All top class sports men and women will plan their training so that foundation training (cardiovascular conditioning, general strength) is followed by a period of specific strength, prior to highly demanding speed, power and competition work. Woven throughout this progressive structure will be all the elements of preventive conditioning that each performer requires in order to minimise their injury risk.
As part of this approach, sports performers will set goals, and regularly assess both their success in achieving these goals, and undertake regular (at least three a year) assessments of general and sports specific fitness (endurance, speed, etc.). Most sports coaches and national governing bodies of sport can provide details and examples of programme planning, goal setting and assessment.
As a general guide to understanding training errors that result in injury, it is important to keep a training diary. This need only include brief details of the session (what you did, e.g. mileage/volume, speed/intensity, sets/reps, etc.) and the date and time you did the session. Should you succumb to an overuse injury, looking back through the diary can usually help you pinpoint what changed, and therefore what may have contributed to the injury itself.
Technique
A number of overuse injuries are clearly related to sports or exercise technique. Indeed, some injuries are even popularly named after their sport (e.g. tennis elbow). Often it is the repetition of an action with faulty technique that results in excessive load on tissues and subsequent injury. For example, tennis elbow is usually an injury to an extensor tendon of the wrist.
Sometimes it is triggered off by a change in equipment (such as racket size, grip size or even string tension). However, it is often the result of a faulty technique (backhand, or top spin forehand). This should be checked and corrected with a tennis coach.
Similarly, a low elbow position in overhead activities (racket sports, swimming) can result in elbow or shoulder injury, excessive anterior tilt of the pelvis in runners can contribute to hamstring injury, and an incorrectly set cycle (handlebars) can result in wrist/nerve injury or knee injury (seat height/position).
In every case of overuse injury, it is always worth considering whether sports technique is as good as it can be. This is also true of exercise technique in the gym (whether resistance training or stretching) and advice should always be sought from a qualified instructor on how best to perform any exercise.
Furthermore, it should be remembered that skill breaks down with increasing fatigue, so the last few repetitions of any exercise in the gym should be watched most carefully and should be as technically correct as the first few.
Warm up
Prior to engaging in strenuous exercise, training physical activity or competition a thorough warm-up is recommended. This is because many of the body's tissues (particularly muscle) respond better to loading when they are warm. The warming up process should include whole body exercise (jogging, cycling, the sport itself at low intensity) that increases blood flow to muscles and makes then more responsive.
The length of this warm-up phase will depend upon the ambient temperature (the warmer it is, the less time needed to become warm) and what is going to be done. All out sprinting for example, is extremely demanding, and warming up to sprint is not just a case of increasing temperature and local blood flow, but of gradually preparing the muscles and joints to generate maximum forces very quickly. Consequently, movement specific or sports specific drills will form part of the warm up phase, along with flexibility work aimed at taking muscles and joints through the range of motion that will be required during the activity or sport. Warming up for an exercise session may take as little as ten minutes, whilst warming up for demanding sports training or competition can take 30 minutes or more.
At the end of every training session, all sports performers will warm down, bringing their body back down to normal, usually through low intensity activity, followed by flexibility exercises. As with the warm up phase, the time course is similar according to what has been done.
The Intrinsic injury Risk Factor
The intrinsic injury risk factors are those that the individual brings with them to the sport, exercise or activity. These include factors such as the shape and structure of the major joints. For example, feet which pronate ('roll inwards') or have a poor arch often contribute to lower leg, shin and knee conditions in runners, as do 'knock knees' (genu valgus) or 'bow legs' (genu varus). Other injury risk factors include:
- Leg length discrepancy
- Muscle weakness or imbalance
- Decreased flexibility
- Joint laxity (that is, not being able to control and stabilise joints throughout their full range of motion)
- Gender (there are potential gender differences that make women more susceptible to certain knee injuries)
- Age (tendons degenerate with age, so an acute rupture is more likely in the older athlete. Similarly, certain injuries only occur in children)
- Being overweight (since this increases the load on muscles, tendons, ligaments and joint structures during weight bearing activities)
As a consequence, these potential injury risk factors may well be evaluated during a biomechanical assessment, postural or gait analysis by the appropriately qualified professional.
Leg length discrepancy
It is not unusual for most people to have one leg longer than the other. As with joint malalignments, the effect of a leg length discrepancy from an injury perspective is the potential for a change in the forces going through muscles and joints. With a structural difference in leg length of at least 1.5 cm, it is not uncommon for the pelvis and spine to compensate for this difference.
Usually, the pelvis tilts sideways (laterally) since one side will naturally be higher than the other. In turn, this results in a lateral 'kink' in the spine known as a scoliosis. The same situation can also occur even if the legs are the same length because of poor posture. In this case, the habitual posture results in a relative shortening of certain muscles and a relative lengthening of others. This is known as a functional leg length discrepancy.
Again, such a biomechanical compensation because of a real or functional leg length discrepancy is not necessarily a problem. However, leg length discrepancies can alter the mechanics of the pelvis so that the normal stabilising and controlling action of specific muscles is altered. Excessive anterior and lateral tilt of the pelvis is associated with recurrent hamstring strains, lumbar and sacroiliac (lower back) problems and inflammation of muscles around the hip such as the tensor fascia lata.
If such altered biomechanics are identified as contributing to an overuse injury, a common approach is first to treat the injury then modify the mechanics through specific strengthening (of muscles that are weak) and stretching (of muscles that are restricting movement) exercises. Orthotics may be prescribed in certain instances.
Muscle weakness and imbalance
Because muscles can exert a force or pull on bones, they can pull them into certain positions, usually as a result of habitual (everyday) postures. Finding themselves in a shortened or lengthened position for long enough, muscles will respond by becoming shorter or longer. This changes the forces acting on bones and joints and usually results in an obvious postural change. For example, sitting at a desk all day in a slumped position with shoulder forwards often results in lengthened, weak muscles between the shoulder blades and upper back with a relative shortening of the muscles of the front of the chest.
This leads to a change in the mechanics and action of the shoulder joint, neck and upper spine and an increased risk of injury if this posture is taken into sporting or physical activity. The correction of this postural imbalance is usually straightforward. Specific exercises will help, but most important is the adoption of a more efficient everyday sitting posture.
In sport and physical activity, it is similarly possible to develop muscle weaknesses or imbalances that increase injury risk. For example, in racket sports the action of serving and smashing can lead to a relative imbalance of specific muscles at the shoulder joint (those that rotate the arm inwards) that place the joint at a massively increased risk of injury. Preventive conditioning aimed at strengthening muscles behind the shoulder (responsible for rotating the arm outwards and controlling the rhythm and movement of the shoulder blade) can reduce the injury risk dramatically.
Many shoulder joint problems have their origins in poor control of the shoulder blade (scapula) by the many muscles that are attached to it. This is due to the fact that the socket of the shoulder joint is part of the shoulder blade and can be badly positioned through poor scapular control. Injury occurs as a result.
Flexibility and joint laxity
Flexibility refers to the range of motion possible at a joint or throughout a series of joints. It is influenced by several factors, including the type of joint, its structure (e.g. the position of ligaments, etc) and the position and tension of the muscles and tendons that cross it.
A range of motion that is greater than that which is considered normal is known as hypermobility. A joint is 'lax' if the ligaments do not hold the bones and hence the joint together particularly well, allowing considerable joint play. It is not unusual for hypermobility and joint laxity to go together and the freedom of movement at such a joint means that it is far easier to sublux or dislocate this type of joint.
A good general level of flexibility is required in most sports and some sports and activities (such as gymnastics and ballet) require extreme ranges of motion. However, if the muscles cannot control the limbs and joints throughout this extreme range of motion and the joint is lax, then the risk of injury is greatly increased. The ability to control movement throughout its full range is often referred to as joint stability.
A history of joint dislocations (for example, at the shoulder) or general 'looseness' reported by a sports performer indicates that the joint may be lax and potentially unstable. Joint stability may be improved by developing the strength and control of specific muscles acting at the joint.
Malalignment
Everyone has a slightly different joint configuration that falls within a normal range. However, when bones and joints develop in certain ways, they are often referred to as being malaligned. At the foot and ankle, there are numerous shapes and configurations that a specialist (such as a podiatrist) may recognise and name. For example, at the ankle, there can be an increased 'inward' movement and a 'rolling' in of the foot, most noticeable when the foot contacts the ground during running. This is known as excessive pronation (hyperpronation).
In turn, this means that the forces going through the foot, ankle, knee and leg change. As a consequence, some muscles need to work harder than they would do normally (usually those of the lower leg) to control and stabilise the foot and ankle. In addition, some tendons are placed in lengthened or slightly twisted positions (such as the Achilles) as their muscles contract.
The end result of superimposing training on these abnormal biomechanical movements and stresses can often be an overuse injury. Overuse injuries associated with excessive pronation include stress fractures of the tibia, inflammation of the tibial periosteum ('medial tibial stress syndrome' often referred to as 'shin splints') and Achilles tendonitis. Furthermore, because excessive pronation can cause the lower leg to rotate inwards, this may change the forces that go through the knee and overuse injuries to structures of the knee (such as the patella tendon at the front of the knee, resulting in patellar tendonitis) may also occur.
Similarly, certain knee joint configurations commonly referred to as 'knock knees' (genu valgus) or 'bow legs' (genu varus) plus specific hip and pelvis angles can increase the risk of overuse injury. A hip joint that naturally rotates inwards (femoral anteversion) for example, or a pelvis that tilts forwards excessively (anterior tilt) can also contribute to overuse injuries of the knee and/or contribute to injuries to any of the many muscles attached to the pelvis, hip and thigh.
A pelvis with excessive anterior tilt usually leads to an increase in the curve in the lower back (lordosis) and occasionally a compensatory curve in the opposite direction in the mid-spine known as a kyphosis.
However, there are many sportsmen and women with less than perfect joint mechanics who do not suffer from overuse injuries. The important point is that if you suffer an overuse injury, particularly one that re-occurs, you should seek appropriate treatment. Abnormal lower limb biomechanics can often be improved through specific conditioning and rehabilitation approaches and/or custom made inserts (orthotics) once an athlete's gait and movement mechanics have been evaluated.
Gender
The generally wider pelvis of the female compared with the male means that the angle of the thigh relative to the knee is different. In turn, this means that the relationship between the line of pull of the front thigh muscles (the quadriceps) and the angle of the quadriceps tendon (patellar tendon) also differs. The greater the angle between the line of pull of the quadriceps and the patellar tendon (known as the Q angle), the greater the risk of injury at the knee during running and jumping activities.
