Effect of functional power training on the walking ability of children with spastic cerebral palsy in the age of 4 to 10 years

Introduction
Children with cerebral palsy (CP) is the largest group treated in pediatric
rehabilitation. Prevalence rates of CP are about 2 per 1000 births in Europe of
which 82% has a spastic CP. Motor impairment in CP is multi-factorial and
includes problems such as spasticity, coordination problems, loss of selective
motor control and muscle weakness. Children with CP have problems with their
walking ability in terms of walking speed, duration and they fall more often
than typically developing children. Therefore, they experience more problems in
daily live and during playing. Parents and/or children often ask for help for
improving the walking ability in the clinical practice already at an early age.
Children with CP develop their walking ability and walking pattern from the
moment they start with walking till about 8 years old. It is important to guide
the children in improving their walking ability at this early stage.
In clinical practice we often see that the push off is not efficient, which
results in problems in clearance of the foot during walking and causes the many
falling incidents. Also the stride length is short because of the diminished
push off in children with CP. In typically developed walking 50-70% of the push
off is delivered by the strength of the calf muscles. Children with CP have
muscle weakness especially in the more distal muscles of the lower limbs, such
as the calf muscles.
We, therefore, developed a functional power training program, called MegaPower
training, in which they have to use maximal effort of the calf muscles during
functional and known movements such as walking, running and climbing stairs.
The velocity when performing the exercises is the velocity that is common for
the activities they encounter in daily live. The difference between power
training and the more traditional strength training programs are the higher
velocity and the functional multi-joint character of the exercises. The
children are guided carefully during the exercise by the trainer. A story about
super heroes keeps the children motivated to give their best effort during the
training.
In Reade the MegaPower training is already implemented in clinical practice.
From 2011-2012, Reade got financial support from health insurance Agis to
develop and implement the MegaPower training for children from 4-10 years with
spastic CP. Pilot results from the children trained so far at Reade seem very
positive. Before we can implement the MegaPower training at more locations, it
is important to know the real (i.e. evidence-based) effect of the MegaPower
training on the walking ability for children from 4-10 years with spastic CP.

The purpose of this study is to examine whether walking ability and plantar
flexor strength of young children with CP who follow functional power training
improve more compared to usual care.

Procedure
This research protocol has a *double-baseline* research design. The children
that participate are their own controls by measuring their walking ability in
the 14 weeks before the training intervention starts, which is the period of
usual care. Thereafter, they follow the functional power training to be tested
in this study. Fourteen weeks after the end of the training, a follow-up test
is scheduled to assess if the potential improvement is remained.
The 'double baseline' design is chosen instead of a randomized control trial
(RCT) to increase the feasibility of the study and to measure the change within
the individual children in a better way. Parents often prefer the participate
in the intervention group above a control group in a RCT, which makes it hard
for them to participate in a study if they are not certain to get the
intervention. The number of children that are to be included will be more in a
RCT than in a 'double baseline' design, which makes the double-baseline design
more feasible. Graham et al (2012) recently described the disadvantages of a
RCT e.g. the strict inclusion and exclusion criteria of a RCT design make it
difficult for therapists and clinical practitioners to generalize the outcome
of the RCT to their patients in clinical practice. Graham et al (2012)
described the 'double baseline' design as proposed in the present study as an
alternative method in which less patients have to be measured.

The functional power training (MegaPower training) has three elements: 1.
warming-up (10 min), 2. power training (35 min), 3. play (15 min).
Key elements of the power training are; a.) functional loaded, muti-joint
exercises like running and walking with focus on the push-off, b) the velocity
of the movement during the exercises is the same velocity as used in
daily/playing activities, c) 25 till 30 sec maximal effort will be asked of the
children, thereafter they have a resting period of 30 till 50 sec., with 6 till
10 repetitions each exercise, d) Load will increase when possible during the
weeks of the training period, e) training volume exists of load, velocity and
number of repetitions, f) to motivate the children and control the movements
during the exercises they all have a personal coach.

The only risk of participation in this MegaPower will be muscle soreness. The
frequency and severity of muscle soreness will be monitored during the
training.