Effects of non-specific low back pain on static balance in emerging adults.

BACKGROUND: Postural control impairments in middle-aged or older people with chronic low back pain (CLBP) have been extensively documented. However, little is known about changes in postural control early in the disease process which may underlie compensatory movement strategies. OBJECTIVE: Our purpose was to quantify postural sway and sensory weighting in emerging adults with and without CLBP. METHODS: Nineteen emerging adults with CLBP (age = 18-26 years (21.11 ± 1.73)) and 19 matched peers without CLBP (18-27 years (22.20 ± 1.97)) participated in a cross-sectional study. Displacement of the center of mass during Quiet stance (QS), Tandem stance (TS), and Unilateral stance (US) on 2 surfaces (stable, unstable) were used to assess postural sway. Sensory Organization Test (SOT) was used to assess sensory weighting. RESULTS: Emerging adults with CLBP showed large, significant increases in postural sway during unstable TS (p ≤ .020). Participants with CLBP relied more on somatosensory input, as evidenced by lower equilibrium scores during conditions favoring visual (p = .020) or vestibular (p < .001) input during the SOT. CONCLUSION: Emerging adults with CLBP showed postural control impairments related to altered sensory weighting. These findings provide insights into the development of CLBP and its effects on postural control. This information may aid early identification, monitoring, and treatment of individuals in the initial stages of disease development who may have unrecognized postural impairments.

Early Treadmill Practice in Infants Born With Myelomeningocele: A Pilot Study.

PURPOSE: To determine the feasibility of an early treadmill training program for infants with myelomeningocele (MMC) and to measure changes in overt infant motor development and control, including mechanisms underlying the overt changes. METHODS: Ten infants with MMC were initially enrolled: 8 infants completed 12 consecutive months of training, and 2 completed 6 months of training. Training consisted primarily of home-based, parent-administered treadmill stepping practice 5 days per week, 10 minutes per day starting within 6 months postbirth. We measured motor milestones, treadmill steps, spinal-level reflexes, and body composition. RESULTS: Infants showed earlier acquisition of gross motor skills than previously reported. The number of alternating steps performed increased, indicating more complex neuromotor control and strength. Integrity of monosynaptic pathways and body composition were improved after controlling for chronological age. CONCLUSIONS: This study demonstrates the feasibility of using early, home-based treadmill training for infants with MMC starting within 6 months postbirth.

Energy Efficiency in Children With Myelomeningocele During Acute Use of Assistive Devices: A Pilot Study.

Due to increased metabolic demands during walking, ∼50% of children with myelomeningocele transition to wheelchair use during adolescence/early adulthood. The purpose of our pilot study involving children with myelomeningocele was to determine: (a) energy expenditure needs during acute use of common assistive devices and (b) if walking poles are a feasible assistive device. Oxygen uptake was recorded for eight (5-12 years old) children in four conditions: independent, walker, crutches, and poles. Acute pole use did not significantly differ from independent walking net energy consumption or cost. Participants consumed more energy while walking with the walker than independently. Our pilot results suggest that (a) acute use of common assistive devices while walking increases energy consumption and cost versus independent and (b) poles are feasible assistive devices, resulting in slightly increased energy requirements. Poles may have provided "just enough" support with minimal change in energy requirements for our participants and, with practice, may enable children with myelomeningocele to remain community ambulators.

Muscle activation patterns in infants with myelomeningocele stepping on a treadmill.

PURPOSE: To characterize how infants with myelomeningocele (MMC) activate lower limb muscles over the first year of life, without practice, while stepping on a motorized treadmill. METHODS: Twelve infants with MMC were tested longitudinally at 1, 6, and 12 months. Electromyography was used to collect data from the tibialis anterior, lateral gastrocnemius, rectus femoris, biceps femoris. RESULTS: Across the first year, infants showed no electromyographic activity for approximately 50% of the stride cycle with poor rhythmicity and timing of muscles, when activated. Single muscle activation predominated; agonist-antagonist coactivation was low. Probability of individual muscle activity across the stride decreased with age. CONCLUSIONS: Infants with MMC show high variability in timing and duration of muscle activity, few complex combinations, and very little change over time.

Longitudinal changes in muscle activity during infants' treadmill stepping.

Previous research has described kinetic characteristics of treadmill steps in very stable steppers, in cross-sectional designs. In this study we examined, longitudinally, muscle activation patterns during treadmill stepping, without practice, in 12 healthy infants at 1, 6, and 12 mo of age. We assessed lateral gastrocnemius, tibialis anterior, rectus femoris, and biceps femoris as infants stepped on a treadmill during twelve 20-s trials. Infants showed clear changes in kinematics, such as increased step frequency, increased heel contact at touch down, and more flat-footed contact at midstance. Electromyographic data showed high variability in muscle states (combinations), with high prevalence of all muscles active initially, reducing with age. Agonist-antagonist muscle coactivation also decreased as age increased. Probability analyses showed that across step cycles, the likelihood a muscle was on at any point tended to be <50%; lateral gastrocnemius was the exception, showing an adultlike pattern of probability across ages. In summary, over time, healthy infants produce a wide variety of muscle activation combinations and timings when generating stepping patterns on a treadmill, even if some levels of muscle control arose with time. However, the kinematic stability improved much more clearly than the underlying kinetic strategies. We conclude that although innate control of limb movement improves as infants grow, explore, and acquire functional movement, stepping on a treadmill is a novel and unpracticed one. Hence, developing stable underlying neural activations will only arise as functional practice ensues, similarly to that observed for other functional movements in infancy.