Stretching and Strength Training for Improved Gait Function in Children With Spastic Cerebral Palsy

The purpose of this randomized and controlled intervention study is to explore the effect of a physiotherapy intervention targeting contract and spastic hamstring muscles in children having bilateral spastic cerebral palsy (CP), GMFCS I-III: A stretching routine targeting hamstrings (and psoas if short), and a progressive strengthening program on the muscles extending then lower extremities (quadriceps, gluteus maximus and triceps surae)

Study hypothesis: Stretching of hamstrings and strength training of the extending muscles in the lower extremities in children with bilateral spastic cerebral palsy will increase popliteal angle, active knee extension, and gait function.

The key intervention: 16 weeks with three treatment sessions each week. Minimum pause between two treatment sessions is one day. Week 1 and 2: To assure the correct dosage in each exercise and a satisfactory education of the session done at home, all three sessions will be implemented with the physiotherapist the first two weeks. From week 3: Two treatment/training sessions with the physiotherapist and one shorter training session at home.

Maintenance intervention: From week 17 to week nr 32.; One session pr. week will be performed at home, together with an assistant in school or with the physiotherapist. How this is accomplished will depend on what is feasible for the child and the parents.

The physiotherapy sessions: 2 sessions pr week. 5-10 min. warm up on a treadmill or a bike. A stretching exercise on the hamstrings (and psoas if shortened; ≤ 5º hip extension) and 3 strength exercises targeting the muscles extending the hip, knee and ankle.

The intervention is expected to last 30 min. and it is an extra session on top of the usual physiotherapy intervention given the child.

Home session: One session pr. week, lasting 10-15 min. No need of warm up. The session is contending one stretching exercise on hamstrings and one strength exercise. The exercises will be modified individually so the children are able to do them at home.

Exercise registration: The physiotherapist will be asked to register the sessions performed each week. The reason why a session is not performed should be registered (a scheme is attached).

The stretching (exercise schema p.3): Two stretching exercises will be performed on hamstrings, and if the psoas muscle is short (≤ 5º hip extension) there should also be a stretch performed on psoas. The stretching shall not be painful for the child.

The strength training exercises (exercises schema p.4 and 5): The strength training will be performed following the principles of "Progressive Resistance Exercise" (PRE) and the recommendations from The National Strength and Conditioning Association (NSCA) concerning strength training for children12. The recommended weight resistance for children who are familiar with strength training are 60-80% of 1RM (Repetition Maximum = maximum weight when lifting one repetition), 2- 3 sets and 8-12 repetitions, 2 -3 times per week. Verscuhen and collegues13 recommendations concerning a strength training protocol for children with CP are taken into account: not only multi -joint exercises, but also singe - joint exercises, extended rest between exercises (min 2-3 minute), minimum 12 weeks of intervention and the children should be over 7 years of age. The standing exercises shall be performed with a back pack (everyone in the intervention group will get one) which is possible to load with weights/bottles of water.

Customization of weight resistance

Children having CP are likely to be diverse and according to physical conditions and because of that 1 Repetition Maximum (1RM) will most likely be to difficult to perform. For estimation of the optimal and individualized resistance throughout the period of intervention a modified test shall be performed.

The test will be performed after the child have understood and completed the exercises correct, during the first two weeks. Until that the physiotherapist will do a mapping of the child's strength skills in order to recognize the wright amount of weight for the child for 12 repetitions and 2 series. As of week 3 there are 3 series per exercises. Recommendations from the study done by Sholtes et all14 are used for guiding of optimal weight dosage. In this study they found that for 8 RM in a sit- to stand exercise, for those having CP GMFCS I-III the weight should be 35%, 30% and 25% respectively of body weight.

Performance of the RM test: Starting out with 3 repetitions without any resistance throughout the range of moment. Every repetition shall be performed as correct and controlled as passible throughout the range of moment and the speed is 2-3 sec. per extension/flexion movement. If one repetition is carried out incorrectly with respect to speed and movement quality it shall not be counted.

The RM test shall be conducted the first time in the end of the second week (12 RM x 3 series), then next time in week 5. (10 RM x 3 series), week 8. (8 RM x 3 series), and finally in week 14. (8 RM x 3 series). When the child can do more than 12, 10 or 8 repetitions respectively, there shall be added more weight. The weight changes shall be registered in a registration form.

RM test shall be performed in exercise nr 1),2) and 3). Exercise nr 4) is mostly an awareness exercise where the focus is on quality and the ability to activate m.vastus medialis by doing a max extension in the knee in a prone position.

Eligibility Criteria:
Inclusion Criteria:

* Spastic bilateral cerebral palsy GMFCS I-III (ability to walk without aid for 10 m)
* Popliteal angle ≥ 35°

Exclusion Criteria:

* No surgical lengthening on hamstrings or bilateral triceps surae
* No surgical intervention on the lower extremities one year prior to inclusion
* No surgical intervention on the lower extremities one year prior to inclusion
* Surgical operations which is planned for the upcoming year
* No botulinum injections in hamstrings or other muscles in the lower extremities the last 6 month prior to inclusion.
* External rotation in the hips ≤ 5°
* \< 90° passive ankle dorsal flexion in the ankles on a extended knee
* Reduced ability to cooperate or receive instructions