Dr. Kevin Yip

Dr Kevin Yip
Orthopaedic Surgeon
MBBS(UK), FRCS(EDIN), FAM(SING), FHKCOS(ORTHO)

Featured on Channel NewsAsia

Exercise on Prescription

STRENGTH TRAINING
Muscle strength and endurance training can be controlled movement (machines), semi-controlled (cross wires) or free weights (dumb-bells or body weight). The choice of training method depends on the athlete’s aims and training background and the character of the injury. Free weights are more difficult to control than fixed movement training machines but add more stress to muscle and joint control. Complex muscle groups are more effectively trained using free weights, while isolated muscle groups may be efficiently trained
using machines.

To achieve an increase in muscle strength and volume, progression in training may be guided by the Repetition Maximum (RM) method. One RM is the maximum resistance the athlete can manage once, in a controlled manner or specific movement. If the movement can be performed up to, but not more than, 10 times it is called 10RM. A 10RM movement will result in increase in muscle strength and volume if performed for six weeks or more. Before initiating heavy resistance training such as this, the instructor must emphasise the importance of warming up and learning the correct techniques for the method and apparatus used for each muscle group. The initial increase in performance after this kind of training is neuromuscular:
the athlete learns how to use existing muscle fibres. To achieve a true increase in muscle volume and muscle hypertrophy, at least three months of regular training is required.

Training with lighter resistance and more repetitions will improve muscle strength and endurance. This type of training predominantly uses slow-twitch fibres but, if performed at higher speeds, fast-twitch fibres will be used. Muscular endurance is defined as the ability to perform dynamic muscular work, with constant generation of power, over a limited time. If using resistance training to achieve this effect in a specific muscle group, more than 15 repetitions in sets of three to five are recommended. Other types of endurance training include running, bicycling, skiing, cross-training and sport-specific activities. Endurance training can be performed daily providing its intensity and duration is progressively and reasonably increased.

Most injuries due to over-use are caused by ‘too much too soon’. Strength training is best done not more than two to three times a week, with at least one day of rest between each session, but endurance strength training can be done daily. Most muscle strength and muscle endurance exercises are a combination of controlled, slowly executed concentric (where the muscles are shortened and contracted) and eccentric (where the muscles are extended and contracted) muscle contractions. Athletes must rest properly between each set of repetitions.

Eccentric muscle strength is about 40 per cent greater than concentric. Concentrating on eccentric muscle training can increase resistance and enhance the effect of training. An athlete who can perform an eccentric
manoeuvre three to five times can perform the same manoeuvre concentrically without ever having trained for it. This kind of training has been shown to be effective for over-use injuries such as chronic Achilles tendinosis.

FLEXIBILITY TRAINING
Flexibility is defined as the active or passive range of motion of a muscle group. A limitation in muscle flexibility can be due to muscle tightness, cramps or a restriction of joint motion. The underlying cause of restricted flexibility or joint motion must be defined before a treatment can be recommended. The normal flexibility of different muscle groups is sport-specific. For example, a ballet dancer can usually take their foot, with the leg straight, right up to their shoulder, while a marathon runner may be able to lift the straight leg to only 60 degrees. Symmetrical, bilateral apparent muscle tightness, which does not cause symptoms, may be considered as a functional adaptation to the sport being performed. However, if there is an obvious asymmetric flexibility or the athlete’s movements are painful, mobilisation or other treatments may be indicated. Tight thigh muscles (hamstring) and hip-flexing (iliopsoas) muscles can not only cause pain in those muscles but also back problems, disturbed core stability and similar symptoms. Tight calf muscles may prevent squats, whereby weight will be transferred to the lower back, causing pain there. Chronic muscle tightness can cause fatigue, pain and dysfunction. However, hypermobility and excessive unrequired flexibility is not to be preferred: stretching can cause as many problems as it can solve. There are different types of stretching but the difference in effect among the various methods is small. The most important thing
to make the stretching as effective as possible is that the injured player ‘finds’ the middle of the muscle bulk they need to stretch. Stretching in this position should be held for about 10 to 15 seconds, followed by a few seconds of relaxation, repeated two to three times. (Interestingly, animals like dogs regularly stretch
their legs for one to two seconds only.) Stretching should always be performed in warmed-up muscles.

PROPRIOCEPTIVE TRAINING AND CORE STABILITY TRAINING
Co-ordination, balance, proprioception and core stability are terms frequently used in sport but rather difficult to define. They involve the ability to perform, or regain, controlled movements, in a sport-specific, safe and precise way. We cannot pin-point each and every control mechanism but there is lots of experience
to apply to sport. Tai chi is an excellent example of a method that aims completely to regain full body and mind control, so essential for elite sports. Martial arts and dancing focus on this type of training, which is a key to successful performance. Unfortunately, most contact sports such as soccer, rugby and ice hockey often neglect this type of training. For years I have tried to convince physiotherapists and coaches to learn from this: not only would it reduce the number of injuries and their consequences, but it would enhance performance and their players’ ability to undertake effective rehabilitation when injured.

SPORT-SPECIFIC TRAINING
The aim of rehabilitation is to restore a sport-specific function to, or above, preinjury levels. In cricket it could be the perfect bowling action, in tennis the serve, in baseball the throw, in football ball control or in gymnastics landing. This type of training requires knowledge and understanding of the sport’s specific demands and is usually prescribed and supervised by a sports therapist in close collaboration with a coach. After surgery or long immobilisation, this final stage of rehabilitation training is the most time-consuming and risky. In the final stage of rehabilitation after healing of an injury, functional training back to full performance level must be gradual, over a period of time that corresponds to the functional requirements of the muscles and the healing process of the under lying injury. This period could vary from a few weeks after a simple ankle sprain to a year after complicated knee surgery. The training has to be specific and, preferably, performed in a controlled environment. Returning too soon to full-time play will inevitably result in further or new injuries. Objective performance scores, specific for the sport, are very valuable but poorly developed. I have tried to develop such scores for professional rugby and soccer and their validity is improving. One of the main reasons for the difficulties of objective scoring is that the functional scores used by orthopaedic surgeons or physiotherapists are developed for the general population, ranging from recreational athletes of all age groups to elite athletes from varying sports. A high shoulder or knee score compared to the general population may not indicate it is safe for a professional soccer or rugby player to return to the game. Another reason is that a goalkeeper or striker in soccer, a winger, prop or full-back in rugby or a bowler or batsman in cricket may perform on the same level in the same team but the consequence of a low or high score may be very different for each of them. The evaluation of training outcomes is currently being investigated intensively.

Hopefully, more specific scoring systems for different injuries and sports will soon be available. Until then, we have to trust in our doctor’s experience and in close collaboration between the parties involved. Please call us at +65 9724 1219 (24 hrs) for an appointment.

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