Physiotherapy and Rehabilitation

Stretching

Many people confuse stretching, flexibility, and mobility. Stretching is an intervention, flexibility is the limits of range of motion (ROM) due to muscle-tendon, and mobility is the limits of ROM due to capsule-ligaments. The effects of stretching depend on whether one is trying to affect the muscle-tendon, or the capsule-ligament. This topic focuses only on muscle-tendon.

Pre-activity stretching

ROM is increased. Increases in ROM are superior if warm-up is done prior to stretching.
The increase in ROM is partly due to decreased stiffness of the tissue, and partly due to a decrease in the sensation of pain associated with the stretch.
A single bout of stretching decreases the strength of tissue in animal studies in the immediate post-stretch period.
The results below are unchanged whether or not warm-up is done prior to stretching:
- Decreases tests of performance for strength and jump height in every study (over 20). Running speed changes are conflicting across different studies, but different methodologies prevent definitive conclusions.
- No effect on overall injury rate when performed regularly. Some authors suggest the risk for some injuries are reduced with stretching before exercise. If so, then other injuries must be increased as the total number of injuries is unchanged.

Daily stretching (not pre-activity)

ROM is increased with daily stretching.
The results below are unchanged whether or not warm-up is done prior to stretching:
- Daily stretching increases strength of tissue in animal studies.
- Three studies have shown an approximate 20% reduction in injuries with daily stretching, but 2 of these had small sample sizes and did not achieve statistical significance.
- Tests of performance for strength, jump height, and running speed are improved with daily stretching.

Dynamic stretching

Dynamic stretching is usually described as moving the joint through its functional ROM expected during activity, first slowly, and then more quickly; forcing a muscle into a lengthened condition when it is being contracted and relaxed is usually called ballistic stretching. Commonly described, ‘dynamic stretching’ activities include squats, push-ups, skipping, and hopping. With this definition, dynamic stretching is really just a form of warm-up and would be expected to have the same effects. There are no studies comparing the effects of dynamic stretching to traditional dynamic warm-up.

Additional comments

If daily stretching outside periods of exercise is protective against injury, but stretching immediately prior to activity is not associated with a reduction in injuries, it must mean that stretching immediately prior to activity removes the protective effect of daily stretching, i.e. it is harmful. However, because the overall effect of importance to the subject is whether the risk is increased when they stretch vs. when they don’t stretch, this point is purely academic.

Balance and proprioception

Over the last 40yrs, we have recognized that balance and proprioception are important in the prevention and rehabilitation of injuries.

Definitions

Balance: ability to maintain a given posture.
Proprioception: (used interchangeably with kinaesthesia) control of movement and posture. There are 4 contributing sensations:
- Limb position and movement.
- Muscle effort, tension, heaviness, and stiffness.
- Timing muscle contractions.
- Body posture and size representation across more than one joint.

Many different physiological processes contribute to proprioception. These include afferent nerve fibres from:

Musculoskeletal: muscle spindles, tendon organs, joints (ligaments, disks, and menisci).
Other: cutaneous, pain fibres.

Biomechanics

The body sways to-and-fro in all directions. When the body’s centre of pressure is not immediately under its centre of mass, the body moves. Resting muscle tone provides stiffness that prevents some motion. Muscles dynamically contract to restore position following perturbations.

Clinical research

Patient relevant outcomes include:

Falls, and/or fall causing injury.
Fear of falling: someone with poor balance may alter behaviour to avoid falls. This can have a dramatic impact on quality of life.

Measuring proprioception

Because proprioception is a composite of 4 different sensations, a true measure of proprioception is complex and requires sophisticated laboratory equipment. Most clinical studies that evaluate ‘proprioception’ are actually measuring balance. Some simple ways people measure balance in healthy subjects for sport medicine studies include (in order of difficulty):

Standing on one leg
Standing on one leg with eyes closed.
Standing on one leg on a foam pad.

Although none of these methods actually has very good reliability, balance still seems to be a very important predictor of injury. How? Reliability is a measure of ‘noise’. Injuries are a measure of ‘signal’. As long as the signal-to-noise ratio is high, it is irrelevant how large the absolute value of the noise is.

Role for primary prevention

Exercises designed to improve proprioception have been successful in the primary prevention of:

Falls in the elderly.
Anterior cruciate ligament tears in girls.
In a recent study, proprioceptive exercises for the ankle reduced ankle injuries by 20%, but the results were not statistically significant.

Role for secondary prevention

Many studies show proprioceptive exercises are effective in reducing re-injury rate following an ankle sprain. They may also be effective following anterior cruciate ligament reconstruction.

Other benefits

Proprioceptive exercises are effective in the elderly, frail elderly, those with Parkinson’s disease, and patients post-hip fracture. Despite the lack of research on other musculoskeletal topics, the basic science and theoretical evidence suggest that it is a promising intervention with very low risk.

Plyometrics

Purpose

Plyometrics train power. Power is the ability to generate force in a very short period of time (e.g. jumping, sprinting). One study suggested that plyometrics are used by 90% of USA Division I strength and conditioning coaches and another suggested they are used by 94% of National Football League coaches.

Definition

Plyometrics is a very specific type of exercise. Some basic terms:

Concentric exercise: the muscle shortens as it generates force.
Eccentric exercise: the muscle lengthens as it generates force because it is unable to overcome a greater force being applied to it.

Plyometrics refers to any exercise where the muscle goes through an eccentric contraction-concentric contraction cycle repeatedly at a fast rate. In physiological studies, it is also called the stretch-shortening cycle, but those studies often limit themselves to one cycle—plyometrics requires repetitions.

Plyometric examples

Jumping up and down.
Push-ups and clap hands when body is high.

Theoretical reasoning

Plyometrics is based on the specific adaptations to imposed demand (SAID) principle.
If one trains strength, strength is increased, but there are very small gains in power and endurance. Weightlifters are not marathon runners and marathon runners cannot lift heavy weights.
Plyometrics should be used for jumping sports or when acceleration is essential (sprint start).
There are no meta-analyses or systematic reviews comparing plyometrics with other types of training. Some studies show it to be superior while others show no difference. The opposing results may be due to differences in populations and/or required power output.

Safety

Plyometrics represent a high intensity workout.
As exercise intensity increases, the stress applied to muscles, tendons, and ligaments increases.
If the stress applied to a tissue is greater than it can absorb, an injury occurs.
As with all exercises, the best way to prevent injury is to start slowly and increase gradually.
Some reviews now suggest that plyometrics should be an important part of injury prevention programs.

Proprioneurofacilitation (PNF)

Types of PNF stretching

For each of the examples, the hamstring muscle is being stretched. Different authors use different nomenclature for the same procedures. I have chosen the one that seems reasonable if one considers the hamstring as the agonist muscle and the quadriceps is the antagonist muscle. The subject is lying on the floor on their back.

Contract-relax (CR): the leg is lifted passively by a partner. The subject contracts the hamstring muscle for a short period (2-10s) and then relaxes the muscle. As the muscle is relaxed, the partner passively raises the leg higher to increase the stretch on the agonist.
Contract-relax-antagonist-contract (CRAC): this is the same as the CR method, but following the passive stretch, the quadriceps is actively contracted by the subject.
Agonist-contract-relax (ACR): this is a confusing name. In fact, the subject contracts the antagonist (quadriceps/hip flexors) to stretch the agonist (hamstring), and the muscle is supported during the rest phase. A variation termed hold-relax (H-R) is to contract the hamstring before resting.

Experimental evidence

Since being widely promoted in the mid-1970s, there have been several studies examining the effectiveness of PNF stretching. The results are:

With respect to ROM, studies suggest ACR and CRAC (these two have not been directly compared) superior to CR, which is superior are H-R, which is superior to static stretching.
There is no inhibition of muscle reflex activity. In fact, the EMG of the stretched muscle is increased with PNF compared with static stretching. The mechanism for the increase in ROM remains to be determined.
There is a change in the muscle visco-elasticity with PNF stretching for the immediate period following the stretch, but there are no long-term changes in visco-elasticity even though ROM increases. These changes are similar to those seen with static stretching.
Taken together, the above suggests that PNF stretching has a greater analgesic effect than static stretching and this may be the reason for the increased ROM.

Taping and strapping

Taping and strapping refer to the use of bandage material wrapped around a joint with the objective of improving stability of that joint. Taping refers to the use of an adhesive tape and strapping refers to the use of non-adhesive wrap.

Background

There is both static and dynamic stability of a joint:

Static stability (or mechanical instability) refers to passive mobility of a joint. Typically, this is tested by a second person while the subject’s muscles are relaxed. Mainly ligaments provide stability.
Dynamic stability (or functional instability) refers to the mobility of a joint during active motion. Mainly muscles provide stability.
Example: The normal AP movement observed in the knee with the Lachman’s or Anterior Drawer test, tests static stability. This movement does not occur during walking or running (i.e. dynamic stability).
Dynamic stability is more clinically relevant than static stability and measured by joint displacement following a sudden force (e.g. trapdoor). Injury or re-injury rate is even more clinically relevant.

Effectiveness

Most of our knowledge comes from ankle studies or anecdotal experience.
For large joints, taping and strapping have lost 20-50% of their effect on static stability within 15-20min. Whether this is true for small joints exposed to lesser forces remains to be determined.
Taping and strapping appear to improve dynamic stability in most studies. This is associated with an increase in resting electromyography (EMG). Improved muscle activity results in increased stiffness of the joint (should protect against injury).
Clinical trials suggest taping and strapping are effective in preventing ankle injuries.
Anecdotal evidence suggests that they are useful to limit motion for injured small joints, such as wrists, fingers, toes.
Some clinicians will also tape acromio-clavicular joints, knees, and shoulders. The effectiveness for these joints is controversial and should be evaluated on an individual basis, i.e. tape the joint and if the patient feels it allows them to compete with less pain it is effective for that patient.
Taping is also used to limit joint movement to reduce stress on tendons in patients with symptoms (e.g. Achilles tendonopathy, anti-pronation taping). The effectiveness of these methods in general has not been well studied. That said, these types of taping should be evaluated using n-of-1 trials. Simply put, make decisions about a particular individual by measuring pain with and without tape repeatedly in that individual.

Potential deleterious effects

There are no studies on long-term effects. Probable potential deleterious effects include:

Allergic reaction to the adhesive used in tape. Pre-wrap and hypoallergenic tape may reduce this problem.
Tenosynovitis if tendon is superficial. Small foam pads placed over the tendons may reduce this problem (e.g. anterior tibialis and Achilles tendons for the ankle).

Principles of rehabilitation

The principles of rehabilitation following any injury can be broadly classified into three phases—early, middle, and late. These stages are not mutually exclusive. Short- and long-term goals should be defined for each athlete and reviewed at appropriate time intervals, depending on the injury. Appropriate clinical markers should be used to define the progression of rehabilitation.

Athletes should not be allowed to progress until they have, ideally, completed each stage without difficulty. Rehabilitation ladders or recipes should be used only as guidelines and each athlete should have a customized sport-specific and individually-negotiated rehabilitation plan.

Aerobic fitness and sport-specific motor control and co-ordination must be maintained where possible throughout rehabilitation.

The plan should be designed around what the athlete can do, rather than what they cannot.

Early phase (protection of the injured part)

Strapping or bracing the injured part to prevent unwanted motion.
Non- or partial-weight bearing with crutches may be necessary with lower limb injury, and a resultant antalgic gait. It is important to normalize gait.
Relative rest.
Protect, rest, ice, compress, elevate (PRICE).

Middle phase

Range of movement and flexibility: aim to restore full range of joint motion (physiological and accessory) and muscle length.
Strength and conditioning: motor control and re-education, strength, power, and endurance.
Proprioception: aim to restore normal kinaesthetic awareness to the injured part.
Progression of proprioceptive exercises:
- Static dynamic.
- Conscious automatic.
- Decrease the base of support.
- Decrease visual input.
- Functional.