Is muscle stiffness a determinant for range of motion in the leg muscles?

Previous training studies with comprehensive stretching durations have reported that an increase in range of motion (ROM) can be related to decreases in muscle stiffness. Therefore, the purpose of this study was to analyze the association between the passive muscle stiffness of three muscle groups (triceps surae, quadriceps, hamstrings) to the respective joint ROM. Thirty-six healthy male soccer players volunteered in this study. After a standardized warm-up, the muscle stiffness was tested via shear wave elastography in six muscles (gastrocnemius medialis and lateralis, rectus femoris, semitendinosus, semimembranosus, and biceps femoris long head). The hip extension, hip flexion, and ankle dorsiflexion ROM were also assessed with a modified Thomas test, a sit and reach test, and a standing wall push test, respectively. We found significant moderate to large correlations between hip flexion ROM and muscle stiffness for the semimembranosus (rP = -0.43; P = 0.01), biceps femoris long head (rP = -0.45; P = 0.01), and overall hamstring stiffness (rP = -0.50; P < 0.01). No significant correlations were found for triceps surae (rP = -0.12; P = 0.51 to 0.67) and rectus femoris muscle stiffness (rP = 0.25; P = 0.14) with ankle dorsiflexion and hip extension ROM, respectively. We conclude that muscle stiffness is an important contributor to hip flexion ROM, but less important for hip extension or ankle joint ROM. Additional contributors to ROM might be tendon stiffness or stretch/pain tolerance.

Remote effects of a 7-week combined stretching and foam rolling training intervention of the plantar foot sole on the function and structure of the triceps surae.

It is known that a single bout of foam rolling (FR) or stretching can induce changes in range of motion (ROM) and performance in non-directly adjoining areas of the dorsal chain (i.e., remote effects). However, to date, it is not known if such effects exist following long-term interventions. Thus, the purpose of this study was to investigate the remote effects of a 7-week combined stretching and FR training intervention of the plantar foot sole. Thirty-eight recreational athletes were randomly assigned to either an intervention (n = 20) or control (n = 18) group. The intervention group performed stretching and FR exercises of the plantar foot sole for 7 weeks. Before and after the intervention, the dorsiflexion ankle ROM, passive resistive torque at maximum angle (PRTmax) and at a fixed angle, as well as maximum voluntary isometric contraction (MVIC) torque, were measured with a dynamometer. Gastrocnemius medialis and lateralis stiffness was assessed with shear wave elastography. The results showed no interaction effect for any of the parameters. There was a time effect indicating an increase in MVIC and PRTmax, which was more pronounced in the intervention group (+ 7.4 (95% CI 2.5-12.4), + 4.5 (95% CI - 0.2-9.2)) than the control group (+ 3.6 (95% CI - 1.4-8.6), + 4.0 (95% CI - 2.2 to 10.2)). The results indicate no or minor remote effects of combined stretching and FR of the foot sole in the ankle joint. Potential non-significant changes in ROM were accompanied with an increase in stretch tolerance, but not with changes in muscle structure.

The Acute Effects of Pectoralis Major Foam Ball Rolling on Shoulder Extension Range of Motion, Isometric Contraction Torque, and Muscle Stiffness.

Although it is well known that foam rolling (FR) of the lower extremities can increase the range of motion (ROM) of a joint while likely having no detrimental effect on muscle performance, to date, this is not clear if this is the case for the upper body. Therefore, the purpose of this study was to analyze the effects of a 2-min FR intervention of the pectoralis major (PMa) muscle on muscle stiffness of the PMa, shoulder extension ROM, and maximal voluntary isometric contraction (MVIC) peak torque. Thirty-eight (n = 15 females) healthy, physically active participants were randomly assigned to either an intervention (n = 18) or a control group (n = 20). The intervention group performed a 2-min foam ball rolling (FBR) intervention of the PMa muscle (FB-PMa-rolling), while the control group rested for 2 min. Before and after the intervention, muscle stiffness of the PMa was measured with shear wave elastography, while shoulder extension ROM was recorded with a 3D-motion capture system, and shoulder flexion MVIC peak torque was measured with a force sensor. MVIC peak torque decreased in both groups (time effect: p = 0.01; η2 = 0.16), without any difference between groups (interaction effect: p = 0.49, η2 = 0.013). ROM (p = 0.24; η2 = 0.04) and muscle stiffness (FB-PMa-rolling p = 0.86; Z = -0.38; control group p = 0.7, Z = -0.17) did not change due to the intervention. The lack of changes in ROM and muscle stiffness following the FBR intervention might be explained by the small area of applied pressure with the FBR on the PMa muscle. Moreover, the decrease in MVIC peak torque is likely more related to the uncommon test situation of the upper limbs, rather than the FBR intervention itself.

The Relationship Between Lower Limb Passive Muscle and Tendon Compression Stiffness and Oxygen Cost During Running.

Studies have reported that a stiff triceps surae muscle and tendon-aponeurosis and also a more compliant quadriceps muscle and tendon-aponeurosis, are related to lower oxygen cost during running. However, to date, no study has investigated in a single experiment how oxygen cost during running is related to the stiffness of the free tendons (Achilles tendon, patellar tendon) and all the superficial muscles of two major muscle groups for running (i.e., quadriceps, triceps surae). Thus, 17 male trained runners/triathletes participated in this study and visited the laboratory on three occasions. On the first day, the participants were familiarized with the tests. On the second day, the passive compression stiffness of the triceps surae muscle (i.e., gastrocnemii), Achilles tendon, quadriceps muscle (i.e., vastii, rectus femoris), and patellar tendon was non-invasively measured using a digital palpation device (MyotonPRO). In addition, an incremental test was applied to test the VO2max of the participants. Thereafter, in the third visit, after at least 48-h of rest, participants performed a 15-min run on the treadmill with a speed reflecting a velocity of 70% VO2max, to assess oxygen costs during running. The Spearman correlation showed a significant negative correlation between passive Achilles tendon compression stiffness and running oxygen consumption, with a large effect size (rρ = -0.52; CI (95%) -0.81 to -0.33; P = 0.03). Moreover, no further significant relationship between oxygen cost during running and the passive compression stiffness of the quadriceps muscle and patellar tendon, as well as the triceps surae muscle, was detected. The significant correlation indicates that a stiffer passive Achilles tendon can lead to a lower oxygen cost during running. Future studies will have to test the causality of this relationship with training methods such as strength training that are able to increase the Achilles tendon stiffness.

Mental calculation increases physiological postural tremor, but does not influence physiological goal-directed kinetic tremor.

PURPOSE: During a cognitive effort, an increase in cortical electrical activity, functional alterations in the anterior cingulate cortex, and modifications in cortical inputs to the active motor units have been reported. In light of this, an increase in tremor could be anticipated as result of a mental task. In the present work, we tested this hypothesis. METHODS: In 25 individuals, tremor was measured with a three-axial accelerometer during 300 s of postural and goal-directed tasks performed simultaneously to mental calculation, or during control (same tasks without mental calculation). Hand and finger dexterity were also evaluated. Electromyographic (EMG) recordings from the extensor digitorum communis were collected during the postural task. RESULTS: Hand and finger dexterity was negatively affected by the mental task (p = .003 and p = .00005 respectively). During mental calculation, muscle tremor increased in the hand postural (+ 29%, p = .00005) but not in the goal-directed task (- 1.5%, p > .05). The amplitude of the main frequency peak also increased exclusively in the hand postural task (p = .028), whilst no shift in the position of the main frequency peak was observed. EMG was not affected. CONCLUSION: These results support the position of the contribution of a central component in the origin of physiological hand postural tremor. It is suggested that the different effect of mental calculation on hand postural and goal-directed tasks can be attributed to the different origins and characteristics of hand postural and goal-directed physiological tremor.

A comparison of a single bout of stretching or foam rolling on range of motion in healthy adults.

PURPOSE: Stretching and foam rolling are common warm-up exercises and can acutely increase the range of motion (ROM) of a joint. However, possible differences in the magnitude of change on ROM between these two interventions on the immediate and prolonged effects (e.g., 10 min after the intervention) are not yet well understood. Thus, the purpose of this review was to compare the immediate and prolonged effects of a single bout of foam rolling with a single bout of stretching on ROM in healthy participants. METHODS: In total, 20 studies with overall 38 effect sizes were found to be eligible for a meta-analysis. For the main analysis, subgroup analysis, we applied a random-effect meta-analysis, mixed-effect model, respectively. The subgroup analyses included age groups, sex, and activity levels of the participants, as well as the tested muscles, the duration of the application, and the study design. RESULTS: Meta-analyses revealed no significant differences between a single stretching and foam rolling exercise immediately after the interventions (ES = 0.079; P = 0.39) nor a difference 10 min (ES = - 0.051; P = 0.65), 15 min (ES = - 0.011; P = 0.93), and 20 min (ES = - 0.161; P = 0.275) post-intervention. Moreover, subgroup analyses revealed no other significant differences between the acute effects of stretching and foam rolling (P > 0.05). CONCLUSION: If the goal is to increase the ROM acutely, both interventions can be considered as equally effective. Likely, similar mechanisms are responsible for the acute and prolonged ROM increases such as increased stretch tolerance or increased soft-tissue compliance.

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.

Spike Arm Swing Techniques of Olympics Male and Female Elite Volleyball Players (1984-2021).

In the last decades, indoor volleyball has experienced significant rule changes and a high player specialization in both sexes. Different spike attack arm swing techniques have developed which might affect performance and risk of injury. While a variety of arm swing techniques was already shown in world class beach volleyball players, it is unclear if this is also true for world class indoor volleyball. Therefore, the purpose of this study was to assess the spike attack arm swing techniques of Olympic volleyball winners and finalists (1984-2021) and to investigate possible differences between sex, playing position, scoring system, and compared to beach volleyball. Eighty-two male (M) and 85 female (F) players were assessed from video recordings from ten competitions. Five different arm swing techniques in the cocking phase (Straight, Bow-and-arrow high, Bow-and-arrow low, Snap, Circular) were classified by two experts. The most frequent technique for both sexes was the Circular (M = 40.2%; F = 38.8%), followed by Snap (M = 28.0%; F = 23.5%), Bow-and-arrow low (M = 20.7%; F = 21.2%), Bow-and-arrow high (M = 7.3% F = 11.8%), and Straight (M = 3.7%; F = 4.7%). Bow-and-arrow high and Straight techniques were significantly less used than other techniques in both sexes. There were no significant differences (p > 0.05) in arm swing techniques between sexes, playing positions, and scoring system but significant differences (p < 0.001) to beach volleyball. Although most volleyball textbooks only describe the Bow-and-arrow techniques, most of the world class indoor volleyball players used Circular and Snap arm swing techniques. Reasons for that could be the implicit knowledge of players (and coaches) regarding increased performance (ball speed) and injury prevention. Based on these results we suggest to critically revise arm swing technique training especially for young players and players with shoulder problems.

Comparison of A Single Vibration Foam Rolling and Static Stretching Exercise on the Muscle Function and Mechanical Properties of the Hamstring Muscles.

Knee extension and hip flexion range of motion (ROM) and functional performance of the hamstrings are of great importance in many sports. The aim of this study was to investigate if static stretching (SS) or vibration foam rolling (VFR) induce greater changes in ROM, functional performance, and stiffness of the hamstring muscles. Twenty-five male volunteers were tested on two appointments and were randomly assigned either to a 2 min bout of SS or VFR. ROM, counter movement jump (CMJ) height, maximum voluntary isometric contraction (MVIC) peak torque, passive resistive torque (PRT), and shear modulus of semitendinosus (ST), semimembranosus (SM), and biceps femoris (BFlh), were assessed before and after the intervention. In both groups ROM increased (SS = 7.7%, P < 0.01; VFR = 8.8%, P < 0.01). The MVIC values decreased after SS (-5.1%, P < 0.01) only. Shear modulus of the ST changed for -6.7% in both groups (VFR: P < 0.01; SS: P < 0.01). Shear modulus decreased in SM after VFR (-6.5%; P = 0.03) and no changes were observed in the BFlh in any group (VFR = -1%; SS = -2.9%). PRT and CMJ values did not change following any interventions. Our findings suggest that VFR might be a favorable warm-up routine if the goal is to acutely increase ROM without compromising functional performance.

An Intense Warm-Up Does Not Potentiate Performance Before or After a Single Bout of Foam Rolling.

Foam rolling (FR) is a common intervention used as a warm-up to increase the range of motion (ROM) of a joint, without changes in subsequent performance. It has been shown that, in similar techniques (e.g., stretching), an additional intense warm-up can lead to performance potentiation. However, to date, it is not clear if this also holds true for FR, and if this effect is similar in both sexes. Thus, the purpose of this study was to compare the effects of an intense warm-up either before or after FR with the effects of FR without any additional intense warm-up, in both females and males. In total, 27 volunteers (14 male, 13 female) visited the laboratory on three separate days. Each participant was randomly assigned to one of the three interventions. ROM was assessed with a Sit n' Reach box, and countermovement jump (CMJ) height with a force plate, both before and after the interventions. In addition, maximum voluntary isometric contraction (MVIC) peak torque and maximum voluntary dynamic contraction (MVDC) peak torque were assessed with a dynamometer. ROM increased to the same extent following the interventions in all groups, with a large magnitude of change (P < 0.001; d = 1.12 to 1.83). In addition, male participants showed significantly higher increases in ROM when the intense warm-up was performed after FR (P < 0.001; d = 1.44), but not without the intense warm-up (P = 0.45; d = 0.57) or when the intense warm-up was performed before FR (P = 0.24; d = 0.69). No significant changes in CMJ height, MVIC peak torque, or MVDC peak torque were observed (P > 0.05). We therefore conclude that the time-efficient athlete might skip further intense warm-up, besides FR, when the goal is to increase ROM and to sustain performance parameters.

A comparison of foam rolling and vibration foam rolling on the quadriceps muscle function and mechanical properties.

PURPOSE: The purpose of the study was to investigate the effects of using a vibration foam roll (VFR) or a non-vibration foam roll (NVFR) on maximum voluntary isometric contraction peak torque (MVIC), range of motion (ROM), passive resistive torque (PRT), and shear modulus. METHODS: Twenty-one male volunteers visited the laboratory on two separate days and were randomly assigned to either a VFR group or a NVFR group. Both interventions were performed for 3 × 1 min each. Before and after each intervention, passive resistive torque and maximum voluntary isometric contraction peak torque of the leg extensors were assessed with a dynamometer. Hip extension ROM was assessed using a modified Thomas test with 3D-motion caption. Muscle shear modulus of the vastus lateralis (VL), vastus medialis (VM), and rectus femoris (RF) was assessed with shear wave elastography (SWE). RESULTS: In both groups (VFR, NVFR) we observed an increase in MVIC peak torque (+ 14.2 Nm, + 8.6 Nm) and a decrease in shear modulus of the RF (- 7.2 kPa, - 4.7 kPa). However, an increase in hip extension ROM (3.3°) was only observed in the VFR group. There was no change in PRT and shear modulus of the VL and VM, in both the VFR group and the NVFR group. Our findings demonstrate a muscle-specific acute decrease in passive RF stiffness after VFR and NVFR, with an effect on joint flexibility found only after VFR. CONCLUSION: The findings of this study suggest that VFR might be a more efficient approach to maximize performance in sports with flexibility demands.

The Accumulated Effects of Foam Rolling Combined with Stretching on Range of Motion and Physical Performance: A Systematic Review and Meta-Analysis.

Although it is well known that both stretching and foam rolling can acutely increase the range of motion (ROM) and affect performance, the effects of a combined treatment (foam rolling and stretching) are not yet clear. Hence, the purpose of this meta-analysis was to compare the combined effect to that of stretching or foam rolling alone on both ROM and performance. We assessed the effect of a combined treatment on ROM and compared it to the effect of stretching, foam rolling, and a control condition by applying a random-effect meta-analysis. We also applied the same model to compare the effect of the combined treatment on performance. Moreover, by applying a mixed-effect model, we performed subgroup analyses with the stretching technique, type of foam rolling, tested muscles, type of task, and the order of the combined treatment. We found a significant overall effect on ROM change when comparing the combined treatment with the control condition (effect size (ES) = -0.332); however, no significant effect was found when comparing it to stretching (ES = 0.032) or foam rolling alone (ES = -0.225). The meta-analysis revealed no significant overall effect on performance when the combined treatment was compared to stretching alone (ES = -0.029). However, the subgroup analysis for performance revealed a superior effect for the combined treatment compared to stretching alone, but only if foam rolling was followed by stretching (ES = -0.17), and not vice versa. Athletes do not have to combine stretching with foam rolling since no additional effect was observed. However, to increase performance, the combination of foam rolling followed by stretching can lead to greater improvements.

The Time Course of Muscle-Tendon Unit Function and Structure Following Three Minutes of Static Stretching.

While the time course of muscle-tendon unit (MTU) function and structure following short (1 min) and long (5 min) durations of static stretching has already been investigated, less is known about medium stretch durations. Therefore, the purpose of this study was to investigate the time course of these parameters following 3 min of static stretching of the plantar flexor muscles. Fourteen healthy volunteers were tested on two separate days in a random order with two different rest times (0 min, 5 min) after 3 × 60 s of stretching. During each test, the dorsiflexion range of motion (RoM), passive resistive torque (PRT), and maximum voluntary contraction (MVC) were measured with a dynamometer. Ultrasonography of the gastrocnemius medialis (GM) muscle-tendon junction displacement and motion capture allowed us to determine the length changes in the tendon and muscle, respectively, and hence to calculate their stiffness. We observed an increase in RoM and a decrease in PRT and muscle-tendon stiffness at 0 min and 5 min post-stretching. This can be attributed to a decrease in muscle stiffness, as a decrease in PRT and muscle stiffness was observed up to 5 min after the stretching. No changes were detected in MVC torque and tendon stiffness. Static stretching for 3 × 60 s changes the muscle-tendon functions (RoM, PRT) for at least 5 min. These changes are related to mechano-morphological changes of the muscle, but not the tendon structure.

The Acute Effects of a Percussive Massage Treatment with a Hypervolt Device on Plantar Flexor Muscles' Range of Motion and Performance.

Handheld percussive massage treatment has gained popularity in recent years, for both therapeutic use and in sports practice. It is used with the goals of increasing flexibility and performance, but also to accelerate recovery. However, until now, there has been no scientific evidence, which proves such effects. Therefore, the purpose of this study was to investigate the effects of a 5-min percussion treatment of the calf muscles on range of motion (ROM) and maximum voluntary contraction (MVC) torque of the plantar flexor muscles. Sixteen healthy male volunteers (mean ± SD; 27.2 ± 4.2 years, 1.79 ± 0.05 m, 79.4 ± 9.1 kg) were tested on two separate days with either a 5-min massage treatment of the calf muscles with a Hypervolt device or the control condition (sitting only). Before and after the treatments, dorsiflexion ROM and MVC torque of the plantar flexor muscles were measured with a dynamometer. Maximum dorsiflexion ROM increased with a large magnitude following the massage treatment by 5.4° (+18.4%; p = 0.002, d= 1.36), while there was no change in the control group. Moreover, MVC torque did not change following both the massage treatment and the control treatment. Similar to a conventional massage by a therapist, ROM can be increased by a handheld percussive massage treatment without having an effect on muscle strength.

Five minutes static stretching influences neural responses at spinal level in the background of unchanged corticospinal excitability.

OBJECTIVES: Corticospinal tract excitability and spinal reflex pathways are transiently affected by short applications of static stretching. However, it remains unclear whether the duration and magnitude of these neurophysiological responses can be increased with a longer duration of the applied stretch. The purpose of this study was to investigate alterations in cortical and spinal excitability following five minutes static stretching. METHODS: Seventeen participants (22.8±2.3 years old) were tested for the tendon tap reflex (T-reflex), Hoffman reflex (H-reflex) and motor-evoked potentials (MEPs) after transcranial magnetic stimulation (TMS) of the ankle flexor muscles in two separate occasions: before and after 5 minute static stretching or 5 minute control period, in a randomized order. RESULTS: No changes were observed following the control condition. H/M ratio increased by 16.2% after stretching (P=.036). Furthermore, immediately after stretching it was observed a strong inhibition of the T-reflex (57.6% inhibition, P=.003) that persisted up to five minutes after stretching (16.2% inhibition, P=.013) but returned to baseline following 10 minutes. MEPs were not affected by stretching. CONCLUSIONS: This study suggests that the neuromuscular responses that follow five minute of static stretching do not influence the excitability of the corticospinal tract and follow a different time course within spinal reflex pathways.

The Effect of Functional Home-Based Strength Training Programs on the Mechano-Morphological Properties of the Plantar Flexor Muscle-Tendon Unit in Children With Spastic Cerebral Palsy.

PURPOSE: The purpose of this study was to investigate the effects of functional progressive resistance training (PRT) and high-intensity circuit training (HICT) on the mechano-morphological properties of the plantar flexor muscle-tendon unit in children with spastic cerebral palsy. METHODS: Twenty-two children (12.8 [2.6] y old, Gross Motor Function Classification System levels I/II = 19/3) were randomly assigned to either a PRT group or an HICT group. The interventions consisted of functional lower limb exercises, which were performed at home 3 times per week for 8 weeks. Measurements at baseline, preintervention, postintervention, and follow-up were taken to assess ankle joint range of motion and the properties of the gastrocnemius medialis, vastus lateralis, rectus femoris, and Achilles tendon (eg, thickness, strength, stiffness). RESULTS: Despite a nonsignificant increase in active torque in the HICT group, neither gastrocnemius medialis morphology nor Achilles tendon properties were significantly altered after the interventions. Vastus lateralis thickness increased following PRT only. CONCLUSIONS: Functional home-based strength training did not lead to significant changes at the muscular level in children with cerebral palsy. We therefore assume that a more specific stimulus of higher intensity combined with a longer training duration might be necessary to evoke changes in muscles and tendons in individuals with cerebral palsy.

Ultrasound as a Tool to Study Muscle-Tendon Functions during Locomotion: A Systematic Review of Applications.

Movement science investigating muscle and tendon functions during locomotion utilizes commercial ultrasound imagers built for medical applications. These limit biomechanics research due to their form factor, range of view, and spatio-temporal resolution. This review systematically investigates the technical aspects of applying ultrasound as a research tool to investigate human and animal locomotion. It provides an overview on the ultrasound systems used and of their operating parameters. We present measured fascicle velocities and discuss the results with respect to operating frame rates during recording. Furthermore, we derive why muscle and tendon functions should be recorded with a frame rate of at least 150 Hz and a range of view of 250 mm. Moreover, we analyze why and how the development of better ultrasound observation devices at the hierarchical level of muscles and tendons can support biomechanics research. Additionally, we present recent technological advances and their possible application. We provide a list of recommendations for the development of a more advanced ultrasound sensor system class targeting biomechanical applications. Looking to the future, mobile, ultrafast ultrasound hardware technologies create immense opportunities to expand the existing knowledge of human and animal movement.

Does Home-Based Progressive Resistance or High-Intensity Circuit Training Improve Strength, Function, Activity or Participation in Children With Cerebral Palsy?

OBJECTIVE: Does home-based progressive resistance or high-intensity circuit training improve strength, function, activity, or participation in children with cerebral palsy (CP)? DESIGN: This was the first study on high-intensity circuit training for children with CP. This study was conducted as a randomized prospective controlled pilot study. SETTING: Evaluation took place at the gait laboratory of the university hospital, training sessions were performed at home. PARTICIPANTS: Children (N=22) with CP (average age: 12y, 10mo, 19 Gross Motor Function Classification System level I, 3 level II) were randomly assigned either to progressive resistance training (PRT) or high-intensity circuit training (HICT). INTERVENTIONS: The PRT group trained with progressive overload, while the HICT group performed as many repetitions as possible within 30-second intervals (8wk, 3 times weekly in both groups). MAIN OUTCOME MEASURES: Outcome measures stretched over all domains of the International Classification of Functioning, Disability and Health and included muscle strength, muscle power sprint test (MPST), timed stairs test (TST), 6-minute walking test, Gait Profile Score (GPS), timed Up and Go test (TUGT) and participation questionnaires. RESULTS: Only the HICT group was able to improve strength. Furthermore, the HICT group scored better in the MPST, while PRT participants improved in the TST and TUGT. The HICT-group was able to show improvement in the subscores of the parent-reported participation questionnaire. Other measures of mobility or participation did not change. CONCLUSIONS: Both programs improved function specific to intervention. However, only the HICT group showed significant strength and participation improvements. Compliance was decent in both groups, but the average training unit was shorter in the HICT group. Both exercise programs showed functional benefits, but HICT might be the preferable option for strengthening in highly functional children with CP.

Correction to: Muscle and tendon morphology alterations in children and adolescents with mild forms of spastic cerebral palsy.

Following publication of the original article [1], the author requested for an acknowledgement to retrospectively be added to the 'Acknowledgements' section of the article [1].

Muscle and tendon morphology alterations in children and adolescents with mild forms of spastic cerebral palsy.

BACKGROUND: Early detection of changes at the muscular level before a contracture develops is important to gain knowledge about the development of deformities in individuals with spasticity. However, little information is available about muscle morphology in children with spastic diplegic cerebral palsy (CP) without contracture or equinus gait. Therefore, the aim of this study was to compare the gastrocnemius medialis (GM) and Achilles tendon architecture of children and adolescents with spastic CP without contracture or equinus gait to that of typically developing (TD) children. METHODS: Two-dimensional ultrasonography was used to assess the morphological properties of the GM muscle and Achilles tendon in 10 children with spastic diplegic CP (Gross Motor Function Classification System level I-II) and 12 TD children (mean age 12.0 (2.8) and 11.3 (2.5) years, respectively). The children with CP were not restricted in the performance of daily tasks, and therefore had a high functional capacity. Mean muscle and tendon parameters were statistically compared (independent t-tests or Mann-Whitney U-tests). RESULTS: When normalized to lower leg length, muscle-tendon unit length and GM muscle belly length were found to be significantly shorter (p < 0.05, effect size (ES) = 1.00 and 0.98, respectively) in the children with spastic CP. Furthermore, there was a tendency for increased Achilles tendon length when expressed as a percentage of muscle-tendon unit length (p = 0.08, ES = - 0.80) in the individuals with CP. This group also showed shorter muscle fascicles (3.4 cm vs. 4.4 cm, p < 0.01, ES = 1.12) and increased fascicle pennation angle (21.9° vs. 18.1°, p < 0.01, ES = - 1.36, respectively). However, muscle thickness and Achilles tendon cross-sectional area did not differ between groups. Resting ankle joint angle was significantly more plantar flexed (- 26.2° vs. - 20.8°, p < 0.05, ES = 1.06) in the children with CP. CONCLUSIONS: Morphological alterations of the plantar flexor muscle-tendon unit are also present in children and adolescents with mild forms of spastic CP. These alterations may contribute to functional deficits such as muscle weakness, and therefore have to be considered in the clinical decision-making process, as well as in the selection of therapeutic interventions.