STRENGTH TRAINING AND CP
All human movement, from the blinking of an eye to the running of a marathon, depends on the proper functioning of skeletal muscle and its strength.(5) Why do we need strength? Does a person with CP need strength training? These are some of the questions that we ask ourselves as parents and therapists. The answer to the first question is simple. Without strength we are unable to live. Each movement of our body depends on muscle strength. Without strength we are unable to eat, talk, walk, move and breathe. Strength of the muscle is essential to perform daily activities and learn new functions. We can survive without endurance, speed, and flexibility, but we cannot without strength. Very often we forget about its importance.Is strength training important for CP? Muscle strength is even more crucial for individuals with a disability than for those without. It has been confirmed by studies and clinical experience. Many times to help our children we try new methods of therapy involving sophisticated technology, medication and surgeries. We are able to use surgical procedures to decrease mm tone and improve alignment of the bones. It is great, but very often not enough to learn a new function (walk, roll, sit). To learn those skills, we need to develop strength to control the muscles and the body. In this article I will present existing misconceptions about strength training. I will describe very important facts about the development of strength in young individuals, and explain the success of intensive therapy programs. "Previously children with CP were not encouraged to strength train because it was felt this would increase spasticity and reduce flexibility, which would lead to the worsening of deformities and walking problems".
(1) Misconceptions Of Strengthening Programs:Many specialists still believe that strength training is not appropriate in individuals with cerebral palsy because:
Weakness is not a significant functional problem for them.
An increase in strength will not improve function.
Most of them cannot control their muscles sufficiently to train them .
Increased strength will increase spasticity.
Strengthening programs result only in hypertrophy of the muscles, and it does not effect the nervous system.
Another misconception involves the confusion about the difference between weight (strength) training and weight lifting.
(2) Facts:Dispelling these beliefs, many recent studies have demonstrated that:
Even mildly affected persons with CP have significantly reduced muscle strength, with the degree of weakness even greater in those with greater neurological involvement. In fact, weakness appears to have a stronger relationship with the level of motor functioning than other common symptoms such as spasticity or muscle tightness.
Individuals with CP can increase strength and improve passive motion through weight training.
Individuals with CP can increase strength in most if not all muscles at the same rate as persons without a brain lesion. Most importantly, strength training programs can produce positive changes in walking ability and in the performance of other motor tasks. There is evidence of a relationship between lower limb strength values and motor abilities. An increase in strength of one muscle group does not change the outcome of function, but improvement in strength of more muscle groups will result in significant improvement of functional skills.
No evidence exists to support the claim that strengthening exercises will increase spasticity. Strength training is perhaps most effective when performed in conjunction with other types of activities, exercises, or therapeutic interventions. In 1956, Massey and Chaudet demonstrated that heavy resistance training does not cause a decrease in flexibility. Spasticity has not been found to increase with strength training in the research done by Damiano, Mac Phail and Holland.
Weight (strength) training for children is based basically on resistive exercises using thier own body weight instead of lifting heavy weights. Our children are constantly doing resistive (strengthening) exercises using the weight provided from the child's own body. When a youngster does a push up, he lifts 60% of his body weight. If the child weights 50 pounds, he will lift 30 pounds performing push ups. Weightlifting, on the other hand, is a competition where participants lift as much weight as they can at one time.
(3) Strength Development:For many years , strength gains were assumed to result directly from increases in muscle size (hypertrophy). Current research (Meredit, Frontera) proved that prepubescent strength gains are accomplished largely without any changes in muscle size.
Young individuals develop strength through: - Improved motor skills coordination. - Increased motor unit activation. - And other neurological adaptations.
"During the first several weeks of resistive training, gains in strength are almost exclusively neural in nature, meaning the body is learning to recruit the correct muscles in the proper sequence while inhibiting unnecessary muscle recruitments. The physiologic changes, such as an increase in contractile proteins, stored nutrients, and anaerobic enzymes, take several weeks to develop. Once the neurologist "learning" phase begins to diminish, remodeling of the muscle is beginning to take place and strength gains continue". (LeMura) During the first 2-4 weeks strength gains can be achieved without structural changes in the muscle, but not without neural adaptation. There are more neuro-functional adaptive changes than structural changes within the muscle. Thus, strength is not solely a property of the muscle rather it is the property of the motor system.
Also, during the first weeks of strengthening exercises there is a reduction in the coactivation of other muscles (muscle synergies, pathological movements). It results in a decrease in energy expenditure, movement control improvement, and at the same time it leads to a decrease in mm spasticity (functional) resulting in functional improvement (or a great condition to achieve functional improvement).
After 4 weeks of resistive training, gains in strength are gradually achieved by increased size of the muscles (hypertrophy). The initial neural contribution to increase strength diminishes. At this time we will not notice further dramatic changes to the neuro-motor system of the body. Changes will be more specific and related only to the musculo-skeletal system.
(4) Intensive Exercise Methods:Resistive training can induce adaptive alternations in nervous system function, along with changes in the morphology and architecture of the trained muscles. Resistance training that results in both improved neural function and gains in muscle mass will benefit not only athletes, but also aged individuals and individuals with neuro-motor disorders. This will provide an effective way to improve everyday physical function. These findings help us to explain the success of the new and popular intensive treatment programs for Cerebral Palsy (e.g. Suit Therapy).Very characteristic of these methods is the short time of duration (2-4 weeks) and high intensity of the exercises (volume, frequency, resistance).
During 2-4 weeks of intensive therapy sessions, young individuals with CP perform resistive exercises 3-4 hours per day, 5-6 days per week. Very often after this short period of treatment, these individuals present significant functional improvement. Based on the theory of strength development, the functional improvement occurring after a short period of strength training is related to motorneurological changes. In a short time individuals with CP improve movement control, balance and coordination. Often they are able to perform functional skills that they were not able to do before (sit, roll, walk).
This improvement is caused by adaptive changes that occur in the nervous system in response to strength training. Electromyogram studies have indicated other adaptation mechanisms that may contribute to an increased efferent neuronal outflow with training, including increases in maximal firing frequency, increased excitability, decreased presynaptic inhibition of spinal motor neurons, and downregulation of inhibitory pathways. Short term resistance training has been reported also to induce hypertrophy of slow and fast muscle fibers, induce alternations in muscle fiber architecture and fiber type distribution, and other morphological changes.
Resistance training creates many other positive adaptive morpho-functional changes in other systems of the body (skeletal, cardiopulmonary, endocrine, etc.). More information about those changes are included in the bibliography recommended at the end of this article.
(5) Summary:To summarize, strength training in CP results in strength gains that are similar to those seen in persons without a central nervous system lesion, and produce positive outcomes in motor performance and functional skills.
For many individuals with cerebral palsy, strengthening exercises are important for their well-being. It allows them to maintain physically active lifestyles and overcome daily barriers. For many others, the improvement in functional skills achieved secondary to strength training allows one to perform for the first time in life new activities never done before. Secondary to improvements in strength, some individuals become more independent in daily life.
I believe that all the information and facts presented here are convincing enough for parents and therapists to make it imperative to incorporate strengthening exercise programs in the life of each individual with cerebral palsy. Facts About CP & Strength:
Generally individuals with CP are weak.
Spasticity is not related to mm strength.
Strength in CP is directly related to function.
Strengthening does not increase spasticity.
The energy cost of walking in children with CP can be up to three times greater than children without CP
Children with CP complain of fatigue at a very low exercise intensity
Excessive coactivation within and between body segments could be responsible for the high energy cost of walking in children with CP.
No comments:
Post a Comment