Effect of split posterior tibialis tendon transfer on foot progression angle in children with cerebral palsy.

OBJECTIVES: A common orthopedic issue for patients with spastic cerebral palsy (CP) is hindfoot varus deformity. One method of treatment is the split posterior tibialis tendon transfer (SPOTT). There is limited literature on the effect of SPOTT on foot progression angle (FPA) in children with CP who have equinovarus deformities. The objective of our study was to evaluate the change in FPA after SPOTT to determine if this procedure can improve FPA. RESEARCH QUESTION: This study aims to determine what axial changes are generated from a split posterior tibial tendon transfer in children with CP. METHODS: We performed a retrospective analysis of all ambulatory children with a diagnosis of CP who underwent SPOTT at our institution. Patients with bony rotational procedures were excluded. Descriptive statistics including mean and standard deviation (SD) were used to characterize continuous variables. Paired t-tests were used to evaluate outcomes, in which a target outcome was defined as a post-operative FPA between 0-10° of external rotation. RESULTS: 44 limbs were included. Demographics were as follows: 26/13 female/male; mean age[SD] (years): 9.8[3.5]; 30 hemiplegic, 9 diplegic, and 1 triplegic. Of the 44 limbs, 18 limbs had a target outcome, 4 had no change, and 22 had a non-target outcome. Of the 22 with an outcome outside of the target, 4 limbs trended away from a target outcome. The overall change in FPA measured was - 10.9 ± 14.7° (p < 0.0001) Age at time of surgery, CP involvement, pre-operative FPA, and GMFCS level were not predictors of outcome (p > 0.05). CONCLUSIONS: SPOTT produced a change of 10.9° external rotation in FPA post-operatively and its effects should be considered when planning a SEMLS.

The association between isometric strength and cognitive function in adults with cerebral palsy.

Background: The literature supports quantifying the maximum force/tension generated by one's forearm muscles such as the hand grip strength (HGS) to screen for physical and cognitive frailty in older adults. Thus, we postulate that individuals with cerebral palsy (CP), who are at higher risk for premature aging, could benefit from tools that objectively measure muscle strength as a functional biomarker to detect frailty and cognitive decline. This study assesses the clinical relevancy of the former and quantifies isometric muscle strength to determine its association with cognitive function in adults with CP. Methods: Ambulatory adults with CP were identified from a patient registry and were enrolled into this study. Peak rate of force development (RFD) and maximum voluntary isometric contraction of the quadriceps were measured using a commercial isokinetic machine, while HGS was collected with a clinical dynamometer. Dominant and non-dominant side were identified. Standardized cognitive assessments, including the Wechsler Memory and Adult Intelligence Scales IV, Short Test of Mental Status, and the Patient-Reported Outcomes Measurement Information System (PROMIS®) were used to evaluate cognitive function. Results: A total of 57 participants (32 females; mean age 24.3 [SD 5.3]; GMFCS levels I-IV) were included in the analysis. Although dominant and non-dominant RFD and HGS measures were associated with cognitive function, non-dominant peak RFD showed the strongest associations with cognitive function. Conclusion: RFD capacity may reflect age-related neural and physical health and could be a better health indicator than HGS in the CP population.

Quantitative measures of motor development in Angelman syndrome.

Angelman Syndrome is a rare neurodevelopmental disorder characterized by developmental delay, lack of speech, seizures, intellectual disability, characteristic behavior, and movement disorders. Clinical gait analysis provides the opportunity for movement quantification to investigate an observed maladaptive change in gait pattern and offers an objective outcome of change. Pressure-sensor-based technology, inertial and activity monitoring, and instrumented gait analysis (IGA) were employed to define motor abnormalities in Angelman syndrome. Temporal-spatial gait parameters of persons with Angelman Syndrome (pwAS) show deficiencies in gait performance through walking speed, step length, step width, and walk ratio. pwAS walk with reduced step lengths, increased step width, and greater variability. Three-dimensional motion kinematics showed increased anterior pelvic tilt, hip flexion, and knee flexion. PwAS have a walk ratio more than two standard deviations below controls. Dynamic electromyography showed prolonged activation of knee extensors, which was associated with a decreased range of motion and the presence of hip flexion contractures. Use of multiple gait tracking modalities revealed that pwAS exhibit a change in gait pattern to a flexed knee gait pattern.  Cross-sectional studies of individuals with AS show a regression toward this maladaptive gait pattern over development in pwAS ages 4-11. PwAS unexpectedly did not have spasticity associated with change in gait pattern. Multiple quantitative measures of motor patterning may offer early biomarkers of gait decline consistent with critical periods of intervention, insight into appropriate management strategies, objective primary outcomes, and early indicators of adverse events.

Rectus femoris transfers with and without a hamstring lengthening will not change hip kinematics in children with cerebral palsy.

BACKGROUND: A rectus femoris transfer (RFT) surgery with and without a hamstring lengthening (HSL) is used to treat stiff-knee gait in children with cerebral palsy (CP). While current literature has reported that a RFT surgery improves the kinematics at the knee, little is known about the kinematic changes at the hip. RESEARCH QUESTION: Does a RFT surgery change hip joint kinematics in children with CP? METHODS: This retrospective study included children (<18 years old) diagnosed with CP, who underwent a RFT procedure, and who were seen at our institution's accredited clinical motion laboratory. Patients with both pre- and post-operative gait analysis were identified and comparison between those analyses were performed to identify kinematic differences at the hip and knee. A total of 66 legs from 46 children (mean age: 11.1 ± 3.6) met the inclusion criteria. RESULTS: Overall results revealed that a RFT did not change kinematics at the hip [p > 0.05], however, a RFT did increase the maximum knee flexion during the swing period [Mean Difference Post - Pre: 8.3°, 95% CI: 4.9-11.8, p < 0.0001]. Additionally, it was found that changes in hip extension during the terminal stance phase were significantly different between the combined RFT and HSL compared to solely an RFT. The results of this study also revealed that children whose stiff-knee gait did not improve, tended to have increased hip external rotation during terminal stance and swing and greater hip extension during terminal stance, compared to children whose stiff-knee gait did improve. SIGNIFICANCE: Overall, a RFT with and without a HSL surgery improves hip and knee kinematics in the sagittal plane, however, improvements at the hip were not clinically significant. As a result, a RFT or a combined RFT with HSL should not be used to change hip kinematics in children with CP.

Associations of Circulating Insulin-Growth Factor-1 With Cognitive Functions and Quality of Life Domains in Ambulatory Young Adults With Cerebral Palsy: A Pilot Study.

Objective: Adults with cerebral palsy (CP) often have impaired cognitive functions. CP also has deteriorations in multiple quality-of-life (QoL) domains. The bio-psycho-social health psychology model posits that biological factor interacts with social and psychological functions. However, the biological determinant of psycho-social and functional outcomes in CP has been scarcely examined. Circulating Insulin-like growth factor-1 (IGF-1) is associated with cognitive deficits in older adults, we thus aimed to examine the associations of circulating IGF-1 with: (1) objectively measured cognitive functions, (2) self-reported cognitive functions, and (3) QoL measures in adults diagnosed with CP. Methods: Seventy-two adults with CP and varying degrees of cognitive functions were recruited from an accredited clinical motion analysis laboratory at a regional Children's Hospital. Circulating IGF-1 was measured using post-fasting serum. The Wechsler Adult Intelligence Scale (WAIS) tests were administered to assess multiple cognitive functions, whereas the Patient-Reported Outcomes Measurement Information System (PROMIS) was used to measure multiple domains of self-reported health, including cognitive complaints and eight QoL domains. Results: Sixty-eight participants had complete data [mean age = 25 (SD = 5.3), female = 52.8%]. Controlling for covariates, circulating IGF-1 was associated with multiple cognitive domains, including positively with declarative memory and executive function and inversely with visual-spatial and motor skills, and processing speed, while no association with subjective memory complaint was detected. Circulating IGF-1 was also inversely associated with four QoL domains, including depressive symptoms, executive function, physical function, and social roles and activities. Conclusions: In CP, circulating IGF-1 might be a useful biological determinant of objective cognitive functions and several quality-of-life domains commonly impaired in CP.

Walking speed and patient-reported outcomes in young adults with cerebral palsy.

AIM: To examine the relationship between quantitative gait measurements and self-reported physical, psychological, cognitive, and social function status in young adults with cerebral palsy (CP). METHOD: Seventy-two adults with CP (range 18-48y; median age 23y [interquartile range 21-27y]; 34 males, 38 females), in Gross Motor Function Classification System levels I to IV, who previously underwent an instrumented gait analysis (IGA) at our center as children were recruited. Participants underwent a repeated IGA. National Institutes of Health Patient-Reported Outcomes Information System (PROMIS) instruments including the PROMIS-57, Applied Cognition - General Concerns (Short Form), and Applied Cognition - Executive Function (Short Form) were administered. Data derived from current and prior IGA were compared via non-parametric correlation analysis with PROMIS subscores. RESULTS: Subscores for anxiety, depression, sleep, and fatigue did not significantly correlate with any IGA data. Walking speed, adjusted for stature, correlated strongly with multiple subscores: physical function (p<0.001, rs =0.708); participation in social roles (p=0.007, rs =0.319); executive function (p=0.005, rs =0.335). Pain interference correlated with longitudinal change in adjusted walking speed (p=0.032, rs =-0.259). The Applied Cognition - General Concerns (Short Form) correlated with prior absolute walking speed, but not adjusted values. INTERPRETATION: This study underscores the importance of walking speed and its association with a variety of functional domains in adults with CP. WHAT THIS PAPER ADDS: Patient-Reported Outcomes Information System measures provide useful clinical data in young adults with cerebral palsy. Temporospatial gait parameters have wide-reaching functional influence in this population. Walking speed is strongly correlated with physical, social, and executive function.

Increased plasma brain-derived neurotrophic factor (BDNF) as a potential biomarker for and compensatory mechanism in mild cognitive impairment: a case-control study.

BACKGROUND: Previous meta-analyses examining the continuum of Alzheimer's disease (AD) concluded significantly decreased peripheral brain-derived neurotrophic factor (BDNF) in AD. However, across different meta-analyses, there remain inconsistent findings on peripheral BDNF levels in individuals with mild cognitive impairment (MCI). This issue has been attributed to the highly heterogenous clinical and laboratory factors. Thus, BDNF's level, discriminative accuracy for identifying all-cause MCI and its subtypes, and its associations with other biomarkers and neurocognitive domains, remain largely unknown. METHODS: To address this heterogeneity, we compared a healthy control cohort (n=56, 45 female) to an MCI cohort (n=40, 28 female), to determine whether plasma BDNF, hs-CRP, and DHEA-S can differentiate healthy from MCI individuals, including two MCI subtypes (amnestic [aMCI] and non-amnestic [non-aMCI]). The associations between BDNF with other biomarkers and neurocognitive tests were examined. Adults with cerebral palsy were included as sensitivity analyses. RESULTS: Compared to healthy controls, BDNF was significantly higher in all-cause MCI, aMCI, and non-aMCI. Furthermore, BDNF had good (AUC=0.84, 95% CI=0.74 to 0.95, p<0.001) and excellent discriminative accuracies (AUC=0.92, 95% CI=0.84 to 1.00, p<0.001) for all-cause MCI and non-amnestic MCI, respectively. BDNF was significantly and positively associated with plasma hs-CRP (ß=0.26, 95% CI=0.02 to 0.50, p=0.038), despite attenuated association upon controlling for BMI (ß=0.15, 95% CI=-0.08 to 0.38, p=0.186). Multiple inverse associations between BDNF and detailed neurocognitive tests were also detected. CONCLUSIONS: These findings suggest BDNF is increased as a compensatory mechanism in preclinical dementia, supporting the neurotrophic and partially the inflammatory hypotheses of cognitive impairment.

Radiographic and plantar pressure assessment of pes planovalgus severity in children with cerebral palsy.

BACKGROUND: Pes planovalgus is common in children with cerebral palsy. Although severity influences treatment, there still lacks standard clinical measurements to objectively quantify pes planovalgus in this population. The comparison of pedobarographic data and radiographic measurements to clinical evaluation has not been reported in this population. METHODS: 395  feet were identified from a population of ambulatory pediatric patients with cerebral palsy. Each patient initially underwent clinical evaluation by an experienced physical therapist who classified feet as: 136 controls, 116 mild, 100 moderate, and 43 severe pes planovalgus. Quantitative measurements were then calculated from antero-posterior and lateral radiographs of the foot. Pedobarographic analysis included the arch index, center of pressure index, and a newly defined medial index. FINDINGS: A multivariate analysis was performed on the radiographic and pedobarographic measurements collected. It identified seven variables that improved objective classification of pes planovalgus severity when utilized together. These include the foot progression angle, initial contact force, arch index, medial index, antero-posterior talonavicular coverage, lateral calcaneal pitch and lateral Meary's angle. While the lateral calcaneal pitch angle statistically differed amongst all severity classes, no pedobarographic value statistically differed between all severity classes. INTERPRETATION: Overall, the combination of radiographic and pedobarographic measurements provides valuable information for objectively classifying severity of pes planovalgus in children with cerebral palsy by utilizing these values together rather than independently. In a clinical setting, radiographs and pedobarographic data may be obtained to enhance assessment of severity and guide treatment.

Commonalities in biomarkers and phenotypes between mild cognitive impairment and cerebral palsy: a pilot exploratory study.

Clinically, individuals with cerebral palsy (CP) experience symptoms of accelerated biological aging. Accumulative deficits in both molecular underpinnings and functions in young adults with CP can lead to premature aging, such as heart disease and mild cognitive impairment (MCI). MCI is an intermediate stage between healthy aging and dementia that normally develops at old age. Owing to their intriguingly parallel yet "inverted" disease trajectories, CP might share similar pathology and phenotypes with MCI, conferring increased risk for developing dementia at a much younger age. Thus, we examined this hypothesis by evaluating these two distinct populations (MCI= 55, CP = 72). A total of nine measures (e.g., blood biomarkers, neurocognition, Framingham Heart Study Score (FHSS) were compared between the groups. Compared to MCI, upon controlling for covariates, delta FHSS, brain-derived neurotrophic factor (BDNF) levels, and systolic blood pressure were significantly lower in CP. Intriguingly, high-sensitivity CRP, several metabolic outcomes, and neurocognitive function were similar between the two groups. This study supports a shared biological underpinning and key phenotypes between CP and MCI. Thus, we proposed a double-hit model for the development of premature aging outcomes in CP through shared biomarkers. Future longitudinal follow-up studies are warranted to examine accelerated biological aging.

Peak sagittal plane spine kinematics in female gymnasts with and without a history of low back pain.

BACKGROUND: Female gymnasts have a greater prevalence of back pain compared to other female athletes. There is little evidence that female artistic gymnasts with and without back pain demonstrate different movement patterns during gymnastics skills. The purpose of this study was to determine if there were differences in back movements during back walkovers and back handsprings among female artistic gymnasts. METHODS: Female artistic gymnasts (8-18 years old) with and without back pain wore inertial sensors on their torso, arms, and legs while performing back walkovers (N = 14) and back handsprings (N = 15) on the floor and balance beam at their training gymnastics facilities. FINDINGS: Gymnasts with back pain had similar spine peak extension, peak flexion, and range of motion during back walkovers and back handsprings compared to gymnasts without back pain. Additionally, no differences in sagittal plane spine kinematics were found between the groups at any specific time point during either the back walkover or back handspring skills. However, a large portion of the data collected was excluded during quality assurance, thus our final sample sizes are small. INTERPRETATION: These findings suggest that gymnasts with back pain have similar sagittal plane movements to those without back pain. The relationship between back pain and gymnastics training load/intensity is currently unclear. We suggest future studies to investigate common artistic gymnastics skills and back pain prevalence with more participants, full-body motion analysis with kinetic measurement capabilities, and longitudinally for those demonstrating back pain.

Self-reported physical function is associated with walking speed in adults with cerebral palsy.

PURPOSE: To understand the relationship of walking speed to self-reported pain, fatigue, and physical function in adults with CP. METHODS: Design: Cross-sectional study. SETTING: Accredited clinical motion analysis laboratory in a regional children's hospital. PARTICIPANTS: 72 ambulatory patients ⩾ 18 years of age, diagnosed with CP, who previously had ⩾ 1 prior instrumented gait analysis at our facility. MAIN OUTCOME MEASURES: PROMIS-57 pain interference/intensity, physical function, and fatigue measures and walking speed. RESULTS: Physical function was significantly lower than able-bodied normal values by 1-2 standard deviations (40.3 ± 8.5). Pain interference (51.4 ± 9.0) and fatigue (50.2 ± 9.2) were not significantly different when compared to able-bodied normal values. Only physical function was statistically correlated with walking speed (p< 0.001), while pain interference (p= 0.39), pain intensity (p= 0.36), and fatigue (p= 0.75) were not. Pain interference, pain intensity, and fatigue were not statistically significant factors in the multiple regression of walking speed. Fatigue could significantly predict physical function, pain interference, and pain scores (p= 0.032, p< 0.001, p< 0.01, respectively), however, fatigue did not directly predict walking speed (p= 0.747). CONCLUSIONS: Self-reported physical function correlates with objectively measured walking speed in young adults with CP while patient-reported pain and fatigue did not, contrary to what would be predicted by the literature.

Prevalence of metabolic syndrome and cardiovascular disease risk factors in adults with cerebral palsy.

AIM: To investigate the prevalence of metabolic syndrome and cardiovascular disease (CVD) risk factors and the association between common metabolic markers and Gross Motor Function Classification System (GMFCS) levels in ambulatory adults with cerebral palsy (CP). METHOD: Metabolic markers and GMFCS levels were evaluated in a cross-sectional study of 70 ambulatory adults with CP (34 males, 36 females; mean age 24y 5mo [SD 5y 4mo], range 18y 6mo-48y 8mo) to determine the prevalence of metabolic syndrome and CVD risk factors, and were compared to age-matched, population norms from the National Health and Nutrition Examination Survey (NHANES) registry. The Framingham Heart Study (FHS) CVD risk estimation was also used to evaluate an individual's risk for CVD. RESULTS: Metabolic syndrome was identified in 17.1% of the cohort, higher than the 10% in the NHANES registry. The FHS CVD 30-year lipid and body mass index (BMI)-based risk factor results showed that 20% to 40% of the cohort was at greater risk of developing CVD (BMI-based: 39.7% 'full' CVD risk factor; lipid-based: 26.5% 'full' CVD risk factor) as compared to the FHS normative population data. There was a positive correlation between GMFCS level, waist circumference (r=0.28, p=0.02), and waist-to-hip ratio (r=0.28, p=0.02). INTERPRETATION: Adults with CP are at higher risk of CVD and metabolic syndrome compared to the general population, which is probably because of impaired mobility.

Relative phase measures of intersegmental coordination describe motor control impairments in children with cerebral palsy who exhibit stiff-knee gait.

BACKGROUND: The purpose of this retrospective study was to explore lower limb intersegmental coordination as a clinically important indicator of motor control mechanisms in individuals with cerebral palsy exhibiting stiff-knee gait. We used the relative phase of thigh and foot segments around foot-off to describe motor control, given the relevance of the pre-swing phase of gait to the existence of stiff-knee gait. METHODS: Traditional gait parameters and thigh/foot intersegmental coordination were calculated using pre-and postoperative kinematic data from a cohort of 54 subjects (92 legs) with spastic cerebral palsy. All participants had stiff-knee gait, walked without assistive devices, and underwent rectus femoris transfer surgery to improve swing period knee flexion. Analyses included correlations between a) preoperative intersegmental coordination and gait variables (knee flexion range, rate and gait performance) and b) pre-to-postoperative intersegmental coordination change and change in gait variables. FINDINGS: Thigh/foot intersegmental coordination significantly (P < 0.001) correlated with knee flexion range, rate and walking speed. Postoperative intersegmental coordination was significantly more uncoupled than preoperative. Pre-to-postoperative intersegmental coordination improvement also significantly correlated with improvements in knee flexion range, rate and walking speed. Pre-to-postoperative changes in intersegmental coordination accounted for 43% and 36% of variance in knee flexion range change and knee flexion rate change respectively. INTERPRETATION: Intersegmental coordination is a clinically important factor in knee flexion limitations associated with stiff-knee gait for individuals with cerebral palsy. These findings are a foundation for further study of intersegmental coordination measures as complements to traditional instrumented gait analysis.

POSTURAL STABILITY AND KINETIC CHANGE IN SUBJECTS WITH PATELLOFEMORAL PAIN AFTER A NINE-WEEK HIP AND CORE STRENGTHENING INTERVENTION.

BACKGROUND: Idiopathic patellofemoral pain (PFP) has been linked to hip weakness and abnormal lower extremity mechanics. The effect of a strengthening intervention on balance has not been well studied among individuals with PFP. HYPOTHESIS/PURPOSE: The primary aim of this study was to evaluate changes in center of pressure displacement during the single limb squat following a nine-week physical therapy intervention among adolescent females with PFP. STUDY DESIGN: Interventional and cross-sectional. METHODS: Seven adolescent females with PFP (10 extremities) were included in the study. Center of Pressure (CoP) excursions during a single limb squat task were measured before and after a nine week of physical therapy intervention focused on strengthening of the hip and core. Seven asymptomatic females were matched to the PFP group on the basis of age and activity level, and were tested as a reference group. CoP trajectories were reduced into four variables: mean distance (MDIST), root-mean-square distance (RDIST), range (RANGE), and 95% confidence interval circle area (AREA-CC). Maximum knee flexion angle, peak knee power generation and absorption were also recorded. Linear mixed models were used to test for within and between group differences in CoP metrics. RESULTS: Pre-intervention, CoP range, knee power absorption and generation were significantly decreased in the PFP group relative to the reference group. Post-intervention, the PFP group reported a significant decrease in symptom severity. There was also a significant (p<0.05) increase in MDIST, RDIST, RANGE, AREA-CC, peak knee flexion angle, peak power absorption and power generation. There was no difference (p>0.05) in knee flexion, knee power or CoP displacement between the two groups after the physical therapy intervention. CONCLUSION: Hip and core-strengthening resulted in a significant decrease in symptom severity as well as significant reductions in CoP displacement. LEVEL OF EVIDENCE: 3.

Analysis of Reach-to-Grasp by School-Aged Children with Down Syndrome Elucidates Limitations in Upper Extremity Motor Control.

AIMS: To identify limitations in preparatory planning (PP) and movement execution that constrain performance of reach-to-grasp (RTG) movements in school-aged children with Down syndrome (DS) and examine the effect of chronological age (CA) on performance. METHODS: Nine children with DS ages 6 to 12 years and nine with typical development (TD) participated in this pilot descriptive study. Three-dimensional kinematic analysis was applied to RTG movements performed in the context of two functional tasks. RESULTS: PP variables focused on the coordination of reach and grasp. Compared to the group with TD, the group with DS demonstrated significant limitations in anticipatory slowing down of hand transport and orientation of the hand in preparation for object contact. There was also relatively late onset of preparatory grip formation in the group with DS. In regard to movement execution, reach trajectories of the group with DS showed significantly greater deviation from the straight path. Correlations of study variables with CA were low and insignificant in both groups. CONCLUSIONS: Motor control mechanisms that mediate both PP and execution of the fundamental RTG movement are potential factors limiting upper extremity activity in school-aged children with DS. They should be addressed in future intervention-based research.

Biomechanical Assessment of Patellar Advancement Procedures for Patella Alta.

Crouch gait deformity is common in children with cerebral palsy and often is associated with patella alta. Patellar tendon advancement typically is used to correct patella alta and restore normal knee mechanics. The purpose of this study was to determine the mechanical strength of surgical constructs used for fixation during patellar advancement procedures. This study used a cadaveric model to determine which of 3 surgical techniques is biomechanically optimal for patellar tendon advancement in treating patella alta. Twenty-four human cadaveric knees (8 per group) were prepared using 1 of 3 different common surgical techniques: tibial tubercle osteotomy, patellar tendon partial resection and repair at the distal patella, and patellar tendon imbrication. The patella was loaded from 25 to 250 N at 1 Hz for 1000 cycles. A significant difference in patella displacement under cyclical loading was found between surgical techniques. Tibial tubercle osteotomy exhibited significantly less displacement under cyclical loading than distal patella excision and repair (P<.0001) or imbrication (P=.0088). Imbrication exhibited significantly less displacement than distal patella excision and repair (P=.0006). Tibial tubercle osteotomy survived longest. Based on failure criteria of 5 mm of displacement, tibial tubercle osteotomy lasted between 250 and 500 cycles. The other 2 techniques failed by 25 cycles. This study offers quantitative evidence regarding the relative mechanical strength of each construct and may influence choice of surgical technique. [Orthopedics. 2016; 39(3):e492-e497.].

Sagittal plane coordination dynamics of typically developing gait.

BACKGROUND: Individuals who undergo an instrumented gait analysis often have an aberrant gait pattern due to neuromuscular impairments that adversely affect their coordination. Conventional instrumented gait analysis descriptors fail to capture the complex coordination dynamics of gait. This paper presents a straightforward methodology for generating descriptors of coordination dynamics based on dynamical systems theory and provides the largest reported dataset of sagittal plane coordination measures, including adjacent and non-adjacent segment pairings, from individuals free of gait pathology walking over-ground. METHODS: Tri-planar marker trajectories from 104 unimpaired subjects between the ages of 8 and 66 years were collected as they walked at a self-selected speed on a level surface. Phase portraits for the pelvis, thigh, shank, and foot and continuous relative phase diagrams for the segment pairs of pelvis-thigh, thigh-shank, shank-foot, and thigh-foot were calculated. FINDINGS: The low coefficients of variation for each coordination curve are comparable to inter-subject coefficients of variation for kinematic curves, narrow confidence intervals for relative phase angles at four essential footfall conditions, and small standard deviation bands of the continuous relative phase diagrams are evidence that these curves characterize the coordination dynamics of normal gait. INTERPRETATION: These findings support the use of this normative dataset as a reference for coordination studies in the clinic or research laboratory. Improving our understanding of gait strategies from the level of coordination and characterizing the natural variability in gait patterns offer a means to enhance our understanding of atypical gait patterns.