SPORTS REHABILITATION

efficient movement and has a key role to play in the restoration of function and the prevention of recurrence (21-23).

Due to their role in controlling and maintaining postures, stabiliser muscles are best trained using slow sustained contractions at low loads. When carrying out motor control training it is important to ensure that the specific muscles are appropriately activated and that compensatory strategies are avoided. For example, during shoulder rehabilitation it may be necessary in the early stages to place the athlete in a position (eg. prone lying) where they find it easier to activate the lower fibres of trapezius while simultaneously avoiding overactivity of the upper fibres of trapezius. The exercise may then be progressed by getting the athlete to perform slow sustained contractions of the affected stabilisers in more challenging positions that reflect those adopted in their sport. The importance of using sport-specific positioning when training motor control should not be overlooked.

A number of authors have reported a relationship between altered motor recruit- ment efficiency and proximal positioning. For example, Ginanneschi et al (24) have observed that distal upper limb control is significantly altered at various degrees of shoulder abduction. Similarly, the maximal velocity of elbow extension has been shown to be significantly reduced when combined with trunk flexion or extension (25). This is highly applicable to rehabilitation and highlights that effective sports rehabilitation must incorporate training in sport-specific positions in order to enhance performance and provide

protection from reinjury. In light of this it is suggested that motor control training is advanced from neutral positions in the early stages to increasingly challenging movements performed in less stable positions as rehabilitation is progressed. There is little rationale for continuing to perform motor control training in lying when the athlete's sport requires them to maintain an upright stance. The relationship to the introduction of unstable surfaces during sensorimotor training is clear and therefore it may be reasonable to perform exercises that simultaneously stimulate sensorimotor function and motor control stability.

STRENGTH TRAINING Adequate strength is essential for effective and safe return to sport. Although strength can be defined as the ability of a muscle to generate force, it is also important to appreciate the subqualities of strength and its relationship to functional performance parameters such as speed and power. Subqualities of strength are summarised in table 2, while table 3 relates functional parameters of power and muscular endurance. During the recovery phase of rehabilitation, strength training should concentrate on the restoration of strength deficits incurred as a consequence of injury. It is important to appreciate that strength loss following injury may be due to a number of factors and that these factors must be addressed in order to effectively restore muscle strength.

There are two main ways in which strength loss may occur: ■ Structural - in which weakness is due to a reduction in the size and number of

TABLE 3: FUNCTIONAL PARAMETERS RELATED TO STRENGTH Component Power

Definition

Product of strength and speed (ie. the ability to generate maximum force in the shortest period of time)

Reactive power Cyclic power Acyclic power Muscle endurance

Acyclic endurance Cyclic endurance

www.sportex.net

The ability to generate the force of jumping immediately following landing

Power that is generated during cyclical activities such as sprinting, cycling - closely related to speed

Power generated on one occasion eg. throwing and jumping The ability of the muscle to generate force for period of time

available muscle fibres

■ Neuromuscular - which relates to diminished recruitment of motor units within the muscle. Following injury, strength loss is generally due to a combination of each of these factors and as a result, effective rehabilitation programmes must incorporate strategies to address both the structural and neuromuscular elements of strength loss. Lieber (26) has suggested that during the first two weeks of strength training only 20% of the increase in strength may be attributed to structural changes indicating that initial strength gains are primarily due to neuro- muscular adaptations. In light of this, and considering that following injury neuromuscular ability can be significantly diminished, it is reasonable to suggest that, as for sensorimotor training, it may be more effective during the early stages of rehabilitation to carry out strengthening exercises 'little and often' in order to avoid nervous system fatigue and to facilitate neuro- muscular adaptations.

During the early stages of the rehabilita- tion it may also be necessary to employ simple strength training strategies such as isometric training. Isometric contractions are those during which tension is developed in the muscle without any change in muscle length. While isometric strengthening exercises tend to be less functional, they have an important role to play in the early stage of rehabilitation to encourage facilitation of inhibited motor units. They may be particularly useful for those athletes whose sport involves maintaining a specific posture for

Sports involving component Weightlifting, rugby scrum

Athletics - jumps, volleyball, basketball, gymnastics

Sprinting, swimming, cycling, rowing Throwing events, jumping, gymnastics

All sports requiring prolonged or repetitive muscle activation

Ability to generate and maintain force for long period of time Wrestling, gymnastics Ability to generate force repeatedly over an extended period

of time

Endurance events: swimming, cycling, rowing, cross-country skiing,

13