturation and the risk of developing injuries that change over time, Mr. Wik’s studies in Doha show that the injuries sustained by youth athletes occur more frequently with increasing age.
"As you get older, you also get heavier, stronger, and train and compete more, and there is an increase in the load, intensity and power. We have taken training time into consideration, but we haven't measured everything.”
Perhaps more obvious is the fact that the injury types sustained depend on the type of sport. Also in Qatar, sprinters are more likely to develop muscle injuries, throwers develop injuries in the lower limb cartilage and muscles in the upper body, long-distance runners suffer generally from bone stress injuries and jumpers often lose time to stress fractures. “But age and maturation also play a role in this respect. It's all about knowing your athlete and making adjustments at the right time.”