Does acute passive stretching increase muscle length in children with cerebral palsy?

Effect of arm ergometer versus stabilization exercises on trunk control and pper extremity functions in children with diplegia: a randomized controlled trial

BACKGROUND

One of the most prevalent clinical subtypes of cerebral palsy (CP) is diplegia. Most children with diplegia have weakness in axial muscles and spasticity in extremities which have adverse impacts on trunk control and manual coordination of upper extremities.

AIM

To examine and compare between the effects of arm ergometer and stabilization exercises applied for duration of 12 weeks on upper extremity functioning, trunk control, and hand grip strength (HGS) in children with spastic diplegia.

METHODS

Forty-two children with spastic diplegia aged from 6 to 10 years were randomly assigned to either group A or B, (n = 21 each). Children in group A received a designed arm ergometer exercises for 30 min while those in group B received trunk stabilization exercises for 30 min. As well, children in both groups received 30 min of a designed physical training for 30 min. Treatment was delivered three times a week for 12 weeks in succession. The quality of upper extremity skill test (QUEST), hand held dynamometer (HHD) and Trunk control measuring scale (TCMS) were used to assess upper extremity functions, HGS and trunk control respectively before and after suggested treatment duration.

RESULTS

In terms of all indicators measured at baseline, study groups were comparable (P > 0.05). Significant improvements in all outcome indicators were recorded in within-group comparison (P < 0.05). Further, between groups comparison showed significant higher improvements in upper extremity functions and HGS in favor of group A while trunk control scores showed no significant difference between the two groups (P > 0.05).

CONCLUSION

Arm ergometer exercises have the capability to enhance upper extremity functions, HGS and trunk control. It is therefore beneficial for physical rehabilitation specialists to incorporate the arm ergometer exercises into the intervention plans for children with spastic diplegia.

High Velocity Passive Stretching Mimics Eccentric Exercise in Cerebral Palsy and May Be Used to Increase Spastic Muscle Fascicle Length

Muscle fascicles are shorter and stiffer than normal in spastic Cerebral Palsy (CP). Increasing fascicle length (FL) has been attempted in CP, the outcomes of which have been unsatisfactory. In healthy muscles, FL can be increased using eccentric exercise at high velocities (ECC). Three conditions are possibly met during such ECC: muscle micro-damage, positive fascicle strain, and momentary muscle deactivation during lengthening. Participants with and without CP underwent a single bout of passive stretching at (appropriately) high velocities using isokinetic dynamometry, during which we examined muscle and fascicle behaviour. Vastus lateralis (VL) FL change was measured using ultrasonography and showed positive fascicle strain. Measures of muscle creatine kinase were used to establish whether micro-damage occurred in response to stretching, but the results did not confirm damage in either group. Vastus medialis (VM) and biceps femoris muscle activity were measured using electromyography in those with CP. Results supported momentary spastic muscle deactivation during lengthening: all participants experienced at least one epoch (60 ms) of increased activation followed by activation inhibition/deactivation of the VM during knee flexion. We argue that high-velocity passive stretching in CP provides a movement context which mimics ECC and could be used to increase spastic FL with training.

Immediate effects of a novel hand rehabilitation board on fine motor skills in children with cerebral palsy: A pilot study

BACKGROUND

In children with cerebral palsy (CP), fine motor skills limit forearm supination and active extension of the elbow, wrist, or fingers. Therapeutic interventions focusing on improving the ranges at these joints while facilitating active movements are the key to augmenting fine motor skills.

OBJECTIVE

This pilot study examines if children with CP (with UE involvement) exposed to the Novel Hand Rehabilitation (NHR) Board will demonstrate 1) changes in spasticity and passive ROM of forearm and wrist/finger muscles, and 2) improvement in fine motor abilities.

METHODS

The forearm and wrist/fingers of children with spastic CP (N = 15; M = 7, F = 8) aged 49-72 months (65.33±6.355 months) were positioned on the NHR board till their tolerance limit or a minimum duration of 30 minutes. The outcome measures, i.e., spasticity (Modified Ashworth Scale), passive range of motion (PROM) of wrist and fingers, and fine motor skills (PDMS-2 - Fine motor scale), were recorded.

RESULTS

The spasticity of forearm pronators (0.001) and wrist flexors (0.008) reduced significantly, but not in wrist extensors. Post-intervention improvements in wrist extension (p = 0.005) and ulnar deviation ROM (p = 0.007) were significant. In thumb, changes were non-significant for the CMC flexion, but extension (0.003) and abduction (0.001) as well as MCP extension (0.004) were significant. The post-intervention MCP extension ROM for the 2nd (0.001), 3rd (0.007), and 4th fingers (0.014) were also substantial, but not for PIP and DIP joints. The post-intervention percentage change in the Grasping and Visual-motor integration subtests of PDMS-2 was 11.03% (p = 0.002) and 5.09% (p = 0.001) respectively.

CONCLUSION

The immediate effects on fine motor skills in children with CP after the NHR board application were positive and encouraging. Hence, the NHR board can be recommended as an intervention to improve the fine motor abilities of children with CP.

Constant force muscle stretching induces greater acute deformations and changes in passive mechanical properties compared to constant length stretching

Stretching is applied to lengthen shortened muscles in pathological conditions such as joint contractures. We investigated (i) the acute effects of different types of stretching, i.e. constant length (CL) and constant force (CF) stretching, on acute deformations and changes in passive mechanical properties of medial gastrocnemius muscle (MG) and (ii) the association of acute muscle-tendon deformations or changes in mechanical properties with the impulse or maximal strain of stretching. Forty-eight hindlimbs from 13 male and 12 female Wistar rats (13 weeks old, respectively 424.6 ± 35.5 and 261.8 ± 15.6 g) were divided into six groups (n = 8 each). The MG was initially stretched to a length at which the force was 75%, 95%, or 115% of the force corresponding to estimated maximal dorsiflexion and held at either CF or CL for 30 min. Before and after the stretching protocol, the MG peak force and peak stiffness were assessed by lengthening the passive muscle to the length corresponding to maximal ankle dorsiflexion. Also, the muscle belly length and tendon length were measured. CF stretching affected peak force, peak stiffness, muscle belly length, and tendon length more than CL stretching (p < 0.01). Impulse was associated only with the decrease in peak force, while maximal strain was associated with the decrease in peak force, peak stiffness, and the increase in muscle belly length. We conclude that CF stretching results in greater acute deformations and changes in mechanical properties than CL stretching, which appears to be dependent predominantly on the differences in imposed maximal strain.

Acute passive stretching has no effect on gastrocnemius medialis stiffness in children with unilateral cerebral palsy

PURPOSE

The aim of this study was to investigate the effects of an acute high-intensity, long-duration passive stretching session of the plantar flexor muscles, on maximal dorsiflexion (DF) angle and passive stiffness at both ankle joint and gastrocnemius medialis (GM) muscle levels in children with unilateral cerebral palsy (CP).

METHODS

13 children [mean age: 10 years 6 months, gross motor function classification system (GMFCS): I] with unilateral CP underwent a 5 min passive stretching session at 80% of maximal DF angle. Changes in maximal DF angle, slack angle, passive ankle joint and GM muscle stiffness from PRE- to POST-intervention were determined during passive ankle mobilization performed on a dynamometer coupled with shear wave elastography measurements (i.e., ultrasound) of the GM muscle.

RESULTS

Maximal DF angle and maximal passive torque were increased by 6.3° (P < 0.001; + 50.4%; 95% CI 59.9, 49.9) and 4.2 Nm (P < 0.01; + 38.9%; 95% CI 47.7, 30.1), respectively. Passive ankle joint stiffness remained unchanged (P = 0.9; 0%; 95% CI 10.6, - 10.6). GM muscle shear modulus was unchanged at maximal DF angle (P = 0.1; + 34.5%; 95% CI 44.7, 24.7) and at maximal common torque (P = 0.5; - 4%; 95% CI - 3.7, - 4.3), while it was decreased at maximal common angle (P = 0.021; - 35%; 95% CI - 11.4, - 58.5). GM slack angle was shifted in a more dorsiflexed position (P = 0.02; + 20.3%; 95% CI 22.6, 18).

CONCLUSION

Increased maximal DF angle can be obtained in the paretic leg in children with unilateral CP after an acute bout of stretching using controlled parameters without changes in passive stiffness at joint and GM muscle levels.

CLINICAL TRIAL NUMBER

NCT03714269.

Acute Effects of Static and Proprioceptive Neuromuscular Facilitation Stretching of the Plantar Flexors on Ankle Range of Motion and Muscle-Tendon Behavior in Children with Spastic Cerebral Palsy-A Randomized Clinical Trial

Stretching is considered a clinically effective way to prevent muscle contracture development in children with spastic cerebral palsy (CP). Therefore, in this study, we assessed the effects of a single session of proprioceptive neuromuscular facilitation (PNF) or static stretching (SS) on ankle joint range of motion (RoM) and gastrocnemius muscle-tendon behavior in children with CP. During the SS (n = 8), the ankle joint was held in maximum dorsiflexion (30 s). During the PNF stretching (n = 10), an isometric contraction (3-5 s) was performed, followed by stretching (~25 s). Ten stretches were applied in total. We collected data via dynamometry, 3D motion capture, 2D ultrasound, and electromyography, before and after the stretching sessions. A mixed ANOVA was used for the statistical analysis. Both ankle RoM and maximum dorsiflexion increased over time (F(1,16) = 7.261, p < 0.05, η² = 0.312; and F(1,16) = 4.900, p < 0.05, η² = 0.234, respectively), without any difference between groups. An interaction effect (F(1,12) = 4.768, p = 0.05, η² = 0.284) was observed for muscle-tendon unit elongation (PNF: -8.8%; SS: +14.6%). These findings suggest a positive acute effect of stretching on ankle function. However, SS acutely increased muscle-tendon unit elongation, while this decreased after PNF stretching, indicating different effects on the spastic muscles. Whether PNF stretching has the potential to cause positive alterations in individuals with CP should be elucidated in future studies.

Muscle architecture, growth, and biological Remodelling in cerebral palsy: a narrative review

Cerebral palsy (CP) is caused by a static lesion to the brain occurring in utero or up to the first 2 years of life; it often manifests as musculoskeletal impairments and movement disorders including spasticity and contractures. Variable manifestation of the pathology across individuals, coupled with differing mechanics and treatments, leads to a heterogeneous collection of clinical phenotypes that affect muscles and individuals differently. Growth of muscles in CP deviates from typical development, evident as early as 15 months of age. Muscles in CP may be reduced in volume by as much as 40%, may be shorter in length, present longer tendons, and may have fewer sarcomeres in series that are overstretched compared to typical. Macroscale and functional deficits are likely mediated by dysfunction at the cellular level, which manifests as impaired growth. Within muscle fibres, satellite cells are decreased by as much as 40-70% and the regenerative capacity of remaining satellite cells appears compromised. Impaired muscle regeneration in CP is coupled with extracellular matrix expansion and increased pro-inflammatory gene expression; resultant muscles are smaller, stiffer, and weaker than typical muscle. These differences may contribute to individuals with CP participating in less physical activity, thus decreasing opportunities for mechanical loading, commencing a vicious cycle of muscle disuse and secondary sarcopenia. This narrative review describes the effects of CP on skeletal muscles encompassing substantive changes from whole muscle function to cell-level effects and the effects of common treatments. We discuss growth and mechanics of skeletal muscles in CP and propose areas where future work is needed to understand these interactions, particularly the link between neural insult and cell-level manifestation of CP.

Kinematic and Kinetic Gait Parameters Can Distinguish between Idiopathic and Neurologic Toe-Walking

The differentiation between mild forms of toe-walking (equinus) in cerebral palsy (CP) and idiopathic toe-walking (ITW) is often clinically challenging. This study aims to define kinematic and kinetic parameters using 3D gait analysis to facilitate and secure the diagnosis of “idiopathic toe-walking”. We conducted a retrospective controlled stratified cohort study. 12 toe-walking subjects per group diagnosed as ITW or CP were included and stratified according to age, gender and maximal dorsiflexion in stance. We collected kinematic and kinetic data using a three-dimensional optical motion analysis system with integrated floor force plates. Pairwise comparison between ITW and CP gait data was performed, and discriminant factor analysis was conducted. Both groups were compared with typically developing peers (TD). We found kinematic and kinetic parameters having a high discriminatory power and sensitivity to distinguish between ITW and CP groups (e.g., knee angle at initial contact (91% sensitivity, 73% specificity) and foot progression angle at midstance (82% sensitivity, 73% specificity)). The strength of this study is a high discriminatory power between ITW and CP toe-walking groups. Described kinematic parameters are easy to examine even without high-tech equipment; therefore, it is directly transferable to everyday praxis.

Validity and reliability of a novel 3D ultrasound approach to assess static lengths and the lengthening behavior of the gastrocnemius medialis muscle and the Achilles tendon in vivo

PURPOSE

Human muscle-tendon units (MTUs) are highly plastic and undergo changes in response to specific diseases and disorders. To investigate the pathological changes and the effects of therapeutic treatments, the use of valid and reliable examination methods is of crucial importance. Therefore, in this study, a simple 3D ultrasound approach was developed and evaluated with regard to: (1) its validity in comparison to magnetic resonance imaging (MRI) for the assessment of the gastrocnemius medialis (GM) MTU, muscle belly, and Achilles tendon lengths; and (2) its reliability for static and dynamic length measurements.

METHODS

Sixteen participants were included in the study. To evaluate the validity and reliability of the novel 3D ultrasound approach, two ultrasound measurement sessions and one MRI assessment were performed. By combining 2D ultrasound and 3D motion capture, the tissue lengths were assessed at a fixed ankle joint position and compared to the MRI measurements using Bland-Altman plots. The intra-rater and inter-rater reliability for the static and dynamic length assessments was determined using the coefficient of variation, standard error of measurement (SEM), minimal detectable change (MDC₉₅), and intraclass correlation coefficient (ICC).

RESULTS

The 3D ultrasound approach slightly underestimated the length when compared with MRI by 0.7%, 1.5%, and 1.1% for the GM muscle belly, Achilles tendon, and MTU, respectively. The approach showed excellent intra-rater as well as inter-rater reliability, with high ICC (≥ 0.94), small SEM (≤ 1.3 mm), and good MDC₉₅ (≤ 3.6 mm) values, with even better reliability found for the static length measurements.

CONCLUSION

The proposed 3D ultrasound approach was found to be valid and reliable for the assessment of the GM MTU, muscle belly, and Achilles tendon lengths, as well as the tissue lengthening behavior, confirming its potential as a useful tool for investigating the effects of training interventions or therapeutic treatments (e.g., surgery or conservative treatments such as stretching and orthotics).

LEVEL OF EVIDENCE

Level II.

Effect of Stretching of Spastic Elbow Under Intelligent Control in Chronic Stroke Survivors-A Pilot Study

Objective: To assess the short-term effects of strenuous dynamic stretching of the elbow joint using an intelligent stretching device in chronic spastic stroke survivors.

Methods: The intelligent stretching device was utilized to provide a single session of intensive stretching to the spastic elbow joint in the sagittal plane (i.e., elbow flexion and extension). The stretching was provided to the extreme range, safely, with control of the stretching velocity and torque to increase the joint range of motion (ROM) and reduce spasticity and joint stiffness. Eight chronic stroke survivors (age: 52.6 ± 8.2 years, post-stroke duration: 9.5 ± 3.6 years) completed a single 40-min stretching intervention session. Elbow passive and active ROM, strength, passive stiffness (quantifying the non-reflex component of spasticity), and instrumented tendon reflex test of the biceps tendon (quantifying the reflex component of the spasticity) were measured before and after stretching.

Results: After stretching, there was a significant increase in passive ROM of elbow flexion (p = 0.021, r = 0.59) and extension (p = 0.026, r = 0.59). Also, elbow active ROM and the spastic elbow flexors showed a trend of increase in their strength.

Conclusion: The intelligent stretching had a short-term positive influence on the passive movement ROM. Hence, intelligent stretching can potentially be used to repeatedly and regularly stretch spastic elbow joints, which subsequently helps to reduce upper limb impairments post-stroke.

Interventions and lower-limb macroscopic muscle morphology in children with spastic cerebral palsy: a scoping review

AIM

To identify and map studies that have assessed the effect of interventions on lower-limb macroscopic muscle-tendon morphology in children with spastic cerebral palsy (CP).

METHOD

We conducted a literature search of studies that included pre- and post-treatment measurements of lower-limb macroscopic muscle-tendon morphology in children with spastic CP. Study quality was evaluated and significant intervention effects and effect sizes were extracted.

RESULTS

Twenty-eight articles were identified. They covered seven different interventions including stretching, botulinum neurotoxin A (BoNT-A), strengthening, electrical stimulation, whole-body vibration, balance training, and orthopaedic surgery. Study quality ranged from poor (14 out of 28 studies) to good (2 out of 28). Study samples were small (n=4-32) and studies were variable regarding which muscles and macroscopic morphological parameters were assessed. Inconsistent effects after intervention (thickness and cross-sectional area for strengthening, volume for BoNT-A), no effect (belly length for stretching), and small effect sizes were reported.

INTERPRETATION

Intervention studies reporting macroscopic muscle-tendon remodelling after interventions are limited and heterogeneous, making it difficult to generalize results. Studies that include control groups and standardized assessment protocols are needed to improve study quality and data synthesis. Lack or inconclusive effects at the macroscopic level could indicate that the effects of interventions should also be evaluated at the microscopic level.

WHAT THIS PAPER ADDS

Muscle-targeted interventions to remodel muscle morphology are not well understood. Studies reporting macroscopic muscle remodelling following interventions are limited and heterogeneous. Passive stretching may preserve but does not increase muscle length. The effects of isolated botulinum neurotoxin A injections on muscle volume are inconsistent. Isolated strengthening shows no consistent increase in muscle volume or thickness.

Exercise intervention protocol in children and young adults with cerebral palsy: the effects of strength, flexibility and gait training on physical performance, neuromuscular mechanisms and cardiometabolic risk factors (EXECP)

Background

Individuals with cerebral palsy (CP) have problems in everyday tasks such as walking and climbing stairs due to a combination of neuromuscular impairments such as spasticity, muscle weakness, reduced joint flexibility and poor coordination. Development of evidence-based interventions are in pivotal role in the development of better targeted rehabilitation of CP, and thus in maintaining their motor function and wellbeing. Our aim is to investigate the efficacy of an individually tailored, multifaceted exercise intervention (EXECP) in children and young adults with CP. EXECP is composed of strength, flexibility and gait training. Furthermore, this study aims to verify the short-term retention of the adaptations three months after the end of the EXECP intervention.

Methods

Twenty-four children and young adults with spastic CP will be recruited to participate in a 9-month research project with a 3-month training intervention, consisting of two to three 90-min sessions per week. In each session, strength training for the lower limbs and trunk muscles, flexibility training for the lower limbs and inclined treadmill gait training will be performed. We will evaluate muscle strength, joint flexibility, neuromuscular and cardiometabolic parameters. A nonconcurrent multiple baseline design with two pre-tests and two post-tests all interspaced by three months is used. In addition to the CP participants, 24 typically developing age and sex-matched participants will perform the two pre-tests (i.e. no intervention) to provide normative data.

Discussion

This study has a comprehensive approach examining longitudinal effects of wide variety of variables ranging from physical activity and gross motor function to sensorimotor functions of the brain and neuromuscular and cardiometabolic parameters, providing novel information about the adaptation mechanisms in cerebral palsy. To the best of our knowledge, this is the first intervention study providing supervised combined strength, flexibility and gait training for young individuals with CP.

Trial registration number

ISRCTN69044459, prospectively registered (21/04/2017).

Immediate effects of short period lower limb ergometer exercise in adolescent and young adult patients with cerebral palsy and spastic diplegia

[Purpose] To determine the effects of lower limb ergometer exercise on the spasticity and joint range of motion of the lower extremity and gait function in patients with cerebral palsy and spastic paralysis. [Participants and Methods] This study included 8 participants with cerebral palsy and spastic paralysis (GMFCS levels I to IV) who received care at the outpatient clinic. After a 5-min rest, the lower limb ergometer exercises were performed for 10 min. We measured the participants' arterial blood pressure, pulse rate, passive range of knee joint extension, muscle tone using the Modified Ashworth scale (MAS) and Modified Tardieu scale (MTS), and 10-m walk test (10MWT). Measurements were collected three times (at baseline before exercise, immediately at the end of exercise, and 5 min after exercise during recovery). [Results] The 10-min lower limb ergometer exercise significantly improved the knee joint extension, MAS and MTS scores, and reduced lower extremity spasticity. Furthermore, it significantly increased the range of knee joint extension and decreased the 10MWT score. [Conclusion] The results showed that the 10-minute lower limb ergometer exercise is beneficial in reducing the spasticity of the lower limb muscles and in increasing the range of motion of knee extension in paraplegic patients with cerebral palsy, suggesting that its implementation in young children could prevent spasticity and enhance motor function.

Effects of Self-Massage Using a Foam Roller on Ankle Range of Motion and Gastrocnemius Fascicle Length and Muscle Hardness: A Pilot Study

Context: Several studies have reported that self-massage using a foam roller (FR) increased joint range of motion (ROM) immediately. However, the mechanism of increasing ROM by the FR intervention has not been elucidated. Objective: To clarify the mechanism by investigating properties and morphological changes of muscles targeted by the FR intervention. Design: An interventional study. Setting: An athletic training laboratory. Participants: Ten male college volunteers with no injuries in their lower limbs (mean [SD]: age 23.8 [3.2] y, height 173.2 [4.9] cm, weight 69.5 [8.6] kg). Intervention: The FR intervention on the right plantar flexors for 3 minutes. Main Outcome Measures: Maximum ankle ROM, muscle hardness, and fascicle length of the gastrocnemius muscle at the neutral (0°), maximum dorsiflexion, and maximum plantar flexion positions. All measurements were conducted before (PRE) and after (POST) the FR intervention. Results: Dorsiflexion ROM increased significantly at POST (PRE: 13.6° [8.0°], POST: 16.6° [8.4°]; P < .001), although plantar flexion ROM did not change significantly between PRE and POST (PRE: 40.0° [6.1°], POST: 41.1° [4.9°]). There was no significant difference in muscle hardness and fascicle length between PRE and POST in any of the angles. Conclusions: Dorsiflexion ROM increased significantly by the FR intervention in the present study; however, muscle hardness and fascicle length did not change. FR may affect not only the muscle but also the fascia, tendon, and muscle-tendon unit. The FR protocol of the present study can be applied in clinical situations, because it was found to be effective to increase ROM.

Joint and Muscle Assessments of the Separate Effects of Botulinum NeuroToxin-A and Lower-Leg Casting in Children With Cerebral Palsy

Botulinum NeuroToxin-A (BoNT-A) injections to the medial gastrocnemius (MG) and lower-leg casts are commonly combined to treat ankle equinus in children with spastic cerebral palsy (CP). However, the decomposed treatment effects on muscle or tendon structure, stretch reflexes, and joint are unknown. In this study, BoNT-A injections to the MG and casting of the lower legs were applied separately to gain insight into the working mechanisms of the isolated treatments on joint, muscle, and tendon levels. Thirty-one children with spastic CP (GMFCS I-III, age 7.4 ± 2.6 years) received either two weeks of lower-leg casts or MG BoNT-A injections. During full range of motion slow and fast passive ankle rotations, joint resistance and MG stretch reflexes were measured. MG muscle and tendon lengths were assessed at resting and at maximum dorsiflexion ankle angles using 3D-freehand ultrasound. Treatment effects were compared using non-parametric statistics. Associations between the effects on joint and muscle or tendon levels were performed using Spearman correlation coefficients (p < 0.05). Increased joint resistance, measured during slow ankle rotations, was not significantly reduced after either treatment. Additional joint resistance assessed during fast rotations only reduced in the BoNT-A group (-37.6%, p = 0.013, effect size = 0.47), accompanied by a reduction in MG stretch reflexes (-70.7%, p = 0.003, effect size = 0.56). BoNT-A increased the muscle length measured at the resting ankle angle (6.9%, p = 0.013, effect size = 0.53). Joint angles shifted toward greater dorsiflexion after casting (32.4%, p = 0.004, effect size = 0.56), accompanied by increases in tendon length (5.7%, p = 0.039, effect size = 0.57; r = 0.40). No associations between the changes in muscle or tendon lengths and the changes in the stretch reflexes were found. We conclude that intramuscular BoNT-A injections reduced stretch reflexes in the MG accompanied by an increase in resting muscle belly length, whereas casting resulted in increased dorsiflexion without any changes to the muscle length. This supports the need for further investigation on the effect of the combined treatments and the development of treatments that more effectively lengthen the muscle.

Stretching Interventions in Children With Cerebral Palsy: Why Are They Ineffective in Improving Muscle Function and How Can We Better Their Outcome?

Hyper-resistance at the joint is one of the most common symptoms in children with cerebral palsy (CP). Alterations to the structure and mechanical properties of the musculoskeletal system, such as a decreased muscle length and an increased joint stiffness are typically managed conservatively, by means of physiotherapy involving stretching exercises. However, the effectiveness of stretching-based interventions for improving function is poor. This may be due to the behavior of a spastic muscle during stretch, which is poorly understood. The main aim of this paper is to provide a mechanistic explanation as to why the effectiveness of stretching is limited in children with CP and consider clinically relevant means by which this shortcoming can be tackled. To do this, we review the current literature regarding muscle and tendon plasticity in response to stretching in children with CP. First, we discuss how muscle and tendon interact based on their morphology and mechanical properties to provide a certain range of motion at the joint. We then consider the effect of traditional stretching exercises on these muscle and tendon properties. Finally, we examine possible strategies to increase the effectiveness of stretching therapies and we highlight areas of further research that have the potential to improve the outcome of non-invasive interventions in children with cerebral palsy.

Stretching and Progressive Resistance Exercise in Children With Cerebral Palsy: A Randomized Controlled Trial

PURPOSE

To evaluate the effect of stretching and progressive resistance exercise on range of motion and muscle strength in children with cerebral palsy.

METHODS

Thirty-seven children with spastic bilateral cerebral palsy and Gross Motor Function Classification System levels I to III were randomized to an intervention and a comparison group. The intervention included stretching of hamstrings and progressive resistance exercise, targeting the lower extremities for 16 weeks, followed by a 16-week maintenance program. Passive and active popliteal angle and muscle strength were evaluated at 0, 16, and 32 weeks.

RESULTS

After 16 weeks nonsignificant improvements were found in passive, active popliteal angle and quadriceps and hamstrings strength.

CONCLUSION

A 16-week stretching and progressive resistance exercise program followed by a 16-week maintenance program showed nonsignificant improvements in passive, active popliteal angle and muscle strength for the intervention group.

Effect of a Combined Stretching and Strength Training Program on Gait Function in Children with Cerebral Palsy, GMFCS Level I & II: A Randomized Controlled Trial

Background and objectives: Ambulant children with cerebral palsy (CP) often develop impaired gait, and reduced active knee extension is often a part of the problem. This study aimed to evaluate the effect of a combined intervention program including stretching and progressive resistance exercise (PRE) targeting active knee extension on gait function, in children with spastic CP. Materials and methods: Thirty-seven children (21 boys, 16 girls, mean age 10.2 (±2.3) years), classified by Gross Motor Function Classification System I-III, were randomized to an intervention (n = 17) and a comparison group (n = 20). The intervention group received a 16-week combined exercise program (3 sessions per week) including stretching of hamstrings and PRE targeting the lower extremities, followed by a 16-week maintenance program (1 session per week). The comparison group received care as usual. Gait function was evaluated by three-dimensional gait analysis (3DGA); knee, hip and pelvic kinematics in the sagittal plane, step length and speed, Gait Deviation Index (GDI), and Six-Minute Walk test (6MWT) at 0, 16, and 32 weeks. Results: There were no statistically significant differences between the intervention group and the comparison group for any of the gait parameters measured at 16 and 32 weeks. There was a significant increase in gait distance measured by 6MWT within both groups; however, no differences between the groups were found. Conclusion: A 16-week combined stretching and PRE program followed by a 16-week maintenance program did not improve gait function in ambulant children with CP.

Effects of backward-downhill treadmill training versus manual static plantarflexor stretching on muscle-joint pathology and function in children with spastic Cerebral Palsy

BACKGROUND

Patients with spastic Cerebral Palsy are prone to equinus deformities, likely affected by short and inextensible plantarflexor muscles. Manual stretching is a popular treatment but its effectiveness concerning joint mobility, muscle-tendon morphometrics and walking function is debated. Eccentric exercise by backward-downhill treadmill training could be a therapeutic alternative for ambulatory patients improving gait and muscle function.

RESEARCH QUESTION

What are the effects of eccentric training by backward-downhill treadmill training and plantarflexor stretching concerning gait and muscle function in patients with spastic Cerebral Palsy?

METHODS

10 independent ambulators with spastic Cerebral Palsy (12 [SD 4] years old, 2 uni- and 8 bilaterally affected) participated in a randomized crossover-study. One group started with manual static stretching, the other one with backward-downhill treadmill training. Each treatment period lasted 9 weeks (3 sessions per week). Pre and post treatments, 3D gait was assessed during comfortable and during fastest possible walking. Ultrasonography and dynamometry were used to test plantarflexor strength, passive joint flexibility, as well as gastrocnemius morphometrics, stiffness and strain on muscle-tendon and joint level.

RESULTS

When comparing both treatments, backward-downhill treadmill training lead to larger single stance dorsiflexion at comfortable walking speed (+2.9°, P = 0.041) and faster maximally achievable walking velocities ( + 0.10 m/s, P = 0.017). Stretching reduced knee flexion in swing, particularly at faster walking velocities (-5.4°, P = 0.003). Strength, ankle joint flexibility, as well as stiffness on muscle-tendon and joint level were not altered, despite similar increases in passive muscle and fascicle strain with both treatments (P ≤ 0.023).

SIGNIFICANCE

Backward-downhill treadmill training can be an effective gait treatment, probably improving coordination or reducing dynamic stretch sensitivity. More intense BDTT might be necessary to further alter muscle-tendon properties. Manual static plantarflexor stretching may not be optimal in Cerebral Palsy patients with high ambulatory status.

Stretch Could Reduce Hamstring Injury Risk During Sprinting by Right Shifting the Length-Torque Curve

Ruan, M, Li, L, Chen, C, and Wu, X. Stretch could reduce hamstring injury risk during sprinting by right shifting the length-torque curve. J Strength Cond Res 32(8): 2190-2198, 2018-It was hypothesized that static stretch would shift the length-torque curve to the right, which may reduce the risk of muscle strain injuries. The purpose of this study was to evaluate the acute effects of static stretching of hamstring (SSH) on the risk of hamstring injury during sprinting indicated by the shift of the length-torque relationship. Twelve female college athletes (age: 20.8 ± 0.7 years; height: 1.61 ± 0.05 m; body mass: 54.25 ± 4.22 kg) participated in this study. Subjects performed overground sprinting under 2 conditions: after warm-up with 4 × 30 seconds SSH or after warm-up without SSH. Three-dimensional kinematic and kinetic data and electromyography of biceps femoris long head (BFlh), rectus femoris, and vastus medialis were collected during testing. The maximum length of BFlh during late swing phase increased after SSH with large effect size and close to statistically significant (p = 0.05, d = 1.22), but the knee flexion torque at the peak length did not change significantly. Static stretching of hamstring significantly reduced peak values of both horizontal (d = 1.46) and vertical (d = 1.79) ground reaction forces, and BFlh's activation level during the preactivation (late swing) phase (p = 0.05, d = 2.16). The results indicated that the length of BFlh-knee torque relationship and the length of BFlh-hip torque relationships during the late swing phase and initial stance phase were shifted to the right after SSH, which may reduce risk of hamstring strain injuries. We suggest that preactivity static stretching should not be simply removed and participators should give priority to stretch muscles that are vulnerable to strain injuries.

What's New in the Management of Foot Deformities in Children With Cerebral Palsy

BACKGROUND

Foot deformities have been frequently reported in cerebral palsy (CP), and numerous diagnostic modalities and treatment options have recently been developed to achieve a better level of management for children with CP.

METHODS

A thorough search of the English literature, published between January 2013 and March 2016, was performed. A summary of the new findings that had not previously described was reported. The review included recent advances regarding clinical and gait evaluation, orthotic management, botulinum toxin A treatment, and surgical correction.

RESULTS

The review summarized new findings reported in 46 articles and abstracts that were published between January 2013 and March 2016. Older articles were included and cited when an original description was mentioned, or when a change or development of some findings was discussed.

CONCLUSIONS

Foot deformity forms an essential part of evaluating children with CP. Dramatic advances have been achieved in gait assessment, conservative management, and surgical correction. Promising results have been reported with the goal to reach a higher level of orthopaedic care and optimize the functional potentials for children with CP.

LEVEL OF EVIDENCE

Level IV-literature review.

Information from dynamic length changes improves reliability of static ultrasound fascicle length measurements

Purpose

Various strategies for improving reliability of fascicle identification on ultrasound images are used in practice, yet these strategies are untested for effectiveness. Studies suggest that the largest part of differences between fascicle lengths on one image are attributed to the error on the initial image. In this study, we compared reliability results between different strategies.

Methods

Static single-image recordings and image sequence recordings during passive ankle rotations of the medial gastrocnemius were collected. Images were tracked by three different raters. We compared results from uninformed fascicle identification (UFI) and results with information from dynamic length changes, or data-informed tracking (DIT). A second test compared tracking of image sequences of either fascicle shortening (initial-long condition) or fascicle lengthening (initial-short condition).

Results

Intra-class correlations (ICC) were higher for the DIT compared to the UFI, yet yielded similar standard error of measurement (SEM) values. Between the initial-long and initial-short conditions, similar ICC values, coefficients of multiple determination, mean squared errors, offset-corrected mean squared errors and fascicle length change values were found for the DIT, yet with higher SEM values and greater absolute fascicle length differences between raters on the first image in the initial-long condition and on the final image in the initial-short condition.

Conclusions

DIT improves reliability of fascicle length measurements, without lower SEM values. Fascicle length on the initial image has no effect on subsequent tracking results. Fascicles on ultrasound images should be identified by a single rater and care should be taken when comparing absolute fascicle lengths between studies.

Relationship between muscle-tendon length, range of motion, and resistance to passive movement in children with normal and increased tone

[Purpose] The aim of this study was to quantify the resistance to passive movement by measuring changes in muscle-tendon length and joint range of motion (ROM), before and after applying a standardized 5-kilogram tension force, and to correlate and compare these changes to muscle tone. [Subjects and Methods] Children with cerebral palsy (n=29) and typically developed children (n=12) participated in this observational study. The modified Ashworth scale (MAS) was used to assess tone in the right plantarflexor muscle. An ultrasound-imaging device was used to measure Δmuscle-tendon length in the right medial gastrocnemius muscle, and a goniometer was used to measure right ankle ΔROM. [Results] Compared with the MAS, the results showed that ΔROM had the highest construct validity (convergent and discriminant) followed by Δmuscle-tendon unit length. Therefore, these parameters may be better alternatives to the MAS for the quantitative assessment of resistance to passive movement in patients with increased tone. [Conclusion] This study demonstrated that measuring the change in the passive properties of the muscle-tendon unit, as well as the corresponding change in ROM, might provide better options for assessing resistance to passive movement or muscle tone.

Real-time feedback of dynamic foot pressure index for gait training of toe-walking children with spastic diplegia

PURPOSE

The aim of this study was to determine whether and how real-time feedback of dynamic foot pressure index (DFPI) could be used to correct toe-walking gait in spastic diplegic children with dynamic equinus.

METHODS

Thirteen spastic diplegic children with dynamic equinus were asked to wear a monitoring device to record their ambulation during daily gait, conventional training gait, and feedback training gait. Parameters based on their DFPI and stride duration were compared among the three test conditions.

RESULTS

The results with feedback training were significantly better for all DFPI parameters in comparison to patients' daily gait and showed significant improvements in DFPI for toe-walking gait and percentage of normal gait in comparison to conventional training methods. Moreover, stride duration under two training gaits was longer than patient's daily gait, but there was no significant difference between the two training gaits.

CONCLUSIONS

Although the stride duration for the two training gaits was similar, gait training with real-time feedback of DFPI did produce noticeably superior results by increasing heel-loading impulse of toe-walking gait and percentage of normal gait in comparison to convention training methods. However, its effectiveness was still impacted by the motion limitations of diplegic children. Implications for Rehabilitation The DFPI-based gait training feedback system introduced in this study was shown to be more effective at toe-walking gait rehabilitation training over conventional training methods. The feedback system accomplished superior improvement in correcting toe-walking gait, but its effectiveness in an increasing heel-loading impulse in normal gait was still limited by the motion limitations of diplegic children. Stride duration of normal gait and toe-walking gait was similar under conventional and feedback gait training.

Home-Based Versus Laboratory-Based Robotic Ankle Training for Children With Cerebral Palsy: A Pilot Randomized Comparative Trial

OBJECTIVE

To examine the outcomes of home-based robot-guided therapy and compare it to laboratory-based robot-guided therapy for the treatment of impaired ankles in children with cerebral palsy.

DESIGN

A randomized comparative trial design comparing a home-based training group and a laboratory-based training group.

SETTING

Home versus laboratory within a research hospital.

PARTICIPANTS

Children (N=41) with cerebral palsy who were at Gross Motor Function Classification System level I, II, or III were randomly assigned to 2 groups. Children in home-based and laboratory-based groups were 8.7±2.8 (n=23) and 10.7±6.0 (n=18) years old, respectively.

INTERVENTIONS

Six-week combined passive stretching and active movement intervention of impaired ankle in a laboratory or home environment using a portable rehabilitation robot.

MAIN OUTCOME MEASURES

Active dorsiflexion range of motion (as the primary outcome), mobility (6-minute walk test and timed Up and Go test), balance (Pediatric Balance Scale), Selective Motor Control Assessment of the Lower Extremity, Modified Ashworth Scale (MAS) for spasticity, passive range of motion (PROM), strength, and joint stiffness.

RESULTS

Significant improvements were found for the home-based group in all biomechanical outcome measures except for PROM and all clinical outcome measures except the MAS. The laboratory-based group also showed significant improvements in all the biomechanical outcome measures and all clinical outcome measures except the MAS. There were no significant differences in the outcome measures between the 2 groups.

CONCLUSIONS

These findings suggest that the translation of repetitive, goal-directed, biofeedback training through motivating games from the laboratory to the home environment is feasible. The benefits of home-based robot-guided therapy were similar to those of laboratory-based robot-guided therapy.

Does long-term passive stretching alter muscle-tendon unit mechanics in children with spastic cerebral palsy?

BACKGROUND

Cerebral palsy causes motor impairments during development and many children may experience excessive neural and mechanical muscle stiffness. The clinical assumption is that excessive stiffness is thought to be one of the main reasons for functional impairments in cerebral palsy. As such, passive stretching is widely used to reduce stiffness, with a view to improving function. However, current research evidence on passive stretching in cerebral palsy is not adequate to support or refute the effectiveness of stretching as a management strategy to reduce stiffness and/or improve function. The purpose was to identify the effect of six weeks passive ankle stretching on muscle-tendon unit parameters in children with spastic cerebral palsy.

METHODS

Thirteen children (8-14 y) with quadriplegic/diplegic cerebral palsy were randomly assigned to either an experimental group (n=7) or a control group (n=6). The experimental group underwent an additional six weeks of passive ankle dorsiflexion stretching for 15 min (per leg), four days per week, whilst the control group continued with their normal routine, which was similar for the two groups. Measures of muscle and tendon stiffness, strain and resting length were acquired pre- and post-intervention.

FINDINGS

The experimental group demonstrated a 3° increase in maximum ankle dorsiflexion. This was accompanied by a 13% reduction in triceps surae muscle stiffness, with no change in tendon stiffness. Additionally, there was an increase in fascicle strain with no changes in resting length, suggesting muscle stiffness reductions were a result of alterations in intra/extra-muscular connective tissue.

INTERPRETATION

The results demonstrate that stretching can reduce muscle stiffness by altering fascicle strain but not resting fascicle length.

Effects of ankle-foot braces on medial gastrocnemius morphometrics and gait in children with cerebral palsy

PURPOSE

In children with cerebral palsy (CP), braces are used to counteract progressive joint and muscle contracture and improve function. We examined the effects of positional ankle-foot braces on contracture of the medial gastrocnemius (MG) and gait in children with CP while referencing to typically developing children.

METHODS

Seventeen independently ambulant children with CP and calf muscle contracture (age 10.4 ± 3.0y) and 17 untreated typically developing peers (age 9.5 ± 2.6y) participated. Children with CP were analysed before and 16 ± 4 weeks after ankle-foot bracing. MG muscle belly length and thickness, tendon and fascicle length, as well as their extensibility were captured by 2D ultrasound and 3D motion capturing during passive, manually applied stretches. In addition, 3D gait analysis was conducted.

RESULTS

Prior to bracing, the MG muscle-tendon unit in children with CP was 22 % less extensible. At matched amounts of muscle-tendon unit stretch, the muscle belly and fascicles in CP were 7 % and 14 % shorter while the tendon was 11 % longer. Spastic fascicles displayed 32 % less extensibility than controls. Brace wear increased passive dorsiflexion primarily with the knees flexed. During gait, children walked faster and foot lift in swing improved. MG muscle belly and tendon length showed little change, but fascicles further shortened (-11 %) and muscle thickness (-8 %) decreased.

CONCLUSIONS

Use of ankle-foot braces improves function but may lead to a loss of sarcomeres in series, which could explain the shortened fascicles. To potentially induce gastrocnemius muscle growth, braces may also need to extend the knee or complementary training may be necessary to offset the immobilizing effects of braces.

Measuring the Pain Area: An Intra- and Inter-Rater Reliability Study Using Image Analysis Software

Pain drawings have frequently been used for clinical information and research. The aim of this study was to investigate intra- and inter-rater reliability of area measurements performed on pain drawings. Our secondary objective was to verify the reliability when using computers with different screen sizes, both with and without mouse hardware. Pain drawings were completed by patients with chronic neck pain or neck-shoulder-arm pain. Four independent examiners participated in the study. Examiners A and B used the same computer with a 16-inch screen and wired mouse hardware. Examiner C used a notebook with a 16-inch screen and no mouse hardware, and Examiner D used a computer with an 11.6-inch screen and a wireless mouse. Image measurements were obtained using GIMP and NIH ImageJ computer programs. The length of all the images was measured using GIMP software to a set scale in ImageJ. Thus, each marked area was encircled and the total surface area (cm(2) ) was calculated for each pain drawing measurement. A total of 117 areas were identified and 52 pain drawings were analyzed. The intrarater reliability between all examiners was high (ICC = 0.989). The inter-rater reliability was also high. No significant differences were observed when using different screen sizes or when using or not using the mouse hardware. This suggests that the precision of these measurements is acceptable for the use of this method as a measurement tool in clinical practice and research.